Influence of Cam Surface Finish and Roughness on Frictional Power Loss in Valve Trains With Roller Tappets

In order to reduce the frictional power loss and the wear in the valve train of internal combustion engines, the cam follower mechanism tends to be shifted from the sliding contact to the rolling contact such as a roller follower [1–5]. Design criteria for the valve train with roller tappets have been investigated by making obvious the effect of the cam lobe surface finish and its surface roughness on reduction of the friction loss. In particular the friction loss in the case of a cam lobe finished by shot-peening was compared with that of one finished by grinding. Also the influence of surface roughness on the friction loss was examined.