A Numerical Analysis of the Nonsteady EHL Process in High-Speed Rotating Engine Cam/Tappet Pairs

In this paper, by accounting for the effect of dynamic behavior in valve train mechanisms on the surface contact load of a cam/tappet pair, a full numerical solution of nonsteady EHL for a high-speed diesel engine cam/tappet pair is obtained by a fast solution scheme. The shape of the lubricant film and the characteristics of pressure distribution on cam/tappet pair surfaces are further studied. The lubrication process of a cam/tappet pair at the opening and closing sides and in the most dangerous zone in normal working conditions is also analyzed. This analysis provides the theoretical basis which best approximates practical working conditions for designing cam profiles and establishing reasonable running-in condition.