Studies on an automobile muffler with the acoustic characteristic of low-pass filter and Helmholtz resonator

Yasuda, Takashi; Wu, Chaoqun; Nakagawa, Noritoshi; Nagamura, Kazuteru

doi:10.1016/j.apacoust.2012.06.007

Cited by 57 publications

(25 citation statements)

References 14 publications

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“…Take the Helmholtz resonator (HR) as an example. Although it can achieve a suppression effect in the low-frequency range, its effective silencing band is always too narrow [4,[18][19][20]. In contrast, the expansion-type silencer can achieve a broadband character of noise reduction, yet its silencing frequency is often too high [21,22].…”

Section: Introductionmentioning

confidence: 99%

“…It can be seen from the open public literature that there has been a considerable number of noise reduction methods available for the piping systems, e.g., (i) arrangement of elastic joints, corrugated pipe/bellows, or other components to the piping systems [5][6][7][8]; (ii) installation of a muffler elbow and micro-perforated plates [9,10]; (iii) avoidance of short-radius elbow, sharp bends, and branch pipes in pipeline [11]; (iv) laying damping materials [9]; (v) active control technologies [12][13][14][15]; and installation of pipe mufflers [16][17][18][19], etc. Particularly, installation of a pipe muffler is the most widely used means among these methods.…”

Section: Introductionmentioning

confidence: 99%

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Transmission of Low-Frequency Acoustic Waves in Seawater Piping Systems with Periodical and Adjustable Helmholtz Resonator

Liu

Yang

2017

JMSE

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Abstract:The characteristics of acoustic wave transmitting in a metamaterial-type seawater piping system are studied. The metamaterial pipe, which consists of a uniform pipe with air-water chamber Helmholtz resonators (HRs) mounted periodically along its axial direction, could generate a wide band gap in the low-frequency range, rendering the propagation of low-frequency acoustic waves in the piping system dampened spatially. Increasing the air volume in the Helmholtz chamber would result in a sharply decrease in the central frequency of the resonant gap and an extension in the bandwidth in the beginning, yet very slowly as the air volume is further augmented. Acoustic waves will experience a small amount of energy loss if the acoustic-structure interaction effect is considered. Also, the structure-borne sound will be induced because of the interaction effects. High pressure loadings on the system may bring in a shrink in the band gap; nevertheless, the features of broad band gaps of the system is still be maintained.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transmission of Low-Frequency Acoustic Waves in Seawater Piping Systems with Periodical and Adjustable Helmholtz Resonator

Liu

Yang

2017

JMSE

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“…15,[18][19][20] The sound pressure and the normal particle velocities upstream and downstream of the muffler can be expressed as a transfer matrix with the next equation…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Adaptive muffler based on controlled flow valves

Šteblaj

Čudina

Lipar

et al. 2015

The Journal of the Acoustical Society of America

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An adaptive muffler with a flexible internal structure is considered. Flexibility is achieved using controlled flow valves. The proposed adaptive muffler is able to adapt to changes in engine operating conditions. It consists of a Helmholtz resonator, expansion chamber, and quarter wavelength resonator. Different combinations of the control valves' states at different operating conditions define the main working principle. To control the valve's position, an active noise control approach was used. With the proposed muffler, the transmission loss can be increased by more than 10 dB in the selected frequency range.

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“…A muffler with an interconnecting hole on the tail pipe of automobile muffler was proposed to improve its acoustic performance based on the typical structure. Acoustic performances of the muffler were studied in frequency and time domain [13]. Kore et al [14] analyzed flow field characteristics and acoustic properties of confrontational muffler based on a computational fluid dynamics method.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Flow Field for Automotive Exhaust System Based on Computational Fluid Dynamics

Xu¹,

Zhou²

2014

TOMEJ

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Abstract:In this study, a double mode muffler that can automatically adjust the exhaust resistance according to the engine speed was designed. Based on computational fluid dynamics theory, the governing equation and turbulent equations for numerical simulation of muffler were established. The pressure loss and the internal flow characteristics of the double mode muffler were analyzed by CFD software. The influence of the distance between the main and submuffler on the flow field of exhaust system was researched. In addition, the internal pressure distribution, the turbulence intensity distribution and the velocity vector diagram of the dual mode muffler were also obtained. The pressure loss of double mode muffler is mainly distributed in the area of air mutations. Main silencer plays a leading role in the entire exhaust system. Therefore, the trend of the pressure loss of the exhaust system with the change in the distance between main and auxiliary muffler was also obtained. When the distance between the main and auxiliary silencer changed from 50 mm to 300 mm, the pressure loss of exhaust system muffler first increased and then decreased, and following this, continued to increase. The results will provide a theoretical basis for designing complex exhaust system.

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Studies on an automobile muffler with the acoustic characteristic of low-pass filter and Helmholtz resonator

Cited by 57 publications

References 14 publications

Transmission of Low-Frequency Acoustic Waves in Seawater Piping Systems with Periodical and Adjustable Helmholtz Resonator

Transmission of Low-Frequency Acoustic Waves in Seawater Piping Systems with Periodical and Adjustable Helmholtz Resonator

Adaptive muffler based on controlled flow valves

Analysis of Flow Field for Automotive Exhaust System Based on Computational Fluid Dynamics

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