Research On The Method Of Engine Auxiliary Accessory Drive System Durability Test

As the higher integrating and complicated structure of present-day vehicle engine, four kinds of durability test in the national standard of china are not meet the requirements of engine durability validation, many of the Chinese independent-brand automobile companies are lack of the experience to self-design engine test plan, the result is that the validation is too much on some parts but not enough on the other parts, that is why there are much parts failure during the customer service although spent huge money and much time during the engine development of those companies. The failure frequency of customer service will be decreased by designing special test method for the failure parts and optimizing the engine test plan. With a new engine developing process of some Chinese independent-brand automobile company, the text designed a test cycle for several failure mode with higher failure frequency during customer service at engine auxiliary accessory drive system and evaluating the validate efficiency.The text analyzed much engine customer servicing record, and made several failure mode with higher failure frequency during customer service at engine auxiliary accessory drive system as the object of test validating. And abstracted city, highway and mixture reference duty cycle from the vehicle road test record with different road condition use to failure calculate. Applied life prediction theory and parts stress measured at rig test to calculate the failure ratio of each failure mode at different operation condition of the city reference duty cycle and made the operation condition with bigger failure ratio as the operation condition of auxiliary accessory drive system durability test cycle.Evaluated the test cycle validate efficiency with two methods, the first method is that made a new test plan by adding the test cycle to the original test plan of the developing engine, applied the AVL load matrix method to compared the reliability of each failure mode after validating with the original and new test plan. The second method is that comparing the sample amount with difference test cycle at the multi-sample reliability test for predicate product reliability, it needs less engine sample with the auxiliary accessory drive system durability test cycle than the durability test cycle with best validation efficiency to auxiliary accessory drive system in the original test plan.The developing engine development process has applied the auxiliary accessory drive system durability test cycle, and a total 600 hrs rig test with this test cycle has finished, it indicated that this test cycle is availability.