A mark on the output (live) terminal on a generator (contrasts with F)
A bicycle maneuver in which the rider puts a foot down in order to catch his balance on a difficult section of trail as in, ‘You will be disqualified if you dab on this course.’
Abbreviation for Digital Audio Broadcast.
Abbreviation for Delayed Accessory Bus
A South Korean automobile manufacturer which produced Lanos (1999-2002), Nubira (1999-2002), Leganza (1999-2002).
Abbreviation for Delivered at Frontier and coupled with a named place. The seller fulfills his obligation to deliver when the goods have been made available, cleared for export, at the named point and place at the frontier but before the customs border of the adjoining country. The term ‘frontier’ may be used for any frontier including that of the country of export. Therefore it is of vital importance that the frontier in question be defined precisely by always naming the point and place in the term.
Virginia Ruth Egnor
1955 Cadillac ‘Dagmar’ bumper
Large bullet-shaped protrusion on bumpers of cars in the 1950s. It was named after the nickname of a buxom television star, Virginia Ruth Egnor (1921-2001).
Dagmar is an automobile of which only the 6-80 models are classic cars.
A brand of automobile from the Daihatsu Motor Co., Ltd. which began in 1951 and included the following models Rocky (1987-98), Charade (1977-2000)
To reduce the oscillations of spring, carburetor piston, etc.
To reduce the vibration in a crankshaft
A rubber belt wound around the outside of a brake drum or rotor prior to machining the drum or rotor. The belt dampens out vibrations that might affect the quality of the finished surface.
A friction device sometimes called a shock absorber. Used for controlling and damping spring oscillations. The springs actually absorb road shocks; the dampers convert the energy imparted to the springs into thermal energy (heat) (by friction), which is dissipated to the atmosphere or the vehicle’s chassis. Dampers are distinguishable by the type of friction involved, mechanical or hydraulic but most modern cars used tubular-shaped hydraulic shock absorbers. Because they affect up and down wheel motions, dampers are an important link in tuning a vehicle’s ride and handling.
Device which uses oil metered through orifices to control abrupt suspension movement.
A movable plate which permits or restricts the flow of liquids or gasses.
Springs in a clutch plate providing a cushion against sudden loads due to abrupt engagement
A suspension strut whose hub carrier is attached to the spring element rather than to the damper tube. Compare Macpherson strut
Cushioning of force.
The action of suspension to control the speed of movement through its travel, usually by a piston running through oil and thus gives a smoother ride. It vastly improves that smoothness of ride offered.
In very early cars, an upright wooden or metal panel at the front of the body. This was a holdover from days when the dashboard literally shielded the carriage from the horse manure and road splash that would dash up to the riders. In more modern cars, the word ‘dashboard’ is sometimes used interchangeably with the more correct term, instrument panel which contains the driving instruments, switches, etc. Sometimes called dash panel or just dash.
A term used in body engineering. In some car companies, the ‘dash line’ is an all-important measuring marker from which body-length dimensions are taken. During design, the actual ‘dash’ (firewall) is extensively altered to accommodate intrusion by the transmission, ducting, controls, etc., so it rarely coincides with the theoretical ‘dash’ and should never by confused with instrument panel
A structural panel with bracing across the width of the car on the inside of the bulkhead below the windshield that provides the mounting locations of the dashboard. Also called the fire wall because it is the partition between the passenger compartment and the engine compartment.
A truck or tractor without a sleeper birth. Typically used for day trips or local routes.
A system of sensors that assesses the amount of daylight and controls lighting or shading devices to maintain a specified lighting level. The sensors are sometimes referred to as photocells.
(DLO) The perimeter of any car window, including the windshield and backlight.
A mirror which adjusts to prevent the glare from the headlights of following cars. The British term is dipping mirror.
Number of days needed to sell all vehicles in inventory, based on the previous month’s sales rate.
Daytime running lights
(DRLs) A safety-oriented lighting system in which the headlights or other front lights are constantly on even during the day. They help to prevent possible accidents because oncoming traffic can be seen. December 1, 1989, Canada became the second country after Norway to require daytime running lights on all new passenger vehicles. In other countries the implementation of DRLs has had mixed response.
The glare from the headlights of oncoming traffic which can momentarily blind a driver.
A unit of measure for decibels, the measure of sound intensity or pressure named after Alexander Graham Bell. It is a logarithmic measurement; every 3dB increase represents a doubling of the sound pressure. The A in dBA indicates that the measurement was taken with an A-weighted scale; sound pressure varies across the audible spectrum, and the A-weighted scale approximates the human ear’s sensitivity to various frequencies.
DBA is an abbreviation for Doing Business As a common usage for a business license.
A special ‘instructions for motor vehicle drivers’ form issued by a government agency when transporting hazardous materials for the U.S. government. The pickup driver and the delivery driver must read and sign the form; the delivery driver gives it to the consignee when delivering the shipment.
Abbreviation for Distillers Dried Grains — An animal feed coproduct consisting of residual grain solids that have been dried to a moisture content of 10-12%.
Abbreviation for Distillers Dried Grains with Solubles — An animal feed coproduct very similar to DDG but also containing the process syrup as well as residual grain solids.
Abbreviation for Diagnostic Data Link
Abbreviation for Delivered Duty Paid plus the named place of destination. The seller fulfills his obligation to deliver when the goods have been made available at the named place in the country of importation. The seller has to bear the risks and costs, including duties, taxes, and other charges of delivering the goods thereto, cleared for importation. While the EXW term represents the minimum obligation for the seller, DDP represents the maximum obligation.
Abbreviation for Delivered Duty Unpaid plus the named place of destination. The seller fulfills his obligation to deliver when the goods have been made available at the named place in the country of importation. The seller has to bear the costs and risks involved in bringing the goods thereto (excluding duties, taxes, and other official charges payable upon importation as well as the costs and risks of carrying out customs formalities). The buyer has to pay any additional costs and to bear any risks caused by his failure to clear the goods for import in time.
Abbreviation for Drive End
An axle that does not rotate nor is driven but merely forms a base upon which to attach the wheels. Non-powered rear axle on tandem truck or tractor. Also called tag axle
The change in speed required before the governor will make a corrective movement of the throttle. This hesitation results from the lag in governor action caused by friction and lost motion in the governor mechanism. Also called sensitivity.
A battery that registers almost no electrical charge. Sometimes it can be brought back to life with a charger. The British call it a flat battery
The point at which the piston reaches its uppermost or lowermost position in the cylinder the rod CrankJournal would be at 11 o’clock UDC or 6 o’clock LDC.
A portion of a ship’s side or bottom where the plating has no curvature; also, the midship portion of constant cross section — the parallel middle body.
A section of road that is absolutely flat. A term often used for a road that is relatively flat since few roads are without at least some minor undulations.
Dead freight factor
The amount of a ship’s carrying capacity that is not used.
A cargo truck or trailer without any cargo that is being driven to a particular location
A trip where the tractor pulls an empty trailer or a trailer loaded with cargo that generates no revenue. Sometimes it can be company materials or goods
A ride-along driver
Operating a truck without cargo.
A fuel pressure reading taken directly at the fuel pump outlet. Many systems use a fuel pressure regulator; dead-head pressure is an unregulated measurement
A buried timber (etc.) that has an attached pipe or cable going to the surface for the purpose of securing a vessel at a dock or along a riverbank.
A footrest located to the far left of the driver so that he can brace his left leg during hard cornering or to balance the position of the right foot on the throttle pedal during normal driving.
Dead rear axle
A rear axle that does not turn. E.g., rear axle of front wheel drive car
The upward slant or rise of the bottom of a shiip from the keel to the bilge
The space below the piston available for pre-compression of the incoming fresh charge of the two-stroke engine.
Product that has been in inventory for an extended period of time without being moved or ordered.
The total weight in tons (2240 lb.) that a ship carries on a specified draft including fuel, water in tanks, cargo, stores, passengers, baggage, crew and their effects, but excluding the water in the boilers. It is the difference in weight between a vessel when it is fully loaded and when it is empty measured by the water it displaces.
(DWT) The lifting capacity of a ship expressed in long tons, including cargo, commodities, and crew.
A firm that buys and sells, adding some value for the consumer in the process. Dealer often means a firm which operates closer in the distribution channel to the consumer than a distributor or wholesaler and may add more value for consumers than either of the above-mentioned terms. Also called dealership.
A person whose business is buying and selling cars and trucks or motorcycles.
The amount contributed by the dealer to reduce the final purchase price in the lease contract. Dealer participation can take the form of a rebate or simply a discount. The dealer participation is reflected in the lease contract as a capitalized cost reduction.
The individual or corporation that owns and controls one or a number of auto dealerships.
A firm that buys and sells, adding some value for the consumer in the process. A dealership often means a firm which operates closer in the distribution channel to the consumer than a distributor or wholesaler and may add more value for consumers than either of the above-mentioned terms.
A local franchise individually owned, but supported by a vehicle manufacturer, that sells and services the manufacturer’s vehicles.
Dealer tank wagon sales
(DTW) Wholesale sales of gasoline priced on a delivered basis to a retail outlet.
Act of separating air from substances.
An informal term for a noise from an engine which indicates that it is likely to break down at any moment
The process of locating and correcting faults in a system
(dB) Unit used for measuring relative loudness of sounds. One decibel is equal to approximate difference of loudness ordinarily detectable by human ear, the range of which is about 130 decibels on scale beginning with one for faintest audible sound.
The bed of a half-ton truck.
The floor of a commercial vehicle like a bus.
The trunk lid of a car. Also called rear deck.
The upper surface of the luggage compartment.
In an engine, top face of the cylinder block on which the cylinder head mounts.
Insulated horizontal partition between refrigerated space and evaporator space. Also called coil deck
A platform in a ship corresponding to a floor in a building.
One or more boards or panels comprising the top or bottom surface of a pallet.
The process of removing the body trim or contour lines from the hood or trunk of a car, usually as part of a customized design.
The sheet metal panel extending from the bottom of the rear window to the rear panel and enclosing the cutout for the trunk lid, extending sideways to the top of both rear fenders. In some cases, this panel covers only the area between the bottom of the rear window and the front edge of the trunk lid.
A valve which is manually operated to release compression in a cylinder by allowing air to escape in order to facilitate manual starting of an old engine or a diesel engine. Some motorcycles also used a decompressor to assist in kick-starting.
A turn where the arc gets sharper as you progress through the curve
Something that is designed for a specific use or for a specific vehicle.
The volume of recoverable, salable gas reserves committed to, controlled by, or possessed by the reporting pipeline company and used for acts and services for which both the seller and the company have received certificate authorization from the Federal Energy Regulatory Commission (FERC). Reserves include both company-owned reserves (including owned gas in underground storage), reserves under contract from independent producers, and short-term and emergency supplies from the intrastate market. Gas volumes under contract from other interstate pipelines are not included as reserves, but may constitute part or all of a company’s gas supply.
A vehicle designed to operate solely on one alternative fuel, as opposed to a converted vehicle which was later altered to use an alternative fuel. Generally, dedicated vehicles provide superior emissions and performance results because their design has been optimized for operation on only one fuel. A vehicle powered by an electric motor is not to be treated as dedicated.
De Dion axle
De Dion Axle
A rear axle setup developed by Count de Dion in the 19th century in which the driving wheels are attached to curved dead axle that is attached to the frame by a central pivot, the differential unit is bolted to the frame and is connected to the driving wheels by drive axles using Universal joints. The De Dion system keeps the wheels upright (the same as a Live axle does), but Unsprung weight is reduced because the differential is out of the axle. De Dion suspension also leaves room around the differential for inboard brakes, which can further reduce Unsprung weight.
The process of discharging a battery almost completely before recharging
Forming shaped articles or shells by forcing sheet metal into a die.
Product that is stored more than one unit deep in an aisle.
Deep Link Conveyor Chain
Chain design with a carrier roller which protrudes down below the side bar but does not protrude above the side bar.
Tanks extending from the bottom or inner bottom up to or higher than the lowest deck of a ship
A device which is mounted on the outside of a vehicle and which makes a high-pitched sound to warn deer and other animals away. Whether it really works or not is debatable.
A fault in a system or a flaw in materials or a finish
A faulty condition of a vehicle with a broken mirror, missing lighting, inoperable component, etc.
A description of a component which is faulty or flawed.
(DFSC) Used by all branches of the Department of Defense (DOD)
A driving technique in which the driver prepares for and watches for the mistakes of other drivers around him so that he can avoid an accident.
Carrier returns a portion of freight charges to shipper. In exchange, shipper gives all/most shipments to carrier over specified period, usually six months. Rebate payment is deferred for similar period.
Abbreviation for Digital Electronic Fuel Injection (Cadillac)
An air chamber (like a tire or lumbar support chamber) which has lost all its air.
The loss of air from a tire or other air chamber
Deflation warning system
(DWS) developed by Dunlop for on-line detection of tire pressure loss. When tire pressure is reduced, the tire circumference is also reduced resulting in increased wheel rpm. The system uses the wheel speed sensors of an existing ABS system to continuously monitor wheel speed and tire condition, and triggers a warning signal upon detecting a problem.
The movement of a suspension piece when subjected to a load.
The amount of deformation or bending in a pallet or pallet component under load.
An electric or hot air device to remove the fog or ice from both the inside and outside of the windshield, Backlight (i.e., rear window) or even mirrors. Some are designed to remove fog from the side windows.
Device to automatically defrost evaporator. It may operate by means of a clock, door cycling mechanism, or during off portion of refrigerating cycle.
Defrosting type evaporator
Evaporator operating at such temperatures that ice and frost on surface melts off during part of operating cycle.
Device, connected into electrical circuit, which shuts unit off long enough to permit ice and frost accumulation on evaporator to melt.
The methods employed for removing methane from a coal seam that could not otherwise be removed by standard ventilation fans and thus would pose a substantial hazard to coal miners. These systems may be used prior to mining or during mining activities.
A process by which heavier crude oil fractions can be thermally decomposed under conditions of elevated temperatures and pressure to produce a mixture of lighter oils and petroleum coke. The light oils can be processed further in other refinery units to meet product specifications. The coke can be used either as a fuel or in other applications such as the manufacturing of steel or aluminum.
A barricade marking device placed on a road to prevent travel in a particular direction
To pump or discharge a liquid.
To drive a new car from the factory to the distributor or dealer. Or to drive it to the customer.
Represents the number of future years during which a pipeline company can meet its annual requirements for its presently certificated delivery capacity from presently committed sources of supply. The availability of gas from these sources of supply shall be governed by the physical capabilities of these sources to deliver gas by the terms of existing gas-purchase contracts, and by limitations imposed by State or Federal regulatory agencies.
The cost of fuel, including the invoice price of fuel, transportation charges, taxes, commissions, insurance, and expenses associated with leased or owned equipment used to transport the fuel.
The physical transfer of natural, synthetic, and/or supplemental gas from facilities operated by the responding company to facilities operated by others or to consumers.
The discharging of a liquid from a pump.
Driving a new car from the factory to the distributor or dealer
Fuel lines used to carry fuel from the fuel injection pump to the injector nozzles
Delivery mileage only
The odometer reading reflects only the distance from the factory to the selling dealer.
(DR) The control document used to deliver freight to the consignee. The delivery receipt is signed by the consignee and the driver. Also used as a receipt for collecting monies and for recording delivery exceptions.
The valve on the outlet side of a pump.
A fuel injection pump valve that rapidly decreases injection line pressure to achieve an abrupt fuel cutoff at the injector
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A model of automobile manufactured by John Z. DeLorean
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Honda Del Sol
A model of automobile manufactured by Honda
A triangular connection of the three stator windings of an alternator.
Vehicles operated by a motor vehicle dealer solely for the purpose of promoting motor vehicle sales or permitting potential purchasers to drive the vehicle for pre-purchase or pre-lease evaluation; or a vehicle that is owned and operated by a motor vehicle manufacturer or motor vehicle component manufacturer, or owned or held by a university research department, independent testing laboratory, or other such evaluation facility, solely for the purpose of evaluating the performance of such vehicles for engineering, research and development, or quality control reasons. Also called Test Vehicle
A vehicle used by a dealer for test drives and sold later at a reduced price.
A side ring or side and lock ring combination that retains the tire on the rim. It is removable to permit tire mounting or removal.
A two piece wheel rim found on trucks. The main part of the rim remains on the axle while a side piece and a locking ring is removable. In this way the whole rim is not removed from the vehicle like a passenger car’s rim and wheel. Demountable rims are still in use, though they have been replaced in many applications by the simpler disc wheel.
Multi-piece steel wheel rim assembly which is bolted to a spoke hub. Demountable rims are still in use, though they have been replaced in many applications by the simpler disc wheel. See Cast Spoke Wheel.
(DOT) The various U.S. federal agencies that regulate the operation of motor vehicles and motor vehicle equipment.
The most sharply angled incline the vehicle can leave without its rear hitting the ground. As with approach angles, it’s formed on one side by the horizontal axis, and on the other by a straight line connecting the rear edge of the rear tire and the most prominent point at the rear of the vehicle, usually the bumper or exhaust pipe.
In side view, the angle between the ground and a line, aft of the vehicle, joining the periphery of the rear wheel and (typically) the rear chassis member or other low component. It represents the size or steepness of a slope or obstacle that can be approached or climbed in reverse without striking bodywork.
Depleted storage field
A sub-surface natural geological reservoir, usually a depleted gas or oil field, used for storing natural gas.
Removal of residual magnetism thereby destroying or removing the magnetic. To remove polarity
A coating of unwanted mineral or layer of sediment at the bottom of a tank.
To apply a coating of something (often metal by electrolysis).
Abbreviation for Delivered Ex Quay (Duty Paid) with the named port of the destination. The seller fulfills his obligation to deliver when he has made the goods available to the buyer on the quay (wharf) at the named port of destination, cleared for importation. The seller has to bear all risks and costs including duties, taxes and other charges of delivering the goods thereto.
One of two guide wheels of the rear derailleur which directs the path of the chain.
The elimination of some or all regulations from a previously regulated industry or sector of an industry.
Abbreviation for Diagnostic Energy Reserve Module
A device for hoisting and lowering heavy weights, cargo, stores, etc
To remove rust from a metal part
Diesel oil when used as a fuel for road vehicles. Abbreviation for diesel-engined road vehicle
Abbreviation for Delivered Ex Ship with the named port of destination. The seller fulfills his obligation to deliver when the goods have been made available to the buyer on board the ship uncleared for import at the named port of destination. The seller has to bear all the costs and risks involved in bringing goods to the named port of destination.
The desalter mixes the hydrocarbon stream with a small amount of fresh water (e.g. 10% by volume) forming a water-in-oil emulsion. The resulting emulsion is subjected to an electric field wherein the water is coalesced as an under flow from the upper flow of a relatively water-free, continuous hydrocarbon phase. The desalted hydrocarbon stream is produced at relatively low cost and has a very small residual salt content. The performance of this unit can be improved with a demulsifier, such as Alken 860 Demulsifier.
The removal of scale or metallic oxide from metallic surfaces by pickling
The specified horsepower for a chain drive multiplied by a service factor. It is the value used to select the chain size for the drive.
Highest or most severe pressure expected during operation. Sometimes used as the calculated operating pressure plus an allowance for safety.
A man who both figures and determines what kind of deal the dealership will make to a customer.
A man who both figures and determines what kind of deal the dealership will make to a customer.
Something (like valves) which is opened and closed by a mechanical device. In most 4-stroke engines the valves are opened by the cam, but closed by the action of the valve springs. In a desmodromic system, the valves are opened by a cam and closed by a cam or a cable. A desmodromic system is more costly and more difficult to manufacture, but the advantage is more precise control of the valves and less valve bounce which is seen in a normal engine at high speed.
The removal of material which has been adsorbed. It is the opposite of Adsorption.
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A vehicle brand of which the 1956-58 Adventurer models are milestone cars.
Trucker slang for road construction as in ‘Seem’s like all the roads in Pennsylvania are always under destruction.’
The removal of sulfur, as from molten metals, petroleum oil, or flue gases.
A component for removing sulfur from a fuel mixture.
Device used to detect and locate refrigerant leaks.
Detent ball and spring
A Spring loaded ball that snaps into a groove or notch to hold some sliding object in position.
A charge made for a vehicle held by, or for, consignor or consignee for loading, unloading or for forwarding directions.
A soap-like chemical added to the engine oil (particularly MS oil) or gasoline to improve its characteristics and keep the engine clean by controlling the formation of Sludge and gum as well as controlling foaming.
Additives used to inhibit deposit formation in the fuel and intake systems in automobiles.
An MS oil which keeps the engine clean by preventing the formation of sludge and gum. It keeps particles and contaminants in suspension and has the ability to neutralize acids resulting from the combustion process.
The action of the fuel charge firing or burning too violently, almost exploding. It sometimes results in a noise called pinging. Detonation is caused by autoignition of the end gas i.e., that part of the charge not yet consumed in the normal flame-front reaction. Detonation occurs because piston motion and compression of the end gas raise its temperature and pressure to the point where the end gas autoignites. The pinging or knocking noise is the result of intense pressure waves in the charge which cause the cylinder walls to vibrate. Also called fuel knock.
A violent explosion involving high-velocity pressure waves; in a gasoline engine, the spontaneous combustion of part of the compresses charge after spark occurs. Detonation usually produces a characteristic metallic sound, or knock.
A condition where excessive temperature in the combustion chamber causes uncontrolled, explosive burning of the air-fuel mixture. As the detonated flame front collides with the flame front initiated by the spark plug, extreme pressure is often heard as pinging or knocking. Also see preignition.
Detonation-activated ignition retard
A system which retards the ignition timing when the detonation sensor picks up vibration at frequencies typical of denotation
A detection device, usually piezoelectric, mounted near the cylinders which can detect engine knocking or frequencies of detonation so that it will send a message to retard the ignition timing to prevent damage to the engine.
An alternative route which traffic has to follow due to closure of a stretch of road for repairs, etc. A diversion.
A vehicle with a reduced emission system consisting of a catalytic converter, EGR, air injection, fuel evaporative emission control, etc. Also called a controlled vehicle
The intentional adjustment of an engine to reduce its power in an attempt to reduce emissions, reduce top-end speed, increase fuel economy, or meet specific governmental standards.
Condensed atmospheric moisture deposited in small drops on cool surfaces.
To remove a coating of wax from the body of a vehicle usually in preparation for painting.
Temperature at which vapor (at 100 percent humidity) begins to condense and deposit as liquid.
A coolant that raises the boiling point and lowers the freezing point of the water in the cooling system, prevents rust and corrosion, and lubricates the system components. It is often called long-life antifreeze. It is orange in color and is designed to function up to 60 months or 240,000 Kilometres.
The analysis of the various functions of the components of a vehicle to determine if they are operating properly or have recorded faults which need to be corrected.
Diagnostic test modes
Various levels of diagnostic capabilities in OBD systems. These may include different functional states to observe signals, a base level to read diagnostic trouble codes, a monitor level which includes information on signal levels, bi-directional control with on/off board aids, and the ability to interface with remote diagnosis.
Diagnostic trouble codes
A numeric identifier for a fault condition identified by the on-board diagnostic system.
A number stored by the ECU when it detects a failure in a particular electrical circuit or mechanical system it is capable of monitoring. This number is a useful guide for repairing a problem.
A dual-circuit braking system in which each circuit brakes one front wheel and the diagonally opposite rear wheel, so that in the case of failure of one circuit reasonably balanced braking can be achieved.
A dual-circuit braking system in which each circuit brakes one front wheel and the diagonally opposite rear wheel, so that in the case of failure of one circuit reasonably balanced braking can be achieved.
A manifestation occurring off-road when a vehicle is, for example, diagonally crossing a small but well-defined ridge. When the ridge is so severe that, say, the right front wheel and the rear left wheels are on full ‘bump’ (i.e., fully up in the wheel arches) and the other wheels are hanging down to the full extent of wheel travel, the vehicle may be described as being diagonally suspended or on diagonal suspension. Some also refer to this state as being cross-axled.
The wheel-spin that can take place on the fully extended wheels in a condition of diagonal suspension. However, a vehicle need not be in a totally diagonal suspension condition for diagonal wheel-spin to take place; minor off-loading of diagonally opposed wheels or the presence of slippery ground under these wheels can provoke the condition. Can also occur crossing ditches diagonally;.
The traditional men’s bicycleframe the principal parts of which form a diamond shape.
Tubular-frame design for motorcycles common until WW II and derived from the bicycle layout. The engine cases often form part of the structure. In profile it resembles a diamond shape
The name of Chrysler Corporation which comes from the pattern of its emblem.
A flexible cloth-rubber sheet that is stretched across an area thereby separating two different compartments. A diaphragm is used in pumps to create a pressure differential that causes a fluid to be pushed or pulled from one point to another. Some carburetors have no float bowl (i.e., Tillotsen), but use a series of diaphragms to pump gasoline into the engine.
A flexible partition used to separate two chambers or elements.
In air-conditioning system, a rubber-like piston or bellows assembly which divides the inner and outer chambers of backpressure regulated air conditioning devices.
In fuel system, a thin dividing sheet or partition which separates a housing into two chambers, one of which is usually vented to vacuum while the other is not; used in vacuum-controlled secondaries, anti-stall dashpots, and other carburetor control devices.
A slightly cone-shaped metal disc with tapering fingers pointed inward or like a wavy disc, used in some clutches. In an automotive clutch, the diaphragm spring is part of the clutch pressure plate. When the clutch is engaged, this spring is flattened and forces the pressure plate against the clutch disc; driver effort through the clutch linkage overcomes the spring pressure to disengage it.
The separate individual cutting teeth units mounted in a large die head. Usually four or more units are installed. Some dies have these chasers permanently mounted while others are replaceable. The chaser cuts the external screw threads and is used to clean up damaged threads.
A material which is an electrical insulator or in which an electric field can be sustained with a minimum loss of power.
Fluid with high electrical resistance.
A special grease which is applied to the ends of electric terminals to inhibit corrosion between the terminals or to be sure that there is good electrical contact between the terminals.
Dielectric silicone compound
A non-conducting silicone grease applied to spark plug wire boots, rotors, and connectors to prevent arcing and moisture from entering a connector
The master model, traditionally hand carved from mahogany that served as the final, correct guide for making sheetmetal stamping dies.
A type of engine or fuel or oil used for that engine.
A four-stroke cycle where the air is sucked into the cylinder and compressed at a ratio of up to 241. At the end of the compression stroke the fuel is injected. Because of the high compression and resulting increase in temperature, the fuel is ignited leading to the power stroke and followed by the exhaust stroke where the combustion products are removed.
A generating station that uses diesel engines to drive its electric generators.
A light oil fuel which has a relatively low ignition temperature. It is heavier than gasoline and uses the heat of extremely highly compressed air to ignite the fuel in the combustion chamber.
A fuel composed of distillates obtained in petroleum refining operation or blends of such distillates with residual oil used in motor vehicles. The boiling point and specific gravity are higher for diesel fuels than for gasoline.
Diesel engines are internal combustion engines that burn diesel oil rather than gasoline. Injectors are used to spray droplets of diesel oil into the combustion chambers, at or near the top of the compression stroke. Ignition follows due to the very high temperature of the compressed intake air, or to the use of Glow plugs, which retain heat from previous ignitions (spark plugs are not used). Diesel engines are generally more fuel-efficient than gasoline engines but must be stronger and heavier because of high compression ratios.
Product of the API gravity and the Aniline point (in degrees Fahrenheit) of a Diesel fuel, divided by 100; an indication of the ignition quality of the fuel.
A form of autoignition in which a gasoline engine continues to fire after the ignition has been shut off. In late-model emission-controlled engines, dieseling or run-on is caused by heat and the unusually high Manifold pressure that result from retarding the spark at idle.
The noise caused by the rapid rise in pressure in a diesel engine especially when the engine is cold or running at a low speed. Also called diesel rattle.
(DOC) Catalyst promoting oxidation processes in diesel exhaust. Usually designed to reduce emissions of the organic fraction of diesel particulates, gas-phase hydrocarbons, and carbon monoxide.
Diesel particulate filter
(DPF) A filter which removes small particles from a diesel exhaust. It looks like a honeycomb catalytic converter but acts as a mechanical separator. It prevents these particles from discharging in the tailpipe. Collected particulates need to be removed from the filter, usually by continuous or periodic oxidation in a process called regeneration.
Diesel Particulate Matter
(DPM) Sub-micron size particles found in diesel exhaust. Most emission regulations specify DPM measurement methods in which particulates are sampled on filters from cooled exhaust gas. The cooling causes condensation of vapors in the gas sampling train. Thus, the DPM is composed of both solid and liquid particles and is generally classified into three fractions:
inorganic carbon (soot)
organic fraction (often referred to as SOF or VOF)
A tool used to hold and operate dies when cutting outside threads.
Retread rubber is designated by its crescent shaped dimensions in inches and eighths, and its thickness in 32nds of an inch; (e.g., 66-72-16; the crown would measure 6 and 6 eighths, the base 7 and 2 eighths wide; and the thickness 16/32 of an inch, or gauge of the stock rubber.)
Locking mechanism of the center differential on a four-wheel drive vehicle. In some vehicles, activation is made by moving the shift lever, by activating a separate lever, or by engaging a button (usually on the shift lever). Once engaged, the ‘DIFF-LOCK’ light on the instrument panel is illuminated. Engaging the diff-lock causes all four wheels to rotate alike giving good traction on slippery terrain. When the vehicle is driven on pavement, the center differential should be unlocked so that the front and rear differentials can permit the wheels to turn independently of each other as required, for instance, when turning a corner.
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Amount added to or deducted from the base rate to make the rate to or from some other point or via another route.
The temperature or pressure difference between cut-in and cut-out temperature or pressure of a control.
A unit on rear-wheel drive vehicles that takes the power of the rotating driveshaft at right angles to the rear axle and passes it to the axle. It will not only drive both rear axles at the same time, but will also allow them to turn at different speeds when negotiating turns. In this way the tires do not scuff or Skid
In front-wheel drive cars, the differential is located in the transaxle, usually directly below the transmission.
A mechanism that allows torque to be applied to two different gears that can turn at different speeds. In negotiating a corner, the outside wheel of a car must travel farther than the inside wheel in the same amount of time.
The pressure difference between two regions, such as between the intake manifold and the atmospheric pressures. In Bosch KE-Jetronic systems, the difference between actuator fuel pressure in the lower chambers of the differential-pressure valves and the system pressure entering the pressure actuator.
The difference in pressure between the upper and lower chambers of a CIS fuel distributor
An electronically controlled valve which regulates the fuel flow to the lower chamber of the CIS fuel distributor
Differential pressure valve
Inside the Bosch CIS fuel distributor, these valves (there is one for each cylinder) maintain a constant pressure drop at each of the control-plunger slits, regardless of changes in the quantity of fuel flow
Differential pressure warning switch assembly
A unit to actuate a warning device indicating an undesirable pressure difference between the separate circuits of a brake system
The lens in the headlight glass which helps to focus the beam
The way in which innovations spread through market or non-market channels.
Mixing the molecules of two gases by thermal agitation
Movement of a species under the influence of a gradient of chemical potential (i.e. a concentration gradient).
Method of monitoring local air quality.
The process by which particles of liquids or gases move from an area of higher concentration to an area of lower concentration.
VW collaborated with Bosch to develop this electronic injection system. Digifant is similar to a Motronic system, except that its timing control map is less complicated than the Motronic map. And it does not have a knock sensor
A refined version of VW ‘s digifant. This system has some control improvements and uses a knock sensor for improved timing control
A signal that is either on or off. In a computer, the signal is translated into binary digits 0 and 1 and is interpreted by the microprocessor as a voltage signal that is either low or high, or current flow that is on or off.
A slide-type caliper which gives a digital readout.
A timing piece which reveals the time with a series of numbers rather than with sweeping pointers.
A computer that works with information in the form of fixed numbers, usually in binary code.
Instrument display that uses a liquid crystal display (LCD) for engine and vehicle speed as well as other indicators. Contrast Analog display
Electrical filter suitable for use with digital signals, i.e., those which are continuous with time. Contrast with Analog filter.
Digital frequency control
(DFC) A system which automatically stabilizes or tunes the frequency of a selected radio station.
Digital fuel injection
(DFI) a GM system, similar to earlier electronic fuel injection system, but with digital microprocessors. Analog inputs from various engine sensors are converted to digital signals before processing. The system is self-monitoring and self-diagnosing. It also has the capabilities of compensating for failed components and remembering intermittent failures
A measuring tool which displays information in a digital format. Digital displays can use liquid crystal display (LCD), light-emitting diode(LED), etc.
Digital ratio adapter controller module
(DRAC) a device used on GM vehicles to convert the analog signal from the speed sensor into a digital signal that the EBCM can use
A speedometer which shows the speed in digital numbers rather than a needle on a dial gauge (which is called an analog speedometer).
Digital volt-ohm multimeter
(DVOM) a digital electronic meter that displays voltage and resistance
A rotary control switch which will increase or decrease the intensity of the instrument lights. Also called interior dimmer light switch.
A vehicle mirror located within the passenger compartment above the windshield which can be switched to reduce the glare from the headlights of a vehicle approaching from behind. Some are activated automatically while others are engaged by a lever below the mirror.
A device used to lower or increase the brightness and focus of the headlights (i.e., from high-beam to low-beam). The British term is dipswitch. Also called Headlight dimmer switch
Abbreviation for Deutsche Industrie Normen (German industrial standards). DIN horsepower is similar to the SAE net horsepower. It is measured at the Output shaft of an engine fully equipped with normal accessories.
A small dent in the surface of a panel
The action of straightening a damaged panel by using a hammer and dolly to bring it back into shape.
A colloquial term for a person who repairs body panels. A person who works in an automotive factory adjusting panels without damaging the paint
The standard hole in the instrument panel through which a DIN radio can be installed
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A model of automobile manufactured by Ferrari
A registered trade name by 3M for a thin, highly flexible, stretchable, paintable plastic film used to cover clay models to give them color and gloss. Di-Noc can be painted after adding an elasticizer. Painted, it’s usually soaked in a hot-water solution to make it pliable. The name Di-Noc also refers to an ornamental film used in the 1930’s through the early 1950’s to bond woodgrain and other ornamental patterns to garnish moldings, instrument panels, station-wagon exteriors, etc.
An aftermarket radio which fits into a thinner hole than most American radios. When installing a replacement radio, special faceplates are necessary
Two-element electron tube which will allow more electron flow in one direction in a circuit than in the other direction; tube which serves as a rectifier.
An electrical component having the ability to pass electric current readily in one direction but resisting current flow in the other. When four diodes are connected in a certain way (i.e., bridged) they will convert AC to DC, thus becoming a rectifier.
The metal rod that passes into the oil sump it is used to determine the quantity of oil in the engine. The oil level is marked on the rod and matches level indicators on the rod. Dipsticks are used to check engine oil and Transmission fluid. In most instances, the dipstick is inserted as far as it will go and then removed to check the level. In motorcycle engines, the dipstick is placed on the top of the threads (i.e., not screwed down) to check the level.
A stick that’s dipped into a reservoir to check the level of the fluids based on the markings on the stick. Most common dipsticks are for used to check oil, transmission fluid, and power steering fluid.
An oil injection system which feeds undiluted oil to two-stroke engine main bearings and rod big-end bearings.
(DC) An electric current that flows steadily in one direction only. This is the type of current found in a battery and throughout the lighting and accessory system of a vehicle. Contrasts with Alternating current (AC).
Direct current motor
An electric motor which is energized by direct-current to provide torque. There are several classes of direct-current motors. The designer chooses the type to yield the desired characteristics.
A vehicle damage caused directly by an impact with an object. In contrast with an indirect damage.
Direct digital control
(DDC) Use of digital computer to perform required automatic control operations in a total energy management system.
In diesel engines with direct injection the combustion chamber is not divided and fuel is injected directly to the cylinder.
Direct ignition device
An igniter used to ignite gas at a main burner.
Direct ignition system
An ignition system which does not used a distributor but carries high voltage from the ignition coils directly to the spark plugs.
A system in which the ignition means functions to ignite the main burner gas directly and in which a flame sensing means or safety shutoff device senses main burner flames or the absence of main burner flames.
A fuel injection system which is generally used in diesel engines and forces fuel directly into the combustion chamber. It requires very high injection system pressure to overcome the pressure within the combustion chamber.
Production of a desired product (hydrogen) within a fuel cell from a hydrocarbon based fuel (methanol, gasoline, etc.) fed to the fuel cell or stack.
Directional baffle plate
Installed in a Quadrajet carburetor’s secondary bores to help direct the airflow for improved distribution in the intake manifold
Ability of a vehicle to move forward in a straight line with a minimum of driver control. A vehicle with good directional stability will not be unduly affected by side wind, road irregularities, etc.
Directional designs are recognized by the grooves in the tread that swipe away in a backward angle from the center of the tread face and rotate in only one direction. A direction of rotation arrow is located on both sidewalls of the tire. Directional tires enhance straight-line acceleration, provide maximum dry traction, better wet performance which helps to reduce rolling resistance as well as providing shorter stopping distances.
The signal lights which blink on either side of the front of the vehicle and either side of the rear of the vehicle. Some early cars (like the Austin and Flying Standard) had small illuminated arms that flipped out from the B-post instead. The purpose of signal lights is to warn other drivers of a change in direction when turning a corner or changing lanes.
Direction indicator warning light
A light on the instrument panel which flashes when the signal lights are operating. Usually this light is in the shape of a green arrow. On some cars, like Cadillac, a secondary light is mounted in a pod on the upper edge of each front fender and in a pod inside the cab above the backlight (i.e., back window)
Direction of rotation
The direction in which a wheel or shaft turns or is supposed to turn.
Direction of travel
The direction in which an object (e.g., a vehicle) is moving.
Loading of shipments directly from one service center to another without an intermediate stop for rehandling.
Direct methanol fuel cell
(DMFC) A type of fuel cell in which the fuel is methanol (CH3OH), in gaseous or liquid form. The methanol is oxidized directly at the anode with no reformation to hydrogen. The electrolyte is typically a PEM.
Direct current flowing from anode (base metal) to cathode (electrode). The electrode is negative and the base metal is positive.
A type of a very powerful centerpull bicycle brake used mostly on mountain bikes from the 1980s and early 1990s
A motorcycle intended for off-road use that are not legal to ride on public roads. Sometimes the term pure-dirt is used to distinguish a dirtbike from a dual-sport motorcycle
Trucker slang for New York City as in ‘I got a load of garbage going to dirty town.’
An abbreviation for Direct ignition system or a distributorless ignition system similar to the C3I system, using two coils on four-cylinder engines
Abbreviation for Direct Ignition (Waste Spark)
The condition of a vehicle which is not able to be driven because of a failure of some component (e.g., bad battery, flat tire, engine seized) or because of an accident.
The diameter at which a worn brake drum should be replaced
The largest inside diameter at which a brake drum can safely operate.
The thickness at which a brake disc should be replaced
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A type of brake that has two basic components a flat rotor (disc) that turns with the wheel and a caliper that is stationary. When the brake pedal is depressed, linkage (mechanical or hydraulic) causes the caliper to force its heat-resistant brake pads against both sides of the rotating disc thus slowing or stopping the wheel. Almost all new cars have disc brakes on the front wheels with drum brakes on the rear. More expensive cars have four wheel disc brakes. Because of the need for greater pressure to activate disc brakes, most cars so equipped also have a power Booster. Wear takes place in the pads and the rotors. The pads are usually replaced while the rotors can sometimes be reground else they too must be replaced. If the rotors are not tightened correctly when installed, they can warp and cause a jerking motion when stopping.
The pressure exerted in a liquid pumped, expressed in psi.
The (high side) pressure of the refrigerant being discharged from the air conditioner compressor
Amount of current discharged from a battery, expressed in amps
The part of the air conditioner system under high pressure, extending from the compressor outlet to the thermostatic expansion valve/tube inlet
Solderless connectors in male and female forms, intended to be easily disconnected and connected. Typically, a blad or pin (male connector) fits into a matching receptacle or socket (female connector). Many components have built-in (blade) terminals that require a specialized female connector.
Valve on the outlet side of a reciprocating pump. The opposite is suction valve.
In an air conditioner system, a device used to check high side pressures, usually referred to as the high side service valve
A device used to check high side pressures. Usually referred to as the high side service valve
Current supplied by a storage cell or battery, whose direction is opposite to that of the charging current
To alter the color of (a finish, metal, etc.) to a color which is not wanted. This fading may be caused by sitting in the sun, drops of contaminants (tree sap, bird dropping, spilled gasoline), poor paintwork, etc.
To remove the terminal from a mechanical or electrical device or from the other side of the terminal. While some may be simply pulled apart, others have catches which must first be released.
Solderless connectors in male and female forms, intended to be easily disconnected and connected. Typically, a blade or pin (male connector) fits into a matching receptacle or socket (female connector). Many components have built-in (blade) terminals that require a specialized female connector
Disconnect the battery
The action of removing the high tension electrical cables from the battery terminals. Also called isolate the battery
A variety of small or large disfigurations on an object such as pits, tool marks, voids, overlaps, folds, seams, and inclusions.
A rim and metal disc that have been welded together. The disc is usually offset from the centerline of the rim to allow for dual tire mounting and to provide sufficient clearance between the duals. Disc wheels are attached to the hub with either single nuts or double cap nuts.
Single-piece rim/wheel assembly of stamped and welded steel or forged aluminum, anchored by 8 or 10 nuts to a hub.
A steel wheel whose center is stamped on one piece.
To move (a gear, dog clutch, etc.) so that it no longer meshes with another matching part
Disengage the clutch
During normal driving, the power of the engine is being transferred to the gears of a manual transmission because the clutch plates are pressed together. When you press down on the clutch pedal (or pull in the clutch lever on a motorcycle), you are releasing that contact (i.e., disengaging the clutch) so that there is no connection between the engine and the transmission. You engage the clutch when you release the pedal or lever.
A depression in the top of a piston.
Offsetting of the hub on a rear wheel on a derailleur bike to make room for the freewheel and still allow the wheel to be centered within the frame.
A vehicle taxation system which determines the amount of taxes based on the engine displacement of the vehicle.
That part of the cylinder capacity that is swept by the pistons on their up and down strokes (i.e., the volume through which a piston moves in one stroke) formed by the bore diameter and the piston stroke. Also called swept volume.
Any device that conveys information. In a vehicle, displays are either lights, gauges, or buzzers. Gauges may be analog or digital
A fee you pay at the end of the lease, to the lessor, that covers the lessor’s cost of getting the vehicle ready for sale after you have returned the vehicle. It is often applied against any deposit you made at lease inception.
A general classification for one of the petroleum fractions produced in conventional distillation operations. It includes diesel fuels and fuel oils. Products known as No. 1, No. 2, and No. 4 diesel fuel are used in on-highway diesel engines, such as those in trucks and automobiles, as well as off-highway engines, such as those in railroad locomotives and agricultural machinery. Products known as No. 1, No. 2, and No. 4 fuel oils are used primarily for space heating and electric power generation.
No. 1 Distillate: A light petroleum distillate that can be used as either a diesel fuel (see No. 1 Diesel Fuel) or a fuel oil. See No. 1 Fuel Oil.
No. 1 Diesel Fuel: A light distillate fuel oil that has distillation temperatures of 288°C at the 90-percent point and meets the specifications defined in ASTM Specification D 975. It is used in high-speed diesel engines, such as those in city buses and similar vehicles.
No. 1 Fuel Oil: A light distillate fuel oil that has distillation temperatures of 204°C at the 10-percent recovery point and 288°C at the 90-percent point and meets the specifications defined in ASTM Specification D 396. It is used primarily as fuel for portable outdoor stoves and portable outdoor heaters.
No. 2 Distillate: A petroleum distillate that can be used as either a diesel fuel or a fuel oil.
No. 2 Diesel Fuel: A fuel that has distillation temperatures of 260°C at the 10-percent recovery point and 338°C at the 90-percent recovery point and meets the specifications defined in ASTM Specification D 975. It is used in high-speed diesel engines, such as those in railroad locomotives, trucks, and automobiles.
Low Sulfur No. 2 Diesel Fuel: No. 2 diesel fuel that has a sulfur level no higher than 0.05 percent by weight. It is used primarily in motor vehicle diesel engines for on-highway use.
High Sulfur No. 2 Diesel Fuel: No. 2 diesel fuel that has a sulfur level above 0.05 percent by weight.
No. 2 Fuel oil (Heating Oil): A distillate fuel oil that has distillation temperatures of 204°C at the 10-percent recovery point and 338°C at the 90-percent recovery point and meets the specifications defined in ASTM Specification D 396. It is used in atomizing type burners for domestic heating or for moderate capacity commercial/industrial burner units.
No. 4 Fuel: A distillate fuel oil made by blending distillate fuel oil and residual fuel oil stocks. It conforms with ASTM Specification D 396 or Federal Specification VV-F-815C and is used extensively in industrial plants and in commercial burner installations that are not equipped with preheating facilities. It also includes No. 4 diesel fuel used for low- and medium-speed diesel engines and conforms to ASTM Specification D 975.
Gasoline contains various hydrocarbons that boil at different temperatures. As a result, the gasoline boiling range can extend from 27°C to a maximum of 225°C. This is in contrast to water that boils only at 100°C at sea level.
The process of heating a liquid to its boiling point and condensing and collecting the vapors
Distribution Centers are warehouse facilities that store, manage, and ship inventory on behalf of its clients. Inbound carriers bring product into the Distribution Center. Product can be immediately allocated to existing orders, or it can be placed into storage for the purpose of filling future orders. Outbound carriers transport stock from the Distribution Center to the end user. Distribution Centers are strategically placed close to major transportation lanes (i.e., highways, railroads). They rely on outside carriers as well its own fleet of trucks to transport product.
The path goods take as their title transfers from producer to consumer. The title transfer for consumer goods is usually accompanied by transfer of the physical goods, as well.
Systems which help evenly and efficiently transfer the heating or cooling medium to the area where it is needed.
A calculation of the emf in the windings of an ac motor while taking into account that each coil is not in phase with the other coils.
Tubes used in the engine cooling area to guide and direct the flow of coolant to vital areas.
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A unit in the ignition system designed to make and break the ignition Primary circuit and to distribute the resultant high voltage to the proper cylinder at the correct time. The high voltage comes from the coil to the center terminal of the distributor cap and passes down the rotor. As the rotor turns, contact is made with each successive terminal on the circumference of the distributor cap. From there, the voltage goes into the spark plug wires and to the spark plug. Generally when your vehicle has its timing adjusted, it is the distributor that is adjusted. Also called ignition distributor.
A distributor performs many of the same functions as wholesalers such as selling, physical distribution, credit, etc.; but is between the dealer and the wholesaler. Some industries use the term distributor instead of wholesaler.
A company primarily engaged in the sale and delivery of natural and/or supplemental gas directly to consumers through a system of mains.
The fixed plate in the body of the distributor on which the contact breaker or triggering device is mounted, and through the center of which the distributor shaft passes
The bowl-like part containing the distributor shaft with the rotor arm at its top end, and, in the conventional version, the centrifugal advance mechanism and the contact breaker
The cam at the top of the distributor shaft with as many lobes as there are cylinders, acting on the heel of the contact breaker arm
An insulated cover containing a central terminal or tower with a series (one per cylinder) of terminals or towers that are evenly spaced in a circular pattern around the central terminal or tower, the secondary voltage travels to the central terminal or tower where it is then channeled to one of the outer terminals or towers by the rotor. The cap also keeps dirt and moisture out of the distributor.
A fuel injection pump using pistons which pressurizes fuel for injection in the proper cylinder based on the relative port position of the rotating shaft in the hydraulic head
Distributorless ignition system
(DIS or DLS) An electronic ignition system that does not have a conventional rotating distributor. Instead, it uses multi-spark ignition coils or one ignition coil for each spark plug.
A pipe or tube through which the fuel travels from the fuel distributor to the injection nozzle
A rotating part of the distributor which transfers high voltage to each spark plug. In a distributors with points, it is oblong-shaped; but in a distributors without points, it is usually a disc. Also called a rotor or rotor arm.
The metal shaft inside the distributor that has a cam wheel which revolves with the shaft and forces the points to open. A spring causes the points to close. The distributor rotor is mounted on the top of this shaft.
The terminals at the top of the distributor cap into which the spark plug wires fit. Also called terminal tower
One of two flat pieces of metal found inside the distributor’s centrifugal advance mechanism on the baseplate. They swing out as speed increases and consequently advances the timing of the spark.
A special tool used to tighten or loosen the distributor hold down clamp when installing or removing a distributor
District heating and cooling
Use of a central utility system designed to provide heating and cooling to large residential and industrial areas.
An open channel for the passage of waste water along the side of the road
Moving apart. For example, traffic taking a right turn when other traffic is moving straight ahead or traffic leaving a motorway.
In today’s market, especially in smaller centers, a dealership cannot make a profit on just one brand of vehicle — especially foreign imports. Thus the dealership will diversify by having several brands (e.g., Mercedes-Benz, BMW, and Mazda). A car manufacturer diversifies by making several different kinds of vehicles (trucks, vans, luxury cars, family-size cars, commuter cars, compacts, convertibles, sports cars, etc.) in an attempt to reach every segment of the population. Some dealers or manufacturers may diversify by offering lawnmowers, boat motors, and motorcycles as well as automobiles (e.g., Honda) or even musical instruments (e.g.,Yamaha).
An alternative route which traffic has to follow due to closure of a stretch of road for repairs, etc. A detour.
A change made in consignee, destination, or shipment route while in transit.
To cause (air, a liquid, traffic, etc.) to follow a different course. For example, air is diverted to the air cleaner; traffic has been diverted around the accident site.
A high volume highway with a median that separates lanes of traffic going in opposite directions. Usually two or more lanes in each direction. Called dual carriageway in the U.K.
Divided propeller shaft
A propeller shaft, usually in long chassis rear-wheel drive vehicles, which is divided into two sections with a bearing and CV joint mounted on a chassis crossmember at the central point. Also called divided propshaft
A propeller shaft, usually in long chassis rear-wheel drive vehicles, which is divided into two sections with a bearing and CV joint mounted on a chassis crossmember at the central point. Also called divided propeller shaft
A measuring tool with two straight pointed arms used to mark off and transfer measurements, e.g., on sheet metal or other metal components.
Vacuum diaphragm is mounted on the carburetor, but the bimetal spring is mounted either on a pad on the intake manifold or in a heat well in the exhaust man. Choke lever is operated by a mechanical linkage rod from the bimetal spring. Also called a Remote choke
A person, whether qualified or not, who does his own repairs on his own vehicle.
Term used by Bosch to describe a fuel injection system controlled by manifold pressure. The D is short for druck, the German word for pressure. Manifold pressure is measured to indicate engine load (how much air the engine is using.) This pressure is an input signal to the control unit (ECU) for calculation of the correct amount of fuel delivery
In 1904 Jörgen Skafte Rasmussen set up on his own as a manufacturer of boiler fittings. In 1906 he purchased a textile mill in Zschopau, Saxony. Production started there in 1907. During the First World War Rasmussen worked on a steam-driven vehicle (Dampfkraftwagen), from which the three letters DKW were derived. In 1922 the company Zschopauer Motorenwerke started manufacturing its own motorcycles. The sporting successes of the lightweight motorcycles with 2.25 hp two-stroke engine were remarkable. Victories in the Berlin Avus race in 1922 and the triple victory by the DKW team in the ADAC Reichsfahrt the same year made people sit up and take notice. The first DKW motorcycle was consequently called the Reichsfahrt. Over the next six years Zschopauer Motorenwerke/DKW established itself as the world’s biggest motorcycle manufacturer. Rasmussen finally had access to a powerful engine for the DKW car (600 cc, 15 hp) in the form of the two-cylinder motorcycle unit (1927). The vehicle, which had a load-bearing body covered in imitation leather, had rear-wheel drive. It was produced in the Spandau district of Berlin from 1928.
An abbreviation for deluxe which is usually applied to a series of vehicles which is one step up from custom
A formal record of a Federal Energy Regulatory Commission proceeding. These records are available for inspection and copying by the public. Each individual case proceeding is identified by an assigned number.
Outer wall of dock door.
A plate at the dock door entrance that raised and lowered either manually or hydraulically to accommodate trailer floor heights.
A light used to illuminate the inside of a trailer in order to aid in the loading and unloading processes.
A moveable metal plate used as a ramp or bridge that is placed between the warehouse dock door and a trailer or railcar and makes it easier/smoother to access a trailer or railcar with a forklift or similar equipment.
A qualitative method of detecting undesirable sulfur compounds (i.e., H2S) in petroleum distillates, that is, of determining whether oil is Sour or Sweet.
A vehicle in very bad shape, which may not be man’s best friend.
A lug or protrusion on an object.
A knob on the side of a gear that aligns or interlocks with a matching dog or hole in an adjacent gear.
A small bent metal fitting used in closing doors, hatch covers, manhole covers, etc.; a bent bar of round iron used in holding shapes on bending slab; any small flat lug temporarily welded to structure as backing for a wedge.
A simple coupling with two halves called dogs, with square projections in one that engage in square slots in the other to transmit drive, but can also be disengaged to break the drive.
Mating collars, flanges, or lugs which can be moved as desired to engage or disengage similar collars, flanges, or lugs in order to transmit rotary motion
A grid made of tubular bars or wire mesh to keep a dog in the back part of a vehicle
An angled bend, often at the trailing edge of a window; also where the rear door curves around the rear wheelhouse of a four-door body style.
The angle created at the door opening by the wrap-around windshields found on many mid to late ’50’s models.
The C-post or C-pillar.
An irregular shaped part of the leading edge of the rear quarter panel of a four-door sedan along the wheel cutout and up to the waistline
A cylindrical extension, or pilot, of diameter smaller than the minor diameter of the thread, commonly equal to about D/2 in length, with a conical section between it and the thread; usually used as a pilot in assembling or as the end of a set screw projecting into a fairly deep hole or slot.
Trucker slang for Speed up as in ‘Now that we’re on the boulevard lets do it to it.’
(DIY) The vehicle maintenance and repairs conducted by the vehicle owner or friend/relative who purchase auto parts from a retail outlet.
A person, whether qualified or not, who does his own repairs on his own vehicle.
Abbreviation for Data Output Line to IPC
A metalworking tool, available in a variety of shapes and sizes, comprising a curved polished block of cast iron or forged steel, used to assist in forming three-dimensional shapes and in straightening dented panels, usually by holding the dolly behind the metal to be shaped and hammering the metal.
A small two-wheeled non-motorized trolley or hand trukck for moving heavy objects.
A trolley that supports the front wheels or back wheels of a disabled vehicle for towing it.
A single-axle piece of trailing equipment used to hook two trailers together.
Sealed metal container for the motor compressor of a refrigerating unit.
A dome-shaped interior light. Also called a dome light.
A dome-shaped interior light. Also called a dome light.
A vehicle produced in Canada, United States, or Mexico. The opposite is foreign.
As defined by the Energy Policy Act, Section 301, domestic fuel is derived from resources within the United States, its possessions and commonwealths, and Canada and Mexico (the two nations in a free-trade agreement with the U.S.).
Domestic vehicle producer
An original vehicle manufacturer that assembles vehicles in North America (U.S.A., Canada, or Mexico) for domestic use.
A car from which parts are used to repair another one of the same type or to build a special or kit car
Do not enter
Do not enter
A sign indicating that travel is not permitted down a certain road or in that direction
The hinged side panels of a vehicle which permit the occupants to enter or leave the passenger compartment. In most cases the doors open so that the hinge is toward the front of the vehicle. When the hinge is toward the back of the vehicle, they are called Suicide doors.
The pivoting part which is attached to the door frame and the door pillar. It allows the door to swing open or shut.
Door hold-open spring
A spring attached to the door hinge to provide a spring load to keep the door in an open position
That part of the door lock which contacts the striker plate as the door is closed, and springs back when the door is fully shut to hold it in the closed position
A mechanism for allowing a door to be opened either by the operation of a key on the outside of the door or by releasing a mechanical switch on the inside of the door.
Door lock de-icer
A fluid which is inserted into the key-hole to melt the ice which has bound the tumblers in a door lock.
An exterior, door mounted, rear-view mirror. On trucks and older vehicles the mirror is manually adjusted; but on many cars they are adjusted either by a cable inside the cab or by an electric motor with the switch inside the cab. The control device is located on the door, on the instrument panel, or on the console between the driver and passenger.
The door inner trim panel
A panel covered in vinyl or other material and mounted to the inside of the door
One of the vertical members of the body shell ahead of and behind the doors, which also support the roof structure and reinforce the body as a whole
Door pillar switch
A small switch, typically in the lower portion of the A-pillar, whose main function is to turn on the courtesy lights when the door is opened and to indicate that the door is open especially if the key is left in the door.
A container or pouch located on the lower inside portion of the door. It can be used to store maps and other small items
One of the vertical members of the body shell ahead of and behind the doors, which also support the roof structure and reinforce the body as a whole
A strip of rubber, plastic, or chrome which fits over the edge of the door to protect it from damage when opened carelessly
A handle on the inside of a vehicle door which allows the driver/passenger to pull his door shut
The hourly rates charged by dealers on standardized units of service work. Hourly rates may or may not correspond to an actual hour of work.
A weatherstrip surrounding the door to form a seal when the door is closed
The edges of a door which are not visible from the outside or inside when the door is shut. Also called door face.
The bottom part of the door frame (i.e., the pat under the door when it is closed).
The large sheet metal panel of the door visible from the outside. Available to body shops as a replacement panel for most cars
Radio/stereo speakers mounted in the door panel
A device incorporated in door hinges that keeps the door in an open position and prevents it from closing under its own weight
Top part of the outer sill, visible when the door is opened
The faces of the door step, door pillars, and roof section which makes up the door aperture
A panel covered in vinyl or other material and mounted to the inside of the door
Door trim pad
The covering used to conceal the lower portion of the inside panel of the door.
A cavity enclosed by the door frame, door skin, and trim panel containing the window winding mechanism and into which the window glass is lowered
Abbreviation for the U.S. Department of Transportation — an American federal agency
Abbreviation of Department of Transport — a British agency
The department in each state usually responsible for the state’s road network. The name differs between states.
This brake fluid has a glycol base. It is clear or light amber in color. Its Dry boiling point is 205°C minimum and Wet boiling point of 140°C minimum. It will absorb 1 to 2 percent of water per year depending on climate and operating conditions. It is used in most domestic cars and light trucks in normal driving. It does not require cleaning the system and it can be mixed with DOT 4 and DOT 5.1 without damage to the system. The problem with it is that it absorbs moisture out of the air and thereby reduces its Boiling point. It can also damage the paint on a vehicle.
This brake fluid has a borate ester base. It is clear or light amber in color. Its Dry boiling point is 230°C minimum and Wet boiling point of 155°C minimum. It is used in many European cars; also for vehicles in high-altitude, towing, or high-speed braking situations, or ABS systems. It does not require cleaning the system and it can be mixed with DOT 3 without damage to the system. The problem with it is that it absorbs moisture out of the air and thereby reduces its Boiling point. It can also damage the paint on a vehicle.
This brake fluid generally has a silicone base. It is violet in color. Its Dry boiling point is 260°C minimum and has no Wet boiling point in federal DOT 5 Specifications. It is used in heavy brake applications, and good for weekend, antique, or collector cars that sit for long periods and are never driven far. It does not mix with DOT 3, DOT 4, or DOT 5.1. It will not absorb water and will not damage the paint on a vehicle. It is also compatible with most rubber formulations. The problem with it is that it may easily get air bubbles into the system which are nearly impossible to remove, giving poor pedal feel. It is unsuitable for racing due to compressibility under high temperatures. If as little as one drop of water enters the fluid, severe localized corrosion, freezing, or Gassing may occur. This can happen because water is heavier and not mixable with silicone fluids. It is unsuitable for ABS.
This brake fluid has a borate ester base. It is clear or light amber in color. Its Dry boiling point is 260°C minimum and Wet boiling point of 180°C minimum. It is used in severe-duty vehicles such as fleets and delivery trucks; towing vehicles, and race cars. It can be mixed with DOT 3 or DOT 4 without damage to the system. It maintains higher Boiling point than DOT 3 or DOT 4 fluids due to its higher borate ester content. It is excellent for severe duty applications. The problem with it is that it costs more than other fluids and there is limited availability. It also absorbs moisture out of the air and thereby reduces its Boiling point. It can also damage the paint on a vehicle.
The symbol DOT on a tire means it meets or exceeds Department of Transportation safety standards. Following DOT are a maximum of eleven numbers. E.g., DOT FT TW A2NX 092. (DOT = meets or exceeds federal standards; FT = identifies manufacturing plant; TW = the code for tire size; A2N or A2NX-3 or optional four digits = manufacturer’s code to identify the characteristics of the tire; 092 = Week of mfg., in this case, 9th week of 1972. Prior to May 22, 1971 the manufacturer’s plant was identified by only three numbers (Example DOT 129). Retreaded tires must also have a new serial number and can be determined by the letter R following DOT letters.
A combination of a tractor and two semitrailers connected in tandem by a converter dolly. Also called Twins or Twin Trailers
A suspension system which has two triangular (A-shaped) control arms as the main support of the wheel. The wide ends of both upper and lower A-arms are hinged to the frame. The narrow ends are attached to the upper and lower ball joints. The steering knuckle (including the stub axle or spindle that carries the wheel bearing and the wheel) is fixed between these ball joints. This configuration allows the wheel to move up and down with variations in the road surface and left and right as it is steered, while keeping the wheel in the correct position with respect to the road and the vehicle. A spring and a shock absorber are set between the frame and the lower A-arm (shown in image), or between the frame and the upper A-arm, to absorb road shock and to help control wheel movements.
(of a shock absorber or pump) having a piston with fluid on both sides so that in a pump one piston end performs the suction stroke while the other discharges the liquid, and in a shock absorber both upward and downward movements are damped
Vehicles with manual transmission and no Synchromesh have difficulty shifting from one gear to another. With synchromesh, shifting is accomplished by depressing the Clutch pedal and moving the Gearshift selector from one gear to the next. Without synchromesh, shifting is not smooth unless you double clutch. Here you depress the Clutch pedal shift to neutral lift up on the Clutch pedal blip the throttle (accelerator), then depress the Clutch pedal again and shift to the next gear. While this action seems complicated, you can get used to doing it to avoid the grinding noise heard in non-synchromesh transmissions.
Two single coats of primer or paint applied with little or no flash time between them.
A drum brake having two leading shoes and no trailing shoes. Each shoe has its own activating cam and pivot.
Trucker slang for Traveling at 55 MPH as in ‘I sure got tired of running the double nickle.’
Double overhead cam
Click to supersize
Double Overhead Cam
(DOHC) An engine with two camshafts located above the cylinders. One drives the intake valves and the other operates the exhaust valve. In a single overhead cam engine (SOHC), one cam has enough lobes to drive both the intake and exhaust valves. The DOHC engine is considered to be a very sophisticated and more efficient engine; but is sometimes more difficult to adjust the valves. Also called twin overhead camshaft.
Colloquial term for a truck tractor pulling two semi-trailers where the second trailer sits on a fifth wheel that is permanently attached and extends off the rear of the lead trailer. Most commonly used on flatbeds or tank trailers. The B-train is considered a more stable double trailers configuration. B-dollies.
A flexible coupling made of rubber and shaped like a ring doughnut. It is used, for example, between the front of the propeller shaft and the gearbox. Also called doughnut coupling.
A pin projecting from one of two mating surfaces which fits into a corresponding hole in the other thus lining up the two pieces accurately during assembly. Also called Locating dowel
An innovation technique. Metal dowel bars inserted across adjacent concrete slabs joints in the pavement. The dowel bars distribute the weight of traffic across each joint evenly and keep the joints from moving up and down, which reduces damage to the roadway.
A small cylinder (steel or wood) which is passed through or partly through two parts to provide proper Alignment and to prevent movement between them. Sometimes called locating pin.
Accurately dimensioned pin pressed into one assembly part and slipped into another assembly part to insure accurate alignment.
A fastener where both ends have gimlet points and is threaded similar to a lag bolt. The center section has a plain unthreaded shoulder. Used in joining two wooden members such as a leg to a table top.
A traditional type of vertical radiator, with header tank and bottom tank and a system of small tubes and cooling fins in-between, the hot water entering at the top and exiting at the bottom. This type of radiator has been replaced by a crossflow radiator.
A vertical force directed downward, produced by airflow around an object such as the body of a vehicle.
Downtime occurs when a vehicle is being repaired (esp. a commercial vehicle), it cannot fulfil its function. There is a loss in both potential proceeds from its use as well as the salary of its operators.
The condition of a clutch when it fails to fully disengage. The plates still rub against each other and causes intermittent contact between the engine output and the transmission gears. Called clutch drag.
The condition of brakes when the pads or shoes still rub the disc or drum. Called brake drag.
The amount the stern end of the keel is below the bow end when the ship is afloat, but not on an even keel.
(Cd) A number used in calculating the aerodynamic drag acting on a vehicle. The drag coefficient is a function of factors like the shape of the vehicle, airflow through the vehicle for ventilation and cooling. The number is determined in a wind-tunnel or by coasting tests performed on the vehicle. The lower the drag coefficient the less drag on the vehicle and the more aerodynamic is the vehicle. A sleek vehicle has a drag coefficient, or Cd, of about 0.30; a square, flat plate’s is 1.98. Also signified by Cx. If D is the drag of a body in a uniform stream of density p and velocity V, the drag coefficient is Cd=2D/pV²S where S is a representative area of the body, usually taken as frontal area. A teardrop has a Cd of 0.05, a barn door about 1.15, a Toyota Previa minivan is 0.33, a Porsche about 0.30, the GM Impact 0.19, the GM Sunraycer 0.12.
Trucker slang for a truck with no power as in ‘Drag ‘er up one side of the hill, let ‘er fly down the other.’
Trucker slang for Tow truck as in ‘Looks like that bulldog is gonna need a dragon wagon.’
Metal plates that have a car club’s name and logo identifying the vehicle and its driver as a member of that club.
A competitive match between two vehicles in which they race over a 1/4 mile course.
A specially constructed lightweight drag racing vehicle for drag racing, typically with a huge supercharged V-8 engine mounted well back in the chassis and extremely wide rear tires. Typical races are an acceleration contest from a standing start between two vehicles side by side over a measured distance. The accepted standard for that distance is either a quarter-mile (1,320 feet / 402.3 m) or an eighth-mile (660 feet / 201 m). A drag racing event is a series of such two-vehicle, tournament-style eliminations. During drag racing events, vehicles are classified by various criteria that take into account the extent of modifications to the car. These criteria include engine capacity, configuration of cylinders, frame type, vehicle construction materials, wheelbase, horsepower to weight ratio, number of cylinders, whether or not power adding devices such as turbochargers, superchargers or nitrous oxide are employed, vehicle type (such as car, truck, etc,), or even make and model for limited entry fields. The aforementioned divisions are in place to ensure that the cars are evenly matched during the race.
A tool for removing and tightening drain plugs, e.g., on transmissions and engine sumps, either as a multi-purpose tool with a number of different drives in the form of hexagonal or square projections at either end for different drain plugs, or as a special tool for one specific size of drain plug. Also called a drain plug wrench.
Drain plug spanner
A British term for a drain plug wrench
Drain plug wrench
A tool for removing and tightening drain plugs, e.g., on transmissions and engine sumps, either as a multi-purpose tool with a number of different drives in the form of hexagonal or square projections at either end for different drain plugs, or as a special tool for one specific size of drain plug. Also called a drain plug key.
A device which controls the flow of fluid (oil or coolant) out of the bottom of the cylinder block or the bottom of the radiator.
A turbocharger system in which the turbocharger sucks the air/fuel mixture through the carburetor or fuel in, i.e., the air and fuel mixing occurs upstream from the turbocharger
A vehicle used to haul goods. A container or piggyback is moved from a rail yard to another location (which is most likely a Distribution Center) and then returning that piggyback or container back to the initial pick-up point, is known as a dray. It is important that these containers get unloaded quickly and returned back to the original point so not to incur detention charges.
The work or cost of hauling goods, i.e., transporting freight by truck, primarily in local cartage.
Abbreviation for demonstrated reserve base
Abbreviation for Diagnostic Readout Box (Chrysler)
Abbreviation for Distributor Retard Control Valve
A one-of-a-kind futuristic, experimental automobile usually appearing at auto shows to stimulate interest in the manufacturer’s products. Much design benefit spurs from dream cars and many reach the production stage.
To give (a rough surface, flanges, etc.) the right shape by grinding or a similar process.
To prepare ore for smelting by removing impurities.
A short bar or punch used with a hammer to drive a component in or out of place for removal or installation.
The action where the rear end of a car swings to the right or left. In racing, a controlled drift will help you to go around the corner. In the winter, an uncontrolled drift might cause the car to face the wrong way or put you in the ditch.
Pan-shaped panel or trough used to collect condensate from evaporator.
(DP) An electric motor housing with ventilation openings in the end shells and the shells placed so drops of liquid falling within an angle of 15° from vertical will not affect performance. Usually used indoors, in fairly clean, dry locations.
The condition of a vehicle which may have many mechanical and appearance problems, but it has an engine which runs and wheels that turn, etc. so that it can be operated and driven.
The general qualitative evaluation of a powertrain’s operating qualities, including idle smoothness, cold and hot starting, throttle response, power delivery, and tolerance for altitude changes.
Any axle that carries power from the engine to the wheels that propel a vehicle. Also called power axle.
A flat belt which connects two or more pulleys so as to transmit motion from one pulley to the other.
The belt that transfers the rotation of the engine by way of the crankshaft pulley to drive the various devices such as the alternator for electricity, water pump for the cooling system, air conditioning compressor for air conditioning, or power steering pump for ease of steering.
An endless chain which encircles two or more sprockets so as to transmit motion from one sprocket to the other
Any journey of a vehicle in which the engine temperature is raised from cold (below 49°C) to normal operating temperature (above 71°C)
The end of an alternator, generator, etc., where the drive pulley or gear is located.
Drive end bracket
The cover which houses the drive end of an alternator or generator
A condition of fit (contact) between two parts that requires pressure to force the parts together. Usually the shaft is slightly larger than the hole so that they must be pounded or forced or driven together. Also called Force fit, Press fit, or Interference fit.
The gear which transmits the power to a driven gear.
A tool, typically in the form of a bar, for turning sockets to loosen and tighten nuts and bolts, with a male square drive to be inserted into the female square drive of sockets for the turning operation. They include ratchets, jointed handles, speed brace, T-handles, torque wrenches, speeder handle, and breaker bar.
All the individual components beyond the engine up to the wheels (e.g., clutch, drive shaft, differential, driven axles); but not the engine or transmission. Also called drivetrain or powertrain
All the components which together transmit power from the transmission to the drive axle(s). These consist of at least one driveshaft (propeller shaft) with a universal joint at each end.
Interchangeable unit providing motive power, either in the form of an electric motor and ancillaries, or an internal combustion engine with all necessary components, for alternative use in the same vehicle according to needs and conditions
Electric motor providing motive power in an electric vehicle
Something made to rotate by the engine or some other source of motive power.
The axle to which power is transmitted to drive the vehicle
An engine needs to transmit power to the wheels by the use of sprockets and chain (as in a motorcycle) or by a drive gear which meshes with a driven gear to propel the vehicle.
The central clutch plate carrying clutch linings and held under pressure between the flywheel and the pressure plate when the clutch pedal is released, and transmitting power to the gearbox input shaft via splines
A pulley which is surrounded by a belt to receive power from the drive pulley
On a vehicle which uses a chain (like a bicycle and some motorcycles), there are two important sprockets the drive sprocket is connected to the power source (the engine or your pedals) and the driven sprocket is usually connected to your rear wheel.
The wheel (or wheels) to which power is transmitted to drive the vehicle
The shaft that takes power from the clutch into the Gearbox.
A light plate bolted to the crankshaft to which the torque converter is attached in a vehicle with automatic transmission.
A clutch plate which is indexed into clutch basket (outer hub) by tabs. Drive plate has friction material bonded to its surface. When the clutch is engaged, the drive plate transfers power to the driven plate.
A pulley which is surrounded by a belt to transmit power to the driven pulley
The pulley attached to the nose of the engine crankshaft. It drives the compressor clutch pulley, usually with a V-type drivebelt
A collectible vehicle which is too good to treat as a beater and not quite good enough to show. It is a presentable old car or truck that is used for everyday purposes. It is maintained as though it were a late-model vehicle. With care, it could be easily restored to show car condition.
A person who operates the controls of a vehicle to regulate its speed and direction.
A switched electronic device housed in a computer that controls output state. For example, a driver controls how long a fuel injector remains open.
A tool used to insert something like a fastening device (e.g., screwdriver).
Original type of air bag, designed to protect the driver from being hurled into the steering wheel and instrument panel
Driver and Vehicle Licensing Agency
(DVLA) A section of the British Department of Transport which is responsible for keeping records of all registered vehicles and issuing registrations and licenses for vehicles as well as licenses for drivers. The center is located in Swansea.
A shipment for which the driver must collect freight charges at the time of delivery.
A mistake made by the operator of a vehicle particularly when there is an accident. An accident may be caused by a vehicle failure (e.g., a tire blowout), unsafe road conditions (e.g., snow, ice, fallen rock or tree), the inattention of a pedestrian, or the fault of a driver (e.g., drunkenness, inattention, intentional damage, disobedience to rules of the road).
A test of a driver’s ability to handle a vehicle. May be used to grant a driver’s license for a particular type of vehicle (i.e., motorcycle, passenger car, truck, bus, taxi)
A head, on a bolt or screw, designed for driving the fastener by means of a tool other than a wrench, such as a screwdriver.
Driver reaction distance
The distance traveled between the point at which the driver perceives a demand for braking and the start of brake application.
Driver reaction time
The time elapsed between the instant the driver perceives a demand for braking and the start of brake application
A metal strap or straps, surrounding the driveshaft to prevent the shaft from falling to the ground in the event of a Universal joint or shaft failure.
On a vehicle which uses a chain (like a bicycle and some motorcycles), there are two important sprockets the drive sprocket is connected to the power source (the engine or your pedals) and the driven sprocket is usually connected to your rear wheel.
Storage racking equipment with side rails to enable warehouse operators to stack product high in deep rows. Unlike Drive-in Rack, Drive-Through Rack allows access from either end of the row, as opposed to only being accessible from the aisle.
Any accessory for use with a socket wrench, including the drive handle
The axle which is driven by the engine through the drivetrain. Used to hold, align, and drive rear wheels and support weight of vehicle on rear wheel drive cars, or half shafts on front wheel drive cars that provide torque force to front wheels. Also called the drive axle or driven axle
The situation created by the amount of traffic, the weather, and state of the roads
The gear which is driven by the engine. Also called the driven gear
The personal behavior of the driver when controlling the vehicle, including the speeds he travels, how and when he shifts gears, how he uses the brakes, when and if he uses his signal lights, how he changes lanes, how he turns corners, etc.
A British term for driver’s license or operator’s license. A document which allows the holder to drive a certain type or types of vehicle, and is the only document required to be carried by the driver in Britain
An auxiliary light used at night to illuminate the side of the road and increase the viewing distance.
The wheel(s) which is driven by the engine through the drivetrain. Also called the driven wheel
Abbreviation for Daytime Running Lights, a system that automatically turns on the vehicle’s low beam headlights (or in some cases, a low-power high beam headlight or even bright park lights) when the parking brake is released and the ignition is on.
A condition of a turning flywheel which can be controlled from no load to full load. Also called steady state speed regulation.
On a bicycle, the vertical distance from the horizontal line connecting the two wheel axles and the bottom bracket, one way of determining the location of the bottom bracket in relation to the rest of the Bicycle frame
The action of leaving behind. For example in a race, you drop the vehicle you pass (i.e., overtake) and he gets further behind you as you continue to speed away.
A location where your supplies have been cached. In randonneuring events of 1200 km, you can pre-arrange to have a bag of extra clothes and other supplies waiting for you at a prescribed control (i.e., checkpoint). Also called a bag drop.
A one-piece rim with a deep center section which is lower than the two outer edges, this allows the bead of the tire to be pushed into the low area on one side while the other side is pulled over and off the Flange. The British term is ‘well-base rim’
Drop center rim taper
A passenger rim where both bead seats are tapered 5° or a tubeless truck rim where both bead seats are tapered 15°.
A type of brake using a shallow drum-shaped metal cylinder that attaches to the inner surface of the wheel and rotates with it. When you press down on the brake pedal, curved brake shoes with friction linings press against the inner circumference of the drum to slow or stop the vehicle.
Electrical device used to provide DC electricity, having no liquid in the cells.
Dry charged battery
A battery with the plates charged but lacking electrolyte; when ready to be placed in service, the electrolyte is added.
A clutch where the plate or plates do not run in a oil bath as opposed to a ‘wet clutch’ which does.
An enclosed basin used to place a ship on dry land so that all the submerged parts and fittings can be repaired.
A watertight vessel fitted with pumps and valves usually built in a U-shape. The valves are opened, the vessel sinks, the vessel to be docked is pulled over the drydock deck, the valves are closed and the pumps are started, as the drydock becomes more buoyant, drydocking the vessel to be repaired.
Dry friction exists when the rubbing parts have no other substance between them and are clean of other materials (i.e., no grease or oil). Opposite to Wet friction.
A hot-dip galvanizing method in which the metal components are first immersed in a solution of flux and then dried, so that they become pre-coated with a thin film of flux, which melts in the zinc bath, to which certain metals, such as tin and aluminum, may be added to give fluidity, and in the case of tin, brightness. The opposite is Wet galvanizing
An intake manifold with no integral coolant passages cast into it
Dry natural gas
Natural gas which remains after:
the liquefiable hydrocarbon portion has been removed from the gas stream (i.e., gas after lease, field, and/or plant separation)
any volumes of nonhydrocarbon gases have been removed where they occur in sufficient quantity to render the gas unmarketable.
Dry natural gas is also known as consumer-grade natural gas. The parameters for measurement are cubic feet at 15.5°C and 14.73 pounds per square inch absolute.
The adjustment of the float with a graduated rule or drill bit while the carburetor is disassembled on the bench. Usually consists of setting a prescribed clearance between the top of the float and the air horn
A cylinder sleeve application in which the sleeve is supported in the block metal over its entire length, the coolant does not touch the sleeve itself.
A paint fault where the paint pigment is not being held properly by the binder, or where the binder evaporates before the paint reaches the surface. Atomized paint that does not dissolve into the material being sprayed. It is caused by holding the gun too far from the work, too much air pressure or a Solvent that evaporates too fast.
A lubrication system in which the engine’s supply of oil is not contained in the crankcase (sump) but is pumped to the engine from an external container. This system allows the crankcase to be reduced in size and the engine to be installed lower in the chassis, and eliminates the oil starvation most conventional oiling systems suffer when subjected to the accelerative, braking, and cornering forces generated by a racing car.
Dry sump lubrication
Oil is gravity fed to the supply side of the oil pump from a remote oil tank. After the oil has been pumped through the four-stroke engine, it is returned to the oil tank by the return side of the oil pump.
A brake system that uses a tandem or dual master cylinder to provide separate brake system for both front and rear of vehicle. In the event of a loss of hydraulic fluid, one system may still work because it is independent of the other system. Often the front left brake is linked with the right rear brake. Likewise the right front brake is linked with the left rear brake. Some cars like the Rolls-Royce, link the two front brakes with the right rear brake, and the two front brakes with the left rear brake. Also called dual-circuit braking system.
Dual brake system
A brake system that uses two hydraulic circuits. Should one circuit fail, the other remains operational
An independent front suspension and steering arrangement used in the 1930s and ’40s, in which the axle beam is rigidly attached to the vehicle frame, and the kingpins carry sprung steering and suspension arms, from which the wheels are mounted on stub axles
A motorcycle manufacturer
A tube or channel through which air, gas, or liquid is conducted, conveyed, or moved.
A large metal container for garbage. The term is sometimes used to describe refuse trucks. Dumpsters are different from a roll-off containers. A dumpster is usually kept at a garbage collection point and not carried on a refuse truck. Some refuse trucks carry dumpsters short distances for loading, unloading, or distribution.
A trailer unit that is able to unload its cargo in one of three ways: back dump (the front of the trailer is raised and the cargo slides out the back); side dump (the cargo bucket tilts to one side allowing the cargo to slide off); bottom dump (panels open under the cargo bucket to let the cargo fall beneath).
A large truck with a bed designed to be tilted at its front to unload its contents usually through a gate in the rear.
In Britain it is a small truck with a tipping container in front of the driver, used in construction, like a front-end loader
A valve for relieving pressure, such as that between the turbocharger and the carburetor in some systems
Cushioning material (e.g., cardboard, pallets, plywood, foam rubber, air bags) placed among cargo to prevent their motion or damage while in transit.
A drum brake that has servo action in both the forward and reverse directions.
A servo brake with one double-end wheel cylinder and two linked self-energizing brake shoes
Duo-servo drum brake
A type of self-energizing drum brake that has servo action in both forward and reverse
Double, having two parts. Applies to motorcycle frames with two downtubes, and chains with double rows of rollers
A chain with two rows of rollers, used especially for timing chains.
(DC) The relationship between the operating and rest time. An electrical motor which can continue to operate within the temperature limits of its insulation system after it has reached normal operating (equilibrium) temperature is considered to have a continuous duty (CONT) rating. One which never reaches equilibrium temperature but is permitted to cool down between operations is operating under intermittent duty (INT) conditions
Many solenoid-operated metering devices cycle on and off. The duty cycle is a measurement of the amount of time a device is energized, or turned on, expressed as a percentage of the complete on-off cycle of that device, in other words, the duty cycle is the ratio of the pulse width to the complete cycle width
The percentage of time that a circuit is energized during one complete on/off cycle during pulse-width modulating.
In a contact breaker ignition system, the number of degrees the breaker cam rotates from the time the breaker points close until they open again. Also called the dwell angle or dwell period.
In a breakerless ignition system, the time during which the electronic control unit allows current to flow through the primary winding of the coil, which in ignition systems with a Hall generator is determined by the width of the vanes.
The length of time in crankshaft degrees the ignition contact points are closed.
Abbreviation for Distillers Wet Grains — An animal feed coproduct prior to drying. Typically contains process syrup or at least a portion of the process syrup. DWG is sometimes sold as a final product.
A special blue dye used to check a valve job. When applied to the valve set to show up as a dark ring contrasted against the brightly finished top and bottom cuts, making the seat easier to see and measure
A piston ring with an L-shaped cross section designed to use combustion pressure to improve sealing.
When the center line of the weight mass of a revolving object is in the same plane as the center line of the object, that object would be in dynamic balance. For example, the weight mass of the tire must be in the same plane as the center line of the wheel. static balance is made off the vehicle and determined with the tire stationary. Dynamic balance is made with the tire in rotation.
Dynamic ignition timing
Before the introduction of a strobe light, ignition timing was done statically in that the distributor was moved a certain measured amount. With modern engines, a timing light or strobe light is used. It is connected, generally, with the spark plug of the number one cylinder. As power is provided to that cylinder from the coil, the timing light flashes. When the light is projected to the flywheel, the timing marks are illuminated. Moving the distributor will make the timing mark move closer to a fixed mark (retarded) or further away (advanced). Also called Stroboscopic ignition timing. The opposite is Static ignition timing
Lack of balance in a rotating part such as a wheel, which can cause vibration and shudder
Oil seal between a moving and a stationary part. Opposite to Static seal
The pressurizing of the air/fuel mixture using the natural dynamic behavior of the aspirated air, and not some mechanical device to compress it
Dynamic timing meter
A GM diesel tool used for measuring timing while the engine is running by using a quartz sensor in the combustion chamber that measures the point of combustion and converts this to timing in degrees of crankshaft flotation through the use of a magnetic crankshaft pickup and microprocessor
Dynamic tire balance
The action of making sure that the tire and wheel is in perfect balance can be done in two ways. Both ways involve removing the wheel from the vehicle. In the static method, the tire and wheel are stationary and is placed on a spindle to check for imbalance by using a bubble level, then correcting the problem by placing weights to counteract the imbalance. The dynamic method involves spinning the wheel on a balancing machine which will detect the point of imbalance and recommend the proper weight and location to correct the imbalance.
A noise-producing condition in an electric motor caused by the nonsymmetrical weight distribution of a rotating member. The lack of a uniform wire spacing in a wound armature or casting voids in a rotor or fan assembly can cause relatively high degrees of unbalance
A British term for a Generator producing direct current.