Numerical Simulation on Influence of the Spray Injector Type in a DISI Engine at Part-Load under Stratified Operation

This work investigates through numerical simulation the influence of two types of hollow cone fuel injectors, an inwardly and an outwardly opening types, on a direct injection spark ignition engine, at part load and under stratified charge operation. By maintain fixed spark timing, the end of injection is varied and compared among the two cases, while targeting for the same gross imep output. The main results are that the outwardly opening injector case resulted in better fuel-air mixture preparation, even with a late end of injection. This led to higher combustion efficiency and lower unburned hydrocarbon, CO and soot emissions, while increasing NOx emissions. The 10-90% MFB burn duration is higher for the outwardly opening injector case.