VISUALIZATION OF FUEL SPRAYS FOR STRATIFIED COLD STARTS IN GASOLINE DIRECT INJECTION ENGINES

摘要: About 90% of the unburned hydrocarbons (UBHC) emissions from port-fuel injected gasoline engines are emitted during cold starts, before catalyst reaches light-off temperature. In Gasoline Direct Injection starts can be made much cleaner by using modern fuel injectors operating at high pressures and injecting late compression stroke to deliver a stratified charge, thereby enhancing fuel’s rate evaporation reducing wall wetting. The objective this study was assess relative importance variables that influence formation characteristics sprays generated in such conditions. For this, high-speed camera used acquire images measure an outward-opening piezo-actuated injector into pressurized spray chamber which temperature could cooled temperatures as low 243 K (-30 oC). varied parameters were pressure, back-pressure, injection strategy reliable ignition spark plug should positioned vortex they create. results show if pressure is reduced 5 MPa injector’s design 20 MPa, it potentially start, not created will present spark. However, multiple injections found have relatively weak effects on formation.