Hiromasa Kubo

Experimental Characterization of Flat-Spray Injector in Gasoline Direct Injection Engines

A flat spray pattern was proposed in order to improve conventional stratified-charge combustion systems in a direct-injection (DI) gasoline engine. Swirl injectors with a V-groove nozzle and a rectangular-groove nozzle were newly designed. The characteristics of newly designed injector nozzles were examined experimentally under various ambient pressure and fuel pressure conditions. The fuel spray characteristics were tested in a pressure chamber. The injected fuel-spray was illuminated by a YAG-laser sheet and their images were captured by CCD cameras. The atomization of fuel spray in the V-groove and U-groove nozzle was also investigated experimentally. It was shown that the V-groove and the U-groove nozzles generate a well-atomized flat fuel-spray pattern that can be controlled by adjusting the groove-depth. It was also shown that the flat fuel-spray pattern was not susceptible to ambient pressure variations.