2009 A4 allroad quattro

Audi is launching the A4 allroad quattro. With increased ground clearance and its permanent all-wheel drive, this baby can handle any kind of road or trail; although its tough it also offers driving pleasure - even when your on unpaved surfaces. The quattro features all the innovative technologies:

1)a range of powerful and highly energy-efficient engines.
2)Audi drive select (intelligent handling technology).
3)high-tech S tronic transmission.
4)innovative communication and assistance systems.

The vehicle will be available in early summer at a basic price of 37,100 euros.

* The A4 allroad quattro is right at home on any road - and offroad
* quattro permanent all-wheel drive and increased ground clearance
* Sporty character and innovative high-end technology

The design of the Audi A4 allroad quattro recalls the A4 Avant: crisp lines enclose tastefully curved surfaces and the low roof line establishes a coupé-like silhouette. Striking details re-interpret this model line's sporty elegance. The moon-gray single-frame radiator grille bears vertical chrome strips; an accentuated bumper and large air inlets underscore this vehicle's unique identity. Chrome rings encircle the fog lights. And in the option featuring xenon plus headlights, light-emitting diodes comprise the daytime running lights and taillights. Underneath the front end and tail end, the A4 allroad has a stainless-steel underbody guard.

Viewed from the side, the vehicle dazzles with flared wheel arches, angular sills (available with stainless-steel insert strips), and large wheels - 17-inch wheels in 7-arm design are standard. The roof is capped off by an offset rail with two high crosspieces. The width of the A4 allroad quattro is emphasized by the rear bumper's distinctive styling and the integrated horizontal reflectors. On the 2.0 TDI, the two exhaust tailpipes appear side by side; on the 2.0 TFSI and 3.0 TDI, they terminate to the left and to the right.

Final say
* The A4 allroad quattro is right at home on any road - and offroad
* quattro permanent all-wheel drive and increased ground clearance
* Sporty character and innovative high-end technology

General Maintenance Tips For Your Car

A well maintained vehicle will never let down its owner. It will not desert you when you need it most. Here are a few maintenance tips for your car

Check the Engine Oil: To prevent the engine from deterioration, its important that the engine maintains the amount of oil it is programmed to receive. Negligence in doing so will lead to a deteriorating engine performance, meaning you'll get falling mileage.

Make Sure the Lights are working properly: It is important for the lights to be properly focused, for your own and for the oncoming vehicle's safety. Travel on low beam so that it does not obstruct your view instead of helping you along.

Have Suitable Tyre Pressure: The required amount of air pressure needs to be strictly maintained if your car is to get the right mileage and pick-up. Make sure pressure is not to high or you'll shorten the life of your tyres.

Radiator Water: If your engine uses water for cooling, take care to ensure that it is regularly changed.

Some other tips...
Get your vehicle serviced only at authorized service stations
Check the engine oil level once every two weeks. Also check the levels of coolant and water in the radiator and battery.
Always use genuine spare parts.
Avoid accelerating and braking abruptly.
Shut up the engine whenever you expect to wait.
Drive at a moderate speed of 45-55 km/h to maximize fuel efficiency.
Use air-conditioning only when necessary.
Avoid riding on the clutch pedal, and release the clutch pedal fully while driving.
Maintain optimum air pressure in your tyre to improve mileage.

How To Make your engine perform more efficiently

Try increasing displacement - the more displacement means the more power you’ll because it burns more gas during each revolution of the engine (Not very feul saving). Try making the cylinders bigger or by adding more cylinders. 12 seems to be the limit.

Modify the compression ratio – You can produce more power by increasing compression ratios. The more air/fuel mixture is compressed the more power it will generate, however the more likely it is to spontaneously burst into flame (prior to the spark plug igniting it). Higher octane gasolines prevent this sort of early combustion. High-performance cars generally use high octane gasoline – because the engines use high compression ratios.

Stuff more into each cylinder - you can get more power from the cylinder, if you can cram more air (and therefore fuel) into a cylinder of a given size. Turbo chargers and super chargers pressurize the incoming air to effectively cram more air into a cylinder.

Cool the incoming air – It get pretty hot when compressing air. You would like to have the coolest air possible in the cylinder because the hotter the air is the less it will expand when combustion takes place. An intercooler is a special radiator through which the compressed air passes to cool it off before it enters the cylinder. Therefore many turbo charged and super charged cars have an intercooler.

Let air come in more easily - As a piston moves down in the intake stroke, air resistance can rob power from the engine. Air resistance can be lessened dramatically by putting two intake valves in each cylinder. Some newer cars are also using polished intake manifolds to eliminate air resistance there. Bigger air filters can also improve air flow.

Let exhaust exit more easily - If air resistance makes it hard for exhaust to exit a cylinder, it robs the engine of power. Air resistance can be lessened by adding a second exhaust valve to each cylinder (a car with 2 intake and 2 exhaust values has 4 valves per cylinder, which improves performance - when you hear a car ad tell you the car has 4 cylinders and 16 valves, what the ad is saying is that the engine has four valves per cylinder). If the exhaust pipe is too small or the muffler has a lot of air resistance then this can cause back-pressure which has the same effect. High-performance exhaust systems use headers, big tail pipes and free-flowing mufflers to eliminate back-pressure in the exhaust system. When you hear that a car has "Dual Exhaust", the goal is to improve the flow of exhaust by having two exhaust pipes instead of one.

Try making everything lighter - The lighter the piston, the less energy it takes. Lightweight parts help the engine perform better. Each time a piston changes direction it uses up energy to stop the travel in one direction and start it in another.

Inject the fuel - This improves performance and fuel economy.
Fuel injection allows very precise metering of fuel to each cylinder.

Potential causes Dieseling

An automobile engine that is dieseling will typically sputter then gradually stop rather than continue running as if the engine was not switched off at all — the latter would usually indicate an electrical fault.


Potential causes

This condition can occur for a multitude of reasons:

* Built-up carbon in the ignition chamber can glow red after the engine is off, providing a mechanism for sparking unburnt fuel. Such a thing can happen when the engine runs very rich, depositing unspent fuel and particles on the pistons and valves. Similarly, non-smooth metal regions within the piston chamber can cause this same problem, since they can glow red. It has also been suggested that an improperly rated sparkplug can retain heat and cause the same problem.

* A carburetor that does not close entirely can contribute to running once the engine is off, since the extra fuel and oxygen mixture can combust easily in the warm piston chamber. Similarly, hot vaporized oil gases from the engine crankcase can provide ample fuel for dieseling.

* Incorrect timing.

* An engine that runs too hot or too lean may produce an environment conducive to allowing unspent fuel to combust.

* An idle speed that is too fast can leave the engine with too much angular momentum upon shutdown, raising the chances that the engine can turnover and combust more fuel and lock itself into a cycle of continuous running.


Potential fixes

Items similar to carburetor cleaners and carbon cleaners have been suggested as partial remedies for attempting to clean the piston chambers and valves of engines that run too rich.

For those engines that have sharp metallic edges, it has been noted that poorly milled heads and blocks can contribute to this problem, so having the rough spots smoothed may help.

For those engines that run too hot or too lean, verify that all mechanisms in place to cool the engine properly function as they should. Replace the thermostat if necessary. Clean the radiator. Verify that all auxiliary fans engage at their proper temperatures, and ensure that the thermostatic sensors on belt driven fans engage as necessary.

In the case that there is too much angular momentum, lower the idle speed if possible.

Whats a Petcock

Is a regulator consisting of a small cock or faucet or valve for letting out air or releasing compression or draining. Although petcocks are used in a wide variety of applications, the following passage will describe one of the most common applications of the petcock which is the control of gasoline on a motorcycle engine.

Most motorcycles have a fuel petcock valve mounted on or nearby the gas tank to control the supply of gasoline. The petcock typically has three positions: ON, OFF, and RESERVE. The reserve position accesses the bottom portion of the gas tank. The reserve position functionality of the petcock is especially useful on motorcycles because they often don't possess a fuel gauge.

When operating a motorcycle the fuel management process often proceeds as follows: Especially when regarding vintage motorcycles the petcock is set to the off position when the motorcycle is not being operated. This is to eliminate fuel overflow and leakage via the carburetor(s). Before starting the engine the petcock is turned to the ON position in order to provide gasoline to the fuel delivery system.

While operating the engine there will reach a point at which fuel consumption causes the level of gasoline in the gas tank to fall below that which can be accessed by the petcock in the ON position. At that time continued operation of the engine can be maintained. This operation is achieved by accessing the remaining fuel in the gas tank via rotating the valve in the petcock to the RESERVE position.

BMW xDrive

BMW xDrive is BMW's four-wheel drive system that powers the X3, X5 and 2006 and later xd and xi 3 Series and 5 Series models.

Instead of a 60-40 (rear-front) power split (which all millennium four-wheel drive BMW's exhibit — 325xi, 330xi, early X5) with power being cut to wheels which lost traction through DSC (Dynamic Stability Control), xDrive allows power to be split between the front and rear axles through use of a multiplate clutch located between the gearbox and the Cardian shaft. This setup allows xDrive vehicles to split power in virtually any way it pleases. If the car felt like it was in a threatening situation (note not an unstable one), xDrive would react immediately, often before the driver ever knew of its intervention, to alleviate traction and control of the vehicle.

xDrive is also closely knit with DSC. In the case that wheelspin still occurs while xDrive is or has been shifting power, DSC can brake independent wheels to regain traction. xDrive also helps in cornering. When the vehicle senses that it was about to understeer or oversteer the vehicle can independently cut traction to either of the front wheels or rear wheels to help regain stability and keep the driver on the road.

xDrive was one of the first technologies used to intervene before the driver was aware that the car was becoming or would become unstable. Its intervention is transparent to the driver.

Unusual four-wheel drive systems

Prompted by a perceived need for a simple, inexpensive all-terrain vehicle for oil exploration in North Africa, the French motor manufacturer Citroën developed the 2CV Sahara. Unlike other 4x4 vehicles which use a conventional transfer case to drive the front and rear axle, the Sahara had two engines, each independently driving a separate axle, with the rear engine facing backwards. The two throttles, clutches and gearchange mechanisms could be linked, so both 12 bhp 425 cc engines could run together, or they could be split and the car driven solely by either engine. Combined with twin fuel tanks and twin batteries (which could be set up to run either or both engines), the redundancy of two separate drive trains meant that they could make it back to civilization even after major mechanical failures. Only around 700 of these cars were built, and only 27 are known to exist today. Enthusiasts have built their own "new" Saharas, by rebuilding a 2CV and fitting the modified engine, gearbox and axle onto a new, strengthened chassis.

BMC experimented with a twin-engined Mini Moke in the mid-1960s, but never put it into production.

Suzuki Motors introduced the Suzuki Escudo Pikes Peak Edition in 1996. Though actual numbers were never released, this twin-engined vehicle is believed to weigh around 1760 pounds and produce nearly 1000bhp. The engine is a twin-turbo charged 2.0L V6 mated to a sequential 6-speed manual transmission.

Nissan Motors has developed a system called E4WD wherein the rear wheels in a car that is normally front-wheel drive are driven by electric motors. This system was introduced in some variants of the Nissan Cube and Tiida.

Most recently, DaimlerChrysler's Jeep Division debuted the twin engine, 670 hp Jeep Hurricane concept at the 2005 North American International Auto Show in Detroit. This vehicle has a unique "crab crawl" capability, which allows it to rotate in 360 degrees in place. It also has dual Hemi V8s.

G60

The G60 is a supercharged straight-4 petrol engine manufactured by Volkswagen in the early 1990s. The engine displaced 1.8 L (1781 cc), had 8 valves (two per cylinder) and produced 160 PS (118 kW/158 hp). Although it was based on an existing engine, it underwent so many modifications it is usually regarded as a separate powerplant from others VW produced. It was named after the intricate "G-Lader" supercharger that it was mated to, this supercharger having a 60 mm wide displacer - hence the "G60" moniker.

The engine debuted in 1988 in the Corrado, which took 8.3 seconds to reach 100 km/h and had a maximum speed of 225 km/h (140 mph). In 1989 it was adapted for the Passat and the VW Golf Mk.II, in which it was capable of propelling the car to 100 km/h (62 mph) in 7.8 seconds, with a maximum speed of 216 km/h (134 mph). In the United States the engine was used only in the Corrado, and was dropped in 1992 in favor of the newer, more powerful VR6.

A low-production, all-wheel drive variant of the Golf G60 called the Golf Rallye was also powered by the 8-valve G60, but the engine was reduced to 1763 cc for sports homologation purposes. Power remained 160 PS. A 16-valve G60 engine was used in the ultra-rare Golf Limited, of which only 71 were produced, all with four-wheel drive. Power was raised to 210 PS (154 kW/207 hp), and the car could now reach 100 km/h in 6.4 seconds, reaching a maximum speed of 247 km/h (153 mph).

The G60 engine, like any supercharged and turbocharged engine, was sensitive to excessive air temperature, so performance very much depended on the weather conditions. Some models, like the Corrado or even some variants of the Golf Rallye, had a bigger, better-placed intercooler, resulting in increased performance over the standard intercooler and location.

Though there is no recommendation from Volkswagen, the compressor should be serviced every 100,000 km with an expensive repair likely.

A smaller version of the G60, called the G40, was used in the Polo Coupé supermini. The maximum power of this nervous little machine was 113 PS (83 kW/111 hp), propelling the car to 196 km/h (122 mph).

Centrifugal type supercharger

The centrifugal-type supercharger is an engine-driven compressor used to increase the power output of an internal-combustion engine by increasing the amount of available oxygen by compressing air that is entering the engine. This type of supercharger is practically identical in operation to a turbocharger, with the exception that instead of exhaust gases driving the compressor via a turbine, the compressor is driven from the crankshaft via a belt-, gear- or chain-drive.

Like any centrifugal pump, the boost provided by the centrifugal supercharger increases with the square of the speed, measured in RPM. This means that the centrifugal design provides little boost at low engine speeds, in some cases allowing air to pass back through the supercharger, such as during deceleration. On the other hand, the design is also the most efficient, besting designs like the Roots type supercharger and twin-screw type supercharger, which have the advantage of producing boost at any RPM.

Many World War II piston aircraft engines such as the Rolls-Royce Merlin and the Daimler-Benz DB 601 utilized single-speed or multi-speed centrifugal superchargers. Because high-performance aircraft engines were typically mated to constant-speed propellers and did not see a great variation in engine speeds, the poor low-rpm performance of centrifugal superchargers was not an issue. Turbo-supercharged engines, like some models of the Allison V-1710, combined a centrifugal supercharger with a turbocharger for better performance across a broad range of altitudes, using the engine-driven portion to provide a constant boost for extra power, while the turbocharger was used primarily to offset the effects of lowered outside air pressure as the aircraft climbed. Superchargers have since fallen from use in the aviation world, replaced by turbochargers of ever-improving quality.

Due to its design and lack of low-RPM boost it is often employed on near-standard compression engines. This means that it can facilitate airflow at higher engine RPMs, when most motors tend to have poor volumetric efficiency, without substantially increasing cylinder pressures at low- to mid-RPM operation, causing knock. This principle makes this type of supercharger ideally fit for a "bolt-on" type power adder, with no modification of the pistons and/or compression ratio necessary. Since gasoline must mix with air in a fairly narrow ratio to achieve combustion, the fact that centrifugals do not add much air at low and mid-range RPM's means fuel mileage is near-stock in the cruise RPM range. They appear to be most popular with cars that have a sufficiently large enough engine to provide adequate acceleration from a standing start without boost, while at the same time avoiding wheelspin. Then, the engine encounters breathing limitations in the mid-RPM range, often because it may only use two valves per cylinder. Centrifugals are also popular in places where the power-adder must be removed for frequent government engine inspections, as the exhaust system is unaffected (as it would be with a turbocharger).

However, detractors of the centrifugal-type supercharger (at least in street-driven automobile applications) note that it combines what some feel are the worst qualities of a turbocharger and a supercharger, since it doesn't develop appreciable boost at low RPM (Boost Threshold), but still uses up prodigious amounts of engine power to operate. Since it is crankshaft-driven and cannot benefit from a device like a wastegate on an exhaust-driven turbocharger to control its rotational speed, its boost threshold is always within a thousand or so RPM of redline. As such, the horsepower rating of the engine is greatly increased, but in a small part of the upper RPM range.

All supercharger types benefit from the use of an intercooler to reduce heat produced during compression.

Several popular makes of centrifugal type superchargers for automotive applications are: Paxton, Powerdyne, Procharger, and Vortech.

TVS SUPERCHARGER

Eaton’s new Twin Vortices Series (TVS) is a roots-type supercharger for a variety of engine applications that delivers more power and better fuel economy in a smaller package, for uncompromising, high-performance driving.

The TVS supercharger’s patented design features four-lobe rotors and high-flow inlet and outlet ports that greatly enhance thermal efficiency, deliver higher volumetric capacity, and enable higher operating speeds. The TVS supercharger is capable of running with a high thermal efficiency (up to 76 percent) across a very wide operating range.

The improvements incorporated into the TVS design allow for the use of a smaller supercharger, reducing the package size and weight of the system. The sizes range from 350cc to 2300cc per revolution, and cover engines from 0.6 liter up to large displacement V-engines. All TVS superchargers have a 2.4 pressure ratio capability and a thermal efficiency that exceeds 70 percent, which enables more compact packaging and greater output.

The twin four-lobe rotors feature 160-degree twists. The higher helix angle of the rotors coupled with a redesigned inlet and outlet ports, improves the TVS’s air-handling characteristics without increasing the overall size of the unit. The TVS improved noise and vibration characteristics eliminate additional noise-reduction treatments, complexity and system cost.

The TVS sets a new standard of boosting device performance and reaffirms Eaton’s leadership in the performance automotive market!

Roots type supercharger

The Roots type supercharger or Roots blower is a positive displacement type device which operates by pulling air through a pair of meshing lobes not unlike a set of stretched gears. Air is trapped in pockets surrounding the lobes and carried from the intake side to the exhaust. The supercharger is typically driven directly from the engine's crankshaft via a belt.

It is named for the brothers Philander and Francis Roots, who first patented the basic design in 1860 as an air pump for use in blast furnaces and other industrial applications. In 1900, Gottlieb Daimler included a Roots-style supercharger in a patented engine design, making the Roots-type supercharger the oldest of the various designs now available.

Out of the three basic supercharger types the Roots has historically been considered the least efficient. However, recent engineering developments by Eaton Corporation has resulted in a new Roots-type supercharger which yields a pump that is more efficient than all previous models. In addition, the Roots-type supercharger is simple and widely used and thus is invariably the most cost efficient. It is also more effective than alternative superchargers at developing compression at low engine rpms, making it a popular choice for passenger automobile applications. Peak torque can be achieved by about 2000 rpm.

All supercharger types benefit from the use of an intercooler to remove heat produced during compression. With a Roots-type supercharger, a thin heat exchanger is adapted to fit in-between the blower and the engine. Water is circulated through it to a second unit placed near the front of the vehicle where a fan and the ambient air-stream can dissipate the collected heat.

The Roots design is commonly used on two-stroke diesel engines, which require some form of forced induction as there is no intake stroke. In this application, the blower does not often provide significant compression and these engines are considered naturally aspirated; turbochargers are generally used when significant "boost" is needed. The Rootes Co. two-stroke diesel engine, used in Commer and Karrier vehicles, had a Roots-type blower but the two names are not connected.

The superchargers used on top fuel engines, funny cars, and other dragsters, as well as hot rods, are in fact derivatives of General Motors superchargers for their diesel engines, which were adapted for automotive use in the early days of the sport. The model name of these superchargers delineates their size; i.e. the once commonly used "6-71" and "4-71" blowers were designed for General Motors diesels having six cylinders of 71 cubic inches each, and four cylinders of 71 cubic inches each, respectively. Current competition dragsters use blowers of 14-71 design.

Checking Your Car Engine

The engine is what makes your car run. That is to say it is the most essential part of your vehicle. Checking your car engine helps a lot in maintaining an excellent performing engine.

To check this very significant auto part, stop first the engine. Let the engine oil be poured down to the oil pan. Then, pull the engine oil dipstick. Checking your owner’s manual will guide you in looking for the engine oil dipstick. Using a clean rag, any cloth or tissue, wipe it off and then. Insert it again down into its right place.

Pull the oil dipstick again. Try to check the oil level. It should be at the part of the cylinder where there is the "FULL" mark. However, it is still ok if it is quite lower. Proceed now with the checking of the oil condition. If it is not black anymore, it means you need to change it. It is still ok if it is slightly black. Any other oil color would definitely mean an engine problem.

In topping up oil engine, augment the same type and brand as you already have. This will prevent inconveniences in your engine.

Again, check the oil level. Just make sure not to overfill it. Then, return the dipstick and close the oil filler cap.

In checking automatic transmission fluid, different cars follow different procedures, so it is better to consult the owner’s manual.

Pull the transmission dipstick. Using a clean rag, wipe it off. Then, insert it back in its place.

Pull it again and go check fluid level. It should be within COLD marks if the engine is cold. If the car is warmed up, the level should be at the "HOT" mark. There is nothing to worry about if it is a bit lower.

Fluid condition must also be checked. It should be clean and transparent and has no burnt smell.

In topping up transmission fluid, it is essential to use only the specified one. You can always consult your owner’s manual or ask an auto shop to assist you in doing this. You need to be very careful in topping up transmission fluid because incorrect transmission fluid can destroy the engine.

Augment a small amount of the fluid through the dipstick pipe. For a few minutes, let the fluid to flow down. Then, recheck the fluid level. Make sure it does not overfill.

In your Acura car, Acura engine parts are the most essential auto part. Always check the engine to prevent break downs.

Honda FCX

Honda Motor Co. has finally unveiled its next-generation hydrogen fuel cell vehicle last Thursday with the announcement that it would begin producing a small number of vehicles that will be marketed in Japan and United States.

The new Honda FCX is made more sporty and sleeker as compared to the current version that has a top speed of 100 mph. It also has a longer range from 210 miles to 270 miles and of course a fuel cell power system that is 400 pounds lighter. Its auto parts such as air induction and others were also modified to function on hydrogen fuel.

The introduction of the FCX was right on timing since there is a growing concern for the greenhouse gas emissions not to mention the calls in Congress to dramatically raise fuel economy standards to minimize exhaust emissions.

Hydrogen vehicles provide lower net carbon dioxide emissions. Plus it can help end US dependency on foreign oil. Sadly this is easier said than done. The expenses that comes with building hydrogen fuel cells not to mention the absence of hydrogen fueling stations around the country creates a major obstruction for the fulfillment of this goal.

But thanks to companies like Honda which is at present is looking at an experimental home energy station that is making use of natural gas supplied to most homes to produce hydrogen fuel, hot water, heat, and electricity. According to Ben Knight, Honda’s vice president for research in the Americas, the best thing about hydrogen is that it can be extracted from a broad range of sources that includes methane or natural gas, bio-mass and renewable sources like solar or wind.

He further added that the next generation FCX is a “quantum leap forward”. The FCX will also be given a much higher price tag at least $500 more totaling to only a fraction of the approximate $1.5 million production cost of each Hydrogen fuel celled Honda.

Honda has already sold 30 units of their eco-friendly car worldwide. Mr. Knight also said that the production of the FCX model would eventually surpass the current fleet. Just to give customers a taste of what the FCX has to offer Honda has leased one to a family in California two years ago and last March another FCX was leased to a 17-year-old actress and environmental activist Q'orianka Kilcher. Honda has also allowed journalists to test drive two of its FCX. In addition government officials including top White House environmental adviser James COnnaughton were also invited to test drive Honda’s FCX.

The FCX when accelerating gives off a sound similar to a jet engine rather than a conventional gasoline engine. It is also has superior acceleration as compared to the current model that has a top speed of only 100 mph. Honda has also assured that the production vehicle will be similar to the concept showed last Thursday complete with the upgraded bumpers and revised interior.

Honda is not the only automaker that is conducting research on hydrogen vehicles; most major carmakers have spent billions on research alone. China is also investing heavily in hydrogen and if everything goes well for them they may even become the first country to adopt hydrogen vehicles in large volume.

It can be remembered that General Motors has said that it would introduce the world’s largest fleet of hydrogen-powered Chevrolte Equinox SUVs by means of its “Project Driveway” program in New York, Washington, DC, and California. And next week GM has scheduled a tour to take journalists on a 300-mile drive from its labs in Honeoye Falls, N.Y. to Tarrytown, N.Y., to update them on the progress of its hydrogen research. GM is hoping to build a 1000 vehicle fleet between 2010 and 2012.

Ford Motor Co. is also working on its plug-in electric hydrogen-powered vehicle with a range of 225 miles which will be called HySEries Edge. In addition Ford will have a fleet of hydrogen powered E-450 shuttle buses aside from hydrogen vehicles. DaimlerChrysler for its part will also be producing 100 hydrogen fuel cells to be distributed worldwide and that includes the 25 units destined for California. BMW will also be producing its own 100 Hydrogen 7 vehicles and plans to be leasing them next year.

How Extend The Life Of Your Car Battery

There are several strategies you can use to extend the life of your car battery and avoid a dead battery crisis. Regular maintenance of your automotive battery is a must, especially in extreme weather conditions. Remember over heating is bad. Check the electrolyte level in the battery. One of the easiest cleaning tips, is to make sure the terminals are clean. You can buy an cheap terminal brush and scrub off any corrosion on the battery terminals and cables. Sometimes a dead battery is nothing more than corroded terminals. Once they are clean, your car will crank right up. Car batteries also need to be recharged after deep cycle discharges and jump starts.
If you run an auto shop or other mechanical service, you will need a car battery charger to recharge your batteries. The time required to charge a car battery back to a full charge depends on the number of ampere hours (AH) depleted. Ampere hours are calculated by multiplying the number of hours times the number of Amps that the battery supplied to the load. For example, if a load was connected to a battery that used 7 Amps for 5 hours, the car battery supplied 35 Ahs. The recharge time would then be calculated by dividing 35 Ahs by the amperage charge rate of the charger. Once you are armed with this information you can make sure your batteries are fully charged and remain healthy.

If you are storing you batteries for a long period of time, such as a ski boat in winter. A trickle charger is highly recommended. These will slowly charge your battery and make sure it remains fully charged through the winter months. It is better to let the battery stay fully charged then try to recharge it in the spring. Fully discharging the battery will reduce its overall life.
By taking these simple suggestions, you can extend the life of your battery and hopefully avoid getting caught with a car that won’t start.

Engine Details of Mercedes CL 65 AMG

The outstanding qualities of the AMG V12 engine have won for it awards like the “International Engine of the Year Awards” in the “Best Performance Engine” category in the year 2004. The 450-kW/612 hp AMG power unit was proclaimed winner beating over 70 other competitors from US, Japan, and Europe.

In the manufacturing facility for the AMG engine the philosophy is “One man, one engine” which means that each AMG 12 engine is hand-assembled from start to finish by a single engineer following the strict quality standards impose by the Mercedes-Benz. The “one man, one engine” philosophy is documented by the engineer’s signature found on the AMG engine plate.

The twelve-cylinder biturbo engine found in the CL65 AMG features the latest technology from the world of motorsport. The highly flexible components and materials assured the continuous influx of power and torque even when operating at extreme temperatures. These components include high precision-balanced crankshaft that is created out from high strength materials; forged pistons made from special materials that are extremely resistant from pressure and temperature; and a more effective oil-spray cooling system with a distinct nozzle for each piston, plus some larger piston pins.

The major and big-end bearings are also made from high quality materials to counteract the pressure and the temperature more effectively. The charge cycle in the cylinder heads gets some advantage out from the optimized combustion chambers as well as on the extended opening times of the intake valves. Moreover, a modified oil pump makes sure that all the parts that need lubrication are supplied with oil even under extreme conditions. To further boost the performance of the AMG engine an engine oil cooler is also added in the front apron with the addition of an extra engine coolant radiator located in the wheel arch.

Redesigned charge-air cooler…
The charge-air cooler has also been modified with a low temperature radiator positioned in the front of the vehicle which was made almost 70 percent larger. The system functions on the precept of an air-to-water heat exchanger for an effective cooling of the intake air which are compressed by the turbochargers before they are made to enter the combustion chambers.

The extra surface area added for the low temperature radiator results in a 25 percent reduction in the intake temperature at full throttle and assures high power and torque output in any operating conditions regardless of the temperature outside.

The casing or the frame of the compressor and the turbine in both turbochargers together with the turbine and compressor wheels has been enlarged producing a maximum charge pressure of 1.5 bar.

The electronically controlled fuel supply with its new developed components functioned with a variable system pressure between 3.6 and 5.0 bar. The fuel pressure is also regulated intermittently in accordance to the required power and the temperature outside. The engine management system interprets the command from the accelerator and makes the necessary action.

AMG sports an especially designed Mercedes exhaust system…
The powerful sound of the AMG twelve-cylinder is guaranteed by the AMG sports exhaust system with two trim chromed tailpipes in the exclusive AMG V12 design. Similarly catalytic converters that has tri-metallic coating can provide a faster response from a cold start and offer an efficient exhaust-gas after treatment and an extensive service life. The CL 65 AMG also complies with the EU4 emissions standard as well as the emission requirements for the US market.

Here are the major data for the CL65 AMG

- Cylinder configuration/valves per cylinder – V12/3
- Displacement cc – 5980
- Bore x stroke mm - 82.6 x 93.0
- Compression ratio - 9.0 : 1
- Output kW/hp at rpm – 450/612;4800-5100
- Max. torque Nm at rpm - 1000 2000-4000
- Acceleration 0-100 km/h s - 4.4
- Top speed km/h - 250

The AMG Speedshift 5-speed automatic transmission and steering-wheel gearshift paddles
The driving power of the new CL65 AMG is distributed to the wheels by the AMG Speedshift 5-speed automatic transmission with AMG gearshift paddles and DIRECT SELECT gearshift. There is also an S/C/M button found on the centre console that enables drivers to choose the driving modes that they want like Manual, Comfort, and Sport driving.

The driving modes will also change the transmission characteristics and in turn alter the accelerator response and the spring/damper settings of the AMG sports suspension basing on the Active Body Control. The gears may also be shifted manually at any time by using the silver-colored aluminum shift paddles on the ergonomically designed sports steering wheel.

The AMG V12 delivers a potent torque of 1000 Nm calls for a powertrain that has been systematically reinforced. For the automatic transmission this will include newly developed clutch plates coated with high quality metallic plus the modified shift and torque converter lock-up logic. These are supplemented with the redesigned shafts, larger hub carriers and made even more durable steel spring links.

Turbocharger Tips

Turbocharger serves to pump more air into the engine boosting engine power without increasing the engine volume.
Due to its design, the turbocharger works at very high temperatures. Therefore, the requirements to the engine oil quality are much higher. Low quality, or old contaminated oil can be easily cooked under high temperature in the turbocharger causing it to fail.
Here are few tips:
- If it's not against manufacturer recommendations, use synthetic oil, or at least be very accurate with regular oil changes.

- When you stop the car after hard driving (speeding, accelerating, etc.) don't shut the engine off right away, let it idle for a while to cool down the turbocharger.

- Very long uphill driving under constant load may also cause turbo to overheat, try to avoid it if possible.

Turbocharged Direct Injection

The engine uses direct injection where a fuel injector sprays directly into the engine cylinder rather than the pre-combustion chamber prevalent in older diesels which used indirect injection. The engine is coupled with a turbocharger and intercooler to increase the amount of air that can get into the engine cylinders, thereby increasing the amount of fuel that can be injected and combusted. In combination, these allow for greater engine performance while also decreasing harmful emissions.

Other companies also use similar technology today, but "TDI" refers to these type engines. Normally-aspirated engines (those without a turbocharger) made by Volkswagen Group use the label "Saugdiesel Direct Injection" (SDI).

The reduced material volume of the direct injection diesel engine reduces heat losses and thereby increases engine efficiency, at the expense of increased combustion noise. A direct injection engine is also easier to start when cold, due to the reduced heat loss of the design.


Fuel

Like all diesel engines, TDI engines can run on petrodiesel or biodiesel. When converted properly, one can be made to also run on straight vegetable oil (SVO) or waste vegetable oil (WVO). Most conversions also make it possible to run on kerosene.

In terms of fuel efficiency, and clean emissions when run on biodiesel or SVO/WVO, TDI engines are among the best on the market. This is often overlooked because they do not drive on gasoline. The common Volkswagen 1.9L TDI, officially gets between 37-57 mpg for the automatic and 42-61 mpg for the 5-speed.

Newer TDI engines, with higher injection pressures, are less forgiving about poor-quality fuel than their 1980s ancestors. No. 2 diesel fuel is recommended since it has a higher cetane number than No. 1 fuel and has lower viscosity (better ability to flow) than heavier fuel oils. Many enthusiasts have converted their TDI cars to run on SVO or WVO by installing devices that pre-heat the oil to lower its viscosity, as the viscosity of unrefined oil is much higher than petrodiesel or biodiesel.

Volkswagen of America does not endorse the use of biodiesel in high percentages. They state that "[s]hould the use of substandard fuels, or higher level blends of biodiesel, damage your engine or fuel system, such damage cannot be covered under warranty." Thus a high-percentage biodiesel user who encounters fuel system problems can reasonably expect difficulty obtaining service under warranty if the biodiesel use is apparent to the dealer.

Changing the Fuel Filter

A vehicles fuel filter is used to keep the fuel that is used in the fuel injection system clean to avoid plugging fuel injectors and fuel pressure regulator. The fuel filter should be changed between 25,000 and 35,000 miles depending on driving conditions. First locate and identify the fuel filter, all vehicles are different so you might have to look around for it. Some are under the hood and others are under the car or truck like the one used in this example.

If you are unsure were your fuel filter is located then you can buy an online schematic at Mitchell1 Online. (Wear protective gloves and eyewear when replacing).

Locate and replace the fuel filter
Remove the fuel filter connection

Remove fuel filter connections from fuel lines. A small amount of fuel will leak out when connections are removed. Next remove the fuel filter mounting bracket bolt and remove filter.

Install fuel filter mount

Remove fuel filter mount from old fuel filter and install it on the new fuel filter. Make sure that the direction arrow is pointing in the direction of the engine. (forward in most cases)

Install new fuel filter

After the fuel filter mount is installed reinstall fuel filter. Make sure the sealing "O" rings are in place, in good condition and free from debris. Remount filter and reconnect. Start vehicle to check for leaks

Advantages and Disadvantages of Manual Transmission

Advantages

* Manual transmissions typically offer better fuel economy than automatics. Increased fuel economy with a properly operated manual transmission vehicle versus an equivalent automatic transmission vehicle can range from 5% to about 15% depending on driving conditions and style of driving -- extra urban or urban (highway or city). There are several reasons for this:
o Mechanical efficiency. The manual transmission couples the engine to the transmission with a rigid clutch instead of a torque converter that introduces significant power losses. The automatic transmission also suffers parasitic losses by driving the high pressure hydraulic pumps required for its operation.
o Driver control. Certain fuel-saving modes of operation simply do not occur in an automatic transmission vehicle, but are accessible to the manual transmission driver. For example, the manual-transmission vehicle can be accelerated gently, yet with a fully open throttle (accelerator pedal to the floor), by means of shifting early to a higher gear, keeping the engine RPM in a low power band. By contrast, in an automatic transmission, the throttle position serves as the indicator of how fast the driver wishes to accelerate. If the accelerator pedal is floored, the transmission will shift to a lower gear, resulting in high engine RPM and aggressive acceleration. The thermodynamically efficient combination of open throttle and low RPMs is unavailable to the automatic transmission driver. Fuel-efficient acceleration is important to achieving fuel economy in stop-and-go city driving.
o Fuel cut-off. The torque converter of the automatic transmission is designed for transmitting power from the engine to the wheels. Its ability to transmit power in the reverse direction is limited. During deceleration, if the torque converter's rotation drops beneath its stall speed, the momentum of the car can no longer turn the engine, requiring the engine to be idled. By contrast, a manual transmission, with the clutch engaged, can use the car's momentum to keep the engine turning, in principle, all the way down to zero RPM. This means that there are better opportunities, in a manual car, for the electronic control unit (ECU) to impose deceleration fuel cut-off (DFCO), a fuel-saving mode whereby the fuel injectors are turned off if the throttle is closed (foot off the accelerator pedal) and the engine is being driven by the momentum of the vehicle. Automatics further reduce opportunities for DFCO by shifting to a higher gear when the accelerator pedal is released, causing the RPM to drop.[citation needed]
o Geartrain efficiency. Automatics may require power to be transmitted through multiple planetary gearsets before attaining the desired gear ratio. In comparison, manual transmissions usually transmit power through one or two gearsets at most.

* Manual transmissions are still more efficient than belt-driven continuously-variable transmissions.

* Manual transmissions are generally significantly lighter than torque-converter automatics.

* Vehicles with manual transmissions are typically cheaper than those with automatic transmissions.

* Manual transmissions generally require less maintenance than automatic transmissions.

* Manual transmissions normally do not require active cooling, because not much power is dissipated as heat through the transmission.
o The heat issue can be important in certain situations, like climbing long hills in hot weather, particularly if pulling a load. Unless the automatic's torque converter is locked up (which typically only happens in an overdrive gear that would not be engaged when going up a hill) the transmission can overheat. A manual transmission's clutch only generates heat when it slips, which does not happen unless the driver is riding the clutch pedal.

* A driver has more direct control over the state of the transmission with a manual than an automatic. This control is important to an experienced, knowledgeable driver who knows the correct procedure for executing a driving maneuver, and wants the machine to realise his or her intentions exactly and instantly. Manual transmissions are particularly advantageous for performance driving or driving on steep and winding roads. Note that this advantage applies equally to manual-automatic transmissions, such as tiptronic.
o An example: the driver, anticipating a turn, can downshift to the appropriate gear while the steering is still straight, and stay in gear through the turn. This is the correct, safe way to execute a turn. An unanticipated change of gear during a sharp turn can cause skidding if the road is slippery.
o Another example: when starting, the driver can control how much torque goes to the tires, which is useful for starting on slippery surfaces such as ice, snow or mud. This can be done with clutch finesse, or possibly by starting in second gear instead of first. The driver of an automatic can only put the car into drive, and play with the throttle. The torque converter can easily dump too much torque into the wheels, because when it slips, it acts as an extra low gear, passing through the engine power, reducing the rotations while multiplying torque. An automatic equipped with ESC, however, does not have this disadvantage. Some cars, such as the Saab NG900 Automatic transmission, have a special mode for low traction situations.
o Yet another example: passing. When the driver is attempting to pass a slower moving vehicle by making use of a lane with opposite traffic, he or she can select a lower gear for more power at exactly the right moment when conditions are right to begin the maneuver. Automatics have a delayed reaction time, because the driver can only indicate his intent by pressing the throttle. The skilled manual transmission driver has an advantage of superior finesse and confidence in such situations.

* Driving a manual requires more involvement from the driver, thereby discouraging some dangerous practices. The manual selection of gears requires the driver to monitor the road and traffic situation, anticipate events and plan a few steps ahead. If the driver's mind wanders from the driving task, the machine will soon end up in an incorrect gear, which will be obvious from excessive or insufficient engine RPM. Related points:
o It's much more difficult for the driver to fidget in a manual transmission car, for instance by eating, drinking beverages, or talking on a cellular phone without a headset. During gear shifts, two hands are required. One stays on the wheel, and the other operates the gear lever. The hand on the wheel is absolutely required during turns, and tight turns are accompanied by gear changes. If the hand leaves the wheel, the steering will begin to straighten. In general, the more demanding the driving situation, the more difficult it is for the manual driver to do anything but operate the vehicle. The driver of an automatic transmission can engage in distracting activities in any situation, such as sharp turns through intersections or stop-and-go traffic.
o The driver of a manual transmission car can develop an accurate intuition for how fast the car is traveling, from the sound of the motor and the gear selection. It's easier to observe the lower speed limits—like 30 km/h and 50 km/h or their U.S. and Imperial counterparts, 20 mph and 30 mph—without glancing at the instrumentation.

* Cars with manual transmissions can often be started when the battery is dead by pushing the car into motion or allowing it to roll downhill, and then engaging the clutch in third or second gear. This is commonly known as a "push start", "popping the clutch" (in the USA) or Bump starting, which in the UK describes the action of suddenly releasing the clutch pedal after putting it in gear.

* Manual transmissions work regardless of the orientation angle of the car with respect to gravity. Automatic transmissions have a fluid reservoir (pan) at the bottom; if the car is tilted too much, the fluid pump can be starved, causing a failure in the hydraulics. This could matter in some extreme off roading circumstances.

* It is sometimes possible to move a vehicle with a manual transmission just by putting it in gear and cranking the starter. This is useful in an emergency situation where the vehicle will not start, but must be immediately moved (from an intersection or railroad crossing, for example). It is also easier to put a car with a manual transmission into neutral, even when the transmission has suffered damage from an accident or malfunction. Many modern vehicles will not allow the starter to be run without the clutch fully depressed, negating this advantage, but some manufacturers have begun to add a clutch start override switch so that this advantage may still be enjoyed when necessary.



Disadvantages

Many of the disadvantages of a manual transmission involve the driver interaction with the vehicle. While most of these can be overcome with practice and experience, they should be considered:

* Manual transmissions often require the driver to place their full and continuous attention on the road, which may be seen as a disadvantage. Some consider this an advantage, as it prevents the driver from other potential distractions like cell phone or radio use.

* Inexperienced drivers may place more of their attention on shifting the gears, potentially distracting them from the road surroundings.

* A driver may inadvertently shift into the wrong gear with a manual transmission, potentially causing damage to the engine and transmission, or the vehicle's body and its surroundings if the intended gear was reverse. However this can be offset with a lockout on the reverse such as found on many European cars.

* Manual transmissions require a learning curve as one must develop a feel for properly engaging the clutch.

* While it can easily be overcome with experience, manual transmission vehicles require good gas pedal application and clutch control when starting the car from a standstill. Too many RPM's causes the car to redline, whereas not enough RPM's upon clutch release causes the engine to stall, due to the lack of momentum required to sustain the engine.

* The smooth and quick shifts of an automatic transmission are not guaranteed when operating a manual transmission; such changes are dependent on the driver.

* Manual transmission places more work on the driver in heavy traffic situations since the driver is constantly clutching, in comparison with automatic transmission which merely require moving the foot from the gas pedal to the brake pedal and vice versa. Manual-transmission automobiles can also be slower to take off from traffic lights and roundabouts because of the subsequent gear changes required during the process of driving away from these.

* For a person with physical impairment, an automatic transmission might be the only available shifting option. The comparable systems for hand-operated clutch and brakes for a manual-transmission-equipped car are usable only by people with just lower body handicap. Retrofit of such a system also requires extensive modifications to the car.

* Vehicles with manual transmissions are more difficult to start from rest when stopped upward on a hill because the clutch must be depressed and the gas applied very quickly once the brake is removed to prevent slipping backward. However, this can be overcome with experience and/or the use of the handbrake.

* The clutch disc is a wear item and must be replaced periodically. While this is typically a labor intensive process that can be an expensive service, it shouldn't prove more expensive than periodic service to an automatic transmission in the long run

Increase Fuel Efficiency and Decrease Emissions with Atomization and Spray Technology

Legislation in the US, Europe and Asia demands progressive increases in energy efficiency, coupled with reductions in emissions of pollutants in gasoline, diesel and gas turbine engines for vehicles, aircraft and power plants. Combustion reaction, temperature and formation of pollutants are directly related to the distribution of air/fuel mixtures ratios throughout combustion chambers. The local mixture ratios are determined by vaporization of droplets in liquid fuel sprays. Evaporated fuel distribution is governed by drop diameter, velocity and trajectory as individual droplets traverse through airflow fields and deposit fuel in individual droplet wakes.

The design of atomizer nozzles, liquid fuel and atomizing air pressures and flow rates are important tools for controlling and changing breakup of liquid jets, spray angle droplet size and velocity distributions, The most efficient and energy saving combustion is with stoichiometric (perfect) air fuel mixture ratios where all fuel is consumed. However, these conditions create elevated temperatures that generate high formation of oxides of nitrogen – a major pollutant. The ideal fuel injection system requires pre-determined local air/fuel ratio distribution for maximum combustion and energy efficiency and minimum generation of pollutants. Spray characteristics, individual drop size and momentum are the most important factors for achieving the required local air/fuel ratio distributions.

Many years of research and development in spray science and technology have provided greater insight, knowledge and understanding of the physical mechanisms of breakup of liquid jets, formation of drops and spray characteristics. Atomizer designs include co-axial air assist, liquid and air swirl, pizo-electric induced fluctuations, effervescent bubble atomization, rotating cup and disk. Electrostatic charging of droplets allows deflection of droplets in flight and avoidance of deposition on surfaces. Sprays used in combustion and industrial systems have not been sufficiently optimized. By increased knowledge, understanding and control, optimum conditions can be prescribed to allow designs of atomizers, liquid and air flows that will result in significant increases in fuel and energy efficient as well as significant reductions in formation and emission of pollutants.

Anti-Lag System

Anti-Lag System, ALS, is a system used on mainly turbocharged racing and rally engines to eliminate turbo lag. It was used in the early days of turbo charging in F1 until fuel restrictions made its use unsuitable. Later it became a common feature in rally cars due to the mandated restrictors on the turbocharger inlet. Because of the pressure drop across the restriction, the pressure ratio for a given boost level is much higher and the turbocharger must spin a lot faster to produce the same boost as before. This increases turbo lag significantly compared to unrestricted turbochargers.

An ALS system requires an air bypass, and generally this is done in one of two ways. The first method is to use a throttle air bypass; this may be an external bypass valve or a solenoid valve which open up the throttle 12-20 degrees. This allows air to bypass the closed throttle and to reach the engine. The second method is to use a bypass valve which feed charge air directly to the exhaust manifold.

The throttle bypass/throttle solenoid system is combined with ignition retardation and slight fuel enrichment (mainly to provide cooling), typically ignition occur at 35-45° ATDC. This late ignition causes very little expansion of the gas in the cylinder; hence the pressure and temperature will still be very high when the exhaust valve opens. At the same time, the amount of torque delivered to the crankshaft will be very small (just enough to keep the engine running). The higher exhaust pressure and temperature combined with the increased mass flow is enough to keep the turbocharger spinning at high speed thus reducing lag. When the throttle is opened up again the ignition and fuel injection goes back to normal operation. Since many engine components are exposed to very high temperatures during ALS operation and also high pressure pulses, this kind of system is very hard on the engine and turbocharger. For the latter not only the high temperatures are a problem but also the uncontrolled turbo speeds which fast can destroy a turbocharger. In most applications the ALS is automatically shut down when the coolant reaches a temperature of 110-115°C, this to prevent overheating the engine.

An ALS system working with a bypass valve which feeds air directly to the exhaust system can be made more refined than the system described above. Some early systems used by Ferrari in F1 followed this approach, so does the anti-lag systems used in WRC today, which are even more refined with advanced computer control. Today this kind of system has reached such a refinement that it’s even possible to use the system in a road car. A recent example is the Prodrive P2 prototype. The system works by bypassing charge air directly to the exhaust manifold which acts as a combustor when fuel rich exhaust from the engine meets up with the fresh air from the bypass. This will provide a continuous combustion limited to the exhaust manifold which significantly reduces the heat and pressure loads on the engine and turbocharger. With the latest anti-lag systems the bypass valve can not only be opened or closed but it can actually control the flow of air to the exhaust manifold very accurately. The turbocharger is fitted with a turbo speed sensor and the engine management system has a map based on throttle position and car speed which is used to find a suitable turbocharger speed and boost pressure for every condition. When the engine alone can’t provide enough exhaust energy to reach the turbo speed/boost demanded by the management system, the bypass valve opens and exhaust manifold combustion begins. This not only reduces turbo lag, but it also allows boost to be produced at very low engine speeds where boost was previously limited by compressor surge or exhaust energy. With relatively high boost at low speeds, this makes the low end torque superior even to large naturally aspirated engines. The system also operates very quietly.

Whats a Turbo timer?

A turbo timer is a device designed to keep an automotive engine running for a pre-specified period of time in order to automatically execute the cool-down period required to prevent premature turbo wear and failure. After a period of driving when a turbocharger has been working hard, it is important to let the engine run at idle speed for a period of time, allowing the compressor assembly to run down in speed and cool from the lower gas temperatures in both the exhaust and intake tracts. At the same time the lubricating oil from the engine is able to circulate properly so the turbine won't burn the lubricating oil that would otherwise be trapped within the charger with the turbine rotating at high speed. With regard to modern automotive turbochargers, the need for a turbo timer can be eliminated by simply ensuring the car does not produce any 'boost' (during driving) for several minutes prior to the ignition being shut off.

Benefits of Engine Balancing

Balancing goes hand-in-hand with performance engine building. Balancing reduces internal loads and vibrations that stress metal and may eventually lead to component failure. But is it worth the time and effort for mild performance applications, everyday passenger car engines or low-buck rebuilds?

From a technical point of view, every engine regardless of the application or its selling price can benefit from balancing. A smoother-running engine is also a more powerful engine. Less energy is wasted by the crank as it thrashes about in its bearings, which translates into a little more usable power at the flywheel. Reducing engine vibration also reduces stress on motor mounts and external accessories, and in big over-the-road trucks, the noise and vibration the driver has to endure mile after mile.

Though all engines are balanced from the factory (some to a better degree than others), the original balance is lost when the pistons, connecting rods or crankshaft are replaced or interchanged with those from other engines. The factory balance job is based on the reciprocating weight of the OE pistons and rods. If any replacements or substitutions are made, there’s no guarantee the new or reconditioned parts will match the weights of the original parts closely enough to retain the original balance. Most aftermarket replacement parts are "balanced" to the average weight of the OEM parts, which may or may not be close enough to maintain a reasonable degree of balance inside the engine. Aftermarket crank kits are even worse and can vary considerably because of variations within engine families.

If the cylinders are worn and a block needs to be bored to oversize, the larger replacement pistons may be heavier than the original ones. Some piston manufacturers take such differences into account when engineering replacement pistons and try to match "average" OE weights. But others do not. Most high performance pistons are designed to be lighter than the OE pistons to reduce reciprocating weight for faster acceleration and higher rpm. Consequently, when pistons and rods are replaced there’s no way of knowing if balance is still within acceptable limits unless you check it.

If you’re building a stock engine for a passenger car or light truck that will spend most of its life loafing along at low rpm, your customer might question the value of balancing such an engine. But if a customer values durability and smooth operation, selling them a balance job shouldn’t be too difficult – and it will add some extra profit, too.

On the other hand, if you’re building a performance motor, a stroker motor or an engine that’s expected to turn a lot of rpms or run a lot of miles, balancing is an absolute must. No engine is going to survive long at high rpms if it’s out of balance. And no engine is going to last in a high mileage application if the crank is bending and flexing because of static or dynamic imbalances.

Campro engine

Campro engine is the first automotive engine ever developed by the Malaysian automotive corporation, Proton. The name Campro is short for Cam Profile. This engine powers the Proton Gen-2, the Proton Satria Neo, the Proton Waja Campro as well as Proton's future models. The Campro engine is aimed to show Proton's ability to make their own engines that produces good power output and meets newer emission standards.


Basic DOHC engine

The basic Campro engine coded as S4PH is a basic DOHC 16-valve 1.6 L engine that produces 110 bhp (82 kW) @ 6,500 rpm of horsepower and 148 N-m of torque. This is the engine that powers the Proton Gen-2. The S4PH engine can be fitted with Cam Profile Switching (CPS) and Variable Inlet Manifold (VIM) technology. Besides this 1.6 L engine, Proton has produced the 1.3 L version of the Campro engine.

Even though the S4PH engine seems to be quite powerful at higher revs, its performance is reportedly sluggish at lower revs and this is proven by driving the Gen-2 uphills where drivers who drive the manual transmission version have to shift a lot between 2nd gear and 3rd gear. This is due to its torque dip between 3,000 ~ 3,500 rpm where the torque decreases slightly before picking up back to the maximum torque at 4,000 rpm.

Before the engine is ready to be installed in the Gen-2 cars, Proton installed the engine in the Waja specialized for on-road tests.

Currently the Campro engines installed in the Gen-2 has none of the promised cam profile switching (CPS) and variable inlet manifold technologies. No date nor any information has been known as to when Proton will equip its models with the promised full-spec engine.

Another engine option for the basic DOHC engine is a 1.3L engine coded as S4PE. While the power output of S4PH engine can't be considered as impressive, the S4PE engine produces 94 bhp (70 kW) @ 6,000 rpm and the torque of 120 N-m @ 4,000 rpm, much more powerful than most 1.3L rivals, even with variable valve timing technology.

The bore x stroke dimensions for both engines are as follows:-

* S4PH (1.6L): 76 x 88 mm, resulting the displacement of 1597 cc.
* S4PE (1.3L): 76 x 73.4 mm, resulting the displacement of 1332 cc.


Campro CPS and VIM engine

In addition to the basic DOHC engine, Proton developed its own variable valve timing technology that works similar with other variable valve technologies such as Honda VTEC and Toyota VVTi, named as CPS (Cam Profile Switching) technology. The usage of CPS tehnology will raise the maximum power up to about 127 bhp and will improve the low-end torque to its maximum value which will maintain until about 5,000 rpm. The technology is said to be applied to newer Gen-2s and future models starting from the end of 2005, but currently the CPS technology is still under testing.

The Campro's Variable Intake Manifold technology is currently being developed by Robert Bosch GmbH, and is expected to make it's debut in the second half of 2007.


Campro GDI engine

Recently, Proton is developing their own gasoline direct injection version of Campro engines which will be used in the future. Currently, the Campro GDI engine is still under research and development, therefore very little information available for the Campro GDI engine.


Supercharged Campro engine

Recently, Proton has announced to collaborate with Kleemann, the company that supplies superchargers for Mercedes-Benz compressor models for the coming Proton Satria replacement model. Little is known about the engine, but the engine is rumored as a 1.8L engine equipped with a supercharger supplied by Kleemann. Mercedes-Benz usually sources its superchargers from Eaton Corporation.


Hybrid Campro engine

Recently, Proton and Lotus have announced their concept model of a Proton Gen-2 powered by a hybrid powerplant that uses the Campro engine. The concept model will be revealed during the 2007 Geneva Motor Show from 8 ~ 18 March 2007.

The hybrid powerplant system, which is known as EVE system (Efficient, Viable, Environmental) will be using the same S4PH engine as the one that powers the present gasoline version of the Gen-2, combined together with a 30 kW, 144V electric motor. The main purpose of the hybrid powerplant system is to provide a hybrid system that can be retrofitted to existing models, retaining the same powerplant and also eliminates the need to develop a completely different platform, like the Honda Civic Hybrid.

The EVE Hybrid System will have 3 key technologies:-

1. "Micro-hybrid" start-stop system - An integrated starter-alternator system is installed to switch off the engine automatically when the engine stops, for example at the traffic light. The engine will automatically restart when the gas pedal is depressed.

2. Full parallel hybrid technology - Combines the existing S4PH engine with a 30 kW, 144V electric motor, resulting in higher power (141 bhp combined), higher torque (233 N-m combined), lower emission (up to 22% carbon dioxide reduction) and better fuel economy (up to 28%). The system also includes regenerative braking system.

3. Continuously Variable Transmission (CVT) - The CVT system provides an infinite number of gear ratios for better efficiency.

The combined power and torque for the powerplant system are as follows:-

* Max power (gasoline engine only): 110 bhp (82 kW) @ 6,000 rpm
* Max torque (gasoline engine only): 148 N-m @ 4,000 rpm
* Max power (combined): 141 bhp (105 kW) @ 5,500 rpm
* Max torque (combined): 233 N-m @ 1,500 rpm (limited to 180 N-m continuous)

General Motors XV8 engine

The all-new engine provides the power of a full-size, high-end V8, but has greater fuel efficiency, the width of a V-6, and the length of a four-cylinder.

With an aluminum block and head, the 4.3 liter XV8 has three valves per cylinder with an air-assisted direct fuel injection system and two camshafts in the block. Power ratings are 300 horsepower (224 kW) and 295 lb-ft (400 Nm) of torque.

Other features include variable inlet systems (currently the main feature of Chrysler's Magnum engines), cam phasing, and displacement on demand (first seen on the ill-fated Cadillac 4-6-8 engines), variable inlet valve timing (common to Toyota and Honda engines), a narrow 75-degree bank angle, twin oil pumps, and an integrated air compressor. A GM spokesman said this combination was possible, in its best form, because of the engine's clean-sheet design: there was no need to compromise new features to co-exist with existing designs. That was especially important for direct injection.

The XV8's compression ratio of 10.75:1 is achieved with regular gasoline.
Key features

The all-aluminum 4.3-liter XV8 utilizes a unique three-valves-per-cylinder combustion chamber configuration, supporting the optimization of an air-assisted direct fuel injection system. The configuration features an industry first: two camshafts in the block. The XV8 produces 224 kW (300 horsepower) and 400 Nm (295 lb-ft) of torque.

The air-assisted direct injection gasoline system was developed by Orbital Engine Corp. of Australia, and is integrated into three-valve cylinder heads and dual cams in the block. The three valve system (two inlet valves, one exhaust) provides more room in the combustion chamber for optimal positioning of the injector and the spark plug, vertical and nearly central in the chamber - positioned as they would be in a Hemi engine.

Having two cams in the block rather than dual overhead cams provides considerable packaging benefits and combined with the direct injection fuel system, contributes to the XV8's outstanding performance numbers. The clean burning also means that after-combustion pollution control can be milder.

GM's Displacement on Demand technology allows the V8 to shut down half of its cylinders seamlessly at predetermined times to significantly reduce fuel consumption without hampering performance.

The unique twin oil pump design allows the engine to run Displacement on Demand at idle, since the system and cam phasing system have their own dedicated oil pump, which provides enough pressure to deactivate the cylinders at idle and reactivate them immediately upon throttle engagement.

The use of a camshaft "phaser" separates the timing functions of the intake and exhaust valves. This is accomplished in the XV8 engine by having two in-block camshafts, one for inlet operation and one for exhaust. The camshafts are located in a vertical plane above the crankshaft and parallel to its center of rotation. The intake camshaft is the lower camshaft and is approximately in the center of the block. The exhaust cam is positioned above the intake. Because the intake camshaft rather than the exhaust is "phased," the XV8's camshaft drive provides the ability to better modify and enhance full-load engine torque characteristics. In the stratified combustion mode of operation, it can be used to increase the charge dilution by advancing the intake cam timing. The set-up reduces friction and fuel consumption, particularly at idle and part-load, and also contributes to the engine's outstanding low-end torque. Having two camshafts in the engine block with the ability to "phase" one of the cams is unique to GM.

"With the cams in the block," GM's Fritz Indra said, "the valve timing precision is better than with a DOHC configuration. The different heat levels with long belts and chains in a DOHC set-up always changes the valve timing."

The air-assist direct injection system requires port geometries that generate a minimum of "in-cylinder" motion when the system is operating in stratified mode. During homogeneous operating conditions, in-cylinder motion is required in similar fashion to port fuel injected engines. The inlet manifold design supports these design objectives to achieve maximum fuel economy. The resulting design also allows the engine to deliver a broad torque band suited to spirited driving styles, supports the peak power objectives, and fully accommodates the Displacement on Demand system.

The XV8 is unique not only in that it has two oil pumps, but also in that the engine's balance shaft doubles as the oil pump drive shaft. The former allows for such functions as cam phasing and Displacement on Demand at idle and the latter contributes to the engine's compact packaging.

Because the XV8 requires extensive hydraulic function, two oil pumps were used in a serial fashion. If the lubrication system was designed with the typical single oil pump, its displacement would have to be substantially increased to provide minimum pressure to the entire engine. The primary pump supplies low pressure filtered oil to the bearings, valve lifters and secondary pump inlet. The secondary pump acts to intensify the pressure for supply to the cam phaser and Displacement on Demand systems. In doing this, parasitic power consumption to the oil pump is minimized.

Because of packaging constraints, the oil pump drive was combined with the balance shaft assembly. To get the necessary 1:1 counter-rotation of the balance shaft, it is driven by a helical gear pressed on the rear of the crankshaft.

"The drive for the pumps is the balance shaft, which has to go opposite engine rotation at engine speed because of our narrow bank angle," GM's Alan Hayman said. "So we get the balance shaft basically for free and this is all packaged in the sump that bolts to the bottom of the block. That is unique. Also, placing the oil pumps at each end of the balance shaft helps to damp vibrations."

The XV8's air compressor is integrated into the engine assembly. "That's another unique aspect of the engine," Hayman said. "The air compressor is part of the engine assembly itself, not just a component bolted onto the accessory drive somewhere as a stand alone pump. It's integrated to the back of the cylinder head and all of the fluids are transferred through this interface. This avoids the requirement for the myriad of hoses that would have traditionally been required including the avoidance of having to run a separate air-assist rail."

Buick Small-Block

In 1961 Buick unveiled an entirely new small V8 engine with aluminum cylinder heads and cylinder block. Lightweight and powerful, the aluminum V8 also spawned a turbocharged version, (only in the 1962-63 Oldsmobile Cutlass version), the first ever offered in a passenger car. It became the basis of a highly successful cast iron V6 engine, the Fireball. The all-aluminum engine was dropped after the 1963 model year, but was replaced with a very similar cast-iron engine.


215

GM experimented with aluminum engines starting in the early 1950s, and work on a production unit commenced in 1956. Originally intended for 180 in³ (2.9 L) displacement, Buick was designated by GM as the engine design leader, and decided to begin with a larger, 215 in³ (3.5 L) size, which was deemed ideal for the new "senior compact cars" introduced for the 1961 model year. This group of cars was commonly called the BOP group or A-bodies.

The 215 had a 4.24 in (107.7 mm) bore spacing, a bore of 3.5 in (88.9 mm), and a stroke of 2.8 in (71.1 mm), for an actual displacement of 3533 cc. The engine was the lightest mass-production V8 in the world, with a dry weight of only 318 lb (144 kg). It was standard equipment in the 1961 Buick Special.

Oldsmobile and Pontiac also used the all-aluminum 215 on its mid-sized cars, the Oldsmobile F-85 and Pontiac Tempest. However the Oldsmobile version of this engine, although sharing the same basic architecture, had cylinder heads designed by Oldsmobile engineers, and was produced on a separate assembly line. Among the differences between the Oldsmobile and Buick versions, it was somewhat heavier, at 350 lb (159 kg). The design differences were in the cylinder heads: Buick used a 5-bolt pattern around each cylinder where Oldsmobile went to a 6-bolt pattern. The 6th bolt was added to the intake manifold side of the head, one extra bolt for each cylinder. This was supposed to alleviate the head-warping problems that came about on the higher compression ratio versions. Later Rover versions of the aluminum block and subsequent Buick iron small blocks (300, 340 and 350) went to a 4 bolt per cylinder pattern.

At introduction, Buick's 215 was rated 150 hp (112 kW) at 4400 rpm. This was raised soon after introduction to 155 hp (116 kW) at 4600 rpm. 220 ft·lbf (298 N·m) of torque was produced at 2400 rpm with a Rochester 2GC two-barrel carburetor and 8.8:1 compression ratio. A mid-year introduction was the Buick Special Skylark version, which had 10.25:1 compression and a four-barrel carburetor, raising output to 185 hp (138 kW) at 4800 rpm and 230 ft·lbf (312 N·m) at 2800 rpm.

For 1962, the four-barrel engine increased compression ratio to 11.0:1, raising it to 190 hp (142 kW) at 4800 rpm and 235 ft·lbf (319 N·m) at 3000 rpm. The two-barrel engine was unchanged. For 1963 the four-barrel was bumped to an even 200 hp (149 kW) at 5000 rpm and 240 ft·lbf (325 N·m) at 3200 rpm, a respectable 0.93 hp/in³ (56.6 hp/liter).

Unfortunately, the great expense of the aluminum engine led to its cancellation after the 1963 model year. The engine had an abnormally high scrap ratio due to hidden block-casting porosity problems, which caused serious oil leaks. Another problem was clogged radiators from antifreeze mixtures incompatible with aluminum. It was said that one of the major problems was because they had to make extensive use of air gaging to check for casting leaks during the manufacturing process, and not being able to detect leaks on blocks that were as much as 95% complete. This raised the cost of complete engines to more than that of a comparable all cast-iron engine. Casting sealing technology was not advanced enough at that time to prevent the high scrap rates.

The Buick 215's very high power to weight ratio made it immediately interesting for automotive and marine racing. Mickey Thompson entered a stock-block Buick 215-powered car in the 1962 Indianapolis_500. From 1946 to 1962 there hadn't been a single stock-block car in this famous race. In 1962 the Buick 215 was the only non-Offenhauser powered entry in the field of 33 cars. Rookie driver Dan_Gurney qualified eighth and raced well for 92 laps before retiring with transmission problems.

Surplus engine blocks of the Oldsmobile (6 bolt per cylinder) version of this engine formed the basis of the Formula One Repco V8 used by Brabham to win the 1966 and 1967 Formula One championship. No other American stock-block engine has won a Formula One championship.

Buick 215s have been engine swapped into countless sports cars including especially Chevrolet Vegas and MG sports cars. The engine remains well supported by enthusiast clubs, specialist parts suppliers, and by shops that specialize in these conversions.

The Buick 215 was used in a small sports car known as the Apollo from 1962 to 1963, and also in the Asardo 3500 GM-S show car.

Although dropped by GM in 1963, in January 1965 the tooling for the aluminum engine was sold to Britain's Rover Group to become the Rover V8 engine, which would remain in use for more than 35 years. GM tried to buy it back later on, but Rover declined, instead offering to sell engines back to GM. GM refused this offer.


300

In 1964 Buick replaced the 215 with an iron-block engine of very similar architecture. The new engine had a bore of 3.75 in (95.5 mm) and a stroke of 3.40 in (86.4 mm) for a displacement of 300.4 cu. in. (4.9 L). It retained the aluminum cylinder heads, intake manifold, and accessories of the 215 for a dry weight of 405 lb (184 kg). The 300 was offered in two-barrel form, with 9.0:1 compression, making 210 hp @ 4600 rpm and 310 ft·lbf @ 2400 rpm, and four-barrel form, with 11.0:1 compression, making 250 hp @ 4800 rpm and 335 ft·lbf @ 3000 rpm.

For 1965 the 300 switched to a cast-iron heads, raising dry weight to 467 lb (212 kg), still quite light for a V8 engine of its era. The four-barrel option was cancelled for 1966, and the 300 was replaced entirely by the 350 in 1968.

The Apollo sports car, also known as the Vetta Ventura, used this engine.


340

The 340 in³ (5.6 L) 340 was a stroked (to 3.85 in/97.8 mm) version of the 300. It had a two-barrel or four-barrel carburetor, the two barrel with 220 hp, and the four barrel with 11.0:1 compression, rated at 260 hp @ 4200 rpm and 365 ft·lbf @ 2800 rpm. It replaced the four-barrel 300 for 1966. It was produced only in 1966 and 1967, with the new Buick 350 taking its place after that.


350

Buick adopted the popular 350 in³ (5.7 L) size with their final family of V8s. Although sharing the displacement of the Chevrolet Small-Block engine family, the Buicks were substantially different.

The Buick 350 V8 had a 3.80 in bore (like the 231) and retained the 3.85 in stroke of the 340. It was introduced in 1968 and produced through 1980.

The major differences of the Buick 350 when compared to other GM V8's are, deep skirt block construction, higher nickel-content cast iron, external oil pump, under square bore sizing, 3.0" crank main journals, and 6.5" connecting rods. It is an extremely rugged and durable engine, and some of the design characteristics of the Buick 350 are found in modern GM engines such as the 231 V6, and Series I, II, and III 3800 V6's.

Of all the GM 350-inch engines, the Buick 350 has the longest stroke, which lends to making significantly more torque than any of the others. It also made the Buick 350 significantly wider - essentially the same width as the Buick big-blocks, which have the shortest stroke of the GM big-blocks. In fact, at a glance the buick 350 is commonly mistaken for the 455 engine due to the oversized intake manifold atop the engine. The Buick 350 also shares an integrated Aluminum timing cover as do most of the Buick small & big blocks that incorporates the oil pump mechanisms as well. Leaving the oil filter exposed to oncoming air for added cooling.

The Buick 350 was used in the Jeep Gladiator and Wagoneer from 1968 to 1971.

Toyota Variable Induction System,

Toyota Variable Induction System, or T-VIS, is a variable intake system designed by Toyota.

It improves the low-end torque of high-performance, small displacement four-stroke engines by changing the geometry of the intake manifold according to the engine rotation speed. The system uses two separate intake runners per cylinder, one being equipped with a butterfly valve that can either open or close the runner. All valves are attached to a common shaft which is rotated by a vacuum actuator outside the manifold.

The engine control unit allows vacuum into the actuator by powering a solenoid valve when the engine rotation speed is below 4200 rpm.Above this engine speed vacuum is cut off and a spring inside the actuator causes the butterfly valve to fully open. The theory behind the system is that in the lower speed band the velocity of the intake air can be improved because the intake runner cross section per cylinder is smaller. However, when the engine gains speed, the required air flow volume is more significant so the second runner is opened to improve the flow.

Toyota used the T-VIS system from the mid-80s to early 90s on its high-performance twincam engines, such as the 4A-GE and 3S-GE.

PRV engine

The PRV engine is an automobile petrol V6 engine that was developed jointly by Peugeot, Renault and Volvo Cars and sold from 1974 to 1998. It was gradually replaced after 1994 by another joint PSA-Renault design known as the ES engine at PSA and the L engine at Renault.


Engineering


Ignition timing

The original engineering work done on the V8 can still be seen in the resulting V6: its cylinder banks are arranged at 90° instead of the much more common 60°. V8 engines nearly universally feature 90° configurations because this allows for a natural firing order. V6 engines, on the other hand, are generally arranged at 60° (again because of timing) but can be built as 90° engines with either staggered timing or split crankshaft journals.

First-generation PRV engines (1974-1985) featured uneven ignition timing. Second generation PRV engines (introduced in 1984 in the Renault 25 Turbo) featured split crankshaft journals and even ignition timing all electronically controlled. [1] Other similar design examples are the odd-fire and even-fire Buick V6 and the Maserati V6 seen in the Citroën SM.


The ignition timing has nothing to do with the bank of the cylinders; V8s run smoothest with a 90º bank, while V6s run smoothest with a 60º bank. I do believe, however, that changing the cylinder firing order can result in a better idle quality and less vibrations. That is why the modern chevy small block v8 changed its firing order with the introduction of the LS series of engines in 1997.


Specifications

* Power (DIN): 100 kW at 92 r/s (136 hp at 5,500 rpm)
* Power (SAE): 97 kW at 92 r/s (130 hp at 5,500 rpm)
* Torque (DIN): 215 Nm at 48 r/s
* Torque (SAE): 208 Nm at 48 r/s (153 ft.lbf at 2,750 rpm)
* Compression ratio: 8.8:1
* Bore: 91 mm
* Stroke: 73 mm
* Displacement: 2,849 cm³
* Firing order: 1-6-3-5-2-4
* Weight: ~150 kg


PRV powered automobiles

The dates following each entry denote the introduction of a PRV V6-equipped model

* Alpine A310 (October 1976)
* Alpine A610 (1991)
* Alpine GT/GTA (1984)
* Citroën XM (1989)
* De Lorean DMC-12 (1981)
* Dodge Monaco (1990-1992)
* Eagle Premier (1988-1992)
* Helem V6
* Lancia Thema (1984)
* Peugeot 504 coupé/cabriolet (1974/1975)
* Peugeot 505 (July 1986)
* Peugeot 604 (March 1975)
* Peugeot 605 (1990)
* Renault 25 (1984)
* Renault 30 (March 1975)
* Renault Espace
* Renault Laguna
* Renault Safrane
* Talbot Tagora (1980)
* Venturi (all models)
* Volvo 262/264/265 (October 3, 1974)
* Volvo 760 GLE (February 1982)
* Volvo 780 (1985)


PRV engines in racing

* Alpine A310 V6
* Fouquet buggies
* Peugeot 504 V6 Coupé
* Schlesser Original
* Venturi 400GTR and 600LM
* WM Peugeot

Exhaust gas recirculation

Exhaust gas recirculation (EGR) is a NOx (nitrogen oxide and nitrogen dioxide) reduction technique used in most gasoline and diesel engines.

EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders. Intermixing the incoming air with recirculated exhaust gas dilutes the mix with inert gas, lowering the adiabatic flame temperature and (in diesel engines) reducing the amount of excess oxygen. The exhaust gas also increases the specific heat capacity of the mix lowering the peak combustion temperature. Because NOx formation progresses much faster at high temperatures, EGR serves to limit the generation of NOx. NOx is primarily formed when a mix of nitrogen and oxygen is subjected to high temperatures.


EGR in Spark-Ignited (SI) Engines

In a typical automotive SI engine, 5 to 15 percent of the exhaust gas is routed back to the intake as EGR (thus comprising 5 to 15 percent of the mixture entering the cylinders). The maximum quantity is limited by the requirement of the mixture to sustain a contiguous flame front during the combustion event; excessive EGR in an SI engine can cause misfires and partial burns. Although EGR does measurably slow combustion, this can largely be compensated for by advancing spark timing. Contrary to popular belief, a properly operating EGR actually increases the efficiency of gasoline engines via several mechanisms:

* Reduced throttling losses. The addition of inert exhaust gas into the intake system means that for a given power output, the throttle plate must be opened further, resulting in increased inlet manifold pressure and reduced throttling losses.

* Reduced heat rejection. Lowered peak combustion temperatures not only reduces NOx formation, it also reduces the loss of thermal energy to combustion chamber surfaces, leaving more available for conversion to mechanical work during the expansion stroke.

* Reduced chemical dissociation. The lower peak temperatures result in more of the released energy remaining as sensible energy near TDC, rather than being bound up (early in the expansion stroke) in the dissociation of combustion products. This effect is relatively minor compared to the first two.

It also decreases the efficiency of gasoline engines via a few more mechanisms

* Reduced intake charge density. EGR tends to heat the intake charge. This means a bigger piston or stroke must be used to induct the same amount of fuel and air mixture. This results in a bigger and heavier engine.

* Reduced specific heat ratio. A lean intake charge has a higher specific heat ratio than an EGR mixture. A reduction of specific heat ratio reduces the amount of energy that can be extracted by the piston.

EGR is typically not employed at high loads because it would reduce peak power output, and it is not employed at idle (low-speed, zero load) because it would cause unstable combustion, resulting in rough idle.


EGR in Diesel Engines

In modern diesel engines, the EGR gas is cooled through a heat exchanger to allow the introduction of a greater mass of recirculated gas. Unlike SI engines, diesels are not limited by the need for a contiguous flamefront; furthermore, since diesels always operate with excess air, they benefit from EGR rates as high as 50% (at idle, where there is otherwise a very large amount of excess air) in controlling NOx emissions.

Since diesel engines are unthrottled, EGR does not lower throttling losses in the way that it does for SI engines (see above). However, exhaust gas (largely carbon dioxide and water vapor) has a higher specific heat than air, and so it still serves to lower peak combustion temperatures; this aids the diesel engine's efficiency by reduced heat rejection and dissociation. There are trade offs however. Adding EGR to a diesel reduces the specific heat ratio of the combustion gases in the power stroke. This reduces the amount of power that can be extracted by the piston. EGR also tends to reduce the amount of fuel burned in the power stroke. This is evident by the increase in particulate emissions that corresponds to an increase in EGR. Particulate matter (mainly carbon) that is not burned in the power stroke is wasted energy. Stricter regulations on particulate matter(PM) call for further emission controls to be introduced to compensate for the PM emissions introduced by EGR. The most common is particulate filters in the exhaust system that result in reduce fuel efficiency. Since EGR increases the amount of PM that must be dealt with and reduces the exhaust gas temperatures and available oxygen these filters need to function properly to burn off soot, automakers have had to consider injecting fuel and air directly into the exhaust system to keep these filters from plugging up.


Implementation of EGR

Recirculation is usually achieved by piping a route from the exhaust manifold to the inlet manifold, which is called external EGR. A control valve (EGR Valve) within the circuit regulates and times the gas flow. Some engine designs perform EGR by trapping exhaust gas within the cylinder by not fully expelling it during the exhaust stroke, which is called internal EGR. A form of internal EGR is used in the rotary Atkinson cycle engine.

EGR can also be used by using a variable geometry turbocharger (VGT) which uses variable inlet guide vanes to build sufficient backpressure in the exhaust manifold. For EGR to flow, a pressure difference is required across the intake and exhaust manifold and this is created by the VGT.

Other methods that have been experimented with are using a throttle in a turbocharged diesel engine to decrease the intake pressure to initiate EGR flow.

Early EGR systems were relatively unsophisticated, utilizing manifold vacuum as the only input to an on/off EGR valve; reduced performance and/or drivability were common side-effects. However, modern systems utilizing electronic engine control computers, multiple control inputs, and servo-driven EGR valves typically improve performance/efficiency with no impact on drivability. In the past, a meaningful fraction of car owners disconnected their EGR systems. Some still do either because they believe EGR reduces power output, causes a build-up in the intake manifold in diesel engines, or because they feel the environmental intentions of EGR are misguided. Disconnecting an EGR system is usually as simple as unplugging an electrically operated valve or inserting a ball bearing into the vacuum line in a vacuum-operated EGR valve. In all cases, the EGR system will need to be operating normally in order to pass emissions tests.

Electronic throttle control

Electronic throttle control (ETC) is an automobile technology which severs the mechanical link between the accelerator pedal and the throttle. Most automobiles already use a throttle position sensor (TPS) to provide input to traction control, antilock brakes, fuel injection, and other systems, but use a bowden cable to directly connect the pedal with the throttle. An ETC-equipped vehicle has no such cable. Instead, the electronic control unit (ECU) determines the required throttle position by calculations from data measured by other sensors such as an accelerator pedal position sensor, engine speed sensor, vehicle speed sensor etc. The electric motor within the ETC is then driven to the required position via a closed-loop control algorithm within the ECU.

The benefits of ETC are largely unnoticed by most drivers because the aim is to make the vehicle power-train characteristics seamlessly consistent irrespective of prevailing conditions, such as engine temperature, altitude, accessory loads etc. The ETC is also working 'behind the scenes' to dramatically improve the ease with which the driver can execute gear changes and deal with the dramatic torque changes associated with rapid accelerations and decelerations.

Contrary to popular belief, except in concert with other technologies such as gasoline direct injection, ETC provides only a very limited benefit in areas such as air-fuel ratio control, exhaust emissions and fuel consumption reduction. ETC however makes it much easier to integrate features to the vehicle such as cruise control, traction control, stability control and others that require torque management, since the throttle can be moved irrespective of the position of the driver's accelerator pedal. A criticism of the very early ETC implementations was that they were "overruling" driver decisions. Nowadays, the vast majority of drivers have no idea how much intervention is happening.

Much of the engineering involved with drive-by-wire technologies including ETC deals with failure and fault management. Most ETC systems have sensor and controller redundancy, even as complex as independent microprocessors with independently written software within a control module whose calculations are compared to check for possible errors and faults.

Anti-lock braking (ABS) is a similar safety critical technology, whilst not completely 'by-wire', it has the ability to electronically intervene contrary to the driver's demand. Such technology has recently been extended to other vehicle systems to include features like brake assist and electronic steering control, but these systems are much less common, also requiring careful design to ensure appropriate back-up and fail-safe modes.

As of 2005, the Toyota Prius is the most prominent example of drive-by-wire technology, featuring electronic throttle, brake and transmission control. This is largely by necessity of the Hybrid Synergy Drive system, which assigns complete engine control and regenerative/friction braking decisions to a hybrid control computer. Further extending the drive-by-wire concept, in Europe and Japan automatic parking assist is also available — the car can control the steering to guide itself backwards into a parking space.

Some fanciful theories and applications abound as to what the ultimate implications of drive-by-wire technology might be. It has been suggested that drive-by-wire might allow a car to become completely separate from its controls, meaning that a car of the future might theoretically be controlled by any number of different control systems: push buttons, joysticks, steering wheels, or even voice commands — whatever device that designers could come up with. (This would have many advantages, such as increased flexibility for handicapped or disabled drivers.) Coupled with fuel cell applications, futuristic designs for such a car have been proposed, including a car whose entire functional driving components are concentrated in its chassis — the actual 'shell' of the car being a module that can be swapped out and replaced with different models as the driver dictates. Competitors in the DARPA Grand Challenge, an automated driving competition, relied on 100% drive-by-wire systems, in some cases including a steer-by-wire system provided by the manufacturer.

Modern Tuning Makes Maximizing Performance Much Faster

Putting some extra ponies into your daily motoring used to take entire days, cost hundreds of dollars in parts, and usually cause the loss of three or four knuckles. Not so in today’s computer-controlled vehicles, where tuning is about as easy as playing Tetris on a Game Boy. Let’s take a look at performance chips and programmers and how they’ve changed vehicle tuning.

Chances are you’ve seen the Saturday afternoon show geared toward squeezing every droplet of power out of a 50s or 60s classic. You know—the one hosted by two middle-aged guys, one with a toupee that may as well have “this is a toupee” painted on it. They spend the entire half-hour show with a bunch of time-lapsed shots taken of them tearing the engine apart to put in highly-specialized, insanely expensive parts. Once the project’s done, they fire-up the dyno and laud the 3hp gain they received for about 4 hours of total work. If you’re like me, that’s not exactly how you want to spend a weekend, all for 3hp that you may not even notice with your rear-o-meter.

Fortunately, you’re probably also driving a computer-controlled vehicle, like most of the ones sold for the last 25 years or so. That makes tuning much easier, because a set of programming determines the way your engine performs. Replace the programming with a set geared toward performance, and you have near-instant power gains. Don’t get me wrong—there’s a lot to be said for the virtues of a computer-free classic that you have full control over. But, when it comes to getting more power in just a few minutes time without ripping your hands to shreds or spending thousands on obscure parts, a computer-controlled vehicle has a distinct advantage.

How can you make these changes in minutes? With a power programmer or performance chip, like the ones made by Hypertech or Diablosport. These programmers are built to hold performance settings tested by experienced pros for your specific engine. All you have to do is plug it into the OBD-II port beneath your steering column. With simple yes or no commands, you can adjust how you want your engine to perform, upload the new programming, and you’re ready to rock with 25hp or more extra. The maximum time this will take to complete: just 10 minutes.

Many drivers who want the extra power are leery of this tuning method. “How can so much power be had so fast, when the TV pros spend hours to get few gains?” they ask. The answer is that automakers down-tune their cars for the masses. Engines are setup to work the same for you, the budding performance enthusiast, as they are for the elderly, who like to travel half the speed limit or through the occasional farmer’s market. You aren’t the average driver, and performance programmers aren’t average settings. It’s a perfect match for you; it’s not a perfect match for your mother.

Some drivers worry about warranty when they’re considering a performance programmer. Not only to the companies that make programmers take safety into account with their settings, they often give you ways to return to stock settings for service visits at the dealership. And, as with all performance mods, you’re protected by the Magnuson-Moss Warranty Act, a federal law that basically states that your vehicle’s warranty can’t be voided by mods unless the mods can be proven as the source of trouble. In other words, there’s no reason to wait—the true potential is waiting to be unlocked, and you can do it without breaking a sweat.

Toyota Prius Review

Concept vehicles are big in the world of cars. The Toyota Prius has the distinction of being the worlds cleanest and planet friendly vehicle. It has been given the honor of being the 2006 European Car of the year because of the standards that it set for manufactures when building their hybrid cars. Consumer Reports even reported that the Toyota Prius came in with a 94 percent owner satisfaction rating. Most of the current owners of a Prius would definitely purchase another one again, thus making Consumer Reports rate it as the most satisfying vehicles on the road.

So Just what make the Prius a step above the rest? The Toyota Prius is an astonishing Hybrid. The way Toyota uses technology is quite amazing. Instead of just turning a key to start the ignition, the Toyota Prius is started by pressing a round ?Power? button on the dash board. Toyota has incorporated an interactive touch sensitive multi-informational display screen that is mounted on the center console. This display screen has many functions from showing you fuel consumption, radio settings, climate control, and many other functions that are occurring within the vehicle.

The Toyota Prius carries a rating of Advanced Technology Partial Zero Emission Vehicle, making it the cleanest emission production car on the road today. The Prius boasts an average of 90 percent more cleaner air than the average car on the road today. It employs the Hybrid Synergy Drive technology making it the leading vehicle in the industry of Hybrid technology. It offers a seamless integration of gas engine and emissions free electric motor allowing it to achieve amazing fuel economy. This makes it the best choice for the environment and the consumer.

Hybrids have become more and more popular in the world because of its dramatically increased fuel efficiency; especially with the rising cost of gas prices all over the world. People tend to flock to cars that will give them the most bang for their buck and are environmentally friendly. This make the Toyota Prius the most environmentally friendly care on the road today and thus, will be a good choice for you, your family, and the environment.

GM X platform

There have been two X-body automobile platforms from General Motors. All X-bodies were small entry-level models.


Rear wheel drive

The rear-wheel drive X-body underpinned the Chevrolet Nova and similar cars of the late 1960s and 1970s. It was also the basis for the Cadillac Seville's K platform. The wheelbase was 111 in and many components were shared with the contemporary F platform.

Applications:

* Buick Apollo (1973–1974; 1975 sedan only)
* Buick Skylark (1975 coupe only; 1976–1979)
* Chevrolet Nova (1968–1979)
* Oldsmobile Omega (1973–1979)
* Pontiac Ventura (1971–1977)
* Pontiac Phoenix (1977–1979)

1968–1974 GM X-bodies were rear steer (with the steering linkage behind the engine crossmember) whereas 1975–1979 models were front steer (with the steering linkage forward of the engine crossmember.) Note: "Rear steer" does not mean that the rear wheels steered the vehicle. It strictly relates to the position of steering components in relation to the engine crossmember. No station wagons were produced on the X-body platform. (Rival Chrysler produced a station wagon based on their Dodge Aspen/Plymouth Volare compacts.)


Front wheel drive

The front-wheel drive X-body was used for compact cars from 1980 to 1985. The X-body program was widely considered a failure at the time, but the derivative GM A platform, which was introduced in 1982, continued for over a decade. Interestingly, only the Skylark name was carried over to the next generation of GM compact cars, the N-body. The Citation was succeeded by the Chevrolet Corsica on the compact L-body for 1987.

Vehicles using the X-body include:

* 1980-1984 Oldsmobile Omega
* 1980-1984 Pontiac Phoenix
* 1980-1985 Buick Skylark
* 1980-1985 Chevrolet Citation


Braking problems

NHTSA sued General Motors Corporation over the safety of their X platform family (United States v. General Motors, 841 F.2d 400 (D.C. Cir. 1988)).

The cars were initially designed to be five-passenger models, with bucket seats and lever actuated parking brakes. However, a decision was made late in the design cycle to broaden the cars' purchasing appeal by offering six-passenger models with bench seats. This necessitated a change from a parking brake lever (mounted between the seats) to a parking brake pedal. The pedal, however, did not have enough leverage to apply sufficient pressure to the rear brakes to hold the car on an incline.

Without enough time to redesign the braking system, the decision was made simply to use brake linings with a higher coefficient of friction instead, to hold the car with the pressure that could be applied through the parking brake pedal. However, this in turn had an undesirable effect; the increase in friction of the rear brakes, along with the excess forward weight distribution of a front wheel drive car, led to a tendency for the rear wheels to lock up under braking, which led to the rear of the car slewing sideways and loss of directional control and/or spinning (see oversteer).

The Court of Appeals eventually ruled against NHTSA and for GM, however, on the grounds that NHTSA's case for performance failure was based only on circumstantial evidence.

Turbos at High Altitudes

A turbocharger helps at high altitudes, where the air is less dense. Normal engines will experience reduced power at high altitudes because for each stroke of the piston, the engine will get a smaller mass of air. A turbocharged engine may also have reduced power, but the reduction will be less dramatic because the thinner air is easier for the turbocharger to pump.

Older cars with carburetors automatically increase the fuel rate to match the increased airflow going into the cylinders. Modern cars with fuel injection will also do this to a point. The fuel-injection system relies on oxygen sensors in the exhaust to determine if the air-to-fuel ratio is correct, so these systems will automatically increase the fuel flow if a turbo is added.

If a turbocharger with too much boost is added to a fuel-injected car, the system may not provide enough fuel -- either the software programmed into the controller will not allow it, or the pump and injectors are not capable of supplying it. In this case, other modifications will have to be made to get the maximum benefit from the turbocharger.

Advantages of Having a GPS Vehicle Tracking System

It seems that everywhere you look there is a GPS advertisement, and for good reason. This system, when installed in a vehicle can help you in a variety of different situations. However, while all of this technology can be a wonderful thing to have at your fingertips, knowing how to use it can be a bit overwhelming. The following information is a general guide to most GPS vehicle systems and will help you navigate through the buttons and options with ease.

Perhaps one of the most important and emotional reasons to have a GPS vehicle tracking system installed in your car is the "panic" button. This button is to be used in cases of emergency. This can include everything from a fender bender to a carjacking, what ever the reason, when this button is pushed an operator at the GPS carrier can immediately listen to what is happening. If it is safe, and there is no robbery taking place, they will talk to you and help to asses the situation. If, however, they determine that it would be detrimental to speak to you, they will contact the authorities for you.

For instance, if you, or your children, lock you out of your car, it can easily be unlocked by phoning into the call center of the service you choose. This is also a very handy feature if you tend to lose your car in a crowded parking lot, they will find it for you and send the lights flashing and the horn honking for you. Maybe the best thing about being able to call for help in these types of situations is that you don't have to actually see the grins on the faces of the people you are speaking with.

If you happen to be traveling in your car and it begins to show signs of a mechanical issue, or perhaps it completely breaks down and leaves you stranded in the middle of nowhere, you will have the peace of mind of knowing that you only have to push a button and help will be summoned. Most systems will have this particular button labeled as a "communication" button.

For many parents, this device can give them peace of mind. It gives them the ability to call and check upon the exact whereabouts of a car that is being driven by a child without directly interfering with their plans.


The most obvious reason to have a GPS vehicle tracking system is in a situation where your car is stolen. If you ever become a victim of vehicle theft and are lucky enough to have a GPS system installed all you will need to do is to inform your GPS carrier of the theft. They can track the cars' exact location and its speed, when the vehicle has been located, they will call police to recover it for you.

The advantages of having a GPS vehicle tracking system installed are numerous, but beware of what you are paying for before you sign on the dotted line. Find out exactly what options your plan covers and what the monthly service fee is. Make sure also, that your system is being installed by someone who is licensed to do so.

Gudgeon pin

The gudgeon pin is that which connects the piston to the connecting rod and provides a bearing for the connecting rod to pivot as it moves. In very early engine designs (including those driven by steam and also many very large stationary or marine engines, the gudgeon pin is located in a sliding crosshead that connects to the piston via a rod.

The gudgeon pin is typically a forged short hollow rod made of a steel alloy of high strength and hardness that may be physically separated from both the connecting rod and piston or crosshead. The design of the gudgeon pin, especially in the case of small, high-revving automotive engines is challenging. The gudgeon pin has to operate under some of the highest temperatures experienced in the engine, with difficulties in lubrication due to its location, while remaining small and light so as to fit into the piston diameter and not unduly add to the reciprocating mass. The requirements for lightness and compactness demand a small diameter rod that is subject to heavy shear and bending loads, with some of the highest pressure loadings of any bearing in the whole engine. To overcome these problems, the materials used to make the gudgeon pin and the way it is manufactured are amongst the most highly-engineered of any mechanical component found in internal combustion engines.


Design Options

Gudgeon pins use two broad design configurations: semi-floating or fully-floating. In the semi-floating configuration, the pin is usually fixed relative to the piston by an interference fit with the journal in the piston. The connecting rod small end bearing thus acts as the bearing alone. In this configuration, only the small end bearing requires a bearing surface, if any. If needed, this is provided by either electroplating the small end bearing journal with a suitable metal, or more usually by inserting a bearing sleeve into the eye of the small end, which has an interference fit with the aperture of the small end. During overhaul, it is usually possible to replace this bearing sleeve if it is badly worn. The reverse configuration that is occasionally implemented is an interference fit with the small end eye instead, with the gudgeon pin journals in the piston functioning as bearings. This arrangement is usually more difficult to manufacture and service because two bearing surfaces or inserted sleeves complicate the design. In addition, the pin must be precisely set so that the small end eye is central. Because of thermal expansion considerations, this arrangement is more usual for single-cylinder engines as opposed to multiple cylinder engines with long cylinder blocks and crankcases.

In the fully-floating configuration, a bearing surface is created both between the small end eye and gudgeon pin and the journal in the piston. No interference fit is used in any instance and the pin 'floats' entirely on bearing surfaces. The average rubbing speed of each of the three bearings is halved and the load is shared across a bearing that is usually about three times the length of the semi-floating design with an interference fit with the piston.

Manifold vacuum in cars

Most automobiles use four-stroke otto cycle engines with multiple cylinders attached to a single intake manifold. During the induction stroke, the piston descends in the cylinder and the intake valve is open. As the piston descends it effectively increases the volume in the cylinder above it, setting up low pressure. This sucks in air through the intake manifold and carburetor or fuel injection system, where it is mixed with fuel. Because multiple cylinders suck on the manifold at different times in the engine cycle, there is almost constant suction through the inlet manifold from carburetor to engine.

To control the amount fuel/air mix entering the engine, a simple butterfly valve (the throttle) is generally fitted at the start of the intake manifold (just below the carburetor in carbureted engines). The butterfly valve is simply a circular disc fitted on a spindle, fitting inside the pipe work. It is connected to the accelerator pedal of the car, and is set to be fully open when the pedal is fully depressed and fully closed when the pedal is released. The butterfly valve often contains a small "idle cutout", a hole that allows small amounts of fuel/air mixture into the engine even when the valve is fully closed.

If the engine is operating under light or no load and intermediate throttle, the throttle is closed and the engine pumps the air out of the intake manifold as fast as it can leak in through the throttle. The engine speed is limited only by the amount of fuel/air mixture that is available in the manifold. Under full throttle and light load, other effects (such as valve float, turbulence in the cylinders, or ignition timing) limit engine speed so that the manifold pressure can increase -- but in practice, parasitic drag on the internal walls of the manifold, plus the restrictive nature of the venturi at the heart of the carburetor, means that a low pressure will always be set up as the engine's internal volume exceeds the amount of the air the manifold is capable of delivering.

If the engine is operating under heavy load at wide throttle openings (such as accelerating from a stop or pulling the car up a hill) then engine speed is limited by the load and minimal vacuum will be created. Engine speed is low but the butterfly valve is fully open. Since the pistons are descending more slowly than under no load, the pressure differences are less marked and parasitic drag in the induction system is negligible. The engine pulls air into the cylinders at the full ambient pressure.

Vacuum is created in some situations. On deceleration or when descending a hill, the throttle will be closed and a low gear selected to control speed. The engine will be rotating fast due to the fact that the road wheels and transmission are moving quickly, but the butterfly valve will be fully closed. The flow of air through the engine is strongly restricted by the throttle, producing a strong vacuum on the engine side of the butterfly valve which will tend to limit the speed of the engine. This phenomenon, known as compression braking, is often used in engine braking to prevent acceleration or even to slow down with minimal or no brake usage (as when descending a long or steep hill). Note that although "compression braking" and "engine braking" are sometimes used to describe the same thing, "compression braking" here refers to the phenomenon itself while "engine braking" refers to the driver's usage of the phenomenon. Compression braking can be greatly increased by closing the exhaust with a valve on the over-run, which is often done on large trucks.


Uses of manifold vacuum

This low (or negative) pressure can be put to uses. A pressure gauge measuring the manifold pressure can be fitted to give the driver an indication of how hard the engine is working and can be used to achieve maximum momentary fuel efficiency by adjusting driving habits: minimizing manifold vacuum increases momentary efficiency. A weak manifold vacuum under closed-throttle conditions shows that the butterfly valve or internal components of the engine are worn, preventing good pumping action by the engine and reducing overall efficiency.

Vacuum is often used to drive auxiliary systems on the vehicle. Vacuum-assist brake servos, for example, use atmospheric pressure pressing against the engine manifold vacuum to increase pressure on the brakes. Since braking is nearly always accompanied by the closing of the throttle and associated high manifold vacuum, this system is simple and almost foolproof. Petrol engine 4x4 vehicles or older petrol-engine trucks used for towing sometimes have a vacuum tank fitted to allow vacuum to be available at all times to provide power to run trailer-mounted braking systems.

Some cars built before the 1960s used manifold vacuum to drive windscreen wipers via a small piston and valve arrangement connected to the wiper mechanism. This system was simple and reliable, but meant that the speed of the wipers changed often- speeding up as the car went downhill and slowing down or stopping as the car accelerated.


Manifold vacuum in diesel engines

Many diesel engines do not have butterfly valve throttles. The manifold is connected directly to the air intake and the only suction created is that caused by the descending piston with no venturi to increase it, and the engine power is controlled by varying the amount of fuel that is injected into the cylinder by a fuel injection system. This assists in making diesels much more efficient than petrol engines.

If vacuum is required (vehicles that can be fitted with both petrol and diesel engines often have systems requiring it), a butterfly valve connected to the throttle can be fitted to the manifold. This reduces efficiency and is still not as effective as it is not connected to a venturi. Since low-pressure is only created on the over-run (such as when descending hills with a closed throttle), not over a wide range of situations as in a petrol engine, a vacuum tank is fitted.

Most diesel engines now have a separate vacuum pump ("exhauster") fitted to provide vacuum at all times, at all engine speeds.

Many new BMW petrol engines do not use a throttle valve in normal running, but instead use "Valvetronic" variable-lift intake valves to control the amount of air entering the engine. Like a diesel engine, manifold vacuum is practically non-existent in these engines and an exhauster must be added to power the brake servo. Valvetronic requires very high modulus valve springs and results in a heavy valvetrain, so despite its advantages in fuel economy, it is currently unsuitable for high-revving engines.

Variable Length Intake Manifold

Variable Length Intake Manifold (VLIM) is an automobile engine manifold technology. As the name implies, VLIM can vary the length of the intake tract in order to optimize power and torque, as well as provide better fuel efficiency.

There are two main effects of variable intake geometry:

* Swirl
Variable geometry can create a beneficial air swirl pattern in the combustion chamber. The swirls help distribute the fuel and form a homogeneous air-fuel mixture which ignites without engine knocking. At low rpm, the speed of the airflow is increased by directing the air through a longer path with limited capacity (i.e., cross-sectional area), but the shorter and larger path opens when the load increases so that a greater amount of air can enter the chamber. In DOHC designs, the air paths are often connected to separate intake valves so the shorter path can be excluded by de-activating the intake valve itself.

* Pressurization
A tuned intake path can have a light pressurizing effect similar to a low-pressure supercharger due to Helmholtz resonance. However, this effect occurs only over a narrow engine speed band. A variable intake can create two or more pressurized "hot spots", increasing engine output.

Many automobile manufacturers use similar technology with different names. Another common term for this technology is Variable Resonance Induction System (VRIS).

* Audi - 2.8-liter V6 gas engine (1991-98); 3.6 and 4.2 liter V8 engines, 1987-present

* Alfa Romeo - 2.0 TwinSpark 16v - 155 ps(114 kW)

* BMW DIVA

* Ferrari - 360 Modena, 550 Maranello

* Ford DSI (Dual-Stage Intake) - on their Duratec 2.5 and 3.0 liter V6s and it was also found on the Yamaha V6 in the Taurus SHO.

* Ford - The Ford Modular V8 engines sport either the Intake Manifold Runner Control (IMRC) for 4V engines, or the Charge Motion Control Valve (CMCV) for 3V engines.

* General Motors - 3.9L LZ8/LZ9 V6, 3.2L LA3 V6

* GM Daewoo - DOHC versions of E-TEC II engines

* Honda - Integra, Legend, NSX, Prelude

* Hyundai - XG V6

* Jaguar - AJ-V6

* Lancia VIS

* Mazda VICS (Variable Intake Control System) is used in the Mazda B engine family of straight-4, and VRIS (Variable Resistance Induction System) in the Mazda K engine family of V6 engines. An updated version of this technology is employed on the new Mazda Z engine, which is also used by Ford as the Duratec.

* Mercedes-Benz

* Mitsubishi Cyclone is used on the 2.0L I4 4G63 engine family.

* Nissan I4, V6, V8

* Opel (or Vauxhall) TwinPort - modern versions of Ecotec Family 1 and Ecotec Family 0 straight-4 engines; a similar technology is used in 3.2 L 54° V6 engine

* Peugeot 2.2 L I4, 3.0 L V6

* Porsche VarioRam - 964, 993, 996, Boxster

* Proton - Campro CPS and VIM (still under testing)

* Renault - Clio 2.0RS

* Toyota T-VIS - (Toyota Variable Induction System) used in the early versions of the 3S-GE and 4A-GE families.

* Volkswagen - 1.6 L I4, VR6, W8

* Volvo - VVIS (Volvo Variable Induction System) Volvo_B52_engine as found on the Volvo_850 and S70/V70 vehicles, and their successors. Longer inlet ducts used between 1500 and 4100 RPM at 80% load or higher.

Electronic Stability Control

You are looking for just the right type and kind of parts and accessories that you would like to add to your vehicle. You simply cannot afford to purchase a new vehicle that is why you have decided to rather replace worn out parts and add some new accessories. You have been scouring the market and you have trimmed down your list to a couple of Accel wires, a Catco converter, and a Gibson Exhaust. But did you ever consider adding a feature like the Electronic Stability Control, or the ESC?

Continental Teves has got an ESC that they are currently offering the market. Their Electronic Stability Control is what they define as ?a stability enhancement system designed to electronically detect and assist drivers in critical driving situations and under adverse conditions.? What the Continental Teves ESC also boasts is that it actually does this automatically. So that means that the driver of the vehicle equipped with the ESC would be assisted by the ESC even without sending out commands to the vehicle.

So you may now ask, what exactly are the advantages that you get if you have the ESC installed in your vehicle? Well, you can actually say that this really good feature continuously compares the intended course of the driver with the actual course and direction that the vehicle is taking. And if there are disparities or differences between the two, the ESC is the one who is responsible for compensating and making up for the difference. Along with that, the ESC is the one very much responsible for keeping your vehicle on the road and on the side of safety during situations where the vehicle may actually be veering out of control. The ESC senses situations like wheel lock ups and spins as well as total loss of control of the vehicle. And when it does, the feature would make sure that the vehicle would still be on the safe side and not headed into danger.

6L80 RWD six-speed

The Hydra-Matic 6L80 six-speed automatic transmission was the first of four variants in the rear-wheel drive transmission family designed with modular flexibility and compatibility with advanced electronic controls. It also features clutch-to-clutch operation, manual range selection and an integrated 32-bit electro-hydraulic controller. It debuted in 2006 on the Cadillac XLR-V, STS-V and Chevrolet Corvette, where it is offered with paddle-shift control.

The 6L80 also is tailored for the heavy-duty requirements of SUVs and trucks, and is offered on GM’s 2007 full-size SUVs equipped with the Vortec 6.2L V-8, such as the GMC Yukon Denali and Cadillac Escalade. In all applications, the 6L80 has a wide, 6.04:1 overall ratio – including two overdrive gears – that helps deliver up to 7 percent improved 0 – 60 mph performance and up to 4 percent improved fuel economy.

The 6L80’s six forward gears have smaller “steps” between them, which bolsters both performance and the feeling of smoothness. The smaller steps also enable a steep, 4.02:1 first gear, which provides an improved-performance launch feel. And with two overdrive gears, engine rpm is reduced by approximately 9 percent at 60 mph – a reduction of about 1,350 rpm.

A 32-bit electro-hydraulic control module optimizes transmission performance according to a variety of vehicle inputs, while also enabling features including tow/haul mode, auto grade braking and manual range selection. The controller is integrated within the transmission.

Tow/haul mode is a driver-selectable feature of the 6L80 that reduces shift busyness when towing or hauling a heavy load. The feature is complemented by manual range selection, which allows the driver to block out upper gears and select desired gears for unique driving conditions, such as towing on a steep grade. The manual range selection feature increases the feeling of control by holding the gear pre-selected by the driver. Electronic safeguards prevent the transmission from being shifted in a manner that could cause engine damage or loss of vehicle control. Auto grade braking is available when the tow/haul mode is selected and the transmission is not in the range selection mode.

6L50 RWD and AWD six-speed

Hydra-Matic 6L50 six-speed transmission debuts in certain 2007 Cadillac STS rear- and all-wheel drive performance sedans and the V-8-powered SRX crossover SUV. The 6L50 is the second model of four new variants in the RWD six-speed transmission family. The 6L50 is designed with the same modular flexibility as the larger 6L80 and is fully compatible by using the same advanced electronic controls. As with the 6L80, the 6L50’s gearset configuration enables the same 6.04 wide overall ratio.

As with other GM six-speeds, the 6L50 delivers smaller steps between gears, enabling the vehicle to quickly find the best gear. A higher numerical first gear delivers strong acceleration from a standstill and two overdrive gears enable improved fuel economy through lower engine rpms at cruising speed. Also, the lower rpm achieved with the sixth gear reduces engine noise and vibration on the highway.

The 6L50 also uses the Driver Shift Control feature, which allows the driver to shift the transmission like a clutchless manual gearbox. Also, the transmission is calibrated to override the automatic gear selection during closed-throttle, high-lateral acceleration maneuvers, rapidly downshifting with nearly synchronous engine speed matching for quick power-up when the throttle is reopened. This gives the feel of a manual transmission during deceleration. Electronic safeguards prevent over-revving.

6T70 and 6T75 FWD transmissions

The Hydra-Matic 6T70 and 6T75 six-speed automatics are advanced transmissions with clutch-to-clutch shift operation for front- and all-wheel drive vehicles. The transmissions are based on a common design, with the 6T75 rated for higher torque capacity. The 6T70 debuts on the Saturn Aura and on a Pontiac G6 model; the 6T75 will be offered on the Saturn Outlook

The 6T70/75’s clutch-to-clutch operation and 6.04:1 overall ratio help the transmission deliver both performance and fuel economy, enabling up to 7 percent improved performance and up to 4 percent improved fuel economy when compared with current front-wheel drive four-speed automatics. Both transmissions use a very high numerical 4.48:1 first gear, which helps deliver exceptional launch feel, and a 0.74:1 overdrive sixth gear, which reduces engine rpms at high speeds, thereby reducing engine noise and vibrations. Fifth gear is 1:1 direct drive.

With its wide ratio and strong capacity, the 6T70/75 has the capability to transfer more torque to the drive wheels, particularly in all-wheel drive applications. It also helps vehicles, such as crossovers like the Outlook, to feel even livelier at lower speeds, particularly at launch or when pulling away from a stoplight.

The 6T70/75 offers the capability of driver shift control (DSC), which allows the driver to use tap-up/tap-down shifting to select the desired gear for specific road conditions, such as driving up a steep hill. A sophisticated transmission electro-hydraulic control module (TEHCM) is mounted inside the 6T70 and 6T75, reducing vehicle complexity. Similar to the control system used in the six-speed Hydra-Matic rear-wheel drive transmissions, the TEHCM offers improved quality through its hard-wired connections. The unit is located entirely within the transmission and operates while bathed in transmission fluid. Locating the controller internally facilitates the modular design and assembly strategy while also shielding the unit from the outside environment.

The 6T70/75 was co-developed with Ford Motor Co. Co-development of the transmission allowed it to reach production in less time and enabled each company to reduce development costs by as much as 50 percent. A common on-axis design and many common components are shared between GM and Ford Motor Co. The controls, calibrations and operation of the transmissions are unique to each company.

GM 6L50 transmission

The 6L50 (and similar 6L45) is a 6-speed longitudinally-mounted automatic transmission produced by General Motors. It is very similar in design to the larger 6L80/6L90, and will be produced at the GM Powertrain plant in Strasbourg, France. It will debut for the 2007 model year on the V8-powered versions of the Cadillac STS sedan and Cadillac SRX crossover, and will eventually replace the 5L40-E and 5L50 in GM's lineup.

The 6L50 is adaptable to rear-wheel drive and all-wheel drive applications. It can accommodate engines with up to 332 ft·lbf (450 N·m) of torque, and vehicles with a GVWR of 5,000 lb (2,268 kg).

Gear ratios:
1 4.06
2 2.37
3 1.55
4 1.16
5 0.85
6 0.67
R 3.20


Applications:

* 2008- Cadillac CTS
* 2007- Cadillac SRX
* 2007- Cadillac STS
* 2007 BMW X3 3.0
* 2007 BMW X5 3.0
* 2007 BMW 328 coupe

F20 manual transmission

The F20 manual transmission was fitted to many vehicles in the European General Motors production line up including the Opel Calibra. It was a 5 speed transmission with the following configuration:

Clutch Diameter 9.0 inches
1st Gear Ratio 3.55:1
2nd Gear Ratio 2.16:1
3rd Gear Ratio 1.48:1
4th Gear Ratio 1.13:1
5th Gear Ratio 0.89:1
Reverse Gear Ratio 3.33:1
Final Drive Ratio 3.55:1

There have been many references to the numbering designation that Vauxhall elected to utilse for gearboxes, one of the more common arguments is that it refers to the lb.ft torque capacity of the gearbox, in this case being a 200 lb.ft torque limit. Other arguments include that it is simply related to the engine size (the F20 gearbox was often fitted to 2.0L engine vehicles).

As an example the F20 transmission was fitted to the Opel Calibra 2.0L models (C20XE and X20XEV engined models)

Roto Hydramatic

Roto Hydramatic (sometimes spelled Roto Hydra-Matic or Roto-Hydramatic) was an automatic transmission built by General Motors and used on some Oldsmobile and Pontiac models from 1961 to 1964. It was based on the earlier, four-speed Hydramatic, but was more compact, providing only three forward speeds plus a small torque converter in place of the Hydramatic's fluid coupling. Oldsmobile, one of the users of this transmission, called the torque converter's stator the "Accel-A-Rotor." The lightweight, aluminum-cased transmission was sometimes nicknamed the "Slim Jim."

There were two models of the Roto Hydramatic:
the lightweight Model 5, which weighed 145 lb (66 kg) and had ratios of 3.03, 1.58, and 1.00, and
the larger Model 10, which weighed 154 lb (70 kg) and had ratios of 2.93, 1.56, and 1.00.

The stator provided a maximum torque multiplication of 1.2:1. In 1961-62 the "Model 5" was used on the Opel Kapitan, Vauxhall Velox/Cresta and EK Holden. The Roto Hydramatic was cheaper and smoother than the previous Hydramatic, but its slower, softer shifts sacrificed performance for refinement. Owners discovered that it was also less durable than Hydramatic, and was prone to various mechanical problems.

The Roto Hydramatic was phased out after the 1964 model year in favor of the two-speed Jetaway and three-speed Turbo-Hydramatic. As with previous Hydramatic transmissions, auto safety experts criticized GM for the Hydramatic design which had a shift quadrant sequence of Park-Neutral-Drive-Second-Low-Reverse (P-N-D-S-L-R) due to the placement of reverse adjacent to a forward gear as opposed to the more common P-R-N-D-S-L sequence found in most other automatic transmissions at the time that placed "reverse" between "park" and "neutral", which was also incorporated in the new Turbo Hydramatic design introduced on Buicks and Cadillacs in 1964, and then other GM divisions in 1965. The Roto Hydramatic was used in all full-sized Oldsmobile models including the Dynamic 88, Super 88, Ninety-Eight and Starfire from 1961 to 1964 as well as the compact Oldsmobile F-85 from 1961 to 1963. Pontiac used the Roto Hydramatic from 1961 to 1964 on its shorter-wheelbase full-sized cars including the Catalina, Ventura and Grand Prix, but continued with the older four-speed Super Hydramatic design in the longer-wheelbase Star Chief and Bonneville models.

Hydramatic Design

The Hydramatic used a two-element fluid coupling (not a torque converter, which has at least three elements, the pump, turbine and stator) and three planetary gearsets, providing four forward speeds plus reverse. Standard ratios for the original Hydra-Matic were 3.82:1, 2.63:1, 1.45:1 and 1.00:1 in automotive applications, and 4.08:1, 2.63:1, 1.55:1 and 1.00:1 in light truck and other commercial applications. The Jetaway Hydramatic used 3.96:1, 2.55:1, 1.55:1, and 1.00:1.

A unique feature of the Hydramatic design was the manner in which the fluid coupling was interposed in the power flow. In modern automatics, all engine power passes through the torque converter and then on to the gear train. Unless the converter includes a clutch to lock the turbine to the pump, some slippage will always occur, which can have a significant negative effect on efficiency and fuel economy. This was not the case with the Hydramatic.

In first gear, power flow was through the forward planetary gear assembly (either 1.45:1 or 1.55:1 reduction, depending on the model), then the fluid coupling, followed by the rear gear assembly (2.63:1 reduction) and through the reverse gear assembly (normally locked) to the output shaft. That is, the input torus of the fluid coupling ran at a lower speed than the engine, due to the reduction of the forward gear assembly. This produced an exceptionally smooth startup because of the relatively large amount of slippage initially produced in the fluid coupling. This slippage quickly diminished as engine RPM increased.

When the transmission upshifted to second gear, the forward gear assembly locked and the input torus now ran at engine speed. This had the desirable effect of "tightening" the coupling and reducing slippage, but unfortunately also produced a somewhat abrupt shift. It wasn't at all uncommon for the vehicle to lurch forward during the 1-2 shift, especially when the throttle was wide open.

Upon shifting to third, the forward gear assembly went back into reduction and the rear gear assembly locked. Due to the manner in which the rear gear assembly was arranged, the coupling went from handling 100 percent of the engine torque to about 40 percent, with the balance being handled solely by the gear train. This greatly reduced slippage, which fact was audible by the substantial reduction that occurred in engine RPM when the shift occurred.

The shift from third to fourth gear locked the forward gear assembly, producing 1.00:1 transmission. The fluid coupling now only handled about 25 percent of the engine torque, reducing slippage to a negligible amount. The result was a remarkably efficient level of power transfer at highway speeds, something that torque converter equipped automatics could not achieve without the benefit of a converter clutch.

Many Hydramatics did not execute the 2-3 shift very well, as the shift involved the simultaneous operation of two bands and two clutches. Accurate coordination of these components was difficult to achieve, even in new transmissions. As the transmission's seals and other elastomers aged, the hydraulic control characteristics changed and the 2-3 shift would either cause a momentary flare (runup in engine speed) or tie-up (a short period where the transmission is actually in two gears at the same time), the latter often contributing to failure of the front band.

From 1939 through 1950, the reverse anchor was used to lock the reverse unit ring gear from turning by engaging external teeth machined into that ring gear. From 1951 on, a cone clutch did the same thing when oil pressure was up, and a spring loaded parking pawl was allowed to lock the same ring gear in the absence of oil pressure. This worked better as the anchor would not grind on the external teeth if that ring gear were turning (that is, unless the engine stalled as reverse was engaged). Reverse was obtained by applying torque from the front unit (band on, in reduction) through the fluid coupling to the rear unit sun gear. The planet carrier of this gearset was splined to the planet carrier of the reverse unit. The rear unit ring gear hub had a small gear machined on its end which served as the reverse unit sun gear. Because the rear unit band was not applied for reverse, the rear unit and reverse unit compounded causing the combined planet carriers to rotate opposit to the input torque and at a further reduced speed (similar to the Model T Ford reverse). The output shaft was machined onto the rear unit and reverse unit planet carriers.

Shutting off the engine caused the transmission oil pressure to fall off. If the selector lever was in reverse or moved to reverse after the engine stopped, two mechanical parts combined to provide a parking brake. The reverse unit ring gear was held stationary by the reverse anchor. The drive shaft could still turn causing the reverse unit sungear and attached rear unit ring gear to rotate at a very high speed, were it not for the fact that the rear unit ring gear band was now applied by a heavy spring. Usually, bands are applied by a servo and released by spring pressure, but in this case, the band was held off by the servo and applied by spring pressure (actually, when the engine was running, the band was applied by a combination of spring pressure assisted by oil pressure). With the engine off, this brake band acting on the rear unit ring gear had a tremendous mechanical advantage. Since the rear unit ring gear with its attached reverse unit sun gear and the reverse unit ring gear were both locked to the transmission case, the planet carriers and driveshaft could not turn. As such, it provided and effective driveshaft mounted parking brake to be used alone or supplementing the hand brake.

History of Petroleum electric hybrid vehicle

In 1898 Ferdinand Porsche designed the Lohner-Porsche carriage, a series-hybrid vehicle that broke several Austrian speed records, and also won the Exelberg Rally in 1901 with Porsche himself driving. Over 300 of the Lohner-Porsche carriages were sold to the public. As a series-hybrid, a gasoline engine powers a generator, which powered electric wheel motors. A large and heavy battery pack acted as an intermediate load-leveling device.

The 1915 Dual Power made by the Woods Motor Vehicle electric car maker had a four cylinder internal combustion engine and an electric motor. Below 15 mph (25 km/h) the electric motor alone drove the vehicle, drawing power from a battery pack, and above this speed the "main" engine cut in to take the car up to its 35 mph (55 km/h) top speed. About 600 were made up to 1918.

There have also been air engine hybrids where a small petrol engine powered a compressor. Several types of air engines also increased the range between fill-ups with up to 60% by absorbing ambient heat from its surroundings.

In 1959 the development of the first transistor-based electric car—the Henney Kilowatt—heralded the development of the electronic speed control that paved the way for modern hybrid electric cars. The Henney Kilowatt was the first modern production electric vehicle and was developed by a cooperative effort between National Union Electric Company, Henney Coachworks, Renault, and the Eureka Williams Company. Although sales of the Kilowatt were dismal, the development of the Kilowatt served was a historical "who's who" of electric propulsion technology.

A more recent working prototype of the electric-hybrid vehicle was built by Victor Wouk (one of the scientists involved with the Henney Kilowatt and also brother of author Herman Wouk ). Wouk's work with electric hybrid vehicles in the 1960s and 1970s earned him the title as the "Godfather of the Hybrid"). Wouk installed a prototype electric-hybrid drivetrain into a 1972 Buick Skylark provided by GM for the 1970 Federal Clean Car Incentive Program, but the program was killed by the EPA in 1976 while Eric Stork, the head of the EPA at the time, was accused of a prejudicial coverup[5]. Since then, hobbyists have continued to build hybrids but none was put into mass production by a major manufacturer until the waning years of the twentieth century.

The regenerative-braking hybrid, the core design concept of most production hybrids, was developed by Electrical Engineer David Arthurs around 1978 using off-the shelf components and an Opel GT. However the voltage controller to link the batteries, motor (a jet-engine starter motor), and DC generator was Mr. Arthurs'. The vehicle exhibited ~75 mpg fuel efficiency and plans for it (as well as somewhat updated versions) are still available through the Mother Earth News web site. The Mother Earth News' own 1980 version claimed nearly 84 mpg.

The Bill Clinton administration initiated the Partnership for a New Generation of Vehicles (PNGV)[6] program on September 29, 1993 that involved Chrysler, Ford, General Motors, USCAR, the DoE, and other various governmental agencies to engineer the next efficient and clean vehicle. The NRC cited automakers’ moves to produce hybrid electric vehicles as evidence that technologies developed under PNGV were being rapidly adopted on production lines, as called for under Goal 2. Based on information received from automakers, NRC reviewers questioned whether the “Big Three” would be able to move from the concept phase to cost effective, pre-production prototype vehicles by 2004, as set out in Goal 3.

The program was replaced by the hydrogen focused FreedomCAR initiative of George W. Bush's administration in 2001. The focus of the FreedomCAR initiative being to fund research too high risk for the private sector to engage in with the long term goal of developing emission / petroleum free vehicles.

In the intervening period, the widest use of hybrid technology was actually in diesel-electric locomotives. It is also used in diesel-electric submarines, which operate in essentially the same manner as hybrid electric cars. However, in this case the goal was to allow operation underwater without consuming large amounts of oxygen, rather than economizing on fuel. Since then, many submarines have moved to nuclear power, which can operate underwater indefinitely, though a number of nations continue to rely on diesel-electric fleets.

Automotive hybrid technology became successful in the 1990s when the Honda Insight and Toyota Prius became available. These vehicles have a direct linkage from the internal combustion engine to the driven wheels, so the engine can provide acceleration power. The 2000s saw development of plug-in hybrid electric vehicles (PHEVs), which can be recharged from the electrical power grid and do not require conventional fuel for short trips. The Renault Kangoo was the first production model of this design, released in France in 2003. However, the environmental benefits of plug-in hybrids depend somewhat on the source of the electrical power. In particular, electricity generated with wind would be cleaner than electricity generated with coal, the most polluting source. On the other hand, electricity generated with coal in a central power plant is still much cleaner than pure gasoline propulsion, due to the much greater efficiencies of a central plant. Furthermore, coal is only one source of centrally generated power, and in some places such as California is only a minor contributor, overshadowed by natural gas and other cleaner sources.

The Prius has been in high demand since its introduction. Newer designs have more conventional appearance and are less expensive, often appearing and performing identically to their non-hybrid counterparts while delivering 50% better fuel efficiency. The Honda Civic Hybrid appears identical to the non-hybrid version, for instance, but delivers about 50 US mpg (4.7 L/100km). The redesigned 2004 Toyota Prius improved passenger room, cargo area, and power output, while increasing energy efficiency and reducing emissions. The Honda Insight, while not matching the demand of the Prius, is still being produced and has a devoted base of owners. Honda has also released a hybrid version of the Accord.

2005 saw the first hybrid sport utility vehicle (SUV) released, Ford Motor Company's Ford Escape Hybrid. Toyota and Ford entered into a licensing agreement in March 2004 allowing Ford to use 20 patents from Toyota related to hybrid technology, although Ford's engine was independently designed and built. In exchange for the hybrid licenses, Ford licensed patents involving their European diesel engines to Toyota. Toyota announced model year 2005 hybrid versions of the Toyota Highlander and Lexus RX 400h with 4WD-i which uses a rear electric motor to power the rear wheels negating the need for a differential. Toyota also plans to add hybrid drivetrains to every model it sells in the coming decade.

For 2007 Lexus offers a hybrid version of their GS sport sedan dubbed the GS450h with "well in excess of 300hp". The 2007 Camry Hybrid becomes available starting Summer 2006 in USA and Canada. The initial batch of Camry Hybrids are built in Japan; starting October 2006, Toyota Motor Manufacturing, Kentucky (TMMK) will also produce these hybrids. Also, Nissan announced the release of the Altima hybrid (technology supplied by Toyota) around 2007.

An R.L. Polk survey of 2003 model year cars showed that hybrid car registrations in the United States rose to 43,435 cars, a 25.8% increase from 2002 numbers. California, the nation's most populous state at one-eighth of the total population, had the most hybrid cars registered: 11,425. The proportionally high number may be partially due to the state's higher gasoline prices and stricter emissions rules, which hybrids generally have little trouble passing.

Honda, which offers Insight, Civic and Accord hybrids, sold 26,773 hybrids in the first 11 months of 2004. Toyota has sold a cumulative 306,862 hybrids between 1997 and November 2004, and Honda has sold a total of 81,867 hybrids between 1999 and November 2004.

Engine balance

Engine balance is the design, construction and tuning of an engine to run smoothly. Engine balance reduces vibration and other stresses, and may improve the performance, efficiency, cost of ownership and reliability of the engine, as well as reducing the stress on other machinery and people near the engine.

These benefits are produced by:

* Reduced need for a heavy flywheel or similar devices.
* Reduced wear.
* The opportunity to reduce the size and weight of components (other than the obvious one of the flywheel) as a result of reduced stress and wear.
* Reduced vibration transmitted to the surroundings of the engine.
* The opportunity to extract more power from a given engine by:
o Higher maximum operating speeds made possible by reduced stress.
o Spreading loads equally over multiple components, for example if multiple carburetors are poorly balanced, the maximum available throttle will be reduced.

Even a single cylinder engine can be balanced in many aspects. Multiple cylinder engines offer far more opportunities for balancing, with each cylinder configuration offering its own advantages and disadvantages so far as balance is concerned.


Single cylinder engines

A single cylinder engine produces three main vibrations. In describing them we will assume that the cylinder is vertical.

Firstly, in an engine with no balancing counterweights, there would be an enormous vibration produced by the change in momentum of the piston, connecting rod and crankshaft once every revolution. Nearly all single-cylinder crankshafts incorporate balancing weights to reduce this.

While these weights can balance the crankshaft completely, they cannot completely balance the motion of the piston, for two reasons. The first reason is that the balancing weights have horizontal motion as well as vertical motion, so balancing the purely vertical motion of the piston by a crankshaft weight adds a horizontal vibration. The second reason is that, considering now the vertical motion only, the smaller piston end of the connecting rod is closer to the larger crankshaft end of the connecting rod in mid-stroke than it is at the top or bottom of the stroke, because of the connecting-rod's angle. The piston therefore travels faster in the top half of the cylinder than it does in the bottom half, while the motion of the crankshaft weights is sinusoidal. The vertical motion of the piston is therefore not quite the same as that of the balancing weight, so they can't be made to cancel out completely.

Secondly, there is a vibration produced by the change in speed and therefore kinetic energy of the piston. The crankshaft will tend to slow down as the piston speeds up and absorbs energy, and to speed up again as the piston gives up energy in slowing down at the top and bottom of the stroke. This vibration has twice the frequency of the first vibration, and absorbing it is one function of the flywheel.

Thirdly, there is a vibration produced by the fact that the engine is only producing power during the power stroke. In a four-stroke engine this vibration will have half the frequency of the first vibration, as the cylinder fires once every two revolutions. In a two-stroke engine, it will have the same frequency as the first vibration. This vibration is also absorbed by the flywheel.


Two cylinder engines

Even a two cylinder engine has three common configurations:

* Straight-twin.
* V-twin.
* Boxer twin.

Each of the three has advantages and disadvantages so far as balance is concerned.

A straight twin engine may have a simple single-throw crankshaft, with both pistons at top dead centre simultaneously. For a four-stroke engine, this gives the best possible firing sequence, with one cylinder firing per revolution, equally spaced. But it also gives the worst possible mechanical balance, no better than a single cylinder engine. Many straight twin engines therefore have an offset angle crankshaft, that is, two throws at an angle of up to 180°, with the result that the pistons reach top dead centre at different times. This produces better mechanical balance, but at the cost of uneven firing.

The first vibration noted above for the single cylinder is minimised for a crank offset angle of 180°, but balance is still far from perfect. There is still a rocking moment produced by the displacement of the cylinders one from the other, and there is still the second vibration noted for the single cylinder owing to the kinetic energy of motion of the pistons. This second vibration is minimised by a crank offset of 90°. See external links below for a detailed analysis of the effect of different crankshaft offset angles.

A "true" V-twin, like all true V engines, has only one crank throw for each pair of cylinders, so the crankshaft is a simple one like that of a single cylinder engine, and unlike any other V engine no crankshaft offset is possible. However there is still the question of the angle of the V. An angle of 90° gives a very good mechanical balance, but the firing is uneven. Smaller angles give poorer mechanical balance, but more even firing for a four-stroke (but, even less even firing for a two-stroke). Many classic V-twin motorcycles use narrow V angles as a compromise. See external links for a detailed analysis of the 90° V twin mechanical balance.

Other engines with two cylinders in a V configuration have a small offset between the cylinders in order to allow two separate crank pins, set at whatever angle the engine designer may specify in similar fashion to a straight twin. Although the characteristics of such engines are similar to those of a straight twin rather than a V, they are almost always called V engines. These engines include the Suzuki VX800 and Honda Transalp, which although called V-twins have a two-pin crankshaft, and an offset angle between the two crank throws.

The boxer engine is a type of flat engine in which each of a pair of opposing cylinders is on a separate crank throw, offset at 180° to its partner, so both cylinders of the pair reach top dead centre together. Any boxer therefore is inherently balanced so far as the momentum of the pistons is concerned, except that corresponding cylinders cannot exactly line up owing to the crankshaft design, and this produces a rocking motion. The four-stroke boxer twin has an even firing pattern, but the worst possible balance so far as the kinetic energy goes, as both pistons accelerate and deccelerate together. See external links for a detailed analysis of the boxer twin mechanical balance.


More than two cylinders

The number of possible configurations with more than two cylinders is enormous. See articles on individual configurations listed in Category:Piston engine configurations for detailed discussions of particular configurations.

There are four different forces and moments of vibration that can occur in an engine design: free forces of the first order, free forces of the second order, free moments of the first order, and free moments of the second order. The straight-6, flat-6, and V12 designs have none of these forces or moments of vibration, and hence are the naturally smoothest engine designs. (See the Bosch Automotive Handbook, Sixth Edition, pages 459-463 for details.)

Engines with particular balance advantages include:

* Straight-6
* Flat-6
* Flat-12
* V12

Engines with characteristic problems include:

* Flat-4 boxer and straight-4 have no better kinetic energy balance than a single, and require a relatively large flywheel.

* Crossplane V8, which requires a very heavily weighted crankshaft, and has unbalanced firing between the cylinder banks (producing the distinctive and much-loved V8 "burble").

* Flatplane (180° offset crankshaft) V8.

In modern multi-cylinder engines, many inherent balance problems are addressed by use of balance shafts.


Component balancing

In order to achieve the inherent balance of any engine configuration, the balancing masses must be matched. In most engines, some individual components are matched as a set. Exactly which components are matched is part of the design of the engine.

For example, pistons are often matched, and must be replaced as a set to preserve the engine balance. Less commonly, a piston may be matched to its connecting rod, the two being machined as an assembly to tighter tolerances than either alone.

Component balancing is not restricted to considerations of mechanical balance. It is vital, for example, that the compression ratio and valve timing of each cylinder should be closely matched, for optimum balance and performance. Many components affect this balance.


Carburetor balance

In engines with multiple carburetors, balancing the carburetors is a vital part of engine tuning. Imbalance will not only mean that the carburetors are operating at less than ideal, but will also unbalance the cylinders that they serve.

Internal Combustion Engine Volumetric efficiency

Volumetric efficiency in internal combustion engine design refers to the efficiency with which the engine can move the charge into and out of the cylinders. More correctly, volumetric efficiency is a ratio (or percentage) of what volume of fuel and air actually enters the cylinder during induction to the actual capacity of the cylinder under static conditions. Therefore, those engines that can create higher induction manifold pressures - above ambient - will have efficiencies greater than 100%. Volumetric efficiencies can be improved in a number of ways, but most notably the size of the valve openings compared to the volume of the cylinder and streamlining the ports. Engines with higher volumetric efficiency will generally be able to run at higher RPM, and thus power, settings as they will lose less power to moving air in and out of the engine.

There are several standard ways to improve volumetric efficiency. A common approach for manufacturers is to use a larger number of valves, see multi-valve, which cover a greater area of the cylinder head. Carefully streamlining the ports increases flow capability. This is referred to as Porting and is done with the aid of an air flow bench for testing. Today, automobile engines typically have four valves per cylinder for this reason. Many high performance cars in the 1970s used carefully arranged air intakes and "tuned" exhaust systems to "push" air into and out of the cylinders through the intrinsic resonance of the system. Two-stroke engines take this concept even further with expansion chambers that returns the escaping air-fuel mixture back to the cylinder. A more modern technique, variable valve timing, attempts to address changes in volumetric efficiency with changes in RPM of the engine -- at higher RPM the engine needs the valves open for a greater percentage of the cycle time to move the charge in and out of the engine.

More "radical" solutions include the sleeve valve design, in which the valves are replaced outright with a rotating sleeve around the piston, or alternately a rotating sleeve under the cylinder head. In this system the ports can be as large as necessary, up to that of the entire cylinder wall. However there is a practical upper limit due to the strength of the sleeve, at larger sizes the pressure inside the cylinder can "pop" the sleeve if the port is too large.

vegetable oil for fuel history

The first known use of vegetable oil as fuel for a diesel engine was a demonstration of an engine built by the Otto company and designed to burn mineral oil, which was run off of pure peanut oil at the 1900 World's Fair. When Rudolf Diesel invented the diesel engine, he designed it to run on peanut oil but it was soon discovered that it would operate on cheaper petroleum oil. In a 1912 presentation to the British Institute of Mechanical Engineers, he cited a number of efforts in this area and remarked, "The fact that fat oils from vegetable sources can be used may seem insignificant today, but such oils may perhaps become in course of time of the same importance as some natural mineral oils and the tar products are now."

Periodic petroleum shortages spurred research into vegetable oil as a diesel substitute during the 30s and 40s, and again in the 70s and early 80s when straight vegetable oil enjoyed its highest level of scientific interest. The 1970s also saw the formation of the first commercial enterprise to allow consumers to run straight vegetable oil in their automobiles, Elsbett of Germany. In the 1990s Bougainville conflict, islanders cut off from oil supplies due to a blockade used coconut oil to fuel their vehicles.

Academic research into straight vegetable oil fell off sharply in the 80s with falling petroleum prices and greater interest in biodiesel as an option that did not require extensive vehicle modifications.

What causes dieseling

The most common cause of that is the failure of the anti dieseling mechanism, sometimes an "anti dieseling solenoid", found on most late model carbureted cars. What is happening is that the throttle is remaining partially open when the engine is shut down, which gives the hot engine sufficient fuel to run without a spark from the spark plugs. Most hot engines have sufficient carbon build-up that remains glowing red hot and acts as an igniter for the fuel. The solution is to make sure that the throttle closes completely when you turn off the ignition switch. Check the throttle stop and make sure that the fast idle on the choke or the "bottom stop" isn't what is stopping the throttle from closing. It must be the anti-dieseling mechanism and that mechanism must be functional.

Some motors (Olds for example in 85) used an actual servo motor for this function. The motor drives a worm gear which advances or retracts the idle speed control rod depending on what the computer tells it to do. When it is in the "closed throttle" position and the key is killed it retracts completely to allow the throttle plate to close completely thus preventing the "dieseling" that so many cars are experiencing.

Inside Bruce Crower’s Six-Stroke Engine

Bruce Crower has lived, breathed and built hot engines his whole life. Now he’s working on a cool one—one that harnesses normally-wasted heat energy by creating steam inside the combustion chamber, and using it to boost the engine’s power output and also to control its temperature.

“I’ve been trying to think how to capture radiator losses for over 30 years,” explains the veteran camshaft grinder and race engine builder. “One morning about 18 months ago I woke up, like from a dream, and I knew immediately that I had the answer.”

Hurrying to his comprehensively-equipped home workshop in the rural hills outside San Diego, he began drawing and machining parts, and installing them in a highly modified, single-cylinder industrial powerplant, a 12-hp diesel he converted to use gasoline. He bolted that to a test frame, poured equal amounts of fuel and water into twin tanks, and pulled the starter-rope.

“My first reaction was, ‘Gulp! It runs!’” the 75-year-old inventor remembers. “And then this ‘snow’ started falling on me. I thought, ‘What hath God wrought…’”

The “snow” was flakes of white paint blasted from the ceiling by the powerful pulses of exhaust gas and steam emitted from the open exhaust stack, which pointed straight up.

Over the following year Crower undertook a methodical development program, in particular trying out numerous variations in camshaft profiles and timing as he narrowed the operating parameters of his patented six-stroke cycle.

Recently he’s been trying variations of the double-lobe exhaust cams to delay and even eliminate the opening of the exhaust valve after the first power stroke, to “recompress” the combustion gasses and thus increase the force of the steam-stroke.

The engine has yet to operate against a load on a dyno, but his testing to date encourages Crower to expect that once he gets hard numbers, the engine will show normal levels of power on substantially less fuel, and without overheating.

“It’ll run for an hour and you can literally put your hand on it. It’s warm, yeah, but it’s not scorching hot. Any conventional engine running without a water jacket or fins, you couldn’t do that.”

Indeed, the test unit has no external cooling system—no water jacket, no water pump, no radiator; nothing. It does retain fins because it came with them, but Crower indicates the engine would be more efficient if he took the trouble to grind them off. He has discarded the original cooling fan.

So far he has used only gasoline, but Bruce believes a diesel-fueled test engine he is now constructing—with a hand-made billet head incorporating the one-third-speed camshaft—will realize the true potential of his concept.

Potential…and Questions
Crower invites us to imagine a car or truck (he speaks of a Bonneville streamliner, too) free of a radiator and its associated air ducting, fan, plumbing, coolant weight, etc.

“Especially an 18-wheeler, they’ve got that massive radiator that weighs 800, 1000 pounds. Not necessary,” he asserts. “In those big trucks, they look at payload as their bread and butter. If you get 1000 lb. or more off the truck…”

Offsetting that, of course, would be the need to carry large quantities of water, and water is heavier than gasoline or diesel oil. Preliminary estimates suggest a Crower cycle engine will use roughly as many gallons of water as fuel.

And Crower feels the water should be distilled, to prevent deposits inside the system, so a supply infrastructure will have to be created. (He uses rainwater in his testing.) Keeping the water from freezing will be another challenge.

But the inventor sees overriding benefits. “Can you imagine how much fuel goes into radiator losses every day in America? A good spark-ignition engine is about 24 percent efficient; ie., about 24 cents of your gasoline dollar ends up in power. The rest goes out in heat loss through the exhaust or radiator, and in driving the water pump and the fan and other friction losses.

“A good diesel is about 30 percent efficient, a good turbo diesel about 33 percent. But you still have radiators and heavy components, and fan losses are extremely high on a big diesel truck.”

Bottom-line, Bruce estimates his new operating cycle could improve a typical engine’s fuel consumption by 40 percent. He also anticipates that exhaust emissions may be greatly reduced. It’s all thanks to the steam.

“A lot of people don’t know that water expands 1600 times when it goes from liquid into steam. Sixteen hundred! This is why steam power is so good. But it’s dangerous…”

The danger of a boiler explosion has long been a factor in engineering—and in operating—steam powerplants of all kinds, and Crower is properly wary of the miniature boiler he has conjured up inside his test engine. That’s one reason he chose to use one originally manufactured as a diesel, for its inherent strength, though he installed a carburetor and ignition system so it could burn gasoline at first.

The original diesel fuel injector system now supplies the water spray to generate the steam-stroke.

In addition to producing extra power, the injected water cools the piston and exhaust valve, which suggests to Crower that he could raise the compression ratio. “I’ve done this many times on regular engines: 15-to-1 on gasoline for the first five seconds works pretty good until you get some chamber heat and then suddenly it gets into pinging. But with the chamber being chilled, I bet 12-, 13-to-1 will be no problem on cheap fuel.

“So what we can maybe do is have fuels that aren’t quite as good…It’ll save a nickel a gallon not having to keep three grades going.”

As for his hope of lowering emissions, Bruce speculates the steam might purge “cling-on hydrocarbons” out of the combustion chamber. “This thing may turn out to be so clean that you won’t have to have a catalytic converter.

But he admits that’s unknown, saying “there’s a lot of experimenting still to be done.” Which prospect makes him smile. He thrives on this kind of challenge.
Bruce’s Background
“You’ve kinda got to be in the cam business and know the dynamics of engines,” Bruce Crower says about how the idea occurred to him. And he certainly has that background.

He was building and racing hot rods (and hot bikes), manufacturing speed equipment and operating his own speed shop in his home town of Phoenix when he was still a teen.

After moving to San Diego in the 1950s, among other exploits he dropped a Hemi into a Hudson and drove it to a 157-mph speed record at Bonneville.

Inevitably, the inventive and inexhaustible Crower built up a major equipment business in superchargers, intake manifolds, clutches and, especially, camshafts. He’s also credited with first suggesting a rear wing to Don Garlits—in 1963, three years before Jim Hall’s winged Chaparral. Bruce Crower is now in Florida’s Drag Racing Hall of Fame.

Crower actually had introduced a wing two years earlier, during practice on Jim Rathmann's 1961 Indianapolis car—five years before Jim Hall’s winged Chaparral. Bruce had been crewing at the Speedway since 1954 (Jimmy Bryan, second place), and had been part of Rathmann's 1960 victory effort. He was likewise on the winning teams in 1966 (Graham Hill) and 1967 (AJ Foyt). Three decades later, in 1998, Eddie Cheever won with Crower cams.

Bruce even produced his own complete Indy engine, a flat-8 that didn’t quite make the field in 1977 and then was rendered obsolete (due to its width) by the advent of ground-effect tunnels. But the Crower 8 and its automatic clutch did win an SAE award for innovation.

Today, Crower Cams and Equipment Company employs about 160 people in five facilities, and manufactures not only cams but crankshafts and connecting rods—including titanium rods for (unnamed) Formula One customers.

Bruce Crower can’t be called retired now, but he’s happy to let the company he founded “roll along” while he “plays with cars.” That’s how he looks at the intensive R&D work he carries out in the privacy of his 13-acre horse property near the rural community of Jamul.

One of several projects is building up Honda S2000 engines for the Midget raced by his granddaughter, Ashley Swanson. (“I think she’s on par with Danica Patrick,” says the proud grampa.)

But his prime focus is proving his six-stroke engine is as revolutionary as he believes it is. “I’ve been trying to find something wrong with the whole basic idea for almost a year,” he says, “but I think we’re going to have a very marketable item.”

Then he adds philosophically, “If it turns out to be great, fine. If it doesn’t, it’s just another year out of my life that I’ve had a lot of fun doing something.”

Improving engine performance tips

Increase displacement
- More displacement means more power because you can burn more gas during each revolution of the Car engine. You can increase displacement by making the cylinders bigger or by adding more cylinders. 12 cylinders seems to be the practical limit.

Increase the compression ratio
- Higher compression ratios produce more power, up to a point. The more you compress the air/fuel mixture, however, the more likely it is to spontaneously burst into flame (prior to the spark plug igniting it). Higher octane gasolines prevent this sort of early combustion. That is why high-performance cars generally need high octane gasoline - their engines are using higher compression ratios to get more power.

Stuff more into each cylinder
- If you can cram more air (and therefore fuel) into a cylinder of a given size, you can get more power from the cylinder (in the same way that you would by increasing the size of the cylinder). Turbo chargers and super chargers pressurize the incoming air to effectively cram more air into a cylinder.

Cool the incoming air
- Compressing air raises its temperature. You would like to have the coolest air possible in the cylinder because the hotter the air is the less it will expand when combustion takes place. Therefore many turbo charged and super charged cars have an intercooler. An intercooler is a special radiator through which the compressed air passes to cool it off before it enters the cylinder.

Let air come in more easily
- As a piston moves down in the intake stroke, air resistance can rob power from the car engine. Air resistance can be lessened dramatically by putting two intake valves in each cylinder. Some newer cars are also using polished intake manifolds to eliminate air resistance there. Bigger air filters can also improve air flow.

Let exhaust exit more easily
- If air resistance makes it hard for exhaust to exit a cylinder, it robs the engine of power. Air resistance can be lessened by adding a second exhaust valve to each cylinder (a car with 2 intake and 2 exhaust values has 4 valves per cylinder, which improves performance - when you hear a car ad tell you the car has 4 cylinders and 16 valves, what the ad is saying is that the engine has four valves per cylinder). If the exhaust pipe is too small or the muffler has a lot of air resistance then this can cause back-pressure which has the same effect. High-performance exhaust systems use headers, big tail pipes and free-flowing mufflers to eliminate back-pressure in the exhaust system. When you hear that a car has "Dual Exhaust", the goal is to improve the flow of exhaust by having two exhaust pipes instead of one.

Make everything lighter
- Lightweight parts help the car engine perform better. Each time a piston changes direction it uses up energy to stop the travel in one direction and start it in another. The lighter the piston, the less energy it takes.

Inject the fuel
- Fuel injection allows very precise metering of fuel to each cylinder. This improves performance and fuel economy.

Automobile Electric starter

The modern starter motor is a series-wound direct current electric motor with a solenoid switch (similar to a relay) mounted on it. When low-current power from the starting battery is applied to the solenoid, usually through a key-operated switch, it pushes out the drive pinion on the starter driveshaft and meshes the pinion with the ring gear on the flywheel of the engine. The solenoid also closes high-current contacts for the starter motor and it starts to run. Once the engine starts, the key-operated switch is opened, a spring in the solenoid assembly pulls the pinion gear away from the ring gear, and the starter motor stops. The starter's pinion is clutched to its driveshaft through an overrunning sprag clutch which permits the pinion to transmit drive in only one direction. In this manner, drive is transmitted through the pinion to the flywheel ring gear, but if the pinion remains engaged (as for example because the operator fails to release the key as soon as the engine starts), the pinion will spin independently of its driveshaft. This prevents the engine driving the starter, for such backdrive would cause the starter to spin so fast as to fly apart.

This overrunning-clutch pinion arrangement was phased into use beginning in the early 1960s; prior to that time, a Bendix drive was used. The Bendix system places the starter drive pinion on a helically-cut driveshaft. When the starter motor begins turning, the inertia of the drive pinion assembly causes it to ride forward on the helix and thus engage with the ring gear. When the engine starts, backdrive from the ring gear causes the drive pinion to exceed the rotative speed of the starter, at which point the drive pinion is forced back down the helical shaft and thus out of mesh with the ring gear. An intermediate development between the Bendix drive developed in the 1930s and the overrunning-clutch designs introduced in the 1960s was the Bendix Folo-Thru drive. The standard Bendix drive would disengage from the ring gear as soon as the engine fired, even if it did not actually start to run. The Folo-Thru drive contains a latching mechanism and a set of flyweights in the body of the drive unit. When the starter motor begins turning and the drive unit is forced forward on the helical shaft by inertia, it is latched into the engaged position. Once the drive unit is spun at a speed higher than that attained by the starter motor itself (i.e., it is backdriven by the running engine) will the flyweights pull radially outward, releasing the latch and permitting the overdriven drive unit to be spun out of engagement. In this manner, unwanted starter disengagement is avoided prior to a successful engine start.

Chrysler contributed materially to the modern development of the starter motor. In 1962, Chrysler introduced a starter incorporating a geartrain between the motor and the driveshaft. The motor shaft had integrally-cut gear teeth forming a drive gear which meshed with a larger adjacent driven gear to provide a gear reduction ratio of 3.75:1. This permitted the use of a higher-speed, lower-current, more compact motor while increasing cranking torque. Variants of this starter design was used on most vehicles produced by Chrysler Corporation from 1962 through 1987. Light aircraft engines also made extensive use of this starter, because its light weight offered an advantage. This starter formed the design basis for the offset gear reduction starters now employed by about half the vehicles on the road, and the conceptual basis for virtually all of them; those starters not employing offset geartrains like the Chrysler unit generally employ planetary epicyclic geartrains instead. Direct-drive starters are almost entirely obsolete due to their larger size, heavier weight and higher current requirements.

Ford also issued a nonstandard starter, a direct-drive "movable pole shoe" design that provided cost reduction rather than electrical or mechanical benefits. This type of starter eliminated the solenoid, replacing it with a moveable pole shoe and a separate starter relay. The Ford starter operated as follows:

1. The operator closed the key-operated starting switch.

2. A small electric current flowed through the starter relay coil, closing the contacts and sending a large current to the starter motor assembly.

3. One of the pole shoes, hinged at the front, linked to the starter drive, and spring-loaded away from its normal operating position, swung into position. This moved a pinion gear to engage the flywheel ring gear, and simultaneously closed a pair of heavy-duty contacts supplying current to the starter motor winding.

4. The starter motor cranked the engine until it started. An overrunning clutch in the pinion gear uncoupled the gear from the ring gear.

5. The operator released the key-operated starting switch, cutting power to the starter motor assembly.

6. A spring retracted the pole shoe, and with it, the pinion gear.

This starter was used on Ford vehicles from 1975 through 1990, when a gear-reduction unit conceptually similar to the Chrysler unit replaced it.


Pneumatic starter

Some gas turbine engines and Diesel engines, particularly on trucks, use a pneumatic self-starter. The system consists of a geared turbine, an air compressor and a pressure tank. Compressed air released from the tank is used to spin the turbine, and through a set of reduction gears, engages the ring gear on the flywheel, much like an electric starter would. The engine, once running, powers the compressor to recharge the tank.

Another method, for large diesel engines, uses additional valves in cylinder heads. Compressed air is let in the cylinders so that its pressure pushes pistons down when appropriate; at the upward piston movement, air is discharged through normal exhaust valves.

Since large trucks typically use air brakes, the system does double duty, supplying compressed air to the brake system. Pneumatic starters have the advantages of delivering high torque, mechanical simplicity and reliability. They eliminate the need for oversized, heavy storage batteries in prime mover electrical systems.


Auxiliary starter engine

A large, high power Diesel engine, such as those used in off-road heavy equipment, may have a small gasoline-powered engine attached to the side as a starter.

These were also sometimes called pony engines. On some applications, they shared the same cooling system and oil supply. As the pony engine warmed up, it circulated warm coolant and warm oil in the diesel engine. In addition to making it easier to crank, it improved the service life.

Understanding TheToyota Hybrid Synergy Drive

Hybrid Synergy Drive, (HSD) is a set of hybrid car technologies developed by Toyota and used in that company's Prius, Highlander Hybrid, Camry Hybrid, Lexus RX 400h, Lexus GS 450h, and Lexus LS600h/LS600hL automobiles. It combines the characteristics of an electric drive and a continuously variable transmission, using electricity and transistors in place of toothed gears. The Synergy Drive is a drive-by-wire system with no direct mechanical connection between the engine and the engine controls: both the gas pedal and the gearshift lever in an HSD car merely send electrical signals to a control computer.

HSD is a refinement of the original Toyota Hybrid System (THS) used in the 1997–2003 Toyota Prius. As such it is occasionally referred to as THS II. The name was changed in anticipation of its use in vehicles outside the Toyota brand (Lexus; the HSD systems used in Lexus vehicles have since been termed Lexus Hybrid Drive since 2006).

When required to classify the transmission type of an HSD vehicle (such as in standard specification lists or for regulatory purposes), Toyota describes HSD-equipped vehicles as having E-CVT (Electronically-controlled Continuously Variable Transmission).

General Motors and DaimlerChrysler's Global Hybrid Cooperation is similar in that it combines the power from a single engine and two motors. In contrast, Honda's Integrated Motor Assist uses a more traditional ICE and transmission where the flywheel is replaced with an electric motor.

Some early non-production Plug-in hybrid electric vehicle conversions have been based on the version of HSD found in the 2004 and 2005 model year Prius. Early Pba conversions by CalCars have demonstrated 10 miles of ev-only and 20 miles of double mileage mixed-mode range. A company planning to offer conversions to consumers named EDrive systems will be using Valence Li-ion batteries and have 35 miles of electric range. Both of these systems leave the existing HSD system mostly unchanged and could be similarly applied to other hybrid powertrain flavors by simply replacing the stock NiMH batteries with a higher capacity battery pack and of course a charger to refill them for about $0.03 per mile from standard household outlets. Another provider of a plug-in module for the Toyota Prius is Hymotion.


Theory of operation

HSD replaces a normal geared transmission with an electronic system. All car powertrains drive a driveshaft that turns the drive wheels of the car. Because an internal combustion engine delivers energy best only over a small range of torque and speed, the crankshaft of the engine is usually attached to a switchable gear train that matches the needed torque at the wheels to the torque that can be delivered by the engine.

HSD replaces the gear box, alternator and starter motor with a pair of electrical motor-generators, a computerized shunt system to control them, a mechanical power splitter that acts as a second differential, and a battery pack that serves as an energy reservoir. A motor-generator is a transducer that converts electricity to motion or vice-versa. The mechanical connections of the system allow the computer to convert mechanical power from the engine between three forms: extra torque at the wheels (under constant rotation speed), extra rotation speed at the wheels (under constant torque), and electricity. This achieves the benefits of a continuously variable transmission, except that the torque/speed conversion uses electricity rather than direct mechanical connection. An HSD car cannot operate without the computer and both motor-generators, though in principle it could operate while missing the gasoline engine. In practice, HSD cars can be driven a mile or two without gasoline, as an emergency measure to reach a gas station.

One of the motor-generators (MG2 in Toyota manuals; sometimes called "MG-T" for "Torque") is mounted on the driveshaft, and thus couples torque into or out of the driveshaft: feeding electricity into MG2 adds torque at the wheels. The engine end of the driveshaft has a second differential; one leg of this differential is attached to the gasoline engine and the other leg is attached to a second motor generator (MG1 in Toyota manuals; sometimes "MG-S" for "Speed"). The differential relates the rotation speed of the wheels to the rotation speeds of the engine and MG1, with MG1 used to absorb the difference between wheel and engine speed. The differential is an epicyclic gearset (also called a "power split device"); that and the two motor-generators are all contained in a single housing that is bolted to the engine. Special couplings and sensors monitor rotation speed of each shaft and the total torque on the driveshaft, for feedback to the control computer.

The drive works by shunting electrical power between the two motor generators and the battery pack to even out load on the gasoline engine. Because a power boost is available for periods of acceleration, the gasoline engine can be sized to match only the average load on the car, rather than the peak load on the car: this saves fuel because smaller engines are more power efficient. Furthermore, during normal operation the gasoline engine can be operated at its ideal speed and torque level for power, economy, or emissions, with the battery pack absorbing or supplying power as appropriate to balance the demand placed by the driver.


Phases of operation

The HSD operates in distinct phases depending on speed and demanded torque. Here are a few of them:

* Engine start: To start the engine, MG1 is fed negative voltage, so that it acts as a starter motor. The engine is forced into forward motion. Because both motor generators are sized to drive the entire car, turning the engine does not stress the motors and the conventional starter motor sound is not heard: engine start is silent. Engine start can occur when the car is stopped or moving.

* Low gear (equivalent): When accelerating at low speeds in normal operation, the engine turns much more rapidly than the wheels, but does not develop as much torque as is needed. MG1 is forced rapidly backwards, and the computer pulls electricity from MG1. The electricity is shunted to MG2, adding torque at the driveshaft, so that the drive train develops power at low speed and high torque.

* High gear (equivalent): When cruising at high speed, the engine turns more slowly than the wheels, but develops more torque than is needed. The computer pulls electricity from MG2, reducing the torque available at the wheels. The electricity is shunted to MG1, which boosts the speed of the driveshaft. Because the engine supplies mechanical energy to the whole system, conservation of energy is not violated: the power that is shunted from MG2 to MG1 is less than the total power developed by the engine, and so power is delivered to the wheels.

* Reverse gear: There is no reverse gear as in a conventional gearbox: the computer feeds negative voltage to MG2, applying negative torque to the wheels. Early models did not supply enough torque for some situations: there have been reports of early Prius owners not being able to back the car up steep hills in San Francisco. The problem has been fixed in recent models. If the battery is low, the system can simultaneously run the engine and draw power from MG1, although this will reduce available reverse torque at the wheels.

* Silent operation: At slow speeds and moderate torques the HSD can drive without running the gasoline engine at all: electricity is supplied only to MG2, allowing MG1 to rotate freely (and thus decoupling the engine from the wheels). This is popularly known as "Stealth Mode." Provided that there is enough battery power, the car can be driven in this silent mode for some miles even without gasoline.

* Neutral gear: Most jurisdictions require automotive transmissions to have a neutral gear that decouples the engine and transmission. The HSD "neutral gear" is achieved by breaking the electrical connection to both MG1 and MG2. Under this condition, MG1 is free running and no torque can be delivered to the wheels (MG1 rotates backwards when the engine rotates forward).

* Regenerative braking: by drawing power from MG2 and depositing it into the battery pack, the HSD can simulate normal compression braking while saving the power for future boost. The HSD system has a special transmission setting labelled 'B' (for Brake), that takes the place of a conventional automatic transmission's 'L' setting for engine braking on hills. If the battery is full, the system switches to conventional compression braking, drawing power from MG2 and shunting it to MG1, speeding the engine with throttle closed and so slowing the vehicle. The regenerative brakes in a HSD system absorb a significant amount of the normal braking load, so the conventional brakes on HSD vehicles are undersized compared to brakes on a conventional car of similar mass.

* Electric boost: The battery pack provides a reservoir of energy that allows the computer to match the demand on the engine to a predetermined optimal load curve, rather than operating at the torque and speed demanded by the driver and road. The computer manages the energy level stored in the battery, so as to have capacity to absorb extra energy where needed or supply extra energy to boost engine power.

* Battery charging: The HSD can charge its battery without moving the car, by running the engine and extracting electrical power from MG1. The power gets shunted into the battery, and no torque is supplied to the wheels.


Performance

The Toyota Prius has decent, but not sport-car-like, acceleration but has extremely high mileage for a mid sized four-door sedan: 45 mpg (US) is typical of brief city jaunts; 55 mpg is not uncommon, especially for extended drives (which allow the engine to warm up fully). This is about twice the fuel efficiency of a similarly equipped four-door sedan with a conventional power train. Not all of the extra efficiency of the Prius is due to the HSD system: the Atkinson cycle engine itself was also designed specifically to minimize engine drag with an offset crankshaft to minimize piston drag during the power stroke, and a unique intake system to prevent drag caused by manifold vacuum versus the normal Otto cycle in most engines.

The Highlander Hybrid (also sold as the Kluger in some countries) offers better performance compared to its non-hybrid version. The hybrid version goes from 0–60 mph in 7.2 seconds, trimming almost a second off the conventional version's time. Net hp is 268 hp compared with to the conventional 215 hp. Top speed for all Highlanders are limited to 112 mph. Typical fuel economy for the Highlander rates between 27 and 31 mpg. A conventional Highlander is rated by the EPA with 19 city, 25 highway mpg.

Ford Motor Company licensed HSD technology in 2004 and it is currently offered in an SUV, the Ford Escape, though a hybrid Ford Fusion will be released in the future. The four-cylinder hybrid Escape achieves an impressive increase in mileage, to 28–32 mpg.

There have been reports in the press of hybrid power trains not living up to fuel efficiency claims. This is due in part to the sensitivity of hybrid mileage to driving style. The mileage boost depends on using the gasoline engine as efficiently as possible, which requires:

* extended drives, especially in winter: Heating the internal cabin for the passengers runs counter to the design of the HSD. The HSD is designed to generate as little waste heat as possible. In a conventional car, this waste heat in winter is usually used to heat the internal cabin. In the Prius, running the heater will the require the engine to continue running to generate cabin-usable heat. This effect is most pronounced by turning the climate control (heater) off when at a stop when the engine is running. Normally the HSD control system will shut the engine off as it is not needed, and will not start it again until the generator reaches a maximum speed.

* moderate acceleration: Because hybrid cars can throttle back or completely shut off the engine during moderate, but not rapid, acceleration, they are more sensitive than conventional cars to driving style. Hard acceleration forces the engine into a high-power state while moderate acceleration keeps the engine in a lower power, high efficiency state (augmented by battery boost).

* gradual braking: Regenerative brakes re-use the energy of braking, but cannot absorb energy as fast as conventional brakes. Gradual braking recovers energy for re-use, boosting mileage; hard braking wastes the energy as heat, just as for a conventional car

Most HSD systems have batteries that are sized for maximal boost during a single acceleration from zero to the top speed of the vehicle; if there is more demand, the battery can be completely exhausted, so that this extra torque boost is not available. Then the system reverts to just the power available from the engine. This is a big difference in performance: an early-model Prius can achieve over 90 mph on a 6 degree upward slope, but after about 2,000 feet of altitude climb the battery is exhausted and the car can only achieve 55–60 mph on the same slope (until the battery is recharged by driving under less demanding circumstances).

Renix

Renix is an Engine Control Unit (ECU - also known as Electronic Control Unit) computer system in the AMC 4.0 liter straight 6 engines that was developed by Renault and Bendix. Production began by American Motors (AMC) with the 1987 Jeep Cherokee (XJ) models. It was preceded by the AMC Computerized Engine Control, and followed by the Mopar MPI system.

The Renix ECU has a powerful microprocessor and it was very advanced for its time. It also incorporates an engine knocking sensor that allows the computer to know if detonation is occurring, thus allowing the computer to make adaptive control by individual cylinder corrections to prevent pinging. The knock detection uses the signal from a wide bank accelerometer mounted on the cylinder head. Good signal to noise ratio is obtained primarily through angular discrimination.

The Renix computer was used through the 1990 model year. Unfortunately, the Renix system is now handicapped because there are few scan tools that can be "plugged in" to this computer for diagnosis.


History

* 1987 - the new Renix controlled 4.0 L engine was rated at 173 hp (129 kW) and 220 lb-ft (298 N·m) of torque.

* 1988 - output increased to 177 hp (132 kW) and 224 lb-ft (304 N·m) of torque, due to higher flowing fuel injectors.

* 1991 - Chrysler Corporation (then the owners of the Jeep brand) redesigned and renamed the RENIX ECU.


Other RENIX applications

* Volvo 700 series - B200K 2.0L inline-4, naturally aspirated with Renix ignition

* Renault engines

Vapour lock

Vapor lock is a problem that mostly affects gasoline-fueled internal combustion engines. It occurs when the liquid fuel changes state from liquid to vapor while still in the fuel delivery system. This disrupts the operation of the fuel pump, causing loss of feed pressure to the carburetor or fuel injection system, resulting in transient loss of power or complete stalling. Restarting the engine from this state may be difficult. The fuel can vaporize due to being heated by the engine, by the local climate or due to a lower boiling point at high altitude. In regions where higher volatility fuels are used during the winter to improve the starting of the engine, the use of "winter" fuels during the summer can cause vapor lock to occur more readily.


Causes and Incidence

Vapor lock was far more common in older petrol fuel systems incorporating a low-pressure mechanical fuel pump driven by the engine, located in the engine compartment and feeding a carburetor. Such pumps were typically located higher than the fuel tank, were directly heated by the engine and fed fuel directly to the float tank inside the carburetor. Fuel was drawn under negative pressure from the feed line, increasing the risk of a vapor lock developing between the tank and pump. A vapor lock being drawn into the fuel pump could disrupt the fuel pressure long enough for the float chamber in the carburetor to partially or completely drain, causing fuel starvation in the engine. Even temporary disruption of fuel supply into the float chamber is not ideal; most carburetors are designed to run at a fixed level of petrol in the float chamber and reducing the level will reduce the air:fuel mixture delivered.

Carburetor units may not effectively deal with fuel vapor being delivered to the float chamber. Most designs incorporate a pressure balance duct linking the top of the float chamber with either the intake to the carburetor or the outside air. Even if the pump can handle vapor locks effectively, fuel vapor entering the float chamber has to be vented. If this is done via the intake system, the mixture is, in-effect, enriched, creating a mixture control and pollution issue. If it is done by venting to the outside, the result is direct hydrocarbon pollution and an effective loss of fuel efficiency and possibly a petrol odor problem. For this reason, some fuel delivery systems allow fuel vapor to be returned to the fuel tank to be condensed back to the liquid phase. This is usually implemented by removing fuel vapor from the fuel line near the engine rather than from the float chamber. Such a system may also divert excess fuel pressure from the pump back to the tank.

Most modern engines are equipped with fuel injection, and have a high pressure electric fuel pump in the fuel tank. Moving the fuel pump to the interior of the tank helps prevent vapor lock, since the entire fuel delivery system is under high pressure and the fuel pump runs cooler than if it is located in the engine compartment. This is the primary reason that vapor lock is rare in modern fuel systems. For the same reason, some carbureted engines are retrofitted with an electric fuel pump near the fuel tank.

Other solutions to vapor lock are rerouting of the fuel lines away from heat generating components, installation of a fuel cooler or cool can, shielding of heat generating components near fuel lines, and insulation of fuel lines.

A vapor lock is more likely to develop when the vehicle is in traffic because the under-hood temperature tends to rise. A vapor lock can also develop when the engine is stopped while hot and the vehicle is parked for a short period. The fuel in the line near the engine does not move and can thus heat up sufficiently to form a vapor lock. The problem is more likely in hot weather or high altitude in either case.


Incidence with other fuels

The higher the volatility of the fuel, the more likely it is that vapor lock will occur. Historically, gasoline (petrol) was a more volatile distillate than today and was more prone to vapor lock. Conversely, fuel for diesel engines is far less volatile than petrol and thus these engines hardly ever suffer from vapor lock. However, diesel engine fuel systems are far more susceptible to air locks in their fuel lines as standard diesel fuel injection pumps rely on the fuel being non-compressible. Air locks are caused by air leaking into the fuel delivery line or from the tank rather than the fuel evaporating in them. Eliminating such air locks requires an extended period of turning over the engine using the starter motor or manually bleeding the system.

Warm air intake

A warm air intake, or WAI, is a system to decrease the amount of air going into a car for the purpose of increasing the fuel efficiency of the internal-combustion engine.

All warm air intakes operate on the principle of decreasing the air density and therefore the amount of oxygen available for combustion with fuel. Warm air from inside the engine bay is used opposed to air taken from the stock intake which may pull in colder (and more dense) air.

It is similar to a cold air intake (CAI), which significantly differs by collecting air from a colder source outside of the engine bay where the air has a higher density and therefore more oxygen.

Coffman engine starter

The Coffman engine starter (also known as a "shotgun starter") was a starting system used on many radial piston engines in aircraft and armored vehicles of the 1930s and 1940s. Most American military aircraft and tanks which used radial engines were equipped with this system. A derivation of the Coffman starter was also used on a number of jet engines, including those used on the Canberra B-57 light bomber.

The device used a blank gunpowder cartridge that, when fired, would cause the propeller to turn over and hopefully start the engine. The other systems used during the period were electric motors (such as those used in automobiles today) inertia starters (cranked either by hand or an electric motor) and compressed-air starters, which operate much like Coffman starters but are powered by pressurized tanks.

Shotgun starters are composed of a breech and a motor, which are connected by a metal line. The cartridge fits into the breech, and is triggered either electrically or mechanically. The expanding gases from the cartridge pressurize the line and cause the motor to spin and engage the starter ring on the engine, which is attached to the crankshaft.

The advantage of the cartridge system over electric starters is that the batteries of the time were weak and trouble-prone. Aircraft with electric motors often required the use of a battery cart and jumper cables, or large, heavy batteries carried in the plane. Inertia starters use a heavy wheel, usually made of brass, which is spun by a hand crank or electric motor, then the spinning wheel is made to engage the starter ring. The Coffman system weighs less.

The primary disadvantages of the shotgun starter are the need to keep a stock of cartridges, one of which is used for each attempt to start, and the short time that the motor is spun by each cartridge. Compressed-air starters, which use the same type of motor, are usually recharged by an engine-driven compressor, negating the need to carry cartridges. Hybrid systems can be made simply by adding a cartridge breech or an air tank to an existing system.

The Coffman starter was the most common brand of cartridge starters during the mid-1930s, and the name was used as a generic description. The starter became famous as a plot device in the movie "Flight of the Phoenix," when pilot James Stewart had a limited number of cartridges with which to start the makeshift aircraft's engine.

Some modern military diesels still use this device, but advances in battery technology have made shotgun starters obsolete for most uses.

Engine test stand

An engine test stand is a facility used to develop, characterize and test engines. The facility, often offered as a product to automotive OEMs, allows engine operation in different operating regimes and offers measurement of several physical variables associated with the engine operation.

A sophisticated engine test stand houses several sensors (or transducers), data acquisition features and actuators to control the engine state. The sensors would measure several physical variables of interest which typically include:

* crankshaft torque

* angular velocity of crankshaft

* intake air and fuel consumption rates, often detected using volumetric and/or gravimetric measurement methods

* air-fuel ratio for the intake mixture, often detected using an exhaust gas oxygen sensor

* environment pollutant concentrations in the exhaust gas such as carbon monoxide, different configurations of hydrocarbons and nitric oxides, sulphur dioxide, and particulate matter

* temperatures and gas pressures at several locations on the engine body such as engine oil temperature, spark plug temperature, exhaust gas temperature, intake manifold pressure

* atmospheric conditions such as temperature, pressure, humidity

Information gathered through the sensors is often processed and logged through data acquisition systems. Actuators allow for attaining a desired engine state (often characterized as a unique combination of engine torque and speed). For gasoline engines, the actuators may include an intake throttle actuator, a loading device for the engine such as an induction motor. The engine test stands are often custom-packaged considering requirements of the OEM customer. They often include a microcontroller based feedback control system with following features:

* closed-loop desired speed operation (useful towards characterization of steady-state or transient engine performance)

* closed-loop desired torque operation (useful towards emulation of in-vehicle, on-road scenarios, thereby enabling an alternate way of characterization of steady-state or transient engine performance)



Engine test stand applications

* Research and Development of engines, typically at an OEM laboratory
* Tuning of in-use engines, typically at service centers or for racing applications
* End of production line at an OEM factory


Engine testing for R&D

Research and Development activities on engines at automobile OEMs have necessitated sophisticated engine test stands. Automobile OEMs are usually interested in developing engines that meet the following three-fold objectives:

* to provide high fuel efficiency
* to improve drivability and durability
* to be in compliance to relevant emission legislation

Consequently, an R&D engine test stands allow for a full-fledged engine development exercise through measurement, control and record of several relevant engine variables.

Typical tests include ones that:

* determine fuel efficiency and drivability: torque-speed performance test under steady-state and transient conditions

* determine durability: aging tests, oil and lubrication tests

* determine compliance to relevant emission legislations: volumetric and mass emission tests over stated emission test cycles

* gain further knowledge about the engine itself: engine mapping exercise or development of multidimensional input-output maps among different engine variables. e.g. a map from intake manifold pressure and engine speed to intake air flow rate.

Brake specific fuel consumption

Brake specific fuel consumption (BSFC) is a measure of an engine's efficiency. It is the rate of fuel consumption divided by the rate of power production. BSFC is specific for the piston engine known as the reciprocating engine. The general term is specific fuel consumption (SFC). There is also thrust specific fuel consumption (TSFC) for turbine and rocket engines.


The BSFC Calculation (in metric units)

To calculate BSFC, use the formula BSFC = Fuel_rate / Power
Where:

Fuel_rate is the fuel consumption in grams per hour (g/hr)
Power is the power produced in Kilowatts where kW = w * Tq / 9549.27

w is the engine speed in rpm
Tq is the engine torque in newton meters (N·m)

Note: The Power in the BSFC calculation is not weather corrected.


The resulting units of BSFC are g/(kW·h)
The conversion between metric and U.S. units is:

BSFC_US(Lbs/(HP*Hr)) * 608.277 = BSFC_METRIC(g/(kW·h))
BSFC_METRIC(g/(kW·h)) * .001644 = BSFC_US(Lbs/(HP*Hr))


To calculate the actual efficiency of an engine requires the energy density of the fuel being used.
Different fuels have different energy densities defined by the fuels lower heating value.

Some examples of lower heating values for vehicle fuels are:

Certification gasoline = 18640 BTU/lb = .01204 kW·h/g
Regular gasoline = 18917 BTU/lb = .0122225 kW·h/g
Diesel fuel = 18500 BTU/lb = .0119531 kW·h/g


Thus a diesel engine's efficiency = 1/(BSFC*.0119531)
and a gasoline engine's efficiency = 1/(BSFC*.0122225)

A typical cycle average value of BSFC for a gasoline engine is 322 g/(kW·h). This means the average efficiency of a gasoline engine is only 25%. A reciprocating engine achieves maximum efficiency when the intake air is unthrottled and the engine speed is at around 2000 rpm. For a gasoline engine, the most efficient BSFC is around 256 g/(kW·h) or an efficiency of 32%. Efficiency is worse at other operating conditions. As you can see above, lower values of BSFC mean higher engine efficiency. Diesel engines are more efficient than gasoline engines. A diesel engine can have a BSFC as low as 199 g/(kW·h) and around 42% efficiency.
See also Fuel economy in automobiles.

Diesel engine Glow Plug

Glow plugs are used to heat the combustion chambers of some diesel engines in cold conditions to help ignition at coldstart. In the tip of the glow plug is a coil of a resistive wire or a filament which heats up when electricity is connected.

Glow plugs are required because diesel engines produce the heat needed to ignite their fuel by the compression of air in the cylinder and combustion chamber. Gasoline engines use an electric spark plug. In cold weather, and when the engine block, engine oil and cooling water are cold, the heat generated during the first revolutions of the engine is conducted away by the cold surroundings, preventing ignition. The glow plugs are switched on prior to turning over the engine to provide heat to the combustion chamber, and remain on as the engine is turned over to ignite the first charges of fuel. Once the engine is running, the glow plugs are no longer needed, although some engines run the glow plugs for between 5 and 10 seconds after starting to ensure smooth and efficient running and sometimes to keep the engine within emissions regulations (combustion efficiency is greatly reduced when the engine is very cold). During this period, the power fed to the glow plugs is greatly reduced to prevent them burning out by overheating.

-injection diesel engines are less thermally efficient due to the greater surface area of their combustion chambers and so suffer more from cold-start problems. They require longer pre-heating times than direct-injection engines, which often do not need glow plugs at all in temperate or hot climates even for a cold start.

In a typical diesel engine, the glow plugs are switched on for between 10 and 20 seconds prior to starting. Older, less efficient or worn engines may need as much as a minute (60 seconds) of pre-heating.

Large diesel engines as used in heavy construction equipment, ships and locomotives do not need glow plugs. Their cylinders are large enough so that the air in the middle of the cylinder is not in contact with the cold walls of the cylinder, and retains enough heat to allow ignition.

automotive diesel engines with electronic injection systems use various methods of altering the timing and style of the injection process to ensure reliable cold-starting. Glow plugs are fitted, but are rarely used for more than a few seconds.

Glow plug filaments must be made of materials such as platinum and iridium that are resistant both to heat and to oxidation and reduction by the burning mixture. These particular materials also have the advantage of catalytic activity, due to the relative ease with which molecules absorbed on their surfaces can react with each other. This aids or even replaces electrical heating.


Model engines

In model aircraft, and similar applications , glow plugs are used for starting as well as continuing the power cycle. The glow plug consists of a durable, mostly platinum, helically wound wire filament, within a cylindrical pocket in the plug body, exposed to the combustion chamber. A small direct current voltage (around 1.5 volts) is applied to the glow plug, the engine is then started, and the voltage is removed. The burning of the fuel/air mixture in a glow-plug model engine, which requires methanol for the glow plug to work in the first place, and sometimes with the use of nitromethane for greater power output, occurs due to the catalytic reaction of the methanol vapor to the presence of the platinum in the filament, thus causing the ignition. This keeps the plug's filament glowing hot, and allows it to ignite the next charge. Since the ignition timing is not controlled electrically, as in a spark ignition engine or by fuel injection, as in an ordinary diesel, it must be adjusted by the richness of the mixture, the ratio of nitromethane to methanol, the compression ratio, the cooling of the cylinder head, the type of glow plug, etc. A richer mixture will tend to cool the filiment and so retard ignition, slowing the engine, and a rich mixture also eases starting. After starting the engine can easily be leaned (by adjusting a needle valve in the spraybar) to obtain maximum power.

Forced induction

Forced induction is a term used to describe internal combustion engines that are not naturally aspirated. Instead, a gas compressor is added to the air intake, thereby increasing the quantity of oxygen available for combustion. This compressed air is normally referred to as Boost or charge air.


Introduction

Forced induction can be used to increase the power of an engine or its efficiency, or both, without much extra weight. The ambient air that the engine is normally ingesting enters the compressor inlet of turbocharger or supercharger that is inline along the air intake tract. This effectively increases the pressure and density of the air, which allows for a much greater percentage of oxygen per volume of air intake to be added to the air/fuel mixture. The effects are an increase to the effective capacity of the engine without an increase in physical size. The forced induction approach has the advantage that the intake pressure may be regulated according to the engine speed, thus providing power from extra capacity at high speed, but without wasting fuel at lower speeds. A Nitrous Oxide system is also a form of forced induction. A simple oxidizer is injected either directly (direct port) or by a single fogger...with fuel(wet nitrous system) or without fuel(dry nitrous system).

Two of the commonly used forced induction technologies are turbochargers and superchargers. They differ mainly in the power source for the compressor. Turbochargers are driven by the exhaust gases of the engine, whereas superchargers are driven by a geartrain or belt connected to the crankshaft of the engine.


Comparison

Strengths and weaknesses vary according to the method of forcing induction largely based upon the inherent design functions of both. A turbocharger acts as an obstacle to exhaust gases due to its placement in the exhaust system tract. A supercharger uses torque generated from the rotational mass internal to the engine through the crank pulley. A turbo relies on the volume and velocity of exhaust gases to spool, or spin the turbine wheel. The turbine wheel is connected to the compressor wheel via a common shaft. The compressor wheel compresses the intake charge increasing the charge density by a large factor. The amount of time that it takes a turbocharger to reach the onset of boost is referred to as lag. A supercharger is 'on' all of the time, meaning that it is capable of producing a linear increase of boost up until redline. It is easier to target a desired boost with a turbocharger as there are many forms of boost controllers that allow a user to adjust to desired boost fairly easily. In order to achieve desired boost with a supercharger, a larger or smaller pulley must be installed.


Intercooling

A fundamental principle to forced induction is that compressing air raises its temperature. As a result, the charge density is reduced and the cylinders receive less fresh air than the system’s boost pressure prescribes. The risk of pre-ignition or "knock" in internal combustion engines greatly increases. These drawbacks are countered by charge-air cooling, which passes the air leaving the turbocharger or supercharger through a heat exchanger typically called an intercooler. This is done by cooling the charge air with an ambient flow of either air (air-air intercoolers) or liquid (liquid to air intercoolers), the charge air density is increased and the temperature is reduced.


Alcohol/Water Injection

Additionally, alcohol injection is an effective means of cooling the charge air. Methanol is the preferred alcohol due to its elemental properties, and is normally mixed with water to prevent evaporation. Methanol is typically injected pre throttle body. Methanol, unlike nitrous oxide or forced induction itself, doesn't add more oxygen to the charge, but by its low evaporation point changes from a liquid to a gas as its introduced into the air charge. The evaporation process uses the heat from the intake charge to complete the phase change. The alcohol is also a fuel in the charge which will cause a rich condition if used in excess. Due to the lower intake temperatures and denser air charge more power is exerted from the engine. Methanol is typically used in conjunction with poor quality fuel(pump gas) in order to run higher than normal boost pressures.

Like was stated above, adding forced induction increases the amount of air an engine can use for combustion, in effect allowing more fuel to be used with the available oxygen. Further, it increases an engine's dynamic compression ratio. As compression ratio increases, so does the threat of knock and therefore the need for higher octane fuel.

Motronic

Bosch Motronic was one of the first digital engine-management systems. The idea behind it was to fully integrate and regulate all major engine system parameters, thereby enabling fuel delivery and spark timing control functions to be controlled by the same unit, in an attempt to achieve optimum efficiency, driveability and power output potential.

The early Motronic systems integrated spark timing control with existing Jetronic fuel injection systems, such as L-Jetronic, LH-Jetronic, K-Jetronic, and in some cases Mono-Jetronic. It was originally developed and first used in the BMW 7 Series, before being implemented on several Volvo and Porsche engines throughout the 1980s.

The components of the Motronic 1.x systems for the most part remained unchanged during production, although there are some differences in certain situations. The electronic control unit (ECU) receives information regarding engine speed and position, crankshaft angle, coolant temperature and throttle position.

An air flow meter is used to measure the volume of air entering the induction system, and a charge air temperature sensor monitors the temperature of the inducted air after it has passed through the turbocharger and the intercooler, in order to accurately calculate the overall air mass.

A separate constant idle speed (CIS) system monitors and regulates base idle speed, depending if an interior electrical component is in operation. A cold start (5th) injector is used to provide extra fuel enrichment during different cold-start conditions.

1. ^ 25 years of Bosch Motronic: Think tank under the bonnet, Bosch, may 2004

Wright R-3350 engine

The R-3350 Duplex-Cyclone was one of the most powerful radial aircraft engines produced in the United States. It was a twin row, supercharged, air-cooled, radial engine with 18 cylinders. Power ranged from 2,200 to over 3,700 hp (1,640 to 2,760 kW), depending on the model. First developed prior to World War II, the R-3350's design required a long time to mature before finally being used to power the B-29 Superfortress. After the war, the engine had matured sufficiently to become a major civilian airliner design, notably in its Turbo-Compound forms.

In 1927 Wright Aeronautical introduced their famous Cyclone engine, which powered a number of designs in the 1930s. After merging with Curtiss to become Curtiss-Wright in 1929, an effort was started to redesign the engine to the 1,000 hp (750 kW) class. The new Wright R-1820 Cyclone 9 first ran successfully in 1935, and would become one of the most-used aircraft engines in the 1930s and WWII.

At about the same time Pratt & Whitney had started a development of their equally famous Wasp design into a larger and much more powerful two-row design that would easily compete with this larger Cyclone. In 1935 Wright decided to follow P&W's lead, and started to develop much larger engines based on the mechanicals of the Cyclone. The result were two designs with a somewhat shorter stroke, a 14 cylinder design that would evolve into the Wright R-2600, and a much larger 18 cylinder design that became the R-3350.

The first R-3350 was run in May 1937, but proved to be rather temperamental. Continued development was slow, both due to the complex nature of the engine, as well as the R-2600 receiving considerably more attention. The R-3350 didn't fly until 1941, after the prototype Douglas XB-19 had been re-designed from the Allison V-3420 to the R-3350.

Things changed dramatically in 1940 with the introduction of a new contract by the USAAC to develop a long-range bomber capable of flying from the US to Germany with a 2,000 lb (900 kg) bomb load. Although smaller than the Bomber D designs that led to the B-19, the new designs required roughly the same sort of power. When preliminary designs were returned in the summer of 1940, three of the four designs were based on the R-3350. Suddenly the engine was seen as the future of Army aviation, and serious efforts to get the design into production started.

By 1943 the ultimate development of the new bomber program, the B-29, was flying. However the engines remained temperamental, and showed an alarming tendency to overheat. A number of changes were introduced into the aircraft production line in order to provide more cooling at low speeds, and the planes were rushed to operate in the Pacific in 1944. This proved unwise, as the overheating problems were not completely solved, and the engines had a tendency to burst into flame after takeoff.

Early versions of the R-3350 were equipped with carburetors, which led to serious problems with inadequate fuel mixture distribution. Near the end of World War II, in late 1944, the system was changed to use direct fuel injection, where fuel was injected directly into the combustion chamber. This change improved engine reliability immediately. After the war the engine became a favourite of large aircraft of all designs, most notably the Lockheed Constellation and Douglas DC-7.

Following the war, in order to better serve the civilian market, the Turbo-Compound system was developed in order to deliver better "gas milage". In these versions of the engine, three separate power recovery turbines were attached to the exhaust piping of each group of 6 cylinders, using the power not to deliver additional boost as in a normal turbocharger, but geared directly to the engine crankshaft by fluid drives in order to deliver more power. This recovered about 20% of the heat of the exhaust, (something around 500 hp) which would otherwise be wasted. This is not without cost, however, for those devices are also nicknamed "Parts Recovery Turbines" (and worse), and were another source of failures.

By this point reliability had improved, with the mean time between overhauls at 3,500 hours, and specific fuel consumption on the order of 0.4 lb/hp.hour (243 g/kWh). Engines still in use are now limited to 52 inches of manifold pressure and 2,880 HP with 100 octane fuel (100LL) instead of the 59.5 inches and 3,400 HP possible with 115/145 fuels, which are no longer available.

Whats a Stationary engine

A stationary engine is an engine whose framework does not move. It is normally used not to propel a vehicle but to drive a piece of immobile equipment such as a pump or power tool.

This article concentrates on oil-burning or internal combustion engines;
steam-powered engines are described separately in stationary steam engine.


Overview

Stationary engines come in a wide variety of sizes and use a wide variety of technologies. These include:

* Power stations of all sizes.

* Beam engines used in mills and factories before the widespread use of electric power.

* Winding engines used at mine pitheads.


Railways

In Victorian era railway engineering, many attempts were made to replace locomotives by stationary engines, on the grounds that it was inefficient to move something as large and heavy as a steam engine around. These attempts only succeeded where short distances were to be covered, where various kinds of cable railway were successful, particularly for steep inclines (where the inefficiency of moving the engine up and down a hill is particularly significant). A heroic failure was Isambard Kingdom Brunel's attempt to construct an atmospheric railway from Exeter to Plymouth in Devon, England.

Cable haulage did prove viable where the gradients were exceptionally steep, such as the 1 in 8 gradients of the Cromford and High Peak Railway opened in 1830. Cable railways generally have two tracks with loaded wagons on one track partially balanced by empty wagons on the other, to minimise fuel costs for the stationary engine.


Farms

Small stationary engines were frequently used on a farm to drive various kinds of power tools and equipment such as circular saws, pumps, and hay elevators. The engine was fitted to a wooden trolley with steel wheels so that it could be moved to where required, and was then coupled to the equipment by means of a flat belt.

The engines were usually powered by gasoline, but in some cases for economy it was possible to switch over to run on paraffin after the engine had warmed up - to achieve this required a part of the inlet tract to be heated by exhaust gases in order to vaporise the less volatile fuel. Very large stationary engines ran on a heavier type of fuel oil, but this type of engine was usually too large to be moved; typical applications were electricity generation and large-scale pumping.

Initially, such engines mirrored steam engine design in having the piston move horizontally, with the crank and valve gear exposed and employed a drip-feed total loss lubrication system. Later for safety, cleanliness and longevity the design moved towards enclosing the working parts and using sump lubrication.

The four-stroke cycle design was by far the most common, but Petter, a British manufacturer, developed a successful two-stroke cycle design.

A centripetal governor system was usually incorporated to regulate the engine's speed under varying loads. This is a simple negative feedback control system. The engine speed is sensed by a pair of weights that rotate with the crankshaft. As the speed increases, centripetal force causes the weights to move outward against the pressure of a retaining spring. This outward movement is used to restrict the engine power to limit the speed. If the engine slows down, the centrifugal force reduces and the weights are pulled inward by spring pressure, and this movement is used to increase the engine power to maintain speed under increasing load.

The governor can use one of two techniques for controlling speed. Today, most governors open and close a butterfly valve to control the amount of fuel-air mixture entering the engine. However, in earlier engines, the governor would cut off the fuel air mixture completely. These engines are often called "hit and miss" (variously called "hit or miss") because they do not fire on every available power stroke. When the engine is running above a certain rpm, the exhaust valve is held open, and the magneto is prevented from generating a spark. Once the speed drops, the governor allows the exhaust valve to close and the magneto to fire. The engine fires and speeds back up, causing the governor to keep the exhaust valve open again.

On a medium size engine such as a 6hp, the engine can be adjusted so that it only fires every 10 seconds or so when it is not under load. These engines generally drove a wide flat belt to run a firewood cutoff saw, a pump, a reciprocating log saw, etc.

Eventually such engines were rendered obsolete by the development of electrically powered tools, and by newer gasoline engines that were small and economical enough to be permanently built in to each piece of equipment.

Live steam models of stationary engines are popular among collectors and hobbyists.

Harmonic balancer

A harmonic balancer (also called crank pulley damper, torsional damper or vibration damper) is a device connected to the crankshaft of an engine to reduce torsional vibration.

Every time the cylinders fire, torque is imparted to the crankshaft. The crankshaft deflects under this torque, which sets up vibrations when the torque is released. At certain engine speeds the torques imparted by the cylinders are in synch with the vibrations in the crankshaft, which results in a phenomenon called resonance. This resonance causes stress beyond what the crankshaft can withstand, resulting in crankshaft failure.

To prevent this vibration, a harmonic balancer is attached to the front part of the crankshaft. The damper is composed of two elements: a mass and an energy dissipating element. The mass resists the acceleration of the vibration and the energy dissipating (rubber/clutch/fluid) element absorbs the vibrations.

Over time, the energy dissipating (rubber/clutch/fluid) element can deteriorate from age, heat, cold, or exposure to oil or chemicals. Unless rebuilt or replaced, this can cause the crankshaft to develop cracks, resulting in crankshaft failure.

There has been a trend at times by some "performance enthusiasts" to remove the harmonic balancers on their cars. The argument is that they aren't necessary and their mass reduces the performance of the engine. Others argue that this is not worth it, because the danger of damage to the engine from the vibrations the damper is intended to prevent is too high.

While net engine output can be increased without harmonic balancers, in professional race cars harmonic balancers are still commonly equipped, for reasons ranging from safety concerns to regulations. Almost all modern car manufacturers, even "performance" car makers and specialty tuners, include a harmonic balancer on their vehicles, and removal voids vehicle warranty.

Reverse-flow cylinder head

A reverse-flow cylinder head is a cylinder head that locates the intake and exhaust ports on the same side of the engine. The gasses can be thought to enter the cylinder-head and then change direction in order to exit the head. This is in contrast to the cross-flow cylinder-head design. This term is used for engines which have only one intake and one exhaust valve per cylinder.

The reverse-flow design is accepted to be inferior to a cross-flow design in terms of ultimate engineering potential, however, the reverse-flow design has been shown to be a more practical and economical manufacturing proposition and has similar potential in forced induction applications (where overly-large valves and "through flow" of gasses on cam overlap are not as desirable as under normally-aspirated conditions).

The real problem is that of temperature. With the exhaust ports on the same side as the intake ports, the intake air gets some of the heat, which reduces efficiency.

Why buy a Hybrid Car

1. - Gas Savings -
Hybrid cars can get up to 60 mpg (miles per gallon), due to their advanced aerodynamics, engine efficiency, tire technology (which is so different to the standard cars) just to mention some of its characteristics.

2. - Environmental Issues -
Reduced gas emissions equals less air pollution because a hybrid car has an electric motor and batteries to rely on when the gasoline engine is not in use. They can reduce smog up to 90%.

3. - Better engine efficiency -
Reducing the overall weight of the hybrid car is a way to increase its efficiency, smaller engines equals better efficiency. Another way is how the hybrid cars recharge they batteries, the hybrids battery pack never needs to be charged from an external source, every time you hit the brake, the brake system stores some of the energy to the batteries (this is known as regenerative braking). Also the batteries get recharged by the gasoline engine when necessary.

4. - Low Maintenance costs -
The electrical motor and the batteries dont require any maintenance; they have the same life span as the car itself. The gas engine doesnt require any more maintenance than any other normal car.

Autogas

Autogas is the common name for liquified petroleum gas when it is used as a fuel in internal combustion engines in vehicles. The same equipment is also used for similar engines in stationary applications such as generators.

Autogas is widely used as a "green" fuel as it decreases exhaust emissions (less 20 % CO2) . It has an octane rating (MON/RON) that is between 90 and 110 and an energy content (higher heating value—HHV) that is between 25.5 megajoules per litre (for pure propane) and 28.7 megajoules per litre (for pure butane.)

In countries where petrol is called petrol rather than gasoline, it is common for autogas to be simply referred to as gas. This can be confusing for people from countries where petrol is called gasoline, as they often use the abbreviation gas to refer to petrol. In the United States, autogas is more commonly known under the name of its primary constituent, propane.


Vehicle manufacturers

Toyota made a number of LPG engines in their 1970s M, R, and Y engine families.

Currently, a number of automobile manufacturers—Citroën, Fiat, Ford, Hyundai, General Motors (including Daewoo, Holden, Opel/Vauxhall, Saab), Peugeot, Renault, Toyota and Volvo—have OEM bi-fuel (dual fuel) models that will run equally well on both LPG and petrol. See list of LPG cars.

Vialli have OEM LPG powered scooters and LPG powered mopeds that run equally well on LPG. Ford Australia have offered an LPG-only variant of their Falcon model since 2000.

MAN AG produces LPG buses.

Countries

Autogas enjoys great popularity in Australia, The Netherlands, Italy, Serbia, Poland, Hong Kong and Korea. The former Soviet republic of Armenia may, however, be the world leader in autogas use. The Armenian transport ministry estimates as much as 20 to 30% of vehicles use autogas compared to traditional gasoline, once again due to the fact that it offers a very cheap alternative to both diesel and petrol, being less than half the price of petrol and some 40% cheaper than diesel. The recent rises in oil-derived fuels has sharply raised the difference.


Europe

The european standard is EN 589


Australia

LPG is popular in Australia, in part due to it being less than half the price of petrol in urban areas. The four major local manufacturers (Ford, Holden, Mitsubishi and Toyota) offer it in some models of their locally made large cars. All factory autogas vehicles are dual fuel vehicles, with the exception of the E-Gas Ford Falcon model, which runs on autogas only.

Autogas is especially popular with taxis, except in remote areas where transportation costs make autogas prices uncompetitive.

Whilst LPG is currently excise-free, an excise on LPG starting at 2.5 cents per litre in 2011 will be placed, which will increase incrementally to 12.5 cents per litre (as opposed to the 38 cpl excise on petrol) by 2015. This will be offset somewhat by a AU$2000 subsidy that was implemented in 2006 for private motorists to convert their cars to LPG.The subsidy does not presently apply to business vehicles or vehicles with a Gross Vehicle Mass of over 3500 kilograms but lobbyists are trying to get that changed. On top of the subsidy to be provided by the Australian federal government, the Western Australian government will also provide motorists with a AU$1000 subsidy under the long-running LPG subsidy scheme.


System types

The different autogas systems generally use the same type of filler, tanks, lines and fittings but use different components in the engine bay. Some injection systems use special tanks with circulation pumps and return lines similar to petrol fuel injection systems.

There are three basic types of autogas system. The oldest of these is the conventional converter-and-mixer system, which has existed since the 1940s and is still widely used today. The other two types are known as injection systems, but there are significant differences between the two.

A converter-mixer system uses a converter to change liquid fuel from the tank into vapour, then feeds that vapour to the mixer where it is mixed with the intake air.

Vapour phase injection systems use a converter in much the same way as with a mixer, but have a series of electrical shutoff solenoids and nozzles (collectively referred to as injectors) that are controlled by a computer. The computer works in much the same way as a petrol fuel injection computer. This allows much more accurate metering of fuel to the engine than is possible with mixers, improving economy and/or power while reducing emissions.

Liquid phase injection systems do not use a converter, but instead deliver the liquid fuel into a fuel rail in much the same manner as a petrol injection system. These systems are still very much in their infancy. Because the fuel vapourises in the intake, the air around it is cooled significantly. This increases the density of the intake air and can potentially lead to substantial increases in engine power output, to the extent that such systems are usually de-tuned to avoid damaging other parts of the engine. Liquid phase injection has the potential to achieve much better economy and power plus lower emission levels than are possible using mixers or vapour phase injectors.


System components

Filler

The fuel is transferred into a vehicle tank as liquid by connecting the bowser at the filling station to the filler fitting on the vehicle.

The type of filler used varies from country to country:

* The type used in Australia and the USA has an ACME threaded fitting onto which the bowser nozzle is screwed before the trigger is pulled to establish a seal then transfer fuel.
* The type used in other countries is the Bajonett.

The fill valve contains a check valve so that the liquid in the line between the filler and the tank(s) does not escape when the bowser nozzle is disconnected.

In installations where more than one tank is fitted, T-fittings may be used to connect the tanks to one filler so that the tanks are filled simultaneously. In some applications, more than one filler may be fitted, such as on opposite sides of the vehicle. These may be connected to separate tanks, or may be connected to the same tanks using T-fittings in the same manner as for connecting multiple tanks to one filler.


Hoses, pipes and fittings

The hose between the filler and tank(s) is called the fill hose or fill line. The hose or pipe between the tank(s) and the converter is called the service line. These both carry liquid under pressure.

The flexible hose between the converter and mixer is called the vapour hose or vapour line. This line carries vapour at low pressure and has a much larger diameter to suit.

Where the tank valves are located inside an enclosed space such as the boot of a sedan, a plastic containment hose is used to provide a gas-tight seal between the gas components and the inside of the vehicle.

Liquid hoses for LPG are specifically designed and rated for the pressures that exist in LPG systems, and are made from materials designed to be compatible with the fuel. Some hoses are made with crimped fittings, while others are made using re-usable fittings that are pressed or screwed onto the end of the hose.

Rigid sections of liquid line are usually made using copper tubing, although in some applications, steel pipes are used instead. The ends of the pipes are always double-flared and fitted with flare nuts to secure them to the fittings.

Liquid line fittings are mostly made from brass. The fittings typically adapt from a thread in a component, such as a BSP or NPT threaded hole on a tank, to an SAE flare fitting to suit the ends of pipes or hoses.


Tank

Vehicles are often fitted with only one tank, but multiple tanks are used in a some applications.

The tanks have fittings for filling, liquid outlet, emergency relief of excess pressure, fuel level gauge and sometimes a vapour outlet. These may be separate valves mounted into a series of 3 to 5 holes in a plate welded into the tank shell, or may be assembled onto a multi-valve unit which is bolted into one large hole on a boss welded into the tank shell.

Modern fill valves are usually fitted with an automatic fill limiter (AFL) to prevent overfilling. The AFL has a float arm which restricts the flow significantly but does not shut it off entirely. This is intended to cause the pressure in the line to rise enough to tell the bowser to stop pumping but not cause dangerously high pressures. Before AFLs were introduced, it was common for the filler (with integral check valve) to be screwed directly into the tank, as the operator had to open an ullage valve at the tank while filling, allowing vapour out of the top of the tank and stopping filling when liquid started coming out of the ullage valve to indicate that the tank was full. Modern tanks are not fitted with ullage valves.

The liquid outlet is usually used to supply fuel to the engine, and is usually referred to as the service valve. Modern service valves incorporate an electric shutoff solenoid. In applications using very small engines such as small generators, vapour may be withdrawn from the top of the tank instead of liquid from the bottom of the tank.

The emergency pressure relief valve in the tank is called a hydrostatic pressure relief valve. It is designed to open if the pressure in the tank is dangerously high, thus releasing some vapour to the atmosphere to reduce the pressure in the tank. The release of a small quantity of vapour reduces the pressure in the tank, which causes some of the liquid in the tank to vapourise to re-establish equilibrium between liquid and vapour. The latent heat of vapourisation causes the tank to cool, which reduces pressure even further.

The gauge sender is usually a magnetically coupled arrangement, with a float arm inside the tank rotating a magnet, which rotates an external gauge. The external gauge is usually readable directly, and most also incorporate an electronic sender to operate a fuel gauge on the dashboard.



Valves

There are a number of types of valve used in autogas systems. The most common ones are shutoff or filterlock valves, which are used to stop flow in the service line. These may be operated by vacuum or electricity. On dual-fuel systems with a petrol carburettor, a similar shutoff valve is usually fitted in the petrol line between the pump and carburettor.

Check valves are fitted in the filler and on the fill input to the fuel tank to prevent fuel flowing back the wrong way.

Service valves are fitted to the outlet from the tank to the service line. These have a tap to turn the fuel on and off. The tap is usually only closed when the tank is being worked on. In some countries, an electrical shutoff valve is built into the service valve.

Where multiple tanks are fitted, a combination of check valves and a hydrostatic relief valve are usually installed to prevent fuel from flowing from one tank to another. In Australia, there is a common assembly designed for this purpose. It is a combined twin check valve and hydrostatic relief valve assembly built in the form of a T-fitting, such that the lines from the tanks come into the sides of the valve and the outlet to the converter comes out the end. Because there is only one common brand of these valves, they are known colloquially as a Sherwood valve.


Converter

The converter (also known as vapouriser) is a device designed to change the fuel from a pressurised liquid to a vapour at around atmospheric pressure for delivery to the mixer or vapour phase injectors. Because of the refrigerant characteristic of the fuel, heat must be put into the fuel by the converter. This is usually achieved by having engine coolant circulated through a heat exchanger that transfers heat from that coolant to the LPG.

There are two distinctly different basic types of converter for use with mixer type systems. The European style of converter is a more complex device that incorporates an idle circuit and is designed to be used with a simple fixed venturi mixer. The American style of converter is a simpler design which is intended to be used with a variable venturi mixer that incorporates an idle circuit.

Engines with a low power output such as; scooters, quad bikes and generators can use a simpler type of convertor (also known as governor or regulator). These convertors are fed with fuel in vapour form. Evaporation takes place in the tank where refrigeration occours as the liquid fuel boils. The tanks large surface area exposed to the ambient air temperature combined with the low power output (fuel requirment) of the engine make this type of system viable. The refrigeration of the fuel tank is proportional to fuel demand hence this setup is only used on smaller engines. This type of convertor can either fed with vapour at tank pressure (called a 2 stage regulator) or be fed via a tank mounted reguator at a fixed reduced pressure(called a single stage regulator).


Mixer

The mixer is the device that mixes the fuel into the air flowing to the engine. The mixer incorporates a venturi designed to draw the fuel into the airflow due to the movement of the air.

Mixer type systems have existed since the 1940s and some designs have changed little over that time. Mixers are now being increasingly superceeded by injectors.


Vapour phase injectors

Most vapour phase injection systems mount the solenoids in a manifold block or injector rail, then run hoses to the nozzles, which are screwed into holes drilled and tapped into the runners of the intake manifold. There is usually one nozzle for each cylinder. Some vapour injection systems resemble petrol injection, having separate injectors that fit into the manifold or head in the same manner as petrol injectors, and are fed fuel through a fuel rail.


Liquid phase injectors

Liquid phase injectors are mounted onto the engine in a manner similar to petrol injectors, being mounted directly at the inlet manifold and fed liquid fuel from a fuel rail.


Electrical and electronic controls

The are four distinct electrical systems that may be used in autogas systems - fuel gauge sender, fuel shutoff, closed loop feedback mixture control and injection control.

In some installations, the fuel gauge sender fitted to the autogas tank is matched to the original fuel gauge in the vehicle. In others, an additional gauge is added to display the level of fuel in the autogas tank separately from the existing petrol gauge.

In most modern installations, an electronic device called a tachometric relay or safety switch is used to operate electrical shutoff solenoids. These work by sensing that the engine is running by detecting ignition pulses. Some systems use an engine oil pressure sensor instead. In all installations, there is a filterlock (consisting of a filter assembly and a vacuum or electric solenoid operated shutoff valve) located at the input to the converter. In European converters, there is also a solenoid in the converter to shut off the idle circuit. These valves are usually both connected to the output of the tachometric relay or oil pressure switch. Where solenoids are fitted to the outputs of fuel tanks, these are also connected to the output of the tachometric relay or oil pressure switch. In installations with multiple tanks, a switch or changeover relay may be fitted to allow the driver to select which tank to use fuel from. On dual-fuel systems, the switch used to change between fuels is used to turn off the tachometric relay.

Closed loop feedback systems use an electronic controller that operates in much the same way as in a petrol fuel injection systems, using an oxygen sensor to effectively measure the air/fuel mixture by measuring the oxygen content of the exhaust and control valve on the converter or in the vapour line to adjust the mixture. Mixer type systems that do not have a closed loop feedback fitted are sometimes referred to as open loop systems.

Injection systems use a computerised control system which is very similar to that used in petrol injection systems. In virtually all systems, the injection control system integrates the tachometric relay and closed loop feedback functions.


Converter-and-mixer system operation

The designs of converters and mixers are matched to each other by matching sizes and shapes of components within the two.

In European style systems, the size and shape of the venturi is designed to match the converter. In American style systems, the air valve and metering pins in the mixer are sized to match the diaphragm sizes and spring stiffnesses in the converter. In both cases, the components are matched by the manufacturers and only basic adjustments are needed during installation and tuning.

An autogas carburettor simply consists of a throttlebody and a mixer, sometimes fitted together using an adapter.

Cold start enrichment is achieved by the fact that the engine coolant is cold when the engine is cold. This causes denser vapour to be delivered to the mixer. As the engine warms up, the coolant temperature rises until the engine is at operating temperature and the mixture has leaned off to the normal running mixture. Depending on the system, the throttle may need to be held open further when the engine is cold in the same manner as with a petrol carburetor. On others, the normal mixture is intended to be somewhat lean and no cold-start throttle increase is needed. Because of the way enrichment is achieved, no additional choke butterfly is required for cold starting with LPG.

The temperature of the engine is critical to the tuning of an autogas system. The engine thermostat effectively controls the temperature of the converter, thus directly affecting the mixture. A faulty thermostat, or a thermostat of the wrong temperature range for the design of the system may not operate correctly.

The power output capacity of a system is limited by the ability of the converter to deliver a stable flow of vapour. A coolant temperature lower than intended will reduce the maximum power output possible, as will an air bubble trapped in the cooling circuit or complete loss of coolant. All converters have a limit, beyond which mixtures become unstable. Unstable mixtures typically contain tiny droplets of liquid fuel that were not heated enough in the converter and will vapourise in the mixer or intake to form an excessively rich mixture. When this occurs, the mixture will become so rich that the engine will flood and stall. Because the outside of the converter will be at or below zero degrees Celsius when this happens, water vapour from the air will freeze onto the outside of the converter, forming an icy white layer. Some converters are very suceptible to cracking when this happens.


Performance

The Yellow-Checker-Star taxi fleet of Las Vegas, NV is a well known propane user. These taxis are mostly production gasoline Crown Victoria conversions. When the larger propane fuel tank replaces the smaller gasoline tank, about 1/8 of the trunk space is lost. Maximum distance varies between 250 to 320 miles on one full tank. Fuel capacity varies a great deal with ambient temperature. In the coldest desert winter nights taxis might travel up to 400 miles or more. But in the hotest summer days taxis might achieve only 180 miles. When it is very hot, refueling requires extra time. This can cause long lines to form at refueling stations, particularly during shift changes.

It's a common rule of thumb in Australia that a dual fuel car will use about 20-30% more fuel than an equivalent petrol car, and has about 20-30% less power. Modern injection systems are making the gap smaller, however, as do dedicated LPG systems, since they don't have to be able to run both LPG and petrol.


LPG injection for diesel vehicles

The performance, economy and emission profile of diesel engines can be improved by injecting a small quantity of LPG into the inlet manifold. It is claimed that the LPG increases the burning efficiency of the diesel fuel from typically 75-85%, to 95-98%.

The systems typically operate by metering a small quantity of LPG, at a pressure slightly above atmospheric, into the intake manifold, where it enters the combustion chamber and is ignited with the diesel. LPG flow is regulated to ensure smooth operation, and will typically only deliver LPG under power.

Some companies claim a 10% to 20% increase in power and torque, and a reduction in overall fuel costs. Any actual savings are dependent on the relative cost of diesel versus LPG. In Australia, where diesel costs substantially more then LPG, savings of 10 to 20% are claimed.

Automotive Accessories : Spark Plug Voltage Stabilizer

* for Petrol/Gasoline vehicles

The spark [at the spark plug] is fundamental to cause ignition and thus combustion of the Air/Fuel mixture.

Spark at the spark plug is created by a high voltage that comes from the ignition coil.

The +12 Volt car battery is the main power source to many users of a vehicle; i.e.

* air conditioner
* head-lights
* wipers
* hi-fi and radio
* other electrical items, etc

As such, consistent supply cannot be guaranteed to the ignition coil via the +12 Volt Car Battery. When this happens, the spark may be too small to cause burning of the Air/Fuel mixture, or mis-firing, causing 100% unburn fuel to be released to the environment through the exhaust system.

This is also true when the vehicle is running at high rpm, and sparkings has to take place in shorter interval. So, when the car battery is not able to consistently supply the same power to the ignition coil, smaller or no sparking will occur.


Concept of Work

The Spark Plug Voltage Stabilizer is installed at the front of the ignition coil(s).

The Spark Plug Voltage Stabilizer concept of work is to take residual energy from the car and make it into good use. It relies less of the car battery in supplying the require power to the ignition coil. Revolutionary circuit design allows more Sparks.And this is achieved through a much higher Voltage delivery to the spark plugs.

* Impact of Optimized sparks
o Reducing unburn fuel will improve Fuel Consumption; because of less wastage [unburn fuel].
o The result of better burning improves car response, increasing power to the vehicle.


Types of Ignition Coils

The Spark Plug Voltage Stabilizer works on all different types of Ignition Coil Designs.

Earlier car design has the ignition coil as a separate unit. It is then connected to a 'distributor unit' which will sequence the high voltage generated to the respective spark plug.

Current design for single ignition coil system is called the 'Built-In Coil'. This houses both the Ignition Coil and Distributor as one unit.

* Single Coil - works with a separate Distributor unit
* Built-In Coil - Ignition Coil and Distributor unit in one
* Multi Coil; may be
o 2 Ignition coils
+ 1 Ignition coil to 2 spark plugs, or
+ 1 Ignition coil to 3 spark plugs [V6 engine]
o 3 coils
+ 1 Ignition coil to 1 spark plug, [3 cylinders engine eg. Perodua [Malaysia] or
+ 1 Ignition coil to 2 spark plugs [V6 engine]
o 4 coils
+ 1 Ignition coil to 1 spark plug [DIS - Direct Ignition Coil System, or Distributorles Ignition Coil System]
o More than 4 Coils, such as 6 coils (V6 engine), etc


Factors to better Fuel Consumption

There are many websites giving advice to improve fuel economy. Beside ensuring the vehicles at tip top conditions, the right foot is key! However, to attack the problem at the source; the Spark Plug Voltage Stabilizer has its merit.

Other products are available in the car accessories market to help in this area. Some of them, notably are :

*
o Voltage Stabilizer
o Magnet systems on the fuel line
o Fuel additives
o Cold Air Intake
o Special Air Filters
o Special Engine Oils
o Special Spark Plugs
o Highly Conductive Spark Plug Cables
o Your Right Foot, artificial or otherwise

*
o Latest product in the market : Patented composite material 'Titanium Ceramic' that influence the breaking up of clustered Air Molecules that allow easier combustion in the cylinder.

Key Engine Parts

key components inside an engine

Spark plug
The spark plug supplies the spark that ignites the air/fuel mixture so that combustion can occur. The spark must happen at just the right moment for things to work properly.

Valves
The intake and exhaust valves open at the proper time to let in air and fuel and to let out exhaust. Note that both valves are closed during compression and combustion so that the combustion chamber is sealed.

Piston
A piston is a cylindrical piece of metal that moves up and down inside the cylinder.

Piston rings
Piston rings provide a sliding seal between the outer edge of the piston and the inner edge of the cylinder. The rings serve two purposes:

* They prevent the fuel/air mixture and exhaust in the combustion chamber from leaking into the sump during compression and combustion.
* They keep oil in the sump from leaking into the combustion area, where it would be burned and lost.

Most cars that "burn oil" and have to have a quart added every 1,000 miles are burning it because the engine is old and the rings no longer seal things properly.

Connecting rod
The connecting rod connects the piston to the crankshaft. It can rotate at both ends so that its angle can change as the piston moves and the crankshaft rotates.

Crankshaft
The crankshaft turns the piston's up and down motion into circular motion just like a crank on a jack-in-the-box does.

Sump
The sump surrounds the crankshaft. It contains some amount of oil, which collects in the bottom of the sump (the oil pan).

Operation and working cycle for Hot bulb engine

The hot-bulb engine shares its basic layout with nearly all other internal combustion engines, in that it has a piston inside a cylinder connected to a flywheel via a connecting rod and crankshaft. The flow of gases through the engine is controlled by valves. The majority operate on the standard 4-stroke cycle of an Induction Stroke, a Compression Stroke, a Power Stroke and an Exhaust Stroke.

The main feature of the hot-bulb engine is the vaporiser or hot-bulb, a chamber usually cast into the engine block and attached to the main cylinder by a narrow opening. Prior to starting the engine from cold, this vaporiser is heated externally by a blow-lamp or slow-burning wick (on later models sometimes electric heating or pyrotechnics was used) for as much as half an hour. The engine is then turned over, usually by hand but sometimes by compressed air or an electric motor.

Air is drawn into the cylinder through the intake valve as the piston descends (The Induction Stroke). During the same stroke, fuel is injected into the hot-bulb by a mechanical jerk-pump through a nozzle. Through the action of the injector and the heat of the hot-bulb, the fuel instantly vapourises. The air in the cylinder then forced through the top of the cylinder as the piston rises (The Compression Stroke), through the opening into the hot-bulb, where it is compressed and therefore its temperature rises. The vaporised fuel mixes with the compressed air and ignites due to the heat of the compressed air and the heat applied to the hot-bulb prior to starting. The fuel ignites, driving the piston down (The Power Stroke). The piston's action is converted to a rotary motion by the crankshaft which drives the flywheel, to which equipment can be attached for work to be performed. The flywheel also conserves momentum to turn the engine over the three strokes when power is not being produced. The piston rises again and the exhaust gases are expelled through the exhaust valve (The Exhaust Stroke). The cycle then starts again.

Once the engine is running, the heat of compression and ignition maintains the hot-bulb at the necessary temperature and the blow-lamp or other heat source can be removed. From this point the engine requires no external heat and requires only a supply of air, fuel oil and lubricating oil to run. The fact that the engine could be left unattended for long periods whilst running made hot bulb engines popular choices for powering generators and pumps.

Hot bulb engine Differences from the Diesel Engine

The hot-bulb engine is often confused with the diesel engine, and it is true that the two engines are very similar. Aside from the obvious lack of a hot-bulb vaporiser in the diesel engine, the main differences are that:

* The hot-bulb engine uses both compression-ignition and the heat retained in the vaporiser to ignite the fuel.

* The diesel engine uses just compression-ignition to ignite the fuel, and it operates at pressures many times higher than the hot-bulb engine.

Due to the much greater and longer-term success of the diesel engine, today hot-bulb engines are sometimes called 'semi-diesels' or 'semi diesel' because they partly use compression-ignition in their cycle.

There is also a detail difference in the timing of the fuel injection process:

* In the hot-bulb engine, fuel is injected into the vapouriser during the Induction Stroke as air is drawn into the cylinder.

* In the diesel engine, fuel is injected into the cylinder in the final stages of the Compression Stroke.

However, Diesel's original engine design used compressed air to blast the fuel into the cylinder. This complex and heavy system limited the speed the engine could run at and the minimum size a diesel engine could be built to. This was needed to inject fuel under sufficient pressure for it to enter the highly compressed air in the cylinder. In hot-bulb engines fuel is injected before compression takes place, allowing a lighter, more accurate injection system to be used. Only when Akroyd-Stuart's mechanical pump-and-injector system that he developed for his hot-bulb engine was adapted by Robert Bosch for use in diesel engines (by making the system run at a much higher pressure) were high-speed diesel engines practical.

Swashplate engine

The swashplate engine is a type of reciprocating engine that replaces the common crankshaft with a circular plate (the swashplate). Pistons press down on a circular plate in a circular sequence, forcing it to nutate around its center. This motion can be simulated by placing a CD on a ball bearing at its centre and pressing down at progressive places around its circumference. The plate, also known as a wobble plate, is typically geared to produce rotary motion. An alternate design replaces the plate with a sine-shaped cam, and is thus known as a cam engine.

The key advantage of the design is that the cylinders are arranged in parallel around the edge of the plate, and possibly on either side of it as well, and are aligned with the output shaft rather than at 90 degrees as in crankshaft engines. This results in a very compact, cylindrical engine. For this reason the design is also known as a barrel engine.

The arrangement also allows the compression ratio of the engine to be changed whilst running by adjusting the distance of the plate from the cylinders.


Applications

Swashplate engines are particularly interesting in the aircraft engine role, where their compact size is valuable. However, it appears no swashplate engine has ever been widely used in this role, although there have been numerous attempts to introduce one. This may not be any fault of the design, but the designers themselves. It appears that anyone working on these "oddball" engine designs seems to try to include every advanced feature known at the time, instead of using known technology where possible. The result are designs that never seem to mature.

A more successful application is in torpedoes, where the cylindrical shape is desirable. For example, the modern Mark 48 torpedo is powered by a swashplate engine.

Other applications include pneumatic and hydraulic motors and hydrostatic transmissions. Also some Stirling engines use swashplate arrangement.


History

The first known swashplate engine design was introduced by Statax-Motor of Zurich, Switzerland in 1913. Only a single prototype was produced, which is currently held in the Kensington Museum in London. In 1914 the company moved to London to become the Statax Engine Company and planned on introducting a series of rotary engines; a 3 cylinder of 10 hp, a 5 cyl of 40 hp, a 7 cyl of 80 hp, and a 10 cyl of 100 hp. It appears only the 40 hp design was ever produced, and installed in a Caudron G.II for the British 1914 Aerial Derby but was withdrawn before the flight. Hansen introduced an all-aluminum version of this design in 1922, but it is not clear if it was produced in any quantity. Much improved versions were introduced by Statax's German division in 1929, producing 42 hp in a new sleeve valve version known as the 29B. Greenwood and Raymond of San Francisco acquired the patent rights for the US, Canada, and Japan, and planned a 5 cylinder of 100 hp and a 9 cylinder of 350 hp.

Experimental barrel engines for aircraft use were built and tested by Mr J.O. Almen of Seattle, WA in the early 1920s, and by the mid-1920s the water-cooled Almen A-4 (18 cylinders, two groups of nine each horizontally opposed) had passed its United States Air Corps acceptance tests. It however never entered production, reportedly due to limited funds and the Air Corps' growing emphasis on air-cooled radial engines. The A-4 had much smaller frontal area than water-cooled engines of comparable power output, and thereby offered better streamlining possibilities. It was rated at 425 horsepower (317 kW), and weighed only 749 pounds (340 kg), thus giving a power/weight ratio of better than 1:2, a considerable design achievement at the time.

Indian motorcycle also introduced a swashplate engine, the Alfaro, in 1938. The Alfaro is a perfect example of the "put in everything" design, as it included a sleeve valve system based on a rotating cylinder head, a design that never entered production on any engine.

Stephen DuPont in 2006 wrote a small book, A 1911 Spanish Pilot and MIT Aeroengineer and his 1938 Aeroengine Upgraded for Today, ISBN 0-9777134-0-7, which details the development of a barrel engine for aircraft and contains a brief biography of its inventor, Heraclio Alfaro. DuPont was the son of the founder of the Indian motorcycle company; Alfaro was one of his professors at MIT. DuPont later worked further on developing the barrel engine, particlarly for a helicopter, the Doman.

Some small barrel engines were produced by the H.L.F. Trebert Engine Works of Rochester, New York for marine usage.

Perhaps the most refined of the designs was the British Wooler motorcycle engine of 1937. This design used two pistons per cylinder, moving in opposite directions (see the Junkers Jumo 205 for details). The connecting rods attached to a tilting plate through ball joints, and the plate in turn drove a swashplate for power.

More recently, Axial Vector Engine Company has been attempting to re-introduce the concept, although with limited success to date. Their engine, like many of the others on this list, also suffers from the "put in everything" problem, including piezoelectric valves and ignition, ceramic cylinder liners with no piston rings, and a variety of other advanced features.

Axial piston pump

An axial piston pump is a positive displacement pump that has a number of pistons in a circular array within a cylinder block. It can be used as a stand-alone pump or as a hydraulic motor.


Description

An axial piston pump has a number of pistons (usually an odd number) arranged in a circular array within a housing which is commonly referred to as a cylinder block, rotor or barrel. This cylinder block is driven to rotate about its axis of symmetry by an integral shaft that is, more or less, aligned with the pumping pistons (usually parallel but not necessarily).

* Mating surfaces. One end of the cylinder block is flat and wears against a mating surface on a stationary valve plate. The inlet and outlet fluid of the pump pass through different parts of the sliding interface between the cylinder block and valve plate. The valve plate has two semi-circular ports that allow inlet of the operating fluid and exhaust of the outlet fluid respectively.

* Protruding pistons. The pumping pistons protrude from the opposite end of the cylinder block. There are numerous configurations used for the exposed ends of the pistons but in all cases they bear against a cam. In variable displacement units, the cam is movable and commonly referred to as a swash plate, yoke or hanger. For conceptual purposes, the cam can be represented by a plane, the orientation of which, in combination with shaft rotation, provides the cam action that leads to piston reciprocation and thus pumping. The angle between a vector normal to the cam plane and the cylinder block axis of rotation, called the cam angle, is one variable that determines the displacement of the pump or the amount of fluid pumped per shaft revolution. Variable displacement units have the ability to vary the cam angle during operation whereas fixed displacement units do not.

* Reciprocating pistons. As the cylinder block rotates, the exposed ends of the pistons are constrained to follow the surface of the cam plane. Since the cam plane is at an angle to the axis of rotation, the pistons must reciprocate axially as they precess about the cylinder block axis. The axial motion of the pistons is sinusoidal. During the rising portion of the piston's reciprocation cycle, the piston moves toward the valve plate. Also, during this time, the fluid trapped between the buried end of the piston and the valve plate is vented to the pump's discharge port through one of the valve plate's semi-circular ports - the discharge port. As the piston moves toward the valve plate, fluid is pushed or displaced through the discharge port of the valve plate.

* Effect of precession. When the piston is at the top of the reciprocation cycle (commonly referred to as top-dead-center or just TDC), the connection between the trapped fluid chamber and the pump's discharge port is closed. Shortly thereafter, that same chamber becomes open to the pump's inlet port. As the piston continues to precess about the cylinder block axis, it moves away from the valve plate thereby increasing the volume of the trapped chamber. As this occurs, fluid enters the chamber from the pump's inlet to fill the void. This process continues until the piston reaches the bottom of the reciprocation cycle - commonly referred to as bottom-dead-center or BDC. At BDC, the connection between the pumping chamber and inlet port is closed. Shortly thereafter, the chamber becomes open to the discharge port again and the pumping cycle starts over.

* Variable displacement. In a variable displacement unit, if the vector normal to the cam plane (swash plate) is set parallel to the axis of rotation, there is no movement of the pistons in their cylinders. Thus there is no output. Movement of the swash plate controls pump output from zero to maximum.

* Pressure. In a typical pressure-compensated pump, the swash plate angle is adjusted through the action of a valve which uses pressure feedback so that the instantaneous pump output flow is exactly enough to maintain a designated pressure. If the load flow increases, pressure will momentarily decrease but the pressure-compensation valve will sense the decrease and then increase the swash plate angle to increase pump output flow so that the desired pressure is restored. In reality most systems use pressure as a control for this type of pump. The operating pressure reaches, say, 200 bar (2 MPa or 3000 psi) and the swash plate is driven towards zero angle (piston stroke nearly zero) and with the inherent leaks in the system allows the pump to stabilise at the delivery volume that maintains the set pressure. As demand increases the swash plate is moved to a greater angle, piston stroke increases and the volume of fluid increases, if the demand slackens the pressure will rise and the pumped volume diminishes as the pressure rises. At maximum system pressure the output is almost zero again. If the fluid demand increases, beyond the capacity of the pump's delivery, the system pressure will drop near to zero. The swash plate angle will remain at the maximum allowed and the pistons will operate at full stroke. This continues until system flow-demand eases and the pump's capacity is greater than demand. As the pressure rises the swash-plate angle modulates to try to not exceed the maximum pressure while meeting the flow demand.


Design difficulties

Designers have a number of problems to overcome in designing axial piston pumps. One is managing to be able to manufacture a pump with the fine tolerances necessary for efficient operation. The mating faces between the rotary piston-cylinder assembly and the stationary pump body have to be almost a perfect seal while the rotary part turns at, maybe, 3000 rpm. The pistons are usually less than half an inch (13 mm) in diameter with similar stroke lengths. Keeping the wall to piston seal tight means that very small clearances are involved and that materials have to be closely matched for similar coefficient of expansion.

The pistons have to be drawn outwards in their cylinder by some means. On small pumps this can be done by means of a spring inside the cylinder that forces the piston up the cylinder. Inlet fluid pressure can also be arranged so that the fluid pushes the pistons up the cylinder. Often a vane pump is located on the same drive shaft to provide this pressure and it also allows the pump assembly to draw fluid against some suction head from the reservoir, which is not an attribute of the unaided axial piston pump.

Another method of drawing pistons up the cylinder is to attach the cylinder heads to the surface of the swash plate. In that way the piston stroke is totally mechanical. However, the designer's problem of lubricating the swash plate face (a sliding contact) is made even more difficult.

Internal lubrication of the pump is achieved by use of the operating fluid—normally called hydraulic fluid. Most hydraulic systems have a maximum operating temperature, limited by the fluid, of about 120 °C (250 °F) so that using that fluid as a lubricant brings its own problems. In this type of pump the leakage from the face between the cylinder housing and the body block is used to cool and lubricate the exterior of the rotating parts. The leakage is then carried off to the reservoir or to the inlet side of the pump again. Hydraulic fluid that has been used is always cooled and passed through micrometre-sized filters before recirculating through the pump.


Uses

Despite the problems indicated above this type of pump can contain most of the necessary circuit controls integrally (the swash-plate angle control) to regulate flow and pressure, be very reliable and allow the rest of the hydraulic system to be very simple and inexpensive.

Axial reciprocating motors are also used to power many machines. They operate on the same principle as described above, except that the circulating fluid is provided under considerable pressure and the piston housing is made to rotate and provide shaft power to another machine. A common use of an axial reciprocating motor is to power small earthmoving plant such as skid loader machines. Another use is to drive the screws of torpedoes.

Integrated Motor Assist

Integrated Motor Assist (commonly abbreviated as IMA) is Honda's hybrid car technology, introduced in 1999 on the Insight. It uses an electric motor mounted between the engine and transmission to act as a starter motor, engine balancer, and assist traction motor. In its first generation, IMA could not power the car on electricity alone, and could only use the motor to assist or start the engine. The 2006 Civic Hybrid, however, can activate the electric motor while the vehicle is coasting without turning the ICE on, though in contrast to Toyota's Hybrid Synergy Drive (HSD) or General Motors and DaimlerChrysler's Global Hybrid Cooperation, the IMA has a less powerful motor/generator which allows the car to slow or stop its rate of deceleration to a lesser extent; it cannot operate without turning over the ICE which is directly coupled to its electric motor.

The theory behind IMA is to use regenerative braking to recapture some of the energy lost through deceleration, and reuse that energy later on to help accelerate the vehicle. This has two effects: it increases the rate of acceleration, and it reduces the work required of the gasoline engine. The acceleration boost is important as it allows the engine to be scaled down to a smaller but more fuel-efficient variant without rendering the vehicle overly slow or weak. This smaller engine is the primary reason cars equipped with IMA get better highway mileage than their more conventional counterparts.

Additionally, vehicles equipped with IMA can shut off their engine when the vehicle stops and use the electric motor to rapidly spin it back up when the driver releases the brake pedal. They also have a conventional starter as a backup, making it the only production hybrid system which can operate with its high voltage electric system disabled, using only its ICE like a traditional vehicle. However, since the IMA also acts as the vehicle's alternator, eventually the 12 V accessory battery would require an external charge.

Honda produced a high-performance IMA motor for the Dualnote concept car. The engine was a 3.5 liter DOHC i-VTEC V6 motor featuring "new-generation" IMA. It was estimated to produce 400 horsepower while still being capable of fuel efficiency of approximately 18 km/liter (42 mpg).

DaimlerChrysler BlueTec

BlueTec is DaimlerChrysler's name for its two nitrogen oxide (NOx) reducing systems, for use in their Diesel automobile engines. One is a urea based reductant called AdBlue, the other is called DeNOx and uses an oxidising catalytic converter and particulate filter combined with other NOx reducing systems. Both systems are designed to reduce pollutant emissions.

The BlueTec was on the Ward's 10 Best Engines list for 2007.



Uses

Mercedes-Benz introduced the systems in the E-Class (using the 'DeNOx' system) and GL-Class (using 'AdBlue') at the 2006 North American International Auto Show as the E320 and GL320 Bluetec vehicles. This system makes these vehicles 45-state and 50-state legal, respectively in the United States, and is expected to meet all emissions regulations through 2009.

A Jeep Grand Cherokee with the same Bluetec engine is also expected, and Mercedes announced tentative plans for a BLUETEC/electric hybrid S-Class.

Volkswagen has introduced the Jetta Clean TDI, the Tiguan concept and the VW Touareg BlueTDI as part of the BlueTec program. All are expected to be introduced in the American market in 2008. The Jetta and the Tiguan use NOx Adsorbers, while the Toureg uses a Selective Catalytic Reduction catalystic converter.

DaimlerChrysler has entered an into agreement with Volkswagen and Audi to share BlueTec technology with them in order to increase the Diesel passenger-vehicle market in the US.


Rationale

The BlueTec system was created because the processes that give diesel engines efficient fuel economy also creates extra emissions of certain pollutants. High compression ratios and lean air-fuel mixtures make high combustion temperatures, which results in more nitrogen oxides and Diesel Particulate Matter (also known as smoke) being released into the atmosphere. While the particulate matter can be controlled with higher injection pressures and particulate filters, the big challenge is limiting NOx (Tier 2 regulations in the US are 0.05 gram per mile of NOx, which is ⅛ of the 0.40 limit in the European Union).


Process

The Bluetec system will use two catalytic converters specifically targeting NOx. The first converter traps the NOx, and later releases it to the second converter which then converts it to nitrogen (N2) and water (H2O). This will make a diesel car legal in 45 states. But to make it pass the more stringent regulations of California, Maine, Massachusetts, New York and Vermont, AdBlue (NH4) will have to be introduced into the system, making the conversion more complete.



The whole exhaust system would work like so:

1. A Diesel oxidation catalyst reduces carbon monoxide (CO) and hydrocarbons (HC) released from the exhaust.

2. A DeNOx catalytic converter begins a preliminary removal of oxides of nitrogen.

3. A particulate filter will trap and store smoke particles, burning them off when the filter gets full.

4. If the above are not sufficient to meet the exhaust specifications, a Selective Catalytic Reduction (SCR) catalytic converter will take the remaining nitrogen oxides and covert them to nitrogen and water. AdBlue will be injected into it to help the conversion.

Antiknock agent

An antiknock agent is a gasoline additive used to reduce engine knocking and increase the fuel's octane rating.

The mixture known as gasoline, when used in high compression internal combustion engines, has a tendency to ignite early (pre-ignition or detonation) causing a damaging "engine knocking" (also called "pinging" or "pinking") noise. Early research into this effect was led by A.H. Gibson and Harry Ricardo in England and Thomas Midgley and Thomas Boyd in the United States. The discovery that lead additives modified this behavior led to the widespread adoption of the practice in the 1920s and therefore more powerful higher compression engines. The most popular additive was tetra-ethyl lead. However, with the discovery of the environmental and health damage caused by the lead, and the incompatibility of lead with catalytic converters found on virtually all US automobiles since 1975, this practice began to wane in the 1980s. Most countries are phasing out leaded fuel; different additives have replaced the lead compounds. The most popular additives include aromatic hydrocarbons, ethers and alcohol (usually ethanol or methanol).

The typical antiknock agents in use are:

* Tetra-ethyl lead (phased out)
* Methylcyclopentadienyl manganese tricarbonyl (MMT)
* Ferrocene
* Iron pentacarbonyl
* Toluene
* Isooctane


Tetra-ethyl lead

In the U.S., where lead was blended with gasoline (primarily to boost octane levels) since the early 1920s, standards to phase out leaded gasoline were first implemented in 1973. In 1995, leaded fuel accounted for only 0.6 % of total gasoline sales and less than 2,000 tons of lead per year. From January 1, 1996, the Clean Air Act banned the sale of leaded fuel for use in on-road vehicles. Possession and use of leaded gasoline in a regular on-road vehicle now carries a maximum $10,000 fine in the United States. However, fuel containing lead may continue to be sold for off-road uses, including aircraft, racing cars, farm equipment, and marine engines until 2008. The ban on leaded gasoline led to thousands of tons of lead not being released in the air by automobiles. Similar bans in other countries have resulted in lowering levels of lead in people's bloodstreams.

A side effect of the lead additives was protection of the valve seats from erosion. Many classic cars' engines have needed modification to use lead-free fuels since leaded fuels became unavailable. However, "Lead substitute" products are also produced and can sometimes be found at auto parts stores.

Gasoline, as delivered at the pump, also contains additives to reduce internal engine carbon buildups, improve combustion, and to allow easier starting in cold climates.

In some parts of South America, Asia and the Middle East, leaded gasoline is still in use. Leaded gasoline was phased out in sub-Saharan Africa with effect from 1 January, 2006. A growing number of countries have drawn up plans to ban leaded gasoline in the near future.

To avoid deposits of lead inside the engine, lead scavengers are added to the gasoline together with tetra-ethyl lead. The most common ones are:

* Tricresylphosphate
* 1,2-Dibromoethane
* 1,2-Dichloroethane


MMT

Methylcyclopentadienyl manganese tricarbonyl (MMT) has been used for many years in Canada and recently in Australia to boost octane. It also helps old cars designed for leaded fuel run on unleaded fuel without need for additives to prevent valve problems.

US Federal sources state that MMT is suspected to be a powerful neurotoxin and respiratory toxin, and a large Canadian study concluded that MMT impairs the effectiveness of automobile emission controls and increases pollution from motor vehicles.

Uniflow steam engine

The uniflow type of steam engine uses steam that flows in one direction only in each half of the cylinder. Thermal efficiency is increased in the compound and multiple expansion types of steam engine by separating expansion into steps in separate cylinders; in the uniflow design, thermal efficiency is achieved by having a temperature gradient along the cylinder. Steam always enters at the hot ends of the cylinder and exhausts through ports at the cooler centre. By this means the relative heating and cooling of the cylinder walls is reduced.


Design details

Steam entry is usually controlled by poppet valves (which act similarly to those used in internal combustion engines) that are operated by a camshaft. The inlet valves open to admit steam when minimum expansion volume has been reached at the start of the stroke. For a period of the crank cycle steam is admitted and the poppet inlet is then closed, allowing continued expansion of the steam during the stroke, driving the piston. Near the end of the stroke the piston will expose a ring of exhaust ports mounted radially around the centre of the cylinder. These ports are connected by a manifold and piping to the condenser, lowering the pressure in the chamber to below that of the atmosphere causing rapid exhausting. Continued rotation of the crank moves the piston. From the animation the features of a uniflow engine can be seen, with a large piston almost half the length of the cylinder, poppet inlet valves at either end, a camshaft (whose motion is derived from that of the driveshaft) and a central ring of exhaust ports.


Advantages

Uniflow engines potentially allow greater expansion in a single cylinder without the relatively cool exhaust steam flowing across the hot end of the working cylinder and steam ports of a conventional "counterflow" steam engine during the exhaust stroke. This condition allows high thermal efficiency. The exhaust ports are only open for a small fraction of the piston stroke, therefore not all of the expanded steam is able to exhaust. This remaining steam is compressed by the returning piston and is thermodynamically desirable as it preheated the hot end of the cylinder before the admission of steam. However, the risk of excessive compression often resulted in small auxiliary exhaust ports being included at the cylinder heads. Such a design is called a semi-uniflow engine.

Engines of this type usually have multiple cylinders in an inline arrangement and may be single or double acting. A particular advantage of this type is that the valves may be operated by the effect of multiple camshafts, and by changing the relative phase of these camshafts, the amount of steam admitted may be increased for high torque at low speed and may be decreased at cruising speed for economy of operation, and by changing the absolute phase the engine's direction of rotation may be changed. The uniflow design also maintains a constant temperature gradient through the cylinder, avoiding passing hot and cold steam through the same end of the cylinder.



Disadvantages

In practice the uniflow engine has a number of operational shortcomings. The large expansion ratio requires a large cylinder volume. To gain the maximum potential work from this a high reciprocation rate was required, typically 80% faster than a double-acting engine. This caused the opening times of the inlet valves to be very short, putting great strain on a delicate mechanical part. In order to withstand the huge mechanical forces encountered, engines had to be heavily built and a large flywheel was required to smooth out the variations in torque as the steam pressure rapidly rose and fell in the cylinder. Additionally, as there was a thermal gradient across the cylinder, the metal of the wall expanded to different extents. This required precise boring of the cylinder barrel to be wider in the cool centre than at the hot ends. If the cylinder was not heated correctly, or if water entered, the delicate balance could be upset causing seizure mid-stroke or, potentially, destruction.



History

The uniflow engine was first used in Britain in 1827 by Jacob Perkins and was patented in 1885 by Leaonard Jennett Todd. It was popularised by German engineer Johann Stumpf in 1909, with the first commercial stationary engine produced a year previously in 1908.

The uniflow principle was mainly used for in industrial power generation, but was also tried in a few railway locomotives in England, such as The NER Uniflow Locomotive No 825 of 1913, The NER Uniflow Locomotive No 2212 of 1919, and The Midland Railway Paget locomotive. Experiments were also made in the USA and Russia. In no case were the results encouraging enough for further development to be undertaken.

The final commercial evolution of the Uniflow engine occurred in the USA during the late 1930s and 1940s by the Skinner Engine Company with the development of the Compound Unaflow Marine Steam Engine. This engine operated in a steeple compound configuration and provided efficiencies approaching contemporary diesels. Many bulk carriers and ferries on the Great Lakes were so equipped, several of which are still operating.

In small sizes (less than about 1000 horsepower ), reciprocating steam engines are much more efficient than steam turbines. The Whitecliffs solar steam power plant uses a three cylinder uniflow engine to generate about 25 kW electric output.

What is a Timing Curve?

The timing curve is the mechanical timing values plotted over an RPM curve. What this means is that at a given RPM based upon the weights and springs used in the distributor you will have a specified amount of timing advance. Remember, as your engine RPM increases, so does the inertia against the distributor weights within the distributor. The springs holding the weights is the opposite resistance force that controls the speed, or rate, that the weights move "out" causing the distributor advance plate to move which advances the timing. So, what happens is that at each RPM change there is a variance in the amount of timing advance up to a point in which the weights usually hit a "stop" that does not allow them to move out (advance the distributor) beyond that point.

Changing the springs to a lighter one (or both) will make the advance occur faster, and of course running a heavier (stronger) spring will slow the advance rate. You can also in most cases modify the weights (or stops) as to what the advance limit will be. Mixing springs to control the desired advance rate is how you modify your timing curve.

What is Initial Timing and Total Timing?

Initial timing is that setting you make while your engine is idling with a timing light. This is typically between 4° ATDC (After Top Dead Center) to 16° BTDC (Before Top Dead Center). For performance applications "in most cases" you want as much initial timing as the starter can handle (the more timing the more cylinder pressure that the starter must overcome to crank the engine). Too much initial timing, besides the starter load, can also run the HC (Hydrocarbon) emission levels beyond legal or breathable levels .

Total timing is the calculation of the combined initial and mechanical advance timing settings (max). This "can" also include your vacuum advance though, I like to describe it as "total timing plus vacuum advance". Since vacuum advance is a nearly inconsistent value I like to use it after I have set up the correct mechanical values in the distributor. At times I must use the vacuum advance to generate the timing values I require, but I try to only use it as an "economy" tool to give a street driven vehicle more efficiency and throttle response by this addition.

Ignition timing

Ignition timing in an internal combustion engine is the process of setting the time that a spark will occur in the combustion chamber (during the power stroke) relative to piston position and crankshaft angular velocity. Setting the correct ignition timing is crucial in the performance of an engine. The ignition timing affects many variables including engine longevity, fuel economy, and engine power. Modern engines that are controlled by an engine control unit use a computer to control the timing throughout the engine's RPM range. Older engines that use mechanical spark distributors rely on inertia (by using rotating weights and springs) and manifold vacuum in order to set the ignition timing throughout the engine's RPM range. There are many factors that influence ignition timing. These include which type of ignition system is used, engine speed and load, which components are used in the ignition system, and the settings of the ignition system components. Usually, any major engine changes or upgrades will require a change to the ignition timing settings of the engine.



History

The ignition systems of older, non-computer controlled engines consists of a mechanical spark distributor which distributes spark to cylinders based on an initial timing advance, mechanical timing advance, and vacuum timing advance. In 1972, Chrysler introduced the electronic ignition system that controlled ignition timing and fuel delivery, replacing the mechanical spark distributor and therefore mechanical and vacuum timing advance. This system led to the advanced automobile electronic systems of today’s automobiles. Ignition systems will continue to improve as ignition components become more technologically advanced.


Setting the Ignition Timing

“Timing advance” refers to the number of degrees before top dead center (BTDC) that the spark will ignite the air-fuel mixture in the combustion chamber during the power stroke. “Timing retard” refers to the number of degrees after top dead center (ATDC) that the spark will ignite the air-fuel mixture during the power stroke.

Timing advance is required because it takes time to burn the air-fuel mixture. Igniting the mixture before the piston reaches top dead center (TDC) will allow the mixture to become fully burnt soon after the piston reaches TDC. If the air-fuel mixture is ignited at the correct time, maximum pressure in the cylinder will occur sometime after the piston reaches TDC allowing the ignited mixture to push the piston down the cylinder. Ideally, the time at which the mixture should be fully burnt is about 20 degrees ATDC. This will utilize the engines power producing potential. If the ignition spark occurs at a position that is too advanced relative to piston position, the rapidly expanding air-fuel mixture can actually push against the piston causing detonation and lost power. If the spark occurs too retarded relative to the piston position, maximum cylinder pressure will occur after the piston is already traveling too far down the cylinder. This results in lost power, high emissions, and unburned fuel.

The ignition timing will need to become increasingly advanced (relative to TDC) as the engine speed increases so that the air-fuel mixture has the correct amount of time to fully burn. Another reason for advancing the timing is because as the engine speed increases, fuel consumption increases. Since more fuel is present in the cylinder, the time required to fully burn the air-fuel mixture will be longer. Poor volumetric efficiency at lower engine speeds also requires increased advancement of ignition timing. The correct timing advance for a given engine speed will allow for maximum cylinder pressure to be achieved at the correct crankshaft angular position. When setting the timing for an automobile engine, the factory timing setting can usually be found on a sticker in the engine bay.


Dyno Tuning

Setting the ignition timing while monitoring engine power output with a dynamometer is an excellent way to correctly set the ignition timing. After advancing or retarding the timing, a corresponding change in power output will usually occur. Using a knock sensor to find the correct timing is one method used to tune an engine. In this method, the timing is advanced until knock occurs. The timing is then retarded one or two degrees and set there. After achieving the desired power characteristics for a given engine load/rpm, the spark plugs should be inspected for signs of engine detonation. If there are signs of detonation, the ignition timing should be retarded until there are no signs of detonation.


Mechanical Ignition Systems

Mechanical ignition systems use a mechanical spark distributor to distribute a high voltage current to the correct spark plug at the correct time. In order to set an initial timing advance or timing retard for an engine, the engine is allowed to idle and the distributor is adjusted to achieve the best ignition timing for the engine at idle speed. This process is called 'setting the base advance'. There are two methods of increasing timing advance past the base advance. The advances achieved by these methods are added to the base advance number in order to achieve a total timing advance number.


Mechanical Timing Advance

An increasing mechanical advancement of the timing takes place with increasing engine speed. This is possible by using the law of inertia. Weights and springs inside the distributor rotate and affect the timing advance according to engine speed. This type of timing advance is also referred to as centrifugal timing advance. The amount of mechanical advance is dependant solely on the speed at which the distributor is rotating. In a 2-stroke engine, this is the same as engine RPM. In a 4-stroke engine, this is half the engine RPM. The relationship between advance in degrees and distributor RPM can be drawn as a simple 2-dimensional graph.

Lighter weights or heavier springs can be used to reduce the timing advance at lower engine rpm's. Heavier weights or lighter springs can be used to advance the timing at lower engine rpm's.

Most vehicle manufacturers specify that the vacuum line for the vacuum advance (if equipped) should be disconnected and plugged when setting the initial advance. Be careful when turning the distributor while the engine is running because deteriorated spark plug wires can deliver a dangerous shock.


Vacuum Timing Advance

The second method used to advance the ignition timing is called vacuum timing advance. This method is sometimes (depending on the engine manufacturer) used in addition to mechanical timing advance. Usually, this method is used to increase fuel economy. Vacuum advance works by using a vacuum source to advance the timing at mid engine load conditions. Vacuum advance is diminished at wide open throttle (WOT), causing the timing advance to return to the base advance in addition to the mechanical advance.

The most common vacuum source for vacuum advance is a small port located in the wall of the throttle body or carburetor adjacent to but slightly upstream of the edge of the throttle plate. In carburetors having primary and secondary throttle plates, the port is located in the primary. The effect of having a hole here is that there is little or no vacuum at idle or at wide open throttle, with the vacuum signal peaking at part throttle opening.

On some vehicles, a temperature sensing switch will apply manifold vacuum to the vacuum advance system when the engine is overheating. The purpose of this is to increase engine speed to turn the engine fan faster to try to overcome the overheating.

On some vehicles, some form of switches may be used to prevent vacuum advance under certain conditions such as when the engine is cold or depending on what gear the vehicle is in. This is usually because these are necessary to comply with emission standards.


Electronic Ignition Systems

Newer engines typically use electronic ignition systems (ignition controlled by a computer). The computer has a timing map which is a chart with engine speed on one axis and engine load on another axis. Timing advance numbers are inserted in this chart. The computer will send a signal to the ignition coil at the indicated time in the timing map in order to spark the spark plug. Most computers from original equipment manufacturers (OEM) are not able to be modified so changing the timing advance is not possible. Aftermarket engine control units allow the user to make changes to the timing map. This allows the timing to be advanced or retarded based on various engine applications.

Lean burn

Lean burn is an internal combustion of lean air-fuel mixtures. It happens at very high air-fuel ratios (up to 65:1), so the mixture has considerably less amount of fuel in comparison to stoichiometric combustion ratio (14.6:1 for petrol).

The engines designed for lean burning can employ higher compression ratios and thus provide better performance, efficient fuel use and low exhaust emissions than those found in conventional petrol engines. Ultra lean mixtures with very high air-fuel ratios can only be achieved by Direct Injection engines.

The main drawback of lean burning is the large amount of NOx being generated, so a complex catalytic converter system is required. Lean burn engines do not work well with modern 3-way catalytic converters, which require a balance of pollutants at the exhaust port in order to carry out both oxidation and reduction reactions, so most modern engines run at or near the stoichiometric point.


Chrysler Lean Burn computer

From the late 1970s to mid 1980s, Chrysler equipped many of its North American production cars with a spark control computer which it called the Lean Burn Computer on the large sticker on the unit.

Mounted on the air filter housing of most rear-wheel drive cars Chrysler produced during this time, it was responsible for adjusting spark timing based on manifold vacuum, engine speed, engine temperature and incoming air temperature; by doing this, Chrysler eliminated the traditional vacuum and centrifugal timing advance mechanisms used on distributors in order to provide more accurate spark timing. It also provided drive for the ignition coil directly, eliminating the separate ignition module.

Based on an early computer system, most Lean Burn computers were an open-loop emissions control system with no provided diagnostic port or "Check Engine" warning light, were difficult to troubleshoot, and were greatly responsible for the poor reliability reputation which dogged Chrysler at the time.

Many Lean Burn computers were replaced with the more reliable electronic ignition module and centrifugal/vacuum advance distributors used on earlier Chrysler vehicles, almost universally to improvements in fuel economy and driveability.


Heavy-duty gas engines

Lean burn concepts are often used for the design of heavy-duty natural gas, biogas, and liquefied petroleum gas (LPG) fuelled engines. These engines can either be full-time lean burn, where the engine runs with a weak air-fuel mixture regardless of load and engine speed, or part-time lean burn (also known as "lean mix" or "mixed lean"), where the engine runs lean only during low load and at high engine speeds, reverting to a stoichiometric air-fuel mixture in other cases.

Heavy-duty lean burn gas engines admit as much as 75% more air than theoretically needed for complete combustion into the combustion chambers. The extremely weak air-fuel mixtures lead to lower combustion temperatures and increased forced induction possibilities (that would otherwise be limited by high exhaust gas temperatures), leading to higher theoretical efficiencies when compared to engines running on a stoichiometric air-fuel mixture.


Honda lean burn systems

One of the newest lean-burn technologies available in automobiles currently in production uses very precise control of fuel injection, a strong air-fuel swirl created in the combustion chamber, a new linear air-fuel sensor (LAF type O2 sensor) and a lean-burn NOx catalyst to further reduce the resulting NOx emissions that increase under "lean-burn" conditions and meet NOx emissions requirements.

This stratified-charge approach to lean-burn combustion means that the air-fuel ratio isn't equal throughout the cylinder. Instead, precise control over fuel injection and intake flow dynamics allows a greater concentration of fuel closer to the spark plug tip (richer), which is required for successful ignition and flame spread for complete combustion. The remainder of the cylinders' intake charge is progressively leaner with an overall average air:fuel ratio falling into the lean-burn category of up to 22:1.

The older Honda engines that used lean burn (not all did) accomplished this by having a parallel fuel and intake system that fed a pre-chamber the "ideal" ratio for initial combustion. This burning mixture was then opened to the main chamber where a much larger and leaner mix then ignited to provide sufficient power. During the time this design was in production this system (CVCC, Compound Vortex Controlled Combustion) primarily allowed lower emissions without the need for a catalytic converter. These were carburated engines and the relative "imprecise" nature of such limited the MPG abilities of the concept that now under MPI (Multi-Port fuel Injection) allows for higher MPG too.

The newer Honda stratified charge (lean burn engines) will operate on air-fuel ratios as high as 22:1. The amount of fuel drawn into the engine is much lower than a typical gasoline engine which operates at 14.7:1. That being the chemical stoichiometric ideal for complete combustion when averaging gasoline to be the petrochemical industries' accepted standard of C6H8.

This lean-burn ability by the necessity of the limits of physics, and the chemistry of combustion as it applies to a current gasoline engine must be limited to light load and lower RPM conditions. A "top" speed cut-off point is required since leaner gasoline fuel mixtures burn slower and for power to be produced combustion must be "complete" by the time the exhaust valve opens.


Applications

* 1993–95 Civic VX
* 1998–2000 Civic Hx
* 2001 Civic Hx
* 2002–06 Civic Hybrid
* 2000–06 Insight


Diesel engines

All diesel engines are lean burning. This is essential to the way they ignite the fuel.

Hit and miss engine

A type of four-stroke internal combustion engine that was commonly used in the early part of the 1900s. They serve no commercially significant function today and are mainly owned by hobbyists.

A typical hit and miss engine had a power of 2 to 10 HP and ran under full load at speeds of 400 to 1,000 RPM. They were used to power pumps for cultivation, saws, generators and other small stationary applications. They were used in applications where cost was a consideration and their simplicity of design reflected that requirement.

The term "hit and miss" comes from the sound that the engine makes when running at idle. The sound is most like an engine that is barely running: missing on several strokes and then hitting on one. Just hitting enough to keep the engine turning.

These were simple engines but they incorporated some very clever governor designs. It may be the originality in the design of the governor that is so fascinating for the hobbyist/collector. There is great variation in governor design from one manufacturer to another so there is no general design that will describe all engines.

Things that are common to most engines: there is no intake cam, the exhaust valve is held open to prevent the engine from building up compression or firing until the speed decreases, when the speed does decrease, the exhaust valve closes. A governor controls the exhaust valve and the magneto spark.

In operation: the engine fires and this increases its speed. The increased speed causes the governor to open the exhaust valve and to cut off the magneto spark. The engine then turns freely for several revolutions but slows to a point where the governor closes the exhaust valve. On the next downstroke of the piston, the closed combustion chamber draws a vacuum, the vacuum pulls the intake valve open and draws fuel and air into the combustion chamber. The piston then compresses the mixture, the spark ignites it and the engine is given one power stroke which increases its speed.

The number of power strokes to non-power strokes is a function of the load on the engine. When the engine is unloaded the ratio is several non-power strokes for each power stroke and the engine has its characteristic sound.

4-stroke power valve system

A 4-stroke powervalve is a device fitted to 4 stroke engines that constantly adjusts the internal diameter of the exhaust system to perfectly suit engine revolutions.

This ensures superior low to mid-range performance (ca. 12-20% improvement), linear power output and reduced exhaust noise levels while the valve is in its reduced opening position.

* Yamaha EXUP (Exhaust Ultimate Power valve)
* Honda HTEV (Honda Titanium Exhaust Valve)
* Suzuki SET (Suzuki Exhaust Tuning)

The Gerotor

A Gerotor is a positive displacement pumping unit. The name gerotor is derived from "Generated Rotor". A Gerotor unit consists of an inner and outer rotor. The inner rotor has N teeth, and the outer rotor has N+1 teeth. One rotor is located off-center and both rotors rotate. During part of the assembly's rotation cycle, the area between the inner and outer rotor increases, creating a vacuum. This vacuum creates suction, and hence, this part of the cycle is where the intake is located. Then, the area between the rotors decreases, causing compression. During this compression period, fluids can be pumped, or compressed (if they are gasseous fluids).

A gerotor can also function as a motor. High pressure gas enters the intake area and pushes against the inner and outer rotors, causing both to rotate as the area between the inner and outer rotor increases. During the compression period, the exhaust is pumped out. This is an Otto cycle engine.

An engine created by the Starrotor Corporation combines both uses of a gerotor. It uses the Brayton cycle, the same thermodynamic cycle employed by jet engines. A first gerotor compresses gas, this gas is then ignited in a combustor. The gaseous products of this combustion have a much higher pressure, which drives a second gerotor. Then, some of the output of the second gerotor is used to drive the 1st.

Longitudinal engine

In automotive engineering, a longitudinal engine, also sometimes known as a north-south engine, is an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, front to back. Most rear wheel drive vehicles use this engine orientation, while most front wheel drive vehicles use a side-to-side transverse arrangement. An exception is most Audi vehicles (those not using Volkswagen-based platforms) which continue to use the longitudinal layout even with larger displacement engines.

A common example of a longitudinal engine is the Boxer engine. This is a design where the cylinders are horizontally opposed, or facing each other. Common cars that share this design are: Alfa Romeo Alfasud (Flat-4), Alfa Romeo 145/146 (Flat-4), the Subaru Impreza (Flat-4) and the Porsche Boxster (Flat-6).

Air start system

The air start system on a large slow speed diesel engine is used to initiate ignition and consists of the following components: a compressor, an air reservoir (large cylindrical tank), associated piping, a control valve (this is linked to the camshaft), and the air start valves.

When starting the engine, compressed air is admitted to whichever cylinder has a piston just over top dead center, forcing it downward. As the engine starts to turn the air start valve on the next cylinder in line opens to continue the rotation. As this goes on, fuel is injected into the cylinders, the engine is then under way and the air is cut off.

To further complicate matters, a large engine is usually "blown over" first with zero fuel settings and the indicator cocks open, to prove that the engine is clear of any water build up and that everything is free to turn. After a successful blow ahead and a blow astern, the indicator cocks are closed on all the cylinders, and then the engine can be started on fuel.

Compared to a gasoline (petrol) engine, diesels have very high compression ratios to provide for reliable and complete ignition of the fuel without spark plugs. An electric starter powerful enough to turn a large diesel engine would itself be so large as to be impractical, thus the need for an alternative system.

Hydrogen fuel injection

Hydrogen Fuel Injection, or HFI, is a system to reduce exhaust emissions of internal combustion engines and improve fuel economy. HFI systems work by injecting hydrogen as a combustion enhancement into the intake manifold of an internal combustion engine to achieve these benefits. A small amount of hydrogen added to the intake air-fuel charge enhances the flame velocity and thus permits the engine to operate with leaner air-to-fuel mixture than otherwise possible. The result is lower pollution with more power and better mileage.

A simplified single-step combustion reaction is represented as: [FUEL] + [HYDROGEN] + [AIR] -> HC + CO + CO2 + H2O + NOx

For incomplete combustion, the above results in exhaust products including unburned hydrocarbons (HC) and carbon monoxide (CO). The NOx is formed mainly from the combustion air, and is highly temperature-dependent.

In 1974 John Houseman and D.J Cerini of the Jet Propulsion Laboratory, California Institute of Technology produced a report for the Society of Automotive Engineers entitled "On-Board Hydrogen Generator for a Partial Hydrogen Injection Internal Combustion Engine". In the same year, F.W. Hoehn and M.W. Dowy, also of the Jet Propulsion Lab, prepared a report for the 9th Intersociety Energy Conversion Engineering Conference, entitled "Feasibility Demonstration of a Road Vehicle Fueled with Hydrogen Enriched Gasoline." This research utilized onboard storage tanks to supply the hydrogen combustion enhancement.

More recent investigations have highlighted the potential for pollutant reduction. Research performed by scientists at the University of Birmingham, United Kingdom, released a study in June of 1995 at the HYPOTHESIS Conference at the University of Cassino, Italy in which it was presented that "hydrogen, when used as a fractional additive at extreme lean engine operation, yields benefits in improved combustion stability and reduced nitrogen oxides and hydrocarbon emissions." Similar results have been presented by a team of scientists representing the Department of Energy Engineering, Zhejiang University, China in the Spring of 1997 at an international conference held by the University of Calgary. Practical tests have been performed by California Environmental Engineering (CEE), The American Hydrogen Association Test Lab and Corrections Canada in which reduction in toxic exhaust emissions and fuel consumption were realized.

Commercially, Canadian Hydrogen Energy Company, LTD, produces an HFI system which generates hydrogen during vehicle operation by electrolyzing water (from an onboard storage tank) using power from the vehicle's electrical system. In dynamometer tests with 1992 60 series diesel engine fueled by low-sulphur (<15 PPM) diesel fuel, the system draws a maximum of 35 amps (12V DC) and yields 4.44% reduced fuel consumption, 6.17% reduced HC emissions, 0.39% reduces CO emissions, 4.34% reduced NOx emissions, and 7.0% reduced PM (particulate matter) emissions.

Publicly, Canadian Eagle Research Company produces the HyZor on-board electrolyzer that is comparable to coexisting commercial devices primarily being scaled down to fit Sedans, Coupes, SUV's, and Hybrids. A unique feature of the system is its design not to remove oxygen giving the output gas properties extremely similar to the HFI system while eliminating the required ducting components necessary to separate oxygen. These systems are fully automated only requiring occasional refills of distilled water when the system informs the driver by dash mounted led’s controlled by an electronic circuit integrated with the vehicles ignition.

Capacitor discharge ignition

Capacitor discharge ignition (CDI) is a type of automotive electronic ignition system which is widely used in motorcycles, lawn mowers, chain saws, small engines and recently in some cars. Capacitor discharge ignition uses capacitor discharge current output to fire the spark plugs.


The basic principle

Most of typical ignition system used in cars are inductive ignition system, which is solely relying on the electric inductance at the coil to produce high-voltage electricity to the spark plugs. In a CDI system, the system charges a capacitor by default, and during the ignition point the system stopps charging the capacitor, allowing the capacitor to discharge its output to the final coil before reaching the spark plug.

A typical CDI module may consist of a small transformer, a charging circuit, a triggering circuit and a main capacitor. Firstly, the system voltage is raised up to 400 V by a transformer inside the CDI module. Then, the electric current flows to the charging circuit and charges the capacitor. The rectifier inside the charging circuit prevents capacitor discharge before the ignition point.

When the triggering circuit receives triggering signals from triggering devices such as Hall effect sensor or pulse generator during the ignition point, the triggering circuit stops the operation of the charging circuit, allowing the capacitor to discharge its output rapidly to the ignition coil. The rapid capacitor discharge then produces a very high voltage at about 40 kV to be fired at the spark plug. When there's no triggering signal, the charging circuit is re-connected to charge back the capacitor.


CDI modules can be generally divided into two:-

* AC-CDI - The AC-CDI module obtains its electricity source solely from the alternating current produced by the alternator. The AC-CDI system is the most basic CDI system which is widely used in small engines.
* DC-CDI - The DC-CDI module is powered by the battery, and therefore an additional DC/DC inverter circuit is included in the CDI module to raise the 12 V DC to 400 V DC, making the CDI module slightly larger. However, the vehicle that uses DC-CDI system has more precise ignition timing and the engine can be started easier when cold.


Advantages and Disadvantages of CDI

CDI system produces higher ignition voltage (about 40 kV) compared with typical inductive ignition system (about 20 kV). The higher voltage produced by the CDI system produces a hotter spark, enabling the engine to be operated even with badly-fouled spark plugs.

The CDI system also has a faster voltage rise time (between 3 ~ 10 kV/μs) compared with typical inductive systems (300 ~ 500 V/μs). The higher voltage rise time results in a shorter spark duration with the CDI system (10 ~ 12 μs) and therefore the spark output is more accurate.

However, the shorter spark duration means the CDI system is not suitable for sharing between cylinders in multi-cylinder engines. It was not until the end of the 1990s that CDI system could be practically used in multi-cylinder engines, especially in cars, as a result of the development of the direct ignition system, where each cylinder has its own ignition coil.

CDI systems also have problems with lean air-fuel mixture and high compression engines as well as cold-starting problems. However, the problems can be solved by using waste-spark methods.


History

THe history of capacitor discharge ignition system can be traced back in 1950s together with the development of other electronic ignition systems. The first commercial motorcycle using the CDI system was manufactured by Kawasaki.

By the end of 1960s, the US government made new laws enforcing strict emission standards. As a result, more and more electronic ignition systems were developed, and starting from 1970s all smaller engines installed CDI system to replace the contact point system, including Honda Cub which began to use AC-CDI system.

By the end of 1990s, direct ignition system using capacitor discharge ignition system was developed and started to be installed on some newer car models.

Hypereutectic piston

“Hypereutectic” means “Over” eutectic. The word eutectic refers to a condition in chemistry when two elements can be alloyed together on a molecular level, but only up to a specific percentage, at which point any additional secondary element will retain a distinct separate form.

Although internal combustion engine pistons commonly contain trace amounts (less than 2% each) of Copper, Manganese, and Nickel, the major element in automotive pistons is Aluminum due to its light weight, low cost, and acceptable strength. The alloying element of concern in automotive pistons is Silicon. Gold and Silver have no eutectic point, which means they can be alloyed together in any ratio. However, when Silicon is added to Aluminum they will only blend together evenly on a molecular level up to approximately a 12% Silicon content. For the purposes of this discussion, Silicon in this context can be thought of as “powdered sand”, and any Silicon that is added to aluminum at above a 12% content will retain a distinct granular form instead of melting. At a blend of 25% Silicon, there is a significant reduction of strength in the piston alloy, so stock hypereutectic pistons commonly use a level of Silicon between 16% and 19%. Special molds, casting, and cooling techniques are required to obtain uniformly dispersed silicon particles throughout the piston material.


The reason for their development

Most automotive engines use aluminum pistons that cycle in a steel cylinder. The average temperature of a piston crown in a gasoline engine during normal operation is typically about 600 degrees Fahrenheit, and the coolant that runs through the engine block is usually regulated at approximately 190 degrees F. Aluminum expands more than steel at this temperature range, so for the piston to fit the cylinder properly when at a normal operating temperature, the piston must have a loose fit when cold.

In the 1970’s, increasing concern over exhaust pollution caused the U.S. government to form the Environmental Protection Agency (EPA) which began passing legislation that forced auto manufacturers to make changes that allowed their engines to run cleaner. By the late 1980’s, auto exhaust pollution had been noticeably improved, but increasingly stringent regulations forced car manufacturers to adopt the use of electronically controlled fuel injection and hypereutectic pistons. It was discovered that when an engine is cold, a small amount of excess fuel during start-up became trapped between the piston rings. This admittedly small quantity of excess fuel affected the amount of hydrocarbons in the exhaust when the piston expanded as it warmed, and then expelled the excess fuel.

By adding Silicon to the pistons alloy, the amount the piston expanded could be dramatically reduced, which allowed engineers to specify a much tighter cold-fit. Silicon itself expands less than Aluminum, and it also acts as an insulator to prevent the Aluminum from absorbing as much of the operational heat as it otherwise would. Another beneficial effect of adding Silicon is that the piston becomes harder, and is less susceptible to scuffing, which can occur when a soft aluminum piston is cold-revved in a relatively dry cylinder on start-up.

The biggest drawback of piston Silicon is that the piston becomes more brittle as more Silicon is added, which allows the piston to develop cracks easier if the engine experiences pre-ignition or detonation.


Performance replacement alloys

When an auto enthusiast wants to increase the power of their engine, they often add some type of forced induction. By compressing more air and fuel into each intake cycle, the power of the engine can be dramatically increased. This also increases the heat and pressure in the cylinder.

The normal temperature of gasoline engine exhaust is approximately 1200 F. This is also approximately the melting point of most Aluminum alloys, and it is only the constant influx of ambient air that prevents the piston from deforming and failing due to excess temperatures. Forced induction increases the operating temperatures while “under boost”, and if the excess heat is added faster than engine can shed it, the elevated cylinder temperatures will cause the air and fuel mix to auto-ignite on the compression stroke before the spark event. This is one type of engine knocking that causes a sudden shock wave and pressure spike, which can result in an immediate and catastrophic failure of the piston and connecting rod.

The “4032” performance piston alloy has an approximate Silicon content of 11%. This means that it expands from heat less than a piston with no Silicon, but since its eutectic level of Silicon is fully alloyed on a molecular level, this alloy is less brittle and more flexible than a stock Hypereutectic “smog” piston. These pistons can survive mild detonation with less damage than stock pistons.

The “2618” performance piston alloy has less than 2% Silicon and could be described as Hypo (under) eutectic. This alloy is capable of experiencing the most detonation and abuse while suffering the least amount of damage. Pistons made of this alloy are also typically made thicker and heavier because of their most common applications. Because of the higher than normal temperatures these pistons experience in their usual application, and also the low-Silicon content allowing the maximum possible Aluminum heat-expansion, these pistons have their cylinders bored to a very loose cold-fit. This leads to a condition known as “piston slap” which is when the piston rocks in the cylinder, and it causes an audible tapping noise that continues until the engine has warmed to operational temperatures. These engines should not be revved when cold, or excessive scuffing can occur.


Forged versus Cast

When a piston is cast, the alloy is heated until it is a liquid, and then it is poured into a mold to create its basic shape. After the alloy cools and solidifies, it is removed from the mold, and then the rough casting is machined to its final shape. When a piston is desired that is stronger than what simple casting can provide, they can be forged. This is when the rough casting is placed in a die set while it is still hot, and a hydraulic press is used to place the rough slug under a tremendous amount of pressure. This removes any possible porosity and also pushes the alloy grains together tighter than what can be achieved by simple casting alone, resulting in a much stronger material.

Hypereutectic pistons can be forged, but typically are only cast. This is because cast pistons are considered strong enough for stock applications, and the extra expense is not justified.

Aftermarket performance pistons made from the most common 4032 and 2618 alloys that are often used to replace stock hypereutectic pistons are typically forged.

Hot tube engine

The hot tube engine is a relative of the hot bulb engine with better timing control. The hot bulb engine only ran well at one speed- and a low one at that, typically 100 RPM. The timing of a hot tube engine is controlled by means of varying the length of the Hot-tube ignitor, which is longer and thinner than the hot bulb on a hot bulb engine. Length of the tube controls when the charge ignites, and allows different operating speeds to be selected. If made variable, this makes for adjustable engine speed, but also induces a mechanical weakness in the engine which tends to lead to failure. Both engine types are now replaced by diesels, which can be made to operate over varying loads and speeds in any size with modern methods. Hot bulbs are still used in remote areas where the extreme fuel flexibility is a major advantage. Hot tube engines may also be found there, if their difficulties with the adjustable tube can be overcome, or accepted and lived with.

Forced induction

Forced induction is a term used to describe internal combustion engines that are not naturally aspirated. Instead, a gas compressor is added to the air intake, thereby increasing the quantity of oxygen available for combustion. This compressed air is normally referred to as Boost or charge air.


Introduction

Forced induction can be used to increase the power of an engine or its efficiency, or both, without much extra weight. The ambient air that the engine is normally ingesting enters the compressor inlet of turbocharger or supercharger that is inline along the air intake tract. This effectively increases the pressure and density of the air, which allows for a much greater percentage of oxygen per volume of air intake to be added to the air/fuel mixture. The effects are an increase to the effective capacity of the engine without an increase in physical size. The forced induction approach has the advantage that the intake pressure may be regulated according to the engine speed, thus providing power from extra capacity at high speed, but without wasting fuel at lower speeds. A Nitrous Oxide system is also a form of forced induction. A simple oxidizer is injected either directly (direct port) or by a single fogger...with fuel(wet nitrous system) or without fuel(dry nitrous system).

Two of the commonly used forced induction technologies are turbochargers and superchargers. They differ mainly in the power source for the compressor. Turbochargers are driven by the exhaust gases of the engine, whereas superchargers are driven by a geartrain or belt connected to the crankshaft of the engine.


Comparison

Strengths and weaknesses vary according to the method of forcing induction largely based upon the inherent design functions of both. A turbocharger acts as an obstacle to exhaust gases due to its placement in the exhaust system tract. A supercharger uses torque generated from the rotational mass internal to the engine through the crank pulley. A turbo relies on the volume and velocity of exhaust gases to spool, or spin the turbine wheel. The turbine wheel is connected to the compressor wheel via a common shaft. The compressor wheel compresses the intake charge increasing the charge density by a large factor. The amount of time that it takes a turbocharger to reach the onset of boost is referred to as lag. A supercharger is 'on' all of the time, meaning that it is capable of producing a linear increase of boost up until redline. It is easier to target a desired boost with a turbocharger as there are many forms of boost controllers that allow a user to adjust to desired boost fairly easily. In order to achieve desired boost with a supercharger, a larger or smaller pulley must be installed.


Intercooling

A fundamental principle to forced induction is that compressing air raises its temperature. As a result, the charge density is reduced and the cylinders receive less fresh air than the system’s boost pressure prescribes. The risk of pre-ignition or "knock" in internal combustion engines greatly increases. These drawbacks are countered by charge-air cooling, which passes the air leaving the turbocharger or supercharger through a heat exchanger typically called an intercooler. This is done by cooling the charge air with an ambient flow of either air (air-air intercoolers) or liquid (liquid to air intercoolers), the charge air density is increased and the temperature is reduced.


Alcohol/Water Injection

Additionally, alcohol injection is an effective means of cooling the charge air. Methanol is the preferred alcohol due to its elemental properties, and is normally mixed with water to prevent evaporation. Methanol is typically injected pre throttle body. Methanol, unlike nitrous oxide or forced induction itself, doesn't add more oxygen to the charge, but by its low evaporation point changes from a liquid to a gas as its introduced into the air charge. The evaporation process uses the heat from the intake charge to complete the phase change. The alcohol is also a fuel in the charge which will cause a rich condition if used in excess. Due to the lower intake temperatures and denser air charge more power is exerted from the engine. Methanol is typically used in conjunction with poor quality fuel(pump gas) in order to run higher than normal boost pressures.

Like was stated above, adding forced induction increases the amount of air an engine can use for combustion, in effect allowing more fuel to be used with the available oxygen. Further, it increases an engine's dynamic compression ratio. As compression ratio increases, so does the threat of knock and therefore the need for higher octane fuel.

Hybrid Synergy Drive

Hybrid Synergy Drive, (HSD) is a set of hybrid car technologies developed by Toyota and used in that company's Prius, Highlander Hybrid, Camry Hybrid, Lexus RX 400h, and Lexus GS 450h automobiles. In 2008, the Corolla will also have a HSD hybrid version. It combines the characteristics of an electric drive and a continuously variable transmission, using electricity and transistors in place of toothed gears. The Synergy Drive is a drive-by-wire system with no direct mechanical connection between the engine and the engine controls: both the gas pedal and the gearshift lever in an HSD car merely send electrical signals to a control computer.

HSD is a refinement of the original Toyota Hybrid System (THS) used in the 1997–2003 Toyota Prius. As such it is occasionally referred to as THS II. The name was changed in anticipation of its use in vehicles outside the Toyota brand (Lexus; the HSD systems used in Lexus vehicles have since been termed Lexus Hybrid Drive since 2006).

When required to classify the transmission type of an HSD vehicle (such as in standard specification lists or for regulatory purposes), Toyota describes HSD-equipped vehicles as having E-CVT (Electronically-controlled Continuously Variable Transmission).

General Motors and DaimlerChrysler's Global Hybrid Cooperation is similar in that it combines the power from a single engine and two motors. In contrast, Honda's Integrated Motor Assist uses a more traditional ICE and transmission where the flywheel is replaced with an electric motor.

Some early non-production Plug-in hybrid electric vehicle conversions have been based on the version of HSD found in the 2004 and 2005 model year Prius. Early Pba conversions by CalCars have demonstrated 10 miles of ev-only and 20 miles of double mileage mixed-mode range. A company planning to offer conversions to consumers named EDrive systems will be using Valence Li-ion batteries and have 35 miles of electric range. Both of these systems leave the existing HSD system mostly unchanged and could be similarly applied to other hybrid powertrain flavors by simply replacing the stock NiMH batteries with a higher capacity battery pack and of course a charger to refill them for about $0.03 per mile from standard household outlets. Another provider of a plug-in module for the Toyota Prius is Hymotion.



Phases of operation

The HSD operates in distinct phases depending on speed and demanded torque. Here are a few of them:

* Engine start: The vehicle launch is done in all-electric mode. The engine starts once a limiting speed in the generator is reached. At the engine cut-in point, MG1 is fed negative voltage, so that it acts as a starter motor. The engine is forced into forward motion. Because both motor generators are sized to drive the entire car, turning the engine does not stress the motors and the conventional starter motor sound is not heard: engine start is silent.

* Low gear (equivalent): When accelerating at low speeds in normal operation, the engine turns much more rapidly than the wheels, but does not develop as much torque as is needed. MG1 is forced rapidly backwards, and the computer pulls electricity from MG1. The electricity is shunted to MG2, adding torque at the driveshaft, so that the drive train develops power at low speed and high torque.

* High gear (equivalent): When cruising at high speed, the engine turns more slowly than the wheels, but develops more torque than is needed. The computer pulls electricity from MG2, reducing the torque available at the wheels. The electricity is shunted to MG1, which boosts the speed of the driveshaft. Because the engine supplies mechanical energy to the whole system, conservation of energy is not violated: the power that is shunted from MG2 to MG1 is less than the total power developed by the engine, and so power is delivered to the wheels.

* Reverse gear: There is no reverse gear as in a conventional gearbox: the computer feeds negative voltage to MG2, applying negative torque to the wheels. Early models did not supply enough torque for some situations: there have been reports of early Prius owners not being able to back the car up steep hills in San Francisco. The problem has been fixed in recent models. If the battery is low, the system can simultaneously run the engine and draw power from MG1, although this will reduce available reverse torque at the wheels.

* Silent operation: At slow speeds and moderate torques the HSD can drive without running the gasoline engine at all: electricity is supplied only to MG2, allowing MG1 to rotate freely (and thus decoupling the engine from the wheels). This is popularly known as "Stealth Mode." Provided that there is enough battery power, the car can be driven in this silent mode for some miles even without gasoline.

* Neutral gear: Most jurisdictions require automotive transmissions to have a neutral gear that decouples the engine and transmission. The HSD "neutral gear" is achieved by breaking the electrical connection to both MG1 and MG2. Under this condition, MG1 is free running and no torque can be delivered to the wheels (MG1 rotates backwards when the engine rotates forward).

* Regenerative braking: by drawing power from MG2 and depositing it into the battery pack, the HSD can simulate normal compression braking while saving the power for future boost. The HSD system has a special transmission setting labelled 'B' (for Brake), that takes the place of a conventional automatic transmission's 'L' setting for engine braking on hills. If the battery is full, the system switches to conventional compression braking, drawing power from MG2 and shunting it to MG1 to slow the speed of the engine. The regenerative brakes in a HSD system absorb a significant amount of the normal braking load, so the conventional brakes on HSD vehicles are undersized compared to brakes on a conventional car of similar mass.

* Electric boost: The battery pack provides a reservoir of energy that allows the computer to match the demand on the engine to a predetermined optimal load curve, rather than operating at the torque and speed demanded by the driver and road. The computer manages the energy level stored in the battery, so as to have capacity to absorb extra energy where needed or supply extra energy to boost engine power.

* Battery charging: The HSD can charge its battery without moving the car, by running the engine and extracting electrical power from MG1. The power gets shunted into the battery, and no torque is supplied to the wheels.




Performance

The Toyota Prius has decent, but not sport-car-like, acceleration but has extremely high mileage for a mid sized four-door sedan: 45 mpg (US) is typical of brief city jaunts; 55 mpg is not uncommon, especially for extended drives (which allow the engine to warm up fully). This is about twice the fuel efficiency of a similarly equipped four-door sedan with a conventional power train. Not all of the extra efficiency of the Prius is due to the HSD system: the Atkinson cycle engine itself was also designed specifically to minimize engine drag with an offset crankshaft to minimize piston drag during the power stroke, and a unique intake system to prevent drag caused by manifold vacuum versus the normal Otto cycle in most engines.

The Highlander Hybrid (also sold as the Kluger in some countries) offers better performance compared to its non-hybrid version. The hybrid version goes from 0–60 mph in 7.2 seconds, trimming almost a second off the conventional version's time. Net hp is 268 hp compared with to the conventional 215 hp. Top speed for all Highlanders are limited to 112 mph. Typical fuel economy for the Highlander rates between 27 and 31 mpg. A conventional Highlander is rated by the EPA with 19 city, 25 highway mpg.

Ford Motor Company licensed HSD technology in 2004 and it is currently offered in an SUV, the Ford Escape, though a hybrid Ford Fusion will be released in the future. The four-cylinder hybrid Escape achieves an impressive increase in mileage, to 28–32 mpg.

There have been reports in the press of hybrid power trains not living up to fuel efficiency claims. This is due in part to the sensitivity of hybrid mileage to driving style. The mileage boost depends on using the gasoline engine as efficiently as possible, which requires:

* extended drives, especially in winter: Heating the internal cabin for the passengers runs counter to the design of the HSD. The HSD is designed to generate as little waste heat as possible. In a conventional car, this waste heat in winter is usually used to heat the internal cabin. In the Prius, running the heater will the require the engine to continue running to generate cabin-usable heat. This effect is most pronounced by turning the climate control (heater) off when at a stop when the engine is running. Normally the HSD control system will shut the engine off as it is not needed, and will not start it again until the generator reaches a maximum speed.

* moderate acceleration: Because hybrid cars can throttle back or completely shut off the engine during moderate, but not rapid, acceleration, they are more sensitive than conventional cars to driving style. Hard acceleration forces the engine into a high-power state while moderate acceleration keeps the engine in a lower power, high efficiency state (augmented by battery boost).

* gradual braking: Regenerative brakes re-use the energy of braking, but cannot absorb energy as fast as conventional brakes. Gradual braking recovers energy for re-use, boosting mileage; hard braking wastes the energy as heat, just as for a conventional car

Most HSD systems have batteries that are sized for maximal boost during a single acceleration from zero to the top speed of the vehicle; if there is more demand, the battery can be completely exhausted, so that this extra torque boost is not available. Then the system reverts to just the power available from the engine. This is a big difference in performance: an early-model Prius can achieve over 90 mph on a 6 degree upward slope, but after about 2,000 feet of altitude climb the battery is exhausted and the car can only achieve 55–60 mph on the same slope (until the battery is recharged by driving under less demanding circumstances).

Short Long Arms Suspension

An SLA is also known as an unequal length double wishbone suspension. The upper arm is typically an A-arm, and is shorter than the lower link, which is an A-arm or an L-arm, or sometimes a pair of tension/compression arms. In the latter case the suspension can be called a multi-link, or Dual ball joint suspension.

The four bar link mechanism formed by the unequal arm lengths causes a change in the camber of the vehicle as it rolls, which helps to keep the contact patch square on the ground, increasing the ultimate cornering capacity of the vehicle. It also reduces the wear of the outer edge of the tire.

SLAs can be classified as short spindle, in which the upper ball joint on the spindle is inside the wheel, or long spindle, in which the spindle tucks around the tire and the upper ball joint sits above the tire.

Double wishbone suspension

In automobiles, a double wishbone (or "upper and lower A-arm") suspension is an independent suspension design using two parallel wishbone-shaped arms to locate the wheel. Each wishbone or arm has two mounting positions to the chassis and one joint at the knuckle. The shock absorber and coil spring mount to the wishbones to control vertical movement. Double wishbone designs allow the engineer to carefully control the motion of the wheel throughout suspension travel, controlling such parameters as camber angle, caster angle, toe pattern, roll center height, scrub radius, scuff and more.

The double wishbone suspension is also often referred to as double 'A' arm or short long arm (SLA) suspension. It is commonly used in sports cars, luxury cars and light trucks.

A single wishbones or A-arms are used in various other suspension types, such as MacPherson strut and Chapman strut.

The suspension consists of a pair of upper and lower lateral arms, roughly horizontal and of similar length. The upper arm is usually slightly shorter to induce more negative camber on the outside wheel as the vehicle body rolls in a turn. Between the arms there is a knuckle with a spindle or hub which carries the wheel bearing and wheel. Knuckles with an integral spindle usually do not allow the wheel to be driven. A bolt on hub design is commonly used if the wheel is to be driven.

In order to resist fore-aft loads such as acceleration and braking, the arms need two bushings or ball joints at the body.

At the knuckle end, single ball joints can be used, in which case the steering loads have to be taken via a steering arm, and the wishbones look A- or L-shaped. An L-shaped arm is generally preferred on passenger vehicles because it allows a better compromise of handling and comfort to be tuned in. The bushing in line with the wheel can be kept relatively stiff to effectively handle cornering loads while the offline joint can be softer to allow the wheel to recess under fore aft impact loads. For a rear suspension, a pair of joints can be used at both ends of the arm, making them more H-shaped in plain view.

In front view, the suspension is a 4-bar link, and it is easy to work out the camber gain (see camber angle) and other parameters for a given set of bush locations.

The various bushes do not have to be on horizontal axes, parallel to the vehicle centre line. If they are set at an angle, then antidive and antisquat can be dialled in.

The advantage of a double wishbone suspension is that it is fairly easy to work out the effect of moving each joint, so you can tune the kinematics of the suspension easily and optimize wheel motion. It is also easy to work out the loads that different parts will be subjected to which allows more optimized lightweight parts to be designed.

The disadvantage is that it is slightly more complex than other systems like a MacPherson strut.

SLAs are very common on front suspensions for larger cars, Pickups and SUV's and double wishbones are very common at both ends of racing cars.

Prior to the dominance of front wheel drive in the 1980s, many everyday cars used double wishbone front suspension systems, or a variation on it. Since that time, the MacPherson strut has become almost ubiquitous, as it is simpler and cheaper to manufacture. Double wishbones are usually considered to have superior dynamic characteristics, load handling capability and are still found on higher performance vehicles.

Digifant Engine Management system

The Digifant Engine Management system is an electronic fuel injection system designed by Volkswagen A.G. in cooperation with Robert Bosch GmbH.

Digifant is the outgrowth of the Digi-jet Fuel Injection system first used on early Vanagon vehicles.



History

Digifant was introduced in 1986 on the 2.1L Vanagon Engine. This system combined digital fuel control as used in the earlier Digi-Jet systems with a new digital ignition system. Digifant as used in Golf and Jetta models simplified several functions and added knock sensor control to the ignition system. Other versions of Digifant appeared on the Fox, Corrado, Eurovan as well as later production versions of the rear engined VW Beetle, sold only in Mexico.


Features

Fuel injection control is digital electronic. It is based on the measurement engine load (this signal is provided by the Air Flow Sensor), and on engine speed (Signal provided by the hall sender in the distributor). These primary signals are compared to a map, or table of values, stored in the Engine Control Module (ECM) memory.

The amount of fuel is controlled by the injector (duration). This value is taken from a program in the ECM that has 16 points for load and 16 points for speed. These 256 primary values are then modified by coolant temperature, intake air temperature, oxygen content of the exhaust, battery voltage and throttle position to provide 65,000 possible injector duration points.

Digifant is unlike the earlier CIS and CIS-E fuel injection systems that it replaced in that fuel injectors are mounted on a common fuel rail. The fuel injectors are wired in parallel, and are supplied with Constant System Voltage. The ECM switches the Ground on and off to control duration. All injectors operate at the same time each crankshaft revolution; two complete revolutions being needed for each cylinder to receive the correct amount of fuel for each combustion cycle.

Ignition control is also digital electronic. The sensors that supply the engine load and engine speed signals for injector duration provide information about the basic ignition timing point. The signal sent to the Hall control unit is derived from a program in the ECM that is similar to the injector duration program.

There are 16 points available for load and 16 points for speed. The resulting 256 single operational points are modified by coolant temperature signals and cylinder selective knock control to achieve the optimal ignition point.

Knock control is used to allow the ignition timing to continually approach the point of detonation. This is the point where the engine will produce the most power, as well as the highest efficiency.

Additional functions of the ECM include operation of the fuel pump by closing the Ground for the fuel pump relay, and control of idle speed by a throttle plate bypass valve. The idle air control vale (previously known as an idle air stabilizer valve), receives a changing milliamp signal that varies the strength of an electro-magnet pulling open the bypass valve.

Idle speed stabilization is enhanced by a process known as Idle Speed Control (ISC). This function (previously known as Digital Idle Stabilization), allows the ECM to modify ignition timing at idle to further improve idle quality.



Inputs/Outputs - Digifant II

The 25 pin electronic control unit used in the Golf and Jetta receives inputs from the following sources:

- Hall Sending Unit (Provides Engine Speed Signal) - Air Flow Sensor (Provides Engine Load Information) - Coolant Temperature Sensor - Intake Air Temperature Sensor - Knock Sensor

Additional signals used as inputs are:

- Air Conditioner (compressor on) - Battery Voltage - Starter Signal

The anti-lock brake system, 3-speed automatic transmission and vehicle speed sensor are not linked to this system.

Outputs controlling engine operation include signals to the following:

- Fuel Injectors - Idle air control valve - Hall Control Unit - Fuel Pump Relay - Oxygen Sensor Heater



Additional Systems

The evaporative emission system is controlled by a vacuum operated mechanical carbon canister control valve.

Fuel pressure is maintained by a vacuum operated mechanical fuel pressure regulator on the fuel injector rail assembly.

Inputs and outputs are shown in the following illustration. Digifant II as used on Golf and Jetta vehicles provides the basis for this chart.



System Variants (North America Only)

In North America, Volkswagen released two versions of the Digifant Fuel Injection system. Note that this refers to A2 Golf and Jetta models only.

Digifant I was used exclusively in California market vehicles. Primary differences between Digifant I and Digifant II are as follows:

A limited number of 1987-1990 California Golf and Jetta models are equipped with an On Board Diagnostics system (OBD). These vehicles have blink code capacity to store up to 5 Diagnostic Trouble Codes (DTCs). For the most part, diagnostic troubleshooting is done with a Volkswagen special tool, known as the VAG 1598 and a Digital Multimeter. This system can also have carbon monoxide (CO), ignition timing and idle speed adjusted to baseline values.

In 1991, California Golf, Jetta, Fox, Cabriolet and Corrado vehicles were equipped with expanded OBD capabilities. These later Digifant versions have 38-pin ECMs with Rapid Data Transfer and permanent DTC memory. All Eurovans with Digifant also have rapid data transfer and permanent DTC memory. These systems use a throttle plate potentiometer to track throttle plate position in place of the idle and full throttle switches used on earlier systems.

Another characteristic of Digifant 1 equipped vehicles is a switch mount on the dashboard which has a "Check Engine" symbol.


Summary

Digifant is an engine management system designed originally to take advantage of the first generation of newly developed digital signal processing circuits. Production changes and updates were made to keep the system current with the changing California and federal emissions requirements. Updates were also made to allow integration of other vehicle systems into the scope of engine operation.

Changes in circuit technology, design and processing speed along with evolving emissions standards, resulted in the development of new engine management systems. These new system incorporated adaptive learning, enhanced and expanded diagnostics, and the ability to meet total vehicle emissions standards.



Maintenance of older Digifant Vehicles

In Volkswagen circles, Digifant has often been criticized for it's lack of performance tuning and occasional driveability issues. Most of these issues can be traced back to one of two issues:

- Bad ECM grounds - Faulty Engine Coolant Temperature Sensor (ECT)

The engine coolant temp sensor is located in the coolant flange on the front of the cylinder head.

In the following picture the Digifant Coolant Temperature sensor is clearly visible, as it is identified by a blue electrical connector.


Common issues that are indicative of a failed ECT are:

- Vehicle idles poorly - Engine sputters, might stall - Higher than normal fuel consumption

The part number for this sensor is 025-906-041-A (Always check with your dealer for the most updated part number).

When replacing this sensor, it is important to also replace the clip that holds it in position (032-121-142) and the O-Ring (N-903-168-02).

Once the new sensor has been installed, start the engine and disconnect the blue coolant temperature sensor. Rev the engine through 3000 RPM 3 times, each time allowing the throttle to close completely. This clears the Digifant ECM fault memory.

Twincharger

A twincharger is the denomination by the Volkswagen Group of a combination of a turbocharger and a supercharger in an engine. The 1.4 L TSI engine used in some current automobiles like the Volkswagen Golf, Touran employs both methods of forced induction, with the supercharger boosting low-end power while the turbocharger takes over at the high end. VW family of TSI engines also employs Fuel Stratified Injection.

The concept of a twincharger was pioneered by Lancia in the 1980s on the Delta S4 rally car and picked up by Nissan in the March compact car. In addition multiple aftermarket companies have made twincharger kits for cars like the Subaru Impreza WRX, Mini Cooper Type S, Skyline GT-R, Toyota MR-2, etc.

The most common type of twincharging system is a Roots type supercharger paired up with a medium-large sized turbocharger. The supercharger will give better power at low RPM while the turbocharger will give better power at medium-high RPMs. The main drawback of this configuration is that at high speeds, the supercharger (as it is driven by belts) will increase drag upon the engine, limiting the top end power. The Volkswagen Twincharging System overcomes this by locating the supercharger's pulley on a clutch system, which is automatically engaged and disengaged by the computer. This allows the car to keep its top-end performance and automatically switch to supercharging at low RPM.


Drawbacks

There are a few drawbacks to this setup, such as the supercharger still creates drag in the airflow system, even when the clutch is off and the turbocharger is on. It can also cause excessive pulley/belt wear as the clutch engages/disengages at usually very high engine speeds. The transition from the supercharger engaging/disengaging can also be quite rough as well. Lastly, as turbos continue to flow more air as engine speed rises, the turbocharger will eventually outflow more air than it is receiving from the supercharger unless complex piping is used to bypass which can be quite costly and inefficient in a small engine bay.


Solution

The solution to these problems is quite simple, switch the places of both force induction units. By having a turbocharger feed air into a supercharger you gain several benefits as well as minimize any drawbacks from a conventional twincharger setup. The benefits are quite obvious, the supercharger will generate a set amount of boost (determined by pulley size) almost instantly, thus causing the engine to create more exhaust flow and spin the larger turbo quicker. As engine speeds start reaching past the superchargers efficiency under normal circumstances, the turbocharger is providing increasing amounts of air to the supercharger where it would normally run out. All pressure the supercharger receives from the turbocharger is further compressed by whatever the supercharger pulley is rated for. This helps reduce drag on the engine and top speed restrictions isn't as limited.

Simply put, the twincharger concept is a cheaper alternative to the high cost of Nitrous used in many race cars as it provides the instant power without excessive re-filling cost. The twincharger concept itself has not been used on many production cars simply due to the complexity and cost of implementing this system on a vehicle. Another reason simply put is the concept itself is really only viable on sports cars with relatively small displacement engines with high revving capabilities. The main purpose of twincharging is to provide a broad power band, in which the vehicle would perform in just about any RPM speed. This concept is relatively pointless on V8 engines or any vehicles with high torque in stock form as they already possess broad power bands.


Twincharger Vs. Anti-Lag System

Twincharging's biggest benefit over Anti-Lag Systems now being employed in quite a few race cars is the amount of power and reliability it provides. Anti-Lag Systems depend on excessive engine misfiring to keep the turbochargers spooled and thus to maintain the vehicles optimal powerband. Excessive misfiring will cause excessive heat and damage to the turbo manifolds, turbochargers as well as damaging the engine. Anti-Lag Systems make passing Emissions testing next to impossible due to the excessive heat damaging the catalytic converters as well, the Twincharger system does not rely on misfiring at all thus increasing longevity. There are several things such as fuel economy, etc. that are severely compromised.


Other solution

The simplified blow-through system as defined above where the turbocharger feeds the supercharger is inherently flawed as of course the overall airflow is still defined by the rated flow of the supercharger itself, negating any benefits of using the supercharger as the means of purely boosting low engine speed air flow, as it restricts the top end air flow to the same magnitude. A purely supercharged engine would be more efficient. There will be some increases in the SC flow as the air fed to it by the TC becomes more pressurised, but the returns are diminishing and efficiency is reduced.

All systems utilising the twincharging method have a bypass valve that is electronically controlled. At a certain boost and engine speed, the supercharger is bypassed allowing all air to flow past it rather than through it, dedicating the high-flow, high-boost top end power duties to airflow through the turbocharger. The twincharge (or compound charge) systems of today rely heavily on an empirical method where load sites, speeds and airflow characteristics are mapped onto the ecu, which then controls a) the SC bypass valve, and b) the SC clutch. This method can be understood to be not unlike normal engine mapping where fuel and ignition timing are mapped to similar parameters, stored in lookup tables on the ecu, then read and outputted according to what the engine sensors are reading.

As a purely mechanical system, both blow through and suck through systems have their drawbacks when designing a suitable method of transition between the two modes. Historically, compound charged systems relied on the SC blowing into the TC, then when the TC was sucking on the SC hard enough to create a vacuum before the TC intake, a spring loaded valve placed before the TC would open allowing the extra air flow that the turbocharger reqested to be drawn around the SC instead of through it, whilst still using up the boost that the SC was providing. Similarly, the suck through method has a spring loaded valve placed after the turbo charger and before the supercharger, which would open and allow the TC to blow any extra pressurised air around the SC when the SC presented a restriction. These methods of system design are mechanicaly simple, but do not lend themselves to stop start driving where a no-boost moment can be experienced at partial throttle, when the useful boost in the intake escapes back past the partially open valve. It is however suited to cars that spend more time fully accelerating, as during a full bore gearchange the boost would be allowed to vent anyway.

NOx Adsorbers

The NOx Adsorber or NOx Trap is a device that is use to reduce NOx (NO and NO2) emissions from a lean burn internal combustion engine.


Purpose and Function of a NOx Adsorber

A NOx Adsorber is designed to reduce oxides of nitrogen emitted in the exhaust gas of a lean burn internal combustion engine. Lean burn (diesel) engines present a special challenge to emission control system designers because of the relatively high levels of O2 (atmospheric Oxygen) in the exhaust gas stream. The 3-Way Catalytic Converter technology