Abstract
The mixture formation process of a D.I. Diesel spray injected by a micro hole nozzle and a high pressure fuel injection system was characterized by means of the laser absorption and scattering (LAS) technique. The LAS technique provides the quantitative measurements of the liquid and vapor phase concentration distributions in the fuel spray, and the spray and mixture properties such as the Sauter mean diameter of the spray, the mass of ambient gas entrained into the spray, the mass of fuel vapor in the spray, and the mean equivalence ratio of the fuel and so on. The injection duration was set to the same for any diameter hole nozzle examined under the same injection pressure. Comparing to the conventional nozzle hole size (0.16mm in diameter) and fuel injection pressure (100MPa), combining the micro hole (80μm in diameter) nozzle and the high pressure (300MPa) fuel injection produces the spray having much smaller Sauter mean diameter, much higher evaporation rate, and much leaner fuel and ambient gas mixture due to the enhanced ambient gas entrainment per unit fuel in the spray.
