The combined effects of cobalt chromite nanoparticles and variable injection timing of preheated biodiesel and diesel on performance, combustion and emission characteristics of CI engine

The performance, emission, and combustion characteristics of kapok methyl ester biodiesel in the base engine were analyzed. The kapok methyl ester oil is heated up to 110 °C employing a preheating method to reduce the fuel’s viscosity and density. The preheated oil is blended with the base fuel (i.e., diesel) to make various fuel blends. Many research findings have shown that the B20 (i.e., 20% biodiesel and 80% diesel) blend reveals superior performance, emission, and combustion characteristics in the diesel engine. Preheated oil was mixed with cobalt chromite nanoparticles in the different dosages of 50 ppm, 100 ppm, 150 ppm, and 200 ppm, respectively. When using this biodiesel in a diesel engine, the oxide of nitrogen increases. To overcome this problem, the injection timing concept was used. The injection timing was varied by 19 crank angle degree (CAD) bTDC (Retardation), 23 CAD bTDC (Standard), and 27 CAD bTDC (Advanced). The brake thermal efficiency increased with the blends B20 with cobalt 200 ppm in Retardation by 7.2% as compared with the started ignition delay. The hydrocarbon and carbon monoxide decreased in the blends B20 with cobalt 200 ppm in Retardation by 37.86% and 41.66% as compared to the standard injection timing. The oxides of nitrogen and carbon monoxide of blend B20 with cobalt 50 ppm in Retardation decreased by 16.45% and 9.5% when correlated to normal injection timing. The biodiesel of kapok oil methyl ester is utilized as an alternative fuel in the base engine to obtain better optimum results.