Mechanical Engineering, Urmia University
One of the important problems in reducing of pollutant emission from DI and IDI diesel engines is trade-off between soot and NOx. Split injection is one of the most powerful tools that makes the chance to shift the trade-off curve closer to origin. At the present work, the effect of split injection on the combustion process and emissions of a cylinder IDI diesel engine under the specifications of 5.9 kW maximum engine power and engine speed of 730 rpm has been investigated. The studies of injection timing and split injection parameters, including the delay dwell and the fuel quantity injected between injection pulses are carried out. Three different split injection schemes, in which 10, 20 and 25% of total fuel injected in the second pulse, have been considered. The numerical results show that 25% of total fuel injected in the second pulse which is accompanied with the 20ºCA delay dwell between injections, reduces the total soot and NOx emissions effectively in IDI diesel engines. The predicted values of combustion process and emissions by the model at baseline engine show a good agreement with the corresponding experimental data. This agreement makes the model a reliable tool that can use for exploring new engine concepts.