Abstract: A mixed lubrication model for the piston skirtcylinder liner system is developed to analyze the effects of crankshaft offset on piston dynamics and the lubrication performance of piston skirt. In piston dynamics model the effects of piston ring and connecting rod are considered, while the lubrication model is based on average Reynolds equation, rough surface contact model and Reynolds boundary condition, with consideration of the effect of deformation and the shearthinning effect of lubricating oil on lubrication performance. The effects of crankshaft offset on piston secondary motion and the lubrication performance of piston skirt are analyzed, the potential technical schemes for reducing the friction loss of piston are explored, and the feasibility of technical schemes proposed is verified through prototype trial production and tests. The results show that positive crankshaft offset is an effective measure to reduce the friction of piston skirt and the fuel consumption of engine.

Key words: engine, crankshaft offset, piston skirt, mixed lubrication, low friction, engine, crankshaft offset, piston skirt, mixed lubrication, low friction