An experimental investigation of tribological behavior of nahar oil based lubricant and its performance emission analysis

Bio-lubricants are drawing amplified attention in several industrial and automotive applications. It is imperative to improve the wear resistance of the piston ring to minimize frictional power losses in automotive engines. The present investigation explores the effect of Nahar oil as a bio-lubricant on the tribology of piston rings. This study checks the capability of Nahar oil bio-lubricant to replace the widely popular mineral oil-based lubricants and its effects on an internal combustion engine. These are non-toxic, non-edible seeds abundantly available in the northeastern region of eastern India. The tribological properties like the coefficient of friction, specific wear rate, and indentation depth are compared for both bio-lubricant and commercially available lubricants on piston ring material made of Chrome alloy steel (AISI no. E-52100). Additionally, engine emissions are compared when lubricated with Nahar oil and standard engine oil. It is seen that pure Nahar oil obtained from extracting Nahar seeds is quite viscous, having a density of 0.9321 gm/cc @ 30 °C, which is one of the desired properties for its use as bio-lubricants. Also, its flash point is 212 °C, which makes it safe for use as a lubricant, as there is hardly any chance of producing unpleasant gas during its use. Nahar oil-based bio-lubricant has a reasonable viscosity index, affecting engine performance and lowering carbon dioxide (CO2) and other greenhouse gas emissions. The study specifies that, at a medium-load range, the coefficient of friction of Nahar oil bio-lubricant does not deviate too much from mineral oil lubricant. Infect with more extended duration, these tribological properties grow similarly for both lubricants. Although the brake thermal efficiency of the engine has decreased by approximately 8–11% with the variation of loads with the use of bio-lubricant and biodiesel, their combined effect helps to reduce harmful emissions like Nitrox oxide (NOx) and unburned hydrocarbon (HC) decrease by 19% and 16.5%, which is significant enough to contribute in the improvement of environmental health.