Friday, 23 April 2021, 6:07 PM
Site: IMI eLearning
Course: IMI eLearning (IMI eLearning)
Glossary: Automotive Glossary
V

Value

The degree of darkness or lightness of a colour.

Valve

A control device that restricts or cuts off the flow of a liquid or gas.

Valve Ball

A ball used to create a seal inside a valve.

Valve Block

Collection of valves in one unit that operate a common system (automatic transmission for example).

Valve Bounce

Bounce of a valve in its seat when closing. Usually occurs as a result of the engine speed being too high or the valve spring losing tension through age or deterioration.

Valve Gear (Train)

The mechanism from a cam to a valve in an engine that transmits the movement of the cam to open the valve.

Valve Guide

The tube or sleeve in the cylinder head that locates a valve centrally in its seat. The valve slides in the guide during opening and closing.

Valve Head

The top or disc end of a valve that seals the gases in the cylinder head.

Valve Lag

The term applied to valves which remain open after the piston has passed tdc or bdc at the end of a stroke in the four stroke cycle.

Valve Lead

The term applied to valves which open before the piston has passed tdc or bdc at the beginning of a stroke in the four stroke cycle.