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Acoustic Analysis of Small Engine Catalytic Converters
Technical Paper
2010-32-0022
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Today, catalytic converters are widely used in small engine exhaust systems to reduce pollutants. Besides reducing harmful pollutants, these devices have a significant effect on the acoustical performance and the pressure drop of the engine exhaust system. A catalytic converter is known to have two distinct acoustic effects: the reactive effect originating from the acoustic wave reflections caused by cross-sectional area changes within the unit and the resistive effect which results in the acoustic wave dissipation caused by viscous losses. The pressure drop in the narrow tubes in the catalytic converter element results in frequency dependent resistive effects on the transmitted sound. In this paper the passive acoustic effect which treats the sound attenuation in the catalytic converters has been investigated. An experimental investigation on small engine catalytic converters treated as acoustic two-ports is carried out. A novel test facility, recently set up in TUT for acoustic characterization of exhaust system elements in hot flow conditions is implemented to determine the sound transmission and the pressure drop data across the catalytic converters.
Authors
Citation
Lavrentjev, J. and Rämmal, H., "Acoustic Analysis of Small Engine Catalytic Converters," SAE Technical Paper 2010-32-0022, 2010, https://doi.org/10.4271/2010-32-0022.Also In
References
- Munjal, M.L. Acoustics of ducts and mufflers with application to exhaust and ventilation system design Wiley-Interscience 328 1987
- Peat, K. A first approximation to the effects of mean flow on sound propagation in capillary tubes Journal of Sound and Vibration 175 1994 475 489
- Astley, R.J. Cummings, A. Wave propagation in catalytic converter: formulation of the problem and finite element scheme Journal of Sound and vibration 188 5 1995 635 657
- Dokumaci, E. Sound transmission in narrow pipes with superimposed uniform mean flow and acoustic modeling of automobile catalytic converters Journal of Sound and vibration 182 1995 799 808
- Ih, J.-G. Park, C.M. Kim, H.-J. A model for sound propagation in capillary ducts with mean flow Journal of Sound and Vibration 190 2 1996 163 175
- Dokumaci, E. On transmission of sound in circular and rectangular narrow pipes with superimposed mean flow Journal of sound and vibration 210 3 1998 375 389
- Jeong, S. Kim, T. “CFD Investigation of the 3-Dimensional Unsteady Flow in the Catalytic Converter,” SAE Technical Paper 971025 1997 10.4271/971025
- Wendland, D.W. Sorrell, P.L. Kreucher, J.E. “Sources of Monolith Catalytic Converter Pressure Loss,” SAE Technical Paper 912372 1991 10.4271/912372
- Lavrentjev, J. Rämmal, H. “On Experimental Techniques to Determine Acoustic Performance of Small Exhaust Silencers,” SAE Technical Paper 2009-32-0015 2009 10.4271/2009-32-0015
- Chung, J. Y. Blaser, D. A. Transfer function method for measuring in-duct acoustic properties. I. Theory, II Experiments Journal of Acoustical Society of America 68 3 907 921 1980
- Munjal, M.L. Doige, A.G. Theory of a two source-location method for direct experimental evaluation of the four-pole parameters of an aeroacoustic element Journal of Sound and Vibration 141 323 333 1990