Study On Catalytic Performance Of Gasoline Engine Catalytic Converter

Gasoline direct injection vehicle results in higher fine particle emissions due to its inherent mixture preparation and combustion mechanism.The catalytic gasoline engine particulate filter system is one of the effective measures to solve this problem.Its catalytic converter catalyzes NO in exhaust gas into NO₂with strong oxidation,and oxidizes the particles captured by particle catcher,so as to achieve the purpose of reducing particle emission and continuous operation of catalytic gasoline engine particulate filter system.However,the uneven flow field,low catalytic performance at low temperature and limited catalytic surface area of catalytic converter lead to the degradation of catalytic performance and service life of catalytic converter.Therefore,this paper proposes an improved catalytic converter model for the above phenomenon.The performance of the improved catalytic converter model was determined by numerical simulation with gas uniformity index,pressure drop and NO catalysis as criteria.Since the key parameters have different influence on the performance of the improved catalytic converter,it is necessary to further explore the influence rule of the key parameters on the improved catalytic converter,which is of great significance to improve the purification performance and service life of the catalytic converter and reduce the emission of exhaust pollutants.The main research work of this paper is as follows:（1）Conical variable cell density carrier catalytic converter model was established to solve the problem of uneven internal flow field.Firstly,the flow field,pressure drop and NO concentration field in different models was quantitatively analyzed by comparing with the traditional catalytic converter model,and the improvement degree of the improved catalytic converter performance was determined.Then,the influence of key structural parameters on the performance of the model was explored,and the optimal value and influence degree of key structural parameters were obtained.This research provided important reference value for further improving the structure and optimizing the internal flow field.（2）The model of electric heating variable cell density carrier catalytic converter was established for the phenomenon of low purification performance at low temperature.The model combines the research results of the conical variable cell density carrier catalytic converter and adds an electric heating device to improve the internal flow field and temperature field simultaneously.Firstly,the uniformity of internal flow field and purification performance were quantitatively analyzed to determine its performance by comparing with the traditional catalytic converter model.Then,the influence law of electric power,inlet velocity,inlet temperature and heating time on purification performance and internal temperature field were analyzed to avoid excessive heating and high carrier temperature.This research provides important reference value for reducing the consumption of electric power and improving the thermal stress of carrier.（3）The model of electric heating multi-carrier catalytic converter was established basis of the research of electric heating variable cell density carrier catalytic converter model and adding high cell density carrier,to solve the problem of limited catalytic surface area.The performance of electric heating multi-carrier catalytic converter was analyzed,and the influence of key structural parameters on the purification performance and the temperature field of the carrier was investigated.This paper improves the flow field uniformity,low catalytic performance under low-temperature conditions and limited catalytic surface area of catalytic converter,and improves the catalytic performance and service life of catalytic converter.The research results will provide an important reference value for improving the exhaust pollutant emission control effect of gasoline engines.