Tribological Study of Friction in Roller Follower Valve Train Considering Effects of Asperity Interaction and Roller Sliding

Abstract

The performance and durability of components in engine valve train is largely governed by the friction. The valve train is often subjected to severe and transient operating conditions promoting friction, greatly. The aim of this work is to develop a comprehensive numerical approach to analyze the friction in roller follower valve train considering the effects of roller sliding, friction due to asperity interaction and friction arising from other components under different operating conditions. Simulation results predicted that the friction from asperity interaction becomes dominant at higher oil supply temperature. High magnitude of sliding friction was observed due to the rise in roller sliding by increasing the camshaft rotational frequency and lowering the lubricant oil supply temperature. The numerical approach developed in this paper is validated by already available experimental data in the form of drive torque and good conformity between the magnitude of measured and predicted results was observed.