• Title, Summary, Keyword: Engine Noise

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Performance Optimization of Electromagnetic Active Engine Mount (전자식 능동 엔진 마운트 성능 최적화)

  • Kim, Won-Kyu;Kim, Youn-Su;Lee, Wan-Chul;Hong, Sung-Woo;Kim, Gui-Han
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.514-519
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    • 2011
  • Recently, the interest in technologies for a highly efficient powertrain, i.e. a variable displacement engine or a light weight car body, to improve the fuel efficiency of automobile saving the environment has been increased. However this trend deteriorates NVH performance of a vehicle and the use of a conventional engine mounting system becomes unsatisfactory. In order to solve this dilemma, an active engine mounting system that could isolate or cancel out vibrations occurred at the powertrain was suggested. In this paper, In order to optimize the electromagnetic active engine mount performance, the actuator of the engine mount through FEM analysis and optimal design, noise and elastomer testing of the prototype through the optimal design of actuators for the electromagnetic active engine mount on the impact of the performance improvement is verified.

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The Study on the Noise Contributing Factors Extraction of the Passenger Diesel Engine(I) (승용 디젤엔진 소음 기여인자 추출에 관한 연구(I))

  • Kim, Sung-Hun;Kwon, Yong-Jun;Ko, Pil-Kyu;Jung, Yeon-Uk;Lim, Ock-Taeck
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.3
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    • pp.90-98
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    • 2011
  • Noises from diesel engine are the major issues for noise pollution as well as affect customers' purchasing needs to vehicles powered by diesel engine. This study investigates to screen-out main factors that contribute to noises from diesel engine using VGT 2000cc engine developed recently. Changes of fuel temperature, intake temperature and the presence of three way catalyst don't affect the 'Engine Radiation Noise' and the solely three way catalyst influence on the 'Tail Pipe Noise'. Especially, there are no effects of the presence of three way catalyst on torque, which is main subject that should be considered in secondary study.

A Quantitative Separation Method of Structure and Air Borne Sound Power from the Enclosure (차음구조물의 방사음향파워로부터 고체 및 공기전파음향파워의 정량적인 분리법)

  • 김의간;강동림
    • Journal of Advanced Marine Engineering and Technology
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    • v.16 no.5
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    • pp.85-96
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    • 1992
  • Engine enclosures are widely adopted to reduce the noise emission in various fields of application. The radiated noise, which is due to the vibration of enclosure's outer surface, is composed of two kinds of sound power with different path of propagation. One is the 'structure-borne sound power' which stems from the engine's vibratory force applied to the structure of enclosure through the mounting parts of engine etc., while the other is the 'air-borne sound power' which is originated by the sound power radiated from the engine surface to the inner space of enclosure that should excite the vibration of enclosure from inside. In order to get a most efficient engine enclosure is required a profound consideration upon the above structure-borne and air-borne noise, since the guiding principle of countermeasure for each noise is quite different. The controlling of input vibration and its isolation are major subject for the structure-borne sound power and the specifications of absorbing member and damping panels are the major interests for the air-borne sound power. Hence it seems very efficient to separate the total sound power into two categories with a great accuracy when one think of further reduction of engine noise from the exciting enclosure, however, its separating methods have not been made clear for many years. Then author proposes a new practical separation method of two propagation path's contribution to the total radiation sound power for the enclosure under the engine operating condition.

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Noise Control for 4,500 TED Container Carrier (4,500 TEU 컨테이너 운반선의 소음 제어)

  • 김동해;임도형
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1313-1316
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    • 2001
  • Generally, container carrier has larger engine than other commercial vessels and the engine casing is located in accommodation space. Therefore, the noise levels of cabins and engine room could be exceeded the specified noise limits and might be an annoyance to crews, and which can result in poor ship quality. Main subject of this study is to predict noise levels of the 4,500 TED container carrier by statistical energy analysis method in order to comply with contracted noise limits and to compare with the measured values. Additionally, through the contribution analysis of noise sources to each cabins, and appropriate countermeasures are proposed and the reduction effect of each noise control measure is studied by the analysis method. This study will contribute to reduce the noise levels of similar vessel.

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Analysis of Rattle Noise of a Direct Engine-driven PTO Driveline of Tractors (엔진 직결식 트랙터 PTO 전동 라인의 치타음 분석)

  • Park, Y.J.;Kim, K.U.
    • Journal of Biosystems Engineering
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    • v.31 no.1
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    • pp.1-8
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    • 2006
  • This study was conducted to identify the characteristics of PTO rattle noise of a direct engine-PTO driveline for agricultural tractors. In order to reduce production costs of agricultural tractors, a direct engine-PTO driveline was recently introduced to the tractors produced in Korea. This simplified drive line reduced a number of gears and counter shafts in previous one. However, it caused a severe rattle noise under an idle condition, which was perceived as intolerable by many tractor operators. PTO rattle noise was measured at two locations: one 3 em apart radially from the centerline of the PTO shaft and another 100 em apart backward from the PTO end and 160 em high from the ground. Characteristics of the rattle was analyzed using the data measured near the PTO shaft. It was found that the period of rattle noise was same as the explosion stroke of engine and its peak level was about 123 dB (A) with PTO engaged at an idle engine speed of 880 rpm. As the engine speed increased, the rattle noise decreased. The frequency band of the rattle was 0.5-2.0 kHz and the frequency of peak sound pressure was 1.4 kHz. When compared the rattle noise between the locally produced and imported tractors of the same type of PTO driveline, the former generated louder rattle noise than the imported one by 7 dB (A). It was suggested that the rattle noise of local tractors must be reduced at least by 7 dB (A) to meet the international level.

An Experimental Study(I) on the Noise Emission Characteristics of Motor Vehicles Using Sound Intensity Measurement Method -A Case of Engine and Exhaust Noise- (음향 인텐시티 측정법을 이용한 자동차의 소음방사특성에 관한 실험적 연구 I -엔진 및 배기계 부위소음을 중심으로-)

  • 양관섭;유남구;박병전;김영완
    • Journal of KSNVE
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    • v.6 no.6
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    • pp.843-849
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    • 1996
  • Locations and emission characteristics of noise source of motor vehicles are great important factors to control the road traffic noise in effective ways. From results of this study on emission characteristics of engine and exhaust noise, we could find that every noise emission of different kind of vehicles has smilar pattern. The main emission locations of engine noise for the front of vehicle became the space between the road surface and bottom of the body and radiator grill, and for the side of vehicle became the space between the road surface and bottom nearby the front wheel. In case of exhaust noise of passenger-car and light truck, all the highest sound intensity level located near surface of road. But it is hard to conclude the height of noise source of driving vehicles with only results of this study. So further studies are needed to check the emission characteristics of noise.

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An Engine Structure-Borne Noise Analysis by Finite Element Method (유한요소법에 의한엔진 구조소음 해석)

  • 안상호;김주연;김규철
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.1
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    • pp.122-133
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    • 1998
  • This paper presents the static analysis, the modal analysis and the forced vibration analysis on engine structures to find out the structure-borne noise sources by finite element method. The deformation of engine structures under the maximum combu- stion gas force was calculated through the static analysis, and the resonance possibilities were predicted by the modal analysis which ascertains mode shapes and the corresponding frequencies of engine global and its major noise sources in engine surfaces were investigated with the forced vibration analysis by means of finding the transfer mobilities on engine surfaces due to the piston impact and the velocity levels due to the combustion in consideration of oil film stiffness and damping coefficients. Finally, the direction of engine structure-borne noise reduction can be estabilished by the above-mentioned analysis procedure and the reduction effect of cost on proto-type engine build-up is expected.

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Design of automotive engine cooling fan and study on noise reduction through modification of system (자동차용 냉각팬의 설계와 시스템 개선을 통한 저소음화 연구)

  • 김병주;강상규;김규영;이덕주;이재영;이덕호;신동수
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.196-201
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    • 2003
  • Axial fans are widely used for automotive engine cooling device due to their ability to produce high flow rate to keep engine cool. At the same time, the noise generated by these fans causes one of the most serious problems. Especially, engine cooling fan noise in idle condition of a car is noticeable. Therefore, the high efficient and low-noise fan is seriously needed. When a new fan system is designed, system resistance and non-uniform inflow are the key factors to get the high performance and low noise fan system. In this study, experimental study on the fan and system was carried out and brought a successful result of performance and noise from a designed fan. And through the modification of the fan system, the fan produced more flow rate and became less noisy.

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Design of Automotive Engine Cooling Fan and Study on Noise Reduction through Modification of System (자동차용 냉각홴의 설계와 시스템 개선을 통한 저소음화 연구)

  • 김병주;강상규;김규영;이재영;이덕호;신동수
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.11
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    • pp.1107-1114
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    • 2004
  • Axial fans are widely used for automotive engine cooling device due to their ability to produce high flow rate to keep engine cool. At the same time, the noise generated by these fans causes one of the most serious problems. Especially, engine cooling fan noise in idle condition of a car is noticeable. Therefore. the high efficient and low-noise fan is seriously needed. When a new fan system is designed, system resistance and non-uniform inflow are the key factors to get the high performance and low noise fan system. In this study, aerodynamic and acoustic calculations are carried out on the automotive cooling fan and system. Effects of various design parameters are studied through the free wake analysis and experiments. Better performance and noise characteristic are obtained for the new design fan using the methodology. Furthermore through the modification of the fan system geometry parameters, the fan system produce more flow rate and become less noisy.

Noise Control of an Air Intake system for a Four-Cylinder Engine (4기통 엔진의 흡기계 소음제어)

  • 김태정;홍상범
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.77-83
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    • 1996
  • Noise control process of an air intake system for a four-cylinder automotive engine is described. The objective of the process is reduction of induction noise without losing engine performance and changing package layout. The theory and feasibility for noise control elements are also discussed. In general, four-cylinder engines generate a lower frequency induction noise around 80-150 Hz (2400-4500 rpm) and firing frequency, valve impact noise are the main sources. In this paper, the most problematic noise source is identified first and better position of air inlet is selected between inside-fender and out-of-fender layouts. Secondly, the possible noise control approach and CAE analysis results are compared to those from speaker excitation tests. Finally, the effect of the controlled intake system after the installation to an automobile is presented.

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