Abstract:

The effects of one-pilot injection strategy and two-pilot injection strategy on combustion and
emission are investigated in a four-cylinder, turbocharged, high pressure common-rail diesel engine. The pilotmain
injection intervals, the pilot injection quantities, the diesel combustion pressures, the heat release rates,
and the emissions of NO, HC, CO, and soot were measured. The results show that both pilot-main injection
interval and pilot injection quantity strongly affect the pilot combustion heat release and the main combustion
heat release, and that the effect of pilot-main injection interval on main combustion ignition delay is more evident
than the effect of pilot injection quantity. The emission of NO and soot are reduced without obvious deterioration
in HC and CO when choosing appropriate pilot-main injection interval and pilot injection quantity under one-pilot
injection strategy. Using two-pilot injection strategy enhances the mixing of fuel and air. The emission is more
improved, when the two-pilot injection interval is less.

Key words: diesel engines, pilot injection strategy, combustion, emission, experiments