直喷汽油机喷油器积碳对喷雾落点及喷雾一致性的影响

Effects of Carbon Deposition on Spray Droppoint and Consistency of a GDI Injector

针对直喷汽油机喷油器积碳问题运用平面激光米氏散射法和白光散射法在喷雾实验台上利用高速摄像机、片激光源和LED光源进行了直喷汽油机喷油器喷雾落点试验及各孔喷雾锥角试验,对比清洁喷油器和积碳喷油器在不同喷射压力下的喷雾落点形态、落点质心位置、各孔喷雾锥角等参数.结果表明:在相同压力下积碳喷油器的流量损失较大;喷雾落点形态变化较大,且分布不均匀,落点区域质心坐标相较于清洁喷油器向喷油器轴线外拓展;积碳喷油器多次独立喷射后喷雾形态和各孔喷雾锥角等参数的一致性变差,且这种一致性差异随着喷射压力的增高而变大.

With the methods of Mie scattering and White LED scattering,the spray droppoint characteristics test and spray cone angle test were conducted on a gasoline direct injection(GDI)engine injector by using high speed camera,LED and plane laser on test benches.The spray droppoint pattern,droppoint barycenter,and spray cone angle of each orifice under different injection pressures were compared between clean injector and fouled injector.The results reveal that the flow loss of fouled injector is larger under the same injection pressure,the spray droppoint pattern has a larger variation and the droppoint distribution is uneven,and the droppoint barycenter of fouled injector spreads outward compared with that of the clean injector.The fouled injector is worse than clean injector in the consistency of spray droppoint pattern and spray cone angle after many independent jets and the difference in consistency becomes more obvious with the increase of injection pressure.