Modeling and prediction of the running-in behavior of the piston ring pack system based on the stochastic surface roughness

This paper proposes an efficient numerical approach to predict the initial running-in process of piston ring pack/cylinder liner system. A combined mixed lubrication and wear model coupled with an oil transport model was developed. In order to predict the hydrodynamic pressure efficiently, two improved methodologies, including the Fischer-Burmsister-Newton-Schur (FBNS) approach and the Grid Refinement (GR) strategy, were adopted. Meanwhile, in order to take into account the effect of skewness, Weibull distribution function was adopted to characterize the asperity height distribution. Predicting the wear of cylinder liner was based on the Archard's wear law. The influences of asperity plastic deformation and wear on asperity height distribution were considered. The results show that the developed model can well predict the initial running-in behavior of piston ring pack/cylinder liner system under an engine-like condition.