Structure Design And Optimization Of Manifold-type Catalytic Converter

With the continuous development of the automotive industry, automotive production and sales continue increasing sharply, which result in air pollution, based on environmental pollution problems, many countries publish increasingly stringent vehicle emissions regulations, in the same time many automotive manufacturers attach importance to catalytic converter research increasingly. Conventional catalytic converter is now unable to meet the EURO VI emission standards, especially in the automotive cold start-up phase, it can not effectively control vehicle emissions, so people start changing chemical composition of the catalyst and the structure of the catalytic converter, which can decrease ignition time of catalytic converter in the car cold start-up phase and improve the conversion rate of motor vehicle exhaust. This paper focuses on study of the catalytic converter structure design, CAEsoftware is used to numerical simulation of manifold-type catalytic converter, according to result, manifold-type catalytic converter is optimized.Based on the spatial location of the cylinder head and the catalytic converter outlet flange surface, combined with the design theory of the exhaust manifold, the structure of manifold-type catalytic converter could be designed, the specific size of the various components could be determined, and UG software is used to complete its three-dimensional modeling. STAR-CCM+software is used to simulate the flow field of manifold-type catalytic converter, according to the calculation results, the impact of branch piping layout and the shape of front cover for the design specifications could be studied detailedly. and then the pipe line is changed to reduce flow pressure loss of the branch pipe, every flow pressure loss of the branch pipe could be more close. In the same time it also can makes the gas which outflows branch pipe sweeps slightly to the oxygen sensor, which causes oxygen sensor can accurately probe to the concentration of oxygen ions; and the shape of the front end cover is optimized to reduce the gas flow separation from wall surfaces, which causes the gas spread to increase the speed uniformity coefficient of the front surface. Secondly, based on the principle of fluid-structure interaction, the same intake method is used to analyze steady-state temperature field and thermal stress of manifold-type catalytic converter, calculation results show that structure design of the improved manifold-type catalytic converter is reasonable.This article completes the design and analysis of the manifold catalytic converter, further experiment should be completed. This work on the manifold-type catalytic converter could provide theoretical basis for the structural design of manifold-type catalytic converter.