A dynamic deformation based lubrication model between the piston rings and cylinder liner

The piston ring-cylinder liner friction pair is one of the most important friction pair in IC engines. In previous modelling studies, most researches were carried out based on a hypothesis that the inner surface of liner is an ideal cylindrical shell without considering the effects of dynamic deformation on oil film distribution. To investigate the potential influences of structural deformations on tribological behaviors of cylinder assemblies, the dynamic deformation of liner surface was obtained by FEM-based dynamic simulation, and then introduced into the lubrication model. Different from the traditional lubrication model where the pressure stress factor and shear stress factor are regarded as constant, this paper calculated these factors in real time by numerical integration to achieve more realistic simulation results. This study shows that the friction force obtained from the improved model manifests obvious fluctuations, and shows a significant reduction compared to original model.