Engine Cylinder Head Thermal-Mechanical Fatigue Evaluation Technology and Platform Application

An in-cylinder combustion analysis and a computational fluid dynamics (CFD) coolant flow analysis were performed using AVL FIRE software, which provided the heat transfer boundary conditions (HTBCs) to the temperature field calculation of the cylinder head. Based on the measured material performance parameters such as stress-strain curve under different temperatures and E-N curve, creep, and oxidation data material performance, the cylinder head-gasket-cylinder block finite element analysis (FEA) was performed. According to the temperature field calculation results, the maximum temperature of the cylinder head is 200°C that is within the limit of ALU material. The temperature of the water is more than 21.1°C below the critical burnout point temperature. The high-cycle fatigue (HCF) and thermal-mechanical fatigue (TMF) analysis of the cylinder head were performed by Finite Element Method FATigue (FEMFAT) software. The HCF safety coefficient and TMF life cycle of the cylinder head were calculated, which provided an important guidance for cylinder head structure design of a gasoline engine and diesel engine. The present article establishes a complete simulation and analysis process of cylinder head TMF. The fatigue assessment technology presented in this study is universal that is not only applicable to a cylinder head but also to exhaust manifold, piston, etc. The method has been successfully applied to the diesel engine platform and gasoline engine platform of Jiangling Motors with remarkable impacts.