Investigations using supercritical spray platform, which allows gasoline at low sub-critical state, subcritical state and supercritical state respectively, were made to demonstrate the Subcritical/ Supercritical Spray Characteristics of a Multi-Hole Gasoline Direct Injector. The experimental results show that the spray pattern and spray characteristics (i.e. spray penetration distance, spray area and spray perimeter) varied greatly under different state. In subcritical state, the spray characteristics of gasoline is similar to the phenomenon of "flash bfueling",appearing spray entrainment and spray collapse, then spray penetration distance and area drop significantly. In supercritical state, the six-hole gasoline spray is composed by the thick-core region and the thin-diffusion region, and Mach disk is observed at the outlet of the nozzle, then spray penetration distance and area increases sharply. In addition, by comparing the spray characteristics of six-hole and single-hole GDI injector, result shows the single-hole injector is more conducive to the development of supercritical gasoline.
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