Experimental research on the frictional performance of real laser-textured cylinder liner under different lubrication conditions

Abstract

Laser surface texturing technology including the steps of surface pre-processing, laser texturing, and surface post-polishing was utilized to process typical micro-dimples(diameter 50 μm, depth 8 μm, and area ratio 10%) on the cylinder liner surface in a production engine. By conducting the reciprocating friction tests on a friction-wear tester, the instantaneous friction force of the real cylinder liner-piston ring pair was measured for comparing the tribological performance of plateau-honed cylinder liner and laser-textured cylinder liner. The testing results showed that under different lubrication conditions, laser texturing cylinder liner could effectively reduce the friction force, especially the peak force around the reciprocating stroke ends of ring/liner pair. Within a reciprocating stroke, the average friction coefficients of the laser-textured cylinder liner-piston ring pair decrease by approximately 18.6%–37.6% under low temperature oil bath condition dominated by hydrodynamic lubrication, while the friction coefficients decrease by approximately 1.8%–6.1% under high temperature oil bath condition dominated by mixed lubrication compared with these of the plateau-honed cylinder liner-piston ring pair. This indicates that laser texturing cylinder liner with appropriate micro structures could enhance the hydrodynamic effects and reduce the friction of ring/liner system, which is conducive to improving the engine mechanical efficiency and the application of low-friction design on production engine.