The fuel flow pattern in the fuel injection nozzle of diesel engine is a complex and changeable phenomenon, which is easily affected by various factors, bringing the differences of flow patterns between multiple injection cycles. To solve the above problem, a visual experimental platform of fuel injection nozzle was built, in which the 100 injection cycles of diesel engine on the same working condition were photographed via shadowgraphy to study the difference in fuel flow pattern in the nozzle by ensemble average processing method. The cyclic variation rate K of fuel flow pattern is defined. Results demonstrate that the fuel flow pattern tends to be the same in multiple fuel injection cycles, but there is a strong randomness at the starting of injection and after ending of injection; the K can be reduced by decreasing the injection pressure and the inclination angle of orifice, so that the fuel flow pattern in the nozzle tends to be consistent.

柴油机喷油嘴内的燃油流型是一种复杂多变的现象，容易受到各种因素的影响，导致多次喷射循环之间的流型存在差异。为解决上述问题，搭建了喷油嘴可视化实验平台，对柴油机在相同工况下的100次喷油循环进行投影，通过整体平均处理研究喷油嘴内燃油流型的差异。方法。定义了燃料流型的循环变化率K。结果表明，在多次喷油循环中，燃油流型趋于一致，但在喷油开始和喷油结束后具有较强的随机性；该ķ 可以通过降低喷射压力和孔口倾角来减小，使喷嘴中的燃料流型趋于一致。