Monday, 17 February 2020, 6:24 PM
Site: IMI eLearning
Course: IMI eLearning (IMI eLearning)
Glossary: Automotive Glossary
P

Particle Size

The size of the pigment particles in a dispersion (e.g. paint).

Particulates

Exhaust pollution consisting of very small particles of matter (soot) that are produced as a by-product of combustion. Seen as smoke in a vehicle exhaust, particularly from diesel engines.

PAS

Power Assisted Steering.

Pascal (Pa)

Standard unit of pressure (N/m2) named after a scientist who studied pressure in liquids. Pascal's principle of the transmission of pressure in fluids established that the pressure in a completely filled container is equally applied throughout and any change in pressure is transferred to all parts of the fluid and walls of the container.

Passivation

The conversion of a metal surface to a less reactive state. A process used by vehicle body manufacturers to reduce the corrosion rate of a metal surface, particularly low-carbon steel.

Passive Restraint

Safety features of a vehicle that act only in an accident. Seat belts, head restraints, air bags and pre-tensioners are examples.

Password

Personal Identification, used in conjunction with a Smart Card to access the MOT database via the VTS device. Can be numbers or letters, or a combination of both.

Pawl

Part of the ratchet mechanism that holds the ratchet. A pivoted tooth that engages in the teeth of the ratchet wheel to either prevent the pawl lever or the wheel from rotating in one direction only or in some mechanisms to drive the wheel forward.

PCM

Powertrain Control Module.

PCV

Positive Crankcase Ventilation. A series of pipes and valves connecting the engine crankcase to the inlet manifold or air cleaner in order to reduce oil vapour emission to atmosphere.