Dictionary of Automotive Terms Abbreviations

DICTIONARY OF AUTOMOTIVE TERMS - "Au"

Auburn: Click image for books on
Auburn

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

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

Audi: Click image for books on
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. It includes the 80 (1988-92), 90 (1988-95), 100 (1989-94), 200 (1989-1991), 5000 (1988), A3 (2006-2008), A4 (1996-2008), A6 (1995-08), A8 (1997-2007), allroad (2001-05), Cabriolet (1994-98), Q7 (2007), Quattro (1990-94), RS4 (2007), RS6 (2003), S4 (1992-2008), S6 (1995-2007), S8 (2001-2007), TT (2000-08)

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

Audi Rings: Audi Rings

A logo of four interlocking rings from the German automobile manufacturer Audi. These rings represent the 1932 union of four automakers (Audi, DKW, Horch, and Wanderer). Later NSU joined in 1969.

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 20k 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

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

Audit: See
Energy Audit

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

Means of increasing forces by afterburning in a gas turbine.
Means of increasing forces by induced airflow in a rocket.
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

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

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 1183°K and 1663°K.

Austin Healey: Click image for books on
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.

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

Abbreviation for Automatic transmission.
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

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

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

The rapid burning of the Air-fuel mixture as a result of a flame or hot surface, not from a Spark plug.
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.

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

Colloquial term for Automatic transmission.
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: Click to supersize
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

Valve action reached through self-operated or self-actuated means, not requiring manual adjustment.
Switching system which operates control switches in correct sequence and at correct intervals automatically.
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 Cruise Control: (ACC) A term found on a Cruise control witch which indicates the direction the switch needs to be moved to increase the speed (accelerate) of the vehicle

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, and 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 or flame; instead, it's caused by a hot spot such as a carbon deposit in the roof of the combustion chamber. Also called Auto-ignition.
Ignition of fuel at the burner when the fuel controlling device is turned on, including reignition if the flames on the burner have been extinguished by means other than by the closing of the fuel controlling device.

Automatic ignition system: A system designed to ignite and re-ignite a main burner.

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

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: 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

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

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 broadcast but ideally requires corresponding expansion in the reproducing system to compensate.

Automatic volume control

(AVC)

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

Also see
Quiet Automatic Volume Control

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: 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 classification: Vehicle classifications for automobiles and light duty trucks were obtained from the EPA mileage guide book. Almost every year there are small changes in the classifications, therefore the categories will change accordingly. The EPA mileage guide can be found at any new car dealership.

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.
Also see
Alliance Of Automobile Manufacturers

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 Research: See
United States Council For Automotive Research

Automotive Technical Education Foundation: See
National Automotive Technical Education Foundation

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

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

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 Control Valve: (AAC) 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 air intake

An air intake for accessories, cooling, cockpit air, etc.
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 regulator: A rotary gate valve which stabilizes idle speed during engine warmup

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 control valve: A unit which controls pressure in various portions of the brake system.

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 drum parking brake: Incorporates an an extra parking brake drum inside a rear rotor on some four-wheel drive disc brake systems.

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

Auxiliary power: Power from an independent source that functions as required to augment/support various performance criteria established for the prime power source.

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