Used sunflower oil was blended with grade No. 2-D diesel fuel at a ratio of 20 / 80 (v / v). The fuel blend was tested in a diesel engine with a precombustion chamber at speeds between 1200 and 2100 rpm. The fuel blend and the diesel fuel were rated according to standard test methods. It was found that for short-term use the fuel blend has characteristics similar to those of the baseline diesel fuel and that it displayed less smoke emission than the diesel fuel.