Piston Ring Friction Reduction Through Surface Modification

A numerical model has been developed to investigate the effects of surface modifications on the lubrication condition and frictional loss at the interface between a piston ring and cylinder liner. The effects of boundary and mixed lubrication conditions were included through the use of a fully deterministic mixed lubrication model, which provides detailed information of the rough contact zone throughout the stroke. The effects of non-Gaussian surface characteristics (e.g. skewness) on the cycle-average frictional performance are discussed. Surface modifications in the form of circular profile dimples were added to the cylinder liner and their effects were investigated. The modified cylinder liner was shown to reduce the cycle-average coefficient of friction by 55–65%, while total energy loss per cycle was reduced by 20–40%.