Dictionary of Automotive Terms Abbreviations

DICTIONARY OF AUTOMOTIVE TERMS - "Pr"

PR

Acronym for Ply rating
Acronym for Pressure Relief

Pratt and Whitney key: (P&W) A bar like a Flat key except the ends are oval shaped.

PRC: Acronym for Pressure Regulator Control solenoid

Prechamber: A small upper chamber in the cylinder head of a diesel engine, connected to the main combustion chamber by a narrow passage; fuel is injected into the prechamber (also called swirl chamber) where it is ignited before spreading to the main chamber.
Also see
Pre-combustion chamber.

Pre-chamber: See
Pre-combustion chamber.

Precipitation: See
Acid Rain

Precipitation hardened stainless steel: Type 630 stainless, little used, expensive and not sold as commercial products, it combines corrosion resistance of 300 series stainless with high tensile strength of 400 series.

Precipitation Hardening: Hardening caused by the precipitation of a constituent from a supersaturated solid solution.

Precision insert bearing: A very accurately made replaceable type of bearing, it consists of an upper and lower shell, the shells are made of steel to which a Friction type bearing material has been bonded, Connecting rod and Main bearings are generally of the precision insert type.

Precision Machine Screws: Slotted machine screws, milled from bar, cut thread, and are machined finished Class 3A fits.

Precombustion chamber: See
Pre-combustion chamber.

Pre-combustion chamber: A small chamber located outside the Combustion chamber of some cars in which a small amount of rich Fuel-air mixture can be ignited to increase Fuel efficiency and cut emissions. Found principally on Diesel engines and Stratified charge engines. Also called pre-chambers.

Pre-combustion engine: A diesel engine using Indirect injection. The British term is Indirect injection engine

Pre-compounding: A process of mixing plastic raw materials with additives

Pre-compress: To compress the fuel-oil mixture first

Pre-compression: See
Crankcase compression

Pre-compression chamber: A chamber below the pistons in a two-stroke engine in which the fuel-oil mixture is initially compressed in order to enable more fresh charge to be fed into the cylinder

Pre-converter vehicle: A car built prior to the enforcement of emission control standards requiring a catalytic converter to be fitted to every new car

Precooler condenser: Used to cool the refrigerant prior to entering main condenser.

Precured tread rubber: Pre-cured rubber, usually of high density and available in various tread designs, is lined with cushion gum before applying to a buffed Casing using the Cold cap method of retreading. Recently it has been applied in some Hot cap molds employing a smooth matrix or other modifications.

Precursors: See
Ozone Precursors

Pre-engaged Bendix starter: A combination of Bendix and pre-engaged starter drives

Pre-engaged starter: A starter motor in which the solenoid-operated pinion engages with a flywheel ring gear before the full electric current flows; an overrunning clutch enables the pinion to freewheel before disengaging, once the engine has fired

Preferential oxidation: A reaction that oxidizes one chemical rather than another. In fuel cells, the reaction is used to preferentially oxidize carbon monoxide to carbon dioxide from the Reformate stream after the water-gas shift reactor and before the fuel cell. Same as selective oxidation.

Preferential Tariff: See
Generalized Preferential Tariff

Pregnant roller skate: Trucker slang for a Volkswagen Beetle as in "Better get over, we got a pregnant roller skate trying to merge ahead."

Preheater system: A cold starting aid for diesel engines, consisting of glow plugs, a glow-control unit, and a glow plug and starter switch, for preheating the combustion chamber or the intake air up to auto-ignition temperature

Preheating

Temperature to which a metal is heated before an operation is performed on the metal (welding, cutting, forming, etc.).
The application of some heat prior to the later application of more heat, Cast iron is preheated to avoid Cracking when the welding process is started. A Coil (ignition) is preheated prior to testing.

Also see
Converter preheating.

Preheating zone: A section in Hot-wax flooding units, in which body shells are preheated to 60°C

Preignition: The fuel charge being ignited before the proper time. Sometimes causes Pinging or Detonation. This is the Combustion of the Fuel-air mixture that is not a result of the Spark plug's firing, but by high pressure, a flame, or a hot surface.

Preload: A bicycle suspension adjustment that usually involves modifying pressure or adjusting the elastomers to ensure that the suspension responds appropriately to the rider's weight

Preloading: Adjusting an antifriction bearing, Ball joint, or spring so that it is under mild pressure, this prevents bearing looseness under driving stress.

Prelubricator: A lubrication system consisting mainly of an electronically controlled pump that circulates pressurized engine oil to an engine's vital parts for about six seconds when the ignition is switched on prior to starting the engine; reduces friction during cold starts and prolongs engine life

Prelude: Click image for books on
Honda Prelude

A model of automobile manufactured by Honda

Premium: See
Insurance premium

Premium Compact SUV: An upscale sport utility vehicle of the Compact SUV size as represented by the following Acura RDX, BMW X3, Infiniti EX35, and Land Rover LR2.

Premium gasoline: Gasoline with a high amount of octane to give it an antiknock index (R+M/2) greater than 90. Includes both leaded premium gasoline as well as unleaded premium gasoline.
Also see
Leaded Premium Gasoline
Unleaded Premium Gasoline

Premium Large SUV

Upscale model of a Large SUV such as the following.

Premium Large SUV
Audi Q7	Cadillac Escalade	Hummer H2
Infiniti QX56	Land Rover Range Rover	Lexus LX 570
Lincoln Navigator	Mercedes-Benz GL550-Class	Toyota Land Cruiser

Premium Midsize SUV

An upscale Midsize SUV as seen in the following models

Premium Midsize SUV
Buick Enclave	Buick Rainier	Cadillac SRX	Chrysler Aspen
Ford Explorer (Eddie Bauer Edition)	Infiniti FX	Jeep Grand Cherokees,	Land Rover's LR3
Land Rover Range Rover Sport	Lexus GX 470	Lexus RX	Lexus RX300
Lincoln MKX	Mercedes-Benz R-Class	Porsche Cayenne	Saab 9-7X Aero
Volkswagen Touareg 2	Volvo XC90

Premixing burner: A power burner in which all or nearly all of the air for combustion is mixed with the gas as primary air.

Pre-owned vehicle: A Used vehicle. A term coined by car dealers to avoid the idea that a second-hand vehicle is used up (i.e., finished its usefulness).

Prepreg: The reinforcing or molding material already impregnated with a synthetic resin

Pre-pump: An electric fuel pump usually located in the fuel tank that keeps pressure in the fuel line prior to the main fuel pump to prevent vapor lock.

Prescribed burning: Skillful application of fire to natural fuels that allows confinement of the fire to a predetermined area and at the same time produces certain planned benefits.

Pre-selector gearbox: An arrangement that enables the driver to select a gear Speed before he needs it and then depress the clutch pedal when he desires to use the selected gear.

Preselector gearbox: See
Pre-selector gearbox.

Preset station button: A button for tuning a radio automatically to a preset frequency, i.e., one radio station can be allocated to each button

Press: See
Drill press

Press brake: A large type of sheet metal folder, built to handle larger panels and thicknesses

Press, drill: See
Drill press.

Pressed panel: A panel produced with special press tools and dies, as opposed to a hand-made panel

Pressed steel: Sheet steel made into curved sections by press forming. It is often used in the construction of the frame and forks

Press fit: An Interference fit. A fit so tight that an object must be removed with a Puller or a press.

Also See
Drive fit
Interference fit
Force fit

Pressing plant: A factory specializing in the manufacture of automobile bodies

Pressure

The force due to the weight of a substance exerted over the area the substance occupies. In metric measure, it is the force acting on each square meter. To calculate pressure, divide the force (in newtons) by the area (in square meters). It is measured in newtons per square metre (N/m²). In Imperial (U.S.) measure, it is measured in pounds per square inch (lb/in.²) (psi).
Energy impact on a unit area; force or thrust on a surface.
Force per unit area. As used in air conditioning systems, it refers to the refrigerant pressure, which is expressed in pounds per square inch (psi)

Also See
Absolute pressure
Air pressure
Allowable Working Pressure
Atmospheric pressure
Atomizing pressure
Back pressure
Barometric Pressure
Boiler Pressure
Boost pressure
Brake mean effective pressure
Cabin Differential Pressure
Center of pressure
Clutch pressure plate
Combustion pressure
Control pressure
Critical Pressure
Dead-head Pressure
Design Pressure
Differential Pressure
Discharge pressure
Exhaust back pressure
Extreme pressure lubricant
Fuel pressure
Gauge Pressure
Governor pressure
Head Pressure
High pressure
High pressure foaming
High pressure relief valve
Hydraulic Pressure
Hydraulic pressure pump
Indicated mean effective pressure
Injection Pressure
Injector Opening Pressure
Leak-off Pressure
Line pressure
Low Head Pressure
Low pressure indicator
Low pressure tire
Low-side Pressure
Low-suction Pressure
Lubricating pressure
Manifold absolute pressure sensor
Maximum Operating Pressure
Mean effective pressure
Mean indicated pressure
Medium Pressure
Modulator pressure
Negative back pressure modulated valve
Negative back pressure valve
Oil-combination splash and pressure system
Oil-full pressure system
Oil pressure
Oil pressure gauge
Oil pressure sensor
Oil pressure switch
Oil pressure warning light
Operating Pressure
Partial Pressures
Pressure bleeder
Pressure cap
Pressure relief valve
Primary Pressure
Ram pressure
Rated pressure
Reference Pressure
Reid Vapor Pressure
Residual pressure valve
Solution pressure
Static pressure
Suction Pressure
System Pressure
Tire pressure
Vacuum Pressure
Vapor Pressure
Zero Absolute Pressure

Pressure, absolute: See
Absolute pressure

Pressure accumulator: A spherical pressure tank of about 10 mm diameter in an hydraulic brake booster. A diaphragm separates the pressure accumulator into two chambers, one contains pressurized nitrogen, the other contains hydraulic fluid supplied by the hydraulic pump; pressure inside the accumulator is in the order of 60 bar

Pressure Actuator: See
Electro-hydraulic Actuator

Pressure, atmospheric: See
Atmospheric pressure

Pressure, back: See
Back pressure

Pressure bleeder

A device that forces Brake fluid under pressure, into the Master cylinder so that by opening the bleeder screws at the Wheel cylinders, all air will be removed from the Brake system.
A container with a brake fluid and air compartment separated by a diaphragm. Used with adapters to supply a constant, clean pressurized source of brake fluid for bleeding.

Pressure buildup: As a tire heats up as it travels on the road, the air inside the tire expands and thus increases the air pressure. Any increase exceeding 15% above starting cold pressure should be investigated. The practice of Bleeding the excess or hot pressure should be avoided.

Pressure burner: A burner which is supplied with a gas-air mixture under pressure, usually from 0.5 to 14.0 inches water column (1/8 to 3.5kPa) and occasionally higher.

Pressure cap: Pressure cap

A special cap for the Radiator, it holds a predetermined amount of pressure on the water in the Cooling system, this enables the water to run hotter without boiling. In this way, the engine can operate at a higher and a more efficient temperature without danger of overheating. The cap also has a Vacuum valve that lets air into the Cooling system if the pressure falls too low to prevent outside air pressure from causing a partial collapse of the radiator.

Pressure Check Valve: See
Residual Pressure Check Valve

Pressure Control: See
Head Pressure Control
Low-side Pressure Control

Pressure Controlled: See
Manifold Pressure Controlled

Pressure Control Valve: See
Suction Pressure Control Valve

Pressure Curve: See
Vapor Pressure Curve

Pressure Differential: See
Cell Pressure Differential

Pressure differential sensor: A sensor that reads pressure changes in the intake manifold in relation to barometric pressure. Also called a Manifold pressure sensor, Manifold vacuum sensor, or Vacuum sensor

Pressure differential switch: A hydraulic pressure-operated switch (often included in a combination valve) which activates the brake failure warning light when one of the brake circuits (in a dual-circuit system) falls due to a system leak and associated pressure drop

Pressure differential valve

Senses unbalanced hydraulic pressure between two halves of the split brake system
A spool-type valve used in dual brake systems to detect any difference in pressure between the systems. Its motion usually operates a switch that sends current to a warning lamp on the instrument panel.

Pressure differential warning switch: A component of the brake hydraulic system that warns the driver of a failure in one of the circuits

Pressure drop

The difference in pressure between two points in the system, usually caused by a restriction device. Specifically the difference in pressure where fuel metering occurs. In electronic injection system, this is the difference between fuel system pressure and intake manifold pressure. In Bosch CIS, it is the difference between system pressure inside the control plunger and the pressure outside the slits, in the upper-chamber of the differential-pressure valves
Pressure difference at two ends of a circuit, or part of a circuit; the two sides of a filter.

Pressure-feed spray gun: A type of spray gun with a separate paint container (pressure-feed tank). It is used mostly for spraying highly viscous materials such as spray putty

Pressure foaming: See
High pressure foaming
Solid Phase Pressure Forming

Pressure forming: See
Solid phase pressure forming

Pressure gage: See
Oil pressure gauge

Pressure gauge: Instrument for measuring the pressure exerted by the contents on its container. Reading in pounds per square inch (psi) above atmospheric pressure.

Also See
Oil pressure gauge
Tire pressure gauge

Pressure, head: Force caused by the weight of a column or body of fluids. Expressed in feet, inches, or psi.

Pressure-heat diagram: Graph of refrigerant pressure. heat and temperature properties. (Mollier's diagram).

Pressure indicator: See
Low pressure indicator

Pressure limiter: Device which remains closed until a certain pressure is reached, then opens and releases fluid to another part of system or breaks an electric circuit.
Also see
Low-side Pressure Limiter

Pressure limiting valve: A British term for a Proportioning valve

Pressure Line: See
High Pressure Line

Pressure Lubricant: See
Extreme Pressure Lubricant

Pressure lubrication

Forced-feed lubrication.
Lubrication system with crankcase scavenging. Fresh oil is supplied from a separate container and lubricates the engine components as it passes through the crankcase. The oil is ignited along with the air/fuel mixture. With this system, it is no longer necessary to add oil to the fuel when filling up

Pressure modulated: See
Negative back pressure modulated valve

Pressure modulated valve: See
Brake Pressure Modulator Valve
Negative back pressure modulated valve

Pressure Monitor System: See
Tire Pressure Monitor System

Pressure motor control

Device which opens and closes an electrical circuit as pressures change.
High- or low-pressure control connected into the electrical circuit and used to start and stop motor. It is activated by demand for refrigeration or for safety.

Pressure-operated altitude valve: (poa) Device which maintains a constant low-side pressure, independent of altitude of operation.

Pressure, operating: Pressure at which a system is operating.

Pressure Period: See
Peak Pressure Period

Pressure plate

The plate that carries the brake pad in a disc brake. Also called Backplate.
The part of the clutch assembly which is pressed against the clutch plate by the clutch springs to transmit the drive.

Also See
Clutch pressure plate

Pressure pump: See
Hydraulic pressure pump

Pressure radiator cap: See
Pressure cap.

Pressure regulating valve

Any valve which maintains pressure at or under a certain pressure; specifically the pressure relief valve of the oil pump.
In a continuous injection system, part of the fuel distributor, consisting basically of a spring-loaded steel diaphragm which serves to keep the pressure drop across the metering ports at a constant 0.1 bar

Pressure regulator

A spring-loaded diaphragm-type pressure-relief valve which governs the pressure of the fuel delivered to the fuel injectors by the fuel pump and returning the excess to the tank.
A device placed in a gas line for reducing, controlling and maintaining the pressure in that portion of the piping system downstream of the device.

Also See
Differential Pressure Regulator
Evaporator Pressure Regulator
Exhaust Pressure Regulator
Fuel Pressure Regulator
System Pressure Regulator

Pressure regulator, evaporator: Automatic pressure regulating valve mounted in suction line between evaporator outlet and compressor inlet. Purpose is to maintain a predetermined pressure and temperature in the evaporator.

Pressure regulator valve: A valve which releases hydraulic fluid if pressure exceeds a preset value
Also see
Evaporator Pressure Regulator Valve

Pressure relief: What you must do to all fuel injection system before cracking a line and opening up the system

Pressure relief valve

A one-way valve designed to open at a specific pressure to prevent pressures in the system from exceeding certain limits. In an engine's lubrication system, a pressure-relief valve opens to relieve excessive pressure that the oil pump might develop.
A valve which automatically opens and closes a relief vent, depending on whether the pressure is above or below a predetermined value.

Also See
Blowoff valve
High pressure relief valve
Safety valve
Waste gate

Pressure ridge: A work-hardened edge of a damaged panel area that will often remain, even after the area has been smoothed with hammer and dolly; it must then be dressed with hammer and body spoon

Pressure Safety Cutout: See
Head Pressure Safety Cutout
Low Pressure Safety Cutout
Oil Pressure Safety Cutout

Pressure sensing line: A tube that connects the remote bulb to the expansion valve. Also called Capillary tube

Pressure sensing switch: Device, used on some late model GM and Ford vehicle, which cycles compressor operation in accordance with pressure changes sensed at the accumulator

Pressure sensitive adhesive: Type of adhesive that retains its tack or stickiness even after complete release of the solvent

Pressure sensor: See
Barometric And Manifold Absolute Pressure Sensor
Barometric pressure sensor
Manifold absolute pressure sensor
Manifold Pressure Sensor
Oil pressure sensor
Steering Pressure Sensor

Pressure, suction: Pressure in low-pressure side of a refrigerating system.

Pressure switch: Switch operated by a rise or drop in pressure.; See
Oil pressure switch

Pressure system: See
Oil-combination splash and pressure system
Oil-full pressure system

Pressure tap: Also called a Fuel-injection system test port

Pressure tire: See
Low pressure tire

Pressure Transducer Valve: See
Exhaust Back Pressure Transducer Valve

Pressure Type Check Valve: See
Residual Brake Pressure Type Check Valve

Pressure-vacuum cap: Fuel tank filler cap designed to prevent loss of fuel or vapor from tank

Pressure valve: See
Differential Pressure Valve
Negative back pressure valve
Residual pressure valve

Pressure vessel: Containers for the containment of pressure either internal or external. This pressure may be obtained from an external source, or by the application of heat from a direct or indirect source, or by any combination of them.

Pressure Warning: See
Low Tire Pressure Warning

Pressure warning light: See
Oil pressure warning light

Pressure Warning Switch Assembly: See
Differential Pressure Warning Switch Assembly

Pressure water valve: Device used to control water flow. It is responsive to head pressure of refrigerating system.

Pressure wave: Pulsations or oscillations in the induction and exhaust systems caused by the opening and closing of the valves

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

Pressurized: Working under pressure

Presta valve: Presta valve

A bicycle tube valve whose stem has a small nut on top, which must be loosened during inflation, instead of a spring such as is found on the Schrader valve.

Pretensioner: A device that retracts the seat belt to tighten or take up slack in the wearer's belt. When a collision occurs or when brakes are applied, a seat belt with a pretensioner detects the stopping action and tightens the belt before the wearer is propelled forward. This holds the occupant more securely in the seat.

Preunit: An engine and gearbox that are not built together in the same casing. Preunit construction was common on earlier motorcycles

Prevention: See
Corrosion prevention

Previa: Click image for books on
Previa

A model of automobile manufactured by Toyota

Pre-wetting: The process of applying liquids to salt (before spreading salt on paved roads) to accelerate the ice melting process and prevent salt from bouncing off the road surface.

Price: See
Basic price
End-of-lease purchase price
Final purchase price
Fixed price selling
List price
Manufacturer's suggested retail price
One price selling
Purchase price
Retail Motor Gasoline Prices
Sticker price
Trade-in price

Price selling: See
Fixed price selling
One price selling

Prick punch: Small, sharp punch used to make punch marks on a metal surface

Primary: See
Ignition Primary

Primary air: Air introduced into a burner at the mixer head, which mixes with the gas before reaching the port(s).

Primary air inlet: One or more openings through which Primary air is admitted into a burner.

Primary and secondary roads: Primary roads are those designated by an agency to have a higher priority for plowing and sanding; secondary roads are those designated to have lower priority

Primary battery: A non-rechargeable battery consisting of one or more primary cells, used e.g., in portable radio receivers. Opposite to Secondary battery or Storage battery

Primary brake shoe: The Brake shoe that is first to press against the Brake drum. The other shoe is the secondary shoe. When both shoes are pressing against the drum, the amplification of forces is called servo action.

Primary catalytic converter: A small converter positioned close to the engine which quickly achieves the necessary operating temperature to reduce exhaust emissions during the warm-up period

Primary cell: An electric cell that converts chemical energy into electrical energy in an irreversible process unlike a secondary cell, it cannot be recharged

Primary chain: The chain of a primary drive

Primary circuit: The low Voltage (6 or 12 volts) path of the Ignition system which goes from the Positive pole of the Battery to the Primary windings of the Coil, through the Breaker points, and into the ground which leads back to the Negative pole of the Battery.

Primary coil: A tube-and-fin circular coil that contains a water glycol solution which surrounds the ignitor and burner. This coil is used in a water glycol gas forced-air furnace.

Primary compression: A term that is used in Two-stroke engines. Primary compression takes place in the Crankcase and is then pushed up into the Combustion chamber where Secondary compression takes place as the Piston squeezes the mixture. If the Crankcase seals are poor, primary compression will be reduced resulting in reduced Secondary compression so that it may be difficult to start the engine.

Primary compression ratio: The degree of compression achieved in the crankcase area below the piston of a two-stroke engine when the piston moves down and compresses the mixture supplied into the crankcase

Primary control: Device which directly controls operation of heating system.

Primary drive: A drive chain connecting the engine's crankshaft to its transmission

Primary forward brake shoe: The Brake shoe that is installed facing the front of the vehicle, it will be a self-energizing shoe.

Primary fuels: Fuels that can be used continuously. They can sustain the boiler sufficiently for the production of electricity.

Primary ignition: The low-voltage part of the ignition circuit, such as part of the ignition coil wiring, the pickup, electronic ignition module, and ECM. Compare Secondary ignition

Primary key: A key which operates all the locks of the car.
Also see
Secondary key

Primary magnetic field: A magnetic field of the primary winding

Primary pattern: The oscilloscope pattern of the primary circuit

Primary piston

The main piston in a tandem master cylinder
In a dual or tandem master cylinder, the piston against which the brake pedal or power booster pushrod bears.

Primary pressure: Also known as system pressure in Bosch continuous injection system

Primary pull-off diaphragm: Device that partially opens the choke when vacuum develops (i.e., when the engine starts), allowing more air to pass through the carburetor, thinning out the excessively rich idle mixture

Primary pump: An engine-driven oil pump feeding pressurized oil to the transmission and hydraulic control system

Primary recovery: The crude oil or natural gas recovered by any method that may be employed to produce them where the fluid enters the well bore by the action of natural reservoir pressure (energy or gravity).

Primary Safety control: A control responsive directly to flame properties; sensing the presence of flame and causing fuel to be shut off in the event of ignition or flame failure requiring manual reset.

Primary seal: The primary piston seal in a tandem master cylinder

Primary shaft: See
Clutch shaft

Primary shoe

The shoe of a brake drum system which pivots outwards into the approaching drum. The British term is Leading shoe
The shoe in a duo-servo drum brake that transfers part of its braking force to the secondary shoe
The shoe in a servo brake that transfers a portion of its stopping power to the secondary shoe. The primary shoe provides nearly 30% of the total stopping power.

Primary structure component: Any structural component which, if it collapsed, could make the car uncontrollable or would seriously reduce occupant safety in a crash

Primary terminal: The clip found inside the Distributor which allows electric Current to pass from the points to the Condenser and provides the Insulation to keep the Current from contacting other metal parts.

Primary valve: The valve which controls the Primary V-pulley

Primary V-pulley: (CYT) The pulley which is driven by the engine via a clutch; one of its halves can be slid hydraulically, thus varying the diameter of the steel thrust belt track and changing the transmission ratio

Primary winding: The low Voltage (6 or 12 volt) windings in Ignition coil, the primary winding is heavy wire; Secondary winding uses fine wire.

Primary windings: The low Voltage (6 or 12 volt) windings in Ignition coil, the primary winding is heavy wire; secondary winding uses fine wire.

Primary wire: See
Primary wires.

Primary wires: The wiring which serves the low Voltage part of the Ignition system. Wiring from Battery to switch, Resistor, Ignition coil, Distributor points.

Prime

To paint bare metal with Primer to prevent rusting. A second color (often different from the prime color) is painted over the primer.
Pronounced PREEM, a stage in a bicycle race.
To fill a machine (e.g., a pump) with the necessary fluid before starting, in order to improve its sealing qualities.
To put fuel in the float chamber of a carburetor to ease the starting of an engine

Prime coat: A Primer or surfacer applied to the old paint or bare metal before the Finish coat is applied.

Prime mover: The engine, turbine, water wheel, or similar machine that drives an electric generator; or, for reporting purposes, a device that converts energy to electricity directly (e.g., photovoltaic solar and fuel cells).

Primer: The surfacer that acts as a bond between the bare metal surface or old paint and the color Coat and designed to give rust protection.
Also See
Anti-chip coating
Electrophoretic primer
Etching primer
Etch primer
Factory primer
Shop primer
Weld-through primer
Zinc-rich primer

Primer bath: A container filled with Primer into which a metal object is submerged. This painting procedure is faster than spray painting and will cover better. The disadvantage is that a lot of primer is required and the metal must be bare of anything else (i.e., glass, rubber, cloth)

Primer filler: A special primer used to cover fine cracks

Primer oven: A painting oven used to dry the coats of primer

Primer surfacer: The material for the resilient coating underneath the top paint coat which provides corrosion protection, protects the paint system from chipping caused by gravel, provides a smooth surface for the top paint coat, and serves as an adhesion promoter. A primer that contains a lot of solid material to fill small imperfections in the substrate (primer-surfacer must be sanded before applying paint over them)

Princess: Click image for books on
Princess

An automobile manufactured by British-Leyland

Principal: See
Dealer principal

Principle: See
Plunger principle
Pulse air principle
Ricardo principle
Select-low Principle
Valve principle

Printed circuit: An electrical circuit made by connecting the units with electrically conductive lines printed on a panel, this eliminates actual wire and the task of connecting it.

Printed circuit board: (pcb) A thin plastic insulating board on one or both sides of which the components and connections of an electronic circuit are formed by etching in a metallic coating or electrodeposition

Priorities List: See
National Priorities List

Prise off: To remove a stubborn object with a lever

Private Carrier: A business which operates trucks primarily for the purpose of transporting its own products and raw materials. The principle business activity of a private carrier is not transportation. Compare For-Hire Carrier.

Private fueling facility: A fueling facility which normally services only fleets and is not open to the general public.

Private Street: A privately owned and maintained access provided for by a tract, easement or other legal means, typically serving three or more potential dwelling units.

Prix: See
Grand Prix

PRND: Acronym for the order in which an automatic Transmission is displayed to the Driver and stands for Park, Reverse, Neutral, and Drive. Sometimes, two or more drive positions will be displayed as D1 and D2.

PRNDL: Acronym for the order in which an automatic Transmission is displayed to the Driver and stands for Park, Reverse, Neutral, Drive, and Low. Sometimes, the Low may be divided into 3, 2, 1.

Probe

A pointed tool, like an icepick. It is used to determine the extent of injuries during the tire inspection.
An Awl.
A measuring sensor, usually long and thin to gain access to narrow cavities.

Also See
Lambda probe.
Click image for books on
Ford Probe

A model of automobile manufactured by Ford

Process: See
Basic Process
Batch Process
Bessemer Process
Betts Process
Bredigs Arc Process
Cailletets Process
Catalan Process
CBR process
Electrolytic Process
Electrochemical Process
Electrodeposition Process
Jet process
Lost-foam casting process
Plasma spray process
Pulse Combustion Process
Reverse process
Sendzimir process
VERTAC-process

Process Annealing: Heating a ferrous alloy to a temperature close to, but below, the lower limit of the transformation range and then cooling, in order to soften the alloy for further cold working.

Process cooling and refrigeration: The direct process end use in which energy is used to lower the temperature of substances involved in the manufacturing process. Examples include freezing processed meats for later sale in the food industry and lowering the temperature of chemical feedstocks below ambient temperature for use in reactions in the chemical industries. Not included are uses such as air-conditioning for personal comfort and cafeteria refrigeration.

Processed gas: Natural gas that has gone through a processing plant.

Process fuel: All energy consumed in the acquisition, processing, and transportation of energy. Quantifiable process fuel includes three categories: natural gas lease and plant operations, natural gas pipeline operations, and oil refinery operations.

Processing: See
Ceramics Processing

Processing gain: The volumetric amount by which total output is greater than input for a given period of time. This difference is due to the processing of crude oil into products which, in total, have a lower specific gravity than the crude oil processed.

Processing loss: The volumetric amount by which total refinery output is less than input for a given period of time. This difference is due to the processing of crude oil into products which, in total, have a higher specific gravity than the crude oil processed.

Process tube: Length of tubing fastened to hermetic unit dome, used for servicing unit.

Procon-ten: A safety system developed by Audi which makes use of the relative displacement of the engine during a frontal collision; steel cables pull the steering wheel away from the driver and increase the seat belt tension

Produced: See
North American produced

Producer: See
Domestic Vehicle Producer

Product: See
Branded Product
Car Care Product
Corrosion product
Nonbranded Product
Nonfungible Product

Product carrier: A tanker used to carry refined oil products. Normally four different grades of oil can be handled simultaneously.

Product design: The process of planning the product's specifications.

Production car: A vehicle model that has been assembled for sale to the general public as opposed to a concept vehicle that is not available to be purchased. Also called production model.

Production engineering: Planning and control of the mechanical means of changing the shape, condition of materials toward greater effectiveness and value.

Production line: A system of assembly in which the parts of an end product are transported by a conveyor past a number of sites where the parts are modified without stopping the conveyor

Production model: A vehicle manufactured by a mass-production process. A vehicle model that has been assembled for sale to the general public as opposed to a concept vehicle that is not available to be purchased. Also called production car.

Production motorcycle: Bikes manufacturer produce to sell to the general public rather than bikes built specifically for racers

Production plant liquids: The volume of liquids removed from natural gas in natural gas processing plants or cycling plants during the year.

Production retread shop: A shop which schedules its production not on the basis of day-to-day orders but rather on long runs of purchased Tire casings in order to secure the lowest cost per unit.

Production vehicle: A vehicle manufactured by a mass-production process. A vehicle model that has been assembled for sale to the general public as opposed to a concept vehicle that is not available to be purchased. Also called production model.

Productivity: Relative measure of output per labor and/or machine output.

Product line: A series of different products made by the same company which form a group (such as different models of cars)

Product planning: A function whereby an enterprise is responsible for the efficient, planning, scheduling and coordination of production activities.

Product range: A series of different products made by the same company which form a group (such as different models of cars)

Products: See
Miscellaneous Petroleum Products
Petroleum Products
Plant Products
Refined Petroleum Products

Product testing: Rigorous methods whereby a product's quality and durability are measured.

Professional drivers: Drivers whose main income is from driving, such as bus, coach and haulage drivers

Profile

The side view of something.
The aspect ratio of a tire.

Also See
Cam profile
Low profile
Tread profile

Profile depth: See
Tread depth. Compare Aspect ratio

Profile ignition pickup: (PIP) a Hall Effect vane switch that furnishes crankshaft position data to the Ford EEC-IV processor

Profit: See
Operating profit

Program: A series of instructions used by the computer.
Also see
Alternative Fuels Utilization Program
National Low-Emission Vehicle Program
Scientific Research And Experimental Development Program

Program cars: Automobiles sold by manufacturers for fleet use. Usually applies to very large fleets, such as those of car rental companies.

Program comparison and identification: (PCI) A system that identifies a radio station and compares stations to find the station which offers the strongest signal

Programmable controller: A digitally operating electronic system designed for use in an environment, which uses a programmable memory for the internal storage of user-oriented instructions for implementing specific functions such as logic, sequencing, timing, counting and arithmetic to control, through digital or analog inputs and outputs, various types of processes or machines.

Programmable read only memory

(PROM) An electronic component which can be specifically programmed to the design of each car model to control the M/C solenoid. Plugs into the Electronic Control Module (ECM). Also called an Engine calibration unit
A non-volatile memory that stores information permanently. This type of memory cannot be written to. Once programmed, it cannot be altered.

Programmed Fuel Injection: (PGM-FI) Honda's fuel injection system for the Accord, Civic, Civic CRX, and Prelude

Programmer: The module that controls blower speed, the air mix door, vacuum diaphragms and other devices in a system equipped with automatic temperature control

Program objectives: A consensus of what has been determined to be the most marketable product for a given model year.

Progressive carburetor: See
Compound carburetor

Progressive linkage: A Carburetor Linkage designed to open the Throttle valves of multiple Carburetors. It opens one to start with and when a certain opening point is reached, it will start to open the others.

Progressively wound valve spring: A valve spring with variable spacing between its coils which helps to improve responsiveness and thus to reduce the load on the valve train

Progressive rate spring: A spring with an increasing spring constant. For example, if the first inch of spring motion requires 100 pounds of force, the second inch would require more than an additional 100 pounds, and the third inch would require still more. Progressive-rate springs become stiffer as they are compressed, unlike single-rate springs, which have a fixed spring rate.

Progressive spring: See
Progressive rate spring.

Progressive suspension: A system in which the Suspension stiffness changes depending on the amount of change required. On light bumps, the suspension is soft; but on greater bumps, the suspension is stiff.

Progressive transmission: An older version of a Manual transmission. When you wanted to go from Low gear to the highest gear, you had to go through all the gears in between. Likewise when you wanted to go from the highest gear to the lowest, you had to proceed through all the Intermediate gears.

Progressive valve spring: A valve spring with variable spacing between its coils which helps to improve responsiveness and thus to reduce the load on the valve train

Projected core/insulator nose: An insulator tip that extends beyond the end of the spark plug shell

Projected spark position: The amount the spark plug gap projects into the combustion chamber 1 mm for the slightly projected spark position in older engines and 3 mm for the normally projected spark position in modern engines

Projection: See
Back Projection

Projection welding: Resistance welding method

PROM: Acronym for Programmable Read Only Memory. PROM contains permanent information about how components should perform under various operating conditions

Promoter: A substance embedded in the washcoat on catalyst substrates that serves to enhance catalytic efficiency

Prony brake

A device using a Friction brake to measure the Horsepower output of an engine.
A simple mechanical device, normally made of wood with an adjustable leather strap, that is used to test for the torque output of an electric motor. The prony brake loads the motor and a spring scale attached to it gives a relatively accurate measurement of torque.

Proof load: A test load that a fastener must undergo without showing significant deformation. It is usually 90% of yield strength.

Prop: See
Gas prop

Propane

(C₃H₈)

A colorless, flammable gas which is a Petroleum product, similar to and often mixed with Butane. It is useful as an engine fuel or for cooking and heating. In Canada this is the term used for LPG.
A flammable, heavier-than-air gas used in the Halide torch leak detector
Volatile hydrocarbon used as a fuel or as a refrigerant.

Also See
Consumer grade propane

Propane air: A mixture of Propane and air resulting in a gaseous fuel suitable for pipeline distribution.

Propane MD-5: A special grade of liquefied petroleum gas composed of a minimum of 90 percent liquid volume of propane (C3H8) and a maximum of 5 percent liquid volume of Propylene (C3H6).

Propellant: See
Solid propellant

Propeller: The impeller of a pump, characterized by a small number of blades of double curvature; propellers are generally axial-flow impellers, seldom mixed-flow ones.
Also see
Bow Propeller
Divided propeller shaft

Propeller pump: The impeller of a pump, characterized by a small number of blades of double curvature; propellers are generally axial-flow impellers, seldom mixed-flow ones

Propeller shaft: British term for Driveshaft. The shaft connecting the Transmission Output shaft to the Differential pinion shaft.

Also See
Composite propeller shaft
Divided propeller shaft

Propeller shaft safety strap: See
Driveshaft safety strap.

Propelling power: The force with which a vehicle moves; the pulling force; depends not only on engine power and torque, but also on the amount of friction between driving wheels and road surface

Proper proportion of air and fuel: One of the essential factors in a Combustion engine (Fuel, Air, Proper proportion of mixture, Compression, Timing, Spark).

Properties: See
Run-flat properties

Property: See
Intellectual property rights

Property rights: See
Intellectual property rights

Proper ventilation: In general, the dilution of a flammable gas/vapor with air to a point safely below its lower explosive limit (LEL). As applied to this standard, a sufficient or adequate supply of fresh air and proper exhaust to outdoors or to a safe location with a sufficiently-vigorous and properly distributed air circulation to ensure that the flammable gas/vapor concentration in all parts of the enclosure will be below 25 percent of the LEL at all times.

Proportion: See
Proper proportion of air and fuel

Proportional: Being in the proper relative quantity or balance.

Proportional Brake Control: See
Load Proportional Brake Control

Proportional load synchromesh: See
Locking synchromesh

Proportioning: The act of distributing something (e.g., brake fluid) to several components in equal measures.

Also See
Brake proportioning valve
Load-sensitive proportioning valve

Proportioning valve

Any valve which limits pressure in a system, e.g., in a hydraulic circuit, in automatic transmissions, in pneumatic suspension systems, etc.
The valve used in the rear brake line of some cars with front disc and rear drum brakes. When braking gently, pressure is about equal front and rear; as pedal pressure is increased, the limiting valve controls and finally limits pressure to the rear wheels to prevent rear wheel lockup during heavy braking. The British term for proportioning valve is pressure limiting valve.
A hydraulic valve that reduces pressure to the rear wheel to obtain balanced braking.
A hydraulic control valve located in the circuit to the rear wheels which limits the amount of pressure to the rear brakes to prevent wheel lock-up during panic stops

Also See
Adjustable-port Proportioning Valve
Brake proportioning valve
Load Sensing Proportioning Valve
Load-sensitive proportioning valve

Proportion Of Air And Fuel: See
Proper Proportion Of Air And Fuel

Proprietorship: See
Sole Proprietorship

Propshaft: Abbreviation for Propeller shaft.

Also See
Divided propshaft
Driveshaft

Prop shaft: Abbreviation for Propeller shaft.
Also see
Driveshaft.

Propulsion: See
Hybrid propulsion

Propulsive power: The force with which a vehicle moves; the pulling force; depends not only on engine power and torque, but also on the amount of friction between driving wheels and road surface

Prop up: To secure the hood, trunk, or liftgate in the open position using the hood support rod.

Propylene: (C₃H₆) An Olefinic hydrocarbon recovered from refinery processes or petrochemical processes.

Prospector's pick: A tool with a long handle (usually made of wood) to which a long curved piece of iron has been attached. At one end of the iron is a point while a blade shape is at the other end.

Prost, Alain: Alain Prost of France is a four-time World Driving Champion. He is the only French Grand Prix driver to win the World Championship in the modern era (1951 through the present). He has won more races than any other driver in Grand Prix racing history. And his 51 wins are a record that will likely stand for a long time.

Protection: See
Canadian Environmental Protection Act
Cathodic protection
Corrosion protection
Edge protection
Electrolytic protection
Mechanical Protection
Rust protection
Underbody protection

Protection Act: See
Canadian Environmental Protection Act

Protection Agency: See
Environmental Protection Agency
U.S. Environmental Protection Agency

Protection Agency Certification Files: See
Environmental Protection Agency Certification Files

Protection System: See
Low-refrigerant Protection System

Protective coat: A layer or layers applied to a surface to provide corrosion protection

Protective coating: A layer or layers applied to a surface to provide corrosion protection

Protective System: See
Balanced Protective System
Beard Protective System
Biased Protective System
Bowden-Thomson Protective System

Protector: See
Circuit Protector
Door protector
Nose protector
Overload Protector
Thermal Protector

Protector, circuit: Electrical device which will open an electrical circuit if excessive electrical conditions occur.

Protector washer: A filter disc between the primary piston and primary seal which supports and protects the primary seal when the brake system is under pressure

Protocol: See
Kyoto Protocol
Montreal Protocol

Proton: A positive charge particle forming part of the atom.

Proton exchange membrane: (PEM) The separating layer in a PEM fuel cell that acts as an electrolyte (which is proton conducting) as well as a barrier film separating the hydrogen-rich feed in the cathode compartment of the cell from the oxygen-rich anode side.

Proton exchange membrane fuel cell: (PEMFC or PEFC) A type of acid based fuel cell in which the exchange of protons (H+) from the anode to the cathode is achieved by a solid, aqueous membrane impregnated with an appropriate acid. The electrolyte is a called a proton-exchange membrane (PEM). The fuel cells typically run at low temperatures (less than 100°C) and pressures (< 5 atm).

Prototype: The test model of a new car design that is intended to be produced in quantity.

Also See
Camel Grand Touring Prototype
Concept car
Mock-up

Proud: Something that projects up slightly from the surrounding surface. Something not Flush. Also called Standing proud or Stand proud

Proved pilot: A pilot flame supervised by a primary safety control.

Provider: See
Alternative-Fuel Provider

Pry: See
Inside pry spoon

Pry spoon: See
Inside pry spoon