Adaptability of piston skirt coatings on the tribological performance of heavy-duty diesel engine under low viscosity lubricant

Abstract

Purpose The purpose of this paper was to improve the frictional wear resistance properties of piston skirts caused by the low viscosity lubricant by studying the tribological performance of three novel coating materials. Design/methodology/approach Comparative tribological examinations were performed in a tribological tester using the ring-block arrangement under two viscosity lubricants, the loading force was applied as 100 N, the speed was set to 60 r/min and the testing time was 180 min. Findings Under low viscosity lubricant, the friction coefficient and wear of the three coatings all increase, and the friction coefficient and wear of the PTFE coating are the largest, while the MoS2 coating has the lowest friction coefficient and wear. Under low viscosity lubricant, the friction coefficient of the MoS2 coating is 2.1%–5.4% and 20.0%–24.3% lower than that of the SiO2 and PTFE coating, respectively. The friction coefficient and wear fluctuation rate of the MoS2 coating is the smallest when the lubricant viscosity decreases, which indicates that the MoS2 coating has excellent stability and adaptability under low viscosity lubricant. Originality/value To reduce the piston skirt wear caused by low viscosity lubricant in heavy-duty diesel engines, the friction and wear adaptability of three novel composite coating materials for piston skirts were compared under 0 W-20 low viscosity lubricant, which could provide a guidance for the application of wear-resistant materials for heavy-duty diesel engine piston skirt.