Multi-objective optimization of diesel engine performance and emissions fueled with diesel-biodiesel-fusel oil blends...

The interest in research on alcohol-based biofuels is on the rise. Fusel oil is a long-chain alcohol and a by-product of bioethanol synthesis. This study analyzed the effects of blended levels of fusel oil and biodiesel in diesel fuel on the performance and exhaust emissions of a single-cylinder diesel engine. The effects of input parameters (i.e., fusel oil content (%), biodiesel content (%), engine speed (rpm), and engine load (%), each at five levels) on response parameters (i.e., power, torque, fuel consumption, and emission factors, namely NO_X, UHC, CO, and CO₂) were investigated. Different levels were used for analyzing fusel oil (0, 5, 10, 15, and 20%), biodiesel (0, 5, 10, 15, and 20%), engine load (0, 25, 50, 75, and 100%), and engine speed (1400, 1700, 2000, 2300, and 2600 rpm). Response surface method (RSM) was employed to maximize engine performance and minimize exhaust emissions. A blend of D₉₀F₅ B₅ (5% fusel oil, 5% biodiesel, and 90% petro-diesel) and engine speed of 2026 rpm at load 46% were predicted to be an optimal value. Using a 72% desirability function, optimum results for torque (14.2 Nm), power (3.37 kW), and brake-specific fuel consumption (356.9 g/kWh) were also obtained from RSM. Based on the optimized inputs, the optimized values of different output pollutants were 0.14 vol.% for CO, 1.62 vol.% for CO₂, 23.7 ppm for UHC, and 85.17 ppm for NO_X. The result illustrated that use of fusel oil decreased NO_X emissions up to 20%, while UHC and CO emissions increased up to 32% and 22%, respectively. In addition, the use of fusel oil content (up to 10%) in the blended fuels improved the engine power by 5.6%.