Automotive terms Modern (A)

Automotive Technical terms and abbreviations overview used in the vehicle industry, Guide and explanations.The following are examples of Mid to Modern technical terms recommended for general use worldwide. For in-depth specific terms also see terms for Historic, Vintage and specific areas such as Paint.

ABS:
Meaning Anti-lock braking system. An electro-mechanical braking system which is designed to minimize or prevent wheel lock-up during braking.

ABSOLUTE PRESSURE:
Meaning Atmospheric (barometric) pressure plus the Gauge reading.

ACCELERATOR
Normally foot-operated throttle also called gas pedal in the form of a pedal or lever, by which the flow of power fuel or electrify to the engine, motors is controlled.

ACCELERATOR PUMP:
Type A small pump located in the carburettor that feeds fuel into the air/fuel mixture during acceleration.

ACCUMULATOR:
Type A device that controls shift quality by cushioning the shock of hydraulic oil pressure being applied to a clutch or band.

ACTUATING MECHANISM:
The mechanical output devices of a hydraulic system, for example, clutch pistons and band servos.

ACTUATOR:
The output component of a hydraulic or electronic system.

ADVANCE:
Setting the ignition timing so that spark occurs earlier before the piston reaches top dead centre (TDC).

ADAPTIVE MEMORY (ADAPTIVE STRATEGY):
The learning ability of the TCM or PCM to redefine its decision-making process to provide optimum shift quality.

AFTER TOP DEAD CENTER (ATDC):
The point after the piston reaches the top of its travel on the compression stroke.

AIR BAG:
Device on the inside of the car designed to inflate on impact of crash, protecting the occupants of the car.

AIR BRAKE
A Modern aerodynamic performance spoiler designed to move at high-speeds or when braking quick often used on supercar vehicles.

AIR BRAKES
A compressed air type of brake used mainly in heavy in commercial vehicles.

AIR CHARGE TEMPERATURE (ACT) SENSOR:
The temperature of the airflow into the engine is measured by an ACT sensor, usually located in the lower intake manifold or air cleaner

AIR CLEANER:
An assembly consisting of a housing, filter and any connecting ductwork. The filter element is made up of a porous paper, sometimes with a wire mesh screening, and is designed to prevent airborne particles from entering the engine through the carburettor or throttle body.

AIR INJECTION:
One method of reducing harmful exhaust emissions by injecting air into each of the exhaust ports of an engine. The fresh air entering the hot exhaust manifold causes any remaining fuel to be burned before it can exit the tailpipe.

AIR PUMP:
An emission control device that supplies fresh air to the exhaust manifold to aid in more completely burning exhaust gases.

AIR/FUEL RATIO:
The ratio of air-to-gasoline by weight in the fuel mixture drawn into the engine.

ALDL (assembly line diagnostic link):
Electrical connector for scanning ECM/PCM/TCM input and output devices.

ALIGNMENT RACK:
A special drive-on vehicle lifts apparatus/measuring device used to adjust a vehicle's toe, caster and camber angles.

ALL WHEEL DRIVE (AWD):
All wheel drive. This system is found primarily on station wagon vehicles and SUVs not utilized for significant off-road use. Term used to describe a full-time four-wheel drive system or any other vehicle drive system that continuously delivers power to all four wheels.

ALTERNATIVE FUEL VEHICLE
Alternative to fossil fuel conventional engines such as electric or hydrogen powered.

ALTERNATING CURRENT (AC):
Electric current that flows first in one direction, then in the opposite direction, continually reversing flow.

ALTERNATOR:
A device which produces AC (alternating current) which is converted to DC (direct current) to charge the car battery.

AMMETER:
An instrument, calibrated in amperes, used to measure the flow of an electrical current in a circuit. Ammeters are always connected in series with the circuit being tested.

AMPERAGE:
The total amount of current (amperes) flowing in a circuit.

AMPLIFIER:
A device used in an electrical circuit to increase the voltage of an output signal.

AMP/HR. RATING (BATTERY):
Measurement of the ability of a battery to deliver a stated amount of current for a stated period of time. The
higher the amp/hc rating, the better the battery a must for large and Diesel engines auxiliary lighting and so on.

AMPERE:
The rate of flow of electrical current present when one volt of electrical pressure is applied against one ohm of electrical resistance.

ANALOG COMPUTER:
Any microprocessor that uses similar (analogous) electrical signals to make its calculations

ANODIZED:
A special coating applied to the surface of aluminium valves for extended service life.

ANTIFREEZE:
A substance (ethylene or propylene glycol) added to the coolant to prevent freezing in cold weather but can also help cooling in hot weather.

ANTI-FOAM AGENTS:
Minimize fluid foaming from the whipping action encountered in the converter and planetary action.

ANTI-WEAR AGENTS:
Zinc agents that control wear on the gears, and thrust washers.

ANTI-LOCK BRAKING SYSTEM:
A supplementary system to the base hydraulic system that prevents sustained lock-up of the wheels during braking as well as automatically controlling wheel slip.

ANTI-ROLL BAR:
A stabilizer bar to reduce body roll part of the suspension, sometimes optional.

ARC:
A flow of electricity through the air between two electrodes or contact points that produces a spark.

ARMATURE:
A laminated, soft iron core wrapped by a wire that converts electrical energy to mechanical energy as in a motor or relay. When a rotated in magnetic field, it changes mechanical energy into electrical as in a generator.

ARTICULATED VEHICLE
Normaly an heavy goods vehicle consisting of two or or sometimes more ditachable wheeled units, (also called tractor unit, towed vehicle or semi-trailer).

ATDC:
After Top Dead Centre often used to measure location of engine timing.

ATF:
Automatic transmission fluid.

ATMOSPHERIC PRESSURE:
The pressure on the Earth's surface caused by the weight of the air in the atmosphere. At sea level, this pressure is 14.7 psi at 32°F (101 kPa at O°C).

ATOMIZATION:
The breaking down of a liquid into a fine mist that can be suspended in air.

AUXILIARY ADD-ON COOLER:
A supplemental transmission fluid cooling device that is installed in series with the heat exchanger (cooler),
located inside the radiator, to provide additional support to cool the hot fluid leaving the torque converter.

AUXILIARY PRESSURE:
An added fluid pressure that is introduced into a regulator or balanced valve system to control valve movement. The auxiliary pressure itself can be either a fixed or a variable value.

AUTOMATIC TRANSMISION (AUTO):
Alternative to manual transmission, mechanically or electronically controlled.

AXIAL FORCE:
A side or end thrust force acting in or along the same plane as the power flow.

AXIAL PLAY:
Movement parallel to a shaft or bearing bore.

AXLE:
Different types of shafts or beam on which road wheels are mounted.

AXLE CAPACITY:
The maximum load-carrying capacity of the axle itself, as specified by the manufacturer. This is usually a higher number than the GAWR.

AXLE RATIO:
This is a number for the ratio between driveshaft revolutions and wheel revolutions. A low numerical ratio allows the engine to work easier because it doesn't have to turn as fast. A high numerical ratio means that the engine has to turn more rpms to move the wheels through the same number of turns. (4.07:1, 3.56:1 for example)

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