燃油喷嘴封严弹簧失效与发动机冒烟的关系

通过流量试验对比分析、燃油喷嘴结构分析以及弹簧失效机理分析对某发动机长期存在的冒烟故障的根本原因进行了探索性研究.对冒烟发动机和无冒烟发动机燃油喷嘴及总管流量试验的实证分析表明：发动机冒烟故障的根本原因在于外场服役期间慢车工况某些燃油喷嘴反压降低导致的总管流量不均.对冒烟发动机14个燃油喷嘴的结构实证分析表明：发动机服役中燃油喷嘴及燃油总管流量特性发生漂移的根本原因在于封严弹簧顶紧机制的丧失，而造成顶紧机制丧失的根本原因是弹簧端过度不平导致螺母旋合过程中弹簧在不平端受力不均以致不规则歪倒塑性变形.

Relationship of failure of fuel nozzle seal spring and engine smoking failure

The ultimate cause of the long-existing smoking failure of an engine type was explored by an explorative study of comparison analysis of flow tests, fuel nozzle structure analysis and spring failure mechanism analysis. The proof analyses of fuel nozzle and manifold flow tests on a smoking engine and a non-smoking engine show that the ultimate cause of engine smoking failure is the un-uniformity of manifold flow at the idle condition resulting from back pressure decrease on some fuel nozzles. The proof analysis of the structure of 14 nozzles of a smoking engine shows that the ultimate cause of the drifts of nozzle and manifold flow characteristics are the loss of the pressing mechanism of the seal spring, and the ultimate cause of that is the excessive un-evenness of the spring end leading to un-uniformity of pressure on the uneven end during nut screwing, which leads to abnormal fall-down and plastic deformation of the spring.