In-Cylinder Pressure Characteristics of a D.I. Heavy Duty Diesel Engine on Biodiesel Fuel

A Cummins N14-410 diesel engine was operated on four fuels produced by blending Biodiesel (methyl tallowate) and no. 2 diesel fuel. Engine in-cylinder pressure data were collected at various engine speeds and used to evaluate the peak pressure, indicated mean effective pressure (IMEP), rate of change of pressure, rate of heat release, mass fraction of fuel burned, and charge temperature with respect to crank angle. Peak cylinder pressures for each fuel blend at all engine speeds were lower than peak pressure for no. 2 diesel fuel, the IMEP values for all fuel blends were less than that of no. 2 diesel fuel. The differences in IMEP values correlated with the differences in power output of the engine. The maximum rates of pressure rise for all fuel blends were less than for no. 2 diesel fuel. The rate of heat release decreased with increasing engine speed as well as, with the amount of methyl tallowate in the fuel blend. Peak rate of heat release for all fuel blends were less than for no. 2 diesel fuel. When methyl tallowate was blended with no. 2 diesel fuel, the shift in the location of peak heat release was slightly away from top dead center (TDC). Ignition delay slightly increased when methyl tallowate was blended with no. 2 diesel fuel at peak torque conditions but at peak power, ignition delay was not affected by the type of fuel blends. On the other hand, burn duration slightly decreased with increase in methyl tallowate in the fuel blend at peak torque condition and there was no significant effect on burn duration at peak power condition. The charge temperature decreased with increase in methyl tallowate content of the fuel blends. A reduction in charge temperature can help reduce NO_x, emissions. It was concluded that the fuel blends used in this study would have no detrimental long-term effects on engine performance, wear, and knock.