An Investigation on Transmission Loss for Scooter Muffler by CAE Numerical Method

• Main Authors: Jia-Siou Wu, 吳佳修
• Other Authors: Yuh-Yih Wu
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/t5rcx9

碩士 === 國立臺北科技大學 === 車輛工程系所 === 104 === In Taiwan, one of the major noise pollution sources comes from motorcycles, and the design of mufflers concerns much more with noise producing since the crucial noise legislation. Transmission loss (TL) is an important index for evaluating mufflers performance. In this thesis, Ricardo WAVE software is the tool to analyze TL for the motorcycle muffler. The scooter made from manufacture in Taiwan is our objective to undergo TL simulations. Due to the complex muffler is composed with several simple muffler components, single chamber, double expansion chamber, non-coaxial and short expansion chamber, dissipative perforated silencer, catalyst geometry and sound absorbing materials are simulated and verified at the beginning to ensure the simulation accuracy with WAVE software, and the complex motorcycle muffler is executed verification after that. Finally, exhaust manifold, catalyst converter, sound absorbing material housing and connecting ducts are investigated for the TL effectiveness on motorcycle mufflers. The research results show good simulation accuracy with simple mufflers and objective motorcycle muffler, and there is little differences of TL caused by catalyst converter and exhaust manifold, however, TL at low frequency domain is improved when sound absorbing materials housing is attached to the model. Also, TL is affected at low frequency domain when connecting ducts are added in.