高环境压力下燃油连续多段喷射喷雾特性研究

A Study on the Spray Characteristics of Fuel Continuous Multi-Injection under High Ambient Pressure

在定容弹中,基于相同的喷油压力、喷油量和环境温度,利用纹影法研究了不同的环境背压和喷油规律下的汽油直喷多孔喷油器的喷雾特性。试验结果表明:边界条件相同时,改变环境背压会影响喷油贯穿距,随环境背压上升,喷油贯穿距先减小后趋于平缓,环境背压由1MPa上升至2MPa时喷油贯穿距减小约12mm,而由2MPa上升至3MPa时基本无变化;喷油规律对喷油贯穿距和雾滴群形态均会产生影响,且在环境背压的影响协同作用下,喷油贯穿距最多可以减小约22mm;多段喷射对雾滴群燃油浓度分布调节作用显著,单段喷射的雾滴群前端密度较高,两段喷射较为均匀,三段喷射后端密度较高,连续多段喷射技术有利于形成高质量的混合气。

The spray characteristics of multi-holes GDI injector was investigated by the schlieren images in a constant volume vessel, on the basis of the same injection pressure, injected fuel quality and ambient temperature. The experimental results show that the penetration length is decreased sharply by 12 mm approximately with the ambient pressure increased from 1 MPa to 2 MPa, while it is changed slightly with the ambient pressure increased from 2 MPa to 3 MPa. The injection regularity not only impacts the penetration length, but also affects the spray pattern. The penetration length is deceased by 22 mm maximum under the joint action of the ambient pressure and injection regularity. Besides the multi injection has great regulation effect on the spray concentration distribution. The single injection has higher spray concentration in the spray front area, the double injection has uniform spray pattern, and the triple injection has higher spray concentration in the spray back area. Therefore, the continuous multi-injection can form a high quality mixture significantly.