In order to provide a better user experience, this site uses cookies. Cookies: small text files, that are stored in the memory of your browser or device when you visit a website or open a message. There are different kinds of cookies: Session cookies: Extinguish with the end of the browser session and are valid during a particular browser session. Durable cookies: Are maintained after the browser session Third party cookies: are placed on your device from another site You can disable or remove cookies via the browser settings. Note that in different browsers, the settings are organized differently. Consult the manual. By using you consent to the use of cookies.
Who I am Data Privacy Disclaimer

Automotive glossary: What is a Valve or 4-Stroke Cycle Engine Valve?

Definition of Valve: In contrast to two stroke engines, where the piston controls letting in the gasoline air mixture and letting out the incinerated gas, four stroke engines need valves, which open and close at the proper moment, to control the gas flow. The valves are located in the cylinder head and are opened by the camshaft and (usually) closed again by a spring. Thereby the cams (so bulges) of the revolving camshaft (possibly via rocker levers) push on the backside of the valves, so that the sealing part of the valve is being shifted a bit into the combustion chamber and thereby a gap is opened, through which the gas can flow in resp. out. Accordingly, valves are classified as inlet and outlet valves. Valves are exposed to extremely high thermal and mechanic stress.

All definitions