Prediction of total engine friction power loss from detailed component models

This paper presents an analytical approach to estimate the total engine friction power loss from the detailed tribological analysis of major components such as piston assembly, cam/tappet interfaces and bearings. For the piston assembly (rings and skirt), it uses the starved and mixed lubrication model, coded as RPM99. For cam/tappet interfaces, it uses the CTM99, an in-house developed code that considers the surface roughness and EHL effects. For the bearings, including mains, big ends and camshaft, it uses the mobility method. The advantages of the above approach include: (a) the reflection of major component design details in the model, and (b) the consideration of lubricant properties at specific engine operating conditions.