Research On The Acoustic Character And Flow Property Of Catalyst Converter

Exhaust pollution and noise from automotive engine is becoming a serious environment problem in our daily life. In order to satisfy the increasingly stringent emission regulation, the use of catalyst converter is a valid measure. Therefore, we should consider the system performance, the acoustic characteristics, flow property and the diffusing rule of the noise of exhaust. Then we can design the catalyst converter and entire exhaust system more exactly.The analysis of the catalyst converter is carried out by using four terminal networks method and three dimensional acoustic FEM. First of all, the transfer matrix is created by using four terminal networks and then we get the transmission loss curve and impact factor of catalyst converter. The finite element model is constructed in ANSYS, and then imported into SYSNOISE to do the acoustic analysis. The analysis clearly depicts the diffusing process of the noise of exhaust in catalyst converter under the help of sound pressure graph. Also the diffusing rule of low and high frequency sound's transmitting in catalyst converter is pointed out. What's more, the paper discusses the attenuation that occurs in the time when sound passes the catalyst converter, in the end, the TL is got. In the end of this paper, we consider the flow property of catalyst converter. By using FLUENT, the velocity and pressure distribution in the catalyst converter of different inlet cone angle is got, and we get the influence regulation of homogeneity and pressure loss by different inlet cone angle.The study of this paper set up an effective method to predict the acoustic characters and flow property of catalyst converter and provides a theory to optimize the catalyst converter and entire exhaust system design.