Abstract： To investigate the combustion and emissions of small agricultural diesel engine fuelled with methanol/biodiesel, the calculation model of the combustion process of 186FA diesel engine was established by a 3D CFD software. The model was validated by comparing the experimental values with simulation results. The combustion processes and the emissions of biodiesel and biodiesel with 15% methanol (BM15) were calculated at 3 000 r·min-1 and 5.7 kW. The results show that compared with biodiesel, the ignition delay period with BM15 as fuel is increased, and the corresponding crank angle of heat release rate is prolonged with slight decrease of the maximum cylinder pressure. However, the maximum rate of pressure rise and the maximum rate of heat release are increased slightly. The maximum combustion temperature changes lightly with narrowed high temperature zone. When the crank angle is from 370.0° to 400.0°, the low concentration area of O2 is bigger than that with biodiesel as fuel, and the average concentrations of NOx and soot are decreased.
2015, Vol. 36 
