The Engine Dictionary - AutoChoose.com
The Engine Dictionary - AutoChoose.com

The AutoChoose Engine Dictionary

Everything Engines from the simple Electric Motor to the Quad-Turbo W16

Cars are complicated. However it only takes learning a few terms to be better armed for the next time you walk into the dealer.

Select a category below to get started!

Gas Engines

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Commonly called an “internal combustion engine”, the gas engine produces power by burning a fuel such as gasoline, biogas (methane usually), or natural gas. Through a four-step process air is first drawn into the cylinder through the intake. The air is then compressed when the piston moves upward while fuel is also injected into the cylinder. The compressed fuel-air mixture is then ignited by the spark plugs creating an explosion that then powers the crankshaft and ultimately your tires.

Diesel Engines

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Although also considered an “internal combustion engine”, diesel engines can be differentiated from gas engines by the lack of spark plugs. Diesel is sprayed into the cylinder where it is mixed with air and compressed. However unlike gasoline the heat of compression ignites the diesel producing the power you need to move forward. Diesel is typically around 40% more efficient in terms of fuel economy but the trade off is diesel is typically much more expensive than gasoline in the United States.

Hybrids

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Hybrids are quickly becoming very popular in modern automobiles. A hybrid powertrain employs a standard gas or diesel engine partnered with an electric motor and a set of batteries. This electric motor feeds off the batteries to help propel the vehicle either during times when the engine is not needed such as during easy city driving or when some extra power is needed like when overtaking or accelerating onto a highway onramp. Many hybrids also feature a regenerative braking system that turns excess kinetic energy when coasting or braking into electricity to charge batteries.

Electric Powertrains

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Although is seems electric cars have only been with us for a few years, the first electric car was actually produced in the 1880’s. All electric vehicles are equipped with a large battery pack and at least one electric motor to power the wheels. All Electric vehicles also feature a regenerative braking system that turns excess kinetic energy when coasting or braking into electricity to charge batteries.

Hydrogen (Burning or Fuel Cell)

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Although not quite mainstream yet, hydrogen fuel cell vehicles are the future of automotive propulsion. Energy is created by one of two processes: burning hydrogen in a modified internal combustion engine or by reacting hydrogen with oxygen in a fuel cell to run electric motors. Hydrogen power has been used in buses for some time; you have to be living in certain areas of California if you want to be driving hydrogen-powered cars on the road.

Naturally Aspirated

A naturally aspirated engine is simply an engine that uses no form of outside force to increase the amount of air or fuel being sent into the cylinders. Many people favor this setup as naturally aspirated engines typically have a nicer and unmuffled exhaust note.

Turbocharging

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A turbocharger is a forced induction device that uses a turbine and compressor to force more air into the cylinders. The turbocharger’s turbine is powered by the engine’s exhaust gases that power the compressor condensing the intake air. Turbocharging can lead to huge gains in power and increased efficiency but also a softened exhaust note.

Supercharging

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A supercharger is a forced induction device that uses a mechanically driven compressor to force more air into the cylinders. The supercharger is typically run by a belt, gear, shaft, or chain. Supercharging produces gains in power and leaves the exhaust to sound natural however the supercharger itself saps some power from the engine.

Inline Configuration

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Also referred to as a “straight engine” an engine with an inline configuration has all cylinders aligned in a single row and has no offset. Usually found in three to six cylinder configurations, inline engines usually run smoother than typical “V-Configuration” engines however usually take up more space than a comparable “V-Configuration”. For example many vehicles that offer an inline-four cylinder option will also offer a V6 instead of an inline-six because a straight-six would be too large for the engine compartment.

Flat Configuration

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Sometimes called a “boxer” engine, a flat configuration is when the cylinders are in two different banks horizontally-opposed to one another. The most notable practice of this engine has been its use in the Porsche 911 for the past 50 years. Due to their inherently unbalanced nature, boxer engines tend to have a unique, mechanical exhaust note.

V-Configuration

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The most popular engine design besides inline, a “V-Configuration” engine has two banks of cylinders arranged in a “V” pattern allowing them to be compact and efficient. Depending on the number of cylinders used V-configuration engines tend to be better balanced than other engine designs, the V12 setup being the best example of this due to its marriage of two straight sixes.

W-Configuration

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Although not a widely common engine design, Volkswagen and it’s subsidiaries have put the W-engine to good use. Two V-shaped engines joined at the crankshaft form the “W” shape. The most common example of the W-engine is the W12 engine used the Audi A8 and multiple Bentley models however the most famous use is in the Bugatti Veyron hypercar with it’s use of two joined V8s and four turbochargers.

Rotary

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Also called a “Wankel” engine, the rotary engine is likely the motor configuration you are least likely to recognize. A single central piston spins with each stage in the cycle completing a different stage of combustion. The most notable use for a rotary was inside the Mazda RX-8 and its 9000-rpm redline. Rotary engines tend to have a very high power-to-weight ratio while running without any vibration. However, the single combustion chamber undergoing intake, compression, ignition, and exhaust phases at the same time leads to wear fairly quickly reducing efficiency and a greater need for oil.

Front-engine Setup

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Being the most frequent engine setup by miles, a front-engine setup is when the vehicle’s motor is placed in front of the driver under the hood. Usually placed on top of the front axle, some performance vehicles will have the engine positioned behind the front axle for better weight distribution. A front-engine setup will usually be mated with a front-wheel drive drivetrain giving a vehicle good traction in bad weather conditions. Unfortunately this setup is not idea for performance vehicles as the extra weight on the front axle also leads to push understeer in hard cornering.

Mid-engine Setup

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A mid-engine setup is usually seen in special performance vehicles. This engine placement is ideal for sports cars as having the engine’s weight between the front and rear axles results in a nearly perfect weight distribution and therefore better handling. The downsides of a mid-engine setup revolves primarily around cooling. Little airflow over then engine when stationary and the need for greater coolant plumbing can result in overheating and in some extreme cases engine fires. The need for extra engineering also accounts for higher manufacturing costs which is why many mid-engine vehicles are quite pricy.

Rear-engine Setup

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The rear-engine platform is commonly associated with one vehicle- the Porsche 911. For the past 50 years Porsche has stuck with this setup because with the engine’s weight hanging over the rear wheels, the rear wheels are pressed into the road resulting in better traction. The downsides of a rear-engine setup revolves primarily around cooling. Little airflow over then engine when stationary and the need for greater coolant plumbing can result in overheating and in some extreme cases engine fires. The need for extra engineering also accounts for higher manufacturing costs which is why many rear-engine vehicles are quite pricy.

Front-Wheel Drive (FWD)

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Front-wheel drive (FWD for short) is the most common type of drivetrain setup. In a FWD setup, power is sent from the engine to power the front wheels only. A vehicle with a FWD drivetrain is the most efficient system as having the engine close to the powered wheels reduces powertrain loss. Having the engine up front along with the front wheels being driven gives a vehicle better traction in bad weather conditions. Unfortunately this setup is not idea for performance vehicles as the extra weight on the front axle also leads to push understeer in hard cornering.

Rear-Wheel Drive (RWD)

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Rear-wheel (RWD for short) setups are commonly used on most luxury and sporting vehicles. By sending power to the rear wheels the front wheels are free to focus on steering only resulting in ideal handling characteristics. Another benefit to a RWD platform is through the balance of steering and throttle inputs the rear end of the vehicle can step out resulting in a “drift”. Although RWD is typically more fun, those fun characteristics can be a detriment when facing in poor weather conditions due to the rear end possibly stepping out accidentally.

All-Wheel Drive (AWD)

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All-wheel drive (AWD for short) drivetrains are commonly seen in SUVs and other off-roading vehicles. Also going by a number of generic names such as four-wheel drive and 4X4 along with multiple manufacturer-specific names (Audi Quattro, BMW xDrive, Mercedes 4Matic) all-wheel drive is simply when power from the engine can be sent to all four wheels. Most AWD vehicles also have the ability to distribute power between the forward and rear axles for better grip in low-traction conditions such as sand or snow. However, the need for extra engineering also accounts for higher manufacturing costs which is why many AWD vehicles are more expensive than their single axle rivals.