Dictionary of Automotive Terms Abbreviations

DICTIONARY OF AUTOMOTIVE TERMS - "Ai"

AI: Acronym for Air Injection

AIAA: Acronym for American Institute of Aeronautics and Astronautics.

AIADA: Acronym for American International Automobile Dealers Association.

AIAM: Acronym for Association of International Automobile Manufacturers.

AIA-SAP: Acronym for Automotive Industry Association (Czech Republic).

AIA-ZAP: Acronym for Automotive Industry Association (Slovakia).

AIC: Acronym for Automatic Idling Control Valve

AIMA: Acronym for Associação dos Industriais de Montagem de Automóveis (Portugal).

Aimer: Headlight Aimer

A tool for aiming a vehicle's headlights.

Aiming: Adjusting the direction of the headlight beams to shine without blinding oncoming traffic and yet providing the maximum illumination whether in low beam or high beam.

Air

Abbreviation for Air conditioner.
A bicycling or motorcycling term describing the space or gap between the tires and the ground when the bike takes a jump. Both tires must be off the ground before it can be called "air" as in the expression, "I really caught air on that last jump."
A gas containing approximately 80% nitrogen, 20% oxygen, and a small portion of other gases and water vapor. One of the essential factors in a Combustion engine (fuel, air, proper proportion of mixture, Compression, Timing, and Spark).
A gas for combustion, heating, cooling, ventilation, breathing, and other uses.

Also See
Ambient air
Atmospheric Air
Charge air
Cold air
Dilution Air
Discharge Air
Driver air bag
Electric air control valve
Electric air switching valve
External mix air cap
False Air
Fuel air mixture
Fuel-air ratio
Furnace Central Warm Air
Heater air pipe
Idle air bleed screw
Idle air jet
Internal mix air cap
L-jetronic air flow meter
Lateral air passage
Low-profile air cleaner
Modular air strut
Oil bath air cleaner
Paper air cleaner
Passenger-side air bag
Primary Air
Propane Air
Proper proportion of air and fuel
Pulse air principle
Pulse air system
Ram air
Recirculated Air
Return Air
Secondary air
Standard Air
Stratification Of Air
Supply Air
Ventilation Air

AIR: An acronym for Air Injection Reactor system of reducing objectionable Exhaust emissions. A belt-driven pump sends air through a pipe to the exhaust manifold and/or catalytic converter to help control emissions. Replacement for the term EAC
Also See
Air injection

Air Act: See
Clean Air Act

Air Act Amendments of 1990: See
Clean Air Act Amendments of 1990

Air and fuel: See
Proper proportion of air and fuel

Air Anti-backfire Valve: See
Secondary Air Anti-backfire Valve

Air aspirator system: (AAS) A passive air injection system that uses a one-way valve instead of an air pump to introduce extra air into the exhaust stream.

Air aspirator valve: A device that uses a diaphragm to draw air into the exhaust system to reduce emission. If a large volume of air is needed, an Air pump is used instead

Air-assisted hydraulic brake system: A hydraulic-type brake system actuated by an air hydraulic power unit.

AIRB: Acronym for Air Bypass Solenoid

Air bag: A device which is part of the passive safety system. In the event of a collision, Sensors will cause the air bag to be deployed so that your head will be pillowed by the bag instead of hitting the Dash or windshield.
Also See
Driver air bag
Passenger-side air bag
Side impact air bag

Airbag: A device which is part of the passive safety system. In the event of a collision, Sensors will cause the airbag to be deployed so that your head will be pillowed by the bag instead of hitting the Dash or windshield.
Also See
Driver air bag
Passenger-side air bag
Side impact air bag

Airbag module: All the components that make up the airbag system Airbag, inflator, cover, and sensor. Also called airbag unit..

Airbag restraint system: A system which uses an airbag to restrain occupants in the event of a collision. They may be placed on the dash or doors or even in the shoulder strap. Also called passive restraint system..

Air-bag system: See
Restraint Inflatable Air-bag System
Supplemental restraint inflatable air-bag system

Airbag unit: All the components that make up the airbag system Airbag, inflator, cover, and sensor. Also called airbag module..

Air bellows: A rubber bladder or sleeve filled with compressed gas or air. Found on some suspension systems to provide cushioning.
Also see
Air suspension

Air bleed: See
Adjustable off-idle air bleed
Auxiliary air bleeds
Compensating jet
Idle air bleed screw

Air bleed screw: See
Idle air bleed screw

Airbox: The container which holds the air filter.

Air brake

A system of braking which is usually found on large truck in which compressed air pushes against a brake piston or diaphragm in order to apply the brakes to stop or slow the vehicle.
An extendable device, most commonly a hinged flap on wing or fuselage, controlled by the pilot, to increase the drag of an aircraft. Originally a means of slowing bombers to enable them to dive more steeply, it is an essential flight control on clean jet aircraft and sailplanes
A mechanical brake operated by air-pressure acting on a piston
An absorption dynamometer in which the power is dissipated through the rotation of a fan or propeller.

Airbrush

A paint spray gun used for precise detailing work and custom painting.
The act of using an airbrush.

Air Bypass Solenoid: See
Thermactor Air Bypass Solenoid

Air bypass valve: (ABPV or ABV) a backfire-suppressor valve used in air injection systems. During high engine vacuum conditions such as deceleration, it vents pressurized air from the air pump to the atmosphere in order to prevent backfiring. At other times, it sends air to the exhaust manifold. On vehicles with a three-way catalyst, it sends air to the oxidation catalyst only when the engine warms up. Also called an anti-backfire valve, diverter valve, or gulp valve.
Also See
Secondary Air Bypass Valve

Air cap: See
External mix air cap
Internal mix air cap

Air capacitor: A capacitor in which the dielectric is nearly all air, for tuning electrical circuits with minimum dielectric loss.

Air capacity: See
Breathing capacity

Air cell: A small auxiliary combustion chamber used in certain types of compression-ignition engines, for promoting turbulence and improving combustion.

Air charge temperature: (ACT) The temperature of the air being forced into the carburetor or fuel injection system. An ACT sensor measures this temperature.

Air charge temperature sensor: (ACTS) a thermistor sensor that inputs the temperature of the incoming air stream in the air filter or intake manifold to the computer. It can be located in the intake manifold (EFI systems) or the air cleaner. On carbureted vehicles, if the air is cold, it signals the choke to let off slowly. It then alters engine speed after the choke is off and below a certain temperature, dumps air from the air injection system to the atmosphere for catalyst protection.

Air cleaner

Air filter

A device which filters the air entering the engine to remove airborne impurities, dust, dirt, and bumblebees. Also called air filter.
A device using filters or electrostatic precipitators to remove indoor-air pollutants such as tobacco smoke, dust, and pollen. Most portable units are 40 watts when operated on low speed and 100 watts on high speed.

Also See
Low-profile air cleaner
Oil bath air cleaner
Paper air cleaner
Thermostatic air cleaner

Air cleaner bi-metal sensor: (ACL BI-MET) a component of a thermostatic air cleaner system. It senses the temperature of incoming fresh air and bleeds off vacuum when the air is warm. When the air is cold, the sensor directs vacuum to the air cleaner vacuum motor.

Air cleaner duct and valve vacuum motor: (ACL DV) a component of thermostatic air cleaner systems. It opens and closes the air duct valve to provide heated or unheated air to the engine in accordance with the temperature of the incoming air.

Air cleaner element: Air filter element

The replaceable filter which prevents impurities from the air which enters the combustion chamber. Also called air filter element.

Air cleaner horn: Many air cleaner Canisters have a spout or horn extending from the edge of the Canister into which the air is taken in.
Also see
Heated intake

Air cleaner intake: The neck, called a snorkel, into which air flows en route to the throttle body

Air coil: Coil on some types of heat pumps used either as an evaporator or a condenser.

Air collector: A medium-temperature collector used predominantly in space heating, utilizing pumped air as the heat-transfer medium.

Air compressor: A device which compresses air and stores the air into a tank so that the compressed air can be used in a shop to fill tires, run tools, spray paint, etc. In a vehicle, it can be used in brake systems, leveling systems, automatic tire inflation systems, and air supply systems.

Air-conditioned: The state of exchanging warm air for cold so that a vehicle or home is cooler than the outside temperature.

Air conditioner

(A/C) or (Air)

A device used to control temperature, humidity, cleanliness, and movement and sometimes the air purity, in an enclosed space
A system of devices which causes a reduction or control of the temperature and humidity within the cab of a vehicle. It was first offered on the 1941 Packard. Two types are used in vehicles Receiver-dryer type and accumulator type.

Also See
Compressor
Condenser

Air conditioner clutch compressor signal: (ACCC signal) the input to the computer regarding the status of the air conditioner clutch (engaged or disengaged).

Air-conditioning: A system or process for controlling the temperature, humidity, air movement, and sometimes the purity of the air in an enclosed space by use of a refrigeration unit powered by electricity or natural gas. Note Fans, blowers, and evaporative cooling systems (swamp coolers) that are not connected to a refrigeration unit are excluded..

Also see
Automatic air-conditioning

Air conditioning compressor

Pump of a refrigerating mechanism which draws a low pressure on cooling side of refrigerant cycle and squeezes or compresses the gas into the high-pressure or condensing side of the cycle.
An air conditioning component which pumps, circulates, and increases the pressure of refrigerant vapor

Air conditioning sensor: A Sensor which provides information that the Air conditioning compressor is operating for Idle speed control.

Air control: See
Electric air control valve

Air Control Solenoid Vacuum Valve Assembly: See
Thermactor Air Control Solenoid VacuumValve Assembly

Air control valve: (ACV) a vacuum-controlled diverter valve (or a combination bypass/diverter valve) in an air injection system that diverts air pump air to either the upstream (exhaust manifold) or downstream (oxidation catalyst) air injection points as necessary.
Also see
Auxiliary Air Control Valve
Electric Air Control Valve
Electronic Air Control Valve
Idle Air Control Valve
Thermactor Air Control Valve

Air-cooled apparatus: An electric apparatus in the heat caused by the losses is removed solely by natural or fan-assisted air flow.

Air cooled: See
Air cooled engine

Air-cooled condenser: A heat exchanger which transfers the heat of compression from condensing coils to surrounding air. This may be done either by convection or by a fan or blower.

Air cooled engine: Air cooled engine

An engine which generally has large fins or ribs and is often exposed to the outside air. The heat of the engine is dissipated through the fins of the engine. In contrast, the heat in a liquid-cooled engine is reduced by Channels throughout the inside of the engine through which liquid (Antifreeze) passes. Most older Volkswagens and Motorcycles use air cooled engines.

Air-cooled engine: See
Air cooled engine

Air-cooled machine: A machine in which the heat caused by the losses is removed solely by natural or fan-assisted air flow.

Air cooler

Mechanism designed to lower temperature of air passing through it
The cold "accumulator" used in the Lindé process of air liquefaction for the preliminary cooling of the air.

Air cooling: The cooling of hot bodies by a stream of cold air, instead of liquid (water) cooling.
Also see
Charge air cooling

Air core: Coil of wire not having a metal core.

Air core solenoid: Solenoid which has a hollow core instead of a solid core.

Air correction jet: A small orifice which permits air to enter the emulsion tube of a carburetor.

Aircraft: Any mechanically driven heavier-than-air flying machine with wings of fixed or variable sweep angle. Subdivision landplane, seaplane (float seaplane and flying boat), amphibian.

Air cushion: See
Airbag

AIRD: Acronym for AIR Diverter Solenoid

Air dam: An attachment called a " Spoiler" which is usually located below the front Bumper. Its design shape and placement helps to reduce the flow of air under the vehicle. It may help to increase the flow of air to the Radiator and engine compartment, affect Aerodynamic drag, or affect positive and negative lift.

Air deflector: A panel which is positioned at an angle on the roof of a truck or on the front of the hood to cause the air to flow over the vehicle. The hood air deflector (often made of transparent plastic) is designed to prevent bugs from hitting the windshield. British term is "air shield."

Air diffuser: Air distribution outlet or grille designed to direct airflow into desired patterns.

Air Diverter Solenoid: See
Thermactor Air Diverter Solenoid

Air drag: Resistance to the motion of a body passing through the Earth's atmosphere, most serious in the lower regions, producing changes in the geometry of the orbit, even causing the body to re-enter. More generally the term atmospheric drag is used in reference to other planets.

Air dry: Allowing paint to dry at ambient (surrounding) temperatures, without the aid of an external heat source.

Air-dry: Allowing paint to dry at ambient (surrounding) temperatures, without the aid of an external heat source.

Air drying adhesives: Adhesives that can be dried at room temperature without the use of heat. This type of adhesive consists of solid particles dissolved or dispersed in a liquid. When the liquid evaporates, it leaves the dry adhesive film. Most elastomer based adhesives are of this type.

Air duct: A tube or channel which permits heated and ventilated air to enter the passenger compartment, building, or machinery to provide heating, cooling, or ventilation.

Aired up: Said of an oil plunger pump which no longer sucks because gas or air has filled the suction chamber.

Air ejector: A type of air pump used for maintaining a partial vacuum in a vessel through the agency of a high-velocity steam jet which Entrains the air and exhausts it against atmospheric pressure.

Air engine

An engine in which air is used as the working substance. Rapid heating from an external source expands the air in the cylinder with consequent motion being imparted to a piston. After transfer to a compression cylinder, for rapid cooling, the air is returned to the working cylinder for the next cycle. Also called hot-air engine.
A small reciprocating engine driven by compressed air.
Also see
Stirling engine

Air-entraining agent: Resin added to cement or concrete to trap small air bubbles

Air exhauster

A suction fan.
A vacuum pump.

Air filter: A device for removing impurities from the air which enters the combustion chamber.
Also See
Air cleaner
Centrifugal force air filter

Air filter element: Air Filter Element

The replaceable filter which prevents impurities from the air which enters the combustion chamber. Also called Air cleaner element.

Air filtration: See
Air filtration system

Air filtration system: A system that cleans Smog, pollen, Exhaust smoke, and odors out of the air. Cleans both interior circulated air and that coming from the outside.

Airflow: The passage of air which moves around an object (esp. a vehicle) or through an Air duct (e.g., ventilation system or exhaust system).
Also See
L-jetronic air flow meter
Hot-wire airflow meter
Mass airflow meter

Air flow controlled fuel injection: (AFC) a Bosch term for its early pulse fuel injection systems; usually refers particularly to the system which uses an L-Jetronic air mass sensor.

Air flow meter

A meter which measures the rate at which air enters the engine. In Bosch systems, any device that measures the amount of air being used by the engine. The control unit uses this information to determine the load on the engine. The two most common examples of airflow meters are the air-flow sensor used in the Bosch L-Jetronic and the air mass sensor used in the Bosch LH-Jetronic systems.
An instrument, mainly experimental, for measuring the airflow in ducts

Also See
L-jetronic Air Flow Meter
Hot-wire airflow meter
Mass airflow meter
Vane Air-flow Meter

Airflow meter: See
Air flow meter

Air flow sensor

A device in an electronically controlled fuel injection system which detects the amount of air entering the combustion chambers. Continuous injection systems use an airflow sensor plate to measure airflow volume; electronic systems use a vane or flap-type airflow sensor.
A Sensor that provides information on the volume flow or mass flow rate of the intake air to the engine.

Air foil: Air foil

An aerodynamic device used to improve Traction by increasing the downward force on either end of the car. It can be compared to an airplane wing with this primary difference A wing is designed to provide lift so it can fly; the air foil pushes the vehicle closer to the ground. Although they may be called "wings," they are properly air foils. They increase the cornering ability, improve Stability, but add Aerodynamic drag.

Airfoil section: The cross-sectional shape or profile of an airfoil.

Air fuel: See
Air-fuel ratio

Air-fuel: See
Air-fuel ratio

Air/fuel: See
Air-fuel ratio

Air-fuel mixture: See
Lean air-fuel mixture
Rich air-fuel mixture

Air fuel ratio: See
Air-fuel ratio

Air-fuel ratio: (A/F ratio) The mass of air supplied to the engine divided by the mass of fuel supplied in the same period of time (i.e., ratio of air weight to fuel weight). The Stoichiometric, or chemically correct, air-fuel ratio is the exact ratio necessary to burn all the Carbon and Hydrogen in the fuel to carbon dioxide and water with no Oxygen remaining. The Fuel-air ratio is the reciprocal of the air-fuel ratio.
Also See
Lean air-fuel mixture
Rich air-fuel mixture

Air Furnace: See
Central Warm Air Furnace

Air gap

The space between the magnetic poles or between rotating and stationary assemblies in a motor or generator
In a Regulator it is the distance between the contact Armature and the iron Core that when magnetized, draws the armature down.
The distance or space between the Reluctor tooth and Pick up coil
The distance between the two Electrodes of a Spark plug.
Also see
Spark air gap
Gap with points or knobs, adjusted to breakdown at a specified voltage and hence limit voltages to this value.
Section of air, usually short, in a magnetic circuit, esp. in a motor or generator, a relay, or a choke. The main flux passes through the gap, with leakage outside depending on dimensions and permeability.

Air-guard: (AG) An American Motors air injection system that uses an air pump to supply air into the exhaust manifold to reduce HC and CO emissions.

Air gulp system: A system in vehicles with secondary air injection or induction, which prevents an very rich mixture of air-fuel from entering the inlet manifold during deceleration. If it did enter, unburned fuel would be forced over the hot exhaust system causing backfiring (i.e., uncontrolled detonation). The air gulp system prevents this condition by allowing a quantity of air to combine with the rich mixture in the inlet manifold.

Air gulp valve: A diverter valve which adds an amount of air to the rich air-fuel mixture entering the intake manifold during deceleration.

Air hammer: Air Hammer

A hammer-tool that is powered by compressed air

Air handler: Fan-blower, heat transfer coil, filter, and housing parts of a system.

Airheads: A term for older, air-cooled BMW Boxer Twin motorcycles.

Air hold fitting: A tool which uses air pressure to keep the valves closed when working on an OHV engine. The device is screwed into the spark plug holes and air pressure keeps the valves from dropping down. In this way the valve seal or valve spring can be replaced without removing the cylinder head.

Air horn

Carburetor Air Horn

The upper part of a Carburetor into which the air is drawn. The Choke butterfly is located in this air horn.
It is also a term used for a warning horn which is operated by forcing compressed air through a reed.

Air horn baffle: Used on some Rochester Quadrajet carburetors to prevent incoming air from forcing fuel into the secondary wells through the bleed tubes. Prevents secondary-nozzle lag during heavy acceleration.

Air hydraulic brake power-assist unit: A unit consisting of an air cylinder or chamber, hydraulic cylinder(s) and control valve in which driver effort is combined with force from the cylinder piston or chamber diaphragm to displace fluid under pressure for actuation of the brake(s).

Air-hydraulic system: An air brake system that uses a single air chamber to power a hydraulic master cylinder that applies the wheel friction assemblies through conventional brake calipers and wheel cylinders.

Air induction: See
Air injection
Cold air induction

Air infiltration: Leakage of air into rooms through cracks, windows, doors, and other openings.

Air injection: A system that injects fresh air into the Exhaust ports or a Thermal reactor, for additional conversion of Carbon monoxide to carbon dioxide and Combustion of unburned Hydrocarbons (unburned fuel vapors) found in the Exhaust gases as it comes in contact with the high heat in the Exhaust manifold. Also called air induction..

Air injection manifold: The duct inside the cylinder head or the tube outside the cylinder head feeding secondary air into the exhaust ports.

Air injection reaction: See
Air Injection Reaction system

Air injection reaction system: (AIR system) The AIR system helps to reduce Hydrocarbons and Carbon monoxide levels in the Exhaust by injecting air into the Exhaust ports of each Cylinder during cold engine operation, or directly into the Catalytic converter during normal operation. It also helps the Catalytic converter to reach proper operating temperature quickly during warm-up. If a GM car has an Air pump, the system is an AIR otherwise it is a PULSAIR system.

Air injection system: (AIS) any system that injects air into the exhaust stream to promote more complete oxidation of unburned exhaust gases.

air inlet: See
Primary air inlet

Air Inlet System: See
Heated Air Inlet System

Air inlet valve: An adjustable door, often vacuum operated, in the plenum blower assembly that permits election of outside or inside air for automotive heating and cooling systems.

Air intake

Any opening introducing air into an aircraft; the opening for the main engine air is usually implied if unqualified.
The opening through which air enters a component such as the carburetor, fuel injection system, radiator, heating system, or ventilation system.
Vent in a carburetor through which air is sucked to mix with the gasoline vapor from the jet.

Also see
Auxiliary air intake
Cold air intake

Air-intake guide vanes: Radial, toroidal or volute vanes which guide the air into the compressor of a gas turbine, or the supercharger of a reciprocating engine.

Air jet: See
Idle air jet

Airless spraying: A paint spraying process where the coating material (i.e., paint) is not atomized by a stream of air. Instead, it is subjected to high pressure and forced through a narrow jet or nozzle which causes it to be atomized.

Airless spray gun: Airless spray gun

A paint spraying tool used in Airless spraying.

Air line

A pipe, hose, or duct in a vehicle which permits the flow of air or vacuum.
The supply line coming from an air compression tank to drive air tools or inflate tires.
Straight line drawn on the magnetization curve of a motor, or other electrical apparatus, expressing the magnetizing force necessary to maintain the magnetic flux across an air-gap in the magnetic circuit.

Air liquefier: A type of gas refrigerating machine based on the Sterling or hot-air engine cycle.

Air lock

A bubble of air trapped in a fluid circuit which interferes with normal circulation of the fluid.
Device by which access is obtained to the working chamber (filled with compressed air to prevent entry of water) at the base of a hollow caisson. The worker at surface enters and is shut in an air-tight chamber filled with air at atmospheric pressure. Pressure within this air-lock is gradually raised to that used in the working chamber, so that the worker can pass out through another door and communicate with the working chamber.

Air management system: (AMS) used to control the injected air to the exhaust manifold and catalytic converter. This improves the pollutant conversion efficiency in the converter.

Air mass flow: In a gas turbine power plant, the quantity of air which is ingested by the compressor, normally expressed in pounds or kilograms per second.

Air mass meter: An instrument which measures both engine intake air mass and factors which affect air density, such as temperature, humidity, and pressure.

Air mass sensor: An airflow meter that uses the changing resistance of a heated wire in the intake airstream to measure the mass of the air being drawn into the engine. Also referred to as a hot-wire sensor.

Air meter: An apparatus used to measure the rate of flow of air or gas.

Air micrometer: A control in a paint spray gun which adjusts the amount of air.

Air mixture: See
Fuel air mixture

Air outlet: The vent or opening where the passage of air exits -- especially in systems for air conditioning, ventilation, and defrosting as air enters the passenger compartment or flows out of the compartment.

Air outlet valve: A vacuum operated door which directs air flow into the heater core or ducts, usually located in or near the plenum blower assembly. A vacuum operated door which directs air flow into the heater core or ducts, usually located in or near the plenum blower assembly.

Air Over: (AO) An electric motor intended for Fan and Blower service and cooled by the air stream from the fan or blower

Air passage: See
Lateral air passage

Air pipe: See
Heater air pipe

Air pollution: Contamination of the earth's atmosphere by various natural and man-made pollutants such as smoke, gases, dust, etc.

Air pressure

The Atmospheric pressure.
Tire pressure.
The force of air coming from a compressor used to power air tools or apply air brakes.

Air Principle: See
Pulse Air Principle

Air Pulse Valve: See
Secondary Air Pulse Valve

Air pump

Air pump (Air Injection system)

The device that supplies the fresh air needed by the Air injection system.

Air pump

A reciprocating or centrifugal pump used to remove air, and sometimes the condensate, from the condenser of a steam plant.

Also see
Air ejector
Any device used for transferring air from one place to another. A compressor increases the pressure, a Vacuum pump reduces the pressure and a blower causes a rapidly moving air blast

Air quality: The extent to which air is free from contaminants, conventionally taken to be the respiratory irritants nitrogen dioxide and sulfur dioxide.

Air Quality Management District: (AQMD) A term used principally in California to describe administrative districts organized to control air pollution. Nationwide, AQMDs are parallel to the areas designated for classification against the National Ambient Air Quality Standards (NAAQS). Generally, AQMDs and their national parallel encompass multiple jurisdictions and closely follow the definition of Consolidated Metropolitan Statistical Areas and Metropolitan Statistical Areas.

Air Quality Standards: See
National Ambient Air Quality Standards

Air ratchet: Air ratchet

A Ratchet tool powered by air pressure from an air compressor

Air ratio: The ratio of actual intake air volume to the air volume theoretically needed for complete combustion of a particular amount of the fuel. This ratio is represented by the Greek letter lambda (which looks like the letter y upside-down).
Also see
Fuel air ratio

Air receiver: An air tank which holds the compressed air created by a compressor.

Air-recirculation system: See
Automatic air-recirculation system

Air Regulator: See
Auxiliary Air Regulator

Air resistance: The Resistance of the air to forward movement, sometimes called Aerodynamic drag. This is a factor of the shape of the vehicle, the objects which stick out (i.e., mirrors, Mufflers, Bumpers), the amount of turbulence at the rear of the vehicle, the nature of the vehicle's skin surface, and the amount of air going through the vehicle for cooling and Ventilation. The faster you go, the greater the air Friction (air friction = velocity x velocity). The faster you go, the greater the amount of power needed to overcome this Drag (power = velocity x velocity x velocity).

Air Resources Board: See
California Air Resources Board

Air Ride Suspension: (ARS) A suspension system in which the load is supported on air-filled rubber bags rather than steel springs. The engine's air compressor fills the reservoir tanks which supplies air for the suspension and the air brake system.

Air scoop: Air Scoop

A forward facing aerodynamic device or opening used to Duct cool outside air to some part of the vehicle such as the Carburetor Intake, the brakes, the Radiator, or an Oil cooler.

Airscoop: See
Air scoop

Air screw: Any type of screw designed to rotate in air; defined in 1951. Term now obsolete and replaced by Propeller, a device for propelling aircraft, and Fan, a rotating bladed device for moving air in ducts or wind tunnels.
Also see
Bypass air screw
Rotor.

Air select valve: A valve in a two-stage catalytic converter with secondary air injection. It is operated by a solenoid and is triggered by the electronic control module. It directs air to the exhaust valve ports or to the midbed catalytic converter, depending on operating conditions.

Air-sensing thermostat: The unit in which sensing element is located in refrigerated space.

Air sensor

A device which checks for the presence of air pollutants entering the passenger compartment. If the pollutant concentration is too high, it operates flaps to cut off the external air to the air conditioning system.
An air cone with a floating plate which measures air flow and determines plunger position on K-Jetronic type systems

Air shield: British term for Air deflector.

Air shock absorber: A shock absorber or damper which has a rubber bladder filled with compressed air. As the air pressure increases the vehicle is raised. The system is used in automatic leveling suspensions.

air shutter: An adjustable device for varying the size of the Air inlet(s) regulating primary or secondary air.

Air silencer: A device which is placed in the air cleaner assembly to reduce the sucking noise that air makes as it enters.

Air solenoid: See
Bypass air solenoid

Air-spaced coil: Inductance coil in which the adjacent turns are spaced (instead of being wound close together) to reduce self-capacitance and dielectric loss.

Airspeed: See
Calibrated Airspeed

Air spring: A high pressure air-filled spring used in the suspension fork of some bicycles or the suspension of some cars.
Also See
Air bellows
Air suspension

Air springing: See
Air suspension

Air, standard: See
Standard air

Air standard cycle: A standard cycle of reference by which the performance of different internal-combustion engines may be compared, and their relative efficiencies calculated.

Air standard efficiency: The thermal efficiency of an internal-combustion engine working on the appropriate air standard cycle.

Air stop: A registered trademark for Michelin tubes.

Air Strut: See
Self-levelling suspension strut

Air-suspended power booster: A type of power booster that contains atmospheric pressure in both chambers of the booster when the brake pedal is at res. When the pedal is applied, the front chamber is opened to manifold vacuum, causing the diaphragm of the booster to move toward the master cylinder which assist the driver in the application of the brakes.

Air suspension: Air suspension

A Suspension system using air rather than metal springs to support the vehicle and control ride motions. Air springing results in a smoother ride, because the natural frequency of vibration of an air spring does not vary with loading as it does with metal springs. Air springs can be made very soft for the lightly loaded condition and the pressure automatically increased to match any increase in load, thus maintaining a constant sprint vibration period any load.

Air suspension power booster: A type of power booster that contains atmospheric pressure in both chambers of the booster when the brake pedal is at rest. When the pedal is applied, the front chamber is opened to manifold vacuum causing the diaphragm of the booster to move toward the master cylinder which assists the driver in the application of the brakes.

Air switching: See
Electric air switching valve

Air switching valve: (ASV) a valve in an air injection system that senses intake manifold vacuum and during heavy loads, dumps part of the air pump output to the air cleaner to reduce air injections system pressure.
Also see
Electric air switching valve
Secondary Air Switching Valve

AIR system: See
Air injection reaction system

Air system: See
Pulse air system

Air tank: An air container which holds the compressed air created by a compressor.

Air temperature: See
Ambient air temperature

Air temperature sensor: (ATS) A device which detects the fluctuation of temperature in the air conditioning system so that the temperature in the cab of a vehicle can be maintained.
Also see
Intake Air Temperature Sensor
Manifold Air Temperature Sensor
Vane Air Temperature Sensor

Air-to-air intercooler: A heat exchanger used on a turbocharged engine, which uses liquid coolant from the rad to cool the air coming from the turbo into the intake manifold.

Air tool: A tool such as an impact driver or drill which is powered not by electricity, but by air pressure coming from an air compressor.

Air Toxics: Toxic air pollutants defined under Title II of the CAA, including benzene, formaldehyde, acetaldehyde, 1-3 butadiene and polycyclic organic matter (POM). Benzene is a constituent of motor vehicle exhaust, evaporative and refueling emissions. The other compounds are exhaust pollutants.

Air transformer: A device which is placed between the compressor and a paint spray gun to provide clean spraying air and to regulate the oil pressure.

Air valve: A valve in a spray gun which controls the flow of air by the operation of the trigger.
Also see
Auxiliary air valve

Air valve carburetor: See
Air-valve carburetor

Air-valve carburetor: A type in which a spring-closed or weight-closed air valve opens in response to engine demand. This valve, through suitable Linkage, varies the fuel-orifice opening to secure the desired mixture ratio throughout the range of operation. SU and Stromberg CD Carburetors operate on this principle, referred to also as Constant-vacuum, Constant-depression, or variable-Venturi.

Air volume: The amount of air.
Also see
Variable Air Volume

Air Volume Controller: See
Variable Air Volume Controller

Air volume spraying: A method of spray application which involves higher volume and lower pressure of air than high-pressure air spraying.

Airway: A passageway that allows air to enter.

AIS

Acronym for Air injection system.
Acronym for Automatic Idle Speed motor

AIT: Acronym for Air Inlet Temperature sensor--Used to measures inlet air temperature for fuelling

AIV

Acronym for atmospheric/automatic inlet valve, a system used on early motorcycle engines in which the intake valve is held shut by a weak spring and opens by atmospheric pressure when the falling piston creates a vacuum in the cylinder.
Acronym for air injection valve