Dictionary of Automotive Terms & Abbreviations

DICTIONARY OF AUTOMOTIVE TERMS

Abbreviation or symbol for absolute temperature, absorption coefficient, acceleration, adenine, ampere, amplitude, angular acceleration, area, attenuation coefficient, fine-structure constant, helium nucleus, Helmhotz free energy, magnetic vector potential, relative atomic mass, a stereoisomer of a sugar, substitution on a carbon atom next to one common to two condensed aromatic nuclei, substitution on the carbon atom next to the hetero-atom in ahetero-cyclic compound, and substitution on the carbon atom of a chain next to the functional group.

A-2 tire

A term used for tire sizes 16.00 and larger in nominal cross section. Also called earthmover or off-the-road tire.

Abbreviation for "Automobile Association" a term used in Great Britain.

AAA

Acronym for "American Automobile Association" or "Alberta Automobile Association."

AABM

Acronym for "Association of American Battery Manufacturers, Inc."

AAE

Acronym for "Association of Automotive Employers" (Poland).

AAIA

Acronym for "Automotive Aftermarket Industry Association".

AALA

Acronym for "American Automobile Labelling Act."

AAM

Acronym for "Alliance of Automobile Manufacturers".

AAP

Acronym for "auxiliary acceleration pump".

A arm

See	A-arm

A-arm A suspension linkage formed in the shape of an "A" or "V" found commonly on the front suspension. The sides of the two legs of the A-arm are connected to the chassis by rubber bushings and the peak of the A-arm is attached to the wheel assembly. In this way, the wheel can freely move up and down. Sometimes there is an upper A-arm, a lower A-arm, or both upper and lower A-arms. The British call it a "wishbone."

A-arm

A suspension linkage formed in the shape of an "A" or "V" found commonly on the front suspension. The sides of the two legs of the A-arm are connected to the chassis by rubber bushings and the peak of the A-arm is attached to the wheel assembly. In this way, the wheel can freely move up and down. Sometimes there is an upper A-arm, a lower A-arm, or both upper and lower A-arms. The British call it a "wishbone."

Also see
double wishbone

A-arm suspension

See	double wishbone

AAS

Acronym for "air aspirator system."

ABC

[1] Acronym for "aerial bunched conductors"

[2] Acronym for "automatic beam control."

ABdc##

Acronym for after bottom dead center. A term used in timing the relation of the spark and the crankshaft.

Abel flashpoint apparatus

A device for testing the flash point of gasoline.

Abhesive

A substance which does not allow two materials from sticking together, e.g., Teflon^® on frying pans. Opposite of adhesive

Ability

See
climbing ability
cold cranking ability

Aboard

See	lighter aboard ship

Aboard ship

See	lighter aboard ship

A bone

Nickname for a Ford Model "A".

ABPV

Acronym for "air bypass valve."

Abradant

A grinding powder.

Also see
abrasive

Abrade

To grind or roughen up a surface by rubbing.

Abrasion

The action of removing some of the surface through rubbing friction.

Abrasion hardness

The ability of something (e.g., metal, ceramic) to resist abrasion.

Abrasive

A hard grit used for sanding or grinding. Usually a powder e.g., silicon carbide powder.

Also see
bonded abrasive coated abrasive non-woven abrasive

Abrasive blast cleaning

In order to clean steel or remove rust from iron or scale from metal, sand or some other powder substance is forced by air pressure through a nozzle. In this way the small particles of abrasive can penetrate the metal where sanding with sandpaper cannot. Also, very small craters are formed on the surface of the metal from the blasting action. When thoroughly cleaned the metal is ready for painting. Paint adheres better to these "craters and imperfections than to a perfectly smooth surface."

Abrasive cleaner

A cleaning paste with some hard grit. It is used to remove the grime and oils from a surface or from your hands.

Abrasive disc

A circular plate (often made of plastic with hard grit embedded into it) used for grinding or sanding.

Abrasive paper

Sandpaper (a paper upon which sand or hard grit has been glued) used for sanding or grinding.

ABS

Acronym for "anti-lock brakes. The acronym ABS comes from the German anti blockier system.

Also see
copolymer

Absolute

See manifold absolute pressure sensor and POA suction throttling valve

Absolute pressure

Pressure measured from a starting point of zero in perfect vacuum. When measured by the absolute pressure scale, atmospheric pressure is 14.7 psi or 29.92 inches of mercury (in-Hg).

Also see
manifold absolute pressure sensor

Absolute pressure sensor

See	manifold absolute pressure sensor barometric absolute pressure sensor

Absolute weight

The weight (or mass) of a body in a vacuum.

Absolute zero

The point at which there is a total absence of heat, minus 459.67°F (-273.15°C).

Absorbent

A substance with the property of assimilating another substance (e.g., sponge and water).

Absorber

Something which converts the dynamic energy of motion into potential energy (e.g., of a spring) such as in a shock absorber.

Also see
air shock absorber arc absorber adjustable shock absorbers damper	direct-acting shock absorber double-tube shock absorber friction shock absorber gas shock absorber	impact absorber lever-type shock absorber monotube shock absorber self-levelling shock absorber	shock absorber single-tube shock absorber. telescopic shock absorber UV absorber

Absorber rod

See	control rod

Absorber tower

See	shock absorber tower

Absorbing

See	energy absorbing steering column energy absorbing bumper

Absorbing bumper

See	energy absorbing bumper

Absorbing steering

See	energy absorbing steering column

Absorbing steering column

See	energy absorbing steering column

Absorption

The use of a chemical or filter to remove unwanted particles or characteristics from something.

Also see
acoustic absorption air absorption atmospheric absorption sound absorption

Absorption capacitor

A capacitor connected across a spark gap to reduce the discharge.

Absorption coefficient

[1] The volume of gas, measured at stp, dissolved by unit volume of a liquid under normal pressure (i.e., one atmosphere).

[2] The fraction of the energy which is absorbed.

Also see
acoustic absorption coefficient

Absorption dynamometer

A measuring device which absorbs and dissipates power, e.g., the ordinary rope brake and the Froude hydraulic brake.

Absorption factor

See	acoustic absorption factor

ABS override button

A button or switch which disengages the automatic anti-lock braking system so that the driver can operate the brakes himself.

ABS relay valve

An electrically controlled valve which modulates the air pressure in the ABS.

Abut

The action of two gear teeth making contact.

Abutment

[1] A part which stops the motion of another part from proceeding any farther.

[2] The contact made between opposing teeth of two gears.

Abutting edge

The edge or side of a panel which joins the edge or side of another panel.

ABV

Acronym for "air bypass valve."

A/C

[1] An abbreviation for air conditioning or air conditioner.

[2] An abbreviation for "across corners" which indicates the distance on a nut (for instance) from one corner to the opposite corner rather than the distance from one flat surface (A/F) to the opposite (which would be the size of wrench needed to install or remove the nut). The purpose of the A/C dimension is to know how large a hole might be needed to insert a recessed nut.

[1] A vehicle brand of which the 1925-48 models are classic cars.

[2] Acronym for "alternating current."

[3] Acronym for "air conditioning" or "air conditioner."

[4] Symbol for actinium

[5] The transformation temperature on heating of the phase changes of iron or steel, subscripts indicating the designated change, e.g., Ac₁ is the eutectoid (723°C) and Ac₃ the ferrite/austenite phase boundary.

AC Ace

A vehicle brand of which the 1954-61 Ace models are milestone cars.

AC Aceca

(pronounced ah-SEEK-uh) A vehicle brand of which the 1955-61 Aceca models are milestone cars.

ACAP

Acronym for "Associação do comércio automovóvel de Portugal".

AC Buckland

A vehicle brand of which the 1949 Buckland Open Tourer is a milestone car.

Acc

Abbreviation for "accessories."

ACC

[1] Acronym for "Automatic Cruise Control."

[2] A term found on a cruise control switch which indicates the direction the switch needs to be moved to increase the speed (accelerate) of the vehicle.

ACCC

Acronym for "air conditioner clutch compressor" signal.

Accelerate

[1] To increase the speed of a vehicle. Opposite of decelerate.

[2] To speed up the chemical reaction or curing process of an adhesive. For example, you can speed up the drying time of an adhesive or sealer by increasing the temperature. Also, by adding a chemical curing agent, or accelerator, to a base compound.

Accelerating machine

See	accelerator

Accelerating-well ports

These ports prevent momentary leanness during the period that occurs between the opening of the air valve and the actual discharge of fuel from the secondary nozzles.

Acceleration

The rate of change of velocity or speed. Velocity is steady and is measured in distance per time (e.g., feet per second, miles per hour, kilometers per hour). Acceleration keeps increasing and is measured in velocity per time (e.g., feet (or meters) per second per second or feet (or meters) per second squared). It is a vector quantity and has both magnitude and direction.

Also see
angular acceleration lateral acceleration sluggish acceleration yaw acceleration

Acceleration enrichment

The action of increasing the fuel/air mixture during acceleration in order to improve the vehicle's speed and its smooth response.

Acceleration pump

See	auxiliary acceleration pump

Acceleration slip regulation

( ASR) The Bosch term for traction control.

Acceleration stress

The influence of acceleration (or deceleration) on certain physiological parameters of the human body. The degree of tolerance depends on the magnitude and duration of the acceleration as well as the direction of the force against his body.

Acceleration tolerance

The maximum acceleration force that a person can withstand before "blacking out" or otherwise losing control.

Accelerator

[1] In automobiles, this is the "gas pedal" which is attached by linkage to the throttle in the carburetor or to the fuel injection system. It regulates the amount of fuel which is sent to the engine. In motorcycles, the accelerator is located on the right-hand twist grip or an actuating lever.

[2] A chemical which is added to something to make a process happen more quickly. For example, a chemical may be added to paint to cause it to dry faster. The opposite is "retarder." A material added to an adhesive to speed up its cure or to chemically convert the whole mass to a solid. Accelerators differ from catalysts in that they are a part of the chemical reaction and lose their chemical identity as a result.

[3] Any substance increasing the speed of the vulcanization process of rubber.

Also see
depress the accelerator ease up on the accelerator step on the accelerator take foot off the accelerator

Accelerator interlock

A connection between the gas pedal and the automatic transmission.

Accelerator pedal

The accelerator, gas pedal, or throttle pedal.

Accelerator pump

A small cylinder and piston usually located inside the carburetor that sprays an extra amount of fuel into the engine during acceleration. It improves acceleration by giving more boost and reducing a momentary lag in power. It is actuated by depressing the pedal.

Accelerometer

An instrument which measures the amount of acceleration in a specific direction.

Also see
impact accelerometer vertical-gust recorder

Acceptable quality level

(AQL) A manufactured good that may not be perfect but does reach a level of shape, size, and performance, etc. that will make it work and last as long as the manufacturer expects.

Acceptance test

An examination of a part or its assembly to determine if it meets a prescribed standard.

Access

A way of reaching something that is usually hidden or covered.

Also see
access panel

Access Cab

A type of pickup truck (by Toyota) which as a second row of seating; but unlike a crew cab (which has four full size doors) it has a "half-door" that can be opened only after the main door is opened. The seating is usually a little more cramped than in a crew cab. Also called club Cab, extended Cab, king Cab, xtracab, supercab, or cab Plus

Access hole

An opening through which you can reach something. It is usually covered with a panel.

Accessible hermetic

Assembly of motor and compressor inside a single bolted housing unit.

Accessories

Items and packages of equipment which are beyond the standard equipment supplied in a new vehicle.

Accessory

See	accessories

Accessory gearbox

A transmission, driven remotely from the main engine, to which other items (e.g., generator, pumps) are mounted.

Accessory package

A set of features or appointments which may be ordered at extra cost on a new vehicle.

Access panel

The cover which conceals the engine on a mid-engine vehicle. Also called engine cover.

Also see
hood

Accident

See	car accident

Accident damage

The destruction caused to a vehicle's bodywork when it is involved in an accident.

Ac circuit

A circuit which passes only alternating current as opposed to direct current, e.g., it may have a capacitor in series, which blocks direct current.

Ac commutator motor

An ac motor which has a commutator as an essential part of its construction.

Also see
ac series motor compensated induction motor repulsion motor Schrage motor

Accord

A model of automobile manufactured by Honda

.
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Honda Accord

Accumulator

[1] A storage battery for an electric car.

[2] A pressurized container for an automatic leveling suspension system.

[3] A part of the hydraulic system which is charged by the fluid pump, absorbs fluctuating fluid delivery, stores fluid at pressure, and can provide a rapid flow of fluid under pressure.

[4] A vessel that stores hydraulic fluid under pressure.

[5] A storage tank which receives liquid refrigerant from evaporator and prevents it from flowing into the suction line before vaporizing.

[6] A refrigerant storage device used on General Motors and Ford systems that receives vapor and liquid refrigerant from the evaporator. The accumulator, which contains "desiccant," performs a function similar to that of a receiver-drier it separates liquid from the vapor, retains the liquid and releases the vapor to the compressor. Always located on the low side of the system.

Also see
accumulator piston fuel accumulator hydraulic accumulator pressure accumulator

Accumulator battery

A storage battery (i.e., the main battery in your vehicle).

Accumulator box

A vessel usually made of plastic which contains the plates and electrolyte of an accumulator.

Accumulator drier

A device which is part of the air conditioning system. It is made up of a tank, filter, drying agent, and a vapor return tube. It is usually found on the evaporator outlet. It stores the excess refrigerant and removes the moisture from the refrigerant (thus the name "drier").

Also see
receiver drier

Accumulator grid

The lead grid which forms one of the plates of a lead-acid accumulator having pasted plates.

Accumulator piston

A unit found in the automatic transmission to assist the servo to apply the brake band quickly and smoothly.

Accumulator system

In an automatic transmission, it includes a hydraulic accumulator piston which is controlled by a valve.

Accumulator traction

See	battery traction

Accumulator valve

A device which operates the hydraulic accumulator piston in an automatic transmission.

Accumulator vehicle

See	battery traction

Ace

An American trucker's colloquial term for someone with a class "A" licence.

Also see
AC Ace

ACEA

Acronym for "Association des Constructeurs européens d_Automobiles" (i.e., European Automakers Association).

Aceca

See	AC Aceca

Acetylene

[1] A gas composed of two parts of carbon and two parts of hydrogen. When burned in an atmosphere of oxygen, it produces one of the highest flame temperatures obtainable for welding.

Also see
oxygen acetylene cutting

Acetylene bottle

See	acetylene cylinder

Acetylene cutting

See	oxygen acetylene cutting

Acetylene cylinder

A specially built container manufactured according to I.C.C. Standards. Used to store and ship acetylene. Also called acetylene tank or acetylene bottle

Acetylene hose

A flexible medium used to carry gases from regulators to the torch. It is made of fabric and rubber.

Acetylene regulator

An automatic valve used to reduce acetylene cylinder pressures to torch pressures and to keep the pressures constant.

Acetylene tank

acetylene cylinder.

AC generator

[1] An electromagnetic generator for producing alternating emf and delivering ac to an outside circuit.

[2] A generator produces direct current (dc##) while an alternator produces alternating current (AC). Because alternators were introduced to automobile electrical systems after generators had been in use for some time, some people referred to the new alternator as "AC generator."

Ache

See	head ache rack

Ache rack

See	head ache rack

Acid

Also see
battery acid chromic acid oxalic acid

Acid deposition

After acid compounds are sent into the atmosphere (e.g., through a smokestack), it returns to the surface mixed with the rain. acid rain.

Acid rain

[1] When the smoke created by factories and vehicle exhausts is taken by the wind and joined with rain clouds, the mixture is often acidic. As a result the rain that falls to the ground (and even on your car) may damage whatever it strikes.

[2] A form of wet deposition in which acid molecules or particles in the atmosphere are returned to the surface having been washed out by rain or snow as it falls. The unnatural acidity (pH 3-5.5) is caused mainly by the oxides of sulphur and nitrogen from the burning of coal and oil.

AC Ignition System

See	continuous AC Ignition System

Ackermann

See	Ackermann steering

Ackermann steering

[1] A double-pivoting steering system where the outer ends of the steering arms are bent slightly inward so that when the vehicle is making a turn, the inside wheel will turn more sharply than the outer wheel. This is done to compensate for the greater distance the outside wheel must travel. Notice 20 degrees on left wheel and 30 degrees on right wheel

[2] Arrangement whereby a line extended from the track-arms, when the wheels are set straight ahead, should meet on the chassis centerline at 2/3 of the wheelbase from the front, allowing the inner stub-axle to move through a greater angle than the outer.

Ackermann angle

The toe-out or toe-in of a vehicle with Ackermann steering when the wheels are positioned straight ahead.

Ackermann axle

In a vehicle with Ackermann steering (at the front of the vehicle), it is a non-rotating axle that is steerable and has two pivot points (one on each end of the axle) with vertical kingpins.

ACL BI-MET

Acronym for "air cleaner bi-metal sensor."

ACL DV

Acronym for "air cleaner duct and valve vacuum" motor.

Ac motor

An electric motor which operates from a single or polyphase alternating current supply.

Also see
capacitor motor induction motor synchronous motor

Acoustics

[1] The science of sound waves including production and propagation properties.

[2] The characteristics of the interior of a car which determine the quality of sound transmission inside.

Also see
architectural acoustics atmospheric acoustics

Acquisition fee

A charge for processing a vehicle lease and is probably not negotiable. On a shorter term lease, the acquisition fee can have a large impact on the cost of the lease.

Across corners

( A/C) The distance on a nut (for instance) from one corner to the opposite corner rather than the distance from one flat surface ( A/F) to the opposite (which would be the size of wrench needed to install or remove the nut). The purpose of the A/C dimension is to know how large a hole might be needed to insert a recessed nut.

Across flats

( A/F) The distance on a nut (for instance) from one flat surface to the opposite flat surface, i.e., this is the size of the wrench needed to install or remove the nut.

Also see
across corners.

ACR tubing

Tubing used in air conditioners and refrigerators. The ends are sealed to keep tubing clean and dry.

Acrylate

A polymer used to strengthen rubber (e.g., ethyl acrylate).

Acrylic

A term relating to a type of paint made by polymerizing acrylonitrile.

Acrylic fibers

Continuous long filaments or fibers from linear polymers.

Acrylic finish

A final coating of paint which uses acrylic paint, often where the pigment and an acrylic paint are mixed together.

Also see
two-pack paint.

Acrylic paint

A type of paint made by polymerizing acrylonitrile.

Acrylic resin

A thermoplastic synthetic polymer made by polymerizing an acrylic derivative such as acrylonitrile, acrylic acid, ethyl acrylate, and methacrylate. It is used for adhesives, protective coatings, and paint finishes.

ACS

[1] Abbreviation for active control system

[2] Abbreviation for attitude control system

[3] Abbreviation for air conditioning system .

AC Shelby Cobra

A vehicle brand of which the 1962-67 Shelby Cobra models are milestone cars.

ACT

[1] Acronym for "air charge temperature."

[2] Acronym for active control technology.

Also see
active control system

Act

See	Motor Vehicle Safety Act

Acting

See	double-acting dual-acting single-acting

Action

Also see
caster action oscillating action parallel action locking pliers reciprocating action

Action brakes

See	servo action brakes

Action locking

See	parallel action locking pliers

Action locking pliers

See	parallel action locking pliers

Activate

To change an adhesive film from a dry or inactive state to a useful, sticky state.

Activated

See	cable activated

Activated carbon canister

An automotive filter in which activated carbon has been placed so that gas tank fuel vapors, which have accumulated when the vehicle is not running, are trapped in the filter. When the engine is running, hot air is forced into the filter and push out the vapors into the engine. In this way, pollution is reduced and conservation of the fuel is maintained. Also called activated charcoal trap or charcoal canister.

Activated charcoal

Charcoal treated with acid to increase its adsorptive power

Also see
activated carbon charcoal

Activated charcoal trap

See	activated carbon canister

Activator

A substance which is used to speed up the process of curing a tire. Also called activating agent.

Active braking time

The length of time (excluding the driver's reaction time) a vehicle takes to come to a complete stop after the brakes are applied.

Active material

In a storage battery, the brown peroxide of lead of the positive plates and the gray metallic lead of the negative plates upon which the sulphuric acid acts.

Active noise control system

See	anti-noise system

Active safety

The opposite of passive safety. Passive safety involves seat belts, airbags, bumpers, etc. so that in the event of an accident the passengers are protected. Active safety involves factors which will assist the driver in avoiding an accident. They include brakes, steering, handling response, acceleration, etc.

Active suspension

While conventional suspension uses springs and shock absorbers to isolate the vehicle from the bouncing movement of the wheels when it contacts rough roads, active suspension uses power actuators which are controlled by a computer. These actuators place the wheels of the vehicle in the best position to accommodate rough roads as well as compensate for different load levels.

Activities

See	Kaizen Activities

Activity factor

See	blade activity factor

Ac transformer

An electromagnetic device which alters the voltage and current of an ac supply in inverse ratio to one another. It has no moving parts and is very efficient.

ACTS

Acronym for "air charge temperature sensor."

Actual cash value

(ACV) The amount of money a dealer has invested in the purchase of a used vehicle and any additional costs to repair the unit in order to get it ready for resale.

Actuate

The action of bringing something into operation.

Actuating lever

A triggering device used to bring something into operation.

Actuating switch

A triggering device used to bring something into operation.

Actuation

See	variable valve actuation

Actuator

[1] A device which controls or operates another device.

[2] A regulating valve which converts a form of energy into mechanical motion to open or close the valve seats

Also see
hydraulic actuators

Actuator arm

A linkage connecting the diaphragm to the contact breaker platform in an advance mechanism of a distributor. Also called diaphragm link..

Acura

A vehicle brand from the Honda manufacturers

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ACV

[1] Acronym for "actual cash value."

[2] Acronym for "air control valve"

[3] Acronym for air cushion vehicle (i.e., hovercraft).

See	classified ad

Adapter

[1] A device used to connect two different types or sizes of electrical terminals

[2] A connector which links two items usually of dissimilar structure or size. (Also spelled "adaptor")

Also see
bit adapter bit adapter caliper mounting bracket carburetor adapter engine adapter increasing adapter ratchet adapter reducing adapter transmission adapter wheel adapter.

Adaptor carburetor

A device attached to a gasoline carburetor which permits an internal combustion engine to run either on gas or liquefied petroleum gas (LP gas).

Adapter plate

A plate which is placed between two different parts in order to link them. (Also spelled "adaptor plate")

Also see
transfer plate

Additive

A substance (liquid or powder) which is added to gasoline or oil and is intended to improve the characteristics of the original product.

Also see
anti-knock additive fuel additive oil additive

ADEFA

Acronym for "Asociacion de Fabricas de Automotores" (Argentina).

ADF

Abbreviation for automatic direction finding.

Adhere

To stick or be glued to something.

Adherend

[1] Each surface that is to stick to another

[2] A material which is stuck together by an adhesive.

Adhesion

[1] The force which causes two surfaces to stick together

[2] The sticking together of surfaces in contact with each other

[3] The bonding of materials with adhesives (glues, cements, binders, etc), in which the intermolecular forces between adhesive and adherend provide the bonds.

[4] The sticking together of two metals as a result of compressing them together

[5] The sticking together of two dissimilar metals because of electrical transference of electrons.

Also see
cold welding

[6] The ability of paint, primer, or glue to stick to the surface to which it is applied.

[7] The ability of a tire to grip the surface of the road.

[8] Mutual forces between two magnetic bodies linked by magnetic flux, or between two charged non-conducting bodies which keeps them in contact

[9] Intermolecular forces which hold matter together, particularly closely contiguous surfaces of neighboring media, e.g., liquid in contact with a solid.

Also see
intercoat adhesion failure limits of adhesion

Adhesion failure

See	intercoat adhesion failure

Adhesive

[1] A substance (like glue) that is used to join two substances. An adhesive must bond both mating surfaces through specific adhesion (molecular attraction), through mechanical anchoring (by flowing into holes in porous surfaces), or through fusion (partial solution of both surfaces in the adhesive or its solvent vehicle). Various descriptive adjectives are used with the term adhesive to indicate types, such as

a. physical form: Liquid adhesive, film adhesive, etc.
b. composition: Resin adhesive, rubber adhesive, silicone based, mastic, etc.
c. end use: Metal-to-metal adhesive, plastic adhesive, rubber adhesive
d. application: Sprayable adhesive, hot melt adhesive, etc.

[2] Agent for joining materials by adhesion, usually polymeric material. May be based on thermoplastic resin (e.g., polystyrene cement) or thermoset (e.g., epoxy resin). Viscosity is important for gap filling (high, as in epoxies) or surface penetration (low, as in cyano-acrylates). Also called binder, cement, or glue

Also see
automotive adhesive air drying adhesives impact adhesive separate-application adhesive

Adhesive film

A thin layer of dried adhesive.

Adhesive tape

A tape with a sticky substance on one side. It usually comes in a roll of various widths. Sometimes used to insulate electrical wires (e.g., electrical tape) or to wrap a larger object (e.g., duct tape). Often the non-sticky side is shiny (but not always) to distinguish it from the sticky side.

Adhesive weight

Lead wheel weights which have a sticky backing. It comes in strips and is applied to a wheel rim to balance a wheel. Also called tape weight..

Adiabatic

A property of being able to maintain heat evenly. It does not gain any heat or lose it.

Also see
thermal efficiency

Adiabatic change

Without changing the temperature of an enclosure or its surroundings, there is a change in the volume and pressure of the contents of the enclosure.

Adiabatic compression

Compressing refrigerant gas without removing or adding heat.

Adiabatic efficiency

The ratio of that work required to compress a gas adiabatically to the work actually done by the compressor piston or impeller.

Adiabatic engine

An engine which is very efficient in transferring combustion heat to those parts of the engine which are being cooled by the flow of anti-freeze coolant -- thus maintaining an even temperature of the engine. In this way the engine is warm enough for efficient running and it does not overheat.

Adjust

The action of putting something into its proper alignment or position. It may involve one component (e.g., He adjusted the gasket to fit properly.) or a series of components (e.g., He adjusted the poor idle -- might mean he set the ignition timing, adjusted the carburetor screws, changed the choke setting, cleaned or replaced the spark plugs, etc.)

Also see
tweak

Adjustable

A characteristic of something that can be changed, removed, or give different properties.

Also see
height adjustable steering column

Adjustable bottom bracket

[1] A component of a bicycle through which the crank fits. It has two bearing cups on either side. One cup is fixed in place while the other is removable or adjustable.

[2] This is the older type of bottom bracket before sealed cartridge bottom brackets became prevalent. The adjustable bottom bracket requires fixed and adjustable cup tools to properly tension the bearings. The bearings are not sealed, but they're easily accessible for cleaning and lubrication.

Also see
bottom bracket

Adjustable cup

The left-hand cup in a bottom bracket of a bicycle, used in adjusting the bottom bracket bearings and removed during bottom bracket overhaul. The other cup is the fixed cup.

Adjustable off-idle air bleed

Some emissions-era Rochester carburetors have a separate air passage to bleed air past an adjustment screw into the idle system. this screw is preset by the factory to produce precise off-idle air/fuel mixture ratios to meet emission-control requirements.

Adjustable part throttle

(APT) a supplementary circuit on some carburetors that can be adjusted to control part-throttle mixtures more accurately than a fixed orifice. The APT detours around the main jet, going directly from the float bowl to the discharge nozzle feed well.

Adjustable-pitch propeller

See	propeller

Adjustable-port proportioning valve

Air and fuel valves for oil or gas burners, motor operated in unison by automatic temperature-control equipment.

Adjustable rocker arm

A type of rocker arm with an adjusting nut that can be tightened or loosened to adjust valve lash.

Adjustable shock

See	adjustable shocks

Adjustable shock absorbers

Shocks with adjustable jounce and rebound characteristics can be stiffened to compensate for wear or to fine tune a suspension for a particular application such as rough roads, heavy loads, or racing.

Adjustable shocks

Shock absorbers which can compensate for varying needs of stiffness or softness. Manual types (especially on motorcycles) require that you physically make the adjustment from one level to another. Automatic types are controlled by a computer as it senses particular changes in road condition.

Adjustable spanner

British term for adjustable wrench.

Adjustable steering

See	height adjustable steering column

Adjustable steering column

See	height adjustable steering column

Adjustable variable exhaust port

A device used on two-stroke engines which automatically alters or varies the exhaust port size.

Adjustable wrench

A crescent wrench or pipe wrench. A tool which has a fixed jaw and a movable jaw which is controlled by a spiral gear. It is used to install or remove bolts and nuts of various sizes. The wrench itself comes in a variety of lengths and jaw sizes. A crescent wrench has smooth jaws while a pipe wrench has serrated jaws. British term is "adjustable spanner."

Adjusted

See	factory adjusted

Adjuster

A device for moving something into the correct position or into a different position such as a seat adjuster.

Also see
automatic adjuster automatic wear adjuster brake adjuster horizontal adjuster jet adjuster ride-height adjuster

Adjuster cam

A device for moving the shoes on drum brakes closer to the drum itself so that there is less travel when the brakes are applied.

Adjusting

Also see
electrode adjusting tool headlight adjusting screw self-adjusting

Adjusting gage

See	adjusting gauge

Adjusting gauge

A tool used to determine the small distance between two parts so that they can be brought within specifications.

Adjusting screw

A small screw usually found on carburetors, brakes, or headlights which change the way something operates, such as increasing or decreasing the amount of fuel entering the engine; or changing the idle speed; or tightening up the brakes; or changing the setting on rocker arms; or the level of the headlights.

Also see
headlight adjusting screw tappet adjusting screw valve adjusting screw

Adjusting shim

A thin washer or plate which reduces or increases the clearance between two components (depending upon where they are placed). While some valves are adjusted by screws on the rocker arm, others are set by inserting a shim to make the same adjustment.

Adjusting sleeve

A small threaded cylinder on the end of the tie rod which shortens or lengthens the rod to make changes in the toe-in and toe-out.

Adjusting spanner

See	brake adjusting spanner

Adjusting tool

Also see
brake adjusting tool electrode adjusting tool

Adjusting wrench

See	brake adjusting wrench

Adjustment

[1] Changing or modifying the position or alignment of two components.

[2] The distance of travel that a component has.

Also see
fore and aft adjustment idle mixture adjustment screw idle speed adjustment

Adjustment screw

See	idle mixture adjustment screw

Adler

The brand name of a vehicle. With required application the 1925-48 models are classic cars.

Admission

The point in the working cycles of a steam or internal-combustion engine at which the intake valve allows entry of the working fluid into the cylinder.

A-dos

See	dos-a-dos

A-drier

See	a-dryer

ADS

Abbreviation for air data system.

A-dryer

A paint dryer which has the heating elements below the paint drying line.

ADS

Acronym for "Association of Diesel Specialists."

Adsorbent

Substance with the property to hold molecules of fluids without causing a chemical or physical change.

Adsorption

The bonding that takes place when a gas or vapor comes into contact with a solid. The opposite is desorption.

Adsorption canister

See	activated carbon canister

Advance

[1] The act of changing the ignition timing so that the spark occurs earlier in the cycle. The opposite is retard.

[2] It may refer to the device which makes this adjustment.

[3] The length of railway track beyond a signal which is covered by that signal

Also see
angle of advance automatic advance centrifugal advance electronic spark advance ignition advance mechanical advance ported vacuum advance spark advance speed control vacuum advance vacuum advance

Advance capsule

See	vacuum advance

Advance curve

As the speed of the engine increases the ignition advance also increases. On paper, a pattern is drawn as a curve to represent this relationship.

Advanced

[1] A condition in which something occurs early.

[2] A product which is on the cutting edge of technology and shows the latest in new ideas and concepts.

Advanced rim taper

A rim where both bead seats are tapered 5°.

Advance mechanism

See	vacuum advance mechanism

Advance spring

A small spring which pulls the advance weight back.

See	picture in advance weight

Advance unit

See	vacuum advance unit

Advance weight

One of two small weights located in a centrifugal advance assembly.

Advertising

A colloquial term for a police car with its emergency lights flashing.

AEA

Acronym for "Automotive Electric Association" or "Automotive Electronic Association."

AERA

Acronym for "Automotive Engine Rebuilders Association."

Aeration

A foaming of a liquid because air has been introduced into the fluid. When it occurs in certain liquids, it decreases the efficiency of the liquid.

Aerial

British term for antenna.

Also see
retractable aerial whip aerial

Aerial bunched conductors

(ABC) Method of power transmission where the three conductors are twisted into a thicker insulated cable. More expensive but better at surviving blizzard conditions than normal separate conductors.

AERO

Abbreviation for "Air Education and Recreation Organization" in the UK.

Aero-

Prefix from Greek aer (αερ) indicating "air."

Aerobar

An extension to bicycle handlebars which project forward to give the rider an alternate riding position and a lower, more aerodynamic position. His elbows rest in the pads while he grabs the upright ends of the bars. Aerobars were popularized by triathletes and Greg Le_Mond.

Aerobars

Sometimes referred to as Tri bars. Aerobars popularized by triathletes and Greg Le_Mond, are attached to handlebars in order to provide a rider with a lower, more aerodynamic position.

Aerobic sealer

A substance (such as room temperature vulcanizing ( RTV), a common silicone rubber sealing compound) that requires the presence of oxygen to hold parts together.

Also see
anaerobic sealer

Aerodynamic

The efficient flow of air around an object.

Aerodynamic balance

A balance, usually but not necessarily in a wind tunnel, designed for measuring aerodynamic forces or moments.

Aerodynamic center

The point about which the pitching moment coefficient is constant for a range of airfoil incidence.

Aerodynamic drag

The resistance of the air to forward movement, sometimes called "air resistance." This is a factor of the shape of the vehicle (drag coefficient and frontal area), 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).

Aerodynamic heating

The heating of a vehicle passing through the atmosphere, caused by friction and compression of air (or other gas).

Aerodynamics

The study of the flow of air as it passes over and around a moving object as well as the forces which the air makes on the object. An airplane, for instance, needs positive lift to get it airborne and negative lift to help it land. Thus the shape of a land vehicle (car, bicycle, etc.) either promotes positive or negative lift. Race cars may use spoilers and wings (air foils) to control lift. In vehicle design, the airflow is monitored in a wind tunnel. As well, aerodynamics also studies the most efficient shapes for increased speed and fuel economy.

Aerodynamic stance

In order to create less drag, the vehicle is lowered closer to the ground. This improves the flow of air over the vehicle. A better aerodynamic stance helps the vehicle to go faster when it is going in a straight line as well as give better fuel economy. Also, when a vehicle sits lower to the ground, it has a low center of gravity which makes it more stable when going through turns and enables the driver to maintain a higher speed.

Aero-engine

The power unit of a small aircraft.

Also see
ducted fan gas turbine ramjet turbojet turboprop turboramjet turborocket variable cycle engine

Aerofoil

British spelling for airfoil a body or body panel shaped like a wing so as to produce an aerodynamic reaction (lift) normal to its direction of motion, for a small resistance (drag), in that plane; e.g., a wing, plane, aileron, tailplane, rudder, or elevator.

Also see
air foil

Aeroplane

British spelling for airplane.

Also see
aircraft airplane

Aero system

A roof rack designed for cars without external rain gutters. The rack is held on by clips that extend down into the door.

Aether

See	ether

AEV

Acronym for automatic expansion valve.

A/F

[1] Abbreviation for "across flats" which is the distance on a nut (for instance) from one flat surface to the opposite flat surface, i.e., this is the size of the wrench needed to install or remove the nut.

Also see
across corners

[2] Abbreviation for "air/fuel."

See	air-fuel ratio

[3] Abbreviation for "automatic focusing"

[4] Abbreviation for "audio-frequency."

AFB

Acronym for "Aluminum four-barrel," as in Carter AFB carburetor.

AFC

[1] Acronym for "air flow controlled"

[2] Abbreviation for "automatic frequency control."

AFCS

Abbreviation for automatic flight control system.

AFM

Abbreviation for audio-frequency modulation.

A-frame

A chassis frame which is shaped like the letter "A" where the crossbar is often the axle. It is usually found as the frame of a trailer.

Also see
shear-legs

A-frame barricade

A traffic marker indicating that the road is not usable.

A/F ratio

See	air-fuel ratio

Aft

The back of a vessel.

Also see
fore and aft adjustment

Aft adjustment

See	fore and aft adjustment

Aft cg limit

See	cg limits

After bottom dead center

(ABdc##) The position of the piston as it starts its way up.

Afterburner

A device for burning excess carbon wastes produced by the engine so that air pollution is reduced.

Also see
reheat

Afterburning

In an internal-combustion engine, persistence of the combustion process beyond the period proper to the working cycle, i.e., into the expansion period.

Afterburst

Delayed further collapse of underground workings after a rockburst.

Aftercooler

[1] A device in a diesel engine which removes the relatively warm air which enters the engine.

[2] Chamber in which heat generated during compression of air is removed, allowing cool air to be piped underground.

Afterglow

[1] The period during which the glow plugs of a diesel engine continue to operate after the engine is started.

[2] The glow of a gaseous medium immediately after the cessation of electric current or downstream of an electric discharge.

Also see
persistence

Aftermarket

All products and services used in the repair and maintenance of vehicles after the vehicle has been sold.

Aftermarket equipment

Accessories and replacement parts added to a vehicle after it has been sold.

Aftermarket overdrive

An overdrive device which is not original equipment, but has been added after it has been sold.

Aftermarket part

Goods not for use as original equipment in the production of light-duty vehicles or heavy-duty vehicles, i.e., products and services used in the repair and maintenance of these vehicles.

Aftermarket rustproofing

Although most vehicles come from the manufacturer with some rustproofing, there is no guarantee that every part of the exposed chassis and frame will be protected from the elements and the possibility of rust. Therefore rustproofing is applied by the owner of the vehicle to reduce the possibility of rust. If this rustproofing is not done when the vehicle is new, it might seal in the rust and create a greater problem.

After-start enrichment

When an engine is first started, it needs a little richer fuel-air mixture (i.e., more fuel, less air). In a carbureted engine, this is accomplished by the choke (which restricts the amount of air). In a fuel injected engine, the after-start enrichment device increases the amount of fuel. As the engine warms up, the device gradually reduces the amount of enrichment. Some devices just reduce the amount gradually over time without sensing the temperature of the engine.

After top dead center

(ATdc##) A term used in timing the relation of the spark and the crankshaft. The position of the piston as it starts its way down.

Acronym for "air-guard."

AGC

Abbreviation for automatic gain control.

Agency

See	driver and Vehicle Licensing Agency energy Protection Agency

Agent

An intermediary with legal authority to operate on behalf of the manufacturer.

Also see
activating agent addition agent aggressive agent air-entraining agent anti-knock agent bonding agent degreasing agent oxidizing agent reducing agent release agent rustproofing agent softening agent

Agent fee

Although you can register your vehicle and obtain your licence from a government office, some states and provinces permit an agent to perform that same service and allow the agent to collect an extra fee for the service. In this way the lineup at the government office is reduced.

Aggressive

A French expression to indicate the reinforced front, rear, and side safety structures of a vehicle. If the strengthened structure causes more than normal damage to another vehicle, a pedestrian, or the occupants of the vehicle, then that structure is aggressive.

Aging

[1] The cracking, checking, or general deterioration produced by exposure of an adhesive, coating or sealer to the weather or some other given set of conditions for a length of time

[2] The deterioration of rubber properties by oxidation over a period of time.

[3] A change in the properties of some metals after heat treatment or cold working (i.e., hammering or bending when metal is cold).

[4] The final stage of precipitation hardening, producing an increase in strength and hardness in metal alloys, due to precipitation of second phase particles from supersaturated solid solution over a period of days at room temperature, or several hours at an elevated temperature (called artificial aging)

[5] Loss of strength in the cladding or the pressure vessel in a nuclear reactor due to irradiation. Artificial aging would be the simulation of such processes by increasing the rate of irradiation to obtain information more rapidly

[6] Change in the properties of a substance with time. A change in the magnetic properties of iron, e.g., increase of hysteresis loss of sheet-steel laminations; also the process whereby the subpermanent magnetism can be removed in the manufacture of permanent magnets

Also see
artificial aging tire aging

Agitation cup

A type of spray gun paint container which has an agitator.

Agitator

[1] A device used to cause motion in confined fluid

[2] A device for mixing paint by shaking the container.

[3] A tank, usually cylindrical, which has a mixing device such as a propeller or airlift pump near the bottom. Finely ground mineral slurries (the aqueous component perhaps being a leaching solution) are exposed to appropriate chemicals for purpose of extraction of gold, uranium, or other valuable constituents. Types include pachuca tank or Brown agitator.

AGO

Abbreviation for automotive gas oil.

AGR

Abbreviation for advanced gas-cooled reactor.

Agreement

See	Free Trade Agreement of the Americas General Agreement on Tariffs and Trade North American Free Trade Agreement

Agreement of the Americas

See	Free Trade Agreement of the Americas

Agreement on Tariffs

See	General Agreement on Tariffs and Trade

Agreement on Tariffs and Trade

See	General Agreement on Tariffs and Trade

Aground

See	hard aground

AGS

Abbreviation for aircraft general standard.

AGVS

Acronym for "Automated Guided Vehicle System."

A.h.

Abbreviation for ampere-hour.

AHAI

Acronym for "Association of the Hungarian Automotive Industry".

AHAP

Acronym for "As High As Possible."

AHARA

Acronym for "As High As Reasonably Achievable."

Ahm

Abbreviation for ampere-hour meter.

Ahoogah

The sound of a particular kind of horn.

AHRA

Acronym for "American Hot Rod Association."

AH Rim

A wheel rim which is able to run even when the tire is flat and provides safety in case of a puncture.

AIAA

Abbreviation 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).

AIMA

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

Aimer

A tool for aiming 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

[1] Abbreviation for "air conditioner."

[2] 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."

[3] A gas containing approximately 80% nitrogen, 20% oxygen, and a small portion of other gases. One of the essential factors in a combustion engine (fuel, air, proper proportion of mixture, compression, timing, and spark).

Also see
ambient air bath air charge air cold air driver air bag electric air control valve electric air switching valve	external mix air cap fuel air mixture fuel air ratio 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	proper proportion of air and fuel pulse air principle pulse air system ram air secondary air

AIR

An acronym for "Air Injection Reactor" system of reducing objectionable exhaust emissions.

Also see
air injection

Air and fuel

See	proper proportion of air and fuel

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 bag

A device which is part of the passive safety system. In the event of an accident, sensors will cause the airbag to be deployed so that your head will be pillowed by the bag instead of hitting the dash.

Also see
driver air bag passenger-side air bag side impact air bag

Airbag

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	supple mental 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

[1] 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.

[2] 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

[3] A mechanical brake operated by air-pressure acting on a piston

[4] An absorption dynamometer in which the power is dissipated through the rotation of a fan or propeller.

Airbrush

[1] A paint spray gun used for precise detailing work and custom painting.

[2] The act of using an airbrush.

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.

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

A device which filters the air entering the engine to remove airborne impurities, dust, dirt, and bumblebees. Also called air filter.

Also see
bath air cleaner bath air cleaner 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

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 coil

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

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)

[1] A device used to control temperature, humidity, cleanliness, and movement and sometimes the air purity, in an enclosed space

[2] 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.

Also see
automatic air-conditioning

Air control

See	electric air control valve

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
electric 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

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

[1] Mechanism designed to lower temperature of air passing through it

[2] 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

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 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

[1] 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.

[2] A small reciprocating engine driven by compressed air.

Also see
Stirling engine

Air exhauster

[1] A suction fan.

[2] A vacuum pump.

Air filter

A device for removing impurities from the air which enters the combustion chamber.

Also see
air cleaner canister air filter centrifugal force air filter

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

(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

[1] 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.

[2] An instrument, mainly experimental, for measuring the airflow in ducts

Also see
L-jetronic air flow meter hot-wire airflow meter mass airflow meter

Airflow meter

See	air flow meter

Airflow 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.

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	rich air-fuel mixture lean 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. 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 gap

[1] The space bet magnetic poles or between rotating and stationary assemblies in a motor or generator

[2] Usually found on regulators, it is the distance between the contact armature and the iron core that when magnetized, draws the armature down.

[3] It is also the distance between the two electrodes of a spark plug.

Also see
spark air gap

[4] Gap with points or knobs, adjusted to breakdown at a specified voltage and hence limit voltages to this value.

[5] 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

A hammer 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

[1] The upper part of a carburetor into which the air is drawn. The choke butterfly is located in this air horn.

[2] 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 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 cars 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 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

[1] Any opening introducing air into an aircraft; the opening for the main engine air is usually implied if unqualified.

[2] The opening through which air enters a component such as the carburetor, fuel injection system, radiator, heating system, or ventilation system.

[3] 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

A paint spraying tool used in airless spraying.

Air line

[1] A pipe, hose, or duct in a vehicle which permits the flow of air or vacuum.

[2] The supply line coming from an air compression tank to drive air tools or inflate tires.

[3] 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

[1] A bubble of air trapped in a fluid circuit which interferes with normal circulation of the fluid.

[2] 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 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 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

[1] The atmospheric pressure.

[2] Tire pressure.

[3] The force of air coming from a compressor used to power air tools or apply air brakes.

Air pump

[1] The device that supplies the fresh air needed by the air injection system.

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

Also see
air ejector

[3] 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 sulphur dioxide.

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 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 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.

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 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.

Air spring

A high pressure air-filled spring used in the suspension fork of some bicycles."

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-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

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

AIR system

See	air injection reaction system

Air system

See	pulse air system

Air table

See	air-float table

Air tank

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

Air temperature

See	ambient air temperature

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 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.

Also see
constant-vacuum carburetor

Air volume

The amount of air.

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."

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.

Alain

See	Prost, Alain

ALAP

Acronym for "As Low As Possible."

ALARA

Acronym for "As Low As Reasonably Achievable." Used of radiation levels or decontamination.

Alarm

A warning sound made by a security or safety device to warn off thieves, alert the driver to take some preventative measures (e.g., secure the seat belts), or warn those around the vehicle (e.g., backup warning alarm).

Also see
back-up alarm car alarm

Alarm flag

See	flag indicator

Alarm system

A theft protection system which may do one or more of the following Sound the horn or an auxiliary siren, flash the lights, lock the hood and trunk, make the ignition inoperative, put the engine in a "limp home" mode (i.e., greatly reduce speed), notify the police, and alert the vehicle owner.

Alarmed

Protected by an alarm system.

Alcohol

[1] A general term for compounds formed from hydroxyl groups attached to carbon atoms in place of hydrogen atoms; in particular, ethanol.

[2] A substance used as fuel.

See	methanol

[3] A beverage which impairs a driver's skill in operating a vehicle safely. Although the law has set down limits of the amount of alcohol allowable in the bloodstream before a person is considered drunk, the effects of the slightest amount of alcohol can impair one's driving skill.

Also see
grain alcohol methyl alcohol wood alcohol

Alcohol content

See	blood alcohol content

Alcohol fuel

Volatile liquid fuel consisting wholly or partly of alcohol, able to withstand high-compression ratios without detonation.

Alcohol level

See	blood alcohol level

ALDL

[1] Acronym for "assembly line diagnostic link" a diagnostic connector.

[2] Acronym for "assembly line data link."

Alert

See	deer alert voice alert system

Alert system

See	voice alert system

Alfa-Romeo

A vehicle brand of which all 1925-48 models are classic cars. The following models are milestone cars

All 1956-64 Giuletta Spider models
All 1959-61 Giuletta/Giulia Sprint Speciale models
All 1949 6C 2500 Super Sport models

.
Click for books on Alfa

Alfa Romeo

See	Alfa-Romeo

Al fresco driving

Driving in a convertible with the top down.

A-licence

Basic private pilot's licence in the UK.

Align

[1] Process of bringing two or more items into mating conjunction so that all the bolt holes and locating pins fit properly.

[2] Process of adjusting the wheels and other devices so that they are in a straight line.

Align bore

A machining operation which corrects an engine's out-of-round and/or warped main bearing housings. It may be done with either stationary or portable equipment.

Also see
align hone

Aligner

See	wheel aligner

Align hone

A machining operation which corrects an engine's out-of-round and warped main bearing housings with a special honing mandrel. It must be done with stationary equipment.

Aligning punch

A tool shaped like a thin rod used to make sure holes line up when assembling two or more components. Especially used on items which may move to one side before the other side can be aligned or another component installed or when the gasket is likely to slip out of place.

Aligning set

See	clutch aligning set

Aligning tool

See	clutch aligning tool

Alignment

[1] When referring to wheel alignment, it is the proper adjustment of a vehicle's front or rear suspension for camber, toe-in, toe-out, kingpin inclination or steering axis inclination, and turning radius or toe-out on turns, caster, and ride height. Four-wheel alignment is necessary for front-wheel drive vehicles.

[2] The adjustment of two objects to bring them into the proper relation to each other.

[3] The setting in line (usually straight) of successive lengths of a railway which is to be constructed

[4] The plan of a road or earthwork

[5] The setting in a true line of a number of points, e.g., the centers of the bearings supporting an engine crankshaft

[6] Process of orientation of e.g., electric or magnetic dipoles when acted on by an external field. During magnetization, the alignment of domains is changed by the magnetizing field

[7] Adjustment of preset tuned circuits to give optimum performance

Also see
door alignment four-wheel alignment four wheel alignment front-end alignment front end alignment wheel alignment

Alignment gap

The distance between two adjacent auto body panels. When an alignment gap varies too much, it is a sign of poor assembly quality.

Alignment gauge

See	wheel alignment gauge

Alignment pin

A pin or stud used to align one part with another, such as the pins used to align a cylinder head on an engine block.

Alignment stud

A pin or stud used to align one part with another, such as the pins used to align a cylinder head on an engine block.

Align ream

Machining or hand process which enlarges the inside diameter of bushings to the correct size.

Alkaline battery

A storage battery which uses an alkaline electrolyte (dilute potassium hydroxide).

Alkaline degreasing

A process of removing an oily or greasy substance with the use of an alkaline solution. Often used in preparing a surface for painting.

All-alloy engine

An engine which uses a light alloy for the block, crankcase, sump, and cylinder head.

All-aluminum body

A body shell which is mostly made of aluminum.

Allan valve

Once popular slide-valve design with an internal passage designed to reduce valve travel and wear.

Allard

A vehicle brand of which the 1946-56 Series J2, K2, K3 models are milestone cars.

All electronic ignition

See	breakerless

All-electronic ignition

See	breakerless

Allen key

See	Allen wrench

Allen screw

A fastening device (either a wood screw type or bolt threads) with a recessed hexagon hole in the head. Also called a hex hole screw..

All-enveloping body

A modern passenger car body style in which the fenders, headlamps, and radiator grille are one smooth body line. It contrasts with the style before World War II where the fenders and headlights were separate from the main body.

Allen wrench

An rod with six sides and often L-shaped. Used to remove certain screws and fastenings, especially set screws. Sometimes called "hex wrenches" or "Allen key."

Alligator

A colloquial term for a large piece of a tire on the road.

Alligator clip

A small spring clip which is "X-shaped." As you squeeze the two "legs" of the clip, the other two jaws (usually serrated) open. Used to make temporary electrical connections. Larger ones are used at the ends of jumper cables. The British call it a "crocodile clip."

All-insulated switch

See	shockproof switch

All-out braking

A situation where the driver uses the maximum braking effort possible. Although this seems to be the best way to stop a vehicle, in fact it may not because there may be the tendency to swerve or the brakes may overheat and lose effectiveness. It is better to pump the brakes (if ABS is not available) to control steering and get maximum braking.

Allowance

See	mileage allowance

Allowances

Fuel reserves, usually specified as time factors under certain conditions, as distance plus descent, or as a percentage (by weight or volume) of the cruising fuel for a given stage.

Alloy

A mixture of two or more elements, especially where one is aluminum.

Also see
aluminum alloy antimony alloys eutectic alloy minilite alloy wheel polymer alloy zinc alloy

Alloy cast-iron

Cast-iron containing alloying elements in addition to carbon and the normal low levels of manganese and silicon, usually some combination of nickel, chromium, copper, and molybdenum. These elements may be added to increase the strength of ordinary irons, to facilitate heat treatment, or to obtain martensitic, austenitic, or ferritic irons.

Alloy engine

See	all-alloy engine

Alloying

[1] The process of making an alloy

[2] The addition of one or more elements to a pure metal to alter the pure metal's properties such as strength, elongation, weight reduction, etc.

Alloy piston

A piston made primarily of aluminum.

Alloys

Colloquial term for alloy wheels.

Alloy steel

[1] A steel to which elements not present in carbon steel have been added, or in which the content of manganese or silicon is increased above that in carbon steel.

[2] Molybdenum alloy steel used in bicycle frames.

Also see
high-speed steel nickel steel stainless steel

Alloy wheel

A generic term used to describe any non-steel road wheel. The usual alloys are either aluminum or magnesium; the latter material led to the common usage of the term "mag wheel," often referring to any non-steel wheel.

Also see
minilite alloy wheel three-piece alloy wheel two-piece alloy wheel two-piece forged alloy wheel

All-steel body

A vehicle body shell which is made entirely of steel rather than one with a wooden frame with steel panels or steel frame with aluminum panels.

All terrain

For use on any kind of ground surface (not on lakes or ocean, though).

All terrain bike

(ATB) A bicycle with straight handlebars, sturdy fat tires, and wide-range gearing designed for off-road use. Also called mountain bike.

All-terrain bike

(ATB) A bicycle with straight handlebars, sturdy fat tires, and wide-range gearing designed for off-road use. Also called mountain bike.

All terrain tire

A tire which has a number of lugs or knobs used to propel the vehicle over rough surfaces.

All terrain vehicle

A vehicle used in rough surface conditions. Also called off-road vehicle..

Allure libre

A self-paced long-distance bicycle ride as promoted by the Audax Club Parisien, the Randonneurs Mondiaux, and the Randonneurs USA. You can ride at your own pace so long as you finish within the time limit. This is not a race where riders are recognized for finishing ahead of other riders. The important thing is to finish the ride.

All-weather tire

A tire that can be used on roads that are bare or covered with rain, snow, or ice.

All wheel drive

See	all-wheel drive

All-wheel drive

(AWD) A variation of four-wheel drive ( 4WD) designed to improve on-road traction in unfavorable road conditions or for ultra high performance driving. All-Wheel Drive ( AWD) reduces wheel slippage and provides greater driver control over the vehicle. AWD usually does not require the driver to actively engage the system and does not have a low range. AWD automatically splits engine torque between the front and rear wheels as needed. All-Wheel Drive is generally an on-road system and is not designed for off-road use.

All-wheel steering

See	four-wheel steering

Alpine gearing

A gearing system in which a shift between chainwheels on a bicycle is equivalent to one-and-a-half shifts on the freewheel.

Alteration

See	load alteration effect

Alteration effect

See	load alteration effect

Alternating current

( AC) An electric current that first flows one way in the circuit and then the other. This is the type used in homes. It contrasts with direct current.

Alternator

( ALT) A device which produces alternating current ( AC) by converting the engine's turning (mechanical) energy into alternating electrical current at all engine speeds. The AC must be rectified (converted from AC to dc##) before reaching the vehicle's electrical system. The alternator is driven by a belt at the front of the engine. Alternators replaced the direct-current (dc##) generators used up to the 1960's because they were less efficient especially at idle. The electrically demanding options like air conditioning forced the use of alternators over generators.

Altima

A model of automobile manufactured by Nissan in Japan

.
Click for books on Altima

Altimeter

[1] An instrument to reveal the height (or barometric pressure) above sea level.

[2] An aneroid barometer used for measuring altitude by the decrease in atmospheric pressure with height. The dial of the instrument is graduated to read the altitude directly in feet or meters, the zero being set to ground or aerodrome level.

Also see
encoding altimeter radio altimeter recording altimeter

Altitude

[1] The height in feet or meters above sea level. For precision in determining the performance of an aircraft, this must be corrected for the deviation of the meteorological conditions from that of the International Standard Atmosphere.

[2] The angular distance of a heavenly body measured on that great circle which passes, perpendicular to the plane of the horizon, through the body and through the zenith. It is measured positively from the horizon to the zenith, from 0° to 90°.

[3] The line through the vertex of a geometrical figure or solid perpendicular to its base.

[4] The length of the line of definition #3.

Also see
cabin altitude pressure altitude

Altitude compensation system

A barometric switch and solenoid used to provide better drivability over 4000 feet (1200 meters) above sea level.

Altitude compensator

See	aneroid altitude compensator

Altitude valve

A manually or automatically operated valve fitted to the carburetor of an aero-engine for correcting the mixture strength as air density falls with altitude.

Alumina beads

Tiny beads of alumina used in some catalytic converters.

Aluminium

British spelling for aluminum.

Aluminum

(Al or Alum) A silver-white metal which is used in cars because of its lightness. In pure form, it does not have the strength of the same size of iron. Thus vehicle manufacturers use aluminum in an alloy form to produce body panels, wheels, engine blocks, transmission housings, differential housings, and even frames. British spelling adds an "i" near the end of the word "aluminium" and pronounces it al-you-MIN-ee-um instead of ah-LOO-min-um.

Also see
cast aluminum

Aluminum alloy

A metal which is formed from aluminum and another metal.

Aluminum body

See	all-aluminum body

Aluminum oxide

A metallic abrasive used to manufacture sandpaper and sanding discs.

Aluminum wheel

See	alloy wheel

Aluminized

Something that is coated with aluminum or aluminum paint.

Aluminizing

See	hot-dip aluminizing

Alvis

A vehicle brand of which the Speed 20, 25, and 4.3 litre models for 1925-48 are classic cars.

Acronym for amplitude modulation.

Ambient

Surrounding on all sides.

Ambient air

Air outside and surrounding the vehicle.

Ambient air temperature

The temperature of the surrounding air.

Ambient noise

[1] Random uncontrolled and irreducible noise at a location, or in a valve or circuit.

[2] The noise existing in the passenger compartment or any other environment.

Ambient sensor

A device which samples and detects changes in the temperature of the ambient air.

Ambient switch

An outside air temperature sensing switch which prevents operation of the compressor and the recirculating air mode below an outside temperature of 40°F.

Ambient temperature

The surrounding air temperature. The temperature of fluid (usually air) which surrounds object on all sides.

Ambient temperature switch

A control device in an air conditioning system which delays the compressor action when the outside temperature is low.

Ambiophony

Technique of sound reproduction which creates an illusion to the listener of being in a very large room.

Ambulance

A vehicle designed for carrying sick or injured people.

AMC

Acronym for "American Motors Corp" an organization which merged with Chrysler Corporation.

Click for books on AMC

American Automobile Labelling Act

(AALA) regulations requiring vehicle manufacturers to include content information on vehicle labels for cars and trucks for sale in the U.S. after October 1, 1994.

American Free Trade

See	North American Free Trade Agreement

American Free Trade Agreement

See	North American Free Trade Agreement

American Industrial Classification

See	North American Industrial Classification System

American Industrial Classification System

See	North American Industrial Classification System

American Motors

A vehicle brand of which the 1968-70 AMX models are milestone cars.

American produced

See	North American produced

American Society for Testing Materials

(ASTM) Society for developing and publishing agreed standards.

American standard pipe thread

Type of screw thread commonly used on pipe and fittings to assure a tight seal.

American Standard Wire Gauge

See	Brown and Sharpe Wire Gauge

American water turbine

See	mixed-flow water turbine

AM/FM

A radio capable of receiving amplitude modulation ( AM) and frequency modulation ( FM) signals.

AMIA

Acronym for "Asocicion Mexicana de la Industria Automotriz".

Amidship

The middle portion of a ship or car.

Amilcar

A vehicle brand of which the 1925-1948 Supercharged Sports models with required application are classic cars.

Ammeter

An electric instrument used to measure the rate of electrical current flow in amperes.

Ammonia

Chemical combination of nitrogen and hydrogen (NH₃). Ammonia refrigerant is identified as R-117.

Amp

Uncommon abbreviation for "ampere." It is preferred to use A.

Amperage

The strength of an electric current in amperes. Electron or current flow of one coulomb per second past a given point in circuit.

Amperage rating

The strength of an electric current in amperes.

Ampere

[1] ( A) A unit of measurement used in expressing the rate of electrical current flow in a circuit. It is determined by dividing the voltage by the resistance.

[2] A unit of electric current equivalent to flow of one coulomb per second

[3] That current which, if maintained in two parallel conductors of infinite length, of negligible cross-section, and placed one meter apart in vacuum, would produce between the conductors a force equal to 2x10^-7Nm^-1 .

Also see
absolute ampere

Ampere-hour

[1] Measurement of the ability of a battery to deliver a stated amount of current for a stated period of time. The higher the amp/hr. rating, the more powerful the battery.

[2] Unit of charge equal to 3600 coulombs or 1 ampere flowing for one hour.

Ampere hour capacity

A measurement of storage battery ability to deliver a specified current over a specified length of time.

Ampere-hour efficiency

In an accumulator, the ratio of the ampere-hour output during discharge to the ampere-hour input during charge.

Ampere-hour meter

( Ahm) A meter designed to record the product of current and time (ampere-hours) for a given circuit or passing at a given point. If the voltage is constant, the meter can be calibrated as an energy (kilowatt-hour) meter.

Ampère's law

The relation between the magnetizing field H around a conductor, length l, carrying a current i, given by the formula

Ampere-turns

See	back ampere-turns

Ampère's rule

Rule giving the direction of the magnetic field associated with a current. If the conductor is grasped with the right hand, the thumb pointing in the direction of the current, the fingers will curl around the conductor in the direction of the field. Also called right-hand rule.

Ampère's theory of magnetization

A theory based on the assumption that the magnetic property of a magnet is due to currents circulating in the molecules of the magnet.

Ampere-turn

(At) SI unit of magneto-motive force, which drives flux through magnetic circuits, arising from one ampere flowing around one turn of a conductor.

Ampere-turn amplification, gain

Ratio of the load ampere-turns to the control ampere-turns in a magnetic amplifier..

Ampere turns

Term used to measure magnetic force. Represents product of amperes times number of turns in coil of electromagnet.

Ampere-turns per meter

SI unit of magnetizing force, magnetic field intensity.

Amp/hr. rating

Measurement of the ability of a battery to deliver a stated amount of current for a stated period of time. The higher the amp/hr. rating, the more powerful the battery.

Amplifier

A device used to increase the electron flow in an electric or vacuum circuit. It produce a greater electrical signal such as the radio signal. Most automobile radios have a built-in amplifier; but a few have a separate amplifier which is sometimes located in the trunk.

Also see
acoustic amplifier audio-frequency amplifier balanced amplifier booster amplifier ignition amplifier

Amplitude modulation

(AM) A type of radio wave in which the amplitude changes rather than the frequency.

Also see
frequency modulation

AMPS

Abbreviation for advanced mobile phone system.

Amps

See	cold cranking amps

Amputee spinner

A device which is attached to a steering wheel to allow disabled people to steer a vehicle.

AMS

Acronym for "air management system."

AMSL

Abbreviation for above mean sea level.

AMVIR

Acronym for "Association of Motor Vehicle Importers Representatives" (Greece).

Anaerobic sealer

A substance used to prevent bolts and screws from loosening up and backing out. Anaerobic sealers do not require oxygen for activation. The Loctite® brand is the most widely used anaerobic sealer.

Analog

A display which uses a dial rather than a read-out of numbers (digital). British spelling is analogue.

Analog clock

The traditional clock with rotating hands. Contrast with digital clock.

Analog cluster

An instrument panel display using dials. Opposite to electronic cluster.

Analog filter

Filter suitable for use with analog signals, i.e., those which are continuous with time. Contrast with digital filter.

Analog speedometer

A speedometer which shows the speed by a needle on the dial of a gauge. It contrasts with a digital speedometer

Analogue

British spelling of analog.

Analogue cluster

See	analog cluster

Analysis

See	Fe analysis finite-element analysis

Analyzer

A device for evaluating something.

Also see
engine analyzer exhaust-gas analyzer exhaust gas analyzer Ndir analyzer non-dispersive infrared analyzer

Anatomic saddle

A bicycle seat that is designed with cut out sections or bumps to accommodate your ischial tuberosities (i.e., sit-down bones).

ANC

Acronym for "at no extra cost."

Anchor

[1] A mounting point on the vehicle frame or unibody for a non-structural but stressed component, such as a seat or seat belt.

[2] The stationary portion of a leading/trailing drum brake on which the heels of the brake shoes ride.

Also see
belt anchor belt anchor brake anchor

Anchorage

The point where something is attached -- such as where the seat-belt is attached to the frame.

Also see
belt anchorage seat belt anchorage

Anchor bolt

[1] A bolt used to secure frameworks, stanchion bases, etc. to piers or foundations, and having usually a large plate washer built into the latter as anchorage

[2] The bolt which goes through a bracket to secure something. British term is "through bolt."

Anchor clamp

A fitting attached to the overhead contact wire of a tramway or railway to support the wire, and also to take the longitudinal tension and prevent movement of the wire in a direction parallel to the track.

Anchor gate

A heavy gate, such as a canal lock gate, which is supported at its upper bearing by an anchorage in the masonry such as an anchor bolt.

Anchor end

The end of a brake shoe that's attached to or positioned against a fixed point on the backing plate.

Anchor pin

The stationary portion of a duo-servo drum brake on which the tops of the brake shoes rest. The secondary shoe bears against the anchor pin when the brakes are applied and the vehicle is moving forward. Conversely, when the vehicle is backing up and the brakes are applied, the primary shoe bears against it.

Anchor plate

The stationary portion of a leading/trailing drum brake on which the heels of the brake shoes ride.

Also see
caliper mounting bracket

Anchor ring

See	toroid torus

Ancien

A male veteran bicycle rider who has completed a 1200 kilometer randonnée.

Ancienne

A female veteran bicycle rider who has completed a 1200 kilometer randonnée.

Ancillaries

The various components attached to the main part of the engine and driven by the engine itself -- such as the alternator, generator, power steering pump, supercharger, fuel pump, and water pump.

Anemometer

Instrument for measuring the rate of airflow or motion.

Aneroid altitude compensator

A bellows device, installed integrally with the APT system on some post-1975 Rochester Quadrajet carburetors, that automatically compensates for changes in altitude by raising or lowering the primary metering rods, thus richening or leaning out the air/fuel mixture in accordance with changes in air pressure.

Aneroid-type thermostat

An older style thermostat located in the engine coolant system. It has a metal expandable bulb partially filled with acetone, alcohol, or another volatile liquid. As the coolant reaches operating temperature, the liquid in the bulb will boil and expand the bulb, closing the valve to allow coolant to the radiator.

ANFAC

Acronym for "Asociacion Espanola de Fabricantes de Automoviles y Camiones" (Spain).

ANFAVEA

Acronym for " Associação Nacional de Veículos Automotores" (Brazil).

ANFIA

Acronym for "Associazione Nazionale Fra Industrie Automobilistiche" (Italy).

Angels

Radar echoes from an invisible and sometimes undefined origin. High-flying birds, insect swarms, and certain atmospheric conditions can be responsible.

Angle

See	ackermann angle approach angle attack angle azimuth angle blade angle bragg angle bunching angle brewster angle	cam angle caster angle departure angle dwell dwell angle front triangle heading angle ignition angle	included angle lock angle offset angle opening angle rake ramp-over angle rear triangle roll angle	shallow angle slip angle spark angle spark ignition angle steep angle steering angle steering knuckle angle swivel angle	thread angle tire deviation angle tire slip angle toe-in angle triangle-split system valve angle yaw angle

Angle bar

See	angle iron

Angle bearing

A shaft-bearing in which the joint between base and cap is not perpendicular to the direction of the load, but is set at an angle.

Angle block

A cylinder block that doesn't have a deck at 90 degrees to the cylinders

A small wooden block used in woodwork to make joints, esp. right-angle joints, more rigid.

Angle bracket

[1] A bracket projecting from the corner of a building beneath the eaves, and not at right-angles to the face of the wall.

[2] A bracket consisting of two sides set at right angles, often stiffened by a gusset. Also called gallows bracket.

Angled deck

British term for canted deck.

Angledozer

A bulldozer with a blade able to be set in such a way to push material to the side of the road. Usually called a grader or motor grader.

Angle elevation

The vertical angle measured above the horizontal, from the surveyor's instrument to the point observed.

Angle grinder

A power tool (driven by electricity or compressed air) which has abrasive discs. The tool helps to remove old paint or rough metal surface

Angle iron

Mild steel bar rolled to an L-shaped cross-section, used in structural work. Legs may be equal or unequal and leg lengths up to 800 mm are available. Also called angle, angle bar, angle steel, and L-iron.

Angle-nose pliers

A pair of pliers with long jaws that are bent at right angles to aid in gripping something which cannot be reached with regular pliers.

Angle of advance

[1] The angle in excess of 90° by which the eccentric throw of a steam-engine valve gear is in advance of the crank.

[2] The angle between the position of ignition and outer dead center in a spark-ignition engine, optimizes combustion of the fuel.

Angle of attack

The angle between the chord line of an airfoil and the relative airflow. Also called (in error) angle of incidence.

Angle of contact

The angle subtended at the center of a pulley by that part of the rim in contact with the driving belt.

Angle of lock

The angle between the line through the center of the wheel seen from above when turning a corner and the same line when going straight.

Angle parking

A system of parking on the side of the street where the car is about 45 degrees from parallel with the edge of the street. The British term is "echelon parking"

Angle screwdriver

A tool that is shaped like the letter "L" and has a blade at either end.

Angle steel

See	angle iron

Angle stone

See	quoin

Angle valve

Type of globe valve design, having pipe openings at right angles to each other. Usually, one opening is on.

Angular motion

See	rotation

Angular thread

See	vee thread

Angular vibration

Side to side movement or shimmy of a tire.

Also see
dynamic balance

Anneal

To remove hardness from metal by heating, usually to a red color, then allowing it to cool slowly. Unlike steel, copper is annealed by heating, and then plunging it into cold water. It is the reverse of hardening.

Annealing

Process of heat treating metal to get desired properties of softness and ductility (easily formed in to a new shape). For example heating and slow cooling of a piece of iron.

Also see
back annealing box annealing bright annealing

Annular

Something in the form of a ring.

Annular ball bearing

A ball bearing with a non-adjustable inner and outer race or races.

Annular combustion chamber

A gas turbine combustion chamber in which the perforated flame tube forms a continuous annulus within a cylindrical outer casing.

Annular gap

Something in a circular gap.

Annular gear

A round gear with teeth cut on the outside for engagement with a pinion. Usually shrunk fit on to a mating diameter, e.g., starter ring on automobile flywheel.

Annulus

A hollow gear which is in the form of a ring with internal teeth.

Also see
epicyclic gearbox

Anode

In an electrical circuit it is the positive pole. It is that part of an electrical circuit to which electrons are flowing.

Also see
sacrificial anode soluble anode

Anodize

By electrolytic action, this is the process of coating or plating a metal (usually aluminum) with a thin protective film or material such as chrome. It is sometimes applied with colored dye.

Anodized

An electroplating process commonly performed on aluminum parts, which forms a thin protective film on the surface of the metal. Anodizing is sometimes accompanied by the use of a colored dye, which gives a lustrous colored finish to the aluminum parts.

Anodizing

The process by which a hard, non-corroding oxide layer is deposited on aluminum.

Also see
color anodizing hard anodizing integral color anodizing

Anodizing bath

A tub in which the anodizing process is performed.

Anodizing tank

A tub in which the anodizing process is performed.

ANS

Acronym for "anti-noise system."

ANSI

Acronym for "American National Standards Institute."

Ant

See	p. ant

Antagonizing screws

See	clip screws

Antechamber

A small auxiliary combustion-chamber, used in some compression-ignition engines, in which partial combustion of the fuel is used to force the burning mixture into the cylinder, so promoting more perfect combustion.

Antenna

A device which pulls in radio reception. A power antenna automatically rises when the radio is turned on and lowers when it is shut off. Some cars had the antenna wires imbedded in the windshield. Also called aerial.

Also see
adc##ock antenna alford antenna antifading antenna aperiodic antenna artificial antenna balancing antenna beam antenna beavertail antenna beverage antenna power antenna whip antenna

Antenna changeover switch

Switch used for transferring an antenna from the transmitting to the receiving equipment, and vice versa, protecting the receiver.

Antenna downlead

Wire running from the elevated part or conductor of an antenna down to the transmitting or receiving equipment.

Antenna load

See	dummy load

Antibackfire valve

See	anti-backfire valve

Anti-backfire valve

( Anti-BFV) Valve used in air injection reaction ( exhaust emission control) system to prevent backfiring during the period immediately following sudden deceleration by diverting the air coming from the air pump away from the exhaust ports. Otherwise the exhaust gases which contain unburned gasoline could mix with fresh air and cause unwanted backfiring.

Also see
air bypass valve

Anti-BFV

Acronym for "anti-backfire valve."

Anti-chip coating

A resilient coat of "paint" between the primer and the top coat to protect the body shell from chipping damage caused by gravel or stones.

Anti-corrosion

A substance used to protect against rust.

Also see
Nordic Anti-Corrosion Code

Anti-Corrosion Code

See	Nordic Anti-Corrosion Code

Anti-corrosion warranty

Manufacturers usually state that all body sheet metal components are warranted against rust-through corrosion for 6 years or 160,000 kilometers (100,000 miles), whichever comes first.

Anti-corrosive

That which prevents or limits corrosion.

Anti-dazzle mirror

A mirror that can be set to reduce the glare of the lights from a vehicle following your vehicle.

Also see
dimming mirror

Anti-dieseling solenoid

See	idle-stop solenoid

Antidive

See	anti-dive system

Anti-dive

See	anti-dive system

Anti-dive system

A dive is the action of the front of the vehicle to point downward during braking. The suspension in cars is designed to remove this tendency.

Anti-drum compound

A sticky material which is applied to the inside of panels to reduce the noise caused by vibration or "drumming."

Antifouling composition

A substance applied in paint form to ships' bottoms and structures subject to the action of sea water, to discourage marine growths.

Antifreeze

A chemical (usually ethylene glycol) added to the cooling system to prevent the coolant from freezing in cold weather. It also inhibits the formation of rust and other deposits which may clog the radiator and other cooling passageways. Its resistance to freezing is better with a mix of 5050 with water than 100% antifreeze.

Anti-friction bearing

See	antifriction bearing

Antifriction bearing

A bearing containing rollers, needles, or balls plus an inner and outer race. The bearing is designed to roll instead of slide thus minimizing friction between two moving parts. To avoid disintegration, the bearing must use lubrication (i.e., wet friction)

Anti-friction metal

See	white metal

Anti-g

Resistant to the effects of high acceleration, esp. of an astronaut's equipment.

Anti-g suit

A close-fitting garment covering the legs and abdomen. When inflated, it equalizes the pressure especially around the head and heart during high-speed maneuvers. Colloquially, g-suit.

Anti-knock additive

See	anti-knock agent

Antiknock agent

See	anti-knock agent

Anti-knock agent

A substance like tetraethyl lead which is added to gasoline to raise the octane number and reduce the gasoline's tendency to detonate, knock, or ping. In unleaded gasoline, tetraethyl lead is not used because of its environmental danger.

Anti-knock agents

See	anti-knock agent

Anti-knock index

The measure of the anti-knock properties of a brand and type of gasoline. It is defined as half the sum of the research octane number ( RON) and motor octane number ( MON).

Antiknock substances

Substances like lead (IV) ethyl added to fuel to lessen its tendency to detonate or "knock" in an engine.

Antiknock value

The relative immunity of a volatile liquid fuel from detonation in a gasoline engine as compared with some standard fuel.

Also see
knock rating octane number

Antilift

See	anti-lift

Anti-lift

Lift is the action of the rear end of the vehicle to rise during braking. The suspension in cars is designed to remove this tendency.

Antilock brake

( ABS)

See	anti-lock brake system

Anti-lock brake

( ABS)

See	anti-lock brake system

Anti-lock brake controller

CAB Chrysler Corporation's term for the electronic control unit.

Anti-lock brake system

( ABS) Sometimes called "anti-skid brakes." A device which senses that one or more of the wheels are locking up during braking. It monitors the rotational speeds of the wheels and reduces hydraulic pressure to any wheel it senses locking up. It is controlled by both mechanical and electronic components. When you apply the brakes, the ABS will regulate the flow of brake fluid being delivered to the brake calipers. It must be remembered that a wheel cannot be steered unless it is rolling; so if the wheel is locked up, there is no steering control. By the use of electronic computers, the brakes rapidly alternate (at a rate of 30 times per second) from full pressure to full release. This process will also alternate from the left-front wheel and the right-rear wheel and switch to the right-front wheel and left-rear wheel. In this way both maximum braking and maximum steering control is allowed during braking. Before the advent of ABS, drivers were advised to pump the brakes to maintain the same effect. However, the human foot cannot pump the brakes faster than the computer control. Also, steady application of the brakes without ABS may cause brake failure ( brake fade) because of the excess heat. Never pump the brakes if you have ABS. When you firmly apply the brakes with ABS, you may feel a pulsing sensation and hear a banging noise. The abbreviation ABS comes from the German anti blockier system.

Anti-lock braking system

See	anti-lock brake system

Anti-noise

See	anti-noise system

Anti-noise system

( ANS) A noise counteraction system. This is a sophisticated system which has a number of small microphones placed around the vehicle to detect driving noises. A computer microprocessor analyzes these noises and generates matching counter-frequencies which are sent to small speakers located in the passenger compartment. In this way the road noises are cancelled or erased.

Antipercolation valve

See	anti-percolation valve

Anti-percolation valve

A device for venting vapors from the main discharge tube, or the well, of a carburetor. The vented vapors are not released into the atmosphere, but rerouted into an evaporative emission canister where they are stored until the next time the vehicle is started. Thus it provides a richer mixture needed for starting.

Also see
percolation

Anti-rattle spring

A component in disc brakes shaped like the letter "X" and made of spring steel. It applies radial pressure to the brake pads to prevent rattling. Also called spreader spring.

Antiroll bar

See	anti-roll bar

Anti-roll bar

Sometimes called the "anti-sway bar," "stabilizer bar," or even (incorrectly) "roll-bar." It is usually a round bar which connects the left wheel suspension assembly with the right side. It may be found at the front and/or rear. Its main function is to keep both wheels rolling at the same rate when meeting bumps; but it also affects handling. A front anti-roll bar increases understeer and a rear bar increases oversteer.

Antiroll device

See	brake anti-roll device

Anti-roll device

See	brake anti-roll device

Anti-rust treatment

See	rustproofing

Antisag bar

A vertical rod connecting the main tie of a roof truss to the ridge to support it against sagging under its own weight.

Antiscuffing

The ability of a precision insert bearing to resist scuffing or scratching the shaft journal in the event that the oil surface skin is destroyed.

Anti-siphon bleeds

Small holes drilled into the cluster to prevent main-system fuel from continuing to flow when the throttle is closed, stopping airflow through the carburetor.

Antiskid

See	anti-skid

Anti-skid

( ASBS) A computer controlled automotive device which senses when one or more of the wheels are locking up during braking. It eases up on the amount of hydraulic pressure to that wheel. It must be remembered that a wheel cannot be steered unless it is rolling; so if the wheel is locked up, there is no steering control. By the use of electronic computers, the brakes rapidly alternate from full power to none so that both maximum braking and maximum steering control is allowed. If you jam on the brakes, you will feel a pulsing sensation. Sometimes called "anti-lock brakes."

Antismog device

A special part or system designed to reduce or eliminate emission of noxious gases from exhaust of engine.

Antisolar glass

Glass which absorbs heat from sunshine and reduces glare, but transmits most of the light.

Antisound

Sound signal with same amplitude but opposite phase of some unwanted sound signal so that both signals cancel each other when superimposed. Used in active control.

Anti-spin regulation

( ASR) The control or prevention of wheelspin under power, normally by means of electronic sensing and in conjunction with anti-lock brakes.

Anti-spin regulation traction control system

( ASC) The system which prevents wheelspin.

Also see
anti-spin regulation

Anti-spray flap

See	mudflap

Antisquat

See	anti-squat system

Anti-squat

See	anti-squat system

Anti-squat system

Squat is the action of the rear end of the vehicle to point downward during hard acceleration. The suspension in cars is designed to remove this tendency. Contrasts with anti-dive system.

Anti-squeal shim

A shim (metal plate) placed behind the brake piston or the brake pad to reduce noise when the brakes are applied.

Anti-stall dashpot

A diaphragm unit mounted on the carburetor that allows air to escape slowly from its vacuum chamber to prevent throttle plate(s) in the carburetor from closing too suddenly--and stalling the engine--during deceleration.

Antisurge valve

A valve for bleeding off surplus compressor air to suppress the unstable airflow due to surge in a gas turbine engine.

Anti-sway bar

See	anti-roll bar

Anti-theft system

Any device (mechanical or electrical) which tends to reduce the theft of a vehicle. It may involve an alarm system, ignition lockouts, steering locks, steering wheel locks, transmission locks, and/or wheel locks.

Anti-tipper

An arm, usually with a small wheel attached at the outer end, which is secured to the back of a wheelchair to prevent the chair from falling on its back and thereby injuring the patient.

Antitippers

See	anti-tipper

Anti-vibration mounting

[1] Because the engine, transmission, differential, and other components tend to vibrate when in motion, noise increases and there is possible wear at the points of contact with the frame members. Rubber blocks are used to cushion the vibration at the mounting points.

[2] Rubber springs designed to absorb vibrations from engines, etc. Care needed in design and materials selection to match vibration frequency with main damping peak of elastomer.

A-panel

The side panel used to fill the gap between the rear edge of the front fender and the front edge of the doors.

Ape hangers

A term coined at the height of the custom-bike movement to describe tall handlebars that forced the rider to reach skyward to grasp the controls, making the rider adopt an ape-like posture.

Aperture panel

A large side panel of a vehicle making up the rear fender, door frame, and side window frame.

Also see
side aperture panel sunroof aperture panel

Apex

The top of a triangle. In racing, it is the point or area closest to the inner corner.

Apex seal

A wedge shaped device found on the tips of the triangular rotor in rotary (Wankel) engines. Its purpose is to prevent the escape of compressed gas or combustion gases. It may also release engine heat.

API

Acronym for "American Petroleum Institute," the organization that classifies oil.

APIA

Acronym for "Association of Automotive Manufacturers and Importers" (Romania).

API scale

Abbreviation for American Petroleum Institute scale. Scale of relative density, similar to Baumé scale. Degrees API=(141.5/s)-131s, where s is the relative density of the oil against water at 15°C.

A pillar

See	A-post

A-pillar

When you look at the side of a car, the pillar that is attached to the windshield and supports the roof is called the "A-post" or "A-pillar." There are two to each car. Generally the middle post is the B-post and the back post is the C-post.

Apollo

A vehicle brand of which the 1963-66 models are milestone cars.

A post

See	A-post

A-post

When you look at the side of a car, the post that is attached to the windshield and supports the roof is called the "A-post" or "A-pillar." There are two to each car. Generally the middle post is the B-post and the back post is the C-post.

Apparatus

See	air-cooled apparatus Beckmann apparatus

Appendages

Structures extending beyond the main hull. They include items like shafting, rudder, bossing, struts, and bilge keels.

Apple paint

See	candy apple paint

Appliance

A British term for a fire engine.

Applicator

A tool for putting something on something else, e.g., a spreader or brush.

Also see
heating inductor

Applied stress

The stress induced in a member under load.

Appliqué

(appliqué) A sticker or decal which is applied to the body panel of a vehicle.

Apply

To put something on something else.

Approach

A secondary road leading up to a highway.

See	arc of approach

Approach angle

The most sharply angled incline the vehicle can make without its front scraping the ground. Measured in degrees, it's the angle formed on one side by the horizontal axis, and on the other by a straight line connecting the forward edge of the front tire and the most prominent front-end feature extending beyond that line -- the bumper, fog lamps, tow hook, etc.

Approval certificate

See	type approval certificate

Aprilia

A well-regarded Italian motorcycle manufacturer, known for 250 GP race bikes that are tiny and lightweight.

Apron

[1] The paved area directly below the racing surface that separates the track from the infield.

[2] The panel under the vehicle's doors or the panel acting as an air dam at the front of a vehicle.

[3] A kick panel.

[4] A firm surface of concrete or "tarmac" laid down adjacent to aerodrome buildings to facilitate the movement, loading and unloading of aircraft.

Also see
fender splash apron front apron rear apron

APT

Acronym for "adjustable part throttle"

APU

Acronym for auxiliary power unit

AQL

Acronym for "acceptable quality level."

Aquaplaning

Also called hydroplaning. A dangerous tendency for a tire to ride on a thin film of water, thus creating a loss of driver control until tire contact with the road surface returns.

Aquatread

A tread pattern of a tire designed to dissipate water lying on the road and provide good traction in the rain.

Arbor

[1] A rotating shaft in a lathe or drill.

[2] Cylindrical or conical shaft on which a cutting tool or part to be machined is mounted.

[3] The axis or shaft upon which a rotatable part is mounted the shaft upon which a gear or wheel is mounted.

Also see
mandrel

Arc

[1] The discharge of electric current across a gap of two electrodes. The term given to the flow of electricity through a gaseous space or air gap.

[2] A welding term referring to the flow of electricity through the air which produces high temperatures.

Also see
arc welding shielded arc short arc spray arc track arc

ARC

[1] Acronym for Aeronautical Research Council in the UK.

[2] Acronym for Ames Research Center in the USA

Arc blow

A welding term referring to the tendency for an arc to wander or whip from its normal course during arc welding. It is caused by magnetic changes.

Arc crater

[1] Depression formed in electrodes between which an electric arc has been maintained.

[2] In arc welding, the depression which occurs in the weld metal.

Arc cutting

A welding term referring to making a kerf in a metal using the energy of an electric arc.

Arch

See
fender arch flared wheel arch wheel arch

Arch extension

See	wheel arch extension

Arch protector

See	wheel arch protector

Arcing

[1] The action of electricity when it leaps the gap between two electrodes. Usually causes premature wear of breaker points.

[2] A faulty paint spraying technique where the spray gun is not moved along the panel surface at a uniform distance. Instead it is moved toward the panel when starting and moved away toward the end of the panel. The result of this technique is an uneven application of paint.

[3] A process where the brake shoes are ground to the proper curvature for the drums they are to be used with. Modern brake shoes are pre-arced.

Arc of approach

The arc on the pitch circle of a gearwheel over which two teeth are in contact while approaching the pitch point

Arc of contact

The arc on the pitch circle of a gearwheel over which two teeth are in contact.

Arc of recess

The arc on the pitch circle of a gearwheel over which two teeth are in contact while receding from the pitch point.

Arc process

See	bredig's arc process

Arc-suppression coil

See	Petersen coil

Arc suppressor

A device for automatically grounding the neutral point of an insulated-neutral transmission or distribution line if an arc to ground occurs. Also called arcing-ground suppressor

Arc welding

Welding by using an electric current to melt both the metal to be welded and the welding rod or electrode that is being added.

Also see
atomic arc welding automatic arc welding inert arc welding pulse arc welding

Arm

A part attached to or projecting from something.

Also see
a-arm a arm actuator arm adjustable rocker arm ball joint rocker arm breaker arm branch check arm brush-holder arm contact arm	control arm crankarm door check arm drop arm flex arm suspension forked rocker arm high lift rocker arm idler arm knuckle arm lateral arm	leading arm long and short arm suspension pitman arm radius arm rocker arm rocker arm cover rocker arm shaft rotor arm semi-trailing arm stay	steering arm steering gear arm steering knuckle arm throttle arm tie rod arm torque arm track control arm trailing arm transverse arm

Armature

[1] In a relay, regulator, horn, etc., it is the movable part of the unit which indicates the presence of electric current as the agent of actuation.

[2] Piece of low-reluctance ferromagnetic material (keeper) for temporarily bridging the poles of a permanent magnet, to reduce the leakage field and preserve magnetization.

[3] In a starter or generator, it is the portion that revolves between the pole shoes, made up of wire windings of copper on an iron core or axle. When it revolves, an electric current is induced.

Also see
bar-wound armature

Armature brake

A mechanical or electrical component in a starter used to stop the armature movement after the starter motor has been switched off.

Armature end plate

The end plate of a laminated armature core. It is of sufficient mechanical strength to enable the laminations to be clamped together tightly to prevent vibration. Also called armature head

Armature head

See	armature end plate

Armature relay

A relay operated electromagnetically, thus causing the armature to be magnetically attracted.

Armature shaft

The primary shaft on which the armature is mounted in a starter or generator.

Armature winding

The complete assembly of conductors carried on the armature and connected to the commutator or to the terminals of the machine.

Arm cover

See	rocker arm cover

Armor plate

Traditionally, specially heavy alloy steel plate hardened on the surface; used for the protection of fighting vehicles and ships. There is also a form of armor plate based on aluminum alloy particularly suitable for fast moving military vehicles.

Armor-plated

Panels and glass that are extra thick to be bullet-proof.

Armour

British spelling of "armor"

Armrest

A projection upon which the occupants can rest or support their arms. Usually located on the door panel and sometimes in the center of the front seats or the center of the rear seat.

Arms

See	bracket arms control arms high lift rocker arms

Arm shaft

See	rocker arm shaft

Armstrong

A colloquial term for manual steering. Without power assist, steering will need a strong arm, thus the name.

Armstrong-Siddeley

A vehicle brand of which the 1925-1948 models with required application are classic cars.

Arm suspension

See	flex arm suspension long and short arm suspension semi-trailing arm suspension swing arm suspension

Arnolt

See	Arnolt Bristol

Arnolt Bristol

A vehicle brand of which the 1952-62 models are milestone cars.

Arrester

A device which prevents a certain action. For example, a spark arrester is a special pipe mounted in the end of the exhaust pipe which prevents any burning gasses from coming out with the possible danger of igniting any combustibles in the area (i.e., setting the forest on fire).

Also see
lightning arrester

Arrive

The finish line of a brevet or randonnée.

Articulated

Jointed. An articulated rod is made of two sections with a moveable joint which permits its shape to go from perfectly straight to right angle.

Also see
articulated bus articulated truck

Articulated bus

A large bus with an accordion-like section in the middle of the body which allows the bus to turn sharply around corners as it articulates at that part of the bus.

Articulated mounting

A term used where parts are connected by links and links are anchored to provide a double hinging action.

Articulated truck

A large truck with two sections to allow it to turn sharply around corners.

Artificial rubber

See	synthetic rubber

ASA

Formerly, abbreviation for American Standards Association. Now known as American National Standards Institute.

Asbestos

A heat resistant and non-burning fibrous mineral widely used for brake shoes, clutch linings, etc. Asbestos is a health hazard and the dust created by brake systems should never be inhaled or ingested.

Asbestos-free

Something that has no asbestos -- especially brake and clutch linings.

Asbestosis

An incurable lung disease caused by the inhalation of asbestos fibers.

ASBS

See	anti-skid braking system

ASC

See	anti-spin regulation

Ascending stroke

See	up-stroke

ASD

Acronym for automatic slip-control differential.

ASE

National Institute for Automotive Service Excellence.

ASEAN

Acronym for Association of South East Asian Nations.

Ash frame

A frame of a car made of wood from the ash tree and covered with aluminum panels.

Ashtray

A device for holding cigarette ashes.

ASIA

Acronym for "Automotive Service Industry Association."

ASME

Acronym for "American Society of Mechanical Engineers."

Aspect ratio

[1] The ratio of length to width of rectangular air grille or duct.

[2] The relationship in a tire or wheel between the distance from the rim to the tread and the tire's width (i.e., ratio of section height to section width). Thus, in a P185/80R13 tire, 80 is the aspect ratio, showing the height is 80% of the width. A lower aspect ratio describes a shorter, wider tire.

[3] In a wing, it is the relationship of its span (horizontal length) to its chord (height). Important for induced drag and range/speed characteristics. Defined as S²/A where S is the span and A is the area. Normal figure between 6 and 9, lesser values than 6 being low aspect ratio, greater than 9 high aspect ratios.

[4] Ratio of the length of a fiber or wire to its width or diameter.

[5] (AR) Ratio of the width to the height of the reproduced picture or computer screen, e.g., 4x3, often expressed with the height as unity. 1.331. Wide-screen systems have aspect ratios between 1.651 and 2.351.

[6] In a Tokamak type of fusion machine, the ratio of the major to minor radii of the torus.

Also see
ULP

Asphalt

[1] A bituminous substance found naturally in oil-bearing strata from which the volatiles have evaporated

[2] A residue in petroleum distillation

[3] A mixture of asphaltic bitumen and granite chippings, sand, or powdered limestone. Asphalt is used extensively for paving, road-making, damp-proof courses, in the manufacture of roofing felt and paints and as the raw material for certain moulded plastics.

Also see
bitumen

Aspirated

See	aspirated engine

Aspirated engine

See	naturally aspirated engine normally aspirated engine

Aspiration

The process of sucking or inhaling the air-fuel mixture into a combustion engine.

Aspirator

The air intake of a sensor.

Aspirator system

See	air aspirator system

Aspirator valve

A check valve in an air injection system.

Aspire

A model of automobile manufactured by Ford

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ASR

[1] Acronym for anti-spin regulation.

[2] Acronym for Acceleration Slip Regulation.

Assemble

The action of putting something together from a number of component parts.

Assembly

[1] The finished union of a number of parts to make a component.

[2] Construction of product from several or many components. Methods used for attachment include welding, fastening, push-fit, snap-fit, lock-fit, adhesive bonding, ultrasonic welding, etc. Many products are now designed for robotic assembly.

Also see
body assembly bearing assembly

Assembly line

The production line where a vehicle is put together from its component parts. Often one team will work on just the engine of each vehicle while another team works on another part, etc.

Assembly lube

A special lubricant used to coat parts that rub or rotate against each other during initial assembly.

Assist power steering

See	variable assist power steering

Assist steering

See	variable assist steering

Assisted

See	hydraulic assisted brakes integral-type power assisted steering power assisted brakes servo-assisted

Assisted brakes

See	hydraulic assisted brakes power assisted brakes vacuum assisted brakes

Assisted steering

See	integral-type power assisted steering

Association of South East Asian Nations

(ASEAN) An organization of states (including Brunei, Myanmar, Burma, Indonesia, Laos, Malaysia, the Philippines, Singapore, Thailand, and Vietnam) founded in 1967 to present an united front that addresses the political, economic, and strategic dynamics of the region.

Assy

Abbreviation for assembly.

Astern

A backward movement of a vessel.

ASTM

Acronym for "American Society for Testing Materials."

ASTM standards

Standards issued by the American Society of Testing Materials.

Aston-Martin

A vehicle brand of which the 1927-1939 models with application and all others from 1925-48 are classic cars.

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Aston Martin

A vehicle brand of which the 1948-63 models are milestone cars. All the DB4, DB5, DB6 from 1964-67 are milestone cars.

Asymmetric

A pattern in which one side does not correspond to the other side.

Asymmetrical

[1] A pattern in which one side does not correspond to the other side. Also called or non-symmetrical.

Asymmetrical beam

A headlight system in which one beam is of greater intensity than the other.

Asymmetrical power distribution

A system in a four-wheel vehicle in which more power is transmitted to the front wheels than the rear wheels or more to the rear wheels than the front wheels.

Asymmetrical tread

The tread of a tire which has different shapes/patterns and sizes of grooves in the same tire. Often they are divided into three distinct patterns The outside shoulder, the center zone, and the inside shoulder. The outside shoulder tread will have larger shoulder elements with very few sipes to provide increased cornering stability. The center tread zone enhances steering control. The inside shoulder tread zone provides additional traction because the shape of the tread elements, sipes and larger shoulder slots help disperse water and slush. Obviously these tires must be mounted only one way so that the outside pattern is actually on the outside of the wheel

Asymmetric rim

A wheel rim where the well is located outside the centerline of the wheel. Opposite of symmetric rim.

Asynchronous motor

See	non-synchronous motor

ATA

[1] Acronym for "American Trucking Association."

[2] Acronym for Air Transport Association

ATB

[1] Acronym for all-terrain bike. Sometimes called MTB (mountain bike), but ATB is the preferred acronym.

[2] Acronym for aeration test burner

ATC

[1] Acronym for "automatic temperature control."

[2] Acronym for air-traffic control

ATdc##

See	after top dead center

ATE

Acronym for "automatic test equipment."

ATF

See	automatic Transmission Fluid transmission fluid.

A thread

See	class A thread

Athwartship

Across the ship, at right angles to the fore-and-aft centerline.

ATM

Abbreviation for standard atmosphere.

Also see
atmospheric pressure

Atmospheric engine

Earliest form of practical steam engine, in which a partial vacuum created by stem condensation allowed atmospheric pressure to drive down the piston.

Atmospheric gas-burner system

A natural-draft burner injector, in which the momentum of the gas passing into the injector throat inspirates part of the air required for combustion.

Atomize

The process of changing liquid to minute particles or a fine spray. The extent to which a spray gun breaks up paint into a fine mist, fog, or spray.

Atomized powder

A powder produced by the dispersion of molten metal or other material by spraying under conditions such that the material breaks down into powder.

Atomizer

A device for producing a fine spray such as used on a paint spray gun.

Atomizing pressure

The pressure needed to atomize a liquid like paint.

ATR

Acronym for attenuated total reflection

Atramentizing

A corrosion protection process in which steel is coated with phosphate using a zinc phosphate solution at 90° C (194° F).

ATR tube

Abbreviation for anti-transmit-receive tube

Attachment

A fitting or accessory to be used in conjunction with a tool, such as a grinding disc for use with an electric drill.

Also see
bearing attachment inner attachment face

Attachment face

See	inner attachment face

Attack

[1] Chemical corrosion of metal.

[2] To damage something by corrosion.

Also see
angle of attack base metal attack pickling attack

Attack angle

The angle of the rear spoiler where it is most effective against lift.

Attendant parking

Parking which is left to a valet and supervised by an attendant.

Attenuated total reflection

Spectroscopic method of analyzing thin films on reflective substrates, esp. using infrared radiation.

Attenuation

[1] A reduction of noise or emission.

[2] General term for reduction in magnitude, amplitude, or intensity of a physical quantity, arising from absorption, scattering, or geometrical dispersion. The latter, arising from diminution by the inverse square law, is not generally considered as attenuation proper.

Attenuation coefficient

The coefficient which expresses energy losses of electromagnetic radiation due to both absorption and scattering in a medium. Relevant to narrow beam conditions. Also called total absorption coefficient

Attenuation compensation

The use of networks to correct for frequency-dependent attenuation, e.g., in transmission lines.

Also see
pre-emphasis

Attenuation constant

The real part of α in the relationship ρ=ρe^{- αx}, where ρ is a physical quantity, such as the amplitude of a wave propagating along a transmission path, and x is the distance along the path. The imaginary part of α is known as the phase constant. More simply, but less commonly defined by μ = αλ where μ is the attenuation and λ is wavelength, i.e., α is the attenuation per wavelength distance of propagation.

Also see
decibel neper propagation constant

Attenuation distortion

Distortion of a complex waveform resulting from the differing attenuation of each separate frequency component in the signal. This form of distortion is difficult to avoid, e.g., in transmission lines.

Attenuation of X-rays

Absorption and scattering of X-rays as they pass through an object.

Attenuator

An arrangement of fixed or variable resistive elements designed to reduce the strength of any signal (audio- or radio-frequency) without reducing appreciable distortion. Attenuators also incorporate impedance matching to the transmission lines or circuits to which they are connected, regardless of the attenuation they introduce. For lower frequency applications they may be simply variable or fixed resistances, for high frequencies they may be pieces of resistive material, introduced into transmission lines, stripline, or waveguide. Fixed attenuators are sometimes referred to as pad.

Attitude

Of an aircraft in flight, the angle made by its axes with the relative airflow; the aspect is the angle made by its axes with the ground when the aircraft is on the ground.

Attitude indicator

A gyro horizon which indicates the true attitude of the aircraft in pitch and roll throughout 360° about these axes.

Also see
heading indicator

Attracted-disk electrometer

Fundamental instrument in which potential is measured by the attraction between two oppositely charged disks.

Attrition

A process of wearing out an object by friction.

Attrition test

A test for the determination of the wear-resisting properties of stone, particularly stone for road-making. Pieces of the stone are placed in a closed cylinder, which is then rotated for a given time, after which the loss of weight due to wear is found.

Attwood's formula

A formula for determining the moment of static stability at large angles of heel of a ship. Taking angle of heel θ, and the weight of the ship W, the moment

where v is the volume of emerged wedge, hh₁ is the distance between the cg's of emerged and immersed wedges, V is the volume of displacement, B is the center of transverse buoyancy, and G is the center of gravity.

ATV

Acronym for "All Terrain Vehicle."

At your back door

Trucker slang for "behind your truck" as in "You got a Smokey at your back door!."

Auburn

A vehicle brand of which all 8 and 12-cylinder models from 1925-1948 are classic cars.

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Audax

A style of group bicycle touring found in Europe (esp. France) where a road captain sets a steady pace for a group of riders. All riders are to finish together, but (unlike regular randonneuring) a sag wagon is permitted.

Audax Club Parisien

A cycle-touring club in Paris, France which begun in 1904 to promote the audax style of randonneuring.


Audi A German automobile manufacturer which began in 1899 has four interlocking rings as its emblem. These rings represent the 1932 union of four automakers (Audi, DKW, Horch, and Wanderer). Later NSU joined in 1969. Audi was owned by Daimler-Benz from 1958 to 1965, and then by Volkswagen.	. Click for books on Audi

Audibility

Ability to be heard; said of faint sounds in the presence of noise. The extreme range of audibility is 20-20,000 Hz in frequency, depending on the applied intensity; and from 2 x 10^-5Nm^-2( ms) at 1000 Hz (the zero of the phon scale, selected as the average for good ears) to 120 d_B.

Audible ringing tone

An audible tone fed back to a caller as an indication that ringing current has been remotely extended to the called subscriber's telephone. On circuits in UK it is heard as a double beat recurring at 2 second intervals. Also called audible signal

Audible signal

See	audible ringing tone

Audio codec

A codec for use in a multimedia system, designed to handle a range of sound signals in addition to speech

Au diode

See	backward diode

Audio dub

Replacing the existing audio with new

Audio-frequency

Frequency which, in an acoustic wave, makes it audible. In general, any wave motion including frequencies in the range of 20 Hz to 20 k_Hz.

Audio-frequency amplifier

Amplifier for frequencies within the audible range.

Audio-frequency choke

Inductor with appreciable reactance at audio-frequencies.

Audio-frequency modulation

Method of facsimile transmission in which tone values from black to white are represented by a graded system of audio-frequencies

Audio-frequency transformer

Transformer for use in a communication channel or amplifier, designed with a specified, normally uniform, response for frequencies used in sound reproduction.

Audiogram

Standard graph or chart which indicates the hearing loss (in bels) of an individual ear in terms of frequency.

Also see
objective noise meter sound-level meter

Audiometer

Instrument for measurement of acuity of hearing. Specifically to measure the minimum intensities of sounds perceivable by an ear for specified frequencies.

Also see
noise audiometer

Auditory perspective

See	stereophony

Auger effect

For an atom which has been ionized by the ejection of an inner electron, the loss of energy by the ejection of an outer electron. Energies of the Auger electrons emitted are characteristic of the atomic energy levels, provided a method of determining surface composition and character.

Auger yield

For a given excited state of an atom of a given element, the probability of de- excitation by Auger process instead of by X-ray emission.

Augmentor

[1] Means of increasing forces by afterburning in a gas turbine.

[2] Means of increasing forces by induced airflow in a rocket.

[3] Means of increasing forces in a wing of STOL aircraft by ducting compressed air flow from a gas turbine into circulation-increasing slots and flaps to create high lift coefficients, thereby giving slow landing speeds.

Aural masking

See	masking

Aureole

Liminous glow from the outer portion of electric arc which has a spectrum different from that of the highly-ionized core.

Auroral zone

Zone where radio transmission is affected by aurora

Ausforming

Working an alloy steel in the metastable austenite condition. The material is first heated to a temperature where the austenite is stable, i.e., above the Ac₃ temperature, and is then cooled rapidly to the region of 550°C and worked to shape before any transformation to pearlite or bainite takes place. It transforms to martensite on cooling at ambient temperature and is then tempered. Strength and toughness are enhanced compared with the same material worked conventionally in the austenite region and quenched and tempered as separate operations.

Also see
isothermal transformation diagram

Austempering

Heating a steel to transform it to austenite followed by cooling rapidly to a temperature above the martensitic change point, but below the critical range, so that the austenite isothermally transforms to bainite, which has properties resembling a quenched and tempered steel of the same composition.

Also see
isothermal transformation diagram

Austenite

The higher density, high-temperature, face-centered cubic, γ form of iron and of solid solutions based on it. In pure iron it is stable between 1183K and 1663K.

Austenite bay

The shape of the region around 550°C in an isothermal transformation diagram which defines the zone where austenite is metastable and remains in that condition pending transformation to pearlite or bainite

Austenitic steel

Steel containing sufficient amounts of nickel, nickel and chromium, or manganese to retain austenite at atmospheric temperature, e.g., austenitic stainless steel and Hadfield's manganese steel

Austin Healey

A vehicle brand of which the 100-6 models from 1956-59 are milestone cars. The 3000 models from 1959-67 are milestone cars. The 100/100M model from 1953-56 are milestone cars.

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Austro-Daimler

A vehicle brand of which the 1925-1948 models are classic cars.

Authentication center

A node within a personal communications network containing the database files needed to check that potential users have authority to use the system.

Authority

See	Lean Authority Limit Switch

Authority Limit

See	lean Authority Limit Switch

Authority Limit Switch

See	lean Authority Limit Switch

Authorized dealer

A company which sells and services a particular brand of vehicle and is appointed or recommended by a manufacturer.

Auto

[1] Abbreviation for automatic transmission.

[2] Abbreviation for automobile.

Auto-adhesion

Bonding together of identical surfaces, as with contact adhesives.

Auto-assemble

System of videotape editing in which selected scenes are transferred in their required sequence according to a pre-selected program of time-code information.

Auto bonnet

A British term for a car cover.

Autocapacitance coupling

Coupling of two circuits by a capacitor included in series with a common branch

Autochoke

A term for automatic choke.

Autoclave

A sealable high-pressure container used for polymerization and in tire production.

Auto coarse pitch

The setting of the blades of a propeller to the minimum drag position if there is a loss of engine power during take-off

Autocollimator

[1] An instrument for accurately measuring small changes in the inclination of reflecting surfaces. Principally used for engineering metrology measurements.

[2] A convex mirror used to produce a parallel beam of light from a reflecting telescope. It is placed at the focus of the main mirror.

Autocorrelation

Technique for detecting weak signals against a strong background level. Signal is subjected to controlled delay, the original delay signals then being fed to the autocorrelation unit which responds strongly only if delay is an exact multiple of signal period.

Autocross

A timed competition of low-to-medium speed driving, with one driver at a time navigating a small course defined by traffic cones. Drivers compete against one another for the fastest timed lap (sometimes multiple laps) through the course.

Autocue

A visual prompter which displays a script to persons in front of a TV camera. Normally mounted on the camera to give eye contact with the viewers.

Autocycle

An obsolete moped which is a form of a light motorcycle with a small engine (usually below 100cc) that uses pedals to start the engine and provide some extra help getting up hills.

Auto dealer

A retail outlet that carries one (or in some cases in the U.S., a number of) manufacturer's product line and sells to general consumers and fleet operators. The outlet will also provide service and sell parts for the brand of vehicle that it carries. In some instances, a dealer may dual for another manufacturer's product line.

Autodealership

Autodyne

Term describing an electrical circuit in which the same elements and valves are used both as oscillator and detector. Also called endodyne, or self-heterodyne.

Autodyne receiver

A receiver utilizing the principle of beat reception and including an autodyne oscillator.

Autoflare

An automatic landing system which operates on the flare-out part of the landing, using an accurate radio-altimeter.

Autofocus assist

Device which improves autofocus performance in low light by projecting a high contrast light pattern onto the subject.

Also see
automatic focusing

Auto graveyard

An auto wrecker where a large number of older or disabled cars and trucks are located.

Autoignition

[1] The rapid burning of the air-fuel mixture as a result of a flame or hot surface, not from a spark plug.

[2] The self-ignition or spontaneous combustion of a fuel when introduced into the heated air charge in the cylinder of a compression-ignition engine. Also called automatic ignition.

Also see
spontaneous ignition temperature

Auto-inductive coupling

Coupling of two circuits by an inductance included in series with a common branch.

Autojumble

A British term for a "swap meet" where parts for old cars are displayed for sale in various stalls.

Autoland

A landing in which the descent, forward speed, flare-out, alignment with the runway, and touchdown are all automatically controlled.

Also see
autoflare autothrottle

Automated guided vehicle system

( AGVS) Vehicles equipped with automatic guidance equipment which follow a prescribed path, stopping at each machining or assembly station for manual loading and unloading of parts.

Automatic

[1] Colloquial term for automatic transmission.

[2] Anything that operates without the direct control of the driver.

Also see
automatic choke automatic gearbox automatic level control automatic temperature control automatic transmission automatic transmission fluid

Automatic adjuster

Brake adjusters that are actuated by the application of the park brake or by normal brake operation to compensate for lining wear. At one time, in order to activate the brake adjuster, it was necessary to operate the vehicle in reverse and hit the brakes.

Automatic adjusters

Brake adjusters that are actuated by the application of the parking brake or by normal brake operation, to compensate for lining wear.

Automatic advance

A mechanism which adjusts the ignition advance by means of centrifugal weights or by a diaphragm controlled by intake manifold vacuum.

Automatic air-conditioning

An air-conditioning system which automatically maintains a preset temperature.

Also see
automatic temperature control

Automatic air-recirculation system

A heating and ventilation system which automatically switches to the recirculation mode when the pollutant levels of the air inside the vehicle exceed certain levels; but after a certain period of recirculation, opens the intake air doors again to let some fresh air in, even if its quality is still questionable.

Automatic arc lamp

An arc lamp in which the feeding of the carbons into the arc and the striking of the arc are done automatically, by electromagnetic or other means.

Automatic arc welding

Arc welding carried out in a machine which automatically moves the arc along the joint to be welded, feeds the electrode into the arc, and controls the length of the arc.

Automatic beam control

( ABC) System in a TV camera which momentarily alters the beam current in the camera tube to reduce the tailing effects on moving highlights. Also called automatic beam optimizer

Automatic beam optimizer

See	automatic beam control

Automatic brightness control

Circuit used in some television receivers to keep average brightness levels of screen constant

Automatic call distribution

An intelligent network service which takes account of factors such as time of day or caller location to route calls to the appropriate point within an organization.

Automatic camera

Camera in which the focus lens aperture and shutter speed are selected automatically, film advance by motor drive may also be included. Priority selection may be available, for example, exposure based on either general or spot areas and with aperture or shutter speed limitations.

Automatic car wash

See	car wash

Automatic choke

A device attached to the carburetor that automatically reduces the amount of air entering the carburetor by sensing changes in engine temperature. It is usually controlled by a coil spring which changes length as the engine is warmed or cooled.

Automatic circuit-breaker

A circuit breaker which automatically opens the circuit as soon as certain predetermined conditions (e.g., an overload) occur.

Automatic closing system

A system which automatically closes the doors, windows, sunroof, trunk, and hood.

Automatic contrast control

Form of automatic gain control used in video signal channel of a television receiver.

Automatic control

[1] Valve action reached through self-operated or self-actuated means, not requiring manual adjustment.

[2] Switching system which operates control switches in correct sequence and at correct intervals automatically.

[3] Control system incorporating servomechanism or similar device, so that feedback signal from output of system is used to adjust the controls and maintain optimum operating conditions.

Automatic cut-out

A term frequently applied to a small automatic circuit breaker suitable for dealing with currents of a few amperes.

Automatic defrost

System of removing ice and frost from evaporators automatically.

Automatic direction finding

(ADF) Airborne navigational aid tuned to radio source of known position. Using rotatable loop aerial mounted above in aircraft to detect the direction of the radio source by rotating until the signal is zero.

Automatic expansion valve

( AEV) pressure-controlled valve which reduces high-pressure liquid refrigerant to low-pressure liquid refrigerant.

Also see
expansion valve

Automatic exposure

(AE) A control system using a photosensor in the camera to measure scene brightness and automatically set the lens aperture/shutter speed combination. Refinements include measuring particular areas of the scene and program exposure modes. A video camera uses the video signal to determine exposure.

Automatic flight control system

(AFCS) A category of automatic pilot for the control of an aircraft while en route. It can be monitored by speed and altitude data signals, signals from an instrument landing system and VOR, has automatic approach capability, and is disengaged before landing. Compare autoflare, autoland, autothrottle

Automatic focusing

(AF) Control system for automatically setting the lens focus to the subject distance; in a simple form, this may be by means of coupled range-finder but advanced types employ completely automatic examination of the image. In an enlarger or rostrum camera, lens focus is mechanically set by the distance from the base.

Automatic four-wheel drive

( A4WD) A driving system that automatically engages 4WD as needed, usually by monitoring differences in individual wheel speeds and thus sensing when a tire is slipping.

Automatic frequency control

(AFC) FM stations tend to drift a little, so radios have incorporated the frequency control to maintain the desired frequency automatically.

Automatic frost control

Control which automatically cycles refrigerating system to remove frost formation on evaporator.

Automatic gain control

(AGC) System in amplifiers which compensates for a wide range of input signals to give a more uniform level of output and thus accommodate for a wide range of conditions including fading, masking of antenna, and ambient light.

Automatic gearbox

See	automatic transmission

Automatic generating plant

A small generating station, e.g., a gasoline or diesel driven generator and battery which is automatically started when the battery voltage falls below a certain value and stopped when it is fully charged. The term is also applied to the plant in small unattended hydroelectric generating stations.

Automatic ice cube maker

Refrigerating mechanism designed to automatically produce ice cubes in quantity.

Automatic ignition

Rapid, out of control combustion of the air-fuel mixture in a spark ignition engine, but not caused by an external ignition source such as a spark, flame; instead, its caused by a hot spot such as a carbon deposit in the roof of the combustion chamber. Also called auto-ignition.

Automatic level control

A component of the suspension which raises or lowers either (or both) the front or rear of the vehicle when there is a change in the amount of load in the vehicle.

Automatic mixture control

A device for adjusting the fuel delivery to a reciprocating engine in proportion to air density.

Automatic muting

An automobile radio which cancels noise output when you turn the station dial.

Automatic observer

An apparatus for recording, photographically or electronically, the indications of a large number of measuring instruments on experimental research aircraft.

Automatic parachute

A parachute for personnel which is extracted from its pack by a static line attached to the aircraft.

Automatic phase control

In reproducing color TV images, the circuit which interprets the phase of the chrominance signal as a signal to be sent to a matrix.

Automatic pilot

A device for guiding and controlling an aircraft on a given path. It may be set by the pilot or externally by radio control. Also called autopilot. Colloquially called George

Automatic quiet gain control

Joint use of automatic gain control and muting

Automatic reel change

On rotary machines, equipment to attach a new reel to an old web, without stopping the machine and severing the butt end of the old web. Also called autopaster or flying paster.

Automatic ride control

Electronically operated soft or firm ride as required.

Automatic screw machine

Fully automatic single-spindle or multiple-spindle bar stock turret lathe.

Automatic seat belt

See	inertia reel seat belt

Automatic shutter

In a film projector, a shutter which cuts off the light when the mechanism stops, to protect the film from heat.

Automatic signalling

A system of railway signalling, usually with electric control, in which the signals behind a train are automatically put to "danger" as soon as the train has passed, and held in that position until the train has attained the next section of line.

Automatic slip-control differential

( ASD) An electronically controlled, automatic locking differential developed by Mercedes-Benz.

Automatic speed control

See	cruise control

Automatic stabilizer

A form of automatic pilot, operating about one or more axes, adjusted to counteract dynamic instability. Also called autostabilizer.

Also see
damper

Automatic starter

A starter for an electric motor which automatically performs the various starting operations (e.g., cutting out steps of starting resistance) in the correct sequence, after being given an initial impulse by means of a push-button or other similar device.

Automatic steering effect

Built in tendency of an automobile to resume travel in a straight line when released from a turn.

Automatic stoker

See	mechanical stoker

Automatic substation

A substation containing rotating machinery which, as occasion demands, is started and stopped automatically, e.g., by a voltage relay which operates when the voltage falls below or rises above a certain predetermined value.

Automatic synchronizer

A device which performs the process of synchronization in an ac circuit automatically

Automatic tap-changing equipment

A voltage-regulating device which automatically changes the tapping on the winding of a transformer to regulate the voltage in a desired manner.

Automatic temperature control

A system which regulates the heater and air conditioner so that the temperature inside the vehicle meets the preset temperature.

Automatic test equipment

( ATE) An electronic equipment for testing ignition, wiring, fuel injection systems, etc.

Automatic tracking

[1] Servo control of radar system operated by a received signal, to keep antenna aligned on target.

[2] Maintenance of head-track alignment in a helical scan VTR over a range of playback speeds. This may be achieved by control signals recorded in the video tracks (instead of a control track) or by sensing variations in radio-frequency amplitude caused by azimuth recording, with either being used to adjust the servo mechanism or the position of heads on piezoelectric mounts.

Also see
dynamic track following

Automatic train stop

A catch, used in conjunction with an automatic signalling system, which engages a trip-cock on the train passes a signal at danger.

Automatic transmission

A mechanism of the drivetrain which takes the power from the engine and transfers it to the driveshaft or wheels. Without using a clutch, it uses a torque converter and fluid coupler to change the gear ratio. It automatically effects gear changes to meet varying road and load conditions. Gear changing is done through a series of oil operated clutches and bands.

Automatic transmission fluid

( ATF) A very thin viscosity liquid designed for use in automatic transmissions to transfer the movement of the torque converter to the driveshaft. However it is also recommended for use in the forks of motorcycles. When poured into the throat of an automobile carburetor, it helps to remove a build-up of carbon on the cylinder head and the domes of pistons.

Automatic trolley reverser

An arrangement of the overhead contact line of a tramway, located at terminal points, which ensures that the trolley collector is reversed when the direction of motion of the car is reversed.

Automatic tuning

[1] System of tuning in which any of a number of predetermined transmissions may be selected by means of push-buttons or similar devices.

[2] Fine tuning of receiver circuits by electronic means, following rough tuning by hand.

Automatic voltage regulator

A voltage regulator which automatically holds the voltage of a distribution circuit or an alternator constant within certain limits, or causes it to vary in a predetermined manner.

Also see
automatic tap-changing equipment moving-coil regulator

Automatic volume compression

Reduction of signal voltage range from sounds which vary widely in volume, e.g., orchestral music. This is necessary before they can be recorded or broadc##ast but ideally requires corresponding expansion in the reproducing system to compensate.

Automatic volume control

( AVC)[1] Alteration of the contrast (dynamics) of sound during reproduction by any means. By compression (compounder) a higher level of average signal is obtained for modulation of a carrier, the expansion (expander) performing the reverse function at the receiver. In high-fidelity reproduction, arbitrary expansion can be disturbing because of variation in background noise, if present.

[2] An automobile radio which automatically limits the maximum volume to a preset level.

Automatic volume expansion

Expansion of dynamic range, e.g., by keeping peak level constant and automatically reducing the lower levels. Used to counteract loss of dynamic range through studio or recording equipment, or during transmission.

Automatic wear adjuster

A device that automatically compensates for the wear of brakes or clutch.

Automatic welding

Welding in which the work, the torch, and/or the arc is mechanically moved and controls are used to control the speed and/or the direction of travel.

Automatic white balance

(AWB) A self-adjusting balancing system which monitors the lighting and corrects for changes in color temperature

Automatic wire stripper

A tool which removes the outer insulation from a wire by automatically adjusting to the size of the wire thus avoiding damaging the wires.

Automixte system

A system of operation of gasoline-electric vehicles in which a battery, connected in parallel with the generator, supplies current during starting and heavy-load periods and is charged by the generator during light-load periods. Also called Pieper system

Automobile

Four-wheeled passenger motor vehicle having a seating capacity for not more than 10 people. It includes police cars and racing cars but not ambulances, hearses, or trucks. In Britain, the word "automobile" is not in frequent use and has been replaced by "motor car."

Automobile association

A motoring club which provides assistance to drivers including insurance, maps, travel arrangements, etc.

Also see
AA AAA Royal Automobile Club

Automobile Club

See
AA AAA Royal Automobile Club

Automobile engineering

See	automotive engineering

Automobile industry

The manufacturing industry for building automobiles. Also called motor industry.

Automobile insurance

A plan which a motorist can purchase for his vehicle which will offset the repair costs of a vehicle which has been involved in an accident. Some plans are offered by a government agency while others are run by independent agencies. All plans offer the basic coverage of property damage and public liability. Others offer extra benefits which cover glass damage, theft, vandalism, etc.

Automobile Labelling Act

See	American Automobile Labelling Act

Automobile manufacturer

An company which designs, builds, and distributes cars and trucks. Also called motor manufacturer.

Automobile mechanic

An individual who repairs and maintains cars and trucks. Also called (especially in Britain) motor mechanic.

Automobile polish

A wax or synthetic which is designed to give a glossy, protective finish to a painted surface. Also called car polish..

Automotive

Relating to or occurring in automobiles.

Automotive adhesive

A glue used in the manufacturing of automobiles.

Automotive electrician

An individual who works with designing the electrical system for automobiles.

Automotive electronics

The use of electronic equipment in automobiles.

Automotive emissions

All the different types of fumes that are expelled into the atmosphere (exhaust gas, fuel fumes, crankcase fumes) as well as the noise it makes.

Automotive engineering

The design and construction of automobiles.

Automotive Engineers

See	society of Automotive Engineers

Automotive gas oil

(AGO) US term for gas oil used mainly as diesel fuel; same as the UK term DERV

Automotive Repair and Service Council

See	Canadian Automotive Repair and Service Council

Automotive tool

Any of the tools used in the construction, maintenance, or repair of automobiles.

Autonomics

Study of self-regulating systems for process control, optimizing performance.

Autonomous vehicle

Generally unmanned aircraft operating without external assistance

Auto Pact base year

With respect to the Auto Pact, the 12 month period beginning on August 1, 1963, and ending on July 31, 1964.

Auto Pact Canadian value added

The aggregate of the costs of parts, material, labour costs, and transportation costs that are reasonably attributed to the production of vehicles or parts by manufacturers producing vehicles in Canada.

Autopar

Trade name of Chrysler Corp for its automobile parts (i.e., AUTOmobile_PARts). Chrysler also uses the name Mopar to indicate its motor parts (i.e., MOtor_PARts).

Auto parts store

Jobber and retail auto parts stores which primarily sell automotive products and conduct business at the retail level.

Autopaster

See	automatic reel change

Autopilot

See	automatic pilot

Autoplate

A machine which can deliver a curved stereoplate for rotary printing; built to suit the requirements of each particular rotary machine.

Autoradiograph

Photographic record, usually of a biological specimen, produced by exposure to radiation from self-contained radioactive material which has been injected or absorbed.

Auto-reclose circuit breaker

A circuit breaker which, after tripping due to a fault, automatically recloses after a time interval which may be adjusted to have any value between a fraction of a second and 1 or 2 minutes

Auto reverse

A feature on a cassette player which will automatically play the next side of a cassette tape when one side is finished.

Autorotation

[1] The spin; continuous rotation of a symmetrical body in a uniform air-stream due entirely to aerodynamic moments.

[2] Unpowered rotorcraft flight, in a helicopter with engine stopped, in which the symmetrical airfoil rotates at high incidence parallel with the airflow.

Autoset level

A form of dumpy level for rapid operation, in which the essential features are a quick-levelling head, and an optical device which neutralizes errors of levelling so that the bubbles need not be central while an observation is being made.

Autostabilizer

See	automatic stabilizer

Autostick

A trademark name for a form of semi-automatic transmission. It combines an automatic transmission with the gear-shifting feature of a manual transmission without the use of a foot-operated clutch. In the normal automatic transmission drive mode, the transmission behaves like any other automatic. The manual-shifting feature allows more control over the full range of rpms an engine offers. Porsche and Audi offer a related transmission technology called "Tiptronic." The Lexus GS400 also has a similar transmission but instead of using a stick to change gears it employs buttons on the steering wheel. Several other automakers offer similar technologies.

Autosynchronous motor

See	synchronous induction motor

Autothermic piston

An aluminum piston in which steel or alloy inserts are cast to control expansion of the piston skirt.

Autothrottle

A device for controlling the power of an aero-engine to keep the approach path angle and speed constant during an automatic blind landing.

Autotransductor

Transductor in which the same winding is used for power transfer and control

Autotransformer

Transformer in which both primary and secondary coils have turns in common. Step-up or step-down of voltage is accomplished by taps on common winding.

Autotransformer starter

A starter for squirrel-cage induction motors, in which the voltage, applied to the motor at starting is reduced by means of an autotransformer.

Auto wrecker

A place where old and disabled cars and truck go. The parts are removed and sold. Also called an auto graveyard.

AUX

Abbreviation for "auxiliary" usually indicating those terminals on the fuse panel for non-standard equipment.

Auxiliary

Additionally, supplementary.

Auxiliary acceleration pump

( AAP) a pump that increases driveability during cold engine operation by providing an extra amount of fuel to the acceleration nozzle to supplement the main acceleration pump.

Auxiliary air bleeds

Used on some idle systems to add air to the idle system downstream from the regular idle air bleed; they act in parallel with idle air bleed.

Auxiliary air intake

[1] An air intake for accessories, cooling, cockpit air, etc.

[2] Additional intake for turbojet engines when running at full power on the ground, usually spring loaded so that it will open only at a predetermined suction value.

Auxiliary air valve

A device which allows air to bypass a closed throttle during engine start and warm-up, in order to maintain a higher idle speed. The auxiliary air valve provides extra air into the intake manifold during cold engine starting for a higher idle speed during warm-up.

Auxiliary brake light

Additional brake lights mounted at eye level in the rear window or on the rear fenders. They are designed to give a following vehicle more notice of your presence and intention of stopping.

Auxiliary contact

See	auxiliary switch

Auxiliary drive shaft

A secondary drive shaft which powers the fuel pump, water pump, or distributor.

Auxiliary driving lamp

A light which supplements the headlights such as a fog light or spot light.

Auxiliary driving light

A light which supplements the headlamps such as a fog light or spot light.

Auxiliary gearbox

An extra gearbox used in conjunction with the main (manual) gearbox to provide an additional range of speeds.

Auxiliary gauge

The gauge which indicates compressor inlet pressure on older Chrysler Corporation vehicles with an Evaporator Pressure Regulator ( EPR) valve; also used to measure evaporator pressure on some Ford vehicles with a Suction Throttling Valve ( STV).

Auxiliary leaf

An extra leaf in a set of leaf springs. Also called helper leaf or helper spring.

Auxiliary lighting

Extra lighting such as fog lights, spot light, and driving lights which are intended to improve visibility under adverse conditions.

Auxiliary plant

A term used in generating-station practice to cover the condenser pumps, mechanical stokers, feed-water pumps, and other equipment used with the main boiler, turbine, and generator plant.

Auxiliary pole

See	compole

Auxiliary power unit

(APU) An independent airborne engine to provide power for ancillary equipment, electrical services, starting, etc. May be a small reciprocating or turbine.

Auxiliary rotor

A small rotor mounted at the tail of a helicopter, usually in a perpendicular plane, which counteracts the torque of the main rotor; used to give directional and rotary control to the aircraft.

Auxiliary shaft

In an overhead cam engine, a separate shaft that drives devices such as the fuel pump, the oil pump, and the distributor.

Auxiliary switch

A small switch operated mechanically from a main switch or circuit breaker; used for operating such auxiliary devices as alarm bells, indicators, etc. Also called auxiliary contact

Auxiliary tanks

See	fuel tank

Auxiliary transmission

Additional gear box increasing the gear ratio combinations when used with main transmission or multi-speed axles.

Auxiliary venturi

See	booster venturi

Auxiliary winding

A special winding on a machine or transformer, additional to the main winding.

Auxometer

An apparatus for measuring the magnifying power of an optical system

Available power efficiency

The ratio of electrical power available at the terminals of an electroacoustic transducer to the acoustical power output of the transducer. The latter should conform with the reciprocity principle so that the efficiency in sound reception is equal to that in transmission.

Available power gain

The ratio of the available power output of an amplifier to the input power; equal to power gain only when the output of the device or circuit is correctly matched to the load.

Avalon

A model of automobile manufactured by Toyota

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Click for books on Toyota Avalon

Avant

See	traction avant

AVC

Acronym for "automatic volume control."

Average

[1] A calculation in which the mean value or rate is determined. The average speed is determined by dividing the distance by the time (e.g., 273 kilometers divided by 3 hours = 91 kph). Average fuel consumption is determined as a ratio of fuel and distance. In the metric system, this is determined by multiplying the number of liters by 100 and dividing the result by the number of kilometers (e.g., 31.38 liters times 100 divided by 273 kilometers = 11.49 liters / 100 km). In the Imperial system divide the number of miles by the amount of fuel in gallons (e.g., 173 miles divided by 6.9 gallons = 25 mpg).

[2] Loss or damage of marine property, less than total compensation payment in proportion to amount insured.

Average current

The current obtained by adding together the products of currents flowing in a circuit and the times for which they flow and dividing by the total time considered. For direct current the average value is constant; for true alternating current, the average value is zero.

Average Fuel Economy

See	Corporate Average Fuel Economy

Average haul distance

The distance between the center of gravity of a cutting and that of the embankment formed from material excavated from the cutting.

Average power output

In an amplitude-modulated transmission, the radio-frequency power delivered by a transmitter, averaged over one cycle or other specified interval of the modulating signal.

Average weekly earnings

Gross taxable payrolls divided by the number of employees.

Avgas

Abbreviation for aviation gasoline.

Also see
aviation spirit

Aviation bi-phase shift keying

A digital modulation scheme in which a "1" is represented by a +90° phase transition and a "0" by a -90° transition of the carrier

Aviation fuel

A high octane fuel used primarily in aircraft but also used in racing vehicles to improve performance. Generally liquid hydrocarbons, because of high heat of combustion per unit of fuel mass (specific energy) and volume (energy density), ease of combustion, moderate volatility and viscosity, and good thermal stability and capacity. Liquid hydrogen and pentaborane (B₅H₉) have also been used experimentally.

Also see
aviation gasoline aviation kerosine

Aviation gasoline

(AVGAS) Blends of liquid hydrocarbons, almost all petroleum products boiling between 32° and 220°C, with anti-knock rating from 80 octane number to 145 performance number. Only small quantities are now used.

Also see
aviation fuel aviation kerosine

Aviation kerosine

For gas turbine engines, fuel which typically boils over the range 144°- 252°C. Variants include Jet A-1 (AVTUR), the international jet fuel; Jet B (AVTAG), a blend of naphtha with kerosine now being phased out except for use in cold climates; AVCAT, a naval jet fuel with high flash-point for safety in enclosed spaces in ships; AVPIN, an aviation isopropyl nitrate; and AVGARD, trade name for an additive with anti-misting properties.

Also see
aviation gasoline

Aviation spirit

(avgas) A motor fuel with a low initial boiling point and complying with a certain specification, for use in aircraft. Ranges from 73 to 120/130 octane rating.

Also see
aviation kerosine wide-cut fuel

Aviatrix

Female aviator

Avionics

The collective word for a spacecraft or aircraft's subsystem elements which involve electronic principles. A contraction of "aviation electronics."

A-vis

See	vis-a-vis

Avoidance system

See	collision avoidance system

Avpin

Abbreviation for aviation isopropyl nitrate

Avpol

Abbreviation for aviation petrol, oil, and lubricant

Avtag

Abbreviation for aviation wide-cut turbine fuel.

Also see
wide-cut fuel

Avtur

Abbreviation for aviation turbine fuel.

Also see
aviation kerosine

AWACS

Abbreviation for airborne warning and control system

Aware

See	environmentally aware

AWB

Acronym for automatic white balance

AWD

Acronym for "all-wheel drive."

Awl

A pointed or flat tool used to probe nail holes and injuries as well as for installing a repair plug.

Awning

A canvas roof which is stretched out from a parked trailer or camper to give protection from the sun and rain.

Awning deck

A superstructure deck, as the name implies. In its simplest form, it is the top deck of a two-deck ship, and places the ship in a certain category for scantling and freeboard.

Axe

Trade name for a range of digital switches manufactured by the Swedish company I. M. Ericsson Telefonaktiebolaget.

Axes

Plural of axis

Axial compressor

[1] A compressor characterized by the unusual piston arrangement. The pistons are arranged horizontally around and parallel to the crankshaft axis or centerline.

[2] A multistage, high-efficiency compressor comprising alternate rows of moving and fixed blades attached to a rotor and its casing respectively.

Axial engine

Turbine engine with an axial-flow compressor.

Axial-flow compressor

A compressor in which alternate rows of radially-mounted rotating and fixed airfoil blades pass the air through an annular passage of decreasing area in an axial direction.

Axial-flow turbine

Characteristic aero-engine turbine, usually of 1-3 rotating stages, in which the gas flow is substantially axial

Axial pitch

The distance from any point on one thread or helix to the corresponding point on the next thread or helix measured along the axis of the screw or helix.

Axial ratio

Ratio of major to minor axis of polarization ellipse for e.g., a wave propagated in waveguide, polarized light. Also called ellipticity

Axial response

The response of a microphone or loudspeaker, measured with the sound- measuring device on the axis of the appearance being tested.

Axial runout

Variation from the plane normal to its axis of a rotating part. Its wobble, rather than its eccentricity. Compare radial runout

Axiotron

Valve in which the electron stream to the anode is controlled by the magnetic field of the heating current

Axis

[1] The centerline, whether real or imaginary, around which a thing rotates.

[2] One of the three axes of an aircraft, which are the straight lines through the center of gravity about which change of attitude occurs longitudinal or drag axis in the plane of symmetry (roll); normal or lift axis vertically in the plane of symmetry (yaw); and the lateral or pitch axis transversely (pitch).

Also see
wind axes

[3] Of a lens, the line of symmetry of the optical system; the line along which there is no refraction.

Also see
cam-ground piston eccentric bolt hotchkiss drive kingpin axis kingpin inclination	moment of inertia pivot axis roll axis self-aligning torque static balance	steering-swivel axis steering axis inclination steering axis steering geometry steering knuckle angle.	swivel axis torque trailing arm

Axis inclination

See	steering axis inclination swivel axis inclination

Axis of a weld

An imaginary line along the center of gravity of the weld metal and perpendicular to a cross section of the weld metal.

Axle

An axle is a shaft on which the wheels revolve. A full-floating axle is used to drive the rear wheels. It does not hold them on nor support them. A semi-floating or one-quarter floating axle is used to drive the wheels, hold them on, and support them. A three-quarter floating axle is used to drive the rear wheels as well as hold them on, but it does not support them. A live axle holds the wheels and transmits power to the wheels. A dead axle or beam axle merely holds the wheels, but does not transmit power to the wheels.

Also see
ackermann axle back axle banjo axle beam axle cambered axle dead axle de Dion axle driven axle driving axle drop-center axle dropped axle dual axles	Elliot axle Elliot type axle front axle full-floating axle gross axle weight rating hypoid axle I-beam axle Jeantaud axle and steering live axle low pivot swing axle rear axle crossmember rear axle differential	rear axle housing rear axle ratio reverse-Elliot type axle reversed Elliot axle rigid axle rigid axle connection semi-floating axle slewed axles spread axle steering axle stub axle swing axle .	tandem axle three-quarter floating axle torque tube axle trailing axle twin axle twist-beam rear axle two-speed axle weissach axle z-axle.

Axle and steering

See	jeantaud axle and steering

Axle articulation

The degree to which an axle can move up and down. Off-road vehicles need a great deal of axle articulation to allow for extremely uneven terrain, such as rocks or gullies.

Axle-box

Box-shaped housing containing the axle bearings and lubricant. Constrained laterally on guides and supports the weight of vehicle through springs.

Axle casing

A British term indicating a tubular housing which encloses the differential and half-shafts along with their bearings. The US term is "axle housing."

Axle connection

See	rigid axle connection

Axle crossmember

See	rear axle crossmember

Axle differential

See	rear axle differential

Axle drive

The ring gear and pinion inside a differential housing.

Also see
final drive

Axle end gear

See	axle end gears

Axle end gears

The two gears, one per axle, that are splined to the inner ends of the drive axles. They mesh with and are driven by the spider gears.

Axle flange

Flange to which a road wheel attaches at the end of an axleshaft.

Axle housing

An American term indicating a tubular housing which encloses the differential and half-shafts along with their bearings. The British term is "axle casing."

Also see
rear axle housing, banjo type rear axle housing rear axle housing, split type

Axle housing banjo

See	rear axle housing, banjo type

Axle housing banjo type

See	rear axle housing, banjo type

Axle housing split

See	rear axle housing, split type

Axle housing split type

See	rear axle housing, split type

Axle load

See	axle weight

Axle parallelism

Axles are determined to be parallel, thus minimizing tire wear, if a measurement between two or more axles is equal at both ends of the axle.

Axle ratio

See	back axle ratio rear axle ratio

Axles

See	dual axles

Axle shaft

[1] The short shaft which connects the differential and the drive shaft on each side of an independent suspension configuration.

[2] The drive shaft or halfshaft of a rigid axle.

Axle stand

An adjustable height tripod used to support a vehicle when working underneath it. Although you can raise the car with the jack, use an axle stand for safety.

Axle track

Distance between centerlines of tire tread measured across axle.

Axle tramp

A form of wheel hop which is usually found in live rear axle cars. It occurs when sudden torque loads on the suspension cause the driven wheels to shake violently by slightly rotating the wheels and then springing back.

Axle tube

The part of the axle housing which covers the half-shaft or a tubular rigid axle.

Axle weight

The part of the weight of the vehicle which rests on the wheels of the axle.

Also see
gross axle weight rating

Axle weight rating

See	gross axle weight rating

Axle wind up

The phenomenon in which the torque transmitted to the wheels by the axle which causes the live axle to turn in its own centerline.

Axonometry

Measurement of the axes of crystals

Ayrton

See	Senna, Ayrton

Azeotrope

Having constant maximum and minimum boiling points.

Azeotropic mixture

Example of azeotropic mixture refrigerant R-502 is mixture consisting of 48.8 % refrigerant R-22 and 51.2% R-115. The refrigerants do not combine chemically, yet azeotropic mixture provides refrigeration characteristics desired

Azimuth

[1] The angle between the vertical plane containing a line or celestial body and the plane of the meridian, conventionally measured from north through east in astronomical computations, and from south through west in triangulation and precise traverse work.

Also see
azimuth angle

[2] The angle, normally 90°, between the direction of motion of the film or tape and the slit or gap in the optical or magnetic head.

Also see
bearing

Azimuthal power instability

Abnormal neutron behavior which results in uneven nuclear conditions in the reactor

Azimuth angle

Horizontal angle of observed line with reference to true north.

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