Degradation of engine components upon exposure to chemically modified vegetable oil - Based automotive lubricant

The present investigation examines the corrosion behavior of vegetable oil-based engine oil-biodiesel environment against automotive engine components, viz., cylinder liner, crankshaft, camshaft, journal bearing and timing gear as a counteractive measure. The biodegradable engine oil was formulated via chemical synthesis route and the thermo-oxidative stability of the biodegradable engine oil was analysed using thermogravimetric analysis. A high-temperature corrosion test rig was developed for the purpose of evaluating the corrosion behavior of biodegradable engine oil and the corrosion results were compared with those of synthetic engine oil SAE20W40 under similar test conditions. The corrosion penetration rate (CPR) of the journal bearing is 0.03270 ​mm/year and 0.0163 ​mm/year for biodegradable and synthetic engine oil respectively and the CPR of crankshaft, cylinder liner, camshaft and timing gear in biodegradable engine oil is 0.0120, 0.0156, 0.0127 and 0.0119 ​mm/year respectively, conversely in SAE20W40, the respective CPR is 0.0110, 0.0133, 0.0117 and 0.0109 ​mm/year. The scanning electron microscopy, X-ray diffraction, energy dispersive spectroscopy analysis of post corrosive surfaces revealed that biodegradable engine oil is prone to corrosion against various lubrication system components as compared to SAE20W40.