Elastohydrodynamic lubrication of piston rings

Abstract

A non-linear finite-element scheme, based on the Newton-Raphson-Murty algorithm, was used to analyze the problems of piston rings according to theories of both elastohydrodynamic and hydrodynamic lubrication. The maximum film pressure and the minimum film thickness were obtained and depicted as functions of the crank angle. For hydrodynamic lubrication the results obtained were compared with those found using the method suggested by Dowson and Ruddy; there was good consistency between them. In this way the accuracy and reliability of the proposed method are demonstrated. Furthermore, the results evaluated using the theory of elastohydrodynamic lubrication give a larger minimum oil film thickness and a flatter pressure distribution than those evaluated using the theory of hydrodynamic lubrication.