Effects of Oxidation Upon Long-term Storage of Karanja Biodiesel on the Combustion and Emission Characteristics of a Heavy-Duty Truck Diesel Engine 2021-01-1200

The presence of unsaturated methyl esters in biodiesel makes it susceptible to oxidation and fuel quality degradation upon long-term storage. In the present work, the effects of oxidation of Karanja biodiesel upon long-term storage on the combustion and emission characteristics of a heavy-duty truck diesel engine are studied. The Karanja biodiesel is stored for one year in a 200 litres steel barrel at room conditions to mimic commercial storage conditions. The results obtained show that compared to diesel, the start of injection of fresh and aged biodiesels are advanced by ~2-degree crank angle, and the ignition delay time is reduced. Aged biodiesel showed a slightly smaller ignition delay compares to fresh biodiesel. The fuel injection and combustion characteristics of fresh and aged biodiesels were similar at all the load conditions. Both fresh and aged biodiesels produced higher oxides of nitrogen (NO_x) and lower smoke emissions compared to diesel. The exhaust emission characteristics of fresh and aged biodiesels were similar at all the load conditions. Overall, the present study concludes that the variations in the combustion and exhaust emission characteristics of the engine operated with fresh and aged Karanja biodiesel stored for one year under commercial conditions are insignificant.