Soupape d'échappement (moteur)

A valve is a component that controls the flow of a fluid or gas by opening, closing, or directing a passage.

It starts, stops, or regulates flow and can hold pressure or allow flow in one direction only, depending on its design.

Valves are used in the engine, fuel, cooling, and air/brake systems. The correct valve matches the system, the flow and pressure it handles, and its connections.