The collection of parts that make the valves operate in an internal combustion engine. The valvetrain includes the camshafts and all related drive components, the various parts that convert the camshafts rotary motion into reciprocating motion at the valves, and the valves and their associated parts.
CAD model of the valvetrain of a 4 cylinder in-line engine. Number 1 and 4 pistons are at TDC.
This is a twin overhead cam, four valves per cylinder engine.
A valve train system in an automotive engine is designed to meet three main functional requirements:
- Maximize the valve life area during gas exchange into or out of combustion chamber during specified period.
- Achieve the reliable operation up to the maximum anticipated engine speed, subject to durability consideration.
- Minimize engine power loss to friction.