2009 Honda City

The all-new Honda City will make its European debut at the Istanbul Motor Show in October.

The compact sedan is a radical departure from the previous generation car, with a totally new exterior style, featuring some visual elements of the stylish Accord. The restyled exterior is joined by a new 1.4 i-VTEC engine, which gives the City significantly more power and better performance.

The new engine, which is also shared with the new Jazz is fitted with Honda's acclaimed i-VTEC system, which provides excellent performance and flexibility, without compromising fuel economy or emissions. The new engine gives the City 100PS, a healthy 17 PS increase over the previous model. This extra power helps the new City complete the benchmark 0-100 km/h in just 11.8 seconds for the manual version, an improvement of 1.6 seconds. The automatic version hits 100 in 14.7 seconds, almost half a second quicker than before.

The manual transmission for City is a modified version of the current gearbox, with carbon synchromesh for smoother changes, improved refinement and a new set of optimised gear ratios. The Automatic transmission is all-new and adds the option to shift gears with steering wheel mounted paddles for the first time. With a sport mode, improved shift logic and ratios the new transmission better compliments the new car's more powerful engine.

The all-new model has been further enhanced over its predecessor with a higher quality of materials, improved aesthetics and functionality. Increased storage capacity around the cabin including a bigger glove box improves practicality, while a new design of seats improves passenger and driver comfort.

The design changes are complimented by several improvements to the Noise Vibration and Harshness technologies applied to the car. A host of new features in the body, interior, suspension, engine and mountings have been included to bring further refinement to Honda's newest sedan. The NVH enhancements allow customers to make the most of the new audio system which offers iPod connectivity and better sound quality.

The New City is based on the platform of the award winning new Honda Jazz, and benefits from the many of the technologies seen in the new hatchback. The longer wheel base gives a significant improvement in interior space as well as the associated ride and handling benefits. Safety performance is also enhanced with the adoption of the ACE Body Structure (Advanced Compatibility Engineering), which better protects occupants of both cars in the event of a collision between vehicles of different heights.

The all-new City will go on sale from January in selected markets.

The new 2009 Audi A4

Stretching nearly five inches overall, more than two inches wider, and a six-inch-longer, the 2009 A4 is closing in on A6 dimensions (the wheelbase is 1.3 inches shorter). Being the largest in its class, nearly three inches longer than the C-Class and seven longer than the 3 Series sedan. With that increase in length and width and a minor reduction in height (making lower by less than 0.1 inch), the new model has a intergrated, sportier stance and holds the road with a new sense of confidence and enthusiasm.

Its new underpinnings are shared with the upcoming S5 and A5 coupes, and an A4 Avant will go on sale in the U.S. at the same time as the sedan. Like the A5/S5, the new A4 has sculpted lines, a more aggressive front end, and a row of LED daytime running lights underlining each headlamp. Thanks to the liberal use of ultra-high-strength steel, the body weighs 10 percent less than last year's, yet is more rigid. The side view is rather familiar-time will tell if this redesign was too conservative, especially compared with the aggressive lines of the new C-Class.


Audi A4 interior is completely redesigned, with high-quality materials and clean, attractive design continue to live up to Audi's stellar reputation. Black leather seats and matching black door panels contrasted nicely with patterned brushed aluminum accents. The redesigned center stack is easy to use, and MMI is now a part of the A4's layout -- we've heard it will be standard with the 3.2 (optional) optional. The cabin is larger in every dimension, front and rear seats are now more comfortable, and there's more rear-seat legroom than in the outgoing model. The trunk is bigger -- now 17.0 cubic feet, up from 13.4. Regardless, leather will be standard and should come in a choice of colors. Stereo options will include a choice of Bang & Olufsen stereo systems, including the excellent 14-speaker setup, plus a six-disc CD changer and iPod connectivity. In the cabin are more safety features: six airbags will be standard and rear-side airbags optional.

When the A4 goes on sale, it will initially be offered in quattro form only, with one engine and transmission –
a new 3.2-liter,
265-horsepower V-6 backed by a ZF six-speed automatic.

A second engine will follow -- expect an all-new 2.0T four and a manual and/or DSG with quattro as an option. The direct-injection V-6 uses Audi's two-stage valve-lift system, which makes more efficient use of the engine to improve fuel economy by six percent. The A4 gets to 62 mph in an estimated 6.2 seconds when backed by the manual, and the transmission's shifts are quick and easy to control with the steering-wheel-mounted paddles. And, through the reduced weight of the body, reduction in drag (down from a 0.31 Cd to approximately 0.29), and changes to the air conditioner (now 10 percent more powerful and the fuel consumption needed to run it has been reduced by 20 percent), fuel economy has improved.

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.

Audi R8, a very special sports coupe

The Audi R8's well proportioned design screams speed. The R8's leather-clad cockpit is spacious and well appointed. Even the R8's manual six-speed gear shifter is elegant. The European Audi R8 will also be the first production vehicle to feature all-LED headlights. The Audi R8 also features an optional Bang & Olufsen sound system.

2008 Audi R8
Type:
Mid-engine, all-wheel drive sports coupe

Retail price:
$109,000-$134,750

Engine:
4.2-liter V-8, 420-horsepower, 317-pound-feet torque

Transmission:
6-speed manual or automatic

EPA mileage
# Manual: 13 mpg city / 20 mpg highway
# Automatic: 13 city / 19 highway


Report card

Exterior: Excellent.
Smooth, sleek and bulletlike. Its wide stance and deceptively long body add to its intimidating exterior.

Interior: Excellent.
The seats hold you firmly in even the tightest of corners.

Safety: Excellent.
Front, knee and side air bags. Precise handling, stability control and anti-lock brakes.

Performance: Unbelievable.
Fast and furious.

Pros: Beautiful and beastly:
Will be noticed everywhere you go. Other super sports cars are often considerably more.

Cons:
Don't drive it to any Green Peace meetings. Powerful engine gobbles up fuel.

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.

2008 Audi TT coupe and convertible

The redesigned 2008 Audi TT coupe is longer, wider and faster.

2008 Audi TT coupe and convertible

Type:
A rear-wheel drive two-passenger convertible or 2+2 coupe.

Models:
Coupe (with 2+2 seating); Roadster (two-seater)

Retail price*:
$35,575 -- $50,000

Engines:
# 2-liter 4-cylinder turbo, 200 horsepower, 207-pound-feet torque;
# 3.2-liter V-6: 250-horsepower, 236-pound-feet torque

Transmission:
# 2-liter: six-speed automatic with sequential shifting.
# 3.2-liter: six-speed automatic with sequential shifting or six-speed manual.

EPA mileage

# 2-liter:
Coupe: 23 mpg / 31 mpg
Roadster:
22/29

# 3.2-liter (both types with automatic transmission):18/24

# 3.2-liter (both types with manual transmission): 17/24

Notes:
Expect a six-speed manual transmission to come with the 2-liter engine in the coming years
*Includes shipping


Performance:
Excellent. Engine is powerful for such a light vehicle. Optional sports tuned suspension package makes both vehicles a hoot to drive.

Exterior: Excellent.
Sleek lines and distinctive style maintain Audi's upscale character.

Interior: Excellent.
Luxury at your fingertips and flat bottom steering wheel makes it even feel different and special.

Safety: Excellent.
Front and side-curtain airbags as well as electronic stability control.

Pros:
It's comfortable and fun to drive; you'll never want to get to where you're going. The best deal is the coupe with the 2-liter engine.

Cons:
Cramped trunk space and steep price tag could keep the TT convertible from being a daily driver.

3.2 liter V-6 engine in the 2008 Audi TT produces 250 horsepower.

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).

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.

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 4A-GZE engine

The 4A-GZE (produced in various forms from 1986 through 1995) was the supercharged version. Based on the same block and head, the 4A-GZE was equipped with a roots-type supercharger and therefore the compression ratio, valve timing and ports were modified. It was used in the North American supercharged Toyota MR2, rated at 145 hp (108 kW) and 140 ft·lbf (190 N·m). Later versions of this engine are rated 170 hp (127 kW) and 155 ft·lbf (210 N·m) for the AE92 and AE101 Corolla.


4A-GE (20-valve)

A special 4A-GE was produced from 1991 through 1998 to replace the 16 valve 4A-GE. It was a naturally-aspirated engine with an additional intake valve for each cylinder, making it one of the first production 5-valve engines in history. These generation engines also featured quad throttle bodies. The engine can be recognized by its silver or black top. This was the last of the 4A family to be produced. Toyota VVT was used for 160–165 hp (123–127 kW) at 7800 rpm and 120 ft·lbf (162 N·m) at 5600 rpm, quite impressive for a naturally-aspirated 1.6 L engine. Note that although VVT was present in the silver top and the black top 4A-GE, VVT-i was not available.

Some Racing team participating in the Group A of the JGTC, using either the AE101, AE86 or AE82 corollas used modified silvertop versions of the engine, capable of approximately 240 Horsepowers at 11,000 RPM. The AE86 was particuraly popular, being able to beat cars with bigger engine such as the skyline.

Applications:

* 1992 Toyota Corolla Levin, Sprinter Trueno AE101 (silver-top) All GT models (GT Apex GT-V etc)

* 1995 Toyota Corolla Levin, Sprinter Trueno AE111 (black-top) All BZ models (BZG, BZR, BZV etc)

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.

Hybrid Cars

The hybrid version of automobiles offers the customer an interesting assortment of engine features that are supplemented with power options through the use of electrical motor and battery participation. These engine features are not available in every hybrid automobile currently being sold at automobile dealerships or through private sales in society today. The hybrid engines are equipped with gas powered, or dual powered engines, as well as an electrical motor that renders power support when needed. There is a heavy duty battery that serves as a source of power as well.

Within the hybrid breed of automobile engine varieties, there is a mild hybrid category and a full hybrid category. While each of these categories contain the same equipment, the performance of that installed equipment can cause your automobile to operate on entirely different principles. The mild hybrid category consists of a gas powered automobile engine that serves as the propulsion mechanism to move your automobile down the street.

Paired with this gas powered automobile engine is an electrical motor, as well as a heavy duty battery that are snuggly connected throughout the engine maze of pipes and mechanisms that when energized can provide propulsion to move your automobile forward. The hybrid car engine is the only source of propulsion power in the mild hybrid engine model, and the electrical motor remains in standby mode to provide spurts of energy and power to aid the gas powered engine in passing vehicles on a highway or wherever else a sudden surge of power will be of benefit.

The full hybrid category consists of a gas powered automobile engine that is considered the propulsion mechanism as well as an energy saving device. An electrical motor and a heavy duty battery are also part of this full hybrid engine power force. The gas powered engine works hand in hand with the electrical motor to provide the necessary boosts of energy to cause the car to propel through traffic. When the car is stopped at a traffic light, the gas powered engine will cease to operate, and the electrical motor will take over in providing propulsion power for the car to move from the site. Once the car achieves a good level of speed, the gas powered engine in the hybrid car will automatically engage and cause the car to continue down the street under gas engine power. The heavy duty battery is continually charged by the electrical motor at the same time.

The energy savings are accumulated during the different stops and starts that the vehicle might experience as the automobile moves toward its destination. Whenever the gas powered engine is not engaged there is a cost savings realized in its lax state of operation. The hybrid motor is quite capable of consuming energy and generating the right amount of power at the same time. These moments of non-engagement will save the consumer money in gas cost every time the automobile is driven down the road.

In conclusion, there exist more logical advantages of owning a hybrid car which is an unstoppable growing trend and unconfrontational facts.

Toyota Avalon Review

The Toyota Avalon?s design was originally based upon the technology of the Toyota Camry. This four door, front wheel drive care became popular on the market, especially in 2006. The cabin of the Avalon is quite spacious and comfortable. They have added lavish high quality features including the leather trimmed seats with ergomanically designed controls. The perfectly tuned suspension and quiet engine complements the tranquil interior. It is currently vying in the market of all other full sized sedans and holding their own. In the past year, the Toyotal Avalon features all the latest technology in fuel efficiency, safety, and performance. The new models have the latest, but it is not extravagant in its styling. It is sleek and contemporary and gives the driver a more sophisticated look that one can not ignore.

It has been long said that a Toyota can be driven for over 100,000 miles and still keep on going and going. The Toyota Avalon is not exception to this rule. There has not been one Toyota Avalon out in the market that has been a flop. This is due to Toyota Corporation employing excellent marketing strategies and due to their high level of expertise when it comes to deciding what is right for the company. Toyota went from being Japan?s largest auto maker to America?s third largest and one of the best known manufactures in the world.

Part of Toyota?s quality is that if you are looking for replacement parts, you can go online now and search to find what you are looking for. Each certified Toyota Avalon part is designed to meet the exact requirements of the detailed Toyota user. Toyota parts are sure to give your vehicle a better quality ride, increased comfort and safety.

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.

Buick Skylark 1953

The Buick Skylark (first use of the name for a production vehicle) on one of three specialty convertibles produced in 1953 by General Motors; the other two were the Oldsmobile Fiesta and the Cadillac Eldorado. All three were limited production vehicles promoting General Motors' design leadership. Of the three, the Skylark had the most successful production run with 1,690 produced. This was considered quite an amazing sales feat, for the car had a list price in 1953 of slightly in excess of US$5,000. However, many languished in dealer showrooms and were sold at discount.

All 1,690 regular-production Skylarks built in 1953 (and all in 1954) were convertibles. The 1953s were based on the 2-door Roadmaster convertible, having identical dimensions (except height), almost identical convenience and appearance equipment, and a Roadmaster drive train. In 1953, the model designation for the Skylark was 76X, while the model designation for the Roadmaster convertible was 76R. The few options available to the Roadmaster convertible buyer were standard equipment to the Skylark buyer, albeit the base price for the well-equipped Roadmaster convertible was only about US$3,200.

The 1953 Skylark featured V8 power and a 12 volt electrical system, both a first for Buick, as well as full-cutout wheel openings, a styling cue that would make its way to the main 1954 Buick line. Also making its way into the 1954 Buick line was the cut-down door at the base of the side window line that bounced back up to trace around the rear window (or convertible top). This styling clue stayed with Buick for many years and can be found on any number of automobile brands to this day.

The 1953 Buick Skylark was a handmade car in many respects. The stampings for the hood, trunk lid and a portion of the convertible tub were the same as the 1953 Roadmaster convertible (and Super convertible, model 56R). The stampings for the front fenders, rear fenders, the outer doors, and a portion of the convertible tub were unique to the Skylark. All Skylark convertible tubs were finished with various amounts of lead filler. It is not unusual to find a substantial amount of lead filler just behind the doors near the bottom of the window line. The inner doors of the Skylark were made from the inner doors of the 2-door Roadmaster and Super by cutting the stamping in half approximately parallel with the ground and then welding the two pieces back together in a jig at an angle that produced the necessary door dip (see photos of finished car).

Although there were many unique design features of the 1953 Skylark, one that goes almost unnoticed today is that the top and seating of the car were lowered a few inches below the Roadmaster and Super convertibles. This was achieved not by changing the frame, body or suspension, but by cutting the windshield almost three inches shorter and lowering the side windows and convertible top frame. To accommodate people without bumping their heads with the top up, the seat frames and steering column were lowered.

The wheels of the 1953 Skylark were true wire wheels, produced by Kelsey-Hayes, with everything chromed save for the plated and painted "Skylark" center emblem. Although this was high style in 1953, the wheels were heavier than the regular steel wheels, would require periodic truing to keep them straight and balanced, and required tubes within the tires just when tubeless tires were becoming the norm, as they were throughout the rest of the Buick line.

For 1954, the Skylark returned, although radically restyled [1]. This Skylark featured elongated wheel cutouts, the interior of which were available painted a contrasting color to the body color. For example, black cars could receive white or red wheel wells. The trunk of the restyled Skylark was sloped into a semi-barrel shape. Tail lights were housed in large chromed fins that projected from the tops of the rear fenders.

The car was now based on the all-new shorter Century/Special chassis and not the top-of-the-line Roadmaster/Super chassis, also all-new for 1954. However, it did share the Roadmaster and Century powertrain, the highest output in the 1954 Buick model lineup. This powertrain was an evolutionary improvement, but very similar to the 1953 powertrain.

The model designation for the 1954 Buick Skylark was "100", a completely unique designation. The short wheelbase cars were the Buick Special: series 40, the Buick Century: series 60, and the Buick Skylark: series 100, albeit a series of just one model. All production Buick Skylarks were built as 2-door convertibles. They had the same luxury equipment as the 1953 Buick Skylarks.

Like their 1953 counterparts, the 1954 Skylark had a number of unique sheetmetal stampings, but without the hand labor that went into the 1953 Skylark production. In addition to unique front and rear fenders with the elongated wheel cutouts, the 1954 Skylark had a unique trunk with its semi-barrel shape and huge, rounded chrome fins. Interestingly, the hood was also unique to the 1954 Skylark in a small way. The hood ornament was quite different from all other Buick models for the 1954 model year. However, this same hood ornament, although unique in size to just this one model in 1954, was to portend the design of the 1955 Buick hood ornament used on all models of that year.

The cost of the Skylark, mixed with the public's dislike for the restyle and its perceived step down in rank to the Special/Century series versus the 1953 rank with the Super/Roadmaster series resulted in poor sales and the car's demise at the end of the 1954 model year.


Engines

* 322 in³ (5.3 L) Nailhead V8

GM Iron Duke engine

The Iron Duke (also called the 2500, 151, Pontiac 2.5, Cross Flow, and Tech IV, though the decal on the air filter assemblies actually reads "4 Tech") was a 2.5 L (151 in³) I4 piston engine. All Iron Dukes were built by Pontiac beginning in 1977 and ending in 1993.

This 151 was also used by American Motors (AMC) starting in 1980, as the base engine option in the RWD Spirit and Concord, and continuing in both cars through 1982. The AWD (4x4) Eagle carried the 151 as standard equipment for 1981, and carried it midway through the 1983 model year. It was also available (as the Hurricane) in economy model Jeep CJs. AMC replaced the Iron Duke 2.5L I4 with a 150cid Inline-4 of their own, derived from their evergreen sixes.

The Iron Duke is often confused with Chevrolet's Stovebolt-derived 153 from the 1960s Chevy II, but the engines are entirely different - the Iron Duke's intake manifold is on the passenger side, as opposed to the driver side. One thing that both share is the Chevrolet Small-Block bell housing bolt pattern.

Applications:

* 1977 Pontiac Astre
* 1978-1980 Pontiac Sunbird
* 1984-1988 Pontiac Fiero
* 1982-1985 Chevrolet Camaro
* 1985-1990 Chevrolet Astro
* 1985-1990 GMC Safari
* Chevrolet Celebrity
* Chevrolet S-10
* Chevrolet S-10 Blazer
* GMC Sonoma
* GMC S-15 Jimmy
* Chevrolet Monza
* Buick Skylark
* Buick Skyhawk
* Buick Century
* Pontiac 6000
* 1985-1991 Pontiac Grand Am
* Oldsmobile Ciera
* Oldsmobile Omega
* AMC Concord/Spirit (1980-82)
* Eagle (1981-83)
* Jeep CJ (1980-83)
* Grumman LLV United States Postal Service delivery vehicle

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.

Diesel Performance

If you were to modify a gas engine for performance, you would be required to install a different camshaft, bore out the cylinders to increase displacement, install high compression pistons and heads, increase fuel intake capability by installing a larger carburetor or injection system, adding a turbo charger or supercharger, adding a chip, and enlarging the exhaust system.

But then you are still restricted by emission control systems. On the other hand, diesel trucks and cars are mostly turbo charged, and they already run at a higher compression ratio. Whereas on the gas vehicles you would have to make those changes. If you were to make those changes to a gas engine you would truly have a ground pounding beast, but would lose every day drive ability.

The Diesels on the other hand are nice to drive around even with considerable modification. With a cold air intake, a chip, more efficient injectors, and a more open exhaust system, the diesels are still a nice ride, but when you really give it the gas, all heck breaks loose. There is enormous power without reducing drive ability.

Because of the nature of diesel engines they are designed from the factory to withstand much higher compression ratios than a gas engine. The diesel fuel combusts when it is compressed to a certain point whether or not there is optimum air. By simply shooting more fuel into the combustion chamber you can make more power. When you then improve the air ratio & timing of the fuel - you can make dramatic power and also improve engine efficiency. Gasoline
requires a spark to ignite it & must have the appropriate mixture of air to burn properly. There is also a lot more energy in a given amount of diesel fuel than in an equal amount of gasoline.

I will now break down the most popular modifications and explain their benefits.

1. A cold air intake is sealed away from the hot engine air, and is
located where it can take in more air. Cold air intakes are equipped with a filter that can take in up to 300% more air. Cold air takes up less space. So there can be more air, more air helps to burn all the fuel, thus giving more power and better fuel economy.

2. Chips make alterations to how the fuel is delivered to the engine, making it more efficient and more powerful.

3. A bigger exhaust or a mandrel bent exhaust (keeps the tube round, and the size constant) improves exhaust flow. Getting exhaust away from the engine is just as important in combustion as getting air into the engine. There are exhausts now that will even vacuum exhaust away from the engine, making it so that the engine doesn’t have to do that work.

All of these modifications add to the fuel economy of the diesel engine, and will over time actually pay for themselves in gas savings, and will continue for years after they are paid for to keep your money in your pocket. Diesels are the wave of the future and more and more economy vehicles are being produced in diesel versions because they are capable of so much better economy.

Detonation, Knock, and Pre-Ignition 101

As you probably have already figured out, detonation (aka "knock") is a big issue in the world of forced induction. You probably know that detonation is a bad thing, and that by adding a supercharger (or any forced induction power adder), you must take additional measures to avoid detonation, especially if your engine has other modifications. Normally the simple solution to stop detonation is to run higher octane fuel... but before we get ahead of ourselves, let's start from the beginning.

What is detonation / knock?

Under normal conditions, the combusting air and fuel mixture inside the combustion chamber ignites in a controlled manner. The mixture is ignited by the spark, normally in the center of the cylinder, and a flame front moves from the spark towards the outside of the cylinder in a contolled burn. Detonation occurs when air and fuel that is ahead of the flame front ignites before the flame front arrives because it becomes overheated. Under these conditions, the combustion becomes uncontrolled and sporadic and often produces a pinging noise, or a "knock" noise when the conditions become worse.

So far, detonation sounds cool... why is it bad?

Detonation is definitely not cool. Detonation causes sudden pressure changes in the cylinder, and extreme temperature spikes that can be very damaging on engine pistons, rings, rods, gaskets, bearings, and even the cylinder heads. Even the best engine components cannot withstand severe detonation for more than a few seconds at a time. More severe detonation obviously leads to more severe forms of engine damage. If there is enough heat and pressure in the combustion chamber, detonation can begin to occur before the spark plug even fires, which would normally initiate the combustion. Under these circumstances, known as "pre-ignition", the piston may be travelling up towards a wave of compressed, exploding gas. These are the worst kinds of detonation conditions, and can bend con-rods and destroy pistons.

What causes detonation?

Detonation occurs when several conditions / factors inside the combustion chamber exist at the same time. Increased compression, high temperatures, lean fuel/air mixture, advanced ignition timing, and lower octane fuels are all factors that PROMOTE detonation conditions. The good news is that, because there are so many factors in play, you can always find a way to eliminate detonation if it exists.

So, where do superchargers fit in?

A supercharger increases the amount of air inside the combustion chamber, which in turn increases the compression inside the combustion chamber. Along with increased compression comes higher temperatures and higher pressures, which as we know, tend to increase the chances that some form of detonation will occur. In order to compensate for the increased compression and heat, we must change one or more of the other factors / conditions to move us away from our detonation threshhold. Tuning the supercharger system to the engine in this way for maximum performance without detonation is something that supercharger manufactuers do so, chances are, you won't have to worry about it unless you do other modifications to your engine that place you closer to your detonation threshhold.

How do I get rid of it?

The two most common tricks used by supercharger manufactuers and engine tuners looking to obtain maximum performance without detonation is 1. use higher octane fuel, and 2. retard the ignition timing.

Higher octane fuel burns more controllably and is not as likely to combust before the flame front. This is why racing engines use 100+ octane gasoline. The ONLY benefit of racing gasoline is that it moves you away from the detonation threshhold, which allows you to be more aggressive with power producing factors - i.e. raise compression, advance timing, etc. This is why you'll be disappointed if you put racing gasoline in your mom's bone-stock '82 Toyota Cressida thinking you'll turn it into a race car. If you don't have detonation, the increased octane will do you no good. For cars designed for daily street driving, you obviously won't want to fill up with 100+ octane fuel every week at the tune of 5 bucks a gallon. This is why supercharger manufactuers tune their supercharger systems to run properly without detonation on 91 octane fuel - aka "premium" at your local gas station (in some states premium gasoline is around 93 octane).

Retarding the ignition timing will delay the timing of the spark, which also moves you away from your detonation threshhold. Most popular "power programmers" or "chips" increase engine power by advancing the ignition timing, and requiring you to run a higher octane fuel to avoid detonation. These work great, except the advanced ignition timing is NOT compatible with most superchargers, unless you're happy to run 100 octane fuel. In fact, many supercharger systems include an "ignition boost retard" that retards the ignition timing when it senses boost from the supercharger. This allows you to maintain stock performance while not under boost, yet still remain safe while the supercharger is making its boost (and power).

Another way to avoid detonation is to cool the incoming air charge to lower the temperature inside the combustion chamber. On a supercharged application, this task can be handled by an intercooler or by a water injection system (less common). The intercooler takes the incoming air charge and passes it over a series of air-cooled or water-cooled fins and ducts, thus cooling the air in the same way that a radiator cools your engine's coolant. Intercoolers are thus very popular in higher output supercharger systems, where detonation becomes more of a problem. Often times, the intercooler allows you to run more boost and also allows you to eliminate the ignition boost retard, meaning you'll notice increased performance, and still experience no detonation. Another way to lower the temperature of the combusting air and fuel is to run cooler heat range spark plugs. Many supercharger manufacturers will recommend cooler plugs for you supercharged engine.

Because lean condition (fuel starvation) also contributes to detonation, it is important to make sure that the fuel system (pump, injectors, etc.) is capable of delivering the increased fuel requirements of the supercharged engine. Often times, an otherwise perfectly tuned engine will experience detonation just because the fuel pump can't deliver enough fuel to the engine. Upgrading certain fuel components is almost always necessary when supercharging an engine. Most supercharger systems normally include the upgraded fuel components if they are necessary. If you are installing a supercharger on an engine with other modifications, make sure you consider the additional fuel requirements and compensate with larger injectors and / or a bigger fuel pump.

Some modern vehicles come with "knock sensors" that listen for detonation, and automatically retard the ignition timing to eliminate detonation. Although these devices are effective in preventing engine damage, they are not tuned for performance, so you should not rely on the knock sensors and expect your engine to run its best.

Conclusion

Altough detonation can be potentially damaging to an engine, a simple understanding of what it is, and what causes it, will help you stay away from your detonation threshhold. Pay attention to "knock" and pinging noises that come from your engine becuase they could indicate detonation inside the combustion chamber and should be dealt with immediately. If you're looking for a new supercharger system, don't worry too much about detonation - the manufacturers have designed the system for use on your stock engine, and if you follow the manufactuer's fuel recommendations, you will not have a detonation problem. If you ever do notice detonation, perhaps from bad (low octane) gasoline or extremely high air temperatures, just drive with a light foot until you are able to resolve the cause of the problem.

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.

Stratified charge engine

The stratified charge engine is a type of internal-combustion engine, similar in some ways to the Diesel cycle, but running on normal gasoline. The name refers to the layering of fuel/air mixture, the charge inside the cylinder.

In a traditional Otto cycle engine the fuel and air are mixed outside the cylinder and are drawn into it during the intake stroke. The air/fuel ratio is kept very close to stoichiometric, which is defined as the exact amount of air necessary for a complete combustion of the fuel. This mixture is easily ignited and burns smoothly.

The problem with this design is that after the combustion process is complete, the resulting exhaust stream contains a considerable amount of free single atoms of oxygen and nitrogen, the result of the heat of combustion splitting the O2 and N2 molecules in the air. These will readily react with each other to create NOx, a pollutant. A catalytic converter in the exhaust system re-combines the NOx back into O2 and N2 in modern vehicles.

A Diesel engine, on the other hand, injects the fuel into the cylinder directly. This has the advantage of avoiding premature spontaneous combustion—a problem known as detonation or ping that plagues Otto cycle engines—and allows the Diesel to run at much higher compression ratios. This leads to a more fuel-efficient engine. That is why they are commonly found in applications where they are being run for long periods of time, such as in trucks.

However the Diesel engine has problems as well. The fuel is sprayed right into the highly compressed air and has little time to mix properly. This leads to portions of the charge remaining almost entirely air and others almost entirely of unburnt fuel lacking for oxygen. This incomplete combustion leads to the presence of other pollutants such as polycyclic aromatic hydrocarbons and the plainly visible exhaust soot.

The stratified charge design attempts to fix the problems with both fuels. It uses a direct-injection system, like the Diesel, with its inherent ability to be run at efficient high compressions. However, like the Otto, it relies on gasoline's ability to mix quickly and cleanly in order to avoid the poor combustion found in the Diesel.

To do this the fuel injectors are aimed to inject the fuel into only one area of the cylinder, often a small "subcylinder" at the top, or periphery, of the main cylinder. This provides a rich charge in that area that ignites easily and burns quickly and smoothly. As the combustion process proceedes it moves to a very lean area (often only air) where the flame-front cools rapidly and the harmful NOx has little opportunity to form. The additional oxygen in the lean charge also combines with any CO to form CO2, which is less harmful.

The much cleaner combustion allows for the elimination of the catalytic converter and allows the engine to be run at leaner mixtures, using less fuel.

After years of trying, this layout has proven not to be terribly easy to arrange. The system has been used for many years in slow-running industrial applications, but has generally failed to develop into an automobile engine. Many attempts have been made over the years, notably in Wankel engine applications, but only the Japanese car manufacturers have pressed ahead with piston-engine development. It is estimated that they have spent several hundreds of millions of dollars in R&D since the 1970s.

Honda's CVCC engine, released in the early 1970s models of Civic, then Accord and City later in the decade, is a form of stratified charge engine that had wide market acceptance for considerable time. The CVCC system had conventional inlet and exhaust valves and a third, supplementary, inlet valve that charged an area around the spark plug. The spark plug and CVCC inlet was isolated from the main cylinder by a perforated metal plate. At ignition a series of flame fronts shot into the very lean main charge, through the perforations, ensuring complete ignition. In the Honda City Turbo such engines produced a high power-to-weight ratio at engine speeds of 7,000 rpm and above.

Today, however, several stratified charge engines are appearing on the market. Mazda and Mitsubishi both have cars using these designs, Volvo Cars recently teamed with Mitsubishi to produce their designs in Europe, Audi has a car using the design and PSA Peugeot Citroën has developed such an engine. The primary "sales advantage" of these engines is fuel economy. They run at a leaner setting and use, about, 15 to 20% less fuel than non-stratified designs.

Saving fuel cost the easy way

With rising gas prices and environmental issues taking center stage, it’s no wonder that many people are looking into more fuel efficient cars. But what if you can’t afford a new hybrid, or you need the extra room that your SUV gives you? The good news is there are many ways to make whatever car you own more fuel-efficient, saving you gas money and helping to reduce emissions at the same time.

Try reduce vehicle weight, do an inspection and remove anything that doesn't do any importants to the car, don't want the car to be a drag. The ligther the car the less fuel it needs to get moving.

Check tyre pressure, make sure its not to soft or to hard(check car manual for tyre pressure)

Keeping your car running well and servicing it when needed will also help keep your vehicle running smoothly and efficiently. A car that has to work harder because of parts that need to be cleaned or replaced will hurt your fuel economy. Parts to check often are: air filters, spark plugs, PVC valve, fuel injector, oxygen sensor and fuel filter. These are some of the most common parts that can affect your car’s fuel efficiency, especially if you have a high performance vehicle or SUV.

Making an effort to take care of your vehicle and utilizing these easy steps will not only help save you money at the gas pump, you will be helping the environment as well. Now that you know how easy it is you can get started today!

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.

BMW N52 engine

The BMW N52 is the BMW's latest straight-6 engine, which debuted in 2004 on the BMW E63 630Ci. Its crankcase is made entirely of magnesium-aluminum, a first in the world of engine construction. It is the lightest production engine of its size class in the world, at 161kg/354lbs.

It includes BMW's second generation Valvetronic system and Double-VANOS for fuel-efficiency (12% fuel savings over the previous generation BMW M54 engine - and increases performance. Producing 63kW (85.5hp) per liter of displacement, it has the lowest weight per horsepower of any six cylinder engine (1.24hp per kilogram with the latest version). It is the world’s lightest six-cylinder engine.

It was awarded as one of Ward's 10 Best Engines of the Year in 2006 and 2007. Technologically it is even more advanced than the new N54B30 bi-turbo, which is based on an older M54B30 design and lacks several improvements that BMW has made for this engine.

All BMWs are available with this engine in at least one version - the only exception being the X5 which still uses the predecessor, M54B30 as its 3.0 Liter gasoline engine option.

The N52 is BMW's 12th generation production straight-6 engine.


Models

Engine
N52B25

Displacement
2.5 L (2497 ccm/152 in³)

Power
130 kW (174 hp) @ 5800
160 kW (215 hp) @ 6500

Torque
230 N·m (170 ft·lbf) @ 3500-5000
250 N·m (184 ft·lbf) @ 2750-425

Redline
7000rpm

Year
2005



Engine
N52B30

Displacement
3.0 L (2996 ccm/182 in³)

Power
190 kW (255 hp) @ 6600
195 kW (265 hp) @ 6600
200 kW (272 hp) @ 6650

Torque
300 N·m (221 ft·lbf) @ 2500-4000
315 N·m (232 ft·lbf) @ 2750-4250
315 N·m (232 ft·lbf) @ 2750-4250

Redline
7000rpm

Year
2004
2005
2006



N52B25

The N52B25 comes in two versions, both displacing 2.5 L (2497 ccm/152 in³). The first produces 130 kW (174 hp) at 5800 rpm and 230 N·m (170 ft·lbf) at 3500-5000 rpm while the more powerful version is rated at 160 kW (215 hp) at 6500 rpm and 250 N·m (184 ft·lbf) at 2750-4250 rpm.

Applications:

* 130 kW (174 hp) and 230 N·m (170 ft·lbf)
o E60/E61 523i (Not in the US market) Sedan and Touring
o E90 323i (US market only) Sedan
* 160 kW (215 hp) and 250 N·m (184 ft·lbf)
o E60/E61 525i/525xi Sedan and Touring
o E90/E91/E92/E93 325i/325xi Sedan, Touring, Coupè and Convertible
o E83 X3 2.5si (Not in the US market) Sports Activity Vehicle
o E85 Z4 2.5si (Not in the US market) Roadster


N52B30

The N52B30 comes in three versions, all displacing 3.0 L (2996 ccm/182 in³) and produces variable outputs depending on the BMW model that it comes with (with changes to the variable resonance system-omitted, dual plenum runner system-also omitted and variable back pressure muffler-omitted) 190 kW (255 hp) at 6600 and 300 N·m (221 ft·lbf) at 2500-4000 rpm is the first and most produced version, while the second one is more powerful at 195 kW (265 hp) at 6600 and 315 N·m (232 ft·lbf) at 2750-4250 rpm. The third version is just starting to replace the first 190kW versions on the E90/E60 in Late 2006 and has first been released on the new E92 330i Coupè. It will produce 200 kW (272 hp) at 6650 and 315 N·m (232 ft·lbf) at 2750-4250 rpm.

Applications:

* 190 kW (255 hp) and 300 N·m (221 ft·lbf)
o E60/E61 530i/530xi Sedan and Touring (*)
o E63/E64 630i (Not in the US market) Luxury Coupè and Convertible
o E65/E66 730i/730Li (Not in the US market) Luxury Sedan
o E90/E91 325i, 328i, 330i Sedan, Touring (*)

The models marked with a star (*) will soon receive the 200kW version upgrade - sometime in late 2006.

* 195 kW (265 hp) and 315 N·m (232 ft·lbf)
o E85/E86 Z4 3.0i and 3.0si Roadster and Coupè
o E87 130i (Not in the US market) Hatchback
* 200 kW (272 hp) and 315 N·m (232 ft·lbf)
o E92/E93 328i/328xi Coupè, 4WD Coupè and the upcoming Hardtop Convertible
o E83 X3 3.0si Sports Activity Vehicle

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.”

Crower six stroke engine

The Crower six-stroke engine is a concept under development by Bruce Crower, known for the invention and manufacture of many devices now used in automotive acceleration racing (see National Hot Rod Association and drag racing).

Two extra strokes are added to the customary internal combustion engine four stroke Otto cycle. A fifth down-stroke is a "steam stroke" and the sixth is to exhaust the expanded steam while venting heat from the engine.

The engine cold starts on the Otto cycle, coasting through the fifth and sixth strokes for a short period. After the combustion chamber temperature reaches approximately 400 degrees Fahrenheit ( 200oC ), a mechanical operation phases in the fifth and sixth cycles. Just prior to the fifth-cycle, water is injected directly into the heated combustion chamber via the converted diesel engines fuel injector pump, creating steam and another power stroke. The phase change from liquid to steam removes the excess heat of the combustion stroke forcing the piston down (a second power stroke). As a substantial portion of engine heat now leaves the cylinder in the form of steam, no cooling system radiator is required. Energy that is dissipated in conventional arrangements by the radiation cooling system has been converted into additional power strokes.


Positive aspects:

Crower claims a 40% reduction in fuel consumption and reduced exhaust emissions.

The base engine for modification uses a high compression ratio which is essential for compression ignition. This high ratio is useful in extracting the full potential of ethanol (one of many fuels that this engine may use). These high ratios are a dramatic alteration over present multi-fuel engines which typically use a 10:1 compression ratio, similar to gasoline engines.

The cooler piston top and reduced combustion chamber temperature (heat is extracted in the conversion of injected water to steam) may allow gasoline to be used at very high compression ratios or without environmentally harmful anti-knock chemicals, which are now in universal use with conventional automobile gasoline engine applications. Under these circumstances, far more energy from the gasoline fuel could be converted to horsepower output. (Very high compression ratios are used in racing engines as a means to increase power.)

The weight of most conventional cooling system parts can be eliminated.

The power loss to operate fans and pumps is eliminated.

The mechanical modifications needed to "six-stroke" a small air-cooled industrial diesel already being manufactured are far less complicated than any hybrid system. Many maintenance features of this engine would be parallel or identical to the knowledge base of mechanics well-versed with gasoline, diesel, and racing engines.

The modification to water injection could be done simultaneous to the use of all liquid and gaseous fuels now in widespread use (diesel, gasoline, ethanol, methanol, LP gas, natural gas as well as all plant-derived oils) in the conventional four-stroke portion of the engine.

Physical engine size reduction is possible as one-third of the engine strokes produce power (in the Crower six-stroke), instead of one-quarter (in the Otto cycle).

The higher percentage of power strokes may allow lower operational speeds, with higher torque output at lower and broader rpm ranges. Lower operational speed might allow designs with greater crankshaft diameter, for the use of engine dimensions with inherently more torque potential.

This system is ideal for heavy industrial applications and electric utility peaking plants where "dirty" internal combustion plants are commonly used for stand-by generation.

This is the only "steam engine" that does not require a certified pressure boiler and related hardware complexities, dangers, and weight penalties.


Obstacles or problems:

A warm up period of at least several minutes would be required in all automotive applications. Power is reduced during the warm-up period.

A steam-free cool down period is required to clear water/steam from the engine.

Cold climate anti-freezing electrical resistance heating systems would be required in the mobile water supply.

Water is more dense than all motor fuels.

Oil adulteration, from the water/steam cycle, is an obstacle to be dealt with, though additional piston/cylinder sealing rings can be added easily.

The weight of an oil separator and a water condenser are likely additions.

Current anti-air pollution legislation does not allow for experimental use status on public roadways.

Tips on saving fuel

In todays high oil prices, one must learn to use it more wisely. heres some tips on how:

* Take advantage of rolling resistance rather than heavy braking to help slow you down. This deceleration technique is one of the best for fuel saving.

* Avoid unnecessary braking.

* Maintain a steady speed.

* Drive in gear corresponding to the speed.

* A poorly tuned engine can increase fuel consumption by up to 50%

* Driving at 90 kilometers an hour rather than 100 can reduce fuel consumption by 10%

* Under inflated tires can increase fuel consumption by 5%

* A loaded roof rack will increase fuel consumption by as much as 5% in highway driving.

* Even an empty roof rack can increase consumption by 1%. If the carrier is not attached to the vehicle, remove it when not in use.

* Avoid "Jack Rabbit" starts, not only do they increase fuel consumption, but are hard on your tires. Anticipating stops and avoiding abrupt stops will decrease fuel consumption and increase the life of your brakes and tires.

* Avoid unnecessary steering wheel movement since each sideward movement of the tire causes fuel-consuming drag.

* Accelerate slowly on gravel or slippery roads.

* Reviving the engine just before turning off the ignition costs extra fuel and may cause engine damage.

* Avoid using the air conditioner at lower speeds.

* Changing spark plugs regularly can save a lot.

* neutral the gear at red light stops.

* Do not use the clutch too much.

* Get your vehicle serviced regularly.

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.

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).

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.

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.

Napier Nomad engine (aircraft engine)

The Nomad was a complex Diesel cycle aircraft engine from Napier & Son of the UK. The Nomad used a turbine to recover power from the exhaust of the otherwise conventional Diesel engine, resulting in a specific fuel consumption that remains unmatched by an aircraft engine 50 years later.


History

In 1945 the Air Ministry asked for proposals for a new 6,000 horsepower (4,500 kW) class engine with good economy. Curtiss-Wright was designing an engine of this sort of power known as the "turbo-compound", but Sir Harry Ricardo, one of Britain's great engine designers, suggested that the most economical combination would be a similar design using a diesel two-stroke in place of the Curtiss's petrol engine.

Prior to World War II Napier had licensed the Junkers Jumo 204 diesel design to set up production in the UK as the Napier Culverin, however the start of the war made the Sabre all-important and work on the Culverin was stopped. In response to the Air Ministry requirements they dusted off this work, combining two enlarged Culverins into an H-block similar to the Sabre, resulting in a massive 75 litre design. Markets for an engine of this size seem limited however, and instead they returned to the original Culverin-like horizontally opposed 12 cylinder design, resulting in the Nomad.

Design

The Nomad design was incredibly complex, essentially two engines in one. One was a supercharged Diesel similar to the Culverin. Below this was a complete turboprop engine, based on their Naiad design. The output of the turboprop was geared to a shaft running inside the Diesel's, driving the front propeller of a contra-rotating pair. As if that were not enough, during takeoff additional fuel was dumped into the rear turbine stage for additional power, and turned off once the plane was cruising.

The compressor and turbine assemblies of the Nomad 1 were tested during 1948, and the complete unit was run in October 1949. The prototype was installed in the nose of an Avro Lincoln bomber for testing, and first flew in 1950. In total the Nomad 1 ran for just over 1,000 hours, and proved to be rather temperamental, but when running properly it could produce 3000 hp (2,200 kW) and 320 lbf (1.4 kN) thrust. It had a specific fuel consumption (sfc) of 0.36 lb/(hp·h) (0.22 kg/(kW·h)).

Even before the Nomad 1 was running, its replacement, the Nomad 2, had already been designed. In this version an extra compressor stage was added, replacing the original supercharger. This stage was driven by an additional stage in the turbine, so the system was now more like a turbocharger and the compressed air for the Diesel was no longer "robbing" power. In addition the propeller shaft from the turbine was eliminated, and geared using a hydraulic clutch into the main shaft. The result was smaller and considerably simpler, a single engine driving a single propeller.

While the Nomad 2 was undergoing testing, a prototype Avro Shackleton was lent to Napier as a testbed. The engine proved bulky, like the Nomad 1 before it, and in the meantime several dummy engines were used on the Shackleton for various tests. By 1954 interest in the Nomad was dropping, and after the only other project based on it was cancelled, work on the engine was ended in April 1955.


Specifications (Nomad 2)

General characteristics

* Type: Twelve-cylinder liquid-cooled horizontally opposed Diesel combined with a turboprop aircraft engine
* Bore: 6 in (152 mm)
* Stroke: 7.375 in (187 mm)
* Displacement: 2,502 in³ (41 L)
* Dry weight: 3,580 lb (1,624 kg)

Components

* Cooling system: Liquid-cooled

Performance

* Power output: 3,135 ehp (2,338 kW) max take-off at 89 psia (614 kPa) including thrust power from the turbine
* Specific power: 1.25 ehp/in³ (57.0 kW/L)
* Compression ratio:
o Engine 8:1
o Turboprop compressor 8.25:1
* Specific fuel consumption: 0.345 lb/(ehp·h) (0.210 kg/(kW·h))
* Power-to-weight ratio: 0.88 ehp/lb (1.44 kW/kg)

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.

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.

Cleaning a car engine

start the engine, let it warm up for a few minutes then shut it off, in order to soften up collected grease and grit in your engine compartment.

correct cleaning temperature for the engine to be is warm but not hot- you should be able to hold your hand to the engine without burning it.

Before cleaning the engine with water, it's imperative to cover electrical and mechanical components beneath the hood to protect them from water damage.

The air intake/air filter, the distributor, the coil and the oil dipstick/breather should be covered using plastic baggies sealed with rubber bands.

It's a good idea to also check the tightness of the
1) oil filler cap
2) power steering filler cap
3) windshield washer fluid cap
4) oil dip stick
5) battery filler caps


Spray all over the engine and engine compartment with non-petroleum based degreaser,

starting from
the bottom and working up.

Citrus degreasing products will not harm the paint or finish on aluminum components and are biodegradable.

After 3-5 minutes use a soft cotton towel or brush to carefully scrub the heavy dirt. Re-spray and re-scrub any areas that need additional cleaning.

Once the whole engine and engine compartment has been cleaned, rinse thoroughly with water.

Try to avoid getting the degreaser on any exterior painted areas as it will strip the wax from your finish. If this happens, it's okay, but you'll have to give those areas a good wax job when you're through.

Once clean, right away take off all the plastic baggies.

Dry any collected water, especially on aluminum parts, with a soft cotton towel.

Using paper towels, dry the battery.

Start the engine and let it warm up, in order to dry the remainder of the engine and evaporate any moisture in sensitive components. Once everything is dry and cooled off is a good chance to put a coating of rubber protectant on your rubber hoses, plastic shields and rubber gaskets.

If the battery terminals are dirty, disconnect the cables and clean both the cable terminals and battery posts with a wire brush.

Reconnect the terminals and retighten. Get some battery terminal spray and spray on the connected terminals to protect them from corrosion.

A thin coating of non-silicone lubricant should be applied to any hinges, throttle cables, cruise control cables and similar moving parts. Now check and top off fluid levels.

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.

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.

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)

Ferox (fuel additive)

Ferox is a fuel additive. It was developed by Wesley Parish in 1985 from work done on experimental burn rate modifiers for solid rocket propellant systems used in the aerospace industry. Ferox was originally designed to lengthen the life engines. Until recently, it has been used predominantly in the marine, mining, and trucking industries. It is now used as a fuel additive in common automobile engines using gasoline, diesel, and others. The newest form is in a small tablet that is added with fuel into the tank to be dissolved.

There is evidence that ferox can lower polluting emissions, improve gas mileage, and reduce deposit build-up. There are also claims of prolonging engine life. However, the extent of these benefits for average fuel consumers is still not clear.

The product has been registered with the Environmental Protection Agency.

Ferox works as a catalyst, which lowers the activation energy of the rate determining step to break down build-up within the engine. This allows the carbon deposits to burn off at much lower temperatures.

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).

Saab Variable Compression engine

The Saab Variable Compression engine was a development project of Saab Automobile, for which it won an award both in 2000 and 2001.

In a normal internal combustion engine, because cylinder bore diameter, piston stroke length and combustion chamber volume are almost always constant, the compression ratio (CR) for a given engine is almost always constant, until engine wear takes its toll.

One exception is the experimental Saab Variable Compression (SVC) engine, designed for the Saab 9-5. This engine uses a technique that dynamically alters the volume of the combustion chamber, thus changing the compression ratio.

To alter the combustion chamber volume, the SVC 'lowers' the cylinder head closer to the crankshaft. It does this by replacing the typical one-part engine block with a two-part block, with the crankshaft in the lower block and the cylinders in the upper portion. The two blocks are hinged together at one side. By pivoting the upper block around the hinge point, the volume of the combustion chamber can be modified. In practice, the SVC adjusts the upper block through a small range of motion, using a hydraulic actuator.

The SVC project was shelved by General Motors, when it took over Saab Automobile, due to cost.

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.

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.

Alcohol fuel

Rising energy prices and global warming have led to increased interest in alternative fuels. Alcohol has been used as a fuel in other points in history but fossil fuels have become the dominant energy resource for the modern world. Generally speaking, the chemical formula for alcohol fuel is CnH2n+2O. The larger n is, the higher the energy density.

The first four aliphatic alcohols (methanol, ethanol, propanol, and butanol) are of interest as fuels because they can be synthesized biologically, and they have characteristics which allow them to be used in current engines. One advantage shared by all four alcohols is octane rating. Biobutanol has the advantage that its energy density is closer to gasoline than the other alcohols (while still retaining over 25% higher octane rating).

Alcohol fuels are usually of biological rather than petroleum sources. When obtained from biological sources, they are sometimes known as bioalcohols (e.g. bioethanol). It is important to note that there is no chemical difference between biologically produced alcohols and those obtained from other sources. However, ethanol that is derived from petroleum should not be considered safe for consumption as this alcohol contains about 5% methanol and may cause blindness or death. This mixture may also not be purified by simple distillation, as it forms an azeotropic mixture.

Bioalcohols are still in developmental and research stages. Use of optimized crops with higher yields of energy, elimination of pesticides and fertilizers based on petroleum, and a more rigorous accounting process will help improve the feasibility of bioalcohols as fuels.

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).

Pushrod engine

A pushrod engine or I-head engine is a type of piston engine that places the camshaft in the cylinder block (usually beside and slightly above the crankshaft in a straight engine or directly above the crankshaft in the V of a V engine) and uses pushrods or rods to actuate rocker arms above the cylinder head to actuate the valves. Lifters or tappets reside in the engine block between the camshaft and pushrods.

This contrasts with an overhead cam (OHC) design which places the camshafts above the cylinder head and drives the valves directly or through short rocker arms. In an OHC engine, the camshafts are normally part of the cylinder head assembly, while in an I-head engine the camshaft (rarely more than one) is part of the main engine block assembly.

Pushrod engines are perceived to be "old fashioned" by the modern automotive press, the cause is historical: While both layouts are over 100 years old, the I-head engine came first. OHC engines were developed as more expensive high-performance engines and have largely replaced the pushrod design in countries where cars are taxed based on engine displacement. In 1949, Oldsmobile introduced the Rocket V8. It was the first high-compression I-head design, and is the archetype for most modern pushrod engines. General Motors is the world's largest pushrod engine producer with engines such as the 3800 Series III Supercharged V6 (260 hp, 280 lb/ft torque), LS7 Chevrolet Corvette 7.0L V8 Engine (505 hp, 475 lb/ft torque) and LS4 5.3L DOD V8 (303 hp, 323 ft·lbf torque). Fewer pushrod type engines remain in production, a result of the fact that it has become difficult to achieve competitive engine performance with the configuration. However, in 2002, Chrysler introduced a new pushrod engine: a 5.7L Hemi engine. The new Chrysler Hemi engine presents advanced features such as variable displacement technology and has been a popular option with buyers. The Hemi was on the Ward's 10 Best Engines list for 2003 through 2007.



Limitations

Three specific problems remain with pushrod engines:

* Limited engine speeds or rpm - Pushrod engines have more reciprocating mass, suffer more easily from valve "float", and exhibit a tendency for the pushrods themselves to flex or snap at high engine speeds. Therefore a pushrod engine cannot revolve ("rev") at engine speeds as high as an OHC design. Modern pushrod engines generally rev to 6,000 rpm: compare this to modern OHC engines that can easily rev from 7,000 rpm in average engines to near 20,000 rpm in Formula One racing engines. High-rev pushrod engines have also been developed — in 1969, Chevrolet offered a Camaro Z28 with a pushrod V8 that could rev to 8,000 rpm and the Volvo B18 and B20 engines can rev to more than 7,000 rpm. Various pushrod racing engines are capable of reaching from 9,000 in some series to 10,500 rpm in others.

Because overall power is computed by multiplying torque by revolution speed (HP = (RPM x LB-FT) / 5252), an engine capable of revving higher will produce more power from the same amount of torque than one revving lower. A pushrod engine therefore needs to have a larger displacement to match the power output of an OHC engine. A good comparison would be the 3.9L GM 3900 Engine to the 3.0L Honda J-series V6. The smaller (in displacement) Honda Engine produces more power, while requiring less torque to do so.

* Difficulty in using crossflow cylinder heads in straight engine configurations - A few straight pushrod engines have been manufactured with crossflow heads, such as the six cylinder Humber Super Snipe. These engines combined much of the performance of the overhead camshaft with the ease of service of the pushrod, but were more expensive to manufacture than either competing design.

* Limited design flexibility - The biggest benefit of an OHC design is the use of multiple intake and exhaust valves and variable valve timing. Most modern pushrod engines have two valves per cylinder, while many OHC engines use three, four or even five valves per cylinder to achieve greater efficiency and power. Recently, however, GM has begun offering a pushrod V6 with VVT, and Cummins' ISB is a 4-valve pushrod straight-6. For the 2006 model year, General Motors will introduce the Vortec 6200. This is the first mass-produced pushrod engine to feature variable valve timing. The system adjusts both intake and exhaust timing between two settings. There is even a company called Arao Engineering that has developed and patented a 32-valve aluminum cylinder head for various pushrod engines like the small/big block Chevrolet engines and Ford small/big block engines.


Advantages

In contrast, pushrod engines have two specific advantages:

* Smaller overall packaging - Because of the camshaft's location inside the engine block, pushrods are generally more compact than an overhead cam engine of comparable displacement. For example, Ford's 4.6 L OHC modular V8 is larger than the 5.0 L I-head Windsor V8 it replaced and GM's 4.6 L OHC Northstar V8 is slightly taller and wider than GM's larger displacement 5.7 to 7.0 L I-head LS V8. The Ford Ka uses the venerable Kent Crossflow pushrod engine to fit under its low bonnet line.

* Less complex drive system - Pushrod engines have a less complex drive system when compared with OHC engines. Most OHC engines drive the camshaft or camshafts using a timing belt, a chain or multiple chains. These systems require the use of tensioners which add some complexity to the engine.


1994 Mercedes Indianapolis 500 engine

The Indy 500 race in Indianapolis each year bears some vestige of its original purpose as a proving ground for automobile manufacturers, in that it once gave an advantage in engine displacement to engines based on stock production engines, as distinct from out-and-out racing engines designed from scratch. One factor in identifying production from racing engines was the use of pushrods, rather than the overhead cams used on most modern racing engines; Mercedes-Benz realized before the 1994 race that they could very carefully tailor a purpose-built racing engine using pushrods to meet the requirements of the Indy rules and take advantage of the 'production based' loophole but still design it to be state of the racing art in all other ways, without any of the drawbacks of a real production-based engine. They entered this engine in 1994, and, as expected, dominated the race. After the race, the rules were changed in order to reduce the amount of boost pressure allowed to be supplied by the turbocharger. The inability of the engine to produce competitive power output after this change caused it to become obsolete after just the one race, as Mercedes-Benz knew it would when deciding a victory at Indy was worth it.

The 4A-FE DOHC engine

The 4A-FE DOHC engine is very simple, reliable, durable and economical. This engine will never give you a problem if you maintain it well.
1.8L 16 valve model 1ZZ-FE . It has lightweight aluminium block and aluminium head.
Tuned intake manifold allows the engine to perform more evenly.
No more timing belt - using the chain instead allows to reduce maintenance cost. Models after 2001 come with variable timing for better efficiency.
This engine also appears to be very reliable. It has impressive power (120 h.p) and really low fuel consumption. The engine runs very smooth at any speed range, I'd only mention that it's a little more noisy than previous model.

Checking the automatic transmission fluid

Place your car at a level surface and engage the parking brake. Start the engine. Set transmission shifter in "P" (Park) position, and let the engine idle (on some cars this procedure may be different, check the owners' manual for details). Pull the transmission dipstick. Check your owners manual to find where transmission dipstick is located in your car.

Wipe it off with a clean lint free rag. Then insert it back carefully all the way down into its place.

Pull again and check the fluid level. If the engine is cold, it should be within "COLD" marks. If the car was driven and is fully warmed up, the level should be at the upper end of the "HOT" mark. If it's just a little bit lower I wouldn't worry about it. Otherwise I'd top it up. Check the fluid condition also: If it's too black and dirty with burnt smell - your transmission is not going to last. Normally it should be clean and transparent, as in the image. The new fluid comes red. Over the time it becomes brownish. If it is brown, check your owner's manual, may be it's time to change it. Some manufacturers require to change the transmission fluid at 30,000 or 50,000 miles others specify that you never have to change it - check what's your car owner's manual says.

How to top up the transmission fluid:
It's very important to use only specified transmission fluid - check your owners manual or simply visit your local dealer, they alway have proper transmission fluid in stock. Incorrect transmission fluid can even destroy the transmission. Add a small amount of the fluid through the dipstick pipe as shown in the image. Wait for a few minutes - let the fluid to flow down. Recheck the level again. Do not overfill, it also may cause problems with your transmission.

Cummins B Series engine

The Cummins B Series is a family of straight-4 and straight-6 diesel truck and industrial piston engines. The B Series is known for displacing "one liter per cylinder" because of the popular 3.9 L straight-4 and 5.9 L straight-6. A 3.3 L straight-4 is also available. The B Series is widely used in many segments, including pickup trucks (the Dodge Ram), buses, military vehicles, and construction equipment.

The engine was originally designed by Cummins and Case Corporation for commercial truck applications, and appeared in a passenger vehicle, the Dodge Ram, in 1989. It uses a gear-drive camshaft for extra reliability. Also specified is a deep-skirt engine block and extremely strong connecting rods. A Holset turbocharger is used.

The original B Series was updated with 24 valves and an electronic engine management system to become the ISB in 1998.



B5.9

The 5.9 L B5.9 was the first member of the family to be used in a passenger vehicle. Appearing in the 1989 Dodge Ram pickup truck, it quickly became a popular alternative to the large V8 gasoline engines normally used in full-size pickup trucks.

This engine is also used in the Dennis Dart midibus since 1989 as well as usage in light to medium sized commercial trucks and buses.


ISB

The 5.9 L ISB is one of the largest straight-6 engine ever produced for passenger vehicles, and the improved high output 600 version was on the Ward's 10 Best Engines list for 2004.

One unusual feature of the ISB is that it is a multi-valve pushrod engine design. The engine displaces 5883 cc with a 102.1 mm bore and 119.9 mm stroke. A turbocharger output in the high-compression (17.2:1 in recent versions) Diesel. It is an all-iron engine with forged steel connecting rods, an assembled camshaft, and a cast aluminum intake manifold. The engine is produced in Columbus, Indiana.

There have been several versions of the 5.9 L ISB featured in the Dodge Ram. The ISB was first introduced to Dodge Rams in 1989. The Cummins engine in 1991 got an intercooler. In 1994, the engine changed over to a Bosch model P7100 inline-style injection pump from the previous Bosch VE series rotary pump. Midway through model year 1998, The engine was redesigned as a 24 valve model to meet updated emissions requirements and introduced the Bosch VP44 rotary injection pump (featuring electronic control) to the Dodge application. It produced 235 hp (175 kW) at 2700 rpm and 460 ft·lbf (625 Nm) from 1600 rpm to 2700 rpm when paired with a manual transmission, but was slightly downrated when used with automatics.

In 2001, an optional high output (HO) version of the ISB was introduced, producing 245 hp (183 kW) at 2700 rpm and 505 ft·lbf (686 Nm) from 1600 rpm to 2700 rpm when paired with a heavy duty six-speed transmission. The ISB from previous years remained available, and automatic-equipped engines were now rated the same as manuals.

For the 2003 model year, the Cummins was introduced with Bosch high pressure common rail fuel injection, and again, more power. Midway through the 2004 model year, the Cummins 600 was introduced, producing 325 hp (242 kW) at 2900 rpm and 600 ft·lbf (813 Nm)at 1600 rpm. This high torque output gives the engine its name, and also offers a high specific output of 102 ft·lbf (138 Nm) per liter of displacement.

A 610 version, new for the 2005 model year, pushes torque to 610 ft·lbf (827 Nm).


3.9L/4B

The 3.9L/4B Cummins is an excellent high-torque, low-rpm engine in the same family as the 5.9L Cummins turbodiesels. The 3.9L/4B is an inline four-cylinder turbodiesel that was popular for many step van applications including bread vans and other commercial vehicles. This engine is also used in various industrial and construction applications. With a cylinder bore of 4.02 inches and a piston stroke of 4.72 inches, the engine had a wet weight of 745 pounds. In recent years it produced 130hp and 355 lb-ft of torque.


B4.5

The B4.5S is a straight-4 version of the B Series used in agricultural environments. It produces 80–127 hp (60–95 kW). The B4.5 is structurally similar to the six-cylinder B6.7 with both sharing a 104 mm (4.1 in) bore and 132 mm (5.2 in) stroke.


B6.7

The B6.7S is the latest version of the B Series. It is currently the largest straight-6 engine produced for a passenger vehicle. It produces 350 hp (261 kW) and 650 ft·lbf (881 N·m) in the 2007.5 Dodge 2500/3500 pickup trucks and 305 hp (227 kW) and 610 ft·lbf (827 N·m) in the 2007 3500 Chassis Cab. The B6.7 is structurally similar to the four-cylinder B4.5 with both sharing a 104 mm (4.1 in) bore and 132 mm (5.2 in) stroke.

There are many changes over the previous B5.9 for the Dodge truck, the most obvious being the larger displacement. The new engine also includes a cooled EGR system, variable geometry turbocharger, and a new higher-pressure version of the Bosch direct-injection fuel system.

The Dodge trucks' B6.7 competes head to head with V8 engines offered by General Motors and Ford Motor Company, the Duramax and 6.4 L Power Stroke, respectively. All three engines have nearly identical power and torque output specifications and will be released within six months of each other.

Both the B4.5 and B6.7 are used in DAF Trucks' LF45, and LF55 and CF65 range respectively.

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 that has been successfully used on Rich Burn Internal Combustion Engines (typically fueled by petrol but also sometimes fueled by LPG, CNG, or Ethanol) since the middle 1980s will not function at O2 levels in excess of 1.0%, and does not function well at levels above 0.5%. Because of the increasing need to limit NOx emissions from Diesel engines technologies such as Exhaust gas recirculation (EGR) and Selective catalytic reduction (SCR) have been used, however EGR is limited in its effectiveness and SCR requires a reductant, and if the reductant tank is emptied the SCR system ceases to function.

The NOx Adsorber was designed to avoid the problems that EGR and SCR experienced as NOx reduction technologies. The theory is that the zeolite will trap the NO and NO2 molecules - in effect acting as a molecular sponge. Once the trap is full (like a sponge full of water) no more NOx can be adsorbed, and it is passed out of the exhaust system. Various schemes have been designed to "purge" or "regenerate" the adsorber. Injection of diesel fuel (or other reactant) before the adsorber can purge it - the NO2 in particular is unstable and will join with Hydrocarbons to produce H2O and N2. Use of Hydrogen has also been tried, with the same results, however Hydrogen is difficult to store. Some experimental engines have mounted Hydrogen reformers for on board Hydrogen generation, however Fuel Reformers are not mature technology.

NOx Adsorbers are experimental technology as of early 2006, and thus extremely expensive. Whether or not this technology will be successfully commercialized is open to question - only time will tell.


Technical Details

The NOx Adsorber is based on a catalytic converter support that has been coated with a special washcoat containing zeolites.

Ioe engine

The intake over exhaust (IOE) engine, also known as F-head and pocket valve, is a Four-stroke internal combustion engine of primitive design used in early Harley-Davidson motorcycles. The design was also used in other motorcycles, and in car engines by various manufacturers.

The intake valves are "overhead" (located in the cylinder head) and operated by rocker arms and pushrods from the camshaft in the crankcase, while the exhaust valves are flathead (located in the cylinder or engine block) and operated by the camshaft without pushrods or rocker arms. This was a low compression design.

The ioe design allowed the use of much larger valves than a side valve or overhead valve engine, and was still being used in four wheel drive vehicles in the 1960s. (eg CJ-3B Jeep 1953-1964, 1966 Land Rover Six.)

Crower six stroke

The Crower six-stroke engine is a concept under development by Bruce Crower, known for the invention and manufacture of many devices now used in automotive acceleration racing (see National Hot Rod Association and drag racing).

Two extra strokes are added to the customary internal combustion engine four stroke Otto cycle. A fifth down-stroke is a "steam stroke" and the sixth is to exhaust the expanded steam while venting heat from the engine.

The engine cold starts on the Otto cycle, coasting through the fifth and sixth strokes for a short period. After the combustion chamber temperature reaches approximately 400 degrees Fahrenheit ( 200oC ), a mechanical operation phases in the fifth and sixth cycles. Just prior to the fifth-cycle, water is injected directly into the heated combustion chamber via the converted diesel engines fuel injector pump, creating steam and another power stroke. The phase change from liquid to steam removes the excess heat of the combustion stroke forcing the piston down (a second power stroke). As a substantial portion of engine heat now leaves the cylinder in the form of steam, no cooling system radiator is required. Energy that is dissipated in conventional arrangements by the radiation cooling system has been converted into additional power strokes.


Positive aspects:

Crower claims a 40% reduction in fuel consumption and reduced exhaust emissions.

The base engine for modification uses a high compression ratio which is essential for compression ignition. This high ratio is useful in extracting the full potential of ethanol (one of many fuels that this engine may use). These high ratios are a dramatic alteration over present multi-fuel engines which typically use a 10:1 compression ratio, similar to gasoline engines.

The cooler piston top and reduced combustion chamber temperature (heat is extracted in the conversion of injected water to steam) may allow gasoline to be used at very high compression ratios or without environmentally harmful anti-knock chemicals, which are now in universal use with conventional automobile gasoline engine applications. Under these circumstances, far more energy from the gasoline fuel could be converted to horsepower output. (Very high compression ratios are used in racing engines as a means to increase power.)

The weight of most conventional cooling system parts can be eliminated.

The power loss to operate fans and pumps is eliminated.

The mechanical modifications needed to "six-stroke" a small air-cooled industrial diesel already being manufactured are far less complicated than any hybrid system. Many maintenance features of this engine would be parallel or identical to the knowledge base of mechanics well-versed with gasoline, diesel, and racing engines.

The modification to water injection could be done simultaneous to the use of all liquid and gaseous fuels now in widespread use (diesel, gasoline, ethanol, methanol, LP gas, natural gas as well as all plant-derived oils) in the conventional four-stroke portion of the engine.

Physical engine size reduction is possible as one-third of the engine strokes produce power (in the Crower six-stroke), instead of one-quarter (in the Otto cycle).

The higher percentage of power strokes may allow lower operational speeds, with higher torque output at lower and broader rpm ranges. Lower operational speed might allow designs with greater crankshaft diameter, for the use of engine dimensions with inherently more torque potential.

This system is ideal for heavy industrial applications and electric utility peaking plants where "dirty" internal combustion plants are commonly used for stand-by generation.

This is the only "steam engine" that does not require a certified pressure boiler and related hardware complexities, dangers, and weight penalties.


Obstacles or problems:

A warm up period of at least several minutes would be required in all automotive applications. Power is reduced during the warm-up period.

A steam-free cool down period is required to clear water/steam from the engine.

Cold climate anti-freezing electrical resistance heating systems would be required in the mobile water supply.

Water is more dense than all motor fuels.

Oil adulteration, from the water/steam cycle, is an obstacle to be dealt with, though additional piston/cylinder sealing rings can be added easily.

The weight of an oil separator and a water condenser are likely additions.

Current anti-air pollution legislation does not allow for experimental use status on public roadways.

Engine knocking

Knocking (also called pinking or pinging)— colloquially detonation—in internal combustion engines occurs when air/fuel mixture in the cylinder has been ignited by the spark plug and the smooth burning is interrupted by the unburned mixture in the combustion chamber exploding before the flame front can reach it. The engineered combusting process ceases, because of the explosion, before the optimum moment for the four-stroke cycle. The resulting shockwave reverberates in the combustion chamber, creating a characteristic metallic "pinging" sound, and pressures increase catastrophically.



Normal combustion

Under ideal conditions the common piston internal combustion engine burns its fuel air mix in the cylinder in an orderly and controlled fashion. The combustion is started by the spark plug some 15–40 crankshaft degrees prior to TDC (top dead center) the point of maximum compression. This ignition advance allows time for the combustion process to develop peak pressure at the ideal time for maximum recovery of work from the expanding gases. This point is typically 14–18 crankshaft degrees ATDC (after top dead center).

The spark plug produces an electrical spark that jumps a small gap from its center electrode to its ground electrode. This spark, if the air/fuel mix is within the flammable range for the fuel, initiates combustion. The initial phase forms a small kernel of flame approximately the size of the spark plug gap. For the first few milliseconds of the combustion process, this flame kernel is struggling to survive, producing only slightly more heat than is necessary to continue the combustion process. As it grows in size its heat output increases allowing it to grow even faster.

After this early slow burn phase passes, the flame kernel grows much faster expanding rapidly across the combustion chamber. This growth is due to the travel of the flame front through the combustible fuel air mix itself and due to turbulence rapidly stretching the burning zone into a complex of fingers of burning fuel air that have a much greater surface area than a simple spherical ball of flame would have. This greatly accelerates the combustion process.

In normal combustion, this flame front moves throughout the fuel air mix at a rate characteristic for the fuel-air mixture. Pressure rises smoothly to a peak, burning nearly all the available fuel then falls as the piston decends. In normal combustion this produces a rapid increase in cylinder pressure as the piston passes TDC and begins to move down the cylinder. As mentioned above in a properly tuned engine the maximum cylinder pressure is achieved a few crankshaft degrees after the piston passes TDC, so that the increasing pressure can give the piston a hard push when its speed and mechanical advantage on the crank shaft gives the best recovery of force from the expanding gases.


Detonation

The fuel/air mixture is normally ignited slightly before the point of maximum compression to allow a small time for the flame-front of the burning fuel to expand throughout the mixture so that maximum pressure occurs at the optimum point. The flame-front moves at roughly 33.5 m/second (110 feet/second) during normal combustion[citation needed]. It is only when the remaining unburned mixture is heated and pressurized by the advancing flame front for a certain length of time that the detonation occurs. It is caused by an instantaneous ignition of the remaining fuel/air mixture in the form of an explosion. The cylinder pressure rises dramatically beyond its design limits and if allowed to persist detonation will damage or destroy engine parts.

Detonation can be prevented by:

* The use of a fuel with higher octane rating

* The addition of octane-increasing "lead", methylcyclopentadienyl manganese tricarbonyl (MMT), isooctane, or other antiknock agents.

* Increasing the amount of fuel injected/inducted (resulting in lower Air to Fuel Ratio)

* Reduction of cylinder pressure by increasing the engine revolutions (lower gear), decreasing the manifold pressure (throttle opening) or reducing the load on the engine, or any combination.

* Reduction of charge (in-cylinder) temperatures (such as through cooling, water injection or compression ratio reduction).

* Retardation of spark plug ignition.

* Improved combustion chamber design that concentrates mixture near the spark plug and generates high turbulence to promote fast even burning.

* Use of a spark plug of colder heat range in cases where the spark plug insulator has become a source of pre-ignition leading to detonation.

Correct ignition timing is essential for optimum engine performance and fuel efficiency. Modern automotive and small-boat engines have sensors that can detect knock and retard (delay) the ignition (spark plug firing) to prevent it, allowing engines to safely use petrol of below-design octane rating, with the consequence of reduced power and efficiency.

A knock sensor consists of a small piezoelectric microphone, on the engine block, connected to the engine's ECU. Spectral analysis is used to detect the trademark frequency produced by detonation at various RPM. When detonation is detected the ignition timing is retarded, reducing the knocking and protecting the engine. See also Automatic Performance Control (APC).


Pre-ignition

Pre-ignition is a different phenomenon from detonation, explained above, and occurs when the air/fuel mixture in the cylinder (or even just entering the cylinder) ignites before the spark plug fires. Pre-ignition is caused by an ignition source other than the spark. Heat or hot spots can buildup in engine intake or cylinder components due to improper design, for example, spark plugs with heat range too hot for the conditions, or due to carbon deposits in the combustion chamber. Spark plugs with a high heat range will run hot enough to burn off deposits that lead to plug fouling in a worn engine, but the electrode of the plug itself can occasionally heat soak, and begin glowing hot enough to become an uncontrolled ignition source on its own. Bits of carbon that build up in a combustion chamber can also heat soak to the point where they also are glowing hot and ignite the air-fuel mixture before the proper time.

Pre-ignition and "dieseling" or "run on" are the same phenomenon, except in the latter case the engine continues to run after the ignition is shut off with a hot spot as an ignition source. Pre-ignition might cause rough running due to the advanced and erratic effective igniton timing and may cause noise if it leads to detonation. It may also cause "rumble" which is fast and premature but not detonating combustion.

This heat buildup can only be prevented by eliminating the overheating (through redesign or cleaning) or the compression effects (by reducing the load on the engine or temperature of intake air). As such, if pre-ignition is allowed to continue for any length of time, power output and fuel economy is reduced and engine damage may result. The engine might be slightly harder to get running at once after pre-ignition.

Pre-ignition may lead to detonation and detonation may lead to pre-ignition or either may exist separately.

BMC E-Series engine

The BMC E-Series was a straight-4 and straight-6 overhead camshaft automobile engine. It displaced 1.5 litres or 1.8 litres in 4 cylinder and 2.2 litres and 2.7 litres as a 6 cylinder. Although designed when the parent company was BMC, by the time the engine was launched the company had become British Leyland. The engine was eventually replaced by the R-Series, and the S-series in the mid 1980s.




Automobiles using the E-Series

Examples of cars using a version of the E series engine:

* Austin Maxi
* Austin Allegro
* Leyland Princess 2200 cc models, plus Wolseley 2200, Austin 2200 and Morris 2200 badge-engineered versions.
* Leyland Marina
* British Leyland P76
* Rover SDX
* Morris Nomad
* Austin Kimberly
* Austin Tasman



Engine Types

1.5 litre engines

The 1.5 L (1485 cc) version was first used in the Austin Maxi 1969. Output was 69 bhp (524 kW). Bore was 76.2 mm and stroke was 81.3 mm.

Applications:

* Austin Maxi
* Austin Allegro
* Morris Marina


1.8 litre engines

The engine was enlarged to 1748 cc in 1971 by increasing the stroke to 95.75 mm .

Applications:

* Austin Maxi
* Austin Allegro
* Leyland Marina


2.2 litre engines

The 2227 cc version was created by adding two cylinders to the 1.5 litre engine. Bore and stroke remained at the 76 km and 81 km of the 1500 cc version. It was last made in 1982.

Applications:

* Leyland Princess
* Austin Kimberley
* Wolseley 2200


2.6 litre engines

The 2622 cc version was created by increasing the stroke to the 95.75 km used in the 1750 cc version. The power output was 121 bhp and torque 165 ft·lbf.

Applications:

* Leyland P76 (Australia)
* Morris Marina (Australia)
* Rover SDX (South Africa)

BMW 247 engine

The BMW 247 is an air-cooled flat twin motorcycle engine, also known as the "Airhead Boxer". It was used by BMW in its motorcycles from 1969 to 1995.

The /5 was introduced in 1969. The /6 was introduced in 1974. The /7 was introduced in 1977.

Before 1981 the ignition was points ignition. From 1981 it used electronic ignition, a lighter flywheel and was slower.

A number of different models were on the market:

* S: with the most famous BMW R90S R90S who was as fast as the Porsche Boxer in acceleration.
* CS: The Classic Sport, with a 1000cc engine.
* LS: 650cc sport
* ST: An 800cc road-styled GS.
* RS: Racing Sport
* RT: Road Touring
* GS: Gelände/Strasse or Gelände Sport depending on model - many times the winner of the Paris-Dakar rally.

BMW build other air cooled flat twin engines as the 248/1-type used for the R65. Before that they built side-valved and OHV engines commencing with the R32 of 1923. Perhaps the most famous was the R75, the 2WD sidecar motorcycle used by the Wehrmacht in World War II on the African and Eastern fronts.

After World War II, BMW was in a rebuilding period and did not produce any motorcycles in the Allied sector for 1945-1947 and only 59 for 1948.

Air-fuel ratio meter

A meter monitoring the air-fuel ratio of a combustion engine. Also called air-fuel ratio gauge or simply air-fuel meter or air-fuel gauge. It reads the voltage output of an oxygen sensor, sometimes also called lambda sensor, whether it be from a narrow band or wide band oxygen sensor.

The original narrow band sensors became car factory installed standard in the late 70's and early 80's. In recent years, a newer and much more accurate 'wide band' sensor, though more expensive, has come to availability.

Since there are two types of sensors, there are two types of meters, narrow band and wide band.

Most stand-alone narrow band meters have 10 leds and some have more. Also common, narrow band meters in round housings with the standard mounting 2 1/16" and 2 5/8" diameters, as other types of car 'gauges'. These usually have 10 or 20 leds. Analogue 'needle' style gauges are also available.

As stated above, there are wide band meters that stand alone or are mounted in housings. Nearly all of these show the air-fuel ratio on a numeric display, since the wide band sensors provide a much more accurate reading. And since they use more accurate electronics, these meters are more expensive.



Benefits of air-fuel ratio metering.

* Determining the condition of the oxygen sensor: A malfunctioning oxygen sensor will result in air-fuel ratios which respond more slowly to changing engine conditions. A damaged or defective sensor may lead to increased fuel consumption and increased pollutant emissions as well as decreased power, and throttle response.

* Reducing emissions: Keeping the air-fuel mixture near the stoichometric ratio of 14.7:1 (for gasoline engines) allows the catalytic converter to operate at maximum efficiency.

* Fuel economy: An air-fuel mixture at the stoichometric ratio will result in near optimum fuel mileage, costing less per mile traveled and producing the least amount of CO2 emissions. However, from the factory, cars are designed to operate at the stoichometric ratio (rather than as lean as possible while remaining driveable) in order to maximize the efficiency and life of the catalytic converter. While it may be possible to run smoothly at leaner mixtures than 14.7:1, manufacturers must focus on emissions and especially catalytic converter life (which must now be 100,000 miles on new vehicles) {fact} as a higher priority due to EPA regulations.

* Engine performance: Carefully mapping out air-fuel ratios throughout the range of rpm and manifold pressure will maximize power output in addition to reducing the risk of detonation.

Lean mixtures improve the fuel economy but also cause sharp rises in the amount of nitrogen oxides (NOX). If the mixture becomes too lean, the engine may fail to ignite, causing misfire and a large increase in unburned hydrocarbon (HC) emissions. Lean mixtures burn hotter and may cause rough idle, hard starting and stalling, and can even damage the catalytic converter, or burn valves in the engine. The risk of spark knock/engine knocking (detonation) is also increased when the engine is under load.

Mixtures that are richer than stoichometric are necessary when the engine is under heavy load, especially under wide open throttle. The ideal mixture in this type of operation depends on the individual engine. For example, engines using forms of forced induction such as turbochargers and superchargers typically require a richer mixture under wide open throttle than naturally aspirated engines.

Cold engines also typically require more fuel and a richer mixture when first started, because fuel does not vaporize as well when cold, and because cold air is denser, and therefore requires more fuel to properly "saturate" it. Rich mixtures also burn cooler and decrease the risk of spark knock/engine knocking (detonation) when the engine is under load. However, rich mixtures sharply increase carbon monoxide (CO) emissions.


Oxygen sensor types.

Oxygen sensors are installed in the exhaust system of the vehicle, attached to the engine's exhaust manifold, the sensor calculates the ratio of the air-fuel mixture.

As mentioned above, there are two types of sensors available; narrow band, and wide band. Narrow band sensors were the first to be introduced. The wideband sensor was introduced much later.

A narrow band sensor has a non-linear output, and switches between the thresholds of lean (ca 100-200 mV) and rich (ca 650-800 mV) areas very steeply.

Also, narrow band sensors are temperature-dependent. If the exhaust gases become warmer, the output voltage in the lean area will rise, and in the rich area it will be lowered. Consequently, an oxygen sensor, without pre-heating, has a lower lean-output and a higher rich-output, possibly even exceeding 1 Volt. The influence of temperature to voltage is smaller in the lean mode than in the rich mode. A "cold" engine makes the sensor switch the output voltage between ca 100 and 850/900 mV and after a while the sensor may output a switch voltage between ca 200 and 700/750mV, for turbocharged cars even less.

The ECU tries to maintain a stoichiometric balance, wherein the air-fuel mixture is approximately 14.7 times the mass of air to fuel. This, in order to maintain a neutral engine performance (lower fuel consumption yet decent engine power and minimal pollution.).

The average level of the sensor is defined as 450 mV. Since narrow band sensors cannot output a fixed voltage level between the lean and the rich areas, the ecu tries to control the engine by controlling the mixture between lean and rich in such a sufficiently fast manner, that the average level becomes ca 450 mV. Mixtures that are less than 14.7 to 1 are rich, and more than 14.7 to 1 are lean.

A wideband sensor, on the other hand, has a very linear output, 0 - 5 V, and is not temperature dependent.


Which type of air-fuel ratio meter to be used.

If the purpose of the air-fuel ratio meter is to diagnose an existing or possible problem with the sensor and/or to check the general mixture, and performance, a narrow band air-fuel ratio meter is sufficent.

In high-performance tuning applications, however, the wide-band system is desireable.

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 both on other machinery and on the 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.


Inherent mechanical balance

The mechanical balance of a piston engine is one of the key considerations in choosing an engine configuration.


Primary and secondary balance

Historically, engine designers have spoken of primary balance and secondary balance. These terms generally refer to the order in which the problems of engine balance were addressed as piston engines developed. Because of this they also to some degree reflect the importance of these aspects of balance, but not absolutely, nor do they cover all aspects of mechanical balance.

The definitions used of primary and secondary balance also vary. In general, primary balance is the balance achieved by compensating for the varying momentum (but not the varying kinetic energy) of the pistons during rotation of the crankshaft. Secondary balance can include compensating (or being unable to compensate) for:

* The kinetic energy of the pistons.
* The non-sinusoidal motion of the pistons (which may otherwise be regarded as part of primary balance).
* The sideways motion of crankshaft and balance shaft weights.
* Various rocking motions produced by displacement of balancing masses and not included as primary balance (such as the unwanted offset of opposing cylinders in the boxer engine necessitated by the crankshaft design).

Despite claims by designers and manufacturers, no configuration is perfectly balanced. However by adopting particular definitions for primary and secondary balance, particular configurations can be correctly claimed to be perfectly balanced in these restricted senses. That is not to say that there is no substance to these claims. In particular, the straight six, the flat six, and the V12 configurations offer exceptional inherent mechanical balance.

Vibrations not normally included in either primary or secondary balance include the uneven firing patterns inherent in some configurations. Many definitions of secondary balance also exclude some aspects of mechanical balance.


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.


Steam engines

The question of mechanical balance was addressed on steam engines long before the invention of the internal combustion engine. Steam locomotives commonly have balancing weights on the driving wheels to control wheel hammer caused by the up and down motion of the tie rods and to some degree the connecting rods. Again, the balance is a compromise, and some main line locomotives such as the Australian 38 class have no such weights.


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.


Blueprinting

Blueprinting is the remachining of components to tighter tolerances to achieve better balance.

Ideally, blueprinting is performed on components removed from the production line before normal balancing and finishing. If finished components are blueprinted, there is the risk that the further removal of material will weaken the component. However, lightening components is generally an advantage in itself provided balance and adequate strength are both maintained, and more precise machining will in general strengthen a part by removing stress points, so in many cases performance tuners are able to work with finished components.


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.

Belt alternator starter

General Motors introduced a mild hybrid system called belt alternator starter (or BAS) in the 2006 Saturn VUE Green Line. It operates similar to the "start-stop" system used in the Chevrolet Silverado Hybrid in that it shuts down the engine when the vehicle comes to a stop and instantly restarts it when the accelerator is pressed. A 48 volt electrical system is used to operate all accessory equipment, from the air conditioning to the lighting, making the system essentially invisible to the driver.

The BAS system goes slightly further than the Silverado, however, in providing some modest power assist for "acceleration feel", according to GM. Although not as effective as other systems, the BAS system is expected to provide about 15% fuel efficiency gain for the compact VUE.

One major benefit of the BAS technology is that it fits in the same space as a conventional engine. No modifications were required to the VUE's chassis to accommodate the BAS system, with the battery pack housed in the spare tire well. This allows the VUE Green Line to be produced on the same assembly line as the normal VUE, producing substantial cost savings and allowing the company to adjust production more easily.

The BAS system uses a conventional 4T45-E automatic transmission.

This system will eventually find its way to other GM models, including the Saturn Aura, and Chevrolet Malibu.

Multi-Displacement System

DaimlerChrysler's Multi-Displacement System (MDS) is an automobile engine variable displacement technology. It debuted in 2004 on the 5.7 L modern Hemi V8. Like Mercedes-Benz's Active Cylinder Control, General Motors' Displacement on Demand, and Honda's Variable Cylinder Management, it deactivates four of the V8's cylinders when the throttle is closed.

The system was first offered only on passenger cars, since the heavy demands of trucks would interfere with its operation. However, it was recalibrated for 2006 and will be offered on all seven models, including trucks, using the 5.7 L engine.

Chrysler expects that the technology will boost economy by 10% to 20%. In the Jeep Grand Cherokee with MDS, highway fuel mileage for the V8 is the same as the V6 at 21 mpg (11.2 liters per 100 km).

In order to preserve the characteristic rumble of the V8 engines, Chrysler and Eberspaecher North America designed a special exhaust system for MDS-equipped vehicles. This includes four separate mufflers, two large central ones for V8 mode and two smaller ones near the tailpipes for straight-4 operation. Unlike the system used on Mercedes-Benz V12 engines, also designed by Eberspaecher, the system is mechanically passive.

Applications:

* 2005- Chrysler 300C
* 2005- Dodge Charger
* 2005- Dodge Magnum
* 2005- Jeep Grand Cherokee
* 2006- Dodge Durango
* 2006- Dodge Ram
* 2006- Jeep Commander

Power band

The power band of an engine refers to the range of operating speeds under which the engine is able to operate efficiently. A typical gasoline automotive engine is capable of operating at a speed of between around 750 and 6000 RPM, but the engine's power band would be more limited. The engine would typically not generate maximum torque until higher operating speeds of perhaps 2500 RPM, after such, the torque drops off. The peak power (horsepower) might be closer to 5000 RPM. Such an engine would be said to have a "power band" of 2500-5000 RPM (another example would be from torque peak to redline: 2500-6000 RPM).

A more precise definition of the power band: the rpm range where an engine makes at least 75% of its maximum torque.

This can be applied to any engine and establishes a reliable quantification of the above notion "the engine is able to operate efficiently".



Power Band Tuning Considerations

The tuning of the power band is a great challenge. It is possible to create a peaky engine which generates more power from an engine if the manufacturer is willing to tune it for a very narrow power band. However, an engine with a narrow power band is more difficult to use. Such an engine must be coupled to a close-ratio transmission with many gears in order to remain in its power band while providing an acceptably wide range of output speeds. A flexible engine has a wide power band with less peak power, but could be tied to a less complex transmission with fewer gears and would not need to shift gears as often. Such an engine is also often called torquey because it maintains a more constant level of torque over a wider range of RPM.


Cost and Usage Considerations

Sports cars and other performance vehicles are generally designed for peak power in a narrow power band. In these vehicles, the higher cost of a complex transmission would be more acceptable, and the driver could be assumed to be more willing to shift gears often to remain in the power band. These vehicles attempt to achieve the greatest possible power to weight ratio, and benefit greatly from using a smaller engine tuned for high peak power rather than a large engine with a wide power band. Trucks and full-size cars are more often tuned for a wide power band and use larger engines to achieve acceptable power over a wide range. These vehicles have the benefit of not having to shift as often as vehicles with a narrow power band.


Tuning for high Horsepower Output or high Torque Output?

Since automobile shoppers rely heavily on the peak power output figure (typically given in horsepower or kilowatts), some auto makers tend towards producing "peaky" engines. For example, Honda's 2006 Civic Si generates 197 hp (147 kW) at 7800 RPM. Though it produces a fairly flat torque curve compared to many engines, it only produces 139 ft·lbf (188 N·m) and it has relatively sharp (or "peaky") power delivery, this requires the driver to keep the engine at high RPM to extract the best performance from the Civic. In contrast, Volkswagen's 2006 GTI 2.0T produces about 200 hp (149 kW) from 5,100 RPM to 6,000 RPM and a relatively flat torque band of 207 ft·lbf (281 N·m) from 1,800 to 5,000 RPM. This wide power delivery makes it easier for the driver to extract the vehicles best performance.


Power band considerations with a CVT vehicle

Because a CVT vehicle has the capability of keeping RPMs within the crest of the power band under acceleration, a peaky engine is optimal. Under full acceleration 100% of the available power can be extracted at all times. There is no shifting, and no moving out of the power band. This type of transmission is more efficient than others due to power band issues mentioned previously, but is not favored by many due to the lack of apparent power. Drivers are accustomed to the sudden lurch off the line and the shifting of the transmission. Though these are only actions of less efficient transmission, some vehicle manufacturers have computerized such events in to the transmission to add to the perception of power and torque.


Non-Automotive Power Band Tuning

Engines for ships and aircraft are also generally designed with a narrow power band as these vehicles do not have to operate over a wide speed range. They instead reach their optimal operating speed and remain there for the duration of their trips. As a result, they benefit from tuning for peak power and efficiency in a narrow power band.

Injection pump

An Injection Pump is the device that pumps fuel into the cylinders of a diesel engine or less typically, a gasoline engine. Traditionally, the pump is driven indirectly from the crankshaft by gears, chains or a toothed belt (often the timing belt) that also drives the crankshaft on overhead-cam engines (OHC). It rotates at half crankshaft speed in a conventional four-stroke engine. Its timing is such that the fuel is injected only very slightly before top dead-centre of that cylinder's compression stroke. It is also common for the pump belt on gasoline engines to be driven directly from the camshaft.

Because of the need for positive injection into a very high-pressure environment, the pump develops great pressure—typically 15,000 psi (100 MPa) or more on newer systems. This is a good reason to take great care when working on diesel systems; escaping fuel at this sort of pressure can easily penetrate skin and clothes, and be injected into body tissues with serious consequences.

Earlier diesel pumps used an in-line layout with a series of cam-operated injection cylinders in a line, rather like a miniature inline engine. The pistons have a constant stroke volume, and injection volume (ie, throttling) is controlled by rotating the cylinders against a cut-off port that aligns with a helical slot in the cylinder. When all the cylinders are rotated at once, they simultaneously vary their injection volume to produce more or less power from the engine. Inline pumps still find favour on large multi-cylinder engines such as those on trucks, construction plant, static engines and agricultural vehicles.

For use on cars and light trucks, the rotary pump or distributor pump was developed. It uses a single injection cylinder driven from an axial cam plate, which injects into the individual fuel lines via a rotary distribution valve. Later incarnations such as the Bosch VE pump vary the injection timing with crank speed to allow greater power at high crank speeds, and smoother, more economical running at slower revs. Some VE variants have a pressure-based system that allows the injection volume to increase over normal to allow a turbocharger or supercharger equipped engine to develop more power under boost conditions.

All injection pumps incorporate a governor to cut fuel supply if the crank speed endangers the engine - the heavy moving parts of diesel engines do not tolerate overspeeding well, and catastrophic damage can occur if they are over-revved.

Mechanical pumps are gradually being phased out in order to comply with international emissions directives, and to increase performance and economy. Alternatives include common rail diesel systems and unit direct injection systems. These allow for higher pressures to be developed, and for much finer control of injection volumes compared to mechanical systems.

Catalytic Converter Technical Details

The catalytic converter consists of several components:

1. The core, or substrate. In modern catalytic converters, this is most often a ceramic honeycomb, however stainless steel foil honeycombs are also used. The purpose of the core is to "support the catalyst" and therefore it is often called a "catalyst support". The ceramic substrate was invented by Rodney Bagley, Irwin Lachman and Ronald Lewis at Corning Glass for which they were inducted into the National Inventors Hall of Fame in 2002.

2. The washcoat. In an effort to make converters more efficient, a washcoat is utilized, most often a mixture of silicon and aluminium. The washcoat, when added to the core, forms a rough, irregular surface which has a far greater surface area than the flat core surfaces, which is desirable to give the converter core a larger surface area, and therefore more places for active precious metal sites. The catalyst is added to the washcoat (in suspension) before application to the core.

3. The catalyst itself is most often a precious metal. Platinum is the most active catalyst and is widely used. However, it is not suitable for all applications because of unwanted additional reactions and/or cost. Palladium and rhodium are two other precious metals that are used. Platinum and rhodium are used as a reduction catalyst, while platinum and palladium are used as an oxidization catalyst. Cerium, iron, manganese and nickel are also used, though each has its own limitations. Nickel is not legal for use in the European Union (due to nickel hydrate formation). While copper can be used, its use is illegal in North America due to the formation of dioxin.


Rich Burn Spark Ignition Engines

Catalytic converters are used on spark ignition (gasoline; liquified petroleum gas (LPG); flexible fuel vehicles burning varying blends of E85 and gasoline; compressed natural gas (CNG)) engines; and compression ignition (diesel) engines.

For spark ignition engines the most commonly used catalytic converter is the three-way converter, which works best used on engines equipped with closed-loop feedback fuel mixture control employing an oxygen (lambda) sensor. While a 3-way catalyst can be used in a open-loop system (and has been for years in the non-road engine market), NOx conversions tend to be less than stellar - and since World emissions regulations are primarily aimed at NOx reduction, open loop fuel systems are now obsolete. To keep the air fuel ratio at stoichiometric (14.7:1 for gasoline), closed loop fuel systems are either fuel injection or a carburetor equipped for feedback mixture control. Within that band, conversions are very high, sometimes approaching 100%. However, outside of that band, conversions tend to fall off very rapidly (see bell curve). Two-way converters have been abandoned on spark ignition engines, due to an inability to control NOx.

A three-way catalyst reduces emissions of CO (carbon monoxide), HC (hydrocarbons), and NOx (nitrogen oxides) simultaneously when the oxygen level of the exhaust gas stream is below 1.0%, though performance is best at below 0.5% O2. Unwanted reactions, such as the formation of H2S (hydrogen sulfide) and NH3 (ammonia), can occur in the three-way catalyst. Formation of each can be limited by modifications to the washcoat and precious metals used. It is, however, difficult to eliminate these side products entirely.

For example, when control of H2S (hydrogen sulfide) emissions is desired, nickel or manganese is added to the washcoat - both substances act to block the adsorption of sulfur by the washcoat. H2S is formed when the washcoat has adsorbed sulfur during a low temperature part of the operating cycle, which is then released during the high temperature part of the cycle and the sulfur combines with HC. For "lean burn" spark ignition engines (e.g. compressed natural gas, or compressed natural gas with diesel fuel pilot injection), an oxidation catalyst is used in the same manner as in a compression ignition engine.

Recently, systems have used a separate early catalytic converter in the system to reduce startup emissions and burn off the hydrocarbons from the extra-rich mixture used in a cold engine. Also, upstream and downstream parts are now often separated in the system to provide an optimum temperature and space for extra oxygen sensors. The converter needs to be placed close enough to the engine to quickly reach operating temperature but far enough away to avoid heat damage.

Early three-way catalytic converters utilized an air tube between the first part of the converter (the NOx part) and the second part, which is virtually unchanged from earlier two-way catalytic converters. This tube was fed by either an air pump (derived from the earlier A.I.R. systems) or by a Pulse Air system. The extra oxygen was used to offset the less precise control of earlier systems by providing the oxygen for the catalyst's oxidizing reaction. The first section was still prone to difficulties on lean conditions with too much oxygen for the NOx reduction to be complete, but the second section always had oxygen available. These systems also commonly included an upstream air injector, either a modified A.I.R. system or another opening in the manifold, to add oxygen into the system to burn the extra-rich mixture used in a cold engine and to allow the additional burning to happen as close to the converter as possible to heat it up to operating temperature quickly.

Newer systems use several techniques to avoid the air tubes. They provide a constantly varying mixture that quickly cycles lean and rich mixtures to keep the first catalyst (NOx reduction) from becoming oxygen loaded and the second catalyst (CO oxidization) sufficiently oxidized, which is less of a concern due to the oxygen created in the first section. They also utilize several oxygen sensors to monitor the exhaust, at least one before the catalytic converter for each bank of cylinders, and one after the converter. Newer systems also often have several units mounted along the pipe to provide different functions rather than one monolithic system.


Diesel Engines

For compression ignition (i.e., Diesel) engines, the most commonly used catalytic converter is the diesel oxidation catalyst. The catalyst uses excess O2 (oxygen) in the exhaust gas stream to oxidize CO (Carbon Monoxide) to CO2 (Carbon Dioxide) and HC (hydrocarbons) to H2O (water) and CO2. These converters often reach 90% effectiveness, virtually eliminating diesel odor and helping to reduce visible particulates (soot), however they are incapable of reducing NOx as chemical reactions always occur in the simplest possible way, and the existing O2 in the exhaust gas stream would react first.

To reduce NOx on a compression ignition engine it is necessary to change the exhaust gas - two main technologies are used for this - selective catalytic reduction (SCR) and NOx (NOx) traps (or NOx Adsorbers).

Another issue for diesel engines is particulate (soot). This can be controlled by a soot trap or diesel particulate filter (DPF), as catalytic converters are unable to affect elemental carbon (however they will remove up to 90% of the soluble organic fraction). A clogging soot filter creates a lot of back pressure decreasing engine performance. However, once clogged, the filter goes through a regeneration cycle where diesel fuel is injected directly into the exhaust stream and the soot is burned off. After the soot has been burned off the regeneration cycle stops and injection of diesel fuel stops. This regeneration cycle will not affect performance of the engine.

All major diesel engine manufacturers in the USA (Ford, Caterpillar, Cummins, Volvo, MMC) starting January 1, 2007 are required to have a catalytic converter and a soot filter inline, as per a new DoT legislation.


Oxygen storage

In order to oxidize CO and HC, the catalytic converter also has the capability of storing the oxygen from the exhaust gas stream, usually when the air fuel ratio goes lean. When insufficient oxygen is available from the exhaust stream the stored oxygen is released and consumed. This happens either when oxygen derived from NOx reduction is unavailable or certain maneuvers such as hard acceleration enrich the mixture beyond the ability of the converter to compensate.

Catalyst poisoning and deactivation

Catalytic converters become ineffective in the presence of lead due to catalyst poisoning. Therefore, vehicles equipped with catalytic converters must only be run on unleaded gasoline, and it is this fact, as much as concerns about the possibly harmful effects of lead emissions, which caused the end of pump-available leaded gasoline in countries where catalytic converters have been in common use for many years. Leaded "race only" fuel is still used for non-catalyst vehicles in some countries where it is no longer legal for road use. Catalyst poisoning occurs when a substance in the engine exhaust coats the surface of the catalyst, preventing further exhaust access to the catalytic materials. Poisoning can sometimes be reversed by running the engine under a very heavy load for an extended period of time to raise exhaust gas temperature, which may cause liquefaction or sublimation of the catalyst poison. Common catalyst poisons are lead, sulfur, zinc, manganese, silicon and phosphorus.

Zinc, phosphorus and sulfur originate from lubricant antiwear additives such as ZDDP; sulfur and manganese primarily originate from fuel impurities or from additives such as Methylcyclopentadienyl Manganese Tricarbonyl (MMT), respectively. Silicon poisoning in automotive applications is the result of engine damage, such as a faulty cylinder head gasket or cracked casting, admitting silicate-containing coolant into the combustion chamber. In stationary engines silicon poisoning is more often caused by the use of "Landfill" gas as a fuel.

Removal of sulfur from a catalyst surface by running heated exhaust gases over the catalyst surface is often successful; however, removal of lead deposits in this manner is usually not possible because of lead's high boiling point. In particularly bad cases of catalyst poisoning by lead, the catalytic converter can actually become completely plugged with lead residue.

A variety of conditions may cause the catalyst to overheat (heat deactivation) and potentially to melt down. Some factors that can cause this are:

* lubricating oil in the exhaust system (caused by engine wear, or by damaged rings or valves)

* an engine misfire or ignition failure (causing unburnt fuel to enter the exhaust)

* a cracked exhaust valve (again, causing unburnt fuel in the exhaust)

Overly rich fuel mixtures are not usually a problem - there is too little unused oxygen for the exotherm to be large enough to cause damage. A slightly lean of stoichiometric mix is far more dangerous, as the oxygen level is elevated, allowing a very large exotherm, and many engine manufacturers design "rich excursions" as a catalyst protection measure in the engine control software. In the early days of catalyst-equipped cars, (primarily in the USA) before the advent of sophisticated engine management systems, it was necessary for fuel/air mixtures to be significantly richer than had hitherto been the case to allow the catalyst to work effectively. This contributed to the very poor fuel consumption figures achieved by such cars.

Engine misfires can overheat and destroy the converter as the excessive amounts of unburned fuel are broken down within it, especially when the engine is under heavy loads. Vehicles equipped with OBD-II diagnostic systems are designed to alert the driver of a misfire condition, along with other malfunctions, using the Malfunction Indicator Lamp or "Check Engine" light. If the misfire and engine load can produce heating severe enough to cause catalyst damage, the MIL will flash until the misfire or engine load is reduced.

Catalytic converter

A catalytic converter (colloquially, "cat" or "catcon") is a device used to reduce the toxicity of emissions from an internal combustion engine. First widely introduced on series-production automobiles in the US market for the 1975 model year to comply with tightening EPA regulations on auto exhaust, catalytic converters are still most commonly used in motor vehicle exhaust systems. Catalytic converters are also used on generator sets, forklifts, mining equipment, trucks, buses, trains, and other engine-equipped machines. A catalytic converter provides an environment for a chemical reaction wherein toxic combustion by-products are converted to less-toxic substances.



Functions


Three-way catalytic converters

A three-way catalytic converter has three simultaneous tasks:

1. Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2
2. Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2
3. Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: 2CxHy + (2x+y/2)O2 → 2xCO2 + yH2O

These three reactions occur most efficiently when the catalytic converter receives exhaust from an engine running at the stoichiometric point. This is 14.7 parts oxygen to 1 part fuel, by weight, for gasoline (the ratio for LPG, natural gas and ethanol fuels is slightly different, requiring modified fuel system settings when using those fuels). When there is more oxygen than required, then the system is said to be running lean, and the system is in oxidizing condition. In that case, the converter's two oxidizing reactions (oxidation of CO and hydrocarbons) are favoured, at the expense of the reducing reaction. When there is excessive fuel, then the engine is running rich. The reduction of NOx is favoured, at the expense of CO and HC oxidation. If an engine could be held at the strict stoichiometric point for the fuel used, it is theoretically possible to reach 100% conversion efficiencies.

Since 1981, three-way catalytic converters have been at the heart of vehicle emission control systems in North American roadgoing vehicles and are also used on "Large Spark Ignition" engines. LSI engines are used in forklifts, aerial boom lifts, ice resurfacing machines and construction equipment. The converters used in these are three-way types designed to reduce combined NOx+HC emissions from 12 gram/BHP-hour to 3 gram/BHP-hour or less, per the Environmental Protection Agency (EPA) 2004 regulations. A further drop to 2 gram/BHP-hour of NOx+HC emissions is mandated in 2007 (note: NOx is the industry standard short form for nitric oxide (NO) and nitrogen dioxide (NO2) both of which are smog precursors. HC is the industry short form for hydrocarbons). The EPA intends to introduce emissions rules for stationary Spark Ignition engines, to take effect in January 2008.


Two-way catalytic converters

A two-way catalytic converter has two simultaneous tasks:

1. Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2
2. Oxidation of unburnt hydrocarbons (unburnt and partially-burnt fuel) to carbon dioxide and water: 2CxHy + (2x+y/2)O2 → 2xCO2 + yH2O

This type of catalytic converter is widely used on diesel engines to reduce hydrocarbon and carbon monoxide emissions. They also were used on spark ignition (gasoline) engines in USA market automobiles up until 1981, when they were replaced by three-way converters due to regulatory changes requiring reductions on NOx emissions.

Curiously, the regulations regarding hydrocarbons vary according to the engine regulated, as well as the jurisdiction. In some cases, "non-methane hydrocarbons" are regulated, while in other cases, "total hydrocarbons" are regulated. Technology for one application (to meet a non-methane hydrocarbon standard) may not be suitable for use in an application that has to meet a total hydrocarbon standard. Methane is more difficult to break down in a catalytic converter, so in effect a "non-methane hydrocarbon" standard can be considered to be looser. Since methane is a greenhouse gas, more interest is rising in how to eliminate emissions of it.

Gasoline direct injection

Gasoline direct injection or GDi is a variant of fuel injection employed in modern two-stroke and four stroke petrol engines. The gasoline or biobutanol is injected right into the combustion chamber of each cylinder, as opposed to conventional multi point fuel injection that happens in the intake manifold, or cylinder port injection in two-strokes.

GDi enables stratified charge (ultra lean burn) combustion for improved fuel efficiency and emission levels at low load. Further improving efficiency and high-load output-power, the engine power is governed by modulating fuel injection, like a diesel engine; as opposed to restricting intake airflow, like a conventional gas internal combustion engine.



Theory of operation

The major advantages of a GDi engine are increased fuel efficiency and high power output. This is achieved by the precise control over amount of fuel and injection timings which are varied according to the load conditions. In addition, there are no throttling losses when compared to a conventional fuel injected or carburated engine, which greatly improves efficiency (only in engines that are using no throttle plate). Basically, the engine management system continuously chooses between three different modes of combustion: ultra lean burn combustion, stoichiometric combustion, and high power output mode.

Each mode is characterized by air-fuel ratio, the amount of fuel in the air-fuel mixture; the stoichiometric ratio for petrol is 14.7 to 1 by weight, but in ultra lean mode, it could be as high as 65 to 1. These are leaner mixtures than those ever achieved in the conventional engines are desired because of reduced fuel consumption.

* Ultra lean combustion mode is effective under normal running conditions, when little acceleration is required. The fuel is not injected at the intake stroke but rather at the latter stages of the compression stroke, so that the small amount of air-fuel mixture is optimally placed just near the spark plug. This stratified charge is surrounded by mostly air which keeps the fuel away from the cylinder walls for lowest emissions. The combustion takes place in a toroidal cavity on the piston's surface. This technique enables the usage of ultra lean mixtures with very high air-fuel ratio, impossible with traditional carburetors or even intake port injection.

* Stoichiometric combustion mode is activated for moderate load conditions. In this mode, fuel is injected during the intake stroke. The air-fuel mixture is homogeneous with the stoichiometric rates necessary for the catalytic converter to remove a maximum of the major pollutants CO and NOx from the exhaust gas.

* In full power mode, the air-fuel mixture is homogeneous as well and contains the minimum mass of fuel over the amount required for stoichiometric that is possible to ignite without knocking out, as defined by the compression ratio of the engine and the mass of air in the combustion chamber. The fuel is injected during the intake stroke. This mode activates at high load conditions and provides maximum output and torque.

Direct injection can also be accompanied by traditional methods such as VVT and VLIM, which provide conventional control over airflow swirl patterns at stoichiometric and full power modes. Water injection or EGR can help reduce NOx emissions inevitable when burning ultra lean mixtures.

Engine efficiency

Engine efficiency of thermal engines is the relationship between the total energy contained in the fuel, and the amount of energy used to perform useful work. There are two classifications of thermal engines-
(1) Internal combustion (gasoline, Diesel and gas turbine, ie., Brayton cycle engines).
(2) External combustion engines (Steam piston, steam turbine, and the Stirling cycle engine).

Each of these engines has thermal efficiency characterisics that are unique to it.

Modern gasoline motors, have an average efficiency of about 25% when used to power an automobile. In other words, of the total energy of gasoline, 75% is consumed by the motor itself and dissipated in the form of heat and only 25% of energy moves the vehicle. At idle and slow speed the efficiency is much lower than average and improves considerably at open road speeds. Diesel motors are more efficient. The most efficient type, direct injection Diesels, are able to reach an efficiency of about 40% in the engine speed range of idle to about 1,800 RPM. Beyond this speed, efficiency begins to decline due to air pumping losses within the engine.

The efficiency depends on several factors, one of them is the compression ratio; most gasoline engines, have a ratio of 10:1 or 8:1 with some high performance engines reaching a ratio of 12:1. The greater the ratio the more efficient is the machine. Higher ratio engines need fuel with higher octane value.

Diesel engines have a compression ratio between 14:1 to 25:1. In this case the general rule does not apply because Diesels with compression ratios over 20:1 are indirect injection Diesels which use a prechamber to make possible high RPM operation as is required in automobiles and light trucks. The thermal and gas dynamic losses from the prechamber result in direct injection Diesels despite their lower compression ratio being more efficient. An engine has many parts that produce friction and this friction increases at high RPM. A motor is more efficient at low RPM than at high RPM. The loss of efficency as RPM rise becomes proportionately greater due to air pumping losses which increase much faster than friction losses.

Piston steam engines are very inefficient which is why there are no longer any steam locomotives in commercial use. Large output steam turbines equal or exceed the efficiency of the Diesel, which is why they are used for electric utility generating plants. The Stirling engine has the highest efficiency of any thermal engine but it is very expensive to make and is not competitive with other types for normal commercial use.

The gas turbine is most efficient at maximum power output. Efficiency declines steadily with reduced power output and is very poor in the low power range. This is one reason, among several, why the gas turbine is not used for automobiles and trucks where much of the operating cycle is at idle and low to intermediate speeds. Detroit at one time tried to make a gas turbine for an automobile and gave up. This is also why gas turbines can be used for peak power electric plants. In this application they are only run at full power where they are efficient or shut down when not needed.

F-Head Engine

The term F-head engine specifies one valve arrangement for an internal combustion engine of the Otto cycle type. In this type of engine, the intake manifold and its valves are located atop the cylinders (in the cylinder head) and are operated by pushrods, but the exhaust manifold and its valves are located beside the cylinders (in the block). The exhaust valves are either roughly or exactly parallel with the pistons; their faces point upwards and they are not operated by pushrods, but by direct contact with a camshaft.

This was a more expensive engine design. Its advantages over the competitors of its day (T-head engines) included more power from its higher compression and better intake mixture flow; and greater reliability from its cooling of the exhaust valve and its spring and having half the number of pushrods of an OHV engine.

For years the British motor car firms Rolls-Royce and Rover used this arrangement. From 1927-1929, the American firm Hudson used a 6-cylinder engine of this form as well, but this engine is not to be confused with that of the race-winning Hudsons of the 1950s.

Willys and later Kaiser-Jeep made use of the Hurricane F-head design into the 1970s. This engine was the last F-head used in the U. S.

It was generally replaced by the overhead valve engine.

The term should not be confused with the Flathead engine.

Chrysler PowerTech engine

The PowerTech is a new engine family for DaimlerChrysler and is not based on the Chrysler A engine like almost every other Chrysler V8. A 4.7 L V8 came first for the Jeep Grand Cherokee, and a 3.7 L V6 version debuted in 2002 for the Jeep Liberty. The PowerTech V6 and V8 were direct replacements for Chrysler's LA family in the early 2000s.

Note that Chrysler uses the "PowerTech" name on a number of different engines:

* The older AMC Straight 6 engine (from 1996 onwards)
* The 2.4 L Neon engine for trucks

The PowerTech engines are produced at the Mack Avenue Engine Complex in Detroit, Michigan.



4.7

The 4.7 liter version was the first of this family, appearing in the 1999 Jeep Grand Cherokee. The displacement is 4.7 L (4701 cc/286 in³) with a bore of 3.66 in (93 mm) and a stroke of 3.40 in (86.4 mm). It has a cast iron block and aluminum "almost Hemi" heads with two valves per cylinder. It uses a chain-driven overhead camshaft. It produces 235 hp (175 kW) and 295 ft·lbf (400 N·m) of torque.

The PowerTech was on the Ward's 10 Best Engines list for 1999.

Applications:

* 1999-present Jeep Grand Cherokee
* 2000-present Dodge Dakota
* 2000-present Dodge Durango
* 2002-present Dodge Ram
* 2006-present Jeep Commander
* 2007-present Chrysler Aspen


4.7 HO

A "High-Output" version of the 4.7 L PowerTech engine, producing 260 hp (195 kW) and 330 ft·lbf (448 N·m) of torque, was introduced in 2002, first appearing in the Jeep Grand Cherokee Special Edition.

Applications:

* 2002-2004 Jeep Grand Cherokee available on Limited, Overland and Special Edition models
* 2005-present Dodge Dakota
* 2008 Dodge Challenger [base models]


3.7 EKG

The EKG is a 3.7 L (3701 cc) version built in Detroit, Michigan. Bore is 93 mm and stroke is 90.8 mm. It is a 90° V engine like the V8, with SOHC 2-valve heads. Output is 210 hp (160 kW) at 5200 rpm with 235 ft.lbf (319 Nm) of torque at 4000 rpm. It has a cast iron engine block and aluminum SOHC cylinder heads. It uses SFI fuel injection, has roller followers, and features fracture-split forged powder metal connecting rods and an assembled reinforced plastic intake manifold.

Applications:

* 2002-present Dodge Ram
* 2004-present Dodge Dakota
* 2004-present Dodge Durango
* 2007-present Dodge Nitro

* 2002-present Jeep Liberty
* 2005-present Jeep Grand Cherokee
* 2006-present Jeep Commander


Power curve for the 3.7L PowerTech V6 as implemented in the Dodge Nitro:

http://www.dodge.com/en/nitro/capability.html?feature=3_7_liter_v6


2.4

The 2.4 L I4 PowerTech is actually a Neon engine variant.

Ford Taunus V4 engine

The Taunus V4 was a V4 piston engine with one balance shaft, introduced by Ford Motor Company in Germany in 1962. The German V4 was built in the Cologne plant and powered the Ford Taunus and German versions of the Consul, Granada and Transit. It was not a 'true' V engine as two opposing pistons did not share one crankpin on the crankshaft.

The V4 was later expanded into the Ford Cologne V6 engine that is used in the Ford Capri and many other Ford cars. The V4 engine was (and still is) also used in industrial applications: pumps, electrical generators, and in agricultural machinery. In automobiles, the Taunus V4 was replaced by the Ford OHC/Pinto engine.

Applications:

* Ford Taunus
* Ford Consul
* Ford Granada
* Ford Transit
* Saab 95
* Saab 96
* Saab Sonett (II-V4 and III)
* Matra 530


1.2

The 1.2 L (1183 cm³) version features an 80.0 mm bore and 58.86 mm stroke. Output was 40 hp (29 kW) and 80 Nm or 45 hp (33 KW) and 82 Nm.

Applications:

* 1962 - 1966 Ford Taunus 12M P4
* 1967 - 1968 Ford Taunus 12M P6


1.3

The 1,3 L (1288 cm³) version had an 84,00 mm bore and 58,86 mm stroke. Output was 50 hp (37 KW) and 95 Nm or 53 hp (39 KW) and 98 Nm.

Applications:

* 1966 - 1970 Ford Taunus 12M P6
* 1969 - 1972 Ford Capri


1.5

The 1.5 L (1498 cm³) V4 had a 90.0 mm bore and 58.86 mm stroke. It produced 55 hp (40 kW) and 107 Nm, 60 hp (44 kW) and 114 Nm or 65 hp (48 kW) and 117 Nm at 2500 RPM.

Applications:

* 1962-1966 Ford Taunus 12M P4
* 1966-1970 Ford Taunus 15M P6
* 1964-1967 Ford Taunus 17M P5
* 1967-1971 Ford Taunus 17M P7
* 1969-1972 Ford Capri
* 1967-1980 Saab 95 and Saab 96 (European market)
* 1967-1970 Saab 95, Saab 96 and Saab Sonett (USA market)

Since it the Saab 96 was used for rallying it was also tuned. In the rally versions it was bored out to 1784 cm³ and 1933 cm³ giving aroud 150 hp in the naturally aspired version and 200 hp DIN at 7000 rpm in the Saab 96 RC Turbo version doing 0 to 100 km/h in five seconds. SAAB also tuned the engine to 240 hp.


1.7

The 1.7 L (1699 cm³) V4 had a 90.0 mm bore and 66.8 mm stroke. It produced 65 hp (48kW) and 129 Nm, 70 hp (52 kW) and 137 Nm or 75 hp (55 kW) and 130 Nm.

Applications:

* 1964-1967 Ford Taunus 17M P5
* 1967-1971 Ford Taunus 17M P7
* 1967-1972 Matra 530
* 1969-1972 Ford Capri
* 1972-1975 Ford Consul (German version)
* 1975-1981 Ford Granada (German version)
* 1971-1974 Saab 95, Saab 96 and Saab Sonett, low compression version with 65 hp for USA market


Also, some DKW Munga, a Jeep like vehicle used in the German army were retrofitted with this Ford V4, to replace its standard two stroke engine.

Since the engine mounts and gearbox connections are identical between the Ford Cologne V6 engine and the V4, some vintage V4 Saab 96s were modified to take a V6, for rally racing, although this dramatically changed the weight distribution and steering characteristics.

Saab two-stroke engine

The first Saab two-stroke engine was based on a DKW design. The SAAB engine, a two cylinder with 764 cm3 engine displacement and 25 hp was transversally placed in the 1950 - 1956 Saab 92, giving it a top speed of 100 km/h. With the 1954 model engine output was raised to 28 hp. It had some features only found in modern cars such as one ignition coil per cylinder.

The second type of SAAB two stroke engine was a longitudinally placed 3 cylinder of 748 cc and initially 33 hp. This engine was used in the Saabs 93, 94 (with an engine tuned to 57,5 hp), Saab Sonett I and II, 95, 96, Saab GT750, the Saab Formula Junior and the Saab Quantum.

The 1958-59 Sports version of the 93B had 48-50 hp in base version and 57 hp in super version. This model had triple carburetors.

From 1959 displacement was raised to 841 cc with 38 hp. For model year 1966, the 'standard' 3-cylinder two-stroke engine was fitted with triple carburetors. From model year 1967 it was replaced with the Ford Taunus V4 engine.

SAAB also made some experimental V6 engines, by mounting two three cylinder two-stroke engines together, at an angle. One had carburetors on the outside, while another was more conventional, with a carburetor in between the two blocks.

Toyota 2ZZ-GE engine

The 2ZZ-GE is a 1.8 L (1796 cc) version built in Japan. Bore is 82 mm and stroke is 85 mm. Output is 180 hp (134 kW) at 7600 RPM with 130 ft·lbf (176 N·m) of torque at 6800 RPM. It uses MFI fuel injection, has VVTL-i, and features forged steel connecting rods. Compression ratio is 11.5:1. Unlike others in the ZZ family, the 2ZZ-GE requires "premium" gasoline - 91 octane or above in the USA. Power output for this engine varies depending on the application and tuning, with the Lotus Elise and Lotus Exige offering 190 hp but the Pontiac Vibe, Toyota Corolla and Toyota Matrix versions only developing 180 hp (+2005: 170 hp). The Australian variant (Corolla Sportivo and Celica GTS) is 141kw@7600 and 181N·m Torque due to noise regulations. (Toyota recalled them for a flash of the ECU to up their output to put them into the more lenient "sports car" noise category). The Corolla Compressor and Lotus Exige S add a supercharger to achieve 225 hp, while the Exige 240R's supercharger increases output to 240 hp.

The 2ZZ-GE utilizes a dual camshaft profile system (the "L" in VVTL-i, known by enthusiasts as "lift"), to produce the added power without an increase in displacement or forced induction compared to the lesser engines in the ZZ series. This is similar in concept to Honda's i-VTEC, but the two systems are very different in design and execution.

Toyota commissioned Yamaha to design the 2ZZ-GE, and it shares several similarities with street bike engines, the most notable being the relatively high RPM design. The high-output cam profile is not activated until above 6000 RPM (the exact point of engagement is different depending on the vehicle, year, and ECU involved). On all of the Toyota-built vehicles, redline begins at 8200 RPM while the tachometer is typically numbered to 9000, giving an incredibly small "unusable" range. The Toyota ECU electronically limits RPM to about 8200 (through fuel and/or spark cut). It is impossible to "over-rev" the engine with the throttle alone; a downshift from a higher gear is required. But if you manage to do it, the oil pump commonly disintegrates the lobe ring.

The motor will happily run at ~4000 RPM for extended periods of time, and during stress testing the motor will run at the 8200RPM redline for extended periods without issue. For the first few years of production, the engines were notorious for breaking off the "lift bolts" inside the engine. This didn't do any damage, but did hamper performance, as the high output cam profile would not engage properly. Toyota fixed the problem in late 2002, and there is a TSB for dealers showing what bolt to replace and the redesigned bolt.

Applications:

* Toyota Celica SS-II (Japan, 190 PS)
* Toyota Celica GT-S (USA, 180 hp)
* Toyota Celica 190/T-Sport (UK, 189hp)
* Toyota Corolla Sportivo (Australia, 182 hp)
* Toyota Corolla TS (Europe, 192 PS)
* Toyota Corolla Compressor (Europe, 225 PS)
* Toyota Corolla XRS (USA, 164 hp)
* Toyota Corolla Fielder Z Aero Tourer (Japan, 190 PS)
* Toyota Corolla Runx Z Aero Tourer (Japan, 190 PS)
* Toyota Matrix XRS
* Pontiac Vibe GT
* Lotus Elise (North America/UK)
* Lotus Exige (US/UK)

Boost controller

Boost control is the principle of controlling the boost level produced in the intake manifold of a turbocharged or supercharged engine by affecting the air pressure delivered to the pneumatic and mechanical wastegate actuator. Boost controllers can be as simple as a manual boost controller which can be easily fabricated oneself. One may also be included as part of the engine management computer in a factory turbocharged car, or an aftermarket electronic boost controller such as those made by Apex-i or GReddy.


Principles of operation

Without any boost controller, air pressure is fed from the charge air (compressed side) of the turbocharger directly to the wastegate actuator via a vacuum hose. This air pressure can come from anywhere on the intake after the turbo, including after the throttle body, though that is less common. This air pressure pushes against the force of a spring located in the wastegate actuator to allow the wastegate to open and bypass exhaust gas from reaching the turbine wheel. In this simple configuration, the spring's springrate and preload determine how much boost pressure the system will achieve. Springs are classified by the boost pressure they typically achieve, such as a "7 psi spring" that will allow the turbocharger to reach equilibrium at approximately 7 psi.

One primary problem of this system is the wastegate will start to open well before the actual desired boost pressure is achieved. This negatively affects the threshold of boost onset and also increases turbocharger lag. For instance, a spring rated at 7 psi may allow the wastegate to begin to (but not fully) open at as little as 3.5 psi.

Achieving a moderate boost levels consistently is also troublesome with this configuration. At partial throttle, full boost may still be reached, making the vehicle difficult to control with precision. Electronic systems can allow the throttle to control the level of boost, so that only at full throttle will maximum boost levels be achieved and intermediate levels of boost can be held consistently at partial throttle levels.
compartment.


Manual boost control

A manual boost controller is a simple mechanical and pneumatic control to allow some pressure from the wastegate actuator to escape or bleed out to the atmosphere or back into the intake system. This can be as simple as a T-fitting on the boost control line near the actuator with a small bleeder screw. The screw can be turned out to varying degrees to allow air to bleed out of the system, relieving pressure on the wastegate actuator, thus increasing boost levels. These devices are popular due to their negligible cost compared to other devices that may offer the same power increase.

Generally a manual boost controller will not be accessible from inside the car, though some are designed to be. An installation that allows access from inside the car (as opposed from inside the engine compartment) is more complex, as the tubing must be longer and a hole must be drilled. It is possible and beneficial to use two manual boost controllers at different settings with a solenoid to switch between them for two different boost pressure settings. Some factory turbocharged cars have a switch to regulate boost pressure, such as a setting designed for fuel economy and a setting for performance.

Manual boost controllers do not solve partial throttle/full boost, drivability, and response or lag issues. They can be used in conjunction with some electronic systems.


Electronic boost control

Electronic boost control adds an air control solenoid and/or a stepper motor controlled by an electronic control unit. The same general principle of a manual controller is present, which is to control the air pressure presented to the wastegate actuator. Further control and intelligent algorithms can be introduced, refining and increasing control over actual boost pressure delivered to the engine.

At the component level, boost pressure can either be bled out of the control lines or blocked outright. Either can achieve the goal of reducing pressure pushing against the wastegate. In a bleed-type system air is allowed to pass out of the control lines, reducing the load on the wastegate actuator. On a blocking configuration, air traveling from the charge air supply to the wastegate actuator is blocked while simultaneously bleeding any pressure that has previously built up at the wastegate actuator.


Control details

Control for the solenoids and stepper motors can be either closed loop or open loop. Closed loop systems rely on feedback from a manifold pressure sensor to meet a predetermined boost pressure. Open loop systems have a predetermined control output where control output is merely based on other inputs such as throttle angle and/or engine RPM. Open loop specifically leaves out a desired boost level, while closed loop attempts to target a specific level of boost pressure. Since open loop systems do not modify control levels based on MAP sensor, differing boost pressure levels may be reached based on outside variables such as weather conditions or engine coolant temperature. For this reason, systems that do not feature closed loop operation are not as widespread.

Solenoids are driven by pulse-width modulation as they are binary state devices, either allowing air flow or blocking it between any two given ports. By modifying the pulse width at a sufficiently high frequency, average air pressure over time can be controlled. Solenoids may require small diameter restrictors be installed in the air control lines to limit airflow and even out the on/off nature of their operation.

Stepper motors allow fine control of airflow based on position and speed of the motor, but may have low total airflow capability. Some systems use a solenoid in conjunction with a stepper motor, with the stepper motor allowing fine control and the solenoid coarse control.

Many configurations are possible with 2-, 3-, and 4-port solenoids and stepper motors in series or parallel. Two port solenoid bleed systems with a PID controller tend to be common on factory turbocharged cars.


Advantages

Since less positive pressure can be present at the wastegate actuator as desired boost is approached the wastegate remains closer to a completely closed state. This keeps exhaust gas routed through the turbine and increases energy transferred to the wheels of the turbocharger. Once desired boost is reached, closed loop based systems react by allowing more air pressure to reach the wastegate actuator to stop the further increase in air pressure so desired boost levels are maintained. This reduces turbocharger lag and lowers boost threshold. Boost pressure builds faster when the throttle is depressed quickly and allows boost pressure to build at lower engine RPM than without such a system.

This also allows the use of a much softer spring in the actuator. For instance, a 7 psi spring together with a boost controller may still be able to achieve a maximum boost level of well over 15 psi. The electronic control unit can be programmed to control 7 psi at half throttle, 12 psi at 3/4 throttle, and 15 psi at full throttle, or whatever levels the programmer or designer of the control unit intends. This partial throttle control greatly increases driver control over the engine and vehicle.


Limitations and Disadvantages

Even with an electronic controller, actuator springs that are too soft can cause the wastegate to open before desired. Exhaust gas backpressure is still pushing against the wastegate valve itself. This backpressure can overcome the spring pressure without the aid of the actuator at all. Electronic control may still enable control of boost to over double gauge pressure of the the spring's rated pressure.

The solenoid and stepper motors also need to be installed in such a way to maximize the advantages of failure modes. For instance, if a solenoid is installed to control boost electronically, it should be installed such that if the solenoid fails in the most common failure mode (probably non-energized position) the boost control falls back to simple wastagate actuator boost levels. It is possible a solenoid or stepper motor could get stuck in a position that lets no boost pressure reach the wastegate, causing boost to quickly rise out of control.

The electronic systems, extra hoses, solenoids and soforth add complexity to the turbocharger system. This runs counter to the "keep it simple" principle as there are more things that can go wrong. It is worth noting that virtually all modern factory turbocharged cars, the same cars with long warranty periods, implement electronic boost control. Manufactures such as Subaru, Mitsubishi and Saab integrate electronic boost control in all turbo model cars.


Availability and Applications

Electronic boost control systems are available as aftermarket stand-alone systems such as the Apex-i AVCR, as a built-in feature of modern factory turbocharged vehicles such as the Subaru Impreza WRX and often as built-in features in full aftermarket stand-alone engine management systems such as the AEM EMS and Mega Squirt.


Dangers in use

Installing a boost controller in a vehicle that is already well tuned (such as a factory turbocharged car) may allow higher boost pressure than tolerable by the engine or turbocharger reducing life and reliability. Care should be taken to avoid exceeding the limits of any the engine systems components such as the engine block, fuel injectors, or engine management system. This is as true with boost control as it is with fuel and timing controls or any number of other engine system modifications.

In particular, users may find the extremely low cost and ease of adding a manual boost controller a particular draw for extra power at low cost compared to more comprehensive modifications. Users should carefully consider how installing any boost controller may affect and interact with existing complex engine management systems. Additional boost levels may not be tolerated by the existing turbocharger, causing faster wear. Fuel injectors or the fuel pump may not be able to deliver additional fuel needed for higher air flow and power of higher boost pressure. Or the engine management system may not be able to properly compensate for fuel or ignition timing, causing knock and/or engine failure.


Past and Future

There are other outdated methods of boost control, such as intake restriction or bleed off. For instance, it is possible to install a large butterfly valve in the intake to restrict airflow as desired boost is approached. It is also possible to actually release large amounts of already compressed air similar to a blow-off valve but on a constant basis to maintain desired boost at the intake manifold. The currently popular exhaust gas bypass via wastegate is superior to creating intake restriction or wasting energy by releasing air that has already been compressed. These methods are rarely used in modern system due to the large sacrifices in efficiency, heat, and reliability.

Other methods may come into widespread use in the future, such as variable geometry turbochargers. With a sufficiently large turbine, no wastegate is necessary. Low speed response and faster spool up are then obtained using variable turbine technologies rather than a smaller turbine. These systems may replace or supplement typical wastegates as they develop. Control methods for the variable mechanical controls, such as the principles of closed loop will still apply even if they no longer involve pneumatics.

Programmable ECUs

A special category of ECUs are those which are programmable. These units do not have a fixed behavior, but can be reprogrammed by the user.

Programmable ECUs are required where significant aftermarket modifications have been made to a vehicles engine. Examples include, adding or changing of turbocharger, adding or changing of intercooler, changing of exhaust system, conversion to run on alternative fuel. As a consequence of these changes, the old ECU may not provide appropriate control for the new configuration.

In these situations, a programmable ECU can be wired in. These can be programmed/mapped while the engine is running by connecting a laptop to it using a serial or USB cable.

For example the programmable ECU may control the amount of fuel to be injected into each cylinder. This varies depending on the engine's RPM and the position of the gas pedal (or the manifold air pressure). The engine tuner can adjust this by bringing up a spreadsheet-like page on the laptop where each cell represents an intersection between a specific RPM value and a gas pedal position (or the throttle position, as it is called). In this cell a number corresponding to the amount of fuel to be injected is entered.

By modifying these values while monitoring the exhausts using a wide band lambda probe to see if the engine runs rich or lean, the tuner can find the optimal amount of fuel to inject to the engine at every different combination of RPM and throttle position. This process is often carried out at a dynamometer, giving the tuner a controlled environment to work in.

Other parameters that are often mappable are:

* Ignition : Defines when the spark plug should fire for a cylinder

* Rev limit : Defines the max RPM that the engine is allowed to rev to. After this fuel and/or ignition is cut.

* Water temperature correction : Allows for additional fuel to be added when the engine is cold (choke).

* Transient fueling : Tells the ECU to add a specific amount of fuel when throttle is applied.

* Low fuel pressure modifier : Tells the ECU to increase the injector fire time to compensate for a loss of fuel pressure.

* Closed loop lambda : Lets the ECU monitor a permanently installed lambda probe and modify the fueling to achieve stoichiometric (ideal) combustion.

Some of the more advanced race ECUs include functionality such as launch control, limiting the power of the engine in first gear to avoid burnouts. Other examples of advanced functions are:

* Waste gate control : Sets up the behavior of a turbo waste gate, controlling boost.

* Banked injection : Sets up the behavior of double injectors per cylinder, used to get a finer fuel injection control and atomization over a wide RPM range.

* Variable cam timing : Tells the CPU how to control variable intake and exhaust cams.

* Gear control : Tells the ECU to cut ignition during (sequential gearbox) upshifts or blip the throttle during downshifts.

A race ECU is often equipped with a data logger recording all sensors for later analysis using special software in a PC. This can be useful to track down engine stalls, misfires or other undesired behaviors during a race by downloading the log data and looking for anomalies after the event. The data logger usually has a capacity between 0.5 and 16 Mbytes.

In order to communicate with the driver, a race ECU can often be connected to a "data stack", which is a simple dash board presenting the driver with the current RPM, speed and other basic engine data. These race stacks, which are almost always digital, talk to the ECU using one of several proprietary protocols running over RS232, CANbus or ethernet.

Engine Control Unit

An Engine Control Unit (ECU) also known as an Engine Control Module (ECM) or Powertrain Control Unit/Module (PCU, PCM) if it controls both an engine and a transmission, is an electronic control unit which controls various aspects of an internal combustion engine's operation. The most simple ECUs simply control the quantity of fuel injected into each cylinder each engine cycle. More advanced ECUs found on most modern cars also control the ignition timing, Variable Cam Timing (VCT), the level of boost maintained by the turbocharger (in turbocharged cars), and control other peripherals.

ECUs determine the quantity of fuel, ignition timing and other parameters by monitoring the engine through sensors. These can include, MAP sensor, throttle position sensor, air temperature sensor, engine coolant temperature sensor and many others.

Before ECUs most engine parameters were fixed. The quantity of fuel per cylinder per engine cycle was determined by a Carburetor.



ECU Operation


Control of Fuel Injection

For an engine with fuel injection, an ECU will determine the quantity of fuel to inject based on a number of parameters. If the throttle pedal is pressed further down, the ECU will inject more fuel. If the engine has not warmed up yet, more fuel will be injected (causing the engine to run slightly 'rich' until the engine warms up).


Control of Ignition Timing

A spark ignition engine requires a spark to initiate combustion in the combustion chamber. An ECU can adjust the exact timing of the spark (called ignition timing) to provide better power and economy. If the ECU detects knock, a condition which is potentially destructive to engines, it can delay (retard) the timing of the spark to prevent this.


Control of Variable Cam Timing

Some engines have Variable Cam Timing. In such an engine, the ECU controls the time in the engine cycle at which the valves open. The valves are usually opened later at higher speed than at lower speed. This can optimise the flow of air into the cylinder, increasing power and economy.

AMC Computerized Engine Control

The Computerized Engine Control or CEC system was an engine management system designed and used by American Motors and Jeep from 1980-1990, on the AMC 258 engine.

CEC was unique in that almost all of its sensors and actuators were digital; instead of the usual analog throttle position, coolant temperature, intake temperature and manifold pressure sensors, it used a set of fixed pressure- and temperature-controlled switches (as well as a wide-open throttle switch on the carburetor) to control fuel mixture and ignition timing. The only analog sensor in the system was the oxygen sensor. In other respects, it was a typical feedback carburetor system of the early 1980s, using a stepper motor to control fuel mixture and a two-stage "Sole-Vac" (which used a solenoid for one stage, and a vacuum motor for the other) to control idle speed. CEC also controlled ignition timing using information from the fuel-control section and an engine knock sensor on the intake manifold.

The CEC module itself (the most common version of which is the "AMC MCU Super-D") was built for AMC by Ford Motor Company, and worked with a Ford Duraspark ignition system. Despite being built by Ford, the CEC module is not related to the Ford EEC systems internally.

Because of the many vacuum-driven components and electrical connections in the system, CEC-equipped engines have a reputation of being hard to tune. The 49-state model of the CEC has no on-board diagnostic system, making it difficult to monitor the computer's operation without a breakout box, and the Carter BBD carburetor on most CEC-equipped models has problems with its idle circuit clogging, causing rough idle and stalling. In places where emissions testing isn't required, a popular modification is to bypass the computer and replace the BBD with a manually-tuned carburetor; also, several vendors (including Chrysler) offer retrofit kits that replace the CEC and the carburetor with fuel injection.

4-stroke power valve system

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)


EXUP

EXUP (EXhaust Ultimate Power valve) is a device fitted to selected Yamaha motorcycles (FZR,YZF,R series) that constantly adjusts the internal diameter of the exhaust system to suit engine revs. This ensures good low to mid-range performance for a linear power output all the way to the rev limiter. This is achieved by using an internal valve inside the exhaust at the point where the four pipes from the cylinders meet. Due to the high performance of these particular engines at high RPM, the exhaust valve inside the piston tends to open early. This is beneficial to the performance of the engine at high RPM, but detrimental to performance at low RPM. Closing of the valve then creates back pressure inside the exhaust system, forcing down the piston. A servo motor controlled by the Ignitor module opens and shuts the valve. The EXUP valve operation goes from being fully closed at idle speed, through to being fully open at 9000 to 11000 RPM.


HTEV

HTEV (Honda Titanium Exhaust Valve) is a device fitted to Honda engines that constantly adjusts the internal diameter of the exhaust system to suit engine revs. This ensures good low to mid-range performance for a linear power output all the way to the rev limiter.

front-engine, rear wheel drive

Front-engine, rear wheel drive means a layout where the engine is in the front of the vehicle and drive wheels at the rear. This was the traditional automobile layout for most of the 20th century.


Overview

This layout is typically chosen for its simple design and weight distribution. Placing the engine at the front gives the vehicle a traditional long bonnet (in American dialect "hood") and engine cooling is simple to arrange. Placing the drive wheels at the rear allows ample room for the transmission in the center of the vehicle and avoids the mechanical problems of transmitting drive to steered wheels. The layout is still more suitable than front-wheel drive for engine outputs of more than about 200 bhp, as the weight transference during acceleration loads the rear wheels and increases grip.

The FM layout is based on the FR layout.


History

The first FR car was an 1895 Panhard model, so this layout was known as the "Système Panhard" in the early years. Most American cars used the FR layout until the mid 1980s. The Oil crisis of the 1970s and the success of small FF cars like the Mini, Volkswagen Rabbit, and Honda Civic led to the widespread adoption of that layout.

Some manufacturers, such as Alfa Romeo, Porsche (944,924,928) and Chevrolet (C5 and C6 Corvettes), retained this layout but moved the gearbox from behind the engine to between the rear wheels, putting more weight over the driven axle. This configuration is often referred to as a transaxle since the transmission and axle are one unit.

Right after the Arab Oil Embargo of 1973 and the 1979 fuel crises, a majority of American FR vehicles (station wagons, luxury sedans) were being phased out for the FF layout - this trend would spawn the SUV/van conversion market. Chrysler went 100% FF by 1990; only GM and Ford retained FR for their luxury and performance vehicles.

GM phased out its FR luxury cars after the 1996 model year, and its F-car (Chevrolet Camaro/Pontiac Firebird) in 2002. GM reintroduced North American FR luxury cars with the 2003 Cadillac CTS. Currently they produce the Pontiac GTO (imported from Australia), Chevrolet Corvette/Cadillac XLR and the Cadillac CTS/STS. GM Holden continued to produce RWD cars through this period.

Today, most cars are FF, though the limitations of that layout, such as poor traction under acceleration and excessive nose weight, are beginning to become apparent. Many of the newest models have adopted all wheel drive, and some, like the Chrysler 300 are switching back to the FR layout. Most sports cars and luxury cars have always been FR.

Continuously variable transmission

The continuously variable transmission (CVT) is a transmission in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of a vehicle or other machine, can be varied continuously within a given range, providing an infinite number of possible ratios.

The continuously variable transmission should not be confused with the power split transmission (PST), as used in the Toyota Prius and other hybrid vehicles that use two or more inputs with one output, despite some similarities in their function.

A CVT need not be automatic, nor include zero or reverse output. Such features may be adapted to CVTs in certain specific applications.

Other mechanical transmissions only allow a few different discrete gear ratios to be selected, but the continuously variable transmission essentially has an infinite number of ratios available within a finite range, so it enables the relationship between the speed of a vehicle engine and the driven speed of the wheels to be selected within a continuous range. This can provide better fuel economy than other transmissions by enabling the engine to run at its most efficient speeds within a narrow range.

CVT transmissions have been refined over the years and are much improved from their origins.



Types


Infinitely Variable Transmission (IVT)

A specific type of CVT is the infinitely variable transmission (IVT), which has an infinite range of input/output ratios in addition to its infinite number of possible ratios; this qualification for the IVT implies that its range of ratios includes a zero output/input ratio that can be continuously approached from a defined "higher" ratio. A zero output implies an infinite input, which can be continuously approached from a given finite input value with an IVT. Low gears are a reference to low ratios of output/input which have high input/output ratios that are taken to the extreme with IVTs, resulting in a "neutral", or non-driving "low" gear limit. Most continuously variable transmissions are not infinitely variable.

Most (if not all) IVTs result from the combination of a CVT with an epicyclic gear system (which is also known as a planetary gear system) that facilitates the subtraction of one speed from another speed within the set of input and planetary gear rotations. This subtraction only needs to result in an continuous range of values that includes a zero output; the maximum output/input ratio can be arbitrarily chosen from infinite practical possibilities through selection of extraneous input or output gear, pulley or sprocket sizes without affecting the zero output or the continuity of the whole system. Importantly, the IVT is distinguished as being "infinite" in its ratio of high gear to low gear within its range; high gear is infinite times higher than low gear. The IVT is always engaged, even during its zero output adjustment.

The term "Infinitely Variable Transmission" does not imply reverse direction, disengagement, automatic operation, or any other quality except ratio selectabilty within a continuous range of input/output ratios from a defined minimum to an undefined, "infinite" maximum. This means continuous range from a defined output/input to zero output/input ratio.


Ratcheting CVT

The Ratcheting CVT is a transmission that relies on static friction and is based on a set of elements that successively become engaged and then disengaged between the driving system and the driven system, often using oscillating or indexing motion in conjunction with one-way clutches or ratchets that rectify and sum only "forward" motion. The transmission ratio is adjusted by changing linkage geometry within the oscillating elements, so that the summed maximum linkage speed is adjusted, even when the average linkage speed remains constant. Power is transferred from input to output only when the clutch or ratchet is engaged, and therefore when its locked into a static friction mode where the driving & driven rotating surfaces momentarily rotate together without slippage.

These CVT transmissions can transfer substantial torque because their static friction actually increases relative to torque throughput, so slippage is impossible in properly designed systems. Efficiency is generally high because most of the dynamic friction is caused by very slight transitional clutch speed changes. The drawback to ratcheting CVT's is vibration caused by the successive transition in speed required to accelerate the element which must supplant the previously operating & decelerating, power transmitting element. An Infinitely Variable Transmission (IVT) that is based on a Ratcheting CVT and subtraction of one speed from another will greatly amplify the vibration as the IVT output/input ratio approaches zero.

Ratcheting CVT's are distinguished from Variable Diameter Pulleys (VDP's) and Roller-based CVT's by being static friction-based devices, as opposed to being dynamic friction-based devices that waste significant energy through slippage of twisting surfaces.


Variable-diameter pulley (VDP)

This type of CVT uses pulleys, typically connected by a rubber-covered metal or laminated steel belt. A chain may also be used. A large pulley connected to a smaller pulley with a belt or chain will operate in the same manner as a large gear meshing with a smaller gear. Typical CVTs have pulleys formed as pairs of opposing cones. Moving the cones in and out has the effect of changing the pulley diameter since the belt or chain must take a large-diameter path when the conical pulley halves are close together. This motion of the cones can be computer-controlled and driven, for example by a servo motor. However, in the light-weight VDP transmissions used in automatic motorscooters and light motorcycles