Experimental Study of Combustion Improvement in Heterogeneous Combustion Field by Using New Type Multi-Impinging Injection System

Direct injection has been widely used on internal combustion engine to reduce combustion products and achieve high thermal efficiency. However, it is important to notice the problems like the fuel adhere on the combustion chamber wall surface, which would cause particulate emission. From this point, previous researches had been carried out to determine the effects of injection timing on the combustion characteristics (combustion behavior, maximum burning pressure and heat release rate) under the heterogeneous combustion field by using impinging injection. Their studies have proved that impinging injection could reduce the unburned components by the effect of spray collision. Next step in this study, experiments have been carried out to examine the effects of fuel distribution and injection conditions while using impinging injection and new developing multi-impinging fuel injection with different fuel types under the heterogeneous combustion field. The new multi-impinging fuel injection has twice fuel injections. Furthermore, the laser diffraction spray analyzer (LDSA) is used to confirm the droplets distribution. A high-speed video camera is used to observe the spray collision and flame behaviors while using the impinging injection.