基于激光诊断技术的汽油直喷发动机喷雾机理

Mechanism of spray in gasoline direct injection engine based on laser diagnostics

汽油直喷喷雾贯穿度、锥角等宏观喷雾特性,对研究汽油直喷发动机喷雾及燃烧的发生、发展具有重要意义。在设计并建立汽油直喷(GDI)系统的基础上,搭建定容燃烧弹系统和激光测试系统,基于LSD测试技术,研究了喷油压力和背景压力对汽油直喷宏观喷雾特性的影响。通过试验发现,随喷油压力增加,相同喷油时刻下的贯穿度逐渐增加。随背景压力增加,相同喷油时刻下的贯穿度逐渐减少。在不同喷油压力和背景压力下,随着喷射时间的发展,贯穿度均逐渐增加,喷雾锥角为38°~50°。

It is important to study the direct injection spray penetration and spray cone angle characteristics of gasoline for the occurrence and development of spray and combustion characteristics in gasoline direct injection engine.Based on the design and building of gasoline direct injection(GDI)system,the constant volume combustion bomb system and the optical testing system are established,and based on LSD measurement technique,the influence of injection pressure and back pressure on the spray characteristics of GDI engine is studied in this paper.The experiment shows that with the increase of injection pressure,the penetration at the same injection time gradually increases.With the increase of back pressure,the penetration at the same injection time decreases gradually.Under different injection pressure and back pressure,with the development of injection time,the penetration gradually increases,and the spray cone angle is between 38°and 50°.