A Study on the Structural Design and Reliability of Cylinder Head for Vehicle Engines

For reducing the heat rejection and enhancing the cylinder head's performance of enduring the thermal loads, the LHR cylinder head with a ceramic insulating layer is presented in this paper. The ceramic insulating layer, with the thickness of 0.0 mm, 0.7mm, 1.0mm and 1.5mm, is adopted respectively to illustrate the effect of thickness of the ceramic layer on the amount of the heat transfer of the cylinder head. Computed results show that the amount of the heat transfer decrease with the growth of the thickness of the ceramic layer. The three-dimensional FEA is used to calculate the cylinder head's mechanical-thermal comprehensive stresses. According to the FEA results, the stresses of characteristic points of the cylinder head with the heat-insulating layer become larger than those of the non-LHR cylinder head. Then, numerical analyses based on the stress-strength interference are performed to evaluate the cylinder head reliability with different thickness ceramic layer. The results show that all the cylinder heads meet the engineering reliability requirement. The cylinder head with the ceramic layer which thickness is from 0.7mm to 1.5mm reduces the amount of heat transfer from 6.5% to 9.0%.