Car Glossary And Definitions
Unless you know a lot about cars, there may be a number of terms in auto language you don't understand, or abbreviations or acronyms that you are unsure of. Listed below are explanations of some of the words you may come across when you look at buying a new car.
4ECT-i - 4 Speed Electronically Controlled Automatic Transmission with intelligence.
The transmission computer networks with the engine computer to control hydraulic shift pressure more precisely. It also automatically adjusts for transmission wear over time.
4WD/AWD - 4 Wheel Drive/All Wheel Drive
Four-wheel drive, or 4x4 is a four-wheeled vehicle with a drivetrain that allows all four wheels to receive power from the engine simultaneously. This allows it more traction and better handling and makes it suitable for off-road purposes.
ABS - Anti-Lock Braking System
A computer controlled system on vehicles which prevents the wheels from locking while braking. When the brakes begin to lock, the computer pulses the brakes and allows each wheel to brake independently, which allows the driver to maintain control under heavy braking. It may also help to shorten braking distances by allowing the driver to hit the brake fully without skidding or loss of control.
ACC - Adaptive Cruise Control
This may also be known as Autonomous Cruise Control, Active Cruise Control or Intelligent Cruise Control (ICC). These systems use either a radar or laser setup to slow the car when it determines it is too close to the vehicle in front. It then accelerates back to the preset speed once it has judged it is again safe enough.
ACIS - Acoustic Control Induction System
This device allows a higher speed of air intake into the car's engine, optimizing the performance.
ADD - Automatic Disconnecting Differential System
This technology disconnects the front axles and hub assemblies from the drive shaft at the differential when the vehicle is in 2-wheel drive mode, and engages the front axles back to the differential when 4-wheel drive is selected by the driver. This makes it unnecessary to get out of the vehicle to disconnect them manually.
This is the level of wind resistance that a car has. It is typically measured in Cd units, which means coefficient of drag. The lower this number is, the more aerodynamic the vehicle is.
AFC - Air Fuel Controller
A device which determines the ratio of air to fuel being delivered to the engine.
ALR - Automatic Locking Retractor
A seatbelt that automatically adjusts to fit around a person or object. It also locks when it is pulled at high speed. This is a useful safety feature of most modern cars.
An alternator converts mechanical energy into electrical energy to operate the electrical systems in the car, such as electric windows, ignition, or other accessories. It also charges the battery when required.
Often a feature in off-road vehicles, the Approach Angle indicates what the steepest angle is that a vehicle can approach and drive up without damaging the body or chassis.
These are the handles placed on the inside of a vehicle to allow passenger leverage into and out of a car.
AS - Active Steer
Active steering is a system that varies the degree that the wheels turn in response to the steering wheel. At lower speeds, this technology reduces the amount that the steering wheel must be turned, improving vehicle performance in situations such as parking. At higher speeds, the performance is such that steering becomes more responsive and provides improved directional stability.
Automatic Height Control
A hydraulic system that allows a driver to raise or lower the vehicle according to the requirements of the terrain. This is useful in off-road conditions.
Auto On/Auto Off Headlights
A system which evaluates the amount of daylight and automatically turns the headlights on or off as required.
The axle is the shaft on which a wheel turns. It can provide torque to the drive wheels.
A device which converts chemical energy into electrical energy. The battery provides the power used in a vehicle's electrical system and ignition.
BHP - Brake Horsepower
This is the measure of an engine's horsepower and is taken from the back of the engine before it loses power through the gearbox, generator, differential, water pump, and other auxiliary components.
The outward or inward tilt of a vehicle's tire. A tire tilted outward has a positive camber; a tire tilted inwards has a negative camber.
CAT - Catalytic Converter
A device incorporated into the exhaust system of a vehicle that reduces the amount of pollution in the automobile's exhaust. The downside to this is that it takes some of the performance away from the vehicle.
CATS - Computer Active Technology System
Computer Active Technology Systems allow control of the vehicle's body movements and helps to eliminate body roll in situations such as cornering, accelerating, and braking. This is made possible through an on-board computer which detects body movement from sensors located throughout the vehicle, and controls the action of the active suspension. Sensors continually monitor body movement and vehicle level and supply the computer with updated data constantly.
CBC - Cornering Brake Control
CBC works together with Anti-lock Braking Systems (ABS) to negate over-steer when going around corners at speed. CBC allows optimum distribution of brake power in corners, keeping the car on track even if the brakes are applied suddenly when cornering. This results in significantly safer and gentler braking. Even during abrupt braking, the vehicle remains stable.
CBV - Compressor Bypass Valve
A Compressor Bypass Valve may also be known as a Compressor Relief Valve (CRV). It is a vacuum-actuated valve which releases pressure in the intake system of a turbocharged or centrifugally supercharged car when the accelerator is lifted. The air pressure is re-circulated back into the non-pressurized end of the intake, before the turbo, but after the mass airflow sensor.
cc - cubic centimeters
CE - Classic Edition
The chassis of a vehicle is the frame with all the operating parts, such as the engine, the drivetrain, suspension and brakes. It does not include the body of the car - trim and accessories.
ci - cubic inches
The cubic inch was used until the 1980s to demonstrate the size of engines for vehicles. It is sometimes still used when talking about Classic Cars or auto racing, but has generally been replaced by SI.
The clutch connects the transmission to the drivetrain.
The place where burning of the air/fuel combination occurs. This is located on top of the cylinders.
Measure how much the air/fuel combination is compressed within the cylinder by the piston. Higher compression ratios give greater power.
CVT - Continuously Variable Transmission
A Continuously Variable Transmission is a gearbox in which the ratio of the rotational speeds of two shafts, as the input shaft and output shaft of your car can be varied continuously within a given range, providing an infinite number of possible ratios. This allows for a seamless transition between gears, ensuring a smooth ride.
A hollow tube in the engine block which contains a piston.
DAC - Downhill Assist Control
Sometimes when going down a particularly steep hill, use of low gear may not be enough to ensure a low speed. DAC automatically applies the brakes to lower the speed without the wheels locking up.
DBC - Dynamic Brake Control
Dynamic Brake Control is a safety feature which improves brake effectiveness in emergency stop situations. When you need to stop in an emergency, the system reinforces your applying the brakes to provide maximum braking in the shortest distance. The amount of brake application is determined by the speed and pressure with which you apply the brakes.
DE - Deluxe Edition
The differential is a gear assembly that enables a wheel of a vehicle to be turned at different speeds to the other wheels. This is a necessary component of a vehicle as when turning a corner, the wheel on the outside of the corner must turn more than the wheel on the inside of the corner.
A mechanical part of an ignition system that distributes electric power to the spark plugs. In new vehicles, this has been replaced by the distributorless ignition.
This system uses an ignition coil on top of each spark plug to time spark plug firing, eliminating the need for a distributor.
DOHC - Double/Dual Overhead CamShaft
A Dual or Double Overhead Camshaft (may also be known as a Twin-Camshaft) is an engine layout with two camshafts per row of cylinders. Each camshaft operates two valves, and a DOHC enables the car to have four valves per cylinder. Valves work by allowing the intake of air to the engine and providing an outlet for the exhaust. The engine can make more power if more air enters the cylinder, and it wastes less power if it is easier to pump the exhaust. A Dual Overhead Camshaft gives the vehicle higher performance - the engine will run at a higher speed and produce more power.
Shows the location of the engine within the vehicle, and which wheels power the car.
The shaft which carries power from the transmission to the differential.
The Drivetrain takes the engine output and transfers it to the wheels to produce motion. It is composed of the transmission, the driveshaft, the differential and the axle.
DRL - Daytime Running Lights
Runs the low-beam headlights during the day to increase the visibility of the vehicle to others.
DSC - Dynamic Stability Control
This system continually compares vehicle speed, wheel speed, steering angle, and yaw rate with a standard of optimum driving conditions data. This system can instantly recognize a threatening instability and a danger of skidding. The DSC system can correct an unstable driving condition by applying precise braking action to the individual wheels. This technology will also cut back the engine speed to stabilize the vehicle if it determines this is necessary.
DSG - Direct Shift Gearbox
The Direct Shift Gearbox is a dual-clutch gearbox. By using two clutches, fast shifts can be achieved, and the torque converter of a regular automatic transmission is eliminated.
DSR - Dynamic Steering Response
Dynamic Steering Response is a safety technique which corrects the rate of hydraulic or electric power steering system to adapt it to a vehicle's speed and road conditions.
DVC - Dynamic Vehicle Control
This function is comprised of a series of innovations and devices designed to create optimal driving performance to a tilting vehicle. This is possible through a feedback controlled tilting system enabling the vehicle to lean into corners always keeping it in perfect balance.
EBA - Electronic Brake Assist
Often partnered with EBD, this system monitors a driver's braking and if it detects that a driver is in an emergency braking manoeuvre, it automatically supplements the driver's attempt to stop quickly by boosting brake power to the maximum. This helps improve the vehicle's stopping distance. EBA stops working immediately after the driver releases the brake pedal.
EBD - Electronic Brake-force Distribution
Electronic Brakeforce Distribution is a brake technology that automatically varies the amount of force applied to each of a vehicle's brakes, based on road conditions, speed, loading, etc. This is often used in conjunction with anti-lock braking systems and can apply more or less braking pressure to each wheel in order to maximize stopping power. This results in more precise and effective braking and also makes the car more stable under heavy braking.
ECT - Electronically Controlled Transmission
Electronically controlled transmission is an advanced technology that through a hydraulic and electronic solenoid system enables more sophisticated control schemes. In addition to monitoring vehicle speed and accelerator position, the transmission controller can monitor the engine speed, if the brake pedal is being pressed, and even the anti-lock braking system. This results in automatic downshift when going downhill to control speed and reduce wear on the brakes, and upshift when braking on a slippery surface to reduce the braking torque applied by the engine.
ECU - Electronic/Engine Control Unit
This may also be known as an Engine Control Module (ECM) or Powertrain Control Unit/Module (PCU, PCM). It is an electronic unit which controls both an engine and a transmission. They come in differing levels of complexity. Some simply control the quantity of fuel injected into each cylinder each engine cycle. More advanced units found in most modern cars also control the ignition timing, variable valve timing, and the level of boost maintained by the turbocharger (in turbocharged cars).
EPS - Electronic Power Steering
An electronic motor which helps to reduce driver effort when steering. Most EPS systems also have Variable Assist to provide more assistance as the vehicle slows and less assistance in a high speed situation.
ESC - Electronic Stability Control
Electronic Stability Control is a system designed to improve a vehicle's handling, particularly at the limits where the driver might lose control of the vehicle.
ESP - Electronic Stability Program
The Electronic Stability Program further enhances the Anti-lock Braking System (ABS) and Traction Control System (TCS). It is designed to detect a difference between the driver's control inputs and the actual response of the vehicle. When the information differs, the system intervenes by providing braking forces to the necessary wheels to correct the vehicle. This automatic reaction improves vehicle stability, especially during harsh cornering and on low-friction road surfaces and reduces reduce over-steer and under-steer.
ETCS-i - Electronic Throttle Control System with intelligence
ETCS-i is used on all modern racing cars and is sometimes called drive-by-wire. When the accelerator is depressed, the engine immediately receives an electronic signal demanding more power. By replacing the more traditional but less efficient cable link between pedal and engine, ETCS-i can provide better fuel economy, faster responses and smoother acceleration.
These valves control the flow of the burnt air/fuel combination from the engine out into the atmosphere.
FF - Front Engine, Front Wheel Drive
Front-wheel drive is the most common form of engine and transmission layout used in modern cars. This involves the engine driving the front wheels. It allows for more passenger or cargo room, as opposed to rear-wheel drive which traditionally was the norm.
FI - Fuel Injected
This is a term used to describe injectors that squirt fuel under high pressure into the carburetor as a vapor. This makes the vehicle more economical to run and gives better performance. In modern cars, this technology is electronic and allows for precise measurement of the amount of fuel used, improving drivability, performance, economy and emissions control and is known as EFI (Electronic Fuel Injection).
FPR - Fuel Pressure Regulator
The Fuel Pressure Regulator is a simple device that keeps the pressure in the fuel system to a constant 28 psi and also reduces emissions during deceleration.
FR - Front engine, Rear wheel drive
An FR describes a car layout where the engine resides in the front of the vehicle and drive wheels at the rear. This configuration has been used up until quite recently. It typically has a more simple design and weight distribution. The engine in the front gives the vehicle a long hood, and engine cooling is simple to arrange. Having the drive wheels at the rear allows room for the transmission in the center of the vehicle. The layout is still often used for engine outputs of more than about 200 bhp, as the weight transference during acceleration loads the rear wheels and increases grip.
Delivers the fuel from the fuel tank to the fuel injectors.
GDI - Gasoline Direct Injection
Gasoline Direct Injection is a type of fuel injection used in four-stroke engines. The gasoline is highly pressurized and injected directly into the combustion chamber of each cylinder by a single-piston injection pump and common rail fuel line. GDI enables ultra lean burn to improve fuel efficiency and emission levels, and allows high power output.
GPS - Global Positioning System
A navigation system to help determine a vehicles' position in relation to other points via satellite. This system can also suggest appropriate routes to take to get you to a destination.
HAC - Hill-Start Assist Control
Helps increase control on an uphill gradient, particularly when stopping and starting. This system helps counter the backward slipping by gently applying the brakes to all four wheels while the driver depresses the accelerator.
An engine performance rating based on the working ability of an engine. The higher the unit of horsepower, the more power an engine has.
I(as in I-4) - Inline Cylinders
An internal combustion engine with cylinders aligned in a single row.
Delivers air and fuel to the engine's cylinders.
Valves through which air and fuel are delivered to the combustion chamber.
LDWS - Lane Departure Warning System
This is a safety device which uses warning sensors to alert drivers when the car is beginning to move out of its lane.
LSD - Limited Slip Differential
This helps to improve traction by distributing torque equally and preventing one wheel from spinning or slipping. This is a useful function to have in such situations as encountered on gravel, snow or when cornering. It is used in place of a standard differential, which is a more simple mechanism.
MAF/MAS - Mass Airflow Sensor
A mass flow sensor responds to the amount of a fluid flowing through a chamber containing the sensor. It is intended to be insensitive to the density of the fluid.
MR - Mid engine, Rear wheel drive
This is a layout in which the rear wheels are driven by an engine placed just in front of them, behind the passenger compartment in the middle of the car. The center of mass of the engine is in front of the rear axle. This layout is utilized for its favorable weight distribution, but is only practical for use in a two-seater sports car. It has a tendency toward being heavier in the rear than the front, which allows for optimum balance to be achieved under acceleration.
Using multiple valves to increase the flow of air/fuel mixture to the engine and exhaust gases out of the engine.
N/A - Naturally Aspirated
An engine that is not either turbo or super charged. Naturally aspirated engines usually give less power, but are significantly cheaper to produce and have better fuel efficiency.
Measures the distance a vehicle has driven.
This enables the transmission's driveshaft to operate at a higher speed than the engine. It reduces engine wear and noise and enables greater fuel efficiency.
A computer technology that through the use of sensors is able to detect and alert the driver to obstacles directly in the path of the vehicle.
The engine, transmission and final drive of a vehicle.
R - Racing or Rally version
The system that discharges heat from the liquid coolant in an engine into the atmosphere.
RAHC - Rear Adjustable Height Control
Rear Adjustable Height Control (RAHC) - hydraulically raises the rear of the vehicle by 1.6 inches and lowers it by 0.8 inches for easier loading and unloading.
Rear Adjustable Height Control (RAHC) - hydraulically raises the rear of the vehicle by 1.6 inches and lowers it by 0.8 inches for easier loading and unloading.
Rear Adjustable Height Control (RAHC) - hydraulically raises the rear of the vehicle by 1.6 inches and lowers it by 0.8 inches for easier loading and unloading. Hydraulically lowers or raises the back of the vehicle for easier loading and unloading.
RR - Rear engine, Rear wheel drive
An RR layout places both the engine and drive wheels at the rear of the vehicle. The center of gravity of the engine itself is actually past the rear axle. This layout is used mainly in super cars, as it improves overall handling and is suitable for high performance driving as the power goes straight directly to the wheels as opposed to through a drive train.
RWHP - Rear-Wheel Horsepower
S/C - Supercharged
A supercharger works in a similar way to a turbocharger. They are both forced induction systems, meaning they both work by compressing the air flowing into an engine. However, whilst a turbocharger gets power by using exhaust fumes, a supercharger uses a belt which is connected directly to an engine.
SE - Special Edition
SMG - Sequential Manual Gearbox
A Sequential Manual Gearbox (or transmission) is a type of manual transmission used in high-performance cars or auto racing, where gears are selected in order, and random access to specific gears is impossible.With a traditional manual gearbox, the driver can choose to move from any gear, to any gear. A clutch pedal must be depressed before the new gear is selected, to disengage the running engine from the transmission. In auto racing or high performance driving, this process is inefficient and can be eliminated through us of an SMG.
SOHC - Single Overhead Camshaft
Single overhead camshaft is a design in which one camshaft is placed within the cylinder head. In an in-line engine this means there is one camshaft in the head, while in a V engine there are two camshafts: one per cylinder bank.
SRS - Supplemental Restraint Systems
Also known as an airbag, a bag that is designed to inflate with air upon collision to help diffuse the impact and protect the occupants.
SUV - Sport Utility Vehicle
A sport utility vehicle, or SUV, is a passenger vehicle which combines the towing capacity of a pickup truck with the passenger-carrying space of a minivan or station wagon together with off road ability.
A device that ensures that the gears are rotating at the same speed before they are engaged in a gear change. This helps to eliminate grind or graunch.
T/C - Turbocharged
A turbocharger is a device in your cars engine which gives it an additional power boost. It works by using a turbine powered by exhaust gas from the engine. The rotation of the turbine drives the compressor, compressing ambient air and delivering it to the air intake of the engine. More air is accommodated in the engine, which in turn allows more fuel to be added, increasing the size of the explosion in each cylinder, and thus a bigger surge of power.Turbocharged vehicles do not have good fuel economy in general, as they consume more fuel in order to give a power surge. An average boost is around 6 - 8 pounds per square inch, which can equate to approximately 30 - 40% more power.
TCS - Traction Control System
An enhancement of an anti-lock braking system, traction control systems prevent wheel spin when accelerating on wet or slippery surface.
TDI - Turbocharged Direct Injection
This works through a turbocharger providing air to the engine, allowing optimum filling of the cylinder. After compression, injectors supply diesel to the engine at high pressure. This provides extra power that a diesel vehicle can often lack as a result of the fuel used.
TQ - Torque
Torque is a measure of how much a force acting on an object causes that object to rotate. It is the engine force that gets a vehicle to speed - felt especially at take-off and during acceleration.
V(as in V6) - V-Engine Type
An engine configuration in which the cylinders are laid out in a V formation.
VIN - Vehicle Identification Number
A unique 17 digit number on a vehicle which identifies it, and acts as a security measure against fraud. They are recorded on a database and all VINs are accessible by police and vehicle inspectors.
VIP - Vehicle Intrusion Protection
An alarm system to deter thieves from breaking into your car.
VSC - Vehicle Stability Control
The VSC system electronically monitors speed and direction, and compares the vehicle's direction of travel with the driver's steering, acceleration and braking inputs. VSC can help compensate for loss of traction which can cause skids.
VTEC - Valve Timing Electronic Control
This is a Honda technology. Other variations of this technology may be known as VVT-i, VVTL-i, MIVEC, VarioCam or VANOS depending on the car manufacturer.
In an engine, the best way to increase horsepower is to increase the engine's ability to process air. As valves have the role of introducing air into the combustion chamber and letting it back out into the exhaust system, manufacturers have advanced their technology to enable engine valves to open and close at different timings. A VTEC system works by using two sets of camshaft profiles. One is for low and mid-range rpm and one for high rpm operation. An electronic switch shifts between the two profiles at a specific rpm to increase peak horsepower and improve torque - useful in situations such as overtaking.
VVT-i - Variable Valve Timing with intelligence
A Toyota version of the VTEC system, this uses a hydraulic rather than mechanical system to alter the intake cam's phasing. However, this system only works on the intake valve instead of both the intake and the exhaust valves.
W(as in W16) - W-Engine Type
The W engine is an engine configuration in which the cylinder banks resemble the letter W.