A New Approach for the Analysis of OHC Engine Cam Shape

An overhead camshaft valve train system with center pivot rocker has been analyzed. Considering the valve train as a rigid body and using the concepts of differential geometry and coordinate transformation, we can find the mathematical formulas of sufficient and necessary conditions to generate a cam profile.

A valve train dynamic test rig was set up to investigate the relationship between valve motion and cam profile. The valve dynamic characteristics were also studied. Valve lift was measured by a LVDT, and valve train dynamic stress was monitored by a strain gage mounted on the rocker arm. Valve noise was measured by a microphone located near the valve seat. And, the relationship between valve noise and cam profile has been investigated.