DICTIONARY OF AUTOMOTIVE TERMS - "Po"

POA
Acronym for Pilot operated absolute valve used in some air conditioning systems
POA suction throttling valve
A term standing for pilot operated absolute and is a modification of a suction throttling valve which has a metal bellows with a vacuum instead of a diaphragm; it provides more accurate evaporator pressure control, allowing for lower evaporator temperatures without cone icing
Pocket
See
Pocket caliper
A small slide-type caliper for inside and outside measurement up to about 100 mm or 4 inches
Pocket Compressor
See
Pocket slide caliper
A small slide-type caliper for inside and outside measurement up to about 100 mm or 4 inches
Pod
A housing for a gauge mounted on the dash.
Also see
Pod filter
A foam filter which is like a sock (open at one end and closed at the other) and is clamped on the horn of a carburetor
POE
Acronym for Port of Entry
Point
See
Point Depression
See
Point file
See
Point gap
The space between the Contact points when they are fully open. The distance of the gap will determine the effectiveness of the points.
Point gauge
See
Point injection
See
Points
Two or more metal terminals, located inside the distributor on vehicles with non-electronic ignitions. These terminals are brought into contact and then separated by the movement of the cam wheel on the rotating distributor shaft. The points regulate the intensity and duration of the current that is conducted to each spark plug by interrupting the flow of current from the coil as they open and close. Also called Contact points, Breaker points, or ignition points.
Also see
Points file
A thin, fine-toothed file for cleaning and smoothing off the piles on contact breaker points
Points gap
A gap between the contact breaker points when fully open; measured with a feeler gauge
Point steering
See
Point Valve
See
Poison
See
Poisoning
See
Poke
A colloquial term for power or acceleration
Polarity
  1. Indicates if the Pole shoes are so magnetized as to make Current low in a direction compatible with the direction of flow as set by the Battery.
  2. Indicates if the end of a Magnet is the North or South pole (N or S).
  3. Indicates if the Battery terminal (either one) is positive or negative (plus or minus) (+ or -).
  4. The terms (positive, negative, north, and south) that indicate the direction of current and flux flow in electrical and magnetic circuits at any given instant
Also see
Polarization
See
Polarization curve
Typically a plot of fuel cell voltage as a function of current density (V vs. A/cm2 or similar units). The curve is obtained under standard conditions so that fuel cell performance can be compared between different cell designs, and may be obtained by either a single cell or a stack test.
Polarization resistance
The transition resistance between the electrodes and the electrolyte; part of the internal resistance of a battery. Compare Internal resistance
Polarizing
The process of sending a quick surge of Current through the Field windings of the Generator in a direction that will cause the Pole shoes to assume the correct Polarity. This will insure that the generator will cause Current to flow in the same direction as normal.
Polar moment of inertia
The Resistance of an object to rotational acceleration. When the mass of an object is distributed far from its axis of rotation, the object is said to have a high polar moment of inertia. When the mass distribution is close to the axis of rotation, it has a low polar moment of inertia. A Mid-engined car has most of its mass within its Wheelbase, contributing to a low polar moment of inertia, which, in turn, improves cornering turn-in.
Also see
Pole
  1. One end, either North or South, of a Magnet.
  2. A post or long shaft.
  3. The best starting position in an auto race. It is the inside space on the first row of drivers. Most races begin with the cars in a formation of rows of two. Most events begin with a standing start or a rolling start.
Also see
Pole Magnetic
See
Pole piece
A soft magnetic core of the inductive winding in a magnetic pick-up assembly; stator
Pole position
The best starting position in an auto race. It is the inside space on the first row of drivers. Most races begin with the cars in a formation of rows of two. Most events begin with a standing start or a rolling start.
Poles cargo
This cargo category includes processed wood, like 2x4's, plywood, pulpwood, firewood, and new pallets, fresh from the factory, but not used empty crates. Wood chips, wood residuals, and bark are solids in bulk.
Pole shoe
See
Pole shoes
Metal pieces about which the Field coil windings are placed, when Current passes through the windings, the pole shoes become powerful Magnets, example Pole shoes in a Generator or Starter motor.
Pole Trailers
A logging trailer. Usually has bunks for holding logs. The center portion of the trailer may be adjustable in order to accommodate loads of different lengths.
Pole Truck
  1. A winch truck with lifting equipment for lifting poles in oilfield service and contracting. It can have an A-frame.
  2. A flatbed truck with bunks.
Polish
  1. A substance like wax used to make the exterior paint shine or gloss.
  2. The act of making the paint shine.
  3. To make smooth or lustrous by friction with a very fine abrasive.
  4. To remove the minor obstructions in the exhaust flow. A term sometimes coupled with Porting, as in porting and polishing or port and polish. This is generally a process of Blueprinting a Two-stroke engine so that the Intake and Exhaust ports are polished and have no obstructions in the flow of Fuel-air mixture or Exhaust gases. In this way the engine generally has more performance. A problem may arise when an individual port has been polished too much.
Also see
Polishing
See
Polishing barrel
A barrel used for a polishing process in which the aluminum surface is smoothed in the presence of metallic or ceramic shot by a rotating movement of the barrel
Pollutant
Hydrocarbons, carbon monoxide, and nitrogen oxides.
Also see
Pollutant Discharge Elimination System
National Pollutant Discharge Elimination System
Pollution
The impairment (reduction) of water quality by agriculture, domestic, or industrial wastes (including thermal and radioactive wastes) to such a degree as to hinder any beneficial use of the water or render it offensive to the senses of sight, taste, or smell or when sufficient amounts of waste creates or poses a potential threat to human health or the environment.
Also see
Polycarbonate
(PC) A polyester polymer in which the repeating structural unit in the chain is of the carbonate type; used for bumpers, body and roof panels
Polychlorinated biphenyl
(PCB) Dielectric fluid used in capacitors and transformers that is very toxic. Use of PCB in transformers and capacitors is strictly regulated by the Environmental Protection Agency.
Polycyclic Organic Matter
(POM) A class of air toxics defined in the US Clean Air Act as compounds with more than one Benzene ring and a boiling point of 100°C and higher. Includes practically all of diesel PAH material.
Polyellipsoidal
A curve which is an ellipse in every direction so that the light of the bulb which is positioned at the focal point will bounce into the same forward direction.
Polyellipsoidal headlight
A headlight with a gas discharge lamp and a polyellipsoidal reflector
Polyester
A synthetic fiber.
Polyester filler
A body repair material for smoothing dents in body panels; includes a resin base filler paste and a catalyst which is added to the base filler and hardens by chemical reaction
Polyester powder
A powder used for electrostatic powder coating
Polyethylene
(PE) A polymer prepared by the polymerization of ethylene as the sole monomer; very resistant to chemical attack. High-density polyethylene (HDPE) is used, e.g., for blow-molded parts such as tanks for fuel, coolant, washer and brake fluid; Low-density polyethylene (LDPE) is used for plastic film and sheet
Also see
Polyglycote
A paint finish used on some vehicles and was advertised to require no cleaning except for an occasional wash.
See
Polymer
A material consisting of large units (molecules) made by joining many smaller building blocks (simple molecules). Usually used to describe synthetic rubber.
Polymer alloy
A mixture of two or more different compatible polymers
Polymer coating
A Coating that prevents paint from oxidizing and so protects a vehicle from premature fading and rusting. Professionally applied, it will last up to three years.
Polymerization
The bonding of two or more monomers (by chemical reaction) to produce a polymer. Plastic parts produced from specific polymer alloys usually give better performance in respect to thermal and mechanical properties as compared to those of parts consisting of the respective individual components
Polymethyl methacrylate
(PMMA) A thermoplastic polymer derived from methylacrylate; transparent solid with excellent optical qualities and weather resistance; typical automotive applications are the lenses of rear lights. Also called Perspex
Polynuclear Aromatic Hydrocarbons
(PAH); Aromatic hydrocarbons with two or more (up to five or six) Benzene rings joined in various, more or less clustered forms.
Polyphase motor
Electrical motor designed to be used with a three-or four-phase electrical circuit.
Polyphenylene oxide
(PPO) The characteristics of this plastic are high impact strength, good thermal and dimensional stability as well as excellent flame-resistance
Polypropylene (PP)
An extremely versatile plastic, available in many grades and also as a copolymer (ethylene/propylene). PP has the lowest density of all thermoplastics (900 kg per cubic meter) and is characterized by excellent strength, stiffness, fatigue, and chemical resistance. Also used in fabric because it is extremely hydrophobic, fast drying, does not absorb moisture, lightweight, strong, and abrasion resistant.
Polystyrene
  1. A polymer of styrene that is a rigid, transparent thermoplastic with good physical and electrical insulating properties, used in molded products, foams, and sheet materials.
  2. Plastic used as an insulation in some refrigerated structures.
Polysulfide
Synthetic rubber compounds used in adhesives, coatings and sealers. When cured, they are almost unaffected by aliphatic or aromatic solvents; and retain flexibility and shock resistance at low temperature. Flow characteristics, odor and high relative cost limit their use as adhesives to very specialized applications. High performance sealers of this base are widely used for aircraft and marine requirements
Polytetrafluoroethylene
(PTFE) The major advantages of this material are its excellent chemical resistance and its extremely low coefficient of friction; automotive uses are parts where these characteristics are relevant, such as in valve stem seals, friction bearings, and joints
Polyurethane (PUR)
  1. A thermoplastic material with high strength, good chemical and abrasion resistance; used mainly for foamed reaction injection moldings and for adhesives, such as for flush-bonded body glass
  2. Any synthetic rubber polymers produced from the polymerization of an HO and NCO group from two different compounds. Often used in insulation and molded products.
Polyurethane blades
A plow blade composed of hard plastic that provides more flexible blade action over road obstructions than steel blades
Polyurethane paint
A type of two-pack paint based on polyurethane substances
Polyurethane powder
A powder used for electrostatic powder coating
Poly-V-belt
A drive belt with multiple Vs; flat, similar to the toothed belts used as timing belts, but with lengthwise V-shaped ribs rather than transverse cogs; used increasingly on new engines instead of conventional V-belts
Polyvinyl chloride
(PVC)
  1. A polymer of vinyl chloride. Tasteless, odorless, insoluble in most organic solvents. A member of the family vinyl resin, used in soft flexible films for food packaging and in molded rigid products, such as pipes, fibers, upholstery, and bristles.
  2. Both plasticized and unplasticized PVC types are marked by good weathering resistance, excellent electrical insulation properties, and good surface properties; they are self-extinguishing
POM
Acronym for Polycyclic Organic Matter
Pony Axle
Colloquial term for a smaller diameter wheel attached to a lift axle.
Poop
A superstructure fitted at the after end of the upper deck of a ship
Ponded roof
Flat roof designed to hold a quantity of water which acts as a cooling device.
Pontiac
Pontiac

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Pontiac

A vehicle brand of which the Safari for 1955-57 are milestone cars. The GTO for 1964-69 are milestone cars.
Also see

Pony car
Small, sporty car along the lines of the Mustang, Firebird, Camaro, etc. especially of the 1960-80.
Poor opacity
A paint fault in which the color of underlying coats or fillers remains visible through the topcoat; may be caused by insufficient paint thickness, overthinning, etc.
Pop
See
Pop-off valve
A one-way valve that opens to the atmosphere above a certain set pressure to relieve excessive internal pressure buildup; often used with a turbocharger installation to limit boost pressure to the engine.
Popper
See
Poppet valve
A valve structure consisting of a circular head with an elongated stem attached in the center, very much like the shape of a mushroom with a flat top. It is designed to open and close a circular hole or Port. Its name comes from the fact that it pops up and down. In engines, it is the valve used to open and close the Valve port entrances to the engine Cylinders.
Popping
See
Popping back
See
Pop rivet
Pop rivet

Pop rivet

  1. A type of tubular rivet which initially has a hard steel pin (like a nail) passing through it; when the pop rivet is fitted with a pop rivet gun, the head of the pin expands the inner end of the tubular rivet, closing it; the head of the pin then snaps off; used when a joint can be accessed from only one side.
  2. A blind fastener which has a self-contained mandrel which permits the formation of an upset on the blind end of the rivet and expansion of the rivet shank. The mandrel is pulled into or against the body, breaking at or near the junction of the mandrel shank and its upset end.

Pop riveter
Pop riveter

Pop riveter

A tool into which a pop rivet is inserted so that as the handles are squeezed, the end of the rivet shank is mushroomed to secure the rivet in place. Also called a pop rivet gun.
Pop tester
An injector testing tool used for measuring opening pressure, leakoff pressure, and spray patterns of injectors
Populaire
A randonneur bicycle event under the regulations and pace of a standard brevet which is less than 200 kilometers.
Pop-up
A towable tent that pops up when parked to expand its space. These types have a furnace, three way refrigerator, a/c, and more options.
Pop-up headlights
See
Porcelain
  1. The material used to insulate the center Electrode of a Spark plug, it is hard and resistant to damage by heat.
  2. Ceramic china-like coating applied to steel surfaces.
Porcelain enamel
A glassy material obtained by melting a mixture of inorganic materials; this can then be applied in one or more layers on a metal surface to which it is firmly bonded after firing; typical automotive applications are for badges and trim. The British term is vitreous enamel
Porch
See
Pore
A small opening in a surface
Porosity
Presence of gas pockets or voids in the metal.
Porous
Permeable to air or fluids
Porsche
Porsche

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Porsche

A German vehicle brand of which the Series 356 for 1949-64 are milestone cars. The 356C for 1965 is a milestone car. Includes 911 (1964-current), 924 (1976-88), 928 (1977-95), 944 (1982-91), 968 (1992-95), Boxster (1997-current), Carrera GT (2004-05), Cayenne (2003-06), and Cayman (2006-07)
Porsche-type synchromesh
A sophisticated synchromesh technology depending on the frictional forces created by a spreading synchronizer ring
Port
  1. An opening in an engine Cylinder block for Exhaust and Intake valves and water connections.
  2. To smooth out, align, and somewhat enlarge the Intake passageway to the valves or intake chambers (especially in Two-stroke engines).
  3. A small hole in the Master brake cylinder to permit fluid to return to the reservoir.
  4. Any opening in a burner head through which gas or gas-air mixture is discharged for ignition.
  5. The left-hand side of a ship when facing forward.
Also see
Portable service cylinder
Container used to store refrigerant. Two most common types are disposable and refillable.
Port area
The cross-section area of the port of a two-stroke engine; this value is one of the factors determining the gas flow and the power of a two-stroke engine
Port bar
If the ports of the two-stroke engine have to be exceptionally wide, as in the case of the exhaust, a port bar is sometimes formed vertically across the port to give support to the rings, which might otherwise expand into the port and be jammed and broken
Port bridge
If the ports of the two-stroke engine have to be exceptionally wide, as in the case of the exhaust, a port bar is sometimes formed vertically across the port to give support to the rings, which might otherwise expand into the port and be jammed and broken
Port cover
See
Ported EGR valve
Operated by a vacuum signal from the carburetor EGR port. The port signal actuates the valve diaphragm. As vacuum increases, spring pressure is overcome, opening the valve and allowing EGR flow. The amount of the flow is dependent on the position of the tapered pintle or poppet whose position reflects the strength of the vacuum signal
Ported vacuum
A slot-type port located right at the throttle plates, used for controlling various devices that must work in proportion to throttle plate opening, such as the EGR valve. When the throttle plates are closed at idle, there is virtually no vacuum signal at this slop. But as the throttle plates open during acceleration, they expose the slot to a progressively increasing amount of intake manifold vacuum
Ported vacuum advance
(PVA) A series of restriction devices between the distributor advance unit and the carburetor advance port to ensure that there is no vacuum advance during idle, but increasing ignition advance as the throttle opens
Ported vacuum switch
(PVS) a temperature actuated switch that changes vacuum connections when the coolant temperature changes (originally used to switch spark port vacuum; now used for any vacuum switching function that requires coolant temperature sensing)
Port fuel injection
(PFI) A type of fuel injection with at least one injector mounted in the Intake port(s) of each cylinder. Usually the injector is mounted on the air Intake manifold close to the port. Port fuel injection improves fuel distribution and allows greater flexibility in intake-manifold design, which can contribute to improved engine breathing. Also called Multi-point injection
Porthole
A styling accessory popularized by the Buicks of the early 1950s where three or four round chrome surrounds were fitted to the sides of both fenders for decorative purposes; this trim detail was soon imitated by other manufacturers and was offered as an option for many models, even in Europe. The T-bird had a porthole window on each the rear sail panels.
Port induction
See
Port Injection
See
Port of Entry
(POE) Each state or province has a number of check stops to be sure of compliance of commercial carriers to meet cargo and weight restriction.
Port timing
In 2-stroke engines the critical moment when ports are covered or uncovered by the piston
Pos
Abbreviation for Positive ground.
Position
See
Position sensor
See
Position welding
See
Positioning Satellite
See
Positive camber
See
Positive caster
When an imaginary line extending through the steering axis cuts the wheel axis ahead of the extended vertical axis through the wheel center.
Also see
Positive clutch
See
Positive connections
Connections in an electric circuit out of which electricity constantly flows. The positive connections out of which electricity flows may also be termed that into which electrons flow; and the negative connection into which electrons flow; and the negative connection into which the electricity flows may be considered that pole out of which the electrons flow.
Positive crankcase ventilation
(PCV) A process introduced in 1963 for preventing the buildup of harmful acid-producing combustion gases within the crankcase.
Also see
Positive crankcase ventilation system
(PCV) A process for preventing the buildup of harmful acid-producing combustion gases within the crankcase.
Also see
Positive crankcase ventilation valve
(PCVV) a one-way valve which controls the flow of vapors from the crankcase into the engine
Positive displacement compressor
A Pump which provides a measured amount of gas or liquid per stroke or cycle and requires some form of mechanical drive arrangement, usually a belt drive from the crankshaft; typical positive displacement compressors are piston compressors, roots compressors and vane-type compressors
Positive electrode
The Positive plate of a battery
Positive ground
An automotive electrical system where the negative post of the battery was the hot wire and the positive post was connected to the frame of the vehicle. Opposite to Negative ground.
Positive offset
  1. A steering geometry layout where the steering axis cuts the wheel axis at or below the wheel center plane.
  2. The distance between the mounting face of a disc and the wheel centerline; the offset is referred to as positive when the inner attachment face of the wheel disc is shifted towards the outer side of the wheel. The opposite is Negative offset
Positive plate
The chocolate-colored plate during battery discharge which acts as cathode. The opposite to negative plate
Positive pole
The point away from which an electrical Current flows through the circuit. It is designated by a plus sign (+).
Positive temperature coefficient
(PTC) a thermistor (temperature sensor) whose resistance increases as the temperature increase. The opposite of a negative temperature coefficient (NTC) thermistor
Positive temperature coefficient thermistor
(PTC) Electronic thermistor which increases in resistance as temperature increases.
Positive terminal
The terminal (such as that on the Battery), to which the Current flows. It is usually marked with the letters pos or a plus sign (+) and is usually red.
Positive Voltage
See
Possum Belly Trailer
A livestock trailer.
Post
  1. The round, tapered lead posts protruding above the top of the Battery to which the battery cables are attached.
  2. The pillars which support the roof on a car.
  3. The insert tube to which the seat of a bicycle is attached.
Also see
Post-combustion treatment
See
Postheating
  1. Temperature to which a metal is heated after an operation has been performed on the metal (welding, cutting, forming, etc.).
  2. The heating of glow plugs after the engine is started to prevent blue smoke and misfiring during the warm-up phase
Post-ignition
The ignition of the air-fuel mixture after the electrical ignition has been shut off
Post Roof
See
Pot
  1. A colloquial term for Carburetor.
  2. An abbreviation for a Potentiometer, also called a rheostat
  3. A cylinder.
Also see
Potassium permanganate
Used in carbon filters to help reduce odors.
Potato chipped wheel
A bicycle wheel which has been damaged so that it is bent like a potato chip. Also called a taco wheel for a similar reason.
Potato trailer
A hopper bottom or a live bed truck used to carry potatoes.
Potato Truck
A hopper bottom or a live bed truck used to carry potatoes.
Potential, electrical
Electrical force which moves, or attempts to move, electrons along a conductor or resistance.
Potential relay
Electrical switch which opens on high voltage and closes on low voltage.
Pothole
A deep hole in the surface of a road.
Pothole Repair
The winter is tough on roads and causes many potholes. The pothole area is excavated and then filled with asphalt. The entire operation takes minutes for one pothole, but workers could be on a single road repairing potholes for multiple days, depending on the severity of the potholes.
Pot joint
A universal joint in which the rollers or balls can move freely in an internally grooved cylinder.
Also see
Pot life
The rating in hours of the time interval following the addition of accelerator before a chemically curing adhesive or sealer will become too thick to pass viscosity (consistency) requirements. Closely related to working life.
Pot metal
An Alloy that is Cast as a unit. It is relatively inexpensive to make, but is easily subject to breakage.
Potential
An indication of the amount of available energy.
Also see
Potential energy
The mechanical energy possessed by a body due to its position. For example, water in a reservoir above a hydro-electric power station has high potential energy which is converted to work when it drives the Turbines of the power station.
Potentiometer
Instrument for measuring or controlling by sensing small changes in electrical resistance. Also called a rheostat.
See
Pound
See
Pound foot
The unit of measurement for Torque. One pound-foot is equal to the twisting force produced when a one-pound force is applied to the end of a one-foot-long lever.
Pound force
Force applied to a one pound mass; has an acceleration of 32.173 ft/s2.
Pounds Per Square Inch Gauge
(psig) Pressure measured with respect to that of the atmosphere. This is a pressure gauge reading in which the gauge is adjusted to read zero at the surrounding atmospheric pressure. It is commonly called gauge pressure.
Pour point
The lowest temperature at which a liquid (e.g., oil) will pour or flow, a test of its ability to flow and lubricate in cold weather.
Powder
See
Powder coating
See
Powder slush molding
A processing technique applied to produce PVC skins. In a preheated rotating mold, a thin layer of PVC dry blend is evenly spread across the mold surface. The mold is transferred to an oven to fuse the PVC skin and is finally cooled in a water-bath
Power
  1. The rate of doing work. It is expressed in mass times distance over a period of time.
  2. Time rate at which work is done or energy emitted.
  3. The rate of producing, transferring, or using energy, most commonly associated with electricity. Power is measured in watts and often expressed in kilowatts (kW) or megawatts (mW). Also known as real or active power. See Active Power, Apparent Power, Reactive Power, Real Power
  4. To provide power to something, e.g., Power up the radio.
  5. Source or means of supplying energy.
Also see
Power antenna
(PA) or (P.Ant) A radio antenna which automatically moves up and down whenever the radio is turned on or off. It is a telescoping antenna driven by an electric motor.
Also see
Power-assist brakes
A braking system that uses engine intake manifold vacuum (or hydraulic pressure) and atmosphere pressure to reduce the braking effort required at the pedal.
Power assisted
A description of a feature that would normally require a lot of human force, but the engine's hydraulic or vacuum pressure helps to multiply the human effort.
Power assisted brake
See
Power assisted brakes
See
Power-assisted steering
(pas) A steering system in which a hydraulic pump powered by the engine helps the driver to turn the steering wheel. Compare Power steering.
Power-assist Unit
See
Power band
  1. The subjectively defined rpm range over which an engine delivers a substantial fraction of its peak power. The power band usually extends from slightly below the engine's Torque peak to slightly above its power peak.
  2. A certain rpm range in which an engine makes most of its power
Power booster
Power booster

Click image to supersize
Power booster

A device that uses engine Vacuum or hydraulic power to assist you in braking the vehicle. Helps the brake pedal to activate the hydraulic pistons in the Master cylinder
Also see
Power brake
See
Power brakes
(PB) A conventional Hydraulic brake system that uses engine Vacuum to operate a vacuum power Piston, the power piston applies pressure to the Brake pedal, or in some cases, directly to the master cylinder piston. This system reduces the amount of pedal pressure that the Driver must exert to stop the vehicle. Also called "vacuum-assisted brakes" or hydraulic-assisted brakes.
Also see
Power burner
A burner in which either gas or air, or both, are supplied at pressures exceeding the line pressure for gas and atmospheric pressure for air, this added pressure being applied at the burner.
Power chamber
The main housing of a vacuum booster internally partitioned in half by a flexible diaphragm. Pressure differentials between the halves move the diaphragm and create application force.
Also see
Power closing
See
Power conditioning
The subsystem that converts the DC power from the (fuel cell) stack subsystem to DC or ac power that is compatible with system requirements.
Power cut-off
A battery master switch
Power cut-off switch
A battery master switch
Power cycle
See
Power Density
See
Power distribution
A specific drive torque distribution between front and rear axles in a 4WD system.
Also see
Power Efficiency
See
Power element
Sensitive element of a temperature-operated control.
Power Element Control
See
Power Exchange
See
Power factor
  1. Correction coefficient for the changing current and voltage values of AC power.
  2. A measurement of the time-phase difference between the voltage and current in an AC circuit. It is represented by the cosine of the angle of the phase difference. Zero degrees has a power factor of 100%. That means the watts and volt-amperes are equal and there is nothing more than resistance in the circuit. Ninety degrees of angle represents nothing in the way of resistance and only inductance in the circuit. Power factor is also found by the formula: Power Factor = True Power (TP) divided by Apparent Power (AP)
  3. The ratio of the total active power in watts to the total apparent power in volt-amperes (the product of rms voltage and rms current).
Also see
Power Gain
See
Powerglide
(PG) A two-speed Automatic transmission offered by General Motors.
Power hood
British term for Electric top
Power Instability
See
Power loss
The difference between electricity input and output as a result of an energy transfer between two points.
Power Motor
See
Power output
See
Power oversteer
In a rear-wheel-drive vehicle, power Oversteer creates a Skid when too much power is applied and the rear wheels spin.
Powerplant
  1. The automobile engine regardless of its type.
  2. A packaged, self-contained, automatically operated assembly of integrated systems for generating useful electrical energy and recoverable thermal energy.
Also see
Powerpoint
A socket for inserting an auxiliary component. It looks very much like a cigarette lighter socket.
Power seat
(P.seat) The cushions upon which the Driver and or passengers sit which is adjusted by a control switch connected to a small electric motor so that the seat can be moved forward or back, up or down, or be tipped forth and aft.
Also see
Power servo
A vacuum-operated or electrically-powered device that actuates the duct doors and switches on systems equipped with automatic temperature control
Powershift transmission
A transmission which can be shifted without declutching or decelerating
Power split
See
Power steering
(PS) A Steering system using Hydraulic pressure to increase the Driver's turning effort. As the driver turns the Steering wheel, steering effort is reduced. The pressure is used either in the Gearbox itself or in a hydraulic cylinder attached to the Steering linkage. Also called power-assisted or assisted steering.
Also see
Power steering pump
A pump which supplies hydraulic pressure for the power steering system
Power stroke
Power stroke

Power stroke

The third stroke of the Four-stroke cycle. The Piston moves downward from Top dead center to Bottom dead center as a result of the force of Combustion acting on the top of the piston.
Power take off
(PTO)
  1. The end of the crank (usually on the other side from the Magneto or Starter) where the motion of the crank is transferred to the Transmission or power output.
  2. A device (usually a pulley) on an engine or wheel which drives a secondary device. A PTO often drives a hydraulic pump, which can power a dump body, concrete mixer or refuse packer. Some designs mount to a standard opening on the transmission, while others attach at the front or rear of the engine.
  3. An outlet from a vehicle engine used to transfer power to towed equipment or machinery.
Power top
A convertible top which is raised and lowered by a hydraulic system or by electricity.
Also see
Power to weight ratio
See
Power-to-weight ratio
The relationship of a vehicle's Horsepower to the weight of a vehicle. The greater the horsepower is in relation to the weight of the car, the faster the car will go and the faster it will accelerate.
Power train
See
Powertrain
An engine and Transmission combination. Sometimes includes the drive shaft, and drive axle.
Also see
Powertrain control module
(PCME) An electronics module or a computer that receives input from various engine and/or powertrain related sensors to determine the operating condition of the engine and/or other powertrain components at a particular moment. The module or computer responds to these signal inputs by sending signals to various engine controls to meet predetermined operating instructions for basic engine management. A PCME is the only PCM that could include all other PCMs in one unit.
Also see
Powertrain control signals
Signals sent from a powertrain control module to actuators, relays, or solenoids to control the operations of those devices.
Powertrain input signals
Signals from sensors, switches, or solenoids sent to a powertrain control module describing the operational state or condition of those devices at a particular moment.
Power Unit
A truck, or the part of a combination that has the engine.
See
Power valve
An enrichment unit in a Carburetor that is operated by Vacuum or mechanical Linkage to provide more fuel at wide open throttle.
Power window
A side window which is raised and lowered by an electric motor which is operated by a switch. The British term is electric window
Power window lock-out switch
A switch that renders inoperable all electric window controls on the individual windows, except for the master controls on the driver's door
Power windows
Side windows which are raised and lowered by an electric motor which is operated by a switch. The British term is electric windows
Pozidriv screwdriver
A proprietary type of screwdriver whose tip resembles the Phillips cross-head configuration but with four additional wedges, making eight flanks altogether, which allows a more positive drive and a higher torque.

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