• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.547-554
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• 2013

The fuel storage vessel installed in CNG vehicles can be largely divided into 3 parts: head, cylinder, and dome. Studies of the cylinder and dome parts have already been performed, but sufficient design data is not available about the head part. Therefore, expert field engineers heavily depend upon trial-and-error methods. Therefore, FE analysis is performed to review the hot spinning process for forming the head part of the CNG vessel using the Arbitrary Lagrangian-Eulerian (ALE) method. The effects of forming factors on the load were analyzed. The values of the factors were chosen to avoid defects in the head part and buckling, and the forming feasibility of the head part was investigated. Furthermore, a bursting test was performed to evaluate the safety of the storage vessel.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.378-383
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• 2005

This experimental study presents the results of the cooling performance test of a $CO_2$ heat pump system for fuel cell vehicles. The experimental facility provides the cool ing and heating environment for cabin and heat releasing component. The test loop is designed to target the cooling capacity of 5kW and its coefficient of performance (COP) of 2.2. The cooling performance of the heat pump system is strongly dependent on the refrigerant charge and the degree of superheat. We carried out basic experiments to obtain optimum refrigerant charge and the degree of superheat level at the internal heat exchanger outlet. The heat pump system for fuel cell vehicles is different from that of engine-driven vehicles, where the former has an electricity-driven compressor and the latter has the belt-driven (engine-driven) compressor. In the fuel cell vehicle, the compressor speed is an independent operating parameter and it is controlled to meet the cooling/heating loads. Experiments were carried out at cooling mode with respect to the compressor speed and the incoming outdoor air speed. The results obtained in this study can provide the fundamental cool ing performance data using the $CO_2$ heat pump system for fuel cell vehicles.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.5
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• pp.2005-2010
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• 2011

Since recently exhaust gas regulation for a non-road small engine as well as commercial vehicle engine has been enforced, a carburettor of a small engine should be replaced by an electronic fuel injection system. In this study, the spray characteristics of the 400cc gasoline small engine injector has been experimentally analyzed. Based on the experimental results, suitable injector for the small engine has been selected. Through the test rig measuring spray mass distribution, fuel distribution characteristics of 3 hole- and 6 hole-injector has been analyzed. Through the visualization equipment, injector spray angle, penetration length and spray width have been measured and analyzed. Considering spray characteristics and stability, 6 hole-injector is selected for the 400cc gasoline small engine.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.3
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• pp.301-306
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• 2010

DME(Di-Methyl Ehter, $CH_3OCH$) is currently attracting worldwide attention due to its environmentally friendly characteristics. Until now it was researched as a major alternative fuel of diesel automobile because it is a clean fuel producing low soot. Therefore, in this study, in order to investigate the effect of DME mixing on number density and size of soot particle, DME has been mixed in opposed-flow ethylene diffusion flame with the mixture ratios 5%, 14% and 30%. A laser extinction/scattering technique has been adopted to measure the volume fraction, number density, and size of soot particles. The experimental results showed that the soot concentration of mixture flames with the mixture ratios 5% and 14% produces soot more, even though that of 30% was decreased. This means that even though DME has been known to be a clean fuel for soot formation, the mixing of DME in diffusion flame of ethylene, where acetylene maintains high concentration in soot formation regions, could produce enhanced production of soot.

• Journal of IKEEE
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• v.21 no.2
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• pp.123-129
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• 2017

Proton Exchange Membrane Fuel Cell (FEMFC) is a strong candidate for future automobile and power generation because of its high power density, low emission and low operation temperature. The major concerns of the gas diffusion layer (GDL) inside a FEMFC is water management. The GDL is typically comprised of carbon for electrical conductivity and PTFE for Hydrophobicity. In this simulation, GDL flooding was investigated using a simplified approach method of an established equation models(Fick' Law, Darcy, Law, Stefan-Maxwell diffusion). The performance of GDL was shown using result of the inner heat, water density and oxygen density of the cell using model equations. The catalyst layer mode in FEMFC showed results of effectiveness factor, Butler-volmer and hydrogen flux density. These results are interesting because the influence of several factors has been shown and the information will be helpful for fuel cell design.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.123-131
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• 2012

As the price of traditional fuels soar, the alternatives are becoming more viable. And manufacturers are promoting the growing viability of electric and biofuel-powered vehicles through longer warranties. Now, these longer green environment (emission)warranties, sometimes called extended warranties or "super warranties," have been adapted. The main result of this paper is to present a new method to approximate a bivariate warranty function by using Radial Basis Function Network with application of Radon Transform and its inverse which is used to reduce the dimension of the warranty space. This method consist of the following stages: First, by using the Radon Transform, the bivariate warranty function can be reduced to one dimensional function. Second, each of the one dimensional functions is approximated by using neural network technique into neural sub-networks. Third, these neural sub-networks are combined together to form the final approximation neural network. Four, by using the inverse of radon transform to this final approximation neural network we get the approximation to the given function. Also, we apply the above method to some green warranty data of automotive vehicle company.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.1
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• pp.38-44
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• 2009

Recently, the research focused on fuel cell hybrid vehicles (FCHVs) is becoming an attractive solution due to environmental pollution generated by fossil fuel vehicles. The proper energy control strategy will result in extending the fuel cell lifetime, increasing of energy efficiency and an improvement of vehicle performance. Battery state of charge (SoC) is an important quantity and the estimation of the SoC is also the basis of the energy control strategy for hybrid electric vehicles. Estimating the battery's SoC is complicated by the fact that the SoC depends on many factors such as temperature, battery capacitance and internal resistance. In this paper, battery charging time estimated by SoC is studied by using the speed response and current response. Hybrid system is consist of a fuel cell unit and a battery in series connection. For experiment, speed response of vehicle and current response of battery were determined under different state of charge. As the results, the optimal battery charging time can be estimated. Current response time was faster than RPM response time at low speed and vice versa at high speed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.6
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• pp.465-473
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• 2008

Type II compressed natural gas(CNG) storage vessels for automobiles have been acknowledged for their excellence and have recently become established in local regions. Their supply is not only to automakers in Korea such as Hyundai Motors but they are being increasingly exported. Although the available products have undergone safety evaluations and are certified by an authorized institution they are still short of the optimal design that is possible for such storage vessels. This research investigates the shape and thickness of the dome with the aim of optimizing the type II CNG storage vessels by using a finite element analysis technique. CNG storage vessels can be largely divided into 3 parts namely, the hear part, the cylinder part and the dome part. The head part is designed by means of a hot spinning process and this method is safer than that used in the design of the dome part even though its shape is similar. The thickness of the liners and reinforcing materials was optimized based on the requirements of the cylinder and dome parts. In addition, the shape of the dome, which is most suitable for Type II CNG storage vessels, is proposed by a process of review and analysis of various existing shape, and then conducting a structural stability evaluation to ensure the optimal design plan.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.1
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• pp.73-80
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• 1991

인류가 산업발전 등으로 인해 석유등 화석연료를 사용함에 따라 대기오염은 날로 악화되어 1952년 런던스모그 같은 참사를 맞이하였고 이에 각국은 이러한 대기 오염물질을 저감하기 위하여 노력한 결과 대기 오염물질은 낮아지고 있으나 이에 반해 이산화탄소 배출량 증가에 따른 지구 온난화 현상과 오존층 파괴는 지역적인 환경문제에서 번세계적인 환경문제로 확산 전개되고 있다. 특히 산업혁명후 화석연료의 급격한 사용증가로 인한 이산화탄소 배출량 증가는 지구를 온나화시키고 수십년 후에는 환경에 심각한 영향을 주게 되는 것은 의심할 여지가 없는 것으로 이는 지구환경문제 중에서 금회 최대의 과제로 대두되게 되었다. 이에 따라 1985년 UNEP 관리 이사회를 필두로 "지구환경보전에 관한 동경회의", "대기오염 및 기후변동에 관한 노드윅 회의", "백악관회의", "휴스톤 Summit" 등에서 이 문제가 거론되기 시작하여 '90. 8월에는 스웨덴에서 온난화에 대한 과학적 인식과 대책의 메카니즘을 정하기 위한 IPCC 4차 회의가 각국 대표들이 참석한 가운데 정치, 경제, 과학의 문제로 등장하여 우리생활의 근본을 좌우할 다각적인 논의가 진행된 바 있다. 또한 미국, 영국, 일본 등 선진국들의 정상이 모이는 G7 회담 등에서 논의되고 있는 것들 중 정치적인 문제를 제외하고는 환경문제를 가장 많이 다룬다는 외신보도를 우리는 여러번 접한바 있다. 현재 국제적 환경문제로 가장 관심이 집중되고 있는 문제 중 몇가지를 소개하면 우선 <몬트리올의 정서에 의한 오존층 보호>를 들 수 있겠고, 최근 국제 협약 제정을 추진하고 있는 "지구온난화 방지에 관한 기후협약" 그리고 유해폐기물의 국제교역에 관한 "바젤협약"과 함께 새로이 제기된 "생물학적 다양성 협약"등이 거론되고 있으며, 이에 덧붙여 미국의 "자동차배출가스 규제"도 우리나라 산업에 큰 영향을 미칠 것으로 판단된다. 본 논문은 이중 대기와 관련된 오존층 보호와 지구온난화 대책에 대한 국제회의 등에서 현재까지 논의되었거나 토의될 내용에 대하여 기술하고 특히 금년부터 집중적으로 국제협상이 진행될 지구온난화 문제에 대한 최근의 국제동향 우리나라의 입장을 기술하고자 한다.

• Journal of the Korean Electrochemical Society
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• v.6 no.1
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• pp.23-27
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• 2003

In this study investigations have been carried out for the evaluation of small DMFCS under passive operation conditions for use in portable powers. Under passive conditions, a maximum performance was obtained at a methanol concentration of 4 M and at a catalyst loading of $8mg/cm^2$ on both electrodes. By optimizing various parameters, we could achieve the highest performance of $55mW/cm^2$ at 1 attn and at R.T.A monopolar stack consisting of 6 unit cells with active area of $4.5cm^2/cell$ was prepared and it showed a uniform voltage distribution all over the cells and it had a power output of 1 watt and a power density of $37mW/cm^2$ A monopolar stack which consisted of 16 cells and produced a 2.4W power was also fabricated and was tested for operation of a miniature car.