Insight into friction and lubrication performances of surface-textured cylinder liners and piston rings

Abstract

The effects of surface-texture technology on the friction and lubrication mechanism of cylinder liner-piston rings (CLPR) were explored in this study. An inclined groove texture was machined on the CL of a S195 diesel engine and dimples designed on the gas ring. Friction and wear tests of nontextured (NT), CL textured (CLT), and PR textured (PRT) conditions were performed on a CLTR friction and wear tester under different temperatures. First, the characteristics of friction and lubrication at different temperatures were analyzed by examining friction and contact resistance. Then, the wear characteristics were analyzed by examining surface morphology parameters of the CL and the PR wear mass after testing. Finally, the friction and lubrication mechanisms of NT, CLT, and PRT were studied by analyses of real-time friction and contact resistance in one cycle. The results showed that, under the same temperature, CLT and PRT increased oil film thickness, improved the lubrication state, and reduced friction, with CLT better than PRT in these respects. With increased temperature, the wear degree of CL liners became larger. The existence of surface texture reduced CL wear, yielded CL surface morphology not excessively changed by temperature, and improved its supporting performance and oil storage capacity. The inlet suction effect, structural effect, micro-wedge action, balancing wedge action, squeezing effect, and cavitation effect should be taken into account together when exploring the mechanism of the influence of surface texture on friction pairs. This study provided a method for scholars to explore the friction and lubrication mechanism of different texture types and provided an experimental basis for improving the performance of CLPR friction pairs.