Study On Integrated Design And Analysis System Of Motorcycle Muffler

When a muffler is to be designed or improved, it is of greatly signification to predict its performances rapidly and to provide reliable reference and direction for further analysis. So it has practical value to design an integrated system that can meet these requirements as well as offering some useful documents and experiences of muffler design.Transfer matrix method (TMM) based on propagation of plane waves is a mature theory. It has been successfully applied to muffler performance analysis. Although the calculation accuracy of TMM is relatively poor at high frequency intervals, the use of TMM is simple and convenient. It makes calculation rapidly and processing program easily. So it is helpful to use TMM to analyze muffler performance in order to accelerate design speed at the beginning of muffler analysis and design.In this paper, an integrated system of analysis and design for motorcycle muffler (Integrated System) is designed. The system is based on TMM and the theory of fluid mechanics. It is designed by synthetically using MATLAB, UG, VC++ tools and taking account of characteristics of motorcycle mufflers. Integrated System contains the following units: acoustic performance analysis module, pressure loss calculation module, optimization design module, automatic modeling module and supporting modules. Through Integrated System, users can get the acoustic performance and pressure loss of muffler just by simple operations, such as choosing basic acoustic element to build muffler model and inputting parameters for each element. Furthermore, optimization calculation of muffler structure can improve the performance of muffler while the main structure unchanged. Automatic modeling module can generate muffler 3D model automatically just by some simple characteristics setting. It provides convenience for the follow-up muffler analysis. Integrated System can provide some useful information, such as national standard library about noise control, for muffler design.Finally, the mufflers of ATV250 and one 150cc motorcycle were analyzed by Integrated System. Integrated system had results of transmission loss curve, which was basically consistent with the calculating results by finite element method, thus the accuracy of Integrated System verified. Pressure loss was also gotten after calculation. Furthermore, a modified case of ATV250 was taken as an example for optimizing and automatically model, and expected results was gained. At the same time, the paper introduced the detail of how to use the system.The realization of integrated system supplies a convenient tool for exhaust noise control of motorcycle.