• 대한기계학회논문집A
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• 제22권2호
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• pp.251-257
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• 1998

Active mufflers have been mainly applied in the large industrial engine due to considerable expense for implementation, but a necessity of development has been increased by the tightened regulation of exhaust noise and the request of high power. In this study, the active muffler prototype for installing in an automobile is designed and constructed. The active muffler is designed so that the primary noise and the control sound are propagated as a plane wave in the outlet. Therefore, the error microphone could be placed outside the high temperature centers of the tail pipe, and the noise radiating to the outside could be reduced in the whole areas around the outlet. For evaluating the control performance of the prototype, the control experiments of band-pass filtered random signal and the modulation of sinusoidal signal which are generated from the primary noise speaker as practical exhaust sound level are implemented. And to investigate the radiation pattern from the outlet of tail pipe and the noise reduction level of points placed adjacent to the outlet, the sound level of adjacent points of thirty is measured.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.242-243
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• 2009

배기토출음은 공회전시 발생하는 소음에 큰 영향을 끼친다. 연비를 높이기 위하여 공회전시 RPM을 낮추면 엔진 점화 주파수가 낮아지며, 이 경우 배기계 위치에 따른 음향학적 공명 주파수와 일치하면 배기 토출음의 크기가 증가한다. 따라서 본 연구에서는 공회전시 배기토출음을 줄이기 위해 소음기의 위치와 각 배기관들의 길이를 최적화하였다. 최적화 결과로써 3 가지 배기계 위치를 얻을 수 있었고, 실제 실험과의 비교를 통하여 최적화된 배기계 위치가 그렇지 않은 배기계 위치에 비하여 소음 저감량이 높은 것을 확인하였다.

• 대한기계학회논문집
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• 제17권7호
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• pp.1833-1840
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• 1993

An efficient vibration analysis method, Component Mode Synthesis(CMS), for an exhaust system with bellows is presented. Analyses are performed for two types of bellows, where characteristics of vibration modes affecting idle shake and interior noise of a vehicle are examined. Also analyzed are the contributions of an exhaust and engine mounting system to the idle shake and interios noise. Comparison between the analysis and test is in good agreement, hence the CMS method is shown to be efficient and valid.

• 한국소음진동공학회논문집
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• 제16권3호
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• pp.233-239
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• 2006

The effect of the joint condition of automotive muffler shell and baffle on radiated noise from muffler shell Is studied. Shell vibration characteristics, especially shift In natural frequency and change in of response amplitude, was identified from finite element analysis and modal tests for various joint conditions between shell and baffle. When there is heat expansion and inner pressure from the exhaust 9as in the muffler with elliptical cross section, the shell expands out, and construct gap with baffles. This gap causes more degrees of freedom of shell vibration and natural frequency shift. By welding the muffler shell to the baffles or using a dual shell muffler, the radiated noise problem could be mitigated supplying more a rigid joint and damping, respectively.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.365-370
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• 2000

This study represents effect to attain to the exhaust gas and the exhaust noise by the inner shapes of automobile muffler, and obtained optimization-data for the inner muffler shapes by the temperature variation of the exhaust gas in muffler. The results of noise show to decrease in order of model-1, 2 and 3 under that the engine speed is 3500 R.P.M and similar values beyond it. CO represented good the model-2 at low engine speed and model-1 at high engine speed. The model-3 was show to tiny variation difference by the variables. HC decrease mostly by increase of the engine speed and expressed low values the model-2 at 3,000 R.P.M and the model-1 at high speed. Wholly, the model-2 expressed stable results. The temperature distributions expressed high distributions by increase of the engine speed, and the model-3 was express most good among three models.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 1998년도 추계 학술발표회 논문집
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• pp.180-192
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• 1998

One of the conventional gas burners has nowadays been used for ladle preheating. As a ladle is one of the open-type furnaces, however, it causes to consume much fuel because of high temperature of exhaust gas from the ladle and the exhaust gas passing through ladle cover makes it worsen a working environment nearby. Therefore, the objective of this study is to develop the recuperative burner system applying for an existing teeming ladle , which is integrated with burner, recuperator and eductor as one of the new type combustion equipments and has many advantages of simple installation, compactness and easy control, especially a great deal of energy saving through the waste heat recovery from exhaust gas. The contents of the study is to design, manufacture of recuperative burner system and to perform its tests experimentally after applying to the teeming ladle in the capacity of 100 ton. Its heat release rate is 1,700,000 kcal/h with COG(Cokes Oven Gas) as fuel gas. The test items are the temperature distribution inside the ladle and the preheated air temperature change depending upon the exhaust gas. Nox, exhaust gas analysis and noise.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.462-467
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• 2001

The present study addresses a computational work of the weak shock wave propagatings inside a silencer system of automobile exhaust pipe. Four different types of the silencer systems and the initial shock wave Mach number $M_s$ of $1.01\sim1.30$ are applied to investigate their effects on the noise reduction and the flow field in a silencer system. The results obtained from the present computational work are compared with the experimental results. The second order total variation diminishing (TVD) scheme is employed to solve the two dimensional, compressible, unsteady, Euler equations. The present computational results predict the experimental results with a quite good accuracy. Of the four silencer systems applied, the most desirable silencer system to reduce the peak pressure at the exit of the exhaust pipe is discussed.

• 한국정밀공학회지
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• 제23권5호
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• pp.137-142
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• 2006

The muffler which reduce the exhaust noise and vibration from engine influence on the engine performance. Recently, exhaust variable valve has set up in the muffler controls the backpressure in the exhaust system. And the backpressure variation according to the exhaust variable valve opening has developed the engine performance. First, the preceding of structural analysis is needed and simulation experiment is requested for the study on the design factor to influence on the operation of the exhaust variable valve. In this study, setting up the various variables according to each composition element needed for the structural analysis of the exhaust variable valve, it is experimented the analysis on the influence of each design factor with the calculation of stress distribution and the displacement to cause about the backpressure for the valve through parameter study.

• 한국소음진동공학회논문집
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• 제12권7호
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• pp.510-519
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• 2002

The present study addresses a computational work of the weak shock wave propagating inside an automobile exhaust muffler. Several different types of the silencer systems are employed to investigate the magnitude of the shock wave during propagating through them. The Initial shock wave Mach number $M_s$ is varied between 1.01 and 1.30, and a normal shock wave is given at the inlet of the silencer systems. The second order total variation diminishing scheme Is employed to solve the two dimensional, compressible, unsteady Euler equations. The present computational results are compared with the previous experimental ones available. The present computations predict the experimental results with a quite good accuracy. Of the four silencer systems applied. the most desirable silencer system to reduce the peak pressure at the exalt of the exhaust pipe is discussed from the Point of view of the engineering design of the silencer systems.

• 소음진동
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• 제9권2호
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• pp.295-301
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• 1999

A Simplified Finite Element Method(FEM) model has been developed for the Exhaust System. For the verification of the usage of the developed model. Natural Frequencies, Mode Shapes and Frequency Response Function have been compared between numerical analysis and experimental result. It shows that the developed numerical model also can be utilized to prove the Stress distribution of the Exhaust System if it can be adopted for the vibration analysis adequately.