Automotive Terms - P

Pick-up

The type of truck with an open cargo bed behind the closed cab.

Pinion

A type of gear that has small teeth that mesh with other, larger gears.

Piston

The heavy, cylindrical metal shaft within each engine cylinder that travels up and down to turn the crankshaft, compress the air and fuel mixture for combustion and expel exhaust gases.

Power Steering

A steering system that uses a separate motor or engine power to reduce the effort necessary to turn the front wheels.

Power-to-Weight Ratio

The maximum power output of the vehicle per unit mass. The higher the ratio, the more powerful the vehicle. In comparing several vehicles, this can be a better measurement than engine horsepower or torque because it considers the weight variable. In other words, a car that seems to have a powerful engine but is also heavy may have less get-up-and-go than a vehicle that has a similar or less powerful engine but also weighs less.

Powertrain

The combination of engine and transmission.

Power Plant

Another name for a vehicle's engine.

Projector-Beam Headlights

A headlight that uses a spherical reflector to tightly control the light beam. The bulb or light source directs the light inward, toward the reflector at the back of the headlight assembly, which then projects it forward from the vehicle. These lights are more powerful, accurate and expensive than standard sealed-beam and halogen headlights, and are generally found on sport and luxury models.

Pushrod

A metal rod that transmits the motion of the camshaft.