Analysis Of Internal Flow Field And Vibration Characteristic Of Vehicle Manifold Catalytic Converter

Three-way catalytic conversion of vehicle is the mainstream technology of engine turned purification in exhaust emission control. As countriesâ…£,â…¢, national emission standard practices which equivalent to Europeanâ…¢,â…£, request monitoring and restricting the exhaust gas ingredient of cold before starting the 40s, this makes catalysts should not only has high conversion and long service life, and have more good light-off characteristics. It is difficult that conventional catalyst reach the standard. Manifold catalytic converter as a new structure born in this situation, the advantages of this structure is closer to the engine, it can help catalyst fast light-off and give full play to Catalytic efficiency, so this structure is extensively used in the vehicles which executes Europeâ…¢emission standards and above.Thesis established a three-dimensional model of the manifold catalytic converter, application software FLUENT simulated internal airflow distribution state of velocity field,temperature field and pressure field when flow changes and catalysts in steady state and no chemical reaction. Analysis of the velocity distribution of catalyst surface location before windward of "Stamping half shell mould", "tube plate composite" and conventional catalysts. Finally I compared the analysis results with engine performance test results.Vibration characteristics of manifold catalytic converter also play a vital role in reliability and life, the difference of structure forms and work position makes its vibration characteristics different from other forms of converter, So the thesis analyses this characteristic.Research shows that, the increase of inlet flow makes model pressure loss increased significantly, axial velocity distribution increase of internal airflow, and the flow diametral distribution of uniformity of catalyst surface location before windward reduction. The uniform of air distribution of manifold catalytic converter is better than conventional. Modal analysis got converter first five order natural frequency, vibration model and stress distribution, As the temperature increases,whole structure various order modal value corresponding to the low-frequency direction deflection.