某大型轮式拖拉机发动机在工作过程中发生喷油嘴卡死现象。拆卸喷油嘴后发现内部有金属类碎片。通过对比碎片和喷油器总成中相关零件的显微组织, 发现碎片组织与喷油器总成中的高压油管的显微组织一致, 将高压油管纵向剖开后, 发现油管接头处残留有在机加工时形成的金属毛刺, 得出造成喷油嘴失效的碎片来源于高压油管的金属毛刺。

In the working process of a large wheeled tractor engine, the oil nozzle jammed phenomenon was found. After dismantled the oil nozzle, some metal fragment was found inside. By comparing the microstructure of fragment and the related parts in fuel injector assembly, it was found that the microstructure of fragment was consistent with the microstructure of high-pressure oil pipe in fuel injector assembly. After cut the high-pressure oil pipe longitudinally, some metal burrs formed during machining were found in pipe joints. It was showed that the fragment caused oil nozzle failure was from metal burrs in high-pressure oil pipe.