Jun Hong, Baotong Li*, Yubao Chen and Huei Peng
The Journal of Mechanical Science and Technology, vol. 25, no. 10, pp.2607-2614, 2011

Abstract : The engine cylinder head is one of the most critical components in an automotive powertrain system. Yet, it has the most complicated mechanical structure coupled with a sophisticated combustion process. This study attempts to develop a concrete and practical procedure for the optimal design of the engine cylinder head. First, a simplified topological model composed of beam, shell and membrane elements is developed to simulate the real cylinder head. With this model, the finite element method can be easily and economically employed to study the load-bearing mechanism of the cylinder head under actual engine operation conditions. After characterizing the stress/strain behavior of all the key components through parametric analysis, a new optimization criterion is developed based on Lagrange conditions. This criterion provides an opportunity to represent the ideal ‘balanced point’ among the main design parameters of the cylinder head in terms of weight distribution of the key components. Finally, the optimization of the cylinder head structure is implemented successfully based on these findings. Compared to the optimization results from commercial software, the proposed approach is able to produce a much better solution in respect to both the convergence speed and the final value of the objective function.

Keyword : Engine; Cylinder head; Optimal design; Topological model; Parametric structure characterization; Weight distribution criterion