Laser texturing of the surface is a known approach to improve the tribological performance of mechanical systems. Many studies focused on optimising surface texture parameters for the piston-ring cylinder liner (PRCL) system. However, little attention is given to explore the effect of the textured surface on additive film formation. In the present work, the effect of a laser textured surface on the formation of additives tribochemical films and its impact on the tribological performance of PRCL system is studied. Commercially available steel piston ring and grey cast iron cylinder liner are used as samples to carry out the experiments using linear reciprocating tribometer. Experiments are carried out at 75 N load, 0.1 Hz frequency and 80°C temperature, using polyalphaolefin as base oil mixed with different additives. It is found that dimples are interfering in the formation of tribo-chemical films. However, the hydrodynamic effect of dimples is contributing to the improvement of lubrication performance even in the presence of additives.

It is well-established that the piston ring/cylinder liner (PRCL) contact is the major contributor to friction losses in the internal combustion engine. While numerous studies have evaluated the individual effect of surface engineering techniques like surface texturing, coating, on the PRCL system, however, its combined effect has not been thoroughly explored. In this work, the combined effect of surface coating and texturing on the frictional properties of piston ring/cylinder liner (PRCL) contact in different lubrication regimes has been simulated using a reciprocating tribometer rig. A cylinder liner of cast iron material and three different types of piston ring coatings, namely Diamond-like-carbon (DLC), chrome, and moly-chrome-ceramic (MCC) were used as samples. Under all lubrication regimes, the coated samples with texturing had better frictional performance compared to non-textured coated samples. The maximum friction reduction was observed for textured DLC coated samples under boundary lubrication regime. This behaviour was proposed to be a result of the synergistic effect of graphitisation and texturing.

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