Abstract
Cam/tappet is used under the most severe lubrication condition in a diesel engine. Recent requirements for diesel engines, such as lowering the exhaust gas emission, increase its severity even further. Analyzing its lubrication condition is important for improving cam/tappet durability. Therefore authors developed cam/tappet friction measurement apparatus, and also carried out EHL calculations to clarify its lubrication condition in the past studies. In this study, the lubricants, the important factor of the lubrication are the subjects. The effects of the friction modifier investigated by the authors using the friction measurement apparatus are described.