Fuel, Vol.235, 288-300, 2019
Study of combustion, performance and emissions of a diesel engine fueled with ternary fuel in blended and fumigation modes
The present study aimed to compare the combustion, performance and emissions of a diesel engine fueled with diesel, biodiesel and ethanol in the blended and fumigation modes. In addition, a combined fumigation and blended mode (F + B) of fueling was introduced to understand its behavior in comparison with the blended and fumigation modes. In the blended mode, the fuel was composed of 80% diesel, 5% biodiesel and 15% ethanol (DBE), by volume. In the fumigation mode, a mixture of biodiesel and ethanol ( BE) was injected into the intake manifold and diesel fuel was used as the main fuel. In the F + B mode, half of the BE mixture was injected into the intake manifold and another half of the DB mixture was mixed with diesel to form the main fuel. The experiments were conducted at a speed of 1800 rpm with five engine loads at a constant mixture percentage of D80B5E15 for the three fueling modes to provide the same fuel composition for comparing the effects of the three fueling modes. According to the average of five loads, compared to the pure diesel operation, the blended mode causes increases in peak heat release rate (HRR), ignition delay (ID), BSFC, CO, HC and NO2; drops in duration of combustion (DOC), CO2, NOX, PM, total number concentration (TNC) and geometric mean diameter (GMD); and similar peak in-cylinder pressure and BTE. While the fumigation mode leads to higher peak HRR, DOC, BSFC, CO, HC, NO2 and TNC; lower ID, BTE and NOx; and similar peak in-cylinder pressure, CO2, PM and GMD in comparison with the diesel mode. In addition, the F + B mode has the effects between those of the fumigation and blended modes. Among the three fueling modes, the blended mode gives the highest engine performance and lowest emissions, except for NOx. In contrast, the fumigation mode gives the worst engine performance and emissions, except for NOx.