某发动机试验中活塞碎裂原因分析

Reasons Analysis of the Piston Fractured in Engine Tes

发动机在试验过程中,会发生很多故障或是零部件失效的案例,本文分析了某发动机搭载变速器进行动力总成动态试验过程中发动机活塞碎裂的原因,根据鱼骨图排查问题根本原因的思路,从发动机硬件、燃烧系统、发动机控制及装配缺陷四个方面分析了发动机在试验过程中活塞碎裂的根本原因,经过对零部件质量、发动机标定控制以及装配异常情况的分析,最终确认导致发动机活塞碎裂的原因是:发动机在0~180 km/h极限急加速工况下,发生连续多次爆震异常燃烧,强大的爆发压力导致火花塞瓷件小头断裂,进而异常燃烧导致活塞碎裂。通过优化发动机标定数据更改发动机基础点火角减少爆震趋势,减少发动机在极限急加速工况下发生爆震的概率及次数,解决了发动机爆震异常燃烧导致发动机毁机问题。

In the process of engine test,there will be many cases of engine failure or parts failure.The paper analyzes the reason of piston fractured in the powertrain dynamic durability test,The train of thought of checking the root cause of the problem according to the fishbone diagram,The root cause of piston fracture in engine test was analyzed from four aspects of engine hardware,combustion system,engine control and assembly defect,Finally,it was confirmed that the reason leading to the piston fractured of the engine was as follows:under the extreme acceleration condition of 0~180km/h,the engine suffered from repeated abnormal detonation combustion,and the strong explosion pressure led to the fracture of the spark plug porcelain,and then the abnormal combustion led to the piston fracture.By optimizing the engine calibration data and changing the engine base ignition angle to reduce the knocking trend,reducing the probability and times of the engine knocking under extreme acceleration condition,and the problem of engine failure caused by abnormal combustion of engine knocking is solved.