• 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.

• 한국자동차공학회논문집
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• 제13권3호
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• pp.10-16
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• 2005

Recently, the international regulations about the exhaust emissions of the motorcycle have been strengthened. The electrically controlled fuel injection type motorcycle has been emphasized to meet with this regulation. However, since the pulsation phenomenon happens in the intake port of the motorcycle because of the characteristic of high speed and the smaller layout than the passenger car, there are many difficulties to select the factor about control parameters needed to develop the ECU system. In this paper, the pulsation values measured from the engine test were compared with the calculated one by WAVE, and it was analyzed the pulsation characteristic according to the driving condition and estimated the mass flow rate. This research showed that the lowest point of the pressure gets lowin the low load and the pulsation of pressure were increased in the high load. Also, the simulation program was verified by showing good prediction of the pulsation and air mass flow rate.

• 한국유체기계학회 논문집
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• 제17권5호
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• pp.54-59
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• 2014

The new high speed combi train prototype project was developed which named HSB. It runs over the speed of 330km/h. As the speed of the train exceeds over 300km/h, due to pressure change in tunnel, aerodynamic problems such as sudden drag increase, severe acoustic noise, passenger discomfort and tunnel pressure sonic boom were occurred. This aerodynamic characteristics in tunnel should be reviewed in early design state to enhance the performance and driving quality of new high speed train. In this paper, the aerodynamic characteristics in tunnel for HSB such as pressure waves in tunnel, a rate of pressure change in cabin and micro pressure wave that cause sonic boom outside tunnel are analyzed by 2D axisymmetric CFD simulations. The results are also compared with the value for ordinary high speed train like the KTX-Sancheon. It is helpful how to design the configuration of HSB train. Finally it shows that the HSB train was well designed in tunnel condition because all values fulfill the criterions on UIC code and Korean national regulations.

• 한국자동차공학회논문집
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• 제25권3호
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• pp.344-349
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• 2017

Suspension noise from under a passenger car is one of the important factors that impact the perceptual quality for drivers. However, it is difficult to validate this by component level testing in the early stage of development, because suspension noise caused by interaction of the related parts has been found at saleable vehicles late during development or at the manufacturing stage, when many customers have already filed for claims. This study proposed a validation testing under research by the DFSS process that enables reproduction of vehicle level noise by component level testing using a shock absorber with the related parts, such as urethane bumper and top mount. This study also developed a compromised test matrix while analyzing the noise factors through experimental design and analysis of variance to determine what factors can affect noise. Based on this study, we expect that the vehicle level and customer claim can be validated during initial development timing by a more reliable component noise validation test.

• 한국철도학회논문집
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• 제13권1호
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• pp.125-130
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• 2010

정부는 수도권 집중화로 인해 야기되는 각종 사회문제들을 해결하기 위해 주변지역의 개발을 통한 서울 집중화를 분산시키려는 노력을 하고 있지만, 수도권의 구먹구구식 철도개발은 주변지역에서 서울중심으로의 접근을 어렵게 만들고 있다. 이에 국내 최초로 완행, 급행열차가 혼용 운행하는 서울9호선 운영계획을 통하여 "주변지역으로부터 서울도심으로의 접근성 향상"과 "다양한 열차 패턴 서비스" 등과 같은 승객서비스질 향상에 대해 생각해 보고자 한다.

• 한국주조공학회지
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• 제16권2호
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• pp.132-140
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• 1996

Both cast and extruded composites of SiC whisker reinforced 6061 Al alloy matrix were fabricated by high pressure infiltration of the alloy melt into the SiC preform and subsequent hot extrusion of the composite ingots. The micro structures, age hardening behavior and mechanical properties have been examined on the both cast and extruded composites of SiCw/6061. The cast composites of SiCw/6061 were obtained in which SiC whiskers were randomly oriented. Hot extrusion of these cast composites lead to alignment of the whisker in the direction of extrusion. Strengthening effect of whisker in the extruded composites is lower than that of the cast composites. The cast composites of SiCw/6061 showed higher thensile strength and lower elongation than extruded composites of SiCw/6061 at all testing temperatures. Lower tensile strength and higher elongation of the extruded composites were attributable to fine grain structures in which grain boundary sliding occruued preferentially at elevated temperatures.

• 한국자동차공학회논문집
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• 제14권1호
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• pp.159-166
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• 2006

Chassis system has a large influence on ride quality, stability and NVH performance of a car. To improve the performance and reduce cost, the development of chassis modular assemblies is emphasized. To develop chassis corner modules, it is necessary to predict the performance of full vehicle motion such as ride, handling performance, NVH characteristics and durability of modules. In this paper, full vehicle test is performed to acquire the road load data of chassis corner module of passenger car. 3-axis simulator modeling are carried out to simulate reaction force analysis and fatigue analysis of new developed modules. Also, real simulator tests to validate performance of new developed modules are performed. We had developed the accelerated durability test procedure of KATECH PG and it is used to test chassis corner modules at laboratory and simulate durability performance. All these results have been provided to module and parts company and make an important role to develop chassis corner modules.

• Journal of Mechanical Science and Technology
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• 제19권6호
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• pp.1321-1328
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• 2005

The characteristics of the diesel spray have affected certain aspects of engine performance, such as the power, fuel consumption, and emissions. Therefore, this study was performed to investigate the effects of various injection parameters. In order to obtain the effect of injection parameters on diesel spray characteristics, the experiment is performed by using a high temperature and pressure chamber. The behaviors of the spray are visualized by using a high speed video camera, spray angle, penetration, and various other things. The results of the experiment are summarized as follows. (1) The correlation of the spray penetration can be expressed as follows. $$0< t $$t_{b} (2) The correlation of the spray angle can be expressed as follows $$T_a=293K\;tan({\theta}/2)=0.59({\rho}a/{\rho}f)^{0.437}$$ $$T_a=473K\;tan({\theta}/2)=0.588({\rho}a/{\rho}f)^{0.404}$$ (3) The measured macro characteristics that include the spray tip penetration and spray angle corresponded with the established correlations.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.151-156
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• 2008

The after 1974 capital region electric railroad is opened to traffic Koraill and Seoul metro adopt each other different power supply method and they operate and they are come. AC 25[kv] method voltage the insulation becomes larger standing distance highly, the case tunnel section which will introduce in the underground segment becomes on a large scale and the cost of construction increases to the city center and the underground segment adoption of DC method was many. To recent times with R-bar (Rigid-bar) introductions change of tunnel section the introduction of AC method came to be easy without in the underground segment. Operates sees in the electric protection where the Seoul metro and the Korail are different each other and, from the dead section segment the interior electric light to put out lights the passenger brings about inconveniently and the civil appeal which demands a power supply method unification occurs, within the company interchange electric railroad brazier safety improvement and maintenance expense curtailment etc. the flaw is original proposal, is a condition which finishes a feasibility study service about the power supply method fringe land. Interchange analysis of the DC electric railway it leads from the present paper and it compares under analyzing being it could be reflected to also the route which is in the process of actual using boil the strong point and a weak point of DC and AC method of the establishment route constructive at the time of and

• 자동차안전학회지
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• 제13권3호
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• pp.69-77
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• 2021

Although accident data from the National Police Agency and insurance companies do not know the vehicle safety, the damage level information can be obtained from the data managed by the bus credit association or the bus company itself. So the accident severity was analyzed based on the side impact accidents using accident repair cost. K-means clustering analysis separated the cost of accident repair into 'minor', 'moderate', 'severe', and 'very severe'. In addition, the side impact accident severity was analyzed by using an ordered logit model. As a result, it is appeared that the longer the repair period, the greater the impact on the severity of the side impact accident. Also, it is appeared that the higher the number of collision points, the greater the impact on the severity of the side impact accident. In addition, oblique collisions of the angle of impact were derived to affect the severity of the accident less than right angle collisions. Finally, the absence of opponent vehicle and large commercial vehicles involved accidents were shown to have less impact on the side impact accident severity than passenger cars.