Optimization of performance and emission parameters of direct injection diesel engine fuelled with pongamia methyl esters-response surface methodology approach

More demand for fossil fuel and high-rise in the air pollution levels due to combustion of the fossil fuel give us an opportunity to discover some clean and environmental-friendly fuels for the engines. This study includes the optimization of engine operating parameters to obtain an optimum thermal performance of the engine running on pongamia based biodiesel blends. The fuel injection pressure, fuel injection timing, pongamia based biodiesel blends, and engine load were considered as input parameters for the optimization of Brake thermal efficiency, unburnt hydrocarbon, and NOx emission. An experiment was conducted according to the central composite rotating design (CCRD) matrix. The optimum combination of input parameters for maximum performance and minimum exhaust emissions were obtained at 15 degrees bTDC fuel injection timing, 196.36 bar fuel injection pressure, 40% blend of biodiesel with diesel, and 53% engine load. The other biodiesel blends did not perform well during the 40% blend of biodiesel at the prescribed injection timing and pressure. RSM provides a better combination in terms of improving the performance of the engine. Analysis of variance (ANOVA) revealed that all developed models were statistically significant. The predicted combination was validated by confirmatory tests and the error in prediction was found to be within 4%. The percentage error was 2.4%, 4.95%, and 0.93% with respect to BTE, UHC, and NOx For the future work, the combination of different biodiesel blends from various sources can be performed to obtain improved results.