CAE Approach to Reduce Cylinder Head Development Cycle Time

Traditional engine cylinder head design processes using Finite Element Analysis (FEA) are often iterative and unsystematic. After initial FEA, Computer Aided Design (CAD) changes are implemented to improve initial results, and subsequent designs are explored to identify improved proposals using ad hoc criteria. This iterative process is complex and time-consuming, reducing the likelihood of finding an acceptable, highly durable design. To improve the traditional product development approach, a unique application of FEA techniques that involves morphing and sub modelling is presented in this paper. The study identifies a methodology to assess water jacket durability early in the design process to understand possible design solutions, reducing High Cycle Fatigue (HCF) risks. Critical HCF areas typically occur on the water jacket in the vicinity of the combustion dome, due to the tensile stresses induced by the thermal and combustion pressure loading. Critical areas are identified by zones that don’t meet acceptable fatigue safety factor targets. These regions are then modified with morphing and sub-modelling methods to quickly improve the water jacket design by raising the fatigue safety factors in the targeted regions. Uniqueness of using Damage approach along with safety factor to meet design target of dyno hours, helped to optimize design. Implementation of this methodology reduces required design iterations and hence the engine development time needed to arrive at highly durable cylinder head water jacket designs.