An Engine Cooling System

The engine cooling system ensures the engine parts at a certain range working temperature when the engine is working which makes it work well. And the cooling water jacket of the cooling system absorbs the heat directly which is transferred to the air by the circulation. Therefore, whether the structure of the cooling water jacket is reasonable will affect the performance of the cooling system. So, it is essential to make research on the flow field of the water jacket. Nowadays, with the development and improvement of the CFD technology, it has been used in the different aspects of the engine and vehicle research domains more and more. Today, obtaining the flow field of the water jacket by CFD analysis on engine cooling water jacket and validated by the test data has been the important calculation analysis method in the process of the design and optimization of the engine.In this dissertation, the research object is a direct injection gasoline engine. The 3D solid model was created with CATIA which simulated and analyzed with FLUENT software. The flow field and pressure field in the water jacket are obtained and evaluated it. Evaluation of the water jacket flow field whether meets the requirements mentioned above by the CFD results, and checking the flow field to find the reason, then putting forward the modification design. And the improved design was compared with the base results though CFD analysis. At last, the steady thermal analysis of cylinder head was studied by FEA method and a precise temperature distribution in the cylinder head was obtained which help us to evaluate the cooling effect of the water jacket.CFD analysis of the original water jacket shows that there exit stagnation zones in bridge zone of 1st and 2nd cylinders of cooling jacket. In this dissertation, three ways for improving the cooling effect of water jacket were put forward. According to the CFD results comparison, the final improved design which can meet the cooling requirements was determined. Then the temperature field of cylinder head was obtained. Compared with the original model, the highest temperature of cylinder head fire-face of 2nd cylinder reduced by 21℃. And the results testified the cooling effect of the improved design.