COMPARATIVE TRIBOLOGICAL AND THERMO-MECHANICAL PERFORMANCE ASSESSMENT OF A POLYOL-ESTER-BASED BIO-LUBRICANT SYNTHESIZED FROM JATROPHA CURCAS SEED OIL IN A COMPRESSION IGNITION ENGINE

Abstract

The growing environmental and energy challenges associated with petroleum-based lubricants necessitate the exploration of sustainable, biodegradable alternatives. This study presents a comprehensive performance evaluation of a bio-lubricant synthesized from Jatropha curcas seed oil vis-à-vis a commercially available mineral-based lubricant. Controlled engine tests were carried out on a four-cylinder, four-stroke compression ignition (CI) engine to evaluate the comparative effects of both lubricants on torque, brake power, brake specific fuel consumption (BSFC), and exhaust gas temperature (EGT) under graded load conditions. The synthesised bio-lubricant demonstrated appreciable improvements in fuel economy (≈4.5%), lower oil consumption, reduced iron wear content, and minimized piston deposits relative to the mineral oil. Statistical evaluation using paired t-tests showed significant performance differences (p < 0.001), indicative of improved tribological and thermal stability of the synthesized lubricant. The study substantiates the feasibility of Jatropha curcas-based lubricants as viable eco-compatible substitutes for petroleum-derived engine oils, promoting sustainable lubrication technology.