Passage parameters study of a new prechamber type combustion system aiming at decarbonization and emission reduction in a diesel engine

To realize decarbonization and emissions reduction, optimization of prechamber passage parameters, including passage inclination angle (PIA) and diameter (PD), was conducted using experimental testing and computational modeling in a heavy-duty diesel engine. The main findings are as follows. For prechamber cases, both higher PIA and PD result in a decrease in the lean mixture proportion in the cylinder, a slight increase in the combustion duration, and a great reduction in the TKE peak. In the late combustion stage, higher PIA causes the disturbance range of the jet flame shrunken; higher PD causes the penetration and impact scope of the jet flame decreased. Both higher PIA and PD decrease the exhaust loss, increase the wall heat transfer loss and reduce the ITE_g. For the optimal prechamber case with PIA of 30° and PD of 2 mm, the mixing quality is greatly improved, the combustion duration is decreased by 49.3 %, the combustion loss decreases, the exhaust loss decreases, despite the wall heat transfer loss increases, the ITE_g increases by 6.41 %, the NO_x, soot and CO emissions decrease by 2.8 %, 44.4 % and 46.3 %, respectively, compared to the original engine. The findings can provide theoretical guidance for application of prechamber technology in diesel engines.