• Title/Summary/Keyword: noise reducing

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Exhaust Noise Control of Marine Diesel Engine Using Hybrid Silencer (조합형 소음기를 이용한 박용 디젤 엔진 배기 소음 제어)

  • Lee, Tae-Kyoung;Joo, Won-Ho;Bae, Jong-Gug
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.7
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    • pp.679-684
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    • 2009
  • Low frequency exhaust noise of marine diesel engine is one of the most important noise sources in vessels. However, conventional absorptive silencers are ineffective to control exhaust noise because of low absorption in the low frequency range. In the paper, exhaust noise control of marine diesel engine was studied by using the hybrid silencer, which was composed of virtually divided array of concentric hole-cavity resonators and conventional absorptive silencer. A series of tests including field tests were performed to investigate the acoustic performance of the hybrid silencer. Consequently, its high performance of 5${\sim}$10 dB noise reduction in the low frequency range was confirmed and it is expected to be very helpful in reducing the exhaust noise of marine diesel engine.

Experimental Evaluation of Buzz, Squeak and Rattle Noise of Vehicle Doors and Its Prevention (자동차 도어의 BSR 소음의 실험적 평가와 개선)

  • Shin, Su-Hyun;Jung, Sung-Soo;Cheong, Cheol-Ung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.12
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    • pp.1217-1222
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    • 2007
  • With recent advance in automotive noise control engineering reducing major sound sources in the vehicle, customers perceive Buzz, Squeak and Rattle (BSR) as one of important indicators of vehicle quality and durability. As the long-term goal, we expect to establish the integrated design cycle for the reduction of the BSR noise in the early stage of vehicle development. which consist of design, prediction and evaluation procedures. This is possible only with great bulk of experimental data for BSR noise. In this paper, BSR noise is experimentally identified for vehicle doors, which have been traditionally considered as one of main sources of BSR noise. Based on this result, we proposed systematic method for the prevention of BSR noise in the vehicle doors.

A Study on the Reduction of Simulation Errors in the Prediction of Military Aircraft Noise (군용항공기 소음예측시 오차저감에 관한 연구)

  • Kim, Mi-Jin;Lee, Byung-Chan
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.3 s.120
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    • pp.249-256
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    • 2007
  • Aircraft noise is a serious problem to inhabitants near airports. INM is one of programs for determining the predicted noise impact in the vicinity of airports. It has been widely used for engineers to evaluate aircraft noise. However it is difficult to predict aircraft noise in case of lack of exact INM input data. The exact informations about a fighter plane are not known well for a security problem. This study presents methods of reducing errors between measurement and simulation when the exact INM input data is not known. Especially we adjusted the thrust force of aircraft engine and reduced the error.

Improvement in rise time and robustness of AC servomotor (AC servo motor 제어시 rise time 과 강인성 개선)

  • 정광조;임선종
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.446-450
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    • 1991
  • PID controller is popular but have defect inversing following reference input and noise elimination. Therefor, this paper focus on reducing rise time and robustness against noise. The result that is simulated with feedforward method and sliding mode show that rise time decrease and robustness increase.

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