AbstractEthyl levulinate (EL) can be produced from bio-based levulinic acid (LA) and ethanol. Experimental investigations were conducted to evaluate and compare the performances and exhaust emission levels of ethyl levulinate as an additive to conventional diesel fuel, with EL percentages of 5%, 10%, 15% (with 2% n-butanol), and 20% (with 5% n-butanol), in a horizontal single-cylinder four stroke diesel engine. Brake-specific fuel consumptions of the EL-diesel blends were about 10% higher than for pure diesel because of the lower heating value of EL. NOx and CO2 emissions increased with engine power with greater fuel injections, but varied with changing EL content of the blends. CO emissions were similar for all of the fuel formulations. Smoke emissions decreased with increasing EL content.