Experimental Study on Mixture Formation and Ignition Processes of Spray Injected by Hole-Type Nozzle for DISI Engine
The purpose of this study is to investigate the spray characteristics and ignition stability of gasoline sprays injected from a hole-type nozzle. Using a single-hole VCO (Valve-Covered-Orifice) nozzle, the spray characteristics were studied with LAS (Laser Absorption Scattering) technique, and then flame propagation and ignition stability were investigated inside a high temperature high pressure constant volume vessel using a high speed video camera. The spatial ignition stability of the spray at different locations was tested by adjusting the position of the electrodes. By adjusting the ignition timings, the stable ignition windows for 3 determined locations where the ignition stability was high at a fixed ignition timing were studied. The flame propagation process was examined using high speed shadowgraph method. Experimental results show that when the ignition points are located on the spray axis, the ignition probability is low.