Failure Mode And Effect Analysis Of Engine Assembly Quality

Engine, as heart of the automobile, has a pivotal role in the whole auto industry, it is an energy conversion device and the source of vehicle power, its quality directly affects the automobile’s driving performance, stability, fuel consumption and environmental protection. As the last stage of engine production, assembly has a great influence on the final quality and performance of the engine, thus, improving the engine assembly quality, reduce the quality problem of the engine assembly process has become the top priority for the engine manufacturers to improve their market competitiveness.In order to reduce the quality problems of engine assembly process, based on the study of traditional failure mode and effects analysis, a new FMEA method based on rough set theory and quality loss function is proposed to analysis and control engine assembly quality. First, according to the characteristics of engine assembly, identify potential failure modes in the assembly process, analyze the failure causes and effects, then determine the weight of risk factors in failure mode analysis; Second, on the basis of potential failure mode analysis, the matrix model of failure modes risk assessment is constructed by the expert system, in order to reduce the subjectivity and vagueness of the data itself, the matrix model of risk assessment is converted into rough domain matrix model based on the rough set theory. Third, combined with the solved rough domain matrix, potential loss of each failure mode is solved by applying multivariate quality loss function model, correcting the potential losses by the correction coefficient based on the historical data, the risk level of failure mode can be sorted according to the corrected potential losses, then, identifying the weak links of the engine assembly system and correct them. Finally, engine assembly process is used as an example to analyze its failure mode and influence, reasonableness and effectiveness of the proposed method are validated by compared the result with the current FMEA method.