The Finite Element Analysis Of Coupled Thermal Intensity And Mechanical Strength For An Eight Cylinder Diesel Engine Cylinder Head

Cylinder head is one of the most important and complex parts of the internal combustion engine, and has the most extreme working conditions. In the process of diesel engine work, the flame surface need to bear the high temperature of fuel combustion, at the same time, the cylinder head is also under great pressure. Heat produced by high temperature stress, the explosion pressure in cylinder, bolt pre-tightening force, the valve seat interference force effect on the cylinder head at the same time, making cylinder head working environment very complex, greatly increasing the difficulty of analyzing the cylinder head.In this article the coupling analysis of diesel engine cylinder head was studied. The article mainly includes three parts, the first part is to solve the temperature field and thermal stress of the cylinder head. First of all, using Pro ENGINEER software established the three-dimensional model of diesel engine cylinder head. Then put the model into ANSYS workbench to carry on the grid, set the boundary conditions. Finally, we get the temperature distribution of cylinder head. Comparing the calculation results with the actual temperature measuring point, they are equal within the error range. The second part is coupling analysis of thermal intensity and mechanical strength for cylinder head. First set constraint and force boundary conditions, calculating the distribution of mechanical stress, and then coupling the thermal stress and mechanical stress, calculate the total equivalent stress distribution of cylinder head. Finally, compare and analyze the thermal stress distribution, mechanical stress distribution, coupling stress distribution. In the third part, I try to do some improvement on the cylinder head, the main change area is the bridge of the nose area.The calculation results show that the highest temperature area is mainly in the bridge of the nose area between two exhaust valves. At the same time, the surface temperature of the exhaust duct is higher. Maximum coupling stress appears in the bridge of the nose area between the inlet and exhaust valves, tend to exhaust valve side. Compare the thermal stress distribution, mechanical stress distribution, coupling stress distribution we can find that influence of thermal stress on the cylinder head is the largest. Coupling stress is not simply add up the thermal stress and mechanical stress. Because the eight cylinder diesel engine is at the design stage, the work of this paper can provide necessary reference for cylinder head design and improvement.