Assessing lubricating film thickness between compression rings and engine cylinders: A comprehensive comparison of theoretical predictions and experimental measurements

Abstract

The purpose of piston rings in combustion engines is to provide an effective seal between the combustion chamber and the crankcase while allowing rapid linear movement of the piston. In this paper a review of around 50 experimental studies and 30 theoretical studies is presented. Papers describing experimental studies report lubricating film thicknesses between 0 µm to 20 µm, while papers describing theoretical results for fully flooded analyses tend to report smaller values (0 µm to 9 µm). Theoretical studies including starvation phenomena normally give even thinner films, typically between 0 µm and 5 µm. The paper presents a discussion of these discrepancies.