Present work deals with the failure analysis of heavy-duty diesel engine piston used in transport utility vehicles. The piston under consideration has failed at 302763km. Failure mode and effect analysis (FMEA) method is used to identify the engine component having significant contribution in failure. Identification of piston failure has been carried out using FMEA and risk priority number (RPN) for engine components. Experimental analysis of failed piston has been carried out using Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS) and X-Ray Diffraction (XRD) techniques. SEM was employed to speculate the type of failure of piston. Carbon deposition on the piston surface has been observed. EDS of failed piston has also been carried out to identify levels of unnormalized constituent elements contributing to piston failure. From EDS, presence of unnormalized carbon and oxygen is identified and reveal conformability with the failure analysis. Significant percentage of carbon and oxygen at different locations on the piston surface is observed, leading to conclusion of temperature variations inside the cylinder during working. Inferences drawn from piston failure analysis reveal the causes and consequences of failure reasons. The presence of excess carbon on the piston surface indicates the knocking and overheating phenomenon. Remedial measures in addition to periodic maintenance of engine and replacement of worn out gasket to avoid piston failures are presented in this research.

目前的工作涉及用于运输多用途车辆的重型柴油发动机活塞的故障分析。所考虑的活塞在302763km处失效。故障模式和影响分析（FMEA）方法用于识别对故障有重大贡献的发动机部件。活塞故障的识别已使用FMEA和发动机组件的风险优先级编号（RPN）进行。已经使用扫描电子显微镜（SEM），能量色散谱（EDS）和X射线衍射（XRD）技术对失效的活塞进行了实验分析。SEM被用来推测活塞的故障类型。已经观察到在活塞表面上的碳沉积。还进行了失效活塞的EDS，以识别导致活塞失效的非标准化成分的水平。从EDS中，可以识别出存在未归一化的碳和氧，并显示出与失效分析的一致性。在活塞表面上不同位置观察到大量的碳和氧百分比，从而得出在工作期间气缸内温度变化的结论。从活塞故障分析得出的推论揭示了故障原因的原因和后果。活塞表面上存在过量的碳表明爆震和过热现象。在这项研究中，除了定期保养发动机和更换磨损的垫片以防止活塞故障外，还提出了补救措施。在活塞表面上不同位置观察到大量的碳和氧百分比，从而得出在工作期间气缸内温度变化的结论。从活塞故障分析得出的推论揭示了故障原因的原因和后果。活塞表面上存在过量的碳表明爆震和过热现象。在这项研究中，除了定期保养发动机和更换磨损的垫片以防止活塞故障外，还提出了补救措施。在活塞表面上不同位置观察到大量的碳和氧百分比，从而得出在工作期间气缸内温度变化的结论。从活塞故障分析得出的推论揭示了故障原因的原因和后果。活塞表面上存在过量的碳表明爆震和过热现象。在这项研究中，除了定期维护发动机和更换磨损的垫片以防止活塞故障外，还提出了补救措施。