Scuffing initiation caused by local starvation in a piston ring cylinder liner contact

Abstract

Scuffing is a localized damage process caused by a sudden failure of the lu- bricating film in a sliding contact. It is associated with an important increase in temperature, friction and vibration. For the piston-ring cylinder-liner (PRCL) contact, it can lead to a complete engine failure. It is shown in this paper, that the temperature gradient generated in the contact induces the thermal Marangoni effect. The latter might then lead to a localized lack of lubricant that can initiate scuffing. On the contrary, the ring displacement along the liner redistributes the oil on the surface. This redistribution helps to avoid starvation hence reducing scuffing initiation risk. Based on the competition occurring between these two effects, a computational model was developed that predicts scuffing appearance in internal combustion engines. The origi- nality of this paper lies in presenting the complementary contribution of the Marangoni phenomenon to the scuffing initiation in the PRCL contact.