- Dr
- Abbreviation for Door.
- Draft
-
- An unpleasant current of air intruding into the interior of a car.
- The depth of the ship below the waterline measured vertically to the lowest part of the hull.
- To follow behind a faster vehicle to take advantage of its air currents.
Also see
- Draft indicator
- Instrument used to indicate or measure chimney draft or combustion gas movement. Draft is measured in units of .1 in. of water column.
- Drafting
- The action of following closely behind a faster vehicle so as to take advantage of
the aerodynamic effect which causes both the vehicles behind and the one in front to
move faster.
Also see
- Draft marks
- The numbers which are placed on each side of a ship at the bow and stern from the lower edge of the number to the bottom of the keel
- Draft regulator
- Device which maintains a desired draft in a combustion-heated appliance by automatically controlling the chimney draft to the desired value.
- Drag
-
- To accelerate a vehicle from a standing start, over a course one-fourth mile in length. Also called drag racing.
- Used by some Drivers when referring to challenging another Driver to an Acceleration race.
- Air resistance.
- 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.
- Drag coefficient
- (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.
- Drag link
- A steel rod connecting the Pitman arm to one of the Steering knuckles. On some installations the drag link connects the pitman arm to a center Idler arm.
- Dragon fly
- Trucker slang for a truck with no power as in "Drag 'er up one side of the hill, let 'er fly down the other."
- Dragon wagon
- Trucker slang for Tow truck as in "Looks like that bulldog is gonna need a dragon wagon."
- Dragster
- A specially constructed car for drag racing, typically with a huge supercharged V-8 engine mounted well back in the chassis and extremely wide rear tires
- Drag wheel
- Special Steering wheel used on some Dragsters. Often consists of a crossbar Spoke and a portion of rim on each end.
- Drain
-
- To empty a container usually from the bottom.
- A tube or channel which allows water to run to another place.
- Drain hole
- A hole drilled in the bottom of a box section or a door, to allow water that has accumulated to escape so as to prevent or delay rusting
- Drain plug
- Usually a threaded plug at the lowest point of the sump, gearbox, cooling system, etc., which is removed in order to drain the oil or coolant, and typically has a recessed hexagon head.
- Drain plug key
- 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 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.
- Drain tap
- 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.
- Draught
- British spelling for Draft
Also see
- Draw
-
- To form wires by pulling the wire stock through a series of hardened dies.
- The process of removing the hardness from a piece of metal.
- The amount of electrical load or electrical requirement.
- Drawbar
-
- Two converging bars forming a V-frame or an A-frame at the front of a trailer or motorhome, which carry the coupling for attaching to the towing vehicle
- A metal bar that connects a truck and trailer. Sometimes referred to as the tongue of the trailer.
- Drawing
- The process of pulling material like a wire through a die to reduce its diameter
to the size required.
Also see
- Draw-through
- 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
- Dream car
- 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.
- Dress
-
- To give (a rough surface, flanges, etc.) the right shape by grinding or a similar process.
- To prepare ore for smelting by removing impurities.
- Dribble
- Insufficiently atomized fuel issuing from the fuel injection nozzle at or immediately following the end of the main injection phase
- Drier
-
- A dehumidifier.
- A drying oven.
- Substance or device used to remove moisture from a refrigeration system.
- A device located in the liquid line, contains desiccant to absorb moisture from the system. Usually combined with the receiver
- Drift
-
- 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.
- To deviate from the normal direction.
Also see
- Drift punch
- A tapered tool which is hit with a hammer and used to remove or install pins, shafts, rivets, etc. or to align holes when inserting screws and bolts.
- Drill
-
- A pointed cutting tool which is rotated under pressure to bore a round hole.
- The action of using a drill (usually a twist drill) to make a round hole.
- Drill bit
- A piece of rod with spiral recesses cut in it and a hardened steel tip, made in different sizes for drilling different sized holes, and inserted in the chuck of a drill
- Drilled
- An expression used to describe a hole which has been cut into a crankshaft to allow oil to be fed to the main bearings on the connecting rod throws.
- D-ring
- A D-shaped ring found on many models of Bicycle shift levers, used to adjust the level of tension on the inner parts of the lever.
- Drip molding
- The curved metal molding around the edge of the roof that directs water away from the side
windows. Also called Drip rail
Also see
- Drip moulding
- British term for Drip rail
- Drip-proof enclosure
- (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.
Also see
- Drip rail
- A gutter running along either side of the roof to take water to the front or rear of the car, and prevent it from dripping into the car when the door is opened. The British term is drip moulding
- Drive
-
- To travel in a car as in the expression, "She drives to work."
- To operate a vehicle as in the expression, "Martha can drive her Dad's car."
- To cause a wheel, shaft, etc. to turn or rotate.
- To propel a vehicle.
- A journey in a car as in "The drive to Chicago was uneventful."
- To go for a drive as in, "We went for a drive last Sunday."
- A stretch of private road leading to a house (i.e., driveway).
- A means of transmitting power or motion as in "The drive is controlled by a servo switch."
- A tool which has a square end (1/4 inch, 3/8 inch, or 1/2 inch) which fits into a recess in a corresponding socket for the installation or removal of nuts and bolts.
- A die position.
- One of the forward gears marked on the gear selector of an automatic transmission.
Also see- Adjustable Speed Drives
- All-wheel drive
- Automatic four-wheel drive
- Axle drive
- Belt drive
- Bendix type starter drive
- Bevel gear drive
- Camshaft drive
- Camshaft drive sprocket
- Center drive
- Chain drive
- Cush Drive
- Direct drive powertrain
- Direct drive
- Dual drive
- Eccentric drive
- External Drive
- Ferguson four-wheel drive
- Final drive gear
- Final drive ratio
- Final drive
- Fixed drive
- Flexible drive
- Flexible drive handle
- Four-wheel drive
- Friction drive
- Front-wheel drive
- Full-time four-wheel drive
- Hotchkiss drive
- Inertia drive
- Intermediate drive plate
- Left-hand drive
- Machine Drive
- Meshing drive
- Metallic drive screw
- Overrunning clutch starter drive
- Part-time four-wheel drive
- Permanent four-wheel drive
- Primary Drive
- Real-time four-wheel drive
- Rear-wheel drive
- Rear-wheel drive transaxle
- Right-hand drive
- Shaft drive
- Strap drive
- Tandem drive
- Test-drive
- Test drive
- Torque tube drive
- Torsen four-wheel drive
- Tri-drive
- Two-wheel drive
- V-belt drive
- Driveable
- 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.
- Driveability
- 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.
- Drive belt
-
- 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.
Also see
- Drive chain
- An endless chain which encircles two or more sprockets so as to transmit motion from one sprocket to the other
- Drive Cycle
- Any journey of a vehicle in which the engine temperature is raised from cold (below 49°C) to normal operating temperature (above 71°C)
- Drive fit
- 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.
- Drive handle
- 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.
Also see
- Drive layout
- The arrangement of the order of the engine, transmission, and driven axles, e.g., Front-wheel drive, rear-wheel drive, mid-engine drive, four-wheel drive, two-wheel drive
- Drive line
- See
- Driveline
-
- 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.
- Drive module
- 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
- Driven gear
- 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.
- Driven plate
- 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
- Driven sprocket
- 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.
- Drive pinion
-
The shaft that takes power from the clutch into the Gearbox.
Drive pinion
Also see
- Drive plate
- A light plate bolted to the crankshaft to which the torque converter is attached in a vehicle with automatic transmission.
- Drive pulley
-
- 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
- Driver
-
- 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 tool used to insert something like a fastening device (e.g., Screwdriver).
- Driver air bag
- 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.
- Driver and Vehicle Licensing Center
- The location for the British Driver and Vehicle Licensing Agency located in Swansea.
- Driver error
- 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).
- Driver evaluation
- 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)
- Driver Head
- 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
- Drive Screw
- A piloted, multiple threaded screw with a large helix angle, used for permanent applications. It forms a mating thread as it is hammered or pressed into a prepared hole.
Also see
- Driveshaft
-
The shaft connecting the Transmission Output shaft to the DifferentialPinion shaft. It transmits power from the transmission to the Differential. It is found primarily on rear-drive vehicles. There is usually a Universal joint on either end. Also called propeller shaft.
Click image to supersize
DriveshaftAlso see
- Drive shaft
- See
- Driveshaft safety strap
- 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.
- Drive sprocket
- 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.
Also see
- Drive train
-
- The entire moving part of the car or motorcycle: Engine, Clutch, Transmission, Driveshaft, Differential, axles, and sometimes the wheels.
- The moving parts of a bicycle: Derailleurs, Chain, Freewheel, and Crankset.
Also see
- Drivetrain
-
- The entire moving part of the car or motorcycle: Engine, Clutch, Transmission, Driveshaft, Differential, axles, and sometimes the wheels.
- The moving parts of a bicycle: Derailleurs, Chain, Freewheel, and Crankset.
Also see
- Driveway
-
- A short drive, often leading to a garage
- A privately maintained access to residential, commercial, or industrial properties.
- Drive wheels
- The set of wheels that actually propel the car forward and backward. Vehicles are now identified as having Front-wheel drive, Rear-wheel drive, Four-wheel drive, or All-wheel drive.
- Driving
-
- Providing motive power, making a gear, shaft, etc. rotate.
- Controlling the movement and direction of a vehicle.
- Driving axle
- 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
- Driving conditions
- The situation created by the amount of traffic, the weather, and state of the roads
- Driving habits
- 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.
- Driving license
- 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
- Driving light
- An auxiliary light used at night to illuminate the side of the road and increase the viewing
distance.
Also see
- Driving mirror
- A British term for either the interior rear-view mirror or the mirrors mounted on the outside of the front doors or the front fenders
- Driving position
- The position in which the driver grasps the steering wheel and adjusts the location of the seat in relation to the pedals.
- Driving wheel
- The wheel(s) which is driven by the engine through the drivetrain. Also called the driven wheel
- DRL
- Acronym for Daytime Running Lights -- A system that automatically turns on a 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.
- Drop
-
- A sudden reduction of pressure or voltage, etc.
Also see
- 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
Also see
- 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.
Also see - A sudden reduction of pressure or voltage, etc.
- Drop arm
- A British term for the Pitman arm
- Drop Center
- The main part or center of the frame is dropped down between the front and rear wheels to lower the vehicle to create a lower center of gravity.
- Drop-center axle
- A beam axle in which the main central portion of the beam is lower than the wheel centers, which was the usual layout for front axles until independent front suspension became almost universal
- Drop center rim
- 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°.
- Drop forged
- A part that has been formed by heating the steel blank red hot and pounding it into shape with a powerful drop hammer.
- Drop forging
-
- A piece of steel shaped between dies while hot
- Forming metal, usually under impact, by compression within dies designed to produce the required shape.
- Drophead
-
- A British term for a Convertible. The word "head" refers to the roof.
- Having a folding top which can be raised or lowered over the passenger compartment.
- Drophead coupe
- (DHC) This is a two-door automobile which has the appearance of a Convertible, but the roof is fixed in place. In Europe, it is called a Cabriolet.
- Drophead coupé
- (DHC) This is a two-door automobile which has the appearance of a Convertible, but the roof is fixed in place. In Europe, it is called a Cabriolet.
- Dropout hanger
- A threaded metal piece that extends below the right rear Dropout of a Bicycle used as a mount for the rear Derailleur.
- Dropped axle
- A front axle that has been altered so as to lower the Frame of the vehicle, consists of bending the axle downward at the outer ends.
- Dropped valve
- A situation where the rising piston hits a valve which has become dislodged or open at the wrong time.
- Drops
- The lower, straight portion of a turned-down-type Handlebar set.
- Drum
-
- The part of a drum brake that rotates with the axle hub. The brake shoes press against the inside of the drum when the brakes are applied
- A cylindrical container.
- A Housing for Transmission gears where the Bands are located.
- To make a whump, whump sound.
- Drum brake
-
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.
Click image to supersize
Drum BrakeAlso see
- Dry
-
- For paint, to lose its wetness often to the place where the surface is not even tacky.
- For bearings, to lack grease or other lubricant.
- Dry ballast
- A form of Ballasting where a fine powder of barium sulfate is inserted inside the tire. It is sometimes referred to incorrectly as Lead ballast because of one brand name, Ledballast.
- Dry boiling point
- The temperature at which fresh Brake fluid from a
new container will boil.
Also see
- Dry bulk tanker
- Sometimes called air-can trailers. Used exclusively for hauling dry bulk material. Cargo is emptied pneumatically.
- Dry capacitor condenser
- Electrical device made of dry metal and dry insulation; used to store electrons.
- Dry cell
- A Battery (like a flashlight battery) that uses no liquid Electrolyte.
- Dry charged battery
- A Battery with the plates charged but lacking Electrolyte; when ready to be placed in service, the Electrolyte is added.
- Dry clutch
- A clutch where the plate or plates do not run in a oil bath as opposed to a "wet clutch" which does.
- Dry dock
- An enclosed basin used to place a ship on dry land so that all the submerged parts and fittings can be repaired.
- Dry friction
- 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.
- Dry galvanizing
- 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
- Dry hole
- An exploratory or development well found to be incapable of producing either oil or gas in sufficient quantities to justify completion as an oil or gas well.
Also see
- Dry ice
- Refrigerating substance made of solid carbon dioxide which changes directly from a solid to a gas (sublimates). Its subliming temperature is -79°C.
- Drying oven
- An enclosure where painted vehicle bodies are subjected to heat in order to dry and/or bake on the paint
- Drying time
- The time required for a solvent to evaporate after an adhesive film has been spread over the two surfaces to be bonded
- Dry liner
- When a Cylinder sleeve is pressed into a bore
and the cooling fluid does not contact the outside of the sleeve, the engine has a dry liner.
Also see
- 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 setting
- 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
- Dry sleeve
- 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.
Also see
- Dry-spray
- 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.
- Dry sump
- 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 system
- Refrigeration system which has the evaporator liquid refrigerant mainly in the atomized or droplet condition.