Engine Reliability Evaluation Based On Test Technology

Due to the complex work environment and long term high load operation,the engine is a component with a high failure rate for the automobile.O nce the engine failed,which will directly influence on the performance of the vehicle,even may threaten people's life,therefore the reliability analysis of engine has become increasingly important.Reliability test,as a direct and important method to improve the reliability of engines,is getting more and more attention.Taking a type of diesel engine as the research object in this paper,combined with some analysis method,such as finite element,data processing,grey model,and weibull,reliability assessment of the diesel engine or the parts based on various test technology is conducted.Which provides a solid foundation for the modification of the diesel engine and the improvement of the enterprise's core competition.The main works are as follows:(1)Taking 500 hours full load at full speed endurance test to a engine which is in pilot production and validation phase stage,and the weak link of the engine is exposed;The failure element is found and the fault category is determined through dismounting the engine,and the severity of the fault category is sorted in a descending order.The finite element analysis and physical and chemical inspection method is used for the piston,the failure reason is found and the improvement measures is put forward,providing a basis for the design improvement of the engine.(2)A engine is sampled out by the random sampling method,and the engine sensory evaluation,operation evaluation(30 hours reliability test),the collapse of the evaluation and the cylinder liner sampling friction and wear test are conducted,the reliability of the engine and its parts are mastered,some reference are provided for grasping the reliability of the engines in the batch and for the design refinement of the engine.(3)Piston is taken as an example for the statistical analysis of the engine parts' feedback data.For the piston's two fault mileage sequence of a batch of engines within a certain period,the Weibull model is used to analyze the reliability of the piston,and it's failure regularity is investigated.According to the fault mileage sequence of a batch of piston,and the batch of piston's life situations is mastered based on the improved GM(1,1)model life prediction method,and it provides the reference for the maintenance plan arrangement of the engines' after-sales and the design improvement.(4)For the engine reliability and performance evaluation under the condition of trouble-free,and the content of the trouble-free detection are defined,the reliability integrated evaluation of the engine's parts are conducted for the result of the trouble-free detection.The high failure rate of components,such as connecting rod piston assembly and oil pump,are overhauled,the reliability test of the fuel injection pump is carried out,which used for the reliability evaluation of it.The trouble-free detection results shows that the quality and reliability of the engine parts still qualified when the engine derived 200,000 km,although whose performance are varying degrees of decline.