Dynamic Response of an Overhead Cam Valve Train

This paper presents the dynamic analysis of a complete overhead cam (OHC) type valve train configuration of an internal combustion engine to predict its dynamic response. The valve train model is developed using flexible component approach. Within this approach, each component of the valve train is modeled as an object with the 3D geometry having stiffness, mass, and damping properties. The stiffness properties of the valve train components are calculated using the 3-D finite element model of each component. The dynamic behavior of the valve train is analyzed for the rated speed and over speed of the internal combustion engine to determine the dynamic forces acting in the interface of the valve train components. The results in the form of nodal displacements and valve acceleration are studied to distinguish the occurrence of the jump phenomenon at the rated speed and/or over speed. The model predictions are compared with the experimental observations to insure the validity of the obtained model. Having established the validity of the model, the dynamic forces acting in the interface of the valve train components are estimated which can be used as input for the sustainability analysis of the valve train components at rated and over speeds. The effect of variation in the cam profile on dynamic forces acting on the valve is also studied.