Influence of different loads and temperatures on solid lubricant-filled micro-dimples existing on both cylinder liner and piston ring

Abstract

In order to meet the increasing demands of friction reduction and wear resistance in heavy-duty diesel engines, the refined design of surface topography of cylinder liner and piston ring (CLPR) has been a major concern. Based on electrolytic micro-texturing and electrochemical deposition methods, micro-dimples filled with solid lubricant have been separately applied to the CLPR surfaces. This double-sided textured design of CLPR exhibited significantly lower friction coefficient and wear depth than the non-dimpled CLPR when the lubricating oil containing zinc dialkyldithiophosphates (ZDDP) was used under different strengthening loads and temperatures. Solid lubricants were released from the double-sided textures, forming mutually transferable solid lubricant films on the sliding surface. Although various products containing molybdenum oxides, molybdenum sulfides, phosphate of different chain lengths, zinc compounds, iron sulfide, etc. Appeared in the tribochemical reactions of ZDDP and MoS2 with increasing temperature and load, but the lubricating effect was still maintained. These results can provide some insight into the design of CLPR surfaces in order to achieve a high quality tribofilm under heavy load conditions.