Technique for Experimental Evaluation of Piston Ring—Cylinder Film Thickness

Abstract

A technique for estimating the piston ring film thickness by measuring the ring end gap has been developed. This paper discusses the details of the measurement technique, presents the results of a parametric study of the measured film thickness for unpressurized full-size diesel engine piston rings and compares those results with an analytical model. The film thickness is shown to depend upon the lubricant viscosity, the piston speed, the ring face profile and the quantity of lubricant available to the ring. The results of an analytical model, which assumes flooded lubrication conditions is also presented and the resulting film thicknesses are similar to those measured.