Simulation of Cam Wear in Valve Trains of Diesel Engines

In order to predict cam wear in valve trains of engines quantitatively, multi-body system dynamic analysis, finite element quasi-statics contact analysis and numerical calculation of elastohydrodynamic lubrication are applied to obtain the dynamic loads, the time histories of contact pressure and the oil film thicknesses in a cam-tappet pair. Using this methodology, the wear depth of the cam in the valve train of a heavy load diesel engine is calculated, which is in good agreement with the measured value in the practical tests. The results show that the cam-tappet is operated in a mixed lubricant or a boundary lubricant regime and the wear depths on both the sides of the cam have been found to be the greatest.