The effect of laser machined pockets on the lubrication of piston ring prototypes

Surface texturing has emerged as a promising method to reduce friction loss at the piston ring/cylinder liner contact. The objective of this study is to investigate the potential for a new design of lasered oil pockets to improve the lubrication of piston rings. These pockets are fabricated at the inlet and outlet of a piston ring and can work as tiny step bearings to generate hydrodynamic lift. A series of bench tests are conducted to investigate the frictional performance of flat piston ring prototype (PRP) with various pockets. The results show that the pocket area ratio (AR) and depth have a major influence on the tribological behavior and significant friction reduction can be achieved by using pockets with appropriate geometric parameters (AR=25%, depth=5 μm). In addition, a preliminary theoretical model that implements the mass-conservative cavitation algorithm was used to analyze the influence of pocket geometric parameters on the PRP lubrication. The simulation results showed good agreement with the trends observed in the experiments.