Özet:

Abstract Alternative fuels such as biodiesel and alcohols have become widespread due to their environmental benefits and availability. In this study, we aimed to expose the performance and emission characteristics of isobutanol addition into diesel-biodiesel blends. Engine tests were performed on a CRDI engine at constant engine speed of 1800 rpm and four engine loads (40, 80, 120 and 160 Nm). Six blends including pure diesel were prepared by mass basis. Mixtures of biodiesel and isobutanol with diesel fuel (B20 and I15) were tested firstly and then three ternary fuels having increasing amounts of isobutanol (I15B20, I25B20 and I35B20) were tested and compared with diesel. The results show that adding biodiesel and isobutanol into diesel increased brake specific fuel consumption (bsfc) from low to mid load, but the gap decreased at high loads. I15B20 and I15 fuels had the closest bsfc to diesel at 160 Nm. Ternary blends generally increased brake thermal efficiency and Pmax value at high loads. While B20 fuel resulted higher NOx emissions, all of the fuel blends increased NOx emissions compared to diesel. Increasing isobutanol proportion in the blends decreased NOx emissions especially at low and full loads. I15B20 and B20 give optimum bsfc at high loads among the blends.

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