• Journal of Hydrogen and New Energy
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• v.27 no.6
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• pp.721-726
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• 2016

Alcohols are particularly attractive as alternative fuels because they are a renewable resource. This paper describes the performance and emission characteristics of ethanol and diesel blended fuels in a compression ignition engine. This experimental results showed that ethanol diesel blended fuels decreased the torque and brake mean effective pressure. And experimental results indicated that using ethanol-diesel blended fuel, smoke, CO and HC emissions decreased as a result of the ethanol addition.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.51-57
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• 2014

High pressure common rail injection technology has revolutionized the diesel industry. Over the last decade it has allowed engine builders to run higher injection pressures as much as above 1,300bar in order to increase engine efficiency, while reducing emissions. This common rail system has low pressure circuit which is consist of low pressure pump, cascade overflow valve and flow metering unit. The low pressure pump's purpose is to feed fuel oil to the high pressure pump. The cascade overflow valve keeps pressure in front of the metering unit constant and provides lubrication for the high pressure pump. The metering unit, known as the MPROP or fuel pressure regulator, regulates the maximum flow rate delivers to the rail. In this paper, we have investigated the performance characteristics of each components and total low pressure circuit of common rail system.

• Journal of Power System Engineering
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• v.18 no.4
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• pp.72-77
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• 2014

The aim of this study to investigate polarization characteristics of WC-based alloy coatings fabricated by high velocity oxygen fuel(HVOF) process. The coatings were fabricated by HVOF process with WC-CrC-Ni, WC-Co-Cr, WC-Co composite powders. Corrosion tests were carried out using potentiostat/galvanostat at solution with pH 2 and pH 6. Corrosion potential(Ecorr) and corrosion current density(Icorr) could be analyzed from polarization curve. WC-Co-Cr coating showed more incorrodible characteristics than other coatings at solution pH 2. WC-CrC-Ni coating was more favorable anti-corrosion characteristics than other coatings at solution with pH 6.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.311-315
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• 2008

Currently, in automobile industry. the efforts to reduce the manufacturing cost by changing the process of manufacturing are continually performed. In this paper, we proposed a new manufacturing process, the roll bending of a ring plate of automotive fuel tank instead of conventional press blanking process to reduce material loss and manufacturing cost. Finite element analysis was used to optimize the roll bending process to assure rectangular cross-section of the ring plate. Also, spring-back analysis after the roll bending was performed and dimension of the bending die considering spring-back was analyzed. Finally, we verified a possibility for realization of the proposed method shape with prototypes.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.107-109
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• 2006

This study focuses on a determination of amount of Pt in the Pt/C for catalysts of polymer electrolyte membrane fuel cells (PEMFC). PEMFC offer low weight and high power density and being considered for automotive and stationary power applications. The PEMFC performance is influenced by several factors, including catalysts and structure of electrode and membrane type. Catalyst of electrode is important factor for PEMFC. One of the obstacles prevent ing polymer electrolyte membrane fuel cells from commercialization is the high cost of noble metals to be used as catalyst, such as platinum To effectively use these metals, they have to be will dispersed to small particles on conductive carbon supports. The optimal amount of Pt in Pt/C for cathode catalyst was investigated by using polarization curves in single cell with $H_2/O_2$ operation.

• Transactions of Materials Processing
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• v.31 no.6
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• pp.394-403
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• 2022

In the automotive industry, cold-drawn austenitic stainless steel is commonly used to handle high fuel pressures in gasoline direct injection (GDI) engines. In this study, we analyzed the effects of main process variables such as cross-sectional shape, drawing speed and friction coefficient on the microstructure, hardness and residual stress of the drawn material in the two-step cold drawing process. By changing the cross-sectional shape in the first-step cold drawing, the possibility of improving the shape accuracy or physical properties of the finally cold-drawn fuel rail pressure sensor product was investigated.

• Prospectives of Industrial Chemistry
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• v.22 no.4
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• pp.1-12
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• 2019

최근 전 세계적으로 이상화탄소 배출규제에 대응하기 위해 신에너지를 동력원으로 하는 자동차에 관심이 증가하고 있다. 그중 이온 교환막 연료전지(PEMFC)는 내연기관을 대신에 자동차 동력원으로 많이 사용되어지고 있으며 양산화를 위한 노력을 전 세계적으로 하고 있다. 하지만 이러한 수소 자동차가 시장과 소비자의 요구 조건을 충족하기 위해서는 내구성을 개선하여야 한다. 현재 선진사들을 중심으로 수소 자동차의 내구성을 개선하기 위해 노력하지만, 대부분 실험적 방법으로 내구성의 분석 및 평가를 수행하고 있다. 하지만, 이러한 방법은 비용과 시간이 많이 들기 때문에 경제적이지 못하다. 본 기고문에서는 내구성에 영향을 받는 인자, 연료전지 시스템 내구성을 예측하고 평가할 수 있는 수소 자동차 내구성 모델 개발에 필요한 수식에 관한 연구, 그리고 내구성 개선을 위한 해석적 방법(simulation)에 관한 연구 동향을 소개하고자 한다.

• Journal of Hydrogen and New Energy
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• v.35 no.2
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• pp.230-239
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• 2024

Efforts are being made to replace ship diesel engines with electric propulsion motors in response to emission regulations. In particular, in the case of short-range small ships, research is being conducted to replace polymer electrolyte membrane fuel cells (PEMFC) with power sources. However, PEMFC has problems such as slow dynamic response characteristics and reduced durability at high temperatures. To solve this problem, a high-precision ship model was developed with power distribution and thermal management strategies applied, and through this, the required power, heat, and power characteristics of the propulsion system according to the ship's speed profile were analyzed.

• Journal of Hydrogen and New Energy
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• v.26 no.1
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• pp.1-7
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• 2015

In this study, characteristics of reforming process of automotive liquefied petroleum gas (LPG) fuel using plasma reactor are investigated. Because plasma reformer technology has advantages of a fast start-up and wide fuel/oxidizer ratio of operation, and reactor size is smaller and more simple compared to typical combustor and catalytic reactor, plasma reforming is suitable to the on-board vehicle reformer. To evaluate the characteristics of the reforming process, parametric effect of $O_2/C$ ratios, reactant flow rate and metal form on the process were investigated. In the test of varying $O_2/C$ ratio from partial oxidation to stoichiometry combustion, conversion of LPG was increased but selectivity of $H_2$ decreased. The optimum condition of $O_2/C$ ratio for the highest $H_2$ yield was determined to be around 1.0 for 20~50 lpm, and 1.35 for 100 lpm. Specific energy density (SED) was major factor in reforming process and higher SED leads to higher $H_2$ yield. And metal form in the reformer increased $H_2$ yield of about 34 % as compared to the case of no metal form. The result can be a guide to map optimal condition of reforming process.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.6
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• pp.662-670
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• 2005

With highly oxygenated fuels the smoke emissions decreased sharply and linearly with increases in the fuel oxygen content and entirely disappeared at an oxygen content of $38wt-\%$ even at stoichiometric mixture conditions The NOx also decreased monotonically with increases in oxygen content. and thermal efficiency slightly improved because of a reduction in cooling loss and improvement in the degree of constant volume combustion. The mechanisms of the significant reductions in emissions and improvement in engine performance were analyzed with a bottom view type DI diesel engine. Together with direct flame images, flame images were taken through an optical fetter passing only two wavelengths for use in 2-D two-color analysis. The results showed that luminous flame decreased significantly with increases in oxygen content and was not detected for neat dimethoxy methane(DMM). The decrease in flame luminosity with highly oxygenated fuels corresponds with decreases in soot and cooling losses, including those due to heat radiation. The 2-D two-color flame analysis indicated that the high temperature flame and high KL factor areas apparently decreased with increasing fuel oxygen content. These results correspond strongly with decreases in NOx. smoke. and cooling loss with increases in oxygen content.