Thermal-Mechanical Coupling Analysis Of Cylinder Head

Cylinder head is one of the most complicated and important components in internal combustion engine. Cylinder head, the top of piston and liner enclose to form combustion chamber. The explosive force and bolt pre-tightening force act on cylinder head, and its temperature is uneven due to the effect of working medium in combustion chamber and water jacket, so cylinder head suffers high mechanical and thermal stresses, meanwhile high temperature will reduce strength quality of the material, this made the cylinder head injury rate increased significantly, which seriously threaten the safety and reliability of the engine.In this thesis, FEA is employed on the cylinder head of engine. Lots methods are introduced to solve the problem. Established the solid model of cylinder head and cooling water jacket of a certain type of engine; mesh cylinder head using the element type of solid90; established finite element model of cylinder head according to the working characteristic and the finite element theory; mesh the cooling water jacket of cylinder head established the flow model and analyze the temperature and heat transfer coefficient of water jacket wall. The numerical simulation method is used for the cylinder head to the finite element analysis, in the same time, the results of water jacket is used as boundary conditions. The temperature field, thermal stress field and mechanical stress field are calculated separately. On the basis of this, thermal-mechanical stress field and the deformation of the cylinder head are calculated too. Meanwhile, the calculation of the cylinder head by others is compared and shows that the calculation of the cylinder head this time is more reliability. Finally, a way which can reduce the stress and improve the structure of cylinder head is proposed.The strength analyze is of cylinder head is carried out under the thermal mechanical coupling loads. The result shows that the high stress zones exist around the valve guides holes, and it has large deformation prone to fatigue damage, that should make a special consideration in diesel design. And thermal stress field accounts for the major part of thermal-mechanical stress field of the cylinder head. Finally, a simple revised scheme mainly in reducing the thermal stress field is introduced on the calculation.