• 한국터널지하공간학회 논문집
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• 제12권4호
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• pp.321-328
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• 2010

본 연구에서는 최근 국내 도심지 대심도 지하교통터널 계획과 함께 중요성이 대두되고 있는 터널내 화재 안전 설계에 가장 기본적인 설계 요소인 자동차의 열방출률을 제시하고자 실물화재실험을 실시하였다. 산소소모율법을 적용한 라지스케일칼로리미터를 이용하여 승합차의 열방출률을 측정하였으며, 또한 두 대의 승용차를 인접시켜 터널 정체시 화재 전파 특성을 파악 하였다. 그 결과 승합차의 최대 열방출률은 5.9 MW를 나타내었으며, 일산화탄소는 최대 482 ppm이 방출되었다. 두 대의 승용차의 화재 전파 특성 실험의 경우 화재 발생 후 약 3분 30초 경과부터 인접 승용차에 화재 전파가 시작되어, 15분 경과 후에는 완전한 화재로 발달하였다. 최대 발열량은 9 MW를 나타내었다. 이러한 실물화재실험에서 얻어낸 결과는 향후 수치해석시 중요한 입력 자료로 이용됨과 동시에 터널의 방재설비 설계에 유용하게 적용 될 수 있을 것이다.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2009년도 춘계 종합학술대회 논문집
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• pp.549-558
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• 2009

도로교통공단의 자료에 의하면 2007년 1월 1일부터 2007년 12월 31일까지 1년 동안 우리나라에서 발생한 교통사고는 211,662건이었다. 이로 인하여 6,166명이 사망을 하고 335,906명이 부상을 당한 것으로 집계되었다. 이것은 매일 17명 내외가 사망을 하고 920명이 부상을 당한다고 볼 수 있다. 광주광역시에서도 지난 한 해 8,231건의 교통사고가 발생하여 138명이 사망을 하고 13,533명이 부상을 당한 것으로 집계되었다. 그동안 정부에서는 교통사고를 줄이기 위한 여러 가지 교통정책을 시행하였고 나름대로 진전이 있었으나 아직도 교통후진국이라는 오명을 벗지 못하는 실정이다. 게다가 일반 국민들이 느끼는 교통안전에 대한 무관심도 턱없이 부족하다. 본 연구에서는 광주지방경찰청의 도움을 받아 2008년 봄철에 발생한 교통사고현황과 2009년 3월에 발생한 교통사고현황을 분석하였는데 여기에서는 봄철 교통사고 예방 경찰활동을 살펴보고자 한다. 그런데 천문학적으로는 춘분에서부터 하지까지가 봄이지만, 기상학적으로는 3, 4, 5월을 봄이라 한다. 여기에서 봄철은 3월부터 6월까지를 의미하는데 경찰은 계절의 변화와 교통량을 고려한 경찰활동, 교통약자를 위한 교통 환경 개선과 실질적인 홍보, 보행 중 교통사고와 야간 교통사고 예방 대책, 관광버스 등 단체 여행객 관리, 오토바이와 농기계 운전자를 대상으로 한 경찰활동에 더 많은 노력을 기울여야 한다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2010년도 춘계학술대회 논문집
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• pp.48-48
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• 2010

Sound quality and NVH-issues(Noise, Vibration and Harshness) of vehicles has become very important for car manufacturers. It is interpreted as among the most relevant factors regarding perceived product quality, and is important in gaining market advantage. The general sound quality of vehicles was gradually improved over the years. However, today the development cycles in the automotive industry are constantly reduced to meet the customers' demands and to react quickly to market needs. In addition, new drive and fuel concepts, tightened ecological specifications, increase of vehicle classes and increasing diversification(increasing market for niche vehicles), etc. challenge the acoustic engineers trying to develop a pleasant, adequate, harmonious passenger cabin sound. Another aspect concerns the general pressure for reducing emission and fuel consumption, which lead to vehicle weight reductions through material changes also resulting in new noise and vibration conflicts. Furthermore, in the context of alternative powertrains and engine concepts, the new objective is to detect and implement the vehicle sound, tailored to suit the auditory expectations and needs of the target group. New questions must be answered: What are appropriate sounds for hybrid or electric vehicles? How are new vehicle sounds perceived and judged? How can customer-oriented, client-specific target sounds be determined? Which sounds are needed to fulfil the driving task, and so on? Thus, advanced methods and tools are necessary which cope with the increasing complexity of NVH-problems and conflicts and at the same time which cope with the growing expectations regarding the acoustical comfort. Moreover, it is exceedingly important to have already detailed and reliable information about NVH-issues in early design phases to guarantee high quality standards. This requires the use of sophisticated simulation techniques, which allow for the virtual construction and testing of subsystems and/or the whole car in early development stages. The virtual, testing is very important especially with respect to alternative drive concepts(hybrid cars, electric cars, hydrogen fuel cell cars), where complete new NVH-problems and challenges occur which have to be adequately managed right from the beginning. In this context, it is important to mention that the challenge is that all noise contributions from different sources lead to a harmonious, well-balanced overall sound. The optimization of single sources alone does not automatically result in an ideal overall vehicle sound. The paper highlights modern and innovative NVH measurement technologies as well as presents solutions of recent NVH tasks and challenges. Furthermore, future prospects and developments in the field of automotive acoustics are considered and discussed.

• 한국자동차공학회논문집
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• 제12권2호
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• pp.205-214
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• 2004

This paper presents design concepts, specifications and performances of a newly developed Black Box, the reconstruction analysis tool with the records, and results of validation tests. The Black Box can detect crash accidents automatically, and record the vehicle's motion and driver's maneuvers during a pre-defined time period before and after the accident. The items of the Black Box included the acceleration, yaw-rate, vehicle speed, engine RPM, braking application, steering and several digital inputs for recording driver's maneuvers. To detect the accident-related-crash, it is important to understand characteristics of the crash signal, which are much different from those of normal driving. Therefore, analytical considerations should be taken in designing pre-filtering circuits and selecting appropriate parameters for identifying crash accidents. And, it is necessary to select proper combination of motion sensors and design proper pre-filtering circuits in order to describe the vehicle's motion. The analysis algorithms were developed and implemented which can perform accurate detection of crash accidents, simulating pre-crash trajectories, and calculating parameters for reconstruction analysis of crash accidents. The developed Black Box was installed on passenger cars and several types of validation tests were conducted. Through the tests, the accuracy of the recorded data and usefulness of the analysis tool for reconstruction have been validated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2913-2917
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• 2007

Turbocharger has been widely used in many passenger cars in application with diesel engines because of high power and fuel efficiency. However, flow-induced noise (whoosh or hissing noise) which is generated within the compressor during its operation at marginal surge line can deteriorate noise characteristics. Hissing noise excitation was associated with the generation of turbulence within the turbocharger compressor and radiated through the transmission path in turbocharger system. In this study, a sharp-edged reactive-type muffler was devised and installed in the transmission path to reduce the hissing noise. Acoustic and fluid dynamic characteristics for the muffler were investigated which is related to the unsteadiness of turbulence and pressure in turbocharger system. A transfer matrix method was used to analyze the transmission loss of the muffler. Simple expansion muffler with extended tube of the reactive type is proposed for the reduction of high frequency component noise. Turbulence computation was carried out by a standard ${\kappa}-{\varepsilon}$ model. An optimal design condition of the muffler was obtained by extensive acoustic and fluid dynamic analysis on the engine dynamometer with anechoic chamber. A significant reduction of the hissing noise was achieved at the optimal design of the muffler as compared with the conventional turbocharger system.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 1996년도 학술발표회
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• pp.57-61
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• 1996

Our goal was to make a cost-effective automatic fire extinguishing system for the engine compartment use of automobiles. We designed this system for the engine compartment. This system consists of 1)foam extinguisher, 2)four nozzles, 3)a pipe arrangement, and 4)an extinguishing device which is equipped with a glass bulb as detector. First and foremost, the extinguishing device was carefully designed to keep the system cost to a minimum. Second, a AFFF foam extinguisher was used because no other fire-fighting agents proved effective against fire in the engine compartment. The AFFF(Aqueous Film Forming Foam) agent which was used in the extinguisher is the 3M company's Light Water. We sought, however, to make other foams by using Halon 1301 and Halon alternatives such as HCFC Blend A, HFC-227ea. We selected these alternatives instead of air in order to raise the expansion ratio of the AFFF agent. By these means we discovered that it is possible to increase the expansion ration of the AFFF agent up to 44:1. We then demonstrated that our automatic fire extinguishing system is the most effective and lowest cost-system yet devised for passenger cars.

• 에너지공학
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• 제20권1호
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• pp.54-62
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• 2011

2020년을 목표로 한 국내 중기 온실가스 감축목표가 2009년에 발표된 이후 다양한 온실가스 방안들이 제시되고 있다. 국내 중기 온실가스 감축목표에서는 수송부문의 경우, 현재의 경제성장률을 감안하여 2020년에 약 30% 정도의 배출가스를 줄여야 한다. 수송부문 중에서도 승용차 부문의 주요 감축수단으로서 전기차가 고려되고 있다. 본 연구에서는 손익분기점 분석을 통해 기존 내연기관차와 전기차에 대하여 다양한 시나리오별 분석을 실시하였다. 이를 통해 단기적으로 내연기관차에 비해 경제성 면에서 불리한 전기차에 대한 보조금 정책 도입의 타당성을 제시하였다.

• 한국분무공학회지
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• 제17권4호
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• pp.205-209
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• 2012

This study focused on comparing macroscopic characteristics of DME and diesel fuel experimentally. DME fuel is one of the most promising alternative fuels because of its superiority in atomization characteristic and clearness in terms of exhaust gas compared with existing fossil fuels. In addition, DME fuel has high cetane number so it could be applied to compression ignition engine. However because DME fuel exists in gas phase at room temperature and atmospheric pressure, and it corrodes rubber parts of fuel line, DME fuel is hard to apply to commercial vehicles. To establish knowledge about DME fuel and furthermore, to develop commercial DME vehicles such as passenger cars, many research have been proceeded steadily. The present study, by comparing spray characteristics of DME fuel to those of diesel fuel, improved atomization characteristics in DME were revealed. Injection quantity measurement and spray visualization experiment were progressed and it was revealed that DME fuel shows small injection quantity than that of diesel fuel and axial development of spray in terms of spray tip penetration decreases when DME fuel was injected.

• 자동차안전학회지
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• 제10권3호
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• pp.38-44
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• 2018

Conventional brake system was used for passenger cars and SUV for a long time. However, the high performance brake system has strongly required because of increase of engine power and customer's favorites etc. In this paper, a new high performance brake system for Europe was proposed. For this system, the high performance caliper and disc were newly developed. The superiorities of the developed high performance brake system were verified via heat capacity, hydraulic stiffness, corrosion and harsh braking mode test. Also, the high performance caliper and disc for the light-weight were applied to AL-Alloy and can obtain the weight reduction effect of 2.9 kg per vehicle. Finally, a developed high performance brake system is expected to be used for realization of the high performance at the same platforms.

• 한국소음진동공학회논문집
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• 제20권1호
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• pp.66-73
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• 2010

Vehicles experience the impact due to harsh road conditions. Contact with a barrier on a road induces vehicles to vibrate, which brings about an impact sound. The attenuation of the impact sound is an important issue since passengers may complain about the impact noise. However, the perfect removal of impact noise is not possible as most of impact noise is caused by external conditions. It is thus necessary to make vehicles to possess more desirable sound quality characteristic of impact sound. More research is needed on objective attributes of impact sound; it is not a simple matter since impact noise is transient in nature and has a high level of sound at an instantaneous moment. A new objective attribute of impact noise is designed by using wavelet transform. Wavelet transform is appropriate for the analysis of transient signals such as impact noise. The usefulness of new objective attribute, which is a sound metric, is examined by comparison with the mean subjective rating for real impact noise of passenger cars. The new sound metric has better correlation with the mean subjective rating than already existing sound metrics