Performance of engine oil blended with various non-edible vegetable oils as eco-friendly lubricant in extreme pressure conditions

This study intends to investigate the extreme pressure performance of the formulated eco-friendly lubricant S80C10J10, as well as the pure oils of SAE 15W40 engine oil, castor oil, and jatropha oil. Based on the analytical hierarchy process, S80C10J10 is the best eco-friendly lubricant choice. S80C10J10 (80% S100, 10% C100, and 10% J100) was blended with 80% SAE 15W40 engine oil (S100), 10% castor oil (C100), and 10% jatropha oil (J100) using the sonification technique in an ultrasonic homogenizer. A four-ball tribometer was employed to conduct a tribological test in compliance with the American Society for Testing and Materials D2783. A profilometer and a scanning electron microscope fitted with an energy dispersive X-ray spectroscopy were employed to analyse surface morphologies. S80C10J10 reaches the weld point at a load-carrying capacity of 1569 N, which is comparable to that of S100 and J100. S80C10J10 achieved the lowest coefficient of friction (COF) and wear scar diameter (WSD) in the regime of immediate seizure. This performance can be attributed to the effects of formulation on fatty acid content, additives, and the viscosity index. S80C10J10 also recorded the highest load wear index (LWI) at 1047.1, with higher LWI values being preferable. Furthermore, S80C10J10 demonstrated a 20% reduction in mineral oil consumption, thereby helping to slow down the depletion of natural resources. The results of this study indicate that environmentally friendly lubricating oils can enhance lubrication effectiveness in automotive engine systems and machinery, making them a viable alternative to petroleum-based lubricating oils in today's industry.