Exhaust Hot End Heat Shield Development And Structure Optimization Study

Heat shield is an important part in engine hot side, which can isolate heat resource thenprotect other components in the compartment. Customer has more requirements for heatshield reliability along with increase of engine exhaust temperature and BMEP thanprevious existing parts. To decrease failure rate that is caused by resonance becomes firstpriority. Taking the opportunity of company’s new gasoline engine project, we developednew heat shield for exhaust hot end. In order to avoid the resonance caused by the engineexcitation, enhance heat shield structure stiffness and increase the low order naturalfrequency, we mainly made study on its structure, managed to improve the heat shield’sreliability by taking heat shield’s dynamic characteristics into account. According theanalyze result to optimize the heat shield’s structure. The basic research content andconclusion from this paper are as follows:1. Apply FEA method to calculate and analyze the targeted heat shield’s structuralvibratory parameters like modal shapes and natural frequency etc. Job mainly focus onanalyzing the key parameters in dynamic characteristics result then found out optimizationway.2. Optimized heat shield structure and studied its modal, the result showed obviousenhancement in low frequency modal comparing to baseline heat shield.3. Put optimized prototype in the shaker, made first modal frequency scan andmeasured result. The result showed the optimized design can evidently decrease thepossibility of heat shield failure due to engine vibratory. Comparing the calculation resultsto the test real measurement, the tolerance is small. The calculation result meetsengineering expectations.4. Put prototype in engine, finished engine vibratory endurance test and enginethermal shock test. The heat shields’ validation result is OK after test.The result has been accepted by project team, supplier has launched tooling.