Tribological properties of modified jojoba oil as probable base stoke of engine lubricant

Abstract

This paper investigates the tribological characteristics of modified jojoba oil (MJO) as a base stoke for SAE20W40 mineral oil (LO). In addition, a graphene nanoparticle was also added as an additive in MJO and studied for its performance. MJO was obtained from a two-stage transesterification process: acid esterification and base esterification. Six samples were formulated with the partial replacement of modified jojoba oil as 0, 10, 20, 30, 40 and 50 % by volume to the SAE20W40 mineral oil. Tribological tests were conducted on a four ball tribometer test rig under extreme pressure and anti-wear conditions with the formulated blends. Subsequently, 0.075 wt% of graphene nano additive was added in the above mentioned oil ratios and investigated once again in a four ball tester. Surface analysis was carried out, using scanning electron microscope (SEM). The experimental results showed that the blend of 20 % jojoba oil exhibited a lower wear scar diameter than other blends at extreme load conditions. An addition of 0.075 wt% of graphene nano-additive to the formulated blends also enhanced its lubrication properties. The surface characteristic study revealed that the addition of nano additives witnessed lesser wear scars with 10 and 20 % of jojoba blends. Among the blends, 20 % of jojoba oil was considered as an acceptable blend to enhance the mineral properties in comparison with SAE20W40 mineral oil.