Biodiesel is a renewable, clean-burning Diesel replacement. Biodiesel is made from vegetable oils or animal fats. It can be used as a fuel for vehicles in its pure form, but it is usually used as a Diesel additive to reduce exhaust emissions. Numerous studies have been performed on effects of various biodiesels on engine performance and emissions; however, in those studies, less attention has been paid to the availability (exergy) of engine processes. In this investigation, various biodiesel blends have been tested experimentally on a four-cylinder turbocharged Diesel engine. Engine energy, exergy and economic analysis have been performed using the experimental data. The results showed that the structural oxygen content of biodiesel improves the combustion efficiency. However, the engine’s thermal efficiency decreases due to the lower heating value of the biodiesel. Also, destruction of exergy increases when using biodiesel. Among various biodiesel blends, the 15% biodiesel–Diesel blend shows an optimum condition. In this case, the engine power slightly decreases, and both the thermal efficiency and the exergetic efficiency increase. Also, the highest combustion efficiency was observed. The results of emissions economic analysis showed that all biodiesel blends were more affordable than Diesel fuel. The results of full economic analysis (emissions, fuel cost, fuel consumption and engine power loss) showed that only the 15% biodiesel–Diesel blend was more affordable compared to Diesel.

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