Development of Laboratory Fatigue Testing Apparatus for Automotive Vehicle Engine Valve Simulating Actual Operating Conditions

To improve the efficiency of vehicle engines and reduce greenhouse gas emissions, the operating temperature tends to increase. Thus, it is very important to evaluate the durability performance of engine valves under high-temperature environments. The single supply test method for evaluating the durability performance of an engine valve has been used to minimize real test time and cost, but accurate service life evaluation results cannot be obtained because it does not accurately simulate actual operating conditions. The purpose of this study is to improve the single-supply test method such that it can be performed under various operating conditions to accurately evaluate the durability performance of a valve. An accelerated fatigue testing apparatus was developed based on the analysis of the actual operating conditions. The reliability of the developed fatigue testing apparatus was verified by a performance evaluation test. The fatigue tests were performed on an actual exhaust valve using the developed fatigue testing apparatus. The test results demonstrate that the durability evaluation of a single valve using the developed fatigue testing apparatus enables more accurate life evaluation and fracture mechanism analysis than existing methods.