Experimental investigations were carried out in a single cylinder, four stroke, air cooled direct injection (DI) diesel engine, fueled with bioethanol, adopting the fumigation technique. Bioethanol produced by the fermentation of Madhuca indica flower was used as an alternative fuel in this investigation. Bioethanol was fumigated at four different flow rates, viz., 0.24, 0.48, 0.96 and 1.22 kg/h in the suction, with the help of a vaporiser and a microprocessor controlled injector. The results of the combustion, performance and emissions of the engine, running with the bioethanol fumigation, were compared with those of the diesel operation. The results indicated that, the bioethanol fumigation exhibited an overall longer ignition delay of 2-3 degrees CA for all the flow rates in comparison with diesel, at full load. Bioethanol fumigation at the flow rate of 0.48 kg/h gave a better performance and lower emissions than that of other flow rates. The maximum brake specific nitric oxide (BSNO) and smoke emissions were found to be lower, by about 24.2% and 25% in the bioethanol fumigation, compared to that of diesel operation at full load. (C) 2014 Elsevier Ltd. All rights reserved.