Pushrod Modeling and Valvetrain Dynamics of High Speed IC Engines

A finite element model of the pushrod was derived and integrated into a lumped parameter valve train model. The pushrod model included the nonlinear effects of material dissipation, axial inertia, and coupling of the transverse and axial vibration. Experimental valve motion and pushrod vibration data were obtained, from a valve train test fixture, using proximeters and a strain gauged pushrod. The experimental results were used to identify model parameters and validate the model. Once the effectiveness of the valve train model had been determined it was used to investigate the effect of pushrod bending on the valve train.

The valve train model proved to be very effective in predicting valve train response at high speeds. In addition to this, the pushrod model itself was found to accurately simulate the actual response of the pushrod. However, no distinct relation was found between pushrod vibration and valve response for the system studied.