Comparison of the Physical and Chemical Properties, Performance, and Emissions of Ethyl Levulinate–Biodiesel–Diesel and n -Butanol–Biodiesel–Diesel Blends

In this study, fuel blends EL5-B10-D85 (5 vol % ethyl levulinate, 10 vol % biodiesel, and 85 vol % diesel), EL10-B15-D75, nBu5-B10-D85 (5 vol % n-butanol, 10 vol % biodiesel, and 85 vol % diesel), and nBu10-B15-D75 were compared on a horizontal, four-stroke, and single-cylinder engine. Ethyl levulinate–biodiesel–diesel (EL-B-D) blends and n-butanol–biodiesel–diesel (nBu-B-D) blends showed good miscibility. Generally, EL-B-D blends were more effective than nBu-B-D blends for decreasing kinematic viscosity, increasing closed cup flash point and oxygen content, although nBu-B-D blends were more effective than EL-B-D blends for decreasing cold filter plugging point and distillation. Overall, when used in a diesel engine, the fuel blends showed a slightly higher brake-specific fuel consumption (BSFC) than neat diesel, with EL-B-D being slightly higher than nB-B-D. EL-B-D blends were more effective than nB-B-D blends for reducing carbon monoxide (CO) emissions and smoke opacity, while nitrogen oxides (NOx) and carbon dioxide (CO2) emissions increases were more obvious in EL-B-D blends. Compared with EL-B-D blends, hydrocarbon (HC) emissions of nBu-B-D blends were higher. The results provide a useful reference for further research of the effects of using these blends on emissions.