Dictionary of Automotive Terms Abbreviations

DICTIONARY OF AUTOMOTIVE TERMS - "Pl"

PL: Acronym for parking lock

PL&PD: Acronym for Public Liability and Property Damage as a form of basic car insurance

Place in service: A vehicle is placed in service if that vehicle is new to the fleet and has not previously been in service for the fleet. These vehicles can be acquired as additional vehicles (increases the size of the company fleet), or as replacement vehicles to replace vehicles that are being retired from service (does not increase the size of the company fleet).

Plain bearing: A cylindrical sleeve friction bearing; most commonly used type of bearing.

Also See
ball bearing
needle bearing
roller bearing

Plain disc wheel: A type of wheel without holes or slots in the wheel disc

Plain gage tubing: See
plain gauge tubing.

Plain gauge tubing: Tubing whose thickness remains constant over its entire length.

Plain wrapper: Trucker slang for Unmarked police car as in "Plain wrapper sitting at the 57 taking pictures."

Plan: See
body plan
capacity plan
lines, plan

Planar cells: See
flat plate cells.

Plane: A flat surface. See inclined plane.

Plane sailing: A method of navigation which ignores the earth's curvature, treating its surface as a plane. Colloquially it indicates travel or procedure without difficulty or obstruction.

Planetary albedo: The fraction of incident solar radiation that is reflected by the Earth-atmosphere system and returned to space, mostly by backscatter from clouds in the atmosphere.

Planetary gear: A gear used in some starters as an intermediate transmission

Planetary gear differential: A planetary gear set used as a differential with asymmetric torque distribution, as used in 4WD vehicles

Planetary gears: See
planetary gearset.

Planetary gearset

A gearing unit consisting of a ring gear with internal teeth, a sun or central pinion gear with external teeth, and a series of planet gears that mesh with both the ring and the sun gear. Frequently used in overdrives and automatic transmission. Also called epicyclic gearbox.
A central externally toothed sun gear, an internally toothed outer ring gear, and several intermediate planet gears which are evenly spaced and supported by a planet carrier; they are in constant mesh with the sun gear and the internal gear

Also See
ravigneaux planetary gear set
simpson planetary gear set

Planetary gear set: See
Planetary Gearset

Planetary-gear system: A gearset used in automatic transmissions that features a central gear, called a sun gear, surrounded by two or more smaller planetary gears that mesh with a ring gear.

Planetary set: See
ravigneaux planetary gear set

Planetary transmission: A form of gear used by Benz in which small pinions revolve around a central or sun gear and mesh with an outer ring gear called the annulus. Type used in the Ford Model T. Also called epicyclic gearbox and "sun-and-planet gears."

Planet carrier: That part of a planetary gearset upon which the planet gears are affixed. The planet gears are free to turn on hardened pins set into the carrier. The planet carrier revolves around the central axis of a planetary gear set and supports the planet gears

Planet gear: See
planet gears
stepped planet gear
sun and planet gears

Planet gears: Those gears in a planetary gearset that are in mesh with both the ring and the sun gear. They are referred to as planet gears in that they orbit or move around the central or sun gear.

Also See
stepped planet gear
sun and planet gears

Planet pinion: See
planet gear

Planets: See
twin planets

Planet spider: A common type of planet carrier with a spider or web-style design

Planet wheel: See
planet gear

Planishing: The final panel hammering stage for lifting out minor imperfections in a panel surface. Part of the panel finishing process

Planishing hammer: A panel beater's hammer

Planck's constant: Constant value (6.626 x 10^-34 watt seconds squared) which, when multiplied by the frequency of radiation, determines the amount of energy in a photon.

Plan lines: The plans that show the shape or form of the ship

Planned obsolescence: A policy of manufacturers that encourages motorists to become dissatisfied with their cars so that they are eager to buy the latest model.

Planning: See
product planning

Plant: See
pressing plant

Plant condensate: One of the natural gas liquids, mostly pentanes and heavier hydrocarbons, recovered and separated as liquids at gas inlet separators or scrubbers in processing plants.

Plant products: Natural gas liquids recovered from natural gas processing plants (and in some cases from field facilities), including ethane, propane, butane, butane-propane mixtures, natural gasoline, plant condensate, and lease condensate.

Plaque: See
dashboard plaque

Plasma: Temporary physical condition of a gas after it has been exposed to and has reacted to an electric arc.

Plasma arc cutters: Cutting equipment that makes clean, fast cuts without destroying the properties of high-strength steels

Plasma spray process: The process in which a very high temperature flame is produced by blowing gas through an electric arc. Metal wire or powder is melted by passage through the flame and is projected on the surface to be coated

Plastic: A material that contains as an essential ingredient one or more organic polymeric substances of large molecular weight. It is solid in its finished state and, at some stage in its manufacture or processing into finished articles, can be shaped by flow.

Also See
glass reinforced plastic
hydrocarbon plastics

Plastic deformation: A permanent change in the shape or size of a solid body without fracture resulting from the application of sustained stress beyond the elastic limit

Plastic engine: An automobile engine whose bulk is made of plastic components (e.g., engine block, inlet manifold, water-pump housing, valve covers, oil pan), the use of metal being limited to parts subjected to extreme mechanical or thermal loads (e.g., combustion chamber, exhaust manifold, pistons, cylinder liners, valve train, etc.)

Plastic filler: See
polyester filler

Plasticize

To soften a material to make it plastic or moldable by heating, kneading, or adding a plasticizer
To soften an adhesive, coating or sealer, generally by the addition of high boiling liquids or plasticizers

Plasticizer

An additive that gives flexibility to an otherwise rigid plastic
A liquid or solid chemical added to a compound to impart softness or flexibility. Some plasticizers have an undesirable tendency to migrate from the parent material into nearby surfaces which are receptive. When they migrate into adhesive films, for instance, they generally cause loss of strength or complete failure of the bond

Plastic molding: A process that converts organic-based materials, by means of a general-purpose press and purpose-built tooling under controlled heat and pressure, and injects the hot material into a die cavity shaped in the final form of the intended part.

Plastics welding: A uniting of thermoplastic, i.e., non-setting plastics of similar or different type using heat and pressure and with or without the addition of plastic of a similar kind (filler material). The welding proceeds within the temperature range of thermoplasticity of the contact surfaces on the parts to be welded; the freely mobile molecular chains in the marginal areas flow together and become interlaced

Plastigage: A soft plastic that flattens out to predetermined widths when subjected to torque; these widths equal a specific clearance. It is normally used to check main and rod-bearing clearance. It is sold in a paper sleeve that also doubles as the scale on which it is measured (in thousandths of an inch)

Plastigauge: A plastic material that compresses to the thickness of the clearance between a crankshaft journal and a bearing when the bearng retaining cap is installed, so the clearance can be checked against specifications

Plate

The action of coating a material with some metal. Also called electroplate" or anodize.
A flat piece of material.
Two lead-alloy plates in each cell where the positive plate is made of lead peroxide and the negative plate is made of spongy lead. Separators are placed between the plates of different polarity.
The electrode, in a valve or tube, held at a positive potential with respect to a cathode, and through which positive current generally enters the vacuum or plasma, through collection of electrons.
Clutch discs

Also See
adapter plate
backing plate
baffle plate
blanking plate
brake backing plate
breaker plate
center drive plate
chafing plate
clutch plate
clutch pressure plate
contact breaker plate
driven plate
drive plate
end cover plate
flitch plate
friction plate
governor plate
gusset plate
heel plate
hinge plate
hinge tapping plate
hub plate
intel-plate
intermediate drive plate
intermediate plate
keel, flat plate
license plate frame
license plate
nave plate
negative plate
positive plate
pressure plate
rear license plate lamp
rear license plate light
registration plate
restrictor plate
retainer plate
scuff plate
sensor plate
skid plate
spacer plate
step plate
stopper plate
striker plate
swash plate
tapping plate
thrust plate
torque converter drive plate
transfer plate
valve body separator plate
valve plate
vanity plate
wobble plate

Plated: See
armor-plated
cadmium-plated
chrome-plated
chromium-plated

Plate frame: See
license plate frame

Plate grid: See
grid

Plate group: An assembly of plates of identical polarity (positive or negative) used in a battery cell

Plate keel: See
flat plate keel

Plate lamp: See
rear license plate lamp

Plate light: See
rear license plate light

Plates

Thin sections of lead peroxide or porous lead in a battery. There are two kinds of plates -- positive and negative. The plates are arranged in groups, in an alternate fashion, called "elements," they are completely submerged in the electrolyte.
Any basically flat surface often used to mount another device.

Also See
baffle plate
brake backing plate
breaker plate
clutch pressure plate

Plate strap: The conducting connection between the lugs of battery plates of like polarity and the cell terminal

Plate support: The support at the bottom of a battery case on which the elements rest. It provides space for the sediment chamber

Platform: Primary load-bearing structural assembly of a motor vehicle determining the basic size of the motor vehicle, and is the structural base that supports the driveline and links the suspension components of the motor vehicle. Also see lifting platform take-up point

Platform frame: The underbody construction consisting of a reinforced and fairly flat section that forms the entire lower portion of a vehicle. It includes the floorpans and is bolted to the body; (e.g., Volkswagen Beetle)

Platform pedal: Older style pedal that the foot rests on top of and is not locked into.

Platform take-up point: See
lifting platform take-up point

Plating: The coating of metal usually by electrolysis.

Also See
black chromium plating
chromium plating
copper plating
gold plating
hard chromium plating
mechanical plating
nickel plating
shell plating
silver-plating
zinc plating

Platinum: A precious light-grey, heavy, ductile, noble metal, atomic number 78, atomic weight 195.09; melting point at 1769°C. It is the main member of the so-called platinum metals. Together with other platinum metals, it is used as a catalyst in automotive exhaust converters. It is used in the construction of breaker points. It conducts electricity well and is highly resistant to burning.

Platinum electrode: A spark plug electrode made of platinum which lasts longer than one of nickel alloy because it can better withstand high temperatures

Platinum metals: A generic term for a family of noble metals found with and resembling platinum. It includes ruthenium, rhodium, palladium, osmium, iridium, and platinum. They are used as catalysts in catalytic converters. Less than a tenth of a troy ounce is required per converter to produce acres of catalytically active catalyst surface

Platinum spark plug: A spark plug with a platinum center electrode

Platinum-tipped spark plugs: Most General Motors vehicles built since 1995 are equipped with platinum-tipped spark plugs. Under normal operating condition, platinum-tipped spark plugs are designed to function up to 166,000 km. They are designed to operated with a wider gap. The electrode is platinum-tipped and the body is stainless steel.

Play: Movement between two parts.

Also See
camshaft end play
end play
free pedal play
free play
pedal free play
radial play

Player: See
cassette player
CD player

Plenum

A chamber, located between the throttle body and the runners of an intake manifold, used to distribute the intake charge evenly and to enhance engine breathing.
An enclosure containing air or gas at a higher pressure than exists outside.
The air ducts, air valves and blower assembly inside the dash
Also see intake plenum

Plenum chamber

A large cast alloy body in an induction system which connects the throttle body or inlet tube to the cylinder head(s) or inlet manifold.
The air compartment in a car body formed between the scuttle and the bulkhead, providing a basis for the interior air supply
Chamber or container for moving air or other gas under a slight positive pressure.

Plexiglas: A trade name for an acrylic plastic, made by the Rhom and Haas Co.

Plexiglass: See
plexiglas.

Pliers: A gripping tool with two hinged arms and serrated jaws.

Also See
action locking pliers
angle-nose pliers
bending pliers
circlip pliers
clamp pliers
clip pliers
combination pliers
crimping pliers
end cutting pliers
eyelet pliers
flat-nosed pliers
flat-nose pliers
general purpose pliers
half-moon slip joint pliers
heavy-duty diagonal cutting pliers
heavy-duty end cutting pliers
high leverage diagonal cutting pliers
high leverage end cutting pliers
hose clamp pliers
hose clip pliers
hose pinch-off pliers
internal circlip pliers
locking pliers
lock ring pliers
long-nose pliers
long-nose self-grip pliers
multigrip pliers
needle-nose pliers
parallel action locking pliers
piston ring pliers
radiator hose shark tooth pliers
shim pliers
snipe-nose pliers
spark plug pliers
thin needle-nose pliers
valve shim pliers
valve stem seal pliers

Plies: See
ply
stabilizing plies
tire plies

PLL circuitry: A phase-locked loop circuitry in a radio which "locks" the station frequencies to ensure utmost frequency stability

Plug

A removable "cork" or stopper which fills a hole.
A spark plug.
A male electrical connector.
To seal with a stopper

Also See
blanking plug
coil glow plug
cold plug
core hole plug
core plugs
drain plug
drain plug key
drain plug spanner
drain plug wrench
expansion plug
fill plug
flame glow plug
freeze plug
glow plug
glow plug indicator
glow plug starter switch
heater plug
hot plug
hot spark plug
level plug
magnetic drain plug
magnetic plug
oil drain plug
oil pan drain plug
open coil glow plug
open element glow plug
pencil-type glow plug
platinum spark plug
radiator drain plug
resistor spark plug
RFI suppressed spark plugs rubber plug
self-regulating sheathed-type glow plug
sheathed-type glow plug
sooted plug
sooty plug
spark plug
spiral-type glow plug
split electrode spark plug
SR sheathed glow plug
sump drain plug
sump plug
surface discharge plug
surface gap spark plug
welch plug
wire glow plug

Plug body: See
spark plug body

Plug boot: See
spark plug boot

Plug boot puller: See
spark plug boot puller

Plug brush: See
spark plug brush

Plug cable: See
spark plug cable

Plug cable cover strip: See
spark plug cable cover strip

Plug cable loom: See
spark plug cable loom

Plug cable marker: See
spark plug cable marker

Plug cable separator: See
spark plug cable separator

Plug caddy: A special box which can hold spare spark plugs and is especially used by snowmobilers.

Plug cap: The device on the end of the high tension wire coming from the coil and mounted on the spark plug. Also called spark plug cap

Plug condition: See
spark plug condition

Plug electrode: See
spark plug electrode

Plug gap: See
spark plug gap.

Plug gapping: Adjusting the side electrode on a spark plug to provide the proper air gap between it and the center electrode.

Plug gauge: See
spark plug gauge

Plug ignition: See
twin plug ignition

Plug-in diagnosis: On-board computer provides means for special test equipment to be plugged in for making a series of programmed tests to check condition of various units and systems on the vehicle

Plug indicator: See
glow plug indicator

Plug insert tap: See
spark plug insert tap

Plug insulator: See
spark plug insulator

Plughole: The hole in a tank or cistern, which can be closed with a rubber plug

Plug key: See
drain plug key

Plug lead: See
spark plug lead

Plug patch: A tire repair material which is forced into a nail hole to fill it. The plug is attached at one end to a patch that seals the hole and then expands to fill the hole. Although a common procedure, it is not the most satisfactory method of repair

Plug pliers: See
spark plug pliers

Plug repair: The filling of a nail hole by forcing repair material into the damaged area, often while the tire is mounted and containing air. It is not a satisfactory method of repair.

Plug reversal: The reconnecting of an electric motor's windings to reverse its direction of rotation while running

Plug shell: See
spark plug shell

Plug socket: See
spark plug socket

Plug spanner: See
drain plug spanner
spark plug spanner

Plug starter switch: See
glow plug starter switch

Plug tester: See
spark plug tester

Plug weld: A weld which holds two pieces of metal together and made in a hole in one of metal which is lapped over the other pieces. Also called "rosette weld."

Plug welding: A number of holes are punched along the edge of the repair section to be welded in; the section overlaps the damaged area to be repaired and is welded to the base metal at the punched boles. This is a convenient way of duplicating the spot welding process used by manufacturers, as spot welding equipment is usually too expensive and cumbersome for repair purposes

Plug whiskering: See
gap bridging
spark plug whiskering

Plug wire: See
spark plug wire

Plug wire cover strip: See
spark plug wire cover strip

Plug wire loom: See
spark plug wire loom

Plug wire marker: See
spark plug wire marker

Plug wire separator: See
spark plug wire separator

Plug wrench: See
drain plug wrench
spark plug wrench

Plunger

Any immersing type of piston.
A hydraulic tappet component (e.g., in a valve).
An actuating element in an ignition lock.
A piston in a starter solenoid. Also see control plunger

Plunger principle: A new ABS control system which offers improved pressure modulation with very small amplitudes even at pressures close to zero. Compare valve principle

Plunger pump: An oil pump consisting of a reciprocating plunger in a ported chamber

Plunger suspension: A suspension system in which the vertical movement of the axle is controlled by springs mounted above and below the axle.

Plunging joint: A slip joint which is a connection in the drive train, of variable length, which permits the drive shaft to change in effective length. The British term is "sliding joint"

Ply: A layer of rubber-coated parallel cords which forms a unit of a tire carcass. The plies are made of cord, fiberglass, steel, or structural fabric.

Also See
bias tire
conventional cross ply
radial ply
tire plies
tire ply

Plymouth: A vehicle brand of which the Fury for 1956-58 are milestone cars. The Satellite SS and GTX for 1965-70 are milestone cars. The Barracuda Formula S for 1965-69 are milestone cars. The Roadrunner and Superbird for 1968-70 are milestone cars.

Click image for books on Plymouth

Ply rating: (PR) An indication of tire strength and load carrying capacity. It does not necessarily indicate actual number of plies. A two-ply four-ply rating tire would have the load capacity of a four-ply tire of the same size but would have only two actual plies. This system of measurement has been replaced by the term load range."

Ply separation: A breakdown of the bonding compounds resulting in the plies detaching from each other. Usually as a result of excessive heat.

Ply tire: See
bias ply tire

Ply turnup: The extension of a carcass ply to its end after wrapping around the bead. Also called "flipper strip"