직분식 가솔린 인젝터의 분사 조건에 따른 분무 특성 분석

Abstract

Recently GDI(Gasoline Direct Injection) engine is spotlighted to achieve higher thermal efficiency under partial loads and better performance at full loads. To realize this system. it is essential to make both stratified combustion and homogeneous combustion. When compared to PFI(Port Fuel Injection)engine. GDI engine needs more complicated control and optimal design with injection system. In addition, spray pattern must be optimized according to injection timing because ambient pressure in combustion chamber is also varied. Thus spray structure should be analyzed in details to meet various conditions. In this experimental study, two types of visualization system were developed to simulate compression stroke and intake stroke, respectively. With an increase of the ambient pressure, the penetration length tends to decrease due to rising resistance caused by the drag force of the ambient air. Spray characteristics impinged on the piston has a significant effect on mixture stratification around the sparkplug. These results provide the information on macroscopic spray structure and design factors for developing GOI injector.