The exhaustive and irresponsible use of fossil fuels has created numerous public and environmental health issues in the past few decades. To address this issue, this work has investigated the use of polanga ( Calophyllum inophyllum) biodiesel/diesel blends in a diesel engine. This study focuses primarily on the optimization of performance and emission characteristics of a diesel engine fuelled with polanga-based biodiesel blends. The engine input factors were also investigated for desired optimal thermal performance. In this study, four input parameters, namely, engine loads, blends of polanga-based biodiesel, fuel injection pressure, and fuel injection timing were chosen for analysis. The corresponding engine output responses, namely, brake thermal efficiency, CO, NOx, and smoke emissions, are selected for their optimization by Taguchi method and response surface methodology. The results show that the best setting of above-mentioned input factors is reported at 44% engine load, 13% mixing of polanga biodiesel with diesel, 180 bar injection pressure of fuel, and 21.5 °bTDC injection timing of fuel. The comparison between results obtained by the optimization process and experimental results showed that the deviations were always found to be within the acceptable range of errors.
