▎ 摘　　要

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.