패널의 진동을 이용한 머플러의 투과 손실 개선

장진웅,이진우 대한기계학회 2022 大韓機械學會論文集A Vol.46 No.12

In this study, the local thickness of the panel surrounding a muffler was optimized to improve the transmission loss of the muffler within the desired frequency range, and the results were verified using experiments. A rectangular muffler made of acrylic and aluminum, one side of which can be regarded as a vibrating panel and its other sides as rigid walls, was designed and used as the analysis model. An optimal design problem for the muffler was formulated considering that a change in the panel's vibration characteristics highly influences the acoustic characteristics of the expansion chamber constituting the muffler. The objective function was declared by reflecting a target noise frequency range and applying the vibro-acoustic coupling effect while using the local thicknesses of the panel as design variables. The muffler's optimal design problem was solved using an optimization algorithm, and a discussion conducted on the results with regard to vibro-acoustic coupling. Finally, the effectiveness of the designed muffler was verified. The results of this study show that the effective application of the vibro-acoustic coupling effect can significantly increase the noise reduction performance of a muffler. 본 논문에서는, 원하는 주파수 대역에서 머플러의 투과 손실을 개선하기 위해 머플러를 둘러싸고있는 패널의 두께를 국부적으로 최적화하고, 설계한 결과를 실험으로 검증한다. 한 면은 진동하는 패널로, 나머지 면은 강체벽으로 간주할 수 있는 직육면체 형상의 머플러를 해석 모델로 선정한다. 이 패널의 진동 특성 변화는 머플러를 구성하는 확장방의 음향 특성에 강하게 영향을 준다는 사실을 고려하여 머플러 최적 설계 문제를 정식화 한다. 머플러의 목표 소음 주파수 대역과 진동-음향 연성 효과를 반영하여 목적 함수를 구성하고, 패널의 국부적인 두께를 설계 변수로 선정한다. 최적화 알고리즘을 이용하여 머플러 최적 설계 문제의 해를 구하고, 최적화 결과에 대한 진동-음향학적인 고찰을 진행한다. 최종 설계된 머플러는 아크릴과 알루미늄으로 제작하여 검증 실험을 수행한다. 이 연구 결과는 진동-음향 연성 효과를 효과적으로 이용하면 머플러의 소음 저감 성능을 개선시킬 수 있다는 사실을 입증한다.

목표 음향 특성을 갖는 머플러 내부 설계

민재홍,오기승,이종겸,박상영,이경훈,이진우 대한기계학회 2019 大韓機械學會論文集A Vol.43 No.6

In this paper, a design procedure to modify an acoustic system according to target acoustic characteristics is proposed and is applied to a design problem of a muffler for an automobile. The transmission loss values of a muffler mounted on an exhaust system should be changed considering the results of the sound quality evaluation test. The inlet and outlet of the muffler do not coincide with each other, and it has three holey baffles and three holey tubes. The effects of each part on the transmission loss curve are investigated in the frequency range of interest, and the dominant parts are selected for design. Two size optimization problems are formulated and are sequentially solved using a commercial finite element analysis program. The transmission loss curve of the obtained optimal muffler is compared with a target transmission loss curve, and an acoustical experiment on a manufactured muffler is carried out. 본 논문에서는 목표 음향 특성을 갖도록 음향 시스템을 변경하는 설계 절차를 제시하고, 자동차용 머플러 설계 문제에 적용한다. 차량의 배기계에 장착되는 머플러는 음질 평가 결과에 따라 특정 주파수 대역의 투과 손실 값을 적절히 변경하는 노력이 필요하다. 사용된 머플러는 입구와 출구가 일치하지 않고, 다수의 구멍이 존재하는 배플과 삽입관을 각각 3개씩 갖고 있다. 각 구성 요소의 변화에 따른 투과 손실 곡선의 변화를 살펴보는 선행 연구를 수행하여, 관심 주파수 대역의 음향 특성에 큰 영향을 미치는 설계 변수를 선별한다. 두 개의 치수 최적 설계 문제를 정식화하고, 상용 유한 요소 프로그램을 사용하여 순차적으로 최적해를 구한다. 이렇게 최적 설계된 머플러의 투과 손실 곡선과 목표 투과 손실 곡선을 비교하고, 제작한 머플러에 대한 음향 실험을 수행한다.

양모와 라텍스 결합소재를 이용한 머플러디자인 연구

김형주(Hyung Joo Kim) 한국디자인문화학회 2011 한국디자인문화학회지 Vol.17 No.2

현대 섬유패션산업에서 고부가가치를 실현하기 위해서는 디자인 개발과 소재에서의 차별화가 필요하며 소비자의 생리적인 요구뿐만 아니라 감각적인 요구에도 부응할 수 있는 소재의 개발과 패션에의 적용이 필요하다. 특히 개성화, 고급화, 다양화 되어가고 있는 소비자의 기호변화에 부응하기 위한 감성과 디자인을 중심으로 차별화된 섬유제품의 개발이 시급하다고 할 수 있다. 감성소재 개발은 종류가 다른 섬유를 혼방, 교직하는 방법이나 기존 소재의 용도를 달리하여 이용하는 방법이 있으나 새롭고 다양한 효과를 얻을 수 있는 효율적인 방법은 특성이 다른 소재를 코팅 또는 결합하는 방법이 될 수 있겠다. 이러한 시대적 요구에 부응하기 위해 본 연구에서는 양모섬유에 천연 액상라텍스(Liquid Latex)를 날염하여 새롭고 흥미로운 결합소재를 제작하고, 이를 이용하여 독창적인 외관의 머플러디자인을 연구하는데 그 목적을 두었다. 연구방법으로는 국·내외 전문서적과 인터넷 보털사이트(Internet Vortal Site)1), 선행연구논문, 학술발표논문을 참고하여 이론적 고찰을 하였다. 그리고 머플러를 디자인하기에 앞서 양모와 라텍스 결합소재의 실험을 통해 패션소재로서의 적합성 여부를 판정하여, 실용성 있는 머플러디자인을 연구·개발하였다. 연구 범위는 양모의 구조와 축융성, 라텍스의 물성을 고찰하고, 양모섬유가 물, 알칼리, 열과 적당한 압력에 축융되는 특성과 라텍스의 경화되는 성질을 응용하여 결합소재를 제작한 후, 한국의류시험연구원(KATRI)에 시험들을 의뢰하여 시료분석 및 측정을 하였다. 이러한 실험을 통한 분석을 토대로 양모섬유와 라텍스의 상이한 두 소재의 결합을 통한 머플러디자인을 연구·제시하였으며 다음과 같은 결론을 도출할 수 있었다. 첫째, 양모섬유에 라텍스 용액을 살짝 표면 도포한 후 축융 처리하면 양모소재의 축융성과 라텍스의 경화되는 물성을 통해 자연스러운 주름의 텍스처(Texture)가 돋보이는 머플러를 디자인 할 수 있었다. 둘째, 양모섬유에 라텍스를 도포한 후 1시간 이상의 축융 처리로 섬유소재를 제작한다면 환경변화와 세탁요인에 대하여 뛰어난 치수안정성을 가진 머플러 디자인 제작이 가능하였다. 셋째, 액상 라텍스는 도포하는 방법으로 디자인을 표현하므로 바탕 섬유소재의 종류와 두께에 관계없이 다양하고 창의적인 표현이 가능하였다. 넷째, 라텍스는 염료나 안료와의 결합도 수월하여 의도하는 모든 색상표현이 가능하였고, 접착력도 뛰어나 다른 섬유와의 결합을 통한 다양한 소재 개발이 가능해 보였다. 본 연구는 양모섬유와 라텍스 결합에 의한 텍스처의 조형 표현을 중심으로 새로운 소재를 개발함으로써 섬유패션산업에 중요한 연구 자료가 될 수 있도록 하였다. 이와 같이 다양한 결합소재의 지속적인 연구를 통해 국제적으로 경쟁력 있는 패션디자인상품 개발 방향을 제시할 수 있을 것으로 기대된다. To make higher value-added realized in the modern textile fashion industry, differentiation in terms of design development and materials is required, and it is needed to develop materials and apply them to fashion that are likely to meet not only consumers` physiological demand but their sensuous demand. Especially, it seems urgent to develop differentiated textile products by focusing on sensibility and designs likely to catch up with the change of consumers` preferences being more individualized, gentrified and diversified. For the development of sensuous materials, there are methods of mixed spinning or mixture with different textiles or methods of using the existing materials in different ways, but the most efficient one to bring about new and various effects can be a method of coating or combining of materials with different characteristics. In order to satisfy the various needs projected in this very era, this research focused on the production of a new and interesting combined material by printing natural liquefied latex onto a wool textile. This in turn is utilized to carry out the purpose of this very research in creating a muffler design with ingenious exterior. Regarding the research method, contents such as technical publications, Internet Vortal Site, academic publications, and literature from both South Korea and other countries have been considered for theoretical conceptions. In addition, prior to the creation of a muffler design, an experiment of the latex combined material and wool is carried out in order to decide the suitability of the material as a fashion material to further investigate and develop a practical muffler design. The research will cover the structure and felting property of wool as well as to study the property of latex. By utilizing the hardening property of a latex and milling characteristic due from the characteristics of wool textile fulled by water, alkali, heat and the right amount of pressure to make a combined material. In the end, sample analysis and measurement are carried out by requesting Korea Apparel Testing & Research Institute for experiments. Based on the results and analysis from the experiments, a muffler design that combines the two different materials, wool textile and latex, is researches and suggested to further draw following results. First of all, after lightly spreading the liquefied latex onto the surface of wool textile, milling processing will result in a natural wrinkle textured muffler design due to the hardening property of latex as well as the felting property of wool material. Second of all, if a textile material is produced with more than an hour of milling process after the spreading of latex onto the surface of wool textile, it is possible to produce a muffler design that possess an excellent dimensional stability regarding washing factors and environmental changes. Third of all, in case of a liquefied latex, it expresses the design by the spreading method, thus it is possible to express various and creative ideas regardless of the type and the thickness of the background textile material. Last of all, it was possible to express all kinds of intended colors because a latex is easy in combining it with either dye or pigment. At the same time, its adhesiveness is excellent and therefore it would be possible to develop various materials by combining it with other textiles. This study is designed to provide research data important for the textile fashion industry by developing a new material while focusing on the molding expression of texture by the combination of wool fabric with latex. Through such constant researches as this one on various combined materials, it is expected to suggest directivity for the development of fashion design products more competitive internationally.

소형 자동차의 머플러 형상에 따른 유동에 관한 융합 연구

최계광,조재웅 한국융합학회 2021 한국융합학회논문지 Vol.12 No.1

본 연구에서는 자동차 머플러의 형상별 유동해석을 수행하여 가장 유동성을 증가할 수 있는 설계 모델을 찾는 데에 있다. Model B가 최대 압력이 비교적 가장 작게 나오고 Model C가 가장 크게 나왔다. 자동차의 머플러 형상에 따른 최고의 유동 속도를 비교하면 Model A가 비교적 입구 및 출구에서의 유동의 흐름이 원활했다. 그러나 Model B는 머플러 내에서의 유동 속도는 크지만 출구에서는 유동 속도가 가장 적어져서 유동의 효율성은 떨어져 보인다. 머플 러의 형상에 따른 유동 해석 결과에 의하여 좀 더 유동이 원활한 모델을 찾음으로서 머플러를 효율적으로 설계할 수 있다고 사료된다. 본 연구 결과를 이용하면 실제 실험을 하지 않아도 소형 자동차의 머플러 형상에 따른 유동을 조사할 수 있다. 또한 소형 자동차의 머플러의 미적인 융합 설계에 도움이 될 수 있다고 보인다. The flow analysis by each configuration of automotive muffler in this study was carried out. And it aims at finding the design model that can increase the flow property best. It is shown that model B has the lowest maximum pressure and model C has the largest. Compared with the best flow rate according to the shape of the automotive muffler, model A had the comparatively smooth flow stream at the entrance and exit. However, model B has the largest flow rate in the muffler but the least flow rate in the exit, making it look less efficient. By the flow analysis result according to the muffler configuration, it is thought to design the muffler effectively by looking for the model with more smooth flow. The result of this study can be used to investigate the flow according to the configuration of small car muffler without actual test. It also seems to be helpful in the aesthetic convergent design of small car muffler.

PIV에 의한 반능동형 머플러 내부의 유동특성에 관한 연구

김동현(Donghyun Kim),박경석(Kyoungsuk Park),허형석(Hyungseok Heo),박세종(Sejong Park),한창평(Changpyung Han),손성만(Sungman Son) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5

Recently, the performance development of the exhaust system of a car is very important. The most important part of parts that constructing the exhaust system of a car is a muffler. The muffler reducing the exhaust noise from the engine influence on the engine performance directly. The inner parts of the muffler construct with the baffle and perforated pipes and so on. In the recent study, the study to design the semi-active muffler sensing the exhaust gas pressure controlling the back pressure variably with a variable valve progress activity. So that the inner parts of the muffler show the complicated turbulent flow phenomena because of pulsatile flow from the engine and the structural properties and so on. The qualitative and quantitative analysis about the turbulent flow phenomena of the inner parts of the muffler is required gradually. In this study, to analysis the flow field of the inner parts of the muffler, analysis results with the PIV measurement to be able to analysis the variable change of the time and the space. Therefore, try to show the design variables to need to design the inner parts of a muffler of a car.

배기음 최적튜닝을 위한 머플러 튜닝키트에 관한 연구

박기철(Ki Chul Park),김동선(Dong Sun Kim),김익훈(Ik Hoon Kim),육지헌(Ji Heon Yook) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

The exhaust muffler, one of the important parts in the vehicle, is the essential device to reduce engine-induced noise. But it is very difficult to achieve listenable exhaust sound and it takes much time to tune inner structures of mufflers. In order to achieve harmonious exhaust sound quality, it is necessary to comprehend the sound characteristics of various inner structures (tube length, baffle location, etc) inside mufflers. So, this study proposes muffler tuning kit as a practical new method possible to reduce tuning time and test sample numbers. First, we select muffler outer shape and volume as a original base muffler. Second, we design detail components of muffler(case, end plate-front/rear, tubes-inlet/middle/outlet and baffles). The tuning kit is designed to be possible to assemble, dissemble and change any components of different dimensions. Third we make tuning kit based on the preliminary detail design and compared exhaust noise in the engine bench with the original base muffler sample for NVH correlation. As a result, exhaust noise of tuning kit is well matched with that of original base muffler sample. So we are expecting the tuning kit to be used to reduce tuning time and test samples of mufflers when developing new vehicle.

전달경로의 차이를 이용한 새로운 차량용 능동 머플러의 개발

황요하(Hwang, Yo-Ha),이종민(Lee, Jong-Min),김승종(Kim, Seung-Jong) 한국소음진동공학회 2002 한국소음진동공학회 논문집 Vol.12 No.5

A new active muffler system has been developed and its superior performance on both noise reduction and engine torque increase is demonstrated with experiment. Main characteristic of the proposed muffler system is the use of destructive interference by transmission path difference of divided exhaust pipes to reduce major exhaust noise components thereby overcoming problems of other active exhaust noise control methods. The exhaust pipe is divided into two sections and joined again downstream. One divided pipe has a sliding mechanism to vary its length, which is controlled to make half wavelength transmission path difference for the major engine rpm frequency. In this system one divided pipe is used to control major rpm frequency and its Harmonics and another pipe is used to control noise component double the frequency of rpm. An after-market tuning muffler, which has very simple internal structure and minimal back pressure, is also installed to remove remaining wideband noise. To make the system to be small enough to be practical, conventional muffler is also installed and used in low rpm range and active muffler is only employed in high rpm range. Noise reduction of the proposed system is comparable to conventional passive muffler. The engine dynamo test has proved the proposed system can recover almost all the torque lost by conventional muffler.

A Numerical Study with FSI Mode on the Characteristics of Pressure Fluctuation and Discharge Valve Motion in Rotary Compressors with Single and Dual Muffler

Hee Moon Chae,김창녕 한국정밀공학회 2010 International Journal of Precision Engineering and Vol.11 No.4

Rotary compressors in air-conditioners have been considered for the efficiency enhancement and noise reduction. To perceive the characteristics of noise in a rotary compressor, the features of discharge valve motion and pressure fluctuation in compressors have to be examined. This study has been conducted to investigate the characteristics of discharge valve motion and pressure fluctuation in association with refrigerant flow in rotary compressors with single and dual muffler. The current study has been performed with the FSI mode since the discharge valve oscillates in association with periodic compression of refrigerants in the compressors. For the case of dual muffler, it has been observed that the displacement of discharge valve is smaller than that in the case of single muffler since the compressor with dual muffler has larger inner resistance to the refrigerant flow than that in the case of single muffler. Also, the standard deviation and the energy spectrum of the pressure fluctuation with the dual muffler are smaller than those with the single muffler. Therefore, the use of the dual muffler is expected to contribute to the noise reduction. To the contrary, it has been found that the efficiency of the compressor with dual muffler is smaller with the diminution of volume flow rate compared to the case of single muffler. This study may supply a basis for the design of rotary compressors with higher efficiency and lower noise.

자동차용 환상형 소음기에 관한 실험적 연구

김병삼,김우진 한국기계기술학회 2023 한국기계기술학회지 Vol.25 No.6

Internal combustion engine is the main source of environmental pollutants and therefore advanced technology is required to reduce harmful elements from the exhaust gases all over the world. Especially, when the exhaust gas is released from the automotive muffler, exhaust noise has many bad influence on the surrounding environment. In order to reduce the exhaust noise, it is necessary that automotive muffler must be designed for best exhaust efficiency. The sound insulation room was installed for the analysis of an acoustics characteristics of the noise from automotive muffler, in this study. Exhaust gas noise, noise distribution characteristics, pressure and temperature of exhaust gas were investigated with the change of annulus temperature of air cooled annulus automotive muffler and cooled annulus automotive muffler. The following results were obtained with this study. From the frequency analysis of automotive muffler, high noise distribution was observed in the range 100~2000Hz. It means that the noise in this range has an dominate influence for the overall noise. Noise reduction of automotive muffler was affected by the temperature of annulus. It is caused the result that the high temperature and pressure of exhaust gas are changed lower by the drop of annulus temperature. The tendencies of noise, the temperature and pressure of exhaust gas are similar to the performance curve of engine. Exhaust gas pressure is determined by the r.p.m. of engine and affected by the cooling performance of automotive muffler.

머플러의 유체 유동 및 연성 변형 해석

조재웅(Jae-Ung Cho),한문식(Moon-Sik Han) 한국기계가공학회 2010 한국기계가공학회지 Vol.9 No.1

Car muffler has the role to form the exhaust gas from high temperature-pressure to lower level and reduce the generated noise. Because of this role, its durability decrease as deformation by heat is occurred. This study is to analyze the flow of exhaust gas inside muffler and its coupled thermal deformation with 3-D modeling and ANSYS. There is the fastest flow at the exit of muffler with the maximum velocity of 54 ㎧. And the maximum deformation or equivalent stress is shown at this model respectively as 0.00435 ㎜ or 3414.4 ㎫ by the influence of heat and pressure at part of intersection with inlet and body of muffler.