Optimization And Research Of Exhaust Manifold Assembly In An Automobile

Vehicles in the test or the normal running of the process, the weight of the engine exhaust manifold assembly in design is too big, it will increase weight of the vehicles, will definitely increase fuel consumption, and contrary to the theme of energy saving and environmental protection, and is not for the lightweight.For the above reasons, this paper optimized the structural of the exhaust manifold, when the fluid properties and the structural properties wore not be dropped. The weight of the final optimized exhaust manifold assembly is reduced about10%.The article by means of fluid-structure coupling simulation of the exhaust manifold assembly, then assembled it to an engine bench to test validation. The main work of this paper is as follows:(1) Simplified the parts which are not very important in the exhaust manifold assembly or the less affected parts of the fluid properties and structural performance. Such as simplified as porous media catalytic converters, threaded flange to ignore some of the chamfer at right angles to transition.(2) Assumed some of solving the problem. Such as fluid flow of the entire simulation area (exhaust manifold inner wall) is assumed for the single-phase. Does not consider the composition of the exhaust, and ignore the impact of the different components of the exhaust gas. Assumes that the exhaust gas does not react chemically, exhaust gas in an instant chemical reaction occurs, but just want to get the inside wall of the heat transfer coefficient, the different components of the exhaust gas heat transfer coefficient is not very big here did not consider the chemistry of the molecules in the exhaust reaction.(3) Fluid-structure coupling on the simulation is able to characterize the performance of the exhaust manifold assembly parameters such as velocity, flow, temperature, stress, strain, deformation and so on. Optimized model before optimization of the model performance is improved through the comparison of these parameters can be determined.(4) Finally, the optimized exhaust manifold assembly is assembled to the engine bench test. Fluid-structure coupling simulation method by comparison of the test parameters on the optimization of the exhaust manifold assembly analysis is feasible.Therefore, the engine exhaust manifold assembly as a whole system to study is feasible. The results show that:the simulation results with the experimental data tend to coincide, the simulation model and simulation methods can be effective in the engine exhaust manifold assembly, it will be shorten design cycles and reduce design costs using this method.