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In recent years, Turbo-charged GDI technology is more and more widely used, which can meet the high demand of the engine performance and efficiency, but the resulting reliability and NVH issues also need to be paid attention to [1]. Traditional NVH performance improvement is mostly based on the experience design and repeatable test, which lead to longer development period, high cost, and also ineffective results. NVH performance simulations play more important role in engine vibration and noise prediction along with the development of the simulation technology[2][3]. The force response analysis is usually used to evaluate the NVH performance of the engine structure under the standard excitation. However, dynamic analysis of the crank train, valve train, and piston can be carried out based on the AVL software family, also the vibration and airborne noise of whole engine can be predicted directly at different speed and load [4].

Nowadays high thermal efficiency engine is the mainstream of the gasoline engine development, and the control of the design period is strict, which lead to the cylinder head design become more and more difficult. How to get the optimal design of cylinder head quickly is an important research topic by design professionals in the current, which not only meets the performance requirements, but also guarantees the requirement of reliability. The sub-model method is high efficient and high precision in solving the complex problem of stress and strain, which widely used in truss, road, bridge and large container. Using this technology in the local structure optimization of the cylinder head, will shorten the cycle of structure optimization significantly, and get the optimal design of cylinder head quickly. In this paper, Firstly, the cylinder head global FE model was set up.

In order to reduce emissions, size and manufacturing cost, integrated exhaust manifold become popular in gasoline engine, especially in three-cylinder engine. Moreover, due to shorter length, lighter weight, and less component connections, the exhaust manifold and hot end durability will improve apparently. In this work, an advanced cylinder head with integrated exhaust manifold is adopted in a three-cylinder turbo engine. Because of this integration characteristic, the gas retain in cylinder head longer and the temperature reach higher level than normal cylinder head, which will cause thermal fatigue failure more easily. To validate the exhaust manifold and hot end durability, series simulation and test validation work have been done. Firstly, overall steady state and transient temperature simulation was done for global model. For turbocharger, in order to simulate the outlet turbulent flow and 3d rotation, a code was compiled to define this 3d rotation.