Dictionary of Automotive Terms Abbreviations

DICTIONARY OF AUTOMOTIVE TERMS - "Co"

CO: Acronym for Carbon monoxide. A deadly, colorless, odorless, and tasteless gas found in the engine Exhaust. Toxic even in relatively small concentrations. Formed by incomplete burning of Hydrocarbons. Thus at its greatest with a rich mixture.

CO₂: Acronym for Carbon dioxide

CO₂ indicator: Instrument used to indicate the percentage of carbon dioxide in stack gases.

Coach

An enclosed two-door type body with permanent back Panels and top, it is similar to the Coupe, but the seating is different. A full width cross seat in the rear accommodates three passengers. Two separate seats in the front fold out of the way to admit rear passengers. There is no Trunk, but trunk racks are frequently provided.
A luxurious bus, a tour bus.

Coach bolt: A bolt with a mushroom head, but just below the head there is a square neck and then the threads. The square neck fits into a matching square hole to keep the bolt from moving.

Coachbuilder: A person or company which manufactures special bodies for automobiles.

Coachbuilt body: A separate body which is not integral with the chassis.

Coachbuilt construction: The process of building an automobile so that the body is separate from the chassis. Often the bodies are built to customer specifications and may differ from one another even though they are built upon the same chassis design.
Also See
Skeleton construction
Unitary construction

Coachlining: Pinstriping along the side of a vehicle or along the side of the fuel tank of a motorcycle.

Coach paint: A slow-drying, high-gloss paint used on cars in the early 1900s. It was painted on car bodies with a brush.

Coachwork: Although it is strictly the body of an automobile, it is particularly the comfort and luxury appointments as distinguished from the operational Chassis thus it would include the interior, seats, Upholstery, dashes, fenders, etc. -- everything but the mechanicals and the chassis. The French call it Carrosserie, the Germans call it Karosserie, and the Italians call it Carrozzeria. Also called "bodywork."

Coal Bed Methane: Prior to the mid-1980's, methane from coal seams was classified as an uneconomic resource--one of vast potential, but low value due to poor recovery rates and high associated water production. By applying new production technologies to this resource, coalbed methane has become the single largest new source of gas supply in the past decade. Current estimates show approximately 100 Tcf of coalbed methane that appears to be economically recoverable in the lower 48 states alone. Methane is generated during coal formation and is contained in the coal microstructure. Typical recovery entails pumping water out of the coal to allow the gas to escape. Methane is the principal component of natural gas. Coal bed methane can be added to natural gas pipelines without any special treatment.

Coal bucket: Colloquial term for a dump trailer, coal trailer, or coal truck

Coalescing action: The process of smaller water droplets merging together into larger droplets which takes place in a water separator

Coal gas: A fuel gas substitute for natural gas obtained synthetically through the carbonization (distillation by heat in the absence of air) of coal. Typical coal gas mixtures include high concentrations of hydrogen and carbon monoxide.

Coal gasification: The process of converting coal into gas. The basic process involves crushing coal to a powder, which is then heated in the presence of steam and oxygen to produce a gas. The gas is then refined to reduce sulfur and other impurities. The gas can be used as a fuel or processed further and concentrated into chemical or liquid fuel.

Coal liquefaction: A chemical process that converts coal into clean-burning liquid hydrocarbons, such as synthetic crude oil and methanol.

Coal Synfuel: Coal-based solid fuel that has been processed by a coal synfuel plant; and coal-based fuels such as briquettes, pellets, or extrusions, which are formed from fresh or recycled coal and binding materials.

Coal Trailer: usually refers to a dump trailer, or a coal hopper bottom. Also called coal bucket

Coal Truck: usually refers to a dump truck used to haul coal. Also called coal bucket

Coaming: See
Hatch coaming

Coarse: See
National coarse thread

Coarse-cut file: A file with deep grooves for removing a lot of metal quickly. It leaves rough edges which will need to be cleaned up with a smooth-cut file

Coarse file: A file with deep grooves for removing a lot of metal quickly. It leaves rough edges which will need to be cleaned up with a smooth-cut file

Coarsening: See
Grain coarsening

Coarse pitch: Gears or screw threads which have wide gaps between each tooth or thread.
Also see
Auto Coarse Pitch

Coarse thread: The threads of a screw are wider apart. Opposite to fine thread.
Also See
National coarse thread
Unified National Coarse Thread

Coast

To proceed, usually downhill, on a Bicycle without pedaling; or in a motor vehicle without the aid of the engine.
Also See
Freewheel.
A designation on a cruise control switch which (when activated) will cause the vehicle to slow down to a lower cruise controlled speed.

Coastal: Domestic shipping routes along the coast.

Coaster: A vehicle, usually a Bicycle, which has no means of propulsion (you can't pedal it and it is without any engine).

Coaster brake: A braking system on a Bicycle in which the rider stops pedaling forward (thus coasting) and pedals backward to engage the brake within the Hub of the rear wheel.

Coat

A covering of paint or similar substance.
To apply a covering of paint, etc.
Single coat means to apply one layer of material on a surface. Double coat -- to apply two coats of adhesive, coating, or sealer to a surface. In spaying, it means to spray first a single coat with vertical strokes and then a second coat across with horizontal strokes, or vice versa

Also See
Anodize
Base coat
Clear coat
Color coat
Cross-hatch coat
Cross coat
Double Coat
Finish coat
Fog coat
Gel coat
Guide coat
Intermediate coat
Mist coat
Prime coat
Protective coat
Single coat
Tack coat
Top coat
Undercoat

Coat drier: See
Top coat drier

Coated abrasive: Sandpaper or grinding wheel where an abrasive material such as sand or diamond grit is glued to a backing material and used to reduce or smooth a surface.

Coated electrode: See
Covered electrode

Coated Membrane: See
Catalyst Coated Membrane

Coating: A protective covering usually of paint.
Also See
Anodic coating
Anti-chip coating
Catalyst Coating
Catalytic layer
Cathode Coating
Chromate coating
Conversion coating
Electrostatic powder coating
Galvanized coating
Hard anodic coating
Manganese phosphate coating
Phosphate coating
Polymer coating
Protective coating
PVC underseal coating
Roll coating
Spray coating
Underbody coating
Undercoating
Zinc phosphate coating

Coat oven: See
Top coat oven

Coaxial cable: Coaxial cable

An electric cable that has a solid inner conductor surrounded by a tubular outer conductor.

Cobble: To put something together in a rough or clumsy manner. This is usually done as a temporary measure until more permanent repairs can be made.

Cobbled: The action of putting something together in a rough or clumsy manner. This is usually done as a temporary measure until more permanent repairs can be made.

Cobra: See
AC Shelby Cobra

COC: Acronym for Conventional oxidation catalyst

Cock: A tap or shut-off valve which controls the flow of liquid.
Also See
Fuel cock
Radiator drain cock

Cockpit: The area, usually in racing cars, in which the driver sits and the instruments in front of him.

Code: A system of symbols (as letters, numbers, or words) used to represent meaning of information.
Also See
Nordic Anti-Corrosion Code
Barred Code
Baudot Code
Diagnostic Code
Diagnostic Trouble Codes
Edge Code
Hard Code
Highway Code
Ignition-latched Soft Code
National Electrical Code
Nordic Anti-corrosion Code
Self-diagnostic Code
Service Codes
Trouble Code

Codec: See
Audio Codec

Coded: See
Color-coded

Code hopping: A technology which prevents thieves with scanners from either picking up your encoded remote-control signal or from randomly firing numerous codes at your vehicle in order to stumble upon the one that will disarm your security system.

Code installation: Refrigeration or air conditioning installation which conforms to the local code and/or the national code for safe and efficient installations.

COE: Acronym for Cab-Over-Engine

Coefficient: See
Absorption coefficient
Attenuation Coefficient
Beam-coupling Coefficient
Block coefficient
Drag coefficient
Emission Coefficient
Negative Temperature Coefficient
Positive Temperature Coefficient
Temperature Coefficient

Coefficient of apparent expansion: The coefficient of expansion when the expansion of e.g., a dilatometer is neglected.

Coefficient of conductivity: Measure of the relative rate at which different materials conduct heat. Copper is a good conductor of heat and, therefore, has a high coefficient of conductivity.

Coefficient of drag: See
Drag coefficient

Coefficient of expansion

Increase in unit length, area, or volume for one degree rise in temperature.
The fractional change in length, area or volume per unit change in tem of a solid, liquid, or gas at a given constant pressure. e.g., an aluminum bar stretches 12 millionths percent of its original length for each degree F rise in temperature. Also referred to as "expansivity"

Coefficient of friction

A ratio of the force required to slide an object over a surface to the mass of the object, and is always less than 1.00
A measurement of the amount of Friction developed between two objects or surfaces in physical contact when one of the objects is drawn across the other. If a book were placed on a table and a measuring scale used to pull the book, the amount of weight or pull registered on the scale would be the coefficient of friction. This coefficient of friction is dependent upon both surfaces in contact. It is large if the surfaces are rough and small if they are smooth.

Coefficient of performance: (COP) Ratio of work performed or accomplished as compared to the energy used.

Coefficient Thermistor: See
Negative Temperature Coefficient Thermistor
Positive Temperature Coefficient Thermistor

COFC: Acronym for Container On Flat Car -- a method for moving shipping containers which involves transporting them on railroad flat cars.

Cofferdam: Narrow void space between two bulkheads or floors

Cofiring: The process of burning natural gas in conjunction with another fuel to reduce air pollutants.

Cog: Any toothed gear. A Sprocket attached directly to the rear wheel Hub on a single-speed bike and mounted on a Freewheel on a multi-speed bike.
Also see
Cassette Cogs

Cog belt: Cog Belt

A toothed belt normally of Fiberglass-reinforced rubber for driving the Camshaft from the Crankshaft. In cars, cog belts are primarily used with overhead camshafts but are sometimes used to drive Pumps.

Cogeneration: Primary source of energy that is also used to produce a secondary source of energy. Example The use of waste heat from an electrical energy generation system to heat a building.

Cogeneration appliance: A device that has a primary function of producing energy, but also can produce a secondary source. For example the primary function of a vehicle engine is to provide motive power, but the heat of the engine can also produce heat for the passengers.

Cogged belt: See
Cog belt

Cogging: Nonuniform angular velocity, i.e., rotation occurring in jerks or increments rather than smooth motion. When an armature coil enters the magnetic field produced by the field coils, it tends to speed up and slow down when leaving it. This effect becomes apparent at low speeds. The fewer the number of coils, the more noticeable it can be

Coil

Metal bands or strands of wire wrapped in a circular fashion.
Coil

A pulse-type transformer for increasing the Voltage to fire the Spark plugs.

Also See
Air Coil
Air-spaced Coil
Arc-suppression Coil
Basket Coil
Booster coil
Bucket Coil
Close coils
Exciter coil
Field coil
Four-spark ignition coil
Glow coil
Heating Coil
High energy coil
Hold-in coil
Holding coil
Ignition coil resistor
Ignition coil
Multi-spark coil
Multi-spark ignition coil
Pick-up coil
Recuperative Coil
Reheating Coils
Single-spark ignition coil
Temperature-Sensitive Bimetal Coil
Thermostatic coil choke

Coil binding: Compressing a valve spring to the point at which each coil touches the adjacent coil

Coil chimney: The top of the ignition coil where the high tension leads are attached.

Coil choke: See
Thermostatic coil choke

Coil ignition: The standard ignition system which uses an ignition coil which stores the power from the battery and steps it up. Then the high voltage is sent to the spark plugs.
Also See
Battery Coil Ignition
Transistorized coil ignition

Coil ignition with Hall sensor: See
Transistorized coil ignition with Hall sensor

Coil lead: A British term for the high tension wire going from the coil to the distributor. In America, it is called the coil wire.

Coil resistor: See
Ignition coil resistor

Coils: See
Close coils

Coil spring

Spring

A section of Spring steel rod wound in a spiral pattern or shape. Widely used in both Front and Rear suspension systems. Like large metal bed springs, these coils cushion and absorb the shocks and bumps as the vehicle is driven. They are usually found near the front wheels, but some cars have them in the rear as well. Often the Shock absorbers run up the center of the coil springs.
A coiled metal spring used in a suspension fork. Generally considered to be plusher, but heavier, than air springs.

Coil spring clutch: Click image to supersize
Coil Spring Clutch

An assembly that connects the engine to a manual transmission and consists of an engine flywheel, clutch disc, and pressure plate. The pressure plate is bolted to the flywheel and turns with it. The clutch disc is a flat steel disc with a splined hub that slides on the transmission input shaft. A ring of strong springs squeeze the clutch disc between the flywheel and pressure plate. When the clutch disc is locked in place, engine power passes from flywheel to clutch disc to transmission input shaft, thereby driving the car.

Coil spring compressor: See
Spring compressor

Coil tester: See
Spark gap coil tester

Coil tower: The top of the ignition coil where the high tension leads are attached.

Coil wire: The high tension wire going from the coil to the distributor or spark plug.

Coin holder: A device which retains coins for easy access.

Coke

As a product of coal. A solid carbonaceous residue derived from low-ash, low-sulfur bituminous coal from which the volatile constituents are driven off by baking in an oven at temperatures as high as 1100°C so that the fixed carbon and residual ash are fused together. Coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace. Coke from coal is grey, hard, and porous and has a heating value of 24.8 million Btu per ton.
As a product of petroleum. A residue high in carbon content and low in hydrogen that is the final product of thermal decomposition in the condensation process in cracking. This product is reported as marketable coke or catalyst coke. The conversion is 5 barrels (of 42 U.S. gallons each) per short ton. Coke from petroleum has a heating value of 6.024 million Btu per barrel.

Coke breeze: The term refers to the fine sizes of coke, usually less than one-half inch, that are recovered from coke plants. It is commonly used for sintering iron ore.

Coke button: A button-shaped piece of coke resulting from standard laboratory tests that indicates the coking or free-swelling characteristics of a coal; expressed in numbers and compared with a standard.

Coked up: A British term for carboned up to indicate something covered in carbon.

Coke oven gas: The mixture of permanent gases produced by the carbonization of coal in a coke oven at temperatures in excess of 1,000°C.

Coke plants: Plants where coal is carbonized for the manufacture of coke in slot or beehive ovens.

Coking: Thermal refining processes used to produce fuel gas, gasoline blendstocks, distillates, and petroleum coke from the heavier products of atomspheric and vacuum distillation. Includes: Delayed Coking, Flexicoking, and Fluid Coking

Cold

The relative absence of heat
A temperature considerably below normal.

Cold air: Air that is below the prevailing ambient temperature.

Cold air induction: The induction system forces cold air into the Combustion chamber. Because cold air is more dense than warm air, it contains more oxygen molecules. With more oxygen, fuel will burn more effectively and thus increase horsepower.

Cold air intake: The induction system forces cold air into the Combustion chamber. Because cold air is more dense than warm air, it contains more oxygen molecules. With more oxygen, fuel will burn more effectively and thus increase horsepower.

Cold cap: A process in retreading a tire where the tire is placed in a pressure Chamber in a temperature range of 91°C to 100°C until bonding of the pre-cured tread rubber is achieved.

Also See
Hot cap

Cold Chisel: Cold Chisel

A thick pencil shaped tool with a sharp flat end like a blade screwdriver. When you hit the blunt end with a hammer, it forces the blade end into metal to mark it or even cut through it.

Also See
Splitting chisel

Cold-condensate corrosion: The corrosion of the inside of an exhaust system by direct chemical attack resulting from an acidic, aqueous solution that condenses from the exhaust gas at relatively low temperatures and collects at the cooler rear portions of the exhaust system.

Cold cranking ability: A measurement in amps of a battery's ability to start a vehicle under cold temperatures. A higher number is better than a lower one. Basic automobile batteries begin around 400 cold-cranking amps (which is only marginally acceptable in most vehicles). The best batteries are around 1000 cold-cranking amps.

Cold cranking amps: See
Cold cranking ability

Cold-cranking rating: The minimum number of amperes a fully charged 12-volt battery can deliver for 30 seconds at -18°C without falling below 7.2 battery volts

Cold engine compensator: When an engine is cold a richer mixture of fuel is required. The cold engine injector supplies more fuel to compensate for the condensation of fuel against the cold combustion chamber walls and intake manifold

Cold Filter Plugging Point: (CFPP) A measure of the ability of a diesel fuel to operate under cold weather conditions. Defined as the lowest temperature at which diesel fuel will pass through a fine wire mesh screen of the test apparatus.

Cold forming: A process of shaping an object (esp. made of stainless steel without heating it or using only a little heat below recrystallization temperature. The object is pressed into shape by appropriate dies at high speed in order to give the object increased tensile strength and hardness as well as a decrease in ductility. Also called cold heading or cold working

Cold galvanizing: The application of zinc to prevent rusting. It can be applied by a paint with lots of zinc or by electroplating with zinc.

Cold heading

A process of shaping an object (esp. made of stainless steel without heating it or using only a little heat below recrystallization temperature. The object is pressed into shape by appropriate dies at high speed in order to give the object increased tensile strength and hardness as well as a decrease in ductility. Also called cold forming or cold working
Forcing metal to flow cold into dies to form thicker sections and more or less intricate shapes. The operation is performed in specialized machines where the metal, in the form of a wire or bar stock, may be upset or headed in certain sections to a larger size and, if desired, may be extruded in other sections to a smaller diameter than the stock wire.

Cold idle speed solenoid: Cold Idle Speed Solenoid

A motor or solenoid operated by the computer can also be used to push a plunger against the throttle linkage in order to increase cold-idle speed.

Cold in-place recycling: A system of re-using pavement that may have a lot of potholes, or is otherwise in poor shape. The top layer of old pavement (about 3 inches) is broken up with hand tools or by a paving machine. Asphalt binder is added to the ground up pavement, processed, and laid back down on the road. The paving machine will do this in one continuous operation. The new recycled mat will then be topped with a surface treatment or an asphalt overlay. This process is used on medium or low-volume roads.

Cold junction: That part of a thermoelectric system which absorbs heat as the system operates.

Cold lash: The valve lash clearance, measured between the rocker arm and valve tip, when the engine is cold.

Cold manifold: An intake manifold not heated by exhaust gas

Cold mixture Heater: (CMH) (CHM) A device which helps to reduce cold engine emissions and improve driveability during engine warm-up.

Cold plug: A spark plug which has a short insulator nose which absorbs less heat and dissipates heat quickly. A colder plug is used in a hot engine while a hot plug is used in a cold engine. Thus if the plugs are fouling too much, try a hotter plug. If the plugs are coming out white, try a colder plug. The ideal color of the center insulator nose should be a light chocolate brown.

Cold solder joint: A poor soldering technique where the solder has not quite melted enough to produce a good electrical contact.

Cold spark plug: See
Cold plug

Cold spraying: A method of paint spraying where the paint is excessively diluted with solvent. This process makes spraying easy, but the coats are very light.

Cold start: Getting a vehicle started which has been sitting for some time and cooled down to ambient temperature. When temperatures reach -40°C, a vehicle may require three or four times as much battery power as it would during the summer. As well, the carburetor or fuel injection system needs to be much richer (more gasoline than air). Because condensation has a tendency to build up in the gas tank during the winter, the liquid going to the carburetor or fuel injectors may be diluted with water -- thus making starting more difficult. The application of isopropyl alcohol (marketed as gasline antifreeze) removes the water from the tank.

Cold starting: See
Cold start

Cold start injector valve: A device which supplies fuel under cold temperature depending on coolant temperature and the starter signal. Voltage is suppled by the Fuel pump relay

Cold start enrichment: A method of providing a higher ratio of fuel to air for starting a cold engine. In some cases, more fuel is fed into the engine with a Cold start injector; in other cases, the amount of air is restricted through the use of a Choke.

Cold start injector: A device in a fuel injection system which shoots an extra amount of fuel into the cylinder to increase the ratio of fuel to air.

Cold start valve: See
Cold start injector

Cold Swaging Process: A method of working with steel or other material without application of heat to reduce or form it by drawing to a point or reducing the diameter, as required.

Cold wall: Refrigerator construction which has the inner lining of refrigerator serving as the cooling surface.

Cold weather modulator: (CWM) a vacuum modulator located in the air cleaner on some models. The modulator prevents the air cleaner duct door from opening to non-heated intake air when outside air is below 13°C. Similar to a temperature vacuum switch.

Cold Work: Metal stock that is deformed by hammering, forming, drawing, etc., while the metal is at room temperature and no heat is applied.

Cold working: A process of shaping an object (esp. made of stainless steel without heating it or using only a little heat below recrystallization temperature. The object is pressed into shape by appropriate dies at high speed in order to give the object increased tensile strength and hardness as well as a decrease in ductility. Also called cold forming or cold heading

Collagen: A gluey protein found in vertebrates. It forms the principal substance in connecting fibers and tissues and in bones, hydrolizing to gelatin when boiled with water to become the primary ingredient in glue

Collapse: See
Piston collapse

Collapsed piston: A Piston whose Skirt diameter has been reduced due to heat and the forces imposed upon it during service in the engine.
Also See
Piston collapse

Collapsible spare tire: A Space-saver spare.

Collapsible steering column: When a vehicle is involved in an accident, the driver's chest is forced into the steering wheel. In older cars, the immovable steering column meant that the driver could sustain chest damage. The collapsible steering column telescopes or folds (articulate) so that chest damage is reduced.

Collar: A sleeve that fits over a shaft.
Also See
Hexagonal collar
Underhead collar
Valve spring collar

Collector

A person who accumulates specialty vehicles
Semiconductor section of transistor, connected to the same polarity as the base.

See
Air collector
Current collector
Liquid Collector
Low Temperature Collectors
Medium-Temperature Collector
Solar collector
Solar Thermal Collector
Special Collector
Unglazed Solar Collector

Collector car: An older car which may not fit into the category of a Classic car or a Milestone car, but it has nostalgic appeal.

Collet: A removable ring or collar which fits into a groove to hold something in place.

Collier: Vessel used for transporting coal.

Collision: See
Head-on collision

Collision avoidance system: Electronic system used to prevent collisions in inland navigable waterways.

Collision bulkhead: The foremost main transverse watertight bulkhead designed to keep water out of the forward hold in case of bow collision damage. Also called Forepeak bulkhead

Collision insurance: Insurance coverage that pays to repair damages to your vehicle when it is involved in an accident.

Colloids: Miniature cells peculiar to meats, fish, and poultry which, If disrupted, cause food to become rancid. Low temperatures minimize this action.

Colonnade hardtop: Colonnade Hardtop

In architecture, the term colonnade describes a series of columns, set at regular intervals, usually supporting an entablature, roof, or series of arches. To meet US federal rollover standards in 1974 (standards that never emerged), General Motors introduced two-door and four-door pillared body types with arch-like quarter windows and sandwich type roof construction. They looked like a cross between true hardtops and miniature limousines. Both styles proved popular (especially the coupe with louvered coach windows and canopy top) and the term colonnade was applied. As their true hardtops disappeared, other manufacturers produced similar bodies with a variety of quarter-window shapes and sizes. These were known by such terms as hardtop coupe, pillared hardtop, or opera-window coupe.

Color: See
Four color
Identification color
Integral color anodizing
Off color
Paint color matching

Color anodizing: See
Integral color anodizing

Color chart: A listing of paint samples of available exterior paint for a vehicle.

Color coat: A coat of paint with the final color. Sometimes a clear coat is applied over it.

Color-coded

Something that is colored the same as the main part of the bodywork. Also called color-keyed or color-matched.
A series of similar things in which each one is a different color to distinguish one from the other, such as the wiring (e.g., the red wire goes from the battery to the fuse box, the blue wire goes from ... to the ...).

Colored: See
Body-colored

Colorimeter: See
Tag-Robinson Colorimeter

Color-keyed: See
Color-coded.

Color-matched: See
Color-coded.

Color matching: See
Paint color matching

Color scheme: The combination of exterior colors which harmonize, e.g., A maroon body and a white roof.

Columbium: A metal which may be added to chrome-nickel stainless steel to improve its welding and general heat-resistant qualities, by preventing carbide precipitation.

Columbus: Italian manufacturer of high quality bicycle frame tubes.

Column: See
Collapsible steering column
Energy absorbing steering column
Height adjustable steering column
Mercury Column
Steering column
Telescopic steering column
Tilt column Water Column

Column changer: See
Column shifter

Column controls: See
Steering column controls

Column gear changer: See
Column shifter

Column shifter: A gear changer lever and mechanism which is located on the steering column below the steering wheel. In Britain it is called a column changer or column gear changer.

Combi: Vessel designed for a combination of passengers, and different types of cargo.

Combination: A vehicle like a motorcycle and sidecar or a tractor and trailer.

Combination brake system: A dual brake system that uses disc brakes at the front wheels and drum brakes at the rear wheels

Combination lamp: A light or group of lights which serves two or more purposes. For example, the rear combination lamp illumines the running lights (i.e., the ones that are turned on when the headlight is turned on) and brake light and/or the signal light

Combination pliers: A British term for a Lineman's pliers or slip-joint pliers

Combination spanner: A British term for Combination wrench

Combination tooth lock washer: Combination tooth lock washer

A hardened circular washer with twisted prongs of teeth protruding from both the inside and the outer edge of the washer.

Combination valve

A brake system hydraulic control device includes a pressure differential valve, metering valve, and proportioning valve
A hydraulic valve usually incorporating a pressure differential warning switch, a metering valve and a proportioning valve. Not all combination valves contain all of these control valves
A single housing that combines two or more hydraulic valves used in a braking system

Combination Vehicle: A vehicle made up of two or more separate units hooked together, such as a tractor-semitrailer combination. Also called an articulated vehicle since units pivot at the coupling point.
See
Long Combination Vehicle
Longer Combination Vehicle

Combination weight: See
Gross combination weight

Combination wrench: Combination Wrench

A flat wrench with a hex ring at one end and an open end at the other.

Combined weight rating: See
Gross Combined Weight Rating

Combiner: See
Holographic combiner

Combo: See
Shifters brake Lever Combo

Combustible dust: See
Respirable Combustible Dust

Combustible liquids

A liquid having a flash point at or above 37.8°C. They are subdivided as follows:

Class II Liquids--Those having flash points at or above 37.8°C and below 60°C.
Class IIIA Liquids--Those having flash points at or above 60°C and below 93.4°C.
Class IIIB Liquids--Those having flash points at or above 93.4°C.

Combustible materials: Items adjacent to or in contact with heat-producing devices (e.g., engine, manifold, exhaust pipe, muffler, heater, warm air ducts, etc.) which are made of or surfaced with wood, compressed paper, plant fibers, or other materials that are capable of being ignited and burned. Such materials shall be considered combustible even though flameproofed, fire-retardant treated, or plastered.

Combustion

The rapid oxidation of fuel accompanied by the production of heat, or heat and light.
The intense burning of the Fuel-air mixture in the Combustion chamber. Some used to think that the Fuel-air mixture exploded; but further investigation has shown that it rapidly burns.

Also See
Combustion chamber volume
Combustion chamber
Compression ignition
Controlled combustion system
External combustion engine
Fireball combustion chamber
Gross Heat Of Combustion
Hemispherical combustion chamber
Internal combustion engine
Main combustion chamber
Net Heat Of Combustion
Pent-roof combustion chamber
Pre-combustion chamber
Swirl Combustion
Wedge combustion chamber

Combustion air: Air required for safe and proper combustion of fuel gas.

Combustion Chamber

Combustion Chamber

The Volume of the space in the Cylinder above the Piston with the piston at Top dead center (TDC) in the Compression stroke. The Head of the piston, the Cylinder walls, and the Head form the Chamber. Combustion of the Fuel-air mixture begins here when ignited by a Spark plug. The design and shape of the combustion chamber can affect power, Fuel efficiency, and emissions of an engine. Several combustion chamber shapes have been used including Hemispherical combustion chamber, Bathtub combustion chamber, Wedge combustion chamber, Squish combustion chamber, and Piston-crown combustion chamber.
An enclosed vessel in which chemical oxidation of fuel occurs.
The area at the top of the cylinder where the fuel charge burns and pushes the piston down

Also See
Annular Combustion Chamber
Cannular Combustion Chamber
Fireball combustion chamber
Hemispherical combustion chamber
Main combustion chamber
Pent-roof combustion chamber
Spherical combustion chamber
Twin swirl combustion chamber
Wedge combustion chamber

Combustion chamber recess: The area where combustion occurs in a rotary piston engine

Combustion chamber volume: Volume of combustion chamber (space above Piston with piston on TDC) measured in cc (cubic centimeters).

Combustion controls: A device which automatically regulates the firing rate at predetermined air-fuel ratios in accordance with load demand.
Also see
Modulating Combustion Controls

Combustion engine: See
External combustion engine
Internal combustion engine

Combustion pressure: The pressure created during the combustion of the air/fuel mixture in the cylinder, measured in pounds per square inch.

Combustion Process: See
Pulse Combustion Process

Combustion products: Constituents resulting from the combustion of a fuel with oxygen. For combustion processes that obtain oxygen from air, this includes the inert gases contained in air but excludes excess air used in the combustion.

Combustion residue: Carbon and other deposits resulting from combustion.

Combustion space: See
Combustion chamber.

Combustion system: See
Controlled combustion system

Comeback

A repair job which has been returned to the dealer because of a repeat problem. Usually the dealer is responsible to repair it properly at no charge to the customer.
Trucker slang for a return call or repeat as in "Can I get a come back on that smokey report?"

Comedian: Trucker slang for median strip as in "Smokey's in the comedian taking pictures."

Come on: A situation where a vehicle buyer is led to believe one thing but it turns out to be really something else.

CO meter: A device for checking exhaust gases for carbon monoxide, a high level indicates an over-rich mixture as well as causing pollution.

Comet head: A cylinder head with a swirl chamber for indirect injection diesel engines.

Comfort: A designation of some automobiles as a basic or standard line usually abbreviated as "C"

Comfort chart: Chart used in air conditioning to show the dry bulb temperature, humidity, and air movement for human comfort conditions.

Comfort cooler: System used to reduce the temperature in the living space in homes. These systems are not complete air conditioners as they do not provide complete control of heating, humidifying, dehumidification, and air circulation.

Comfort Luxe: An automobile designation (abbreviated as CL) which has more luxury appointments than a Comfort but less than a Grand Luxe (GL).

Comfort zone: Area on psychrometric chart which shows conditions of temperature, humidity, and sometimes air movement in which most people are comfortable.

Comic book: Trucker slang for Truck driver's log book as in "The chicken coops checking comic books this morning."

Coming on the cam: The term used when a four stroke reaches its powerband

Coming on the pipe: The term used when a two stroke reaches its powerband

Commerce Commission: See
Interstate Commerce Commission

Commercial Driver's License: (CDL) A US license which authorizes an individual to operate commercial motor vehicles and buses over 26,000 pounds gross vehicle weight. For operators of freight-hauling trucks, the maximum size which may be driven without a CDL is Class 6 (maximum 26,000 pounds gross vehicle weight). In Canada it is called a Class 1 license.

Commercial Motor Vehicle

A motor vehicle or combination of motor vehicles used in commerce to transport passengers or property if the motor vehicle meets one of the following

has a gross combination weight rating greater than or equal to 26,000 lb. including a towed unit with a gross vehicle weight rating of at least 10,000 lb.
has a gross vehicle weight rating of at least 26,001 lb.
is designed to transport 16 or more passengers including the driver
a motor vehicle of any size that transports hazardous materials of any kind.

Commercial tire: A tire which is designed for truck and industrial use.

Commercial vehicle: A vehicle (like a truck or bus) used for carrying goods or large numbers of passengers for money.

Commissioned agent: An agent who wholesales or retails a refined petroleum product under a commission arrangement. The agent does not take title to the product or establish the selling price, but receives a percentage of fixed fee for serving as an agent.

Commodity: Anything bought and sold.

Common Carrier: A freight transportation company which serves the general public. It may be a regular route service (over designated highways on a regular basis) or irregular route (between various points on an unscheduled basis).

Common Rail Injection: A diesel fuel injection system employing a common pressure accumulator, called the rail, which is mounted along the engine block. The rail is fed by a high pressure fuel pump. The injectors, which are fed from the common rail, are activated by solenoid valves. The solenoid valves and the fuel pump are electronically controlled. In the common rail injection system the injection pressure is independent from engine speed and load. Therefore, the injection parameters can be freely controlled. Usually a pilot injection is introduced, which allows for reductions in engine noise and NOx emissions.

Community car: Vehicle operated for community or voluntary purposes.

Community transport: Voluntary transport provision for groups with special access needs.

Commutator

A series or ring of copper bars that are connected to the Armature windings. The bars are insulated from each other and from the armature. The Brushes (as in the Generator or Starter) rub against the whirling commutator.
Part of rotor in electric motor which conveys electric current to rotor windings.

Also see
Cylindrical Commutator
Radial Commutator

Commutator motor: See
AC Commutator Motor

Compact: See
Compact car
Compact SUV
Sub-compact

Compact car: A designation no longer used because even full-size cars are now about the size of what was the compact car. In 1970, for instance, a Chevrolet Impala was a full-size car, a Chevelle was an intermediate, a Nova was a compact. When cars smaller than the Nova came out (i.e., Chevette), they were called sub-compacts.

Compacted snow: Snow that has been compressed by the movement of traffic and has bonded to the road surface

Compaction: Compressing roadway materials to their optimum density, providing a strong, stable surface.

Compactor: A device used to compact things, particularly garbage.

Compact SUV: Compact sport utility vehicle usually based on a car chassis rather than a truck chassis. They include such models as Ford Escape, Honda CR-V, Hyundai Tucson, Jeep Compass, Jeep Liberty, Jeep Patriot, Kia Sportage, Mazda Tribute, Mercury Mariner, Nissan Rogue, Saturn Vue, Suzuki Grand Vitara, Toyota RAV4.
Also see
Premium Compact SUV

Companionway: An access way in a deck, with a ladder leading below, for the use of the crew

Company automotive outlet: Any retail outlet selling motor fuel under the brand name of a company reporting in the EIA Financial Reporting System.

Company car: A vehicle owned by an organization rather than an individual. It may be operated by only one person or by several employees.

Company-lessee automotive outlet: One of three types of Company automotive outlets. This type of outlet is operated by an independent marketer who leases the station and land and has use of tanks, pumps, signs, etc. A lessee dealer typically has a supply agreement with a refiner or a distributor and purchases products at dealer tank wagon prices. The term includes outlets operated by commissioned agents and is limited to those dealers who are supplied directly by a refiner or any affiliate or subsidiary company of a refiner.

Company logo: An emblem which represents all or part of a company's trademark.

Company-open automotive outlet: One of three types of company automotive (retail) outlets. This type of outlet is operated by an independent marketer who owns or leases (from a third party that is not a refiner) the station or land of a retail outlet and has use of tanks, pumps, signs, etc. An open dealer typically has a supply agreement with a refiner or a distributor and purchases products based on either rack or dealer tank wagon prices.

Company-operated automotive outlet: One of three types of company automotive (retail) outlets. This type of outlet is operated by salaried or commissioned personnel paid by the reporting company.

Company-operated retail outlet

Any retail outlet (i.e., service station) which sells motor vehicle fuels and is under the direct control of a firm that sets the retail product price and directly collects all or part of the retail margin. The category includes retail outlets operated by

salaried employees of the firm and/or its subsidiaries and affiliates,
licensed or commissioned agents, and/or
personnel services contracted by the firm.

Comparison and identification: See
Program comparison and identification

Compartment: See
Battery compartment
Cassette compartment
Cluttered engine compartment
Crowded engine compartment
Engine compartment
Glove compartment
Passenger compartment

Compartmentation: The subdividing of the hull by transverse watertight bulkheads so that the ship may remain afloat under certain flooding conditions

Compass: An instrument with a magnetic needle which is mounted on the dash to give the driver an idea of where magnetic north might be.
Also see
Beam Compasses

Compass display: A digital readout of the direction in which the vehicle is pointed. Usually displayed on the dash, headliner, or the mirror

Compass mirror: Compass Mirror

An inside rear view mirror which incorporates a compass in one corner

Compatible: See
Look Compatible

Compensated Intracorporate Hauling: A freight transportation service provided by one company for a sister company.

Compensating bar: See
Compensator

Compensating jet: Click image to supersize
Compensating Jet

A fuel tube or pipe in the Carburetor, into which air is admitted through one or more holes to compensate for a tendency of the main Nozzle to deliver too rich a mixture as the air velocity through the Carburetor increases. Also called Air bleed.

Compensating port: A small hole in a Brake master cylinder to permit fluid to return to the reservoir.

Compensating Resistor: See
Load Compensating Resistor

Compensation: See
Altitude Compensation System
Attenuation Compensation
Backlight Compensation
Bass Compensation

Compensator: A horizontal bar which is pulled forward when the parkbrake is applied at its central point, which is pivoted, while it is connected at each end to the parkbrake cable, enabling equal force to be exerted on each rear brake.
Also See
Aneroid Altitude Compensator
Hot Idle Compensator
Temperature Compensator

Compensator valve: A valve in Automatic transmissions designed to increase the pressure on the Brake band during heavy Acceleration.

Competition: See
Interchannel competition

Competition car: A vehicle which is designed to compete in races, hill climbs, and rallies.

Complete respray: Painting the entire component or entire vehicle as opposed to a partial respray

Completion: In the oil or gas production, the installation of permanent equipment for the production of oil or gas. If a well is equipped to produce only oil or gas from one zone or reservoir, the definition of a Well (classified as an oil well or gas well) and the definition of a completion are identical. However, if a well is equipped to produce oil and/or gas separately from more than one reservoir, a well is not synonymous with a completion.

Completion date: In oil and gas production, the date on which the installation of permanent equipment has been completed as reported to the appropriate regulatory agency. The date of completion of a dry hole is the date of abandonment as reported to the appropriate agency. The date of completion of a service well is the date on which the well is equipped to perform the service for which it was intended.

Compliance: A slight resiliency, or give, designed into Suspension Bushings to help absorb bumps. Good compliance allows the wheels to move toward the rear a little as they hit bumps but does not allow them to move laterally (sideways) during cornering.

Compliance Certification Label: See
Safety Compliance Certification Label

Compole: An auxiliary pole used on a commutator machine. The pole is placed between the main poles for the purposes of producing an auxiliary flux to assist commutation.

Component

One of the parts that make up the whole system or device, as in The Brake pad is a component of the Brake system.
A raw material, ingredient, part or subassembly that goes into a higher level assembly, compound, or other item.

Also See
Body component
Cell Components
Motor Gasoline Blending Components
Primary structure component
Shared component

Component anti-lock brake system: A type of anti-lock brake system in which the hydraulic control unit is not a part of the master cylinder/power booster assembly.

Component assembly: A combination of two or more parts or sub-components to form an assembly.

Component design: The activity for the design of specific components including responsibility for material, cost, weight, reliability, durability, function, appearance, and serviceability.

Components: The various parts that make up the whole system or device.

Component sharing: The use of the same basic parts used in different models -- even in models from different manufacturers.

Composite: Any material that consists of two or more substances where one or more of them are high strength fibers and another is an adhesive Binder. The most common composite is Fiberglass, which consists of thin glass fibers bonded together in a plastic matrix. The structural properties of composites can be altered by controlling the orientation and configuration of the high-strength Components.

Composite brake drum: A brake drum made from two different metals. All composite drums have cast-iron friction surfaces.

Composite headlamps: Reflector and lens system designed for specific vehicle model

Composite headlight: A non-sealed beam Headlight used in the US since 1984, but available in other countries much earlier. Unlike the Sealed beam headlight, the lens and bulb are separate units. When the Bulb fails, you can replace just the bulb, not the whole unit. Lenses come in a variety of shapes and are designed for a specific vehicle. Even the left side differs from the right on the same vehicle. While sealed-beam headlights are mass produced for almost all early vehicles, composite headlight lenses are low production and can be very costly to replace.

Composite material: Structural material made of two or more different materials

Composite MPG: See
EPA Composite MPG

Composite propeller shaft: A single-piece propeller shaft made of fiber-reinforced epoxy in which the fibers are usually glass and/or carbon.

Composition: See
Antifouling Composition
Boiler Compositions

Compound

Two or more ingredients mixed together.
An Abrasive paste or liquid that smooths and Polishes the painted surface.

Also See
Anti-drum compound
Antiseize Compound
Cutting compound
Dielectric Silicone Compound
Gauge Compound
Intermetallic compound
Nonmethane Volatile Organic Compounds
Ozone compound
Rubbing compound
Sheet molding compound
Valve grinding compound
Volatile Organic Compounds

Compound carburetor: A carburetor with more than one choke. Usually there are two one for the large throttle opening and one for the small throttle opening, but they fit to a single port

Compound center electrode: Also called Compound electrode

Compound electrode: A spark plug with a copper core and a jacket of a nickel-based alloy.

Compound gauge

A gauge that can indicate both pressure and vacuum.
Another name for the Low side gauge, because it can indicate both pressure and vacuum

Compound glass: See
Laminated glass

Compounding: See
Pre-compounding

Compound motor: A direct current electric motor with two separate field windings, one in parallel and the other in series with the armature circuit; used as a starter motor

Compound refrigerating systems: System which has several compressors or compressor cylinders in series. The system is used to pump low-pressure vapors to condensing pressures.

Compound winding: Two electric windings -- one in series, the other in shunt or parallel with other electric units or equipment. Applied to electric motors or generators -- one winding is shunted across the armature; other is in series with the armature.

Comprehensive insurance: Insurance coverage that pays for damages to your car, its accessories, spare parts against loss or damage caused by an accidental collision, fire, theft, vandalism, typhoon, earthquake, and flooding. It will also pay expenses to have the disabled vehicle towed to the repair shop and expenses to return the vehicle back to you when the repairs are completed. It also covers for the death and bodily injury of the insured or driver; loss or damage to someone else's property as a result of the accident; legal liabilities to the death or bodily injury of the third party arising from the accident; legal liabilities to the damage to property of the third party arising from the accident; loss or damage to the property of the spouse(s) or the child(ren) of the insured or driver; and medical expenses of the insured or driver's injury caused by the accident.

Compress: To place under pressure or to squeeze into a small space.
Also See
Pre-compress

Compressed-air spray gun: A paint gun which makes a fine spray of paint for coating the surface.

Compressed natural gas: (CNG) Natural gas comprised primarily of methane that has been compressed under high pressures, typically between 2000 and 3600 psi, and held in a container. The gas expands when released for use as a fuel for natural gas powered vehicles.
Also See
Natural gas

Compression

Applying pressure to a spring, or any springy substance, thus causing it to reduce its length in the direction of the compressing force.
Applying pressure to a gas, thus causing a reduction in volume but an increase in pressure and temperature.
One of the essential factors in an internal combustion engine (fuel, air, proper proportion of mixture, compression, Timing, and Spark). It is the squeezing of the Fuel-air mixture in the cylinder of a spark-ignition engine or the squeezing of the air in a diesel engine. Compression makes the process of Combustion more effective and increases engine efficiency.
Term used to denote increase of pressure on a fluid by using mechanical energy.
Reduction in volume and increase in pressure and temperature of a gas caused by squeezing it into a smaller space
A system of forces that reduces the volume occupied by a specific quantity of gaseous material.
Natural gas is compressed during transportation and storage. The standard pressure that gas volumes are measured at is 14.7 psi. When being transported through pipelines, and when being stored, gas is compressed to save space. Pipelines have compressing stations installed along the line (one about every 100 miles) to ensure that the gas pressure is held high while the gas is being transported. Current pipelines can compress natural gas to nearly 1500 psi, but most tend to operate at closer to 1000 psi.

Also See
Adiabatic Compression
Automatic Volume Compression
Crankcase compression
Grooved compression ring
Heat Of Compression
High compression head
Primary compression
Primary compression ratio
Secondary compression

Compression check: Testing the Compression in all the Cylinders at Cranking Speed. All plugs are removed, the Compression gauge placed in one plug hole, the Throttle Cracked wide open and the engine cranked until the gauge no longer climbs. The compression check is a good way in which to determine the condition of the valves, rings, and Cylinders.

Compression damping: The control of the movement as the shock compresses as it hits a bump. Rebound damping refers to controlling the movement as the shock extends back to its relaxed position.

Compression gage: See
Compression gauge

Compression gauge

A gauge used to test the Compression in the Cylinders. A poor Compression reading can indicate that there is leakage through the valves or the Piston rings. In Two stroke engines, it could indicate that there is poor Primary compression because of a leak in the Crankshaft seals.
Instrument used to measure positive pressures (pressures above atmospheric pressures) only. Gauge dial usually runs from 0 to 300 lb. per sq. in. gauge, (psig) (101.3-2 170 kPa).

Compression head: See
High compression head

Compression height: The distance from the wrist-pin-bore center to the top of the piston.

Compression ignition

(CI)

Combustion of a Fuel-air mixture without Spark. In the Diesel engine, air is drawn into the Cylinder and compressed to a temperature sufficiently high that fuel oil injected at the end of the Compression stroke burns in the Cylinder without a spark to initiate Combustion. A prank played on new employees is to send them on a search for the Spark plugs for a diesel engine -- they don't exist.
The form of ignition that initiates combustion in a diesel engine. The rapid compression of air within the cylinders generates the heat required to ignite the fuel as it is injected.

Compression leakage: In an engine, when some gases escape past the piston because the rings or cylinder walls are worn, the compression is reduced so that there is less efficiency.

Compression molding: The shaping of molding material by softening it under pressure and the action of heat, and forcing it through a hole into a hollow space which it completely fills.
Also See
Molding

Compression moulding: British term for Compression molding

Compression ratio

When the Piston is at the bottom of its travel (BDC), the Volume of Cylinder is measured (suppose the volume is X). Then the piston is placed at the top of its travel (TDC) and the volume of the Cylinder is measured (suppose this volume is Y). The compression ratio is a comparison of these two values expressed as XY. Then the values are mathematically changed so that the second number is always 1. Thus you hear of ratios like 10.51 or 9.51 or 81. The higher the compression ratio, the more mechanical energy an engine can squeeze from its Air-fuel mixture. Higher compression ratios, however, also make Detonation more likely.
Ratio of the volume of the clearance space to the total volume of the cylinder. In refrigeration it is also used as the ratio of the absolute low-side pressure to the absolute high-side pressure.
Also See
Primary compression ratio

Compression ring: A ring which surrounds the Piston and fits in a grove in the piston. It is designed to seal the burning fuel charge above the piston. Generally there are two compression rings per piston and they are located in the two top Ring grooves. They also help to transfer heat from the piston into the Cylinder walls and subsequently to the Water jacket surrounding the Cylinder.
Also See
Grooved compression ring
Tapered compression ring

Compression spring: Coil Compression Spring

An open-coil, Helical spring that offers Resistance to a compressive form.

Compression stroke: Compression Stroke

The second stroke of the Four-stroke cycle, in which the Piston moves upward from Bottom dead center to Top dead center, compressing the Fuel-air mixture.

Compression tester: A device which is screwed or pushed into the spark plug hole so that when the engine is turned over, it measures the amount of compression in that cylinder.

Compressor

A device used for increasing the pressure and density of gas.
Pump of a refrigerating mechanism which draws a low pressure on cooling side of refrigerant cycle and squeezes or compresses the gas into the high-pressure or condensing side of the cycle.
A tool for compressing a coil spring, such as a valve spring.
An air conditioning component which pumps, circulates, and increases the pressure of refrigerant vapor
A mechanism in a refrigerator or Air conditioner that Pumps Vaporized Refrigerant out of the Evaporator, compresses it to a relatively high pressure and then delivers it to the Condenser.
Compressor

A device which produces pressurized air for filling tires and running air-powered tools

Also See
Air compressor
Axial Compressor
Axial-flow Compressor
Centrifugal Compressor
Clearance Pocket Compressor
Fuel gas compressor
Hermetic Compressor
Inline Compressor
Muffler Compressor
Multiple Stage Compressor
Open Compressor
Open Type Compressor
Piston compressor
Piston-type compressor
Positive displacement compressor
Radial Compressor
Reciprocating compressor
Roots compressor
Rotary Blade Compressor
Rotary Compressor
Semihermetic Compressor
Single-stage Compressor
Spring compressor
Stationary Blade Compressor
Valve spring compressor
Vanes Compressor
Variable Displacement Compressor
V-type Compressor

Compressor, centrifugal: Pump which compresses gaseous refrigerants by centrifugal force.

Compressor control: See
Motor control

Compressor cut-off switch: A device used by some manufacturers to prevent compressor operation. Such as the wide open throttle (WOT) cut-off switch, low pressure switch, and high pressure switch

Compressor discharge switch: A device that shuts off the compressor when refrigerant pressure is low. The switch is wired in series between the compressor clutch and the control panel switch

Compressor displacement: Volume, in cubic inches, represented by the area of the compressor piston head or heads multiplied by the length of the stroke.

Compressor, hermetic: Compressor in which the driving motor is sealed in the same dome or housing as the compressor.

Compressor impeller: An impeller of a turbocharger driven by the turbine at speeds up to 160,000 rpm, which accelerates by centrifugal force the charge air which enter axially and leaves radially at a very high velocity.

Compressor muffler: Sound absorber chamber in refrigeration system. Used to reduce sound of gas pulsations.

Compressor, multiple stage: Compressor having two or more compressive steps. Discharge from each step is the intake pressure of the next in series.

Compressor, open type: Compressor in which the crankshaft extends through the crankcase and is driven by an outside motor. Commonly called external drive compressor.

Compressor pressure ratio: In a turbocharger system, the ratio between the absolute pressure at the compressor outlet and the compressor inlet

Compressor ratio: In a turbocharger system, the ratio between the volume in the cylinder when the piston is at the bottom of its stroke and the volume in the cylinder when the piston is at the top of its stroke

Compressor, reciprocating: Compressor which uses a piston and cylinder mechanism to provide pumping action.

Compressor, rotary: Compressor which uses vanes, eccentric mechanisms, or other rotating devices to provide pumping action.

Compressor seal: Leakproof seal between crankshaft and compressor body in open type compressors.

Compressor shaft seal: A seal in an air conditioner compressor, surrounding the compressor shaft, that permits the shaft to turn without the loss of refrigerant or oil

Compressor Signal: See
Air Conditioner Clutch Compressor Signal

Compressor, single-stage: Compressor having only one compressive step between low-side pressure and high-side pressure.

Compressor station: Any combination of facilities that supply the energy to move gas in transmission or distribution lines or into storage by increasing the pressure.

Comprex supercharger: A supercharger using the pressure waves created by the expanding exhaust gases to compress the inlet charge. Also called pressure wave supercharger.

Companion flanges: Shaft attached collars of stainless steel into which a threaded piece may be joined.

Comparator: A device for inspecting screw threads and outlines by comparing them with a greatly enlarged standard chart.

Computer

A device which calculates information and sends the results to a specific destination. In automobiles, computers are used to regulate fuel flow, control the Air conditioner, display Speed, time, ETA, etc.
Series of electrical components which accept inputs from an operator and controls outputs.

Also See
Diagnostic computer
Fuel computer
On-board computer
Spark control computer
Trip computer

Computer-aided: Something which has been helped or designed by a computer.

Computer brake control: See
Anti-skid

Computer command control: (CCC) an electronically-controlled fuel metering system used on GM vehicle. Uses an oxygen sensor, a throttle position sensor and other information sensors to provide a computer with the data it needs to alter the air/fuel ratio via mixture control solenoid in the carburetor

Computer command control system: (C-3) an earlier engine management system used on GM vehicles. (C-4) A later engine management system used on GM vehicles

Computer-controlled: A function or component which is monitored or activated by a computer

Computer Controlled Catalytic Converter: (C-4) A later engine management system used on General Motors vehicles.

Computer controlled coil ignition: (C3I) GM's computerized ignition coil system, used on many different engine applications

Computer controlled timing: (CCT) a system that feeds input from various engine sensors into a computer. The computer then matches spark timing exactly to engine requirements throughout its full range of operations

Computerized Controller: See
Centralized Computer Controller

Computer languages: Specific wording or codes, such as BASIC, FORTRAN, and COBOL, which direct a computer to accept and store information and control outputs.

Computer Module: See
Body Computer Module

Con: See
Forked con rod
Master con rod

Concave drum: A deformed brake drum in which the diameter at the center of the friction surface is greater than that at the ends. Contrast Convex drum

Concave weld face: A weld having the center of its face below the weld edges

Concealed headlamps: Headlamp doors close to create a flush fitting surface to reduce air resistance in headlamp area

Concealed headlights: Concealed Headlights

Headlight which (when not lit) is hidden behind a panel. When the headlight switch is turned on, vacuum or an electric current is applied to a controller which opens the panel exposing the light. Also called hide-away headlights or pop-up headlights.

Concentration: See
Stress concentration

Concentrator: A reflective or refractive device that focuses incident insolation onto an area smaller than the reflective or refractive surface, resulting in increased insolation at the point of focus.

Concentric: Two or more circles so placed as to share a common center but different diameters.

Concept car: A vehicle that is not currently in production, but is still in the design stage. Some are merely paper drawings, but others are clay Mock-ups. The ideas in the concept cars sometimes appears in production models.
Also See
Prototype

Concept vehicle: A current production vehicle modified for installation of new design concepts for evaluation of environmental functional feasibility.

Concho: A chrome Trim disk for Saddlebags and leathers.

Concours: Also called concours d'elegance. This is the term used to describe a show where cars in superb condition are judged against a standard of excellence established by the sponsors, with awards given to winners. Show cars compete in a concours.

Concours d'elegance: See
Concours

Concrete: A mixture of cement, rocks, sand, and water which, when hardened, becomes a rock-like substance which can be used for barriers and even road surfaces.
Also see
Asphaltic concrete

Concrete Piles: See
Cast-in-situ Concrete Piles

Cond: Advertising abbreviation for condition, as in excellent cond.

Condensate

A fluid formed when a gas is cooled to its liquid state.
The liquid that separates from a gas (including flue gases) due to a reduction in temperature.

Also See
Cold-condensate corrosion
Plant Condensate

Condensate corrosion: See
Cold-condensate corrosion

Condensate pump: Device to remove water condensate that collects beneath an evaporator.

Condensation

Moisture, from the air, deposited on a cool surface. The reverse of Evaporation.
Liquid or droplets which form when a gas or vapor is cooled below its dew point.
The act or process of reducing a gas or vapor to a liquid or solid form

Also see:
Condensate
Heat Of Condensation
Latent Heat Of Condensation

Condense: Turning a vapor back into a liquid.

Condenser

The unit in an air conditioning system that cools the hot compressed Refrigerant and turns it from a vapor into a liquid. It is the opposite of an Evaporator.
Condenser

The part of ref