Effect of Catalyst and Filter to Transmission loss

• Main Authors: Jin-Yu Gu, 古晉宇
• Other Authors: C. I Chu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/82160551685493900896

碩士 === 逢甲大學 === 機械工程學所 === 92 === This research focuses on the effect of the transmission loss of catalyst and filter. There are not many researches on this aspect in past, because it is hard to calculate the transmission loss inside muffler. It is hard to calculate the transmission loss, if the components of catalyst and filter exist in the muffler. However, since the program of direct-mixed body BEM appears, the program solves the complex problem of sound field inside muffler. In this research, we regard the catalyst and filter as the second media of outside layer of air. When the sound wave is transferring in the muffler, parts of heat energy will disappear, because the friction will make the energy transfer to heat energy. Therefore, the sound absorption works. We use the Boundary element method to be the tool of calculator, and use experiments to test and verify. In the aspect of sound absorption, the result proves that the catalyst and filter indeed have the effect of sound absorption. When we add the catalyst and filter in the muffler of Type-Band Type-C, the experiments and analysis increase 2 dB compared with the result of before add the transmission loss of catalyst and filter. Beside the liable proof program, the research proves that the catalyst filter have effects of transmission loss.