Pages 87-88
The ignition phenomena of diesel fuel spray injected with medium injection pressure were investigated and it is clarified that ignition occurs at a certain point near the surface of spray liquid column before breakup. Based on this result, the blowing-off limited ignition model was considered under the concept that the fuel vaporized from liquid surface begins to be activated immediately after the velocity gradient at liquid column surface decreases down to a certain level and this leads to ignition. A functional relation between various factors and ignition delay, derived based on this model, well analyzed the ignition delay data. Ignition investigation using a single cylinder engine revealed that the effects of EGR rate, related to O_2 concentration, can be analyzed comprehensively based on the above model.
