Abstract: This paper focuses on the failure of the oil passage plug seal in a certain range extender. To prevent oil leakage from the plug seal under thermal engine conditions and ensure the stability of the range extender's lubrication system oil pressure, this study uses fault tree analysis (FTA), differential scanning calorimetry (DSC), infrared spectroscopy and other methods to determine that the leakage is caused by abnormal moisture content in the sealing adhesive during production, resulting in a rapid decrease in the tightening torque of the plug under thermal engine conditions, ultimately leading to leakage. By optimising the plug sealing process, adjusting the plug diameter, and improving storage conditions, the issue of oil leakage in some range extenders during durability testing was effectively resolved, reducing the risk of oil leakage after mass production of the vehicle, and providing a reference for technical personnel in this field for testing and research on the sealing performance of range extenders.

Key words: screw plug oil leakage; fault tree analysis; differential scanning calorimetry; seal failure; moisture content; torque attenuation

摘要： 文章围绕某增程器的油道螺堵密封失效进行研究。为抑制热机状态下螺堵密封漏油的 情况，保证增程器润滑系统机油压力稳定，通过故障树分析（FTA），利用差示扫描量热法 （DSC）、红外光谱检测等方法，发现其渗漏原因为生产过程中密封胶含水量异常，热机状态 下螺堵拧紧力矩急剧衰减，最终导致泄漏。通过油道螺堵涂胶工艺优化、油道螺堵大径调整、 存储条件改善等多重措施，有效解决了耐久试验期间部分增程器漏油问题，降低了车型量产 后的漏油风险，同时为该领域相关技术人员对增程器密封性的测试研究提供了一定依据。

关键词: 螺堵漏油；故障树分析；差示扫描量热法；密封失效；含水量；力矩衰减