Potential of CuS and CuO nanoparticles for friction reduction in piston ring–liner contact

Abstract

An experimental study on the use of Cu nanofluids as engine oils for reduction of friction in piston ring-liner contact is presented. The Cu nanofluids were prepared using CuS and CuO nanoparticles and blending them in 0.1-6% concentration by weight in the commercial engine oils. The Cu nanoparticles were synthesised and characterised after mixing with the lubricant for their physico-chemical characteristics. The experiments were performed on a reciprocating tribo-tester using actual piston rings and the liners as test specimens. Experiments were performed to investigate the effect of nanoparticle concentration with the change of contact loads and reciprocating frequency on the coefficient of friction. The study reveals that the Cu nanoparticles blended in the engine lubricating oils can significantly reduce friction between piston ring-liner contact, desirable for fuel economy improvement. The Cu nanoparticles are compatible with base lubricants and result in significant friction reduction. The CuS nanoparticles performed significantly better than the CuO nanoparticles.

Tribological Behavior of Ionic Liquid with Nanoparticles

“…Among all nanoparticles, copper oxide (CuO) and zinc oxide (ZnO) have been widely researched due to their excellent tribological properties. The addition of CuO nanoparticles could reduce friction and wear when they were blended into different types of lubricating oils [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. For instance, Kumar et al [ 14 ] presented that the CuO nanoparticles could be mixed with the zinc dialkyldithiophosphates (ZDDP) additive to increase the wear resistance ability of vegetable oil.…”

“…The CuO nanoparticles were also used as additives to improve the anti-wear and extreme pressure performances of coconut oil [ 15 ], palm oil [ 16 ], and canola oil [ 17 ]. Moreover, the CuO nanoparticles were compatible with engine oils and resulted in significant friction reduction [ 18 , 19 ]. A reduction in friction coefficient by 37.9%, 42.9%, and 14.6% for three different concentrations of 0.2, 0.5, and 1.0 wt%, respectively, was observed when CuO nanoparticles were added to a mineral-based lubricant [ 20 ].…”