This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Transmission Loss Analysis of an Exhaust System of Combustion Engines. Part I: Measurements
ISSN: 0148-7191, e-ISSN: 2688-3627
Published November 16, 2004 by SAE International in United States
Annotation ability available
Aiming to solve pass by noise issues, where the exhaust system is the main source, a bench test was built. It was based on an impedance tube method to measure the transmission loss of exhaust systems of vehicle combustion engines. The test bench reduces time on investigation of acoustic performance of exhausts systems and does not depend on weather conditions. The results were used to compare several proposals under investigation before assembling on the vehicle and also to give a comparable metric for validating numerical simulation modeling and analysis procedure. This paper describes the problems involved in the construction of the evaluation system. Three types of noise source were evaluated, considering pink and white noise. Four methods for calculating the transmission loss were compared against easiness of implementation and robustness of results: the decomposition method, a modification of the decomposition method proposed by Chung, the two-sources method and the two-loads method. A single expansion chamber was used to validate the bench test and also to start the CAE correlation procedure. A deeper view on the problems regarding the implementation of CAE procedure and correlation with bench test will be discussed on part II of this work.
CitationGuedes, R., Botteon, A., Ferraz, F., Junior, L. et al., "Transmission Loss Analysis of an Exhaust System of Combustion Engines. Part I: Measurements," SAE Technical Paper 2004-01-3404, 2004, https://doi.org/10.4271/2004-01-3404.
- Acústica - Medição do ruído emitido por veículos rodoviários automotores em aceleração - Método de engenharia 2002
- 1998 Acoustics -- Measurement of noise emitted by accelerating road vehicles -- Engineering method
- VAN DER LINDEN, P. J. G. FLESZAR, A. R. Combining vehicle and test-bed diagnosis information to guide vehicle development for pass-by noise SAE technical papers 2001
- Standard test method for impedance and absorption of acoustical materials using a tube, two microphones and a digital frequency analysis system
- CHUNG, J. Y. BLASER, D. A. Transfer function method of measuring in-duct acoustic properties. I. Theory. II. Experiment JASA 68 3 1980
- TAO, Z. SEYBERT, A. F. A review of current techniques for measuring muffler transmission loss Noise and vibration conference and exhibition. SAE technical papers Traverse City, Michigan, USA May 2003
- MUNJAL, M. L. Acoustics of ducts and mufflers New York Willey-Interscience 1987
- KIMURA, M. R. M. 1995 Medição e simulação acústica de silenciadores Mechanical Engineering Department Federal University of Santa Catarina Florianópolis, SC, Brazil
- Analysis of concentric tube resonators with perforations: comparison between Sysnoise prediction and results of J.W. Sullivan & M.J. Crocker - LMS International notes
- MUNJAL, M. L. 1987 Acoustics of Ducts and Mufflers 1st New York John Wiley & Sons
- Li, J. Computational and Experimental Study on Transmission Loss of Automotive Exhaust Muffler System SAE paper 2003-01-1648