Experimental investigation of the effect of tribological performance of reduced graphene oxide additive added into engine oil on gasoline engine wear

Abstract

Good dispersion stability of engine oil added with graphene is the premise of playing its superior tribology property and also the novelty of this study. As the tribological behaviour of a commercialised, fully synthetic 5W40 engine oil upon the incorporation of reduced graphene oxide in sample (0.02 wt%) like (5W40 engine oil + 0.02 wt% Reduced Graphene Oxide) called rGO6 presented superior tribological properties by exhibiting the lowest COF value in our previous work, the same sample was evaluated through a reciprocating tribometer, using steel ball (100 CR6) on a real polished gasoline engine cylinder liner with 5W-40 engine oil to investigate their wear and friction behaviour in boundary lubrication regime. It was found that a rGO6 nano-additive played an active role in lowering the coefficient of friction (3.29%) and increased surface protection by forming a protective layer on a smooth nanorough on rubbing surfaces.

Synergistic effects of graphene additives and piston ring surface treatment on friction properties of engine oil

“…In addition, by comparing the friction coefficients of graphene and reduced graphene oxide lubricants with different concentrations, the variation displays a 'U' shape and the lowest friction coefficient is obtained at the graphene concentration of 0.02 wt% and 0.05 wt%. Beyond this point, the friction coefficient gradually increases with the graphene concentrate [41][42][43][44]. Based on the above study, the mixtures of graphene nanoparticle lubricants with mass fractions of 0.025 wt%, 0.05 wt%, 0.075 wt% and 0.1 wt% (hereinafter referred to as graphene nano-lubricants) were selected for the following experiments.…”

Study on the Lubricating Characteristics of Graphene Lubricants

“…However, the deficiency of dispersibility has hindered their development in lubricating oil. Ka et al [21] explored the tribological properties of graphene as an oil additive. After thorough research work [22], graphene was found to be prone to agglomerating in acidic lubricating oil and found to be unstable in alkaline solvent [23,24].…”