Thermoelastohydrodynamics of a rough piston compression ring-to-cylinder bore conjunction

A thermo-elastohydrodynamic analysis of piston compression ring conjunction is presented. Regime of lubrication alters with contact load and piston kinematics. These affect the parasitic losses, improve fuel efficiency and emissions. These are significant, particularly in high performance engines. Lubricant film thickness determines the mechanisms of friction; viscous shear and boundary friction. The friction generated heat reduces the effective lubricant viscosity. Salient features include in-situ ring geometry within an out-of-round bore and ring in-plane modal behaviour. The results show thin films, promoting some asperity interactions. The analysis is a guide for surface modification (coating and/or textured features) to improve lubrication.