The Influence of Variable Ring Face Profile and Bore Shape on Piston Ring Behaviour in Internal Combustion Engines

This paper examines the influences of a non-circular bore and circumferential variations in face profile on piston ring performance. It is shown that both circumferential variation of ring face profile and bore shape significantly influence operating oil film thickness, ring friction and oil transport during the engine cycle. Experimental measurements of ring film thickness in an engine simulator show encouraging agreement with predictions of the model.