• Title/Summary/Keyword: Automotive noise

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A Study on Sound Quality of Exhaust Tail-pipe Noise of Vehicle (차량 배기토출음 음질분석에 대한 연구)

  • Jung, In Sung;Kim, Hong Ki;Shin, Dong Ho;Lim, Hee Gon;Kim, Sang Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.25 no.2
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    • pp.90-100
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    • 2015
  • Recently, creating a signature sound for a brand has become more important in the automotive industry. It is important to remember that the people inside a vehicle are not the only one, who assess the signature sound, exhaust sound has become a more important factor. Most research has used psycho-acoustic parameter to objectively measure the aesthetic qualities of exhaust sound. However, these results do not parallel the results from subjective analysis. Therefore, this research focused on developing a method for objective quantification to assess the aesthetic qualities of exhaust sound in order to help develop a more appealing signature sound. To do so, the actual exhaust sound was synthesized and subjectively assessed at varied frequencies samples of 30 individuals employed at sejong R&D center. The results were analyzed using the science of harmony scale.

Analysis of Receiving sensitivity according to Contact Surface Change of Transmit-Receiver Ultrasonic Sensor for Fuel Level Measurement in CNG Tank (CNG 탱크 내 연료량 계측을 위한 송·수신 초음파 센서의 접촉면 변경에 따른 수신 감도 분석)

  • Kim, Nam-Wook;Im, Seok-Yeon;Choi, Doo-Seuk
    • Journal of the Korea Convergence Society
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    • v.9 no.4
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    • pp.137-142
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    • 2018
  • This paper is studied, as basic research for measuring the accurate fuel amount of the CNG tank by using the transmit-receive ultrasonic sensor, the receiving sensitivity according to changed the pressure inside the tank and the contact surface of the ultrasonic sensor is analyzed. Measurement was carried out while changing the contact surface of the tank and the sensor to three shapes of Point, Line, and Surface and charging the pressure in the tank at an interval of 1 bar from 0 bar to 5 bar. Experiment results, as the pressure in the tank increased the tendency of the received signal value of the ultrasonic sensor to decrease was confirmed. As the contact area between the tank and the sensor increased, the value of the received signal increased, but the noise also increased. The results of experiment, it is judged that accuracy can be improved by changing the contact surface of the sensor.

A New Method of Health Monitoring for Press Processing Using AE Sensor (음향방출센서를 이용한 프레스공정에서의 새로운 건전성 평가 연구)

  • Jeong, Soeng-Min;Kim, JunYoung;Jeon, Kyung Ho;Hong, SeokMoo;Oh, Jong-Seok
    • Journal of the Korea Convergence Society
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    • v.11 no.11
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    • pp.249-255
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    • 2020
  • This study developed the health monitoring method of press process using the acoustic emission (AE) sensor and high-pass filter. Also, the AE parameters such as ring-down count and peak amplitude are used. Based on this AE signal, the AE parameters were acquired and was utilized to detect the crack of the specimen. Since the defect detection is difficult due to noise and low magnitude of signal, the signal noise and press operation frequency were checked through the Short Time Fourier Transform(STFT) and damped. High-pass Filtering data was applied to AE parameters to select effective parameters. By using this signal processing techniques, the proposed AE parameters could improve the performance of defect detection in the press process.

A Study on 5-Axis Machining of Roller Gear Cam for Rotary Table (로터리테이블용 롤러기어캠의 5-축 가공에 관한 연구)

  • Cho, Hyun-Deog;Park, Jong-Bae;Shin, Yong-Bum;Lee, Kang-Su
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.4
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    • pp.127-134
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    • 2017
  • A rotary table is a positioning device used in metalworking for the multiple axes of machine tools, and the utilization trend is increasing with machining efficiency. In the construction of a rotary table, the core technology is a power transfer unit that drives the table, typically a gear type and a roller gear cam type. As the rollers installed on the turret column have rolling movement on the contact surface of the roller gear cam, the roller gear cam type has the advantage of low wear, high load, and fast driving. Therefore, it is currently being replaced by a roller gear cam type. In this study, we researched a 5-axis machining method for the roller gear cam on a rotary table and a new method of applying double roller gear cam curve to reduce the noise and shock between the roller and the cam surface. We implemented the 5-axis machining process in this study using software to generate NC-code and machined the roller gear cams using a Mazak Integrex-200IV. We found that the roller gear cam and turret were able to identify mutual touch status and the noise from the operation of the roller gear cam was substantially reduced.

An Analysis on the Effect of Application on Vibration Isolation Liner of Elevator Guide Rail Bracket (엘리베이터 가이드 레일 브라켓의 방진라이너 적용효과에 관한 분석)

  • Roh, Seung-Kwon;Kim, Eundo;Oh, Jong-Seok;Cho, Jae-Ung
    • Journal of the Korea Convergence Society
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    • v.10 no.8
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    • pp.145-151
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    • 2019
  • In this study, the effects were analyzed by applying the vibration absorption liner into the guide rail bracket as a part of method to reduce the vibration and noise on the high-rise apartment. As the result of vibration absorption liner performance, it was checked that the level of vibration and noise was reduced around 65.49% in the car side and around 90.05% in the counterweight side. Therefore, the vibration absorption effect by the vibration absorption liner of elevator guide rail bracket became fairly good. In case of the vibration absorption liner application, there was an effect on the reduction of 7.26 to 22.22% at hoistway section area, 3,840,000 to 9,780000 KRW at the cost of material and installation by comparing with the damping beam application. Also, in case of the vibration absorption liner application with light weight instead of damping beam with heavy weight, it was thought to become significant effect at preventing the safety from the accidents on installation site.

Characteristic Analysis of Resistance Spot Welding between Dissimilar Materials of 1.035mm Laminated Vibration Damping Steel with 35㎛ Viscoelastic Resin (35㎛ 점탄성수지가 적용된 1.035mm 제진강판의 이종소재간 저항점용접 특성분석)

  • Bae, Ki-Man;Baek, Jong-Jin;Shin, Chang-Yeul;Kim, Seung-Kyung;Kang, Myungchang
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.12
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    • pp.24-29
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    • 2021
  • Recently, owing to the high demand for eco-friendly cars in the automotive industry, noise and vibrations have become major challenges. The use of laminated damping steel is increasing in response to these demands. Laminated damping steel is primarily used in sound insulation plates. The vibration energy is converted into thermal energy due to the viscoelastic resin being located between two steel sheets and being able to damp the vibrations when an external force, such as, noise or vibration is applied to the steel plate. Laminated damping steel is chiefly applied to dash panels in automotive body parts, and because of its structure, junction technology for bonding with other components is necessary. However, there has not been sufficient research conducted on junctions. In this study, regardless of the electrode shape, in the range of 4.0 ~ 8.0 kA welding current, the same welding force and welding time were applied which were 2.8 kN and 200 m/s (12 cycles) and the tensile shear load and nugget size were analyzed after the resistance spot welding between different materials of laminated damping steel with a thickness of 1.035 mm. The results show that in the range of 5 ~ 8 kA welding current, 1.035 mm laminated damping steel meets the MS181-15 standard, which is the technical standard of Hyundai-Kia Motors.

The Dynamics of Noise and Vibration Engineering Vibrant as ever, for years to come

  • Leuridan, Jan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2010.05a
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    • pp.47-47
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    • 2010
  • Over the past 20 years, constant progress in noise and vibration (NVH) engineering has enabled to constantly advance quality and comfort of operation and use of really any products - from automobiles to aircraft, to all kinds of industrial vehicles and machines - to the extend that for many products, supreme NVH performance has becomes part of its brand image in the market. At the same time, the product innovation agenda in the automotive, aircraft and really many other industries, has been extended very much in recent years by meeting ever more strict environmental regulations. Like in the automotive industry, the drive towards meeting emission and CO2 targets leads to very much accelerated adoption of new powertrain concepts (downsizing of ICE, hybrid-electrical...), and to new vehicle architectures and the application of new materials to reduce weight, which bring new challenges for not only maintaining but further improving NVH performance. This drives for innovation in NVH engineering, so as to succeed in meeting a product brand performance for NVH, while as the same time satisfying eco-constraints. Product innovation has also become increasingly dependent on the adoption of electronics and software, which drives for new solutions for NVH engineering that can be applied for NVH performance optimization of mechatronic products. Finally, relentless pressure to shorten time to market while maintaining overall product quality and reliability, mandates that the practice and solutions for NVH engineering can be optimally applied in all phases of product development. The presentation will first review the afore trends for product and process innovation, and discuss the challenges they represent for NVH engineering. Next, the presentation discusses new solutions for NVH engineering of products, so as to meet target brand values, while at the same time meeting ever more strict eco constraints, and this within a context of increasing adoption of electronics and controls to drive product innovation. NVH being very much defined by system level performance, these solutions implement the approach of "Model Based System Engineering" to increase the impact of system level analysis for NVH in all phases of product development: - At the Concept Phase, to be able to do business case analysis of new product concepts; to arrive at an optimized and robust product architecture (e.g. to hybrid powertrain lay-out, to optimize fuel economy); to enable target cascading, to subsystem and component level. - In Development Phase, to increase realism and productivity of simulation, so as to frontload virtual validation of components and subsystems and to further reduce reliance on physical testing. - During the final System Testing Phase, to enable subsystem testing by a combination of physical testing and simulation: using simulation models to simulate the final integration context when testing a subsystem, enabling to frontload subsystem testing before final system integration is possible. - To interconnect Mechanical, Electronical and Controls engineering, in all phases of development, by supporting model driven controls engineering (MIL, SIL, HIL). Finally, the presentation reviews examples of how LMS is implementing such new applications for NVH engineering with lead customers in Europe, Asia and US, with demonstrated benefits both in terms of shortening development cycles, and/or enabling a simulation based approach to reduce reliance on physical testing.

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Development of high performance and low noise compact centrifugal fan for cooling automotive seats (자동차 시트 쿨링용 고성능·저소음 컴팩트 원심팬 개발)

  • Kim, Jaehyun;Ryu, Seo-Yoon;Cheong, Cheolung;Jang, Donghyeok;An, Mingi
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.6
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    • pp.396-403
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    • 2018
  • In this paper, a high-performance and low-noise centrifugal fan is developed for cooling automotive seats which provide a driver with pleasant driving environment. First, the flow characteristics of the existing fan unit was analyzed using a fan performance tester and CFD (Computational Fluid Dynamics) simulations. The analysis of the predicted flow field indicated vortex flow near the tip of fan hub and stagnation flow on the top of fan hub. Two design points are devised to reduce the vortex flow and the stagnation flow observed in the existing fan unit. First, the cut-off clearance which is the minimum distance between the fan blade and the fan housing is increased to reduce the vortex strength and, as a result, to reduce the overall sound pressure level. Second, the hub shape is more modified to eliminate the stagnation flow. The validity of proposed design is confirmed through the numerical analysis. Finally, a prototype is manufactured with a basis on the numerical analysis result and its improved flow and noise performances are confirmed through the P-Q curves measured by using the Fan Tester and the SPL (Sound Pressure Level) levels measured in the anechoic chamber.

Characteristics of Insertion Loss of Adhesive Tapes to Reduce Noise through Small Opening Hole (미세한 공혈을 통한 소음의 저감을 위한 접착 테이프 별 삽입손실 특성)

  • Yong Thung Cho
    • Composites Research
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    • v.37 no.3
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    • pp.232-237
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    • 2024
  • Adhesive tapes can be conveniently used for various applications by combination of materials requiring diverse mechanical strength and specific adhesives. Duct tape is usually readily available and one of the most widely used adhesive tapes. Duct tapes are composite materials with good mechanical strength consisted of fiber material, which is different from other tapes. In addition, electrical insulation tapes are used for very long period of time for insulating cables, and are also used for reinforcement of mechanical strength and increasing damping of cable in practice. Recently, variety of foam tapes and double-sided tapes are widely used in diverse applications. However, there is no previous work readily available clearly illustrating noise isolation performance of tapes. In present work, noise isolation performance of tapes is presented by measurement of insertion loss of variety of tapes on a small hole. Double-side foam tapes presented the best noise isolation performance among adhesive tapes measured in present work.

Factors affecting recognition of successive impulsive noise (연속성 충격소음의 인지에 관여하는 영향인자)

  • Lee, Jae-Won;Shin, Sung-Hwan
    • The Journal of the Acoustical Society of Korea
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    • v.35 no.3
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    • pp.202-207
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    • 2016
  • Most of noises from cars or home appliances accompany successive impulsive noise due to repeated operation. A human auditory system is able to perceive the successive impulsive noise as either a set of independent noise or amplitude modulated noise according to its occurrence period. This study is to identify main influence factors on understanding of impulsive characteristics and find most appropriate sound quality metrics to express the successive impulsive noise. To do this, the successive impulsive noises were designed and utilized to perform a listening test for identifying conditions where successive impulsive noise can be recognized to have impulsive characteristics. These results were analyzed with sound quality metrics such as loudness, fluctuation strength, and roughness in order to compare the subjective results with the objective results. Consequently, the results revealed that the successive impulsive noise exhibits impulsive characteristics when its occurrence frequency is less than 50 Hz. It was also observed that roughness and fluctuation strength results are not applicable to express the successive impulsive noise because they heavily depend on the amplitude modulation characteristics. On the other hand, loudness results are considered to be useful as an evaluation factor of the successive impulsive noise through the use of loudness limen because it does not depend on the amplitude modulation characteristics.