Valve Train Calculation Model with Regard to Oil Film Effects

A mathematical equivalent model to describe the dynamic behaviour of mechanical actuated valve trains has been developed which is based on a multi-degrees-of-freedom vibratory system. It could be shown that dampings and stiffnesses efficient in a valve train are influenced by three oil film effects: these are squeeze films between the valve train components, elastohydrodynamic lubrication of cam and follower and the cam shaft bearings.

Thus, the effective values for dampings and stiffnesses within the equivalent model are calculated with regard to these different kinds of oil film effects. The accuracy of the model is demonstrated by a comparison to measured forces and accelerations which were taken up on a pushrod-actuated valve train.