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Tuning a two-chamber muffler for wide-band transmission loss

Munjal, ML (2020) Tuning a two-chamber muffler for wide-band transmission loss. In: International Journal of Acoustics and Vibrations, 25 (2). pp. 248-253.

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Official URL: https://dx.doi.org/10.20855/ijav.2020.25.21666


The design of a muffler with wide-band transmission loss (TL) is a basic requirement for automotive exhaust systems where the exhaust noise is spread over several harmonics of the engine firing frequency. This has led to the concept of a double-tuned expansion chamber. In the present paper, the concept of double-tuning is extended to the two-chamber mufflers. The author's classical Velocity Ratio Algorithm is used here to analyze and design such a muffler. The relevant two-row array is manipulated and simplified to arrive directly at the single most significant term out of the 81 non-dimensional terms constituting the relevant Velocity Ratio. Examination of this single term reveals acoustics of the raised wide-band domes of the TL spectrum of the double-tuned two-chamber (DT2C) muffler vis-a-vis that of an equivalent longer double-tuned single-chamber muffler. Except for a low-frequency trough, its TL curve covers the entire frequency range of interest for control of automotive exhaust noise. It is also shown that the corresponding side-inlet side-outlet (SISO) DT2C muffler configuration has an identically similar wide-band TL spectrum to that of the co-axial muffler configuration. Finally, some guidelines are laid out for designing a DT2C muffler. © 2020 International Institute of Acoustics and Vibrations. All rights reserved.

Item Type: Journal Article
Publication: International Journal of Acoustics and Vibrations
Publisher: International Institute of Acoustics and Vibrations
Additional Information: The copyright of this article belongs to International Institute of Acoustics and Vibrations
Keywords: Exhaust systems (engine); Transmissions; Velocity; Wave transmission, Automotive exhaust; Automotive exhaust system; Expansion chamber; Firing frequency; Frequency ranges; Single-chamber mufflers; Velocity ratio; Wideband transmissions, Mufflers
Department/Centre: Division of Mechanical Sciences > Mechanical Engineering
Date Deposited: 24 Sep 2020 11:41
Last Modified: 24 Sep 2020 11:41
URI: http://eprints.iisc.ac.in/id/eprint/66615

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