Effect of copper nanoparticle concentration on tribological performances of cylinder liner piston ring

The performance of cylinder liner piston ring (CLPR) that worked under harsh conditions significantly affected the reliability of diesel engines. Nano-copper lubricant additives have recently been introduced due to their good anti-wear properties. This study aims to gain insights into the interactions between concentrations of nano-copper lubricant additives and the tribological performance of CLPR. Tests are performed on a reciprocating sliding test rig under different operating conditions, and the tribological performances are characterized by the friction coefficient, wear mass losses, and morphologies of worn surface. The experimental results indicated that the optimal concentration of nano-copper additives is 2 wt%. Additionally, deposition of the Cu nanoparticles on the worn surface during the friction process facilitates the formation of the mending layer. These findings would aid to provide a technical reference for the application of nano-copper additives in diesel engines.