American Journal of Vehicle Design
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American Journal of Vehicle Design. 2014, 2(1), 22-31
DOI: 10.12691/ajvd-2-1-4
Open AccessArticle

Numerical Assessment and Shape Optimization of Dissipative Muffler and Its Effect on I.C. Engine Acoustic Performance

Sabry Allam1,

1Automotive Technology Department, Faculty of Industrial Education, Helwan University, Cairo, Egypt

Pub. Date: November 27, 2014

Cite this paper:
Sabry Allam. Numerical Assessment and Shape Optimization of Dissipative Muffler and Its Effect on I.C. Engine Acoustic Performance. American Journal of Vehicle Design. 2014; 2(1):22-31. doi: 10.12691/ajvd-2-1-4


Passive mufflers are widely employed to reduce industrial and domestic ventilation noise as well as vehicle exhaust noise. Their basic geometry is formed by a simple expansion chamber and the performance is controlled by using complex geometries or by adding porous materials inside the chamber. However, when a clean absorbent system is desirable or when the muffler must support high air flux, it is not possible to add those fibrous materials and the use of micro perforated panels (MPP) as another alternative to improve the acoustic performance become important. The purpose of this work is not only to optimize the acoustic performance of low cost simple geometry mufflers using MPP but also to find the best shape design under a limited space constraint aiming at improving the acoustic performance of automotive engines. In this paper, on the basis of plane wave theory, the four-port system matrix for two wave guides coupled via a MPP tube is derived and used to compute the two-port transfer matrix for an expansion chamber muffler with a MPP tube. Two different procedures to optimize the muffler acoustic performance; the acoustical based and the numerical based methods are presented under the same boundary conditions at a targeted frequency of 1500 Hz. Different methods to improve the MPP wall impedance are presented and compared. New optimized muffler is proposed and used to study the acoustic performance of four-cylinder diesel engine and compared with its performance using the existing straight through resonator muffler. It has been shown that the new optimized muffler reduces the engine noise around 6 dB(A), and also reduces the brake specific fuel consumption of the same engine about 8 percent at same operating conditions.

MPP numerical assessment dissipative muffler shape optimization engine noise pressure drop fuel consumption

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[1]  J. M. Egana, J. Diaz, J. Vinolas, Active control of low-frequency broadband air conditioning duct noise, Noise Control Eng. 51 (5) (2003) 292-299.
[2]  H. J. Lee, Y. C. Park, C. Lee, D. H. Youn, Fast active noise control algorithm for car exhaust noise control, Electron. Lett. 36 (14) (2000) 1250-1251.
[3]  M. L. Munjal, Acoustics of ducts and mufflers, Chichester: John Wiley, 1987.
[4]  L. J. Yeh, Y.-C. Chang, M.-C. Chiu, Shape optimal design on double-chamber mufflers using simulated annealing and a genetic algorithm, Turkish J. Eng. Env. Sci. 29 (2005) 207-224.
[5]  Ver, I.L., Beranek, L.L, Noise and vibration control engineering, Second Edition, John Wiley&Sons, Inc., 2006.
[6]  David A. Bies and Colin H. Hansen “Engineering Noise Control -Theory and Practice” 2003, Spon Press 11 New Fetter Lane, London EC4P 4EE.
[7]  D.-Y, Maa. Potential of microperforated panel absorber, Journal of Acoustical Society of America, Vol.104, no.5, July 1998.
[8]  D.-Y, Maa, “Theory and design of micro perforated-panel sound-absorbing construction” Sci. Sin. XVIII, 55-71 (1975).
[9]  D-Y, Maa “Microperforated panel at high sound intensity” Proc. internoise 94 (Yokohama,1994).
[10]  Allam S. and Abom M., 2011, ‘‘A New Type of Muffler Based on Micro perforated Tubes’’. Journal of Vibration and Acoustics’’, ASME Journal of Vibration and Acoustics, 133.
[11]  Allam, S., and Åbom, M., 2008, “Experimental Characterization of Acoustic Liners With Extended Reaction,” The 14th AIAA/CEAS Conference 2008, p. 3074.
[12]  Guo, Y., Allam, S., and Åbom, M., 2008, “Micro-Perforated Plates for Vehicle Application,” The 37th International Congress and Exposition on Noise Con- trol Engineering, INTER-NOISE 2008, Shanghai, China, Oct. 26-29.
[13]  J. Liu, D. W. Herrin and A. F. Seybert “Application of Micro-Perforated Panels to Attenuate Noise in a Duct SAE 2007-01-2196.
[14]  Chang, Y. C., Yeh, L. J., and Chiu, M. C., “Numerical studies on constrained venting system with side inlet/outlet mufflers by GA optimization,” Acta Acustica united with Acustica, Vol. 90, No. 1-1, pp. 1-11 (2004).
[15]  Chang, Y. C., Yeh, L. J., and Chiu, M. C., “Shape optimization on double- chamber mufflers using genetic algorithm, Proceedings ImechE Part C: Journal of Mechanical Engineering Science, Vol. 10, pp. 31-42 (2005).
[16]  Yeh, L. J., Chang, Y. C., and Chiu, M. C., “Numerical studies on constrained venting system with reactive mufflers by GA optimization,” International Journal for Numerical Methods in Engineering, Vol. 65, pp. 1165-1185 (2006).
[17]  Min-Chie Chiu “SHAPE OPTIMIZATION OF ONE-CHAMBER MUFFLERS WITH REVERSE-FLOW DUCTS USING A GENETIC ALGORITHM”, Journal of Marine Science and Technology, Vol. 18, No. 1, pp. 12-23 (2010).
[18]  Sabry Allam “Shape Optimization of Reactive Muffler and Its Effect on I.C. Engine Acous-tic Performance” The 16th ICSV 2009 - July 5-9, Krakow, Poland.
[19]  Sabry Allam “Shape Optimization of Complex Multi-Chamber Muffler” The 17th ICSV 2010 - July 17-21, Cairo, Egypt.
[20]  Patidar, A., Prasad, S., Gupta, U., and Subbarao, M., “Commercial Vehicles Muffler Volume Optimization using CFD Simulation,” SAE Technical Paper 2014-01-2440, 2014.
[21]  Allam, S., and Åbom, M., 2005, “Acoustic Modelling and Testing of Diesel Particulate Filters,” J. Sound Vib., 288, pp. 255-273.
[22]  COMSOL Multiphysics 3.5, User’s Guide Copyright 1994-2010.
[23]  L. Cremer, “Theory regarding the attenuation of sound transmitted by air in a rectangular duct with an absorbing wall, and the maximum attenuation constant produced during this process.” 1953 Acustica 3, 249-263. (In German.).
[24]  B. J. Tester, “The Optimization of Modal Sound Attenuation in Ducts, in the Absence of Mean Flow, Journal of Sound and Vibration , 1973, 27(4), 477-513.
[25]  B.J.Tester, “The propagation and attenuation of sound in lined ducts containing uniform or plug flow, Journal of Sound and Vibration, 1973, 28(2), 151-203.
[26]  M. Åbom, “Measurement of the scattering matrix of acoustical two-ports,” Journal of Mechanical System and Signal Processing 5 (1991) 89-104.
[27]  Lief, N. “International standards for acoustics and noise control.” J. Noise Control Engng, March–April 1989, 32(2), 67-72.
[28]  International Standard IEC 651:1979 Sound Le_el Meters, 1979 (International Electrotechnical Commission, Geneva, Switzerland).
[29]  ANSI SI. 1-1994 “American National Standard Acoustical Terminology, 1994 (American National Standards Institute, Acoustical Society of America, New York).