著者

吉川 大雄 菱沼 孝夫 近久 武美 早坂 厚

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. B編 = Transactions of the Japan Society of Mechanical Engineers. B (ISSN:03875016)

巻号頁・発行日

vol.68, no.665, pp.218-223, 2002-01-25

参考文献数

12

被引用文献数

2

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The objective of this study was to estimate the optimization of fuel cell electric vehicle systems by the driving simulation that we developed. The results of the driving simulation showed the power of fuel cell, battery and motor for a 1 500 cc class sedan is 12, 18 and 15 kW at the condition of 10-15 mode of the minimum fuel consumption. The fuel consumption of the series driving system of FCEV was more than the parallel because of the heavier vehicle weight of the series compared to the parallel. The numerical analysis showed that the FCEV performance is affected by the regenerative brake and the fuel consumption of the FCEV with the regenerative brake systems is 23% less than without them.

著者

近久 武美 湯山 亮 菱沼 孝夫

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 B編 (ISSN:03875016)

巻号頁・発行日

vol.67, no.658, pp.1563-1570, 2001-06-25 (Released:2008-03-28)

参考文献数

11

被引用文献数

5 7

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Investigation on diffusion process is required in variety of field such as chemical reaction, combustion, and environmental studies. However, there is no appropriate index for analyzing degree of homogeneity and scales of the clouds in diffusion field. This paper pressents Entropic Method for determining the homogeneity degree and the scale of the heterogeneous clouds based on the statistic-entropy concept. The results of the investigation on the performance and characteristics of the method showed good correspondence between the analyzed results and the states of the tested pictures. A method for determining a mean effective diffusion-coefficient from the pictures is also discussed. The paper proposes an analitical method available for the study on diffusion phenomena.

著者

田部 豊 内山 真理 嶋田 遼 鈴木 研悟 近久 武美

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.849, pp.16-00458-16-00458, 2017 (Released:2017-05-25)

参考文献数

10

被引用文献数

1

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The vanadium redox flow battery (VRFB) is expected as a potential candidate for the next generation secondary batteries with large capacity because of its characteristics: flexible design of charging and discharging capacities, superior responsiveness and safety, and other advantageous characteristics. This study investigated the effects of active species transport in the electrolyte on the current density distribution and the cell performance of a VRFB experimentally and analytically. A method for measurements of the current density distributions along the electrolyte flow direction was developed using five segmented current collectors in flow through type electrodes. In this method, the segmented current collectors were kept equipotential by adjustable resistances. The experimental results showed that the current density during discharging decreases along the flow, and the difference between at the up and down streams becomes larger with higher current density, lower flow rate, and lower state of charge. The effects of electrolyte flow conditions at the negative electrode are larger than those at the positive electrode. An analytical model for evaluations of the active species transport and its contribution to the various types of overpotentials was also developed based on the experimental results. It was shown that the model can simulate the measured cell overpotentials and current density distributions quantitatively. In the model results, under the low current density conditions in this study, the current density distribution is caused mainly by the concentration overpotential due to decrease in active species concentration in the electrolyte flow, while the concentration overpotential at the electrode surface is kept relatively uniform and has a larger effect on an increase in total cell overpotential. As the current density increases, the distribution of the concentration overpotential at the electrode surface also becomes more uneven, and the largest overpotential at the downstream induces further deterioration of the cell performance.

著者

近久 武美 南里 尚宏 沢田 信之 本間 工士

出版者

北海道大学 = Hokkaido University

雑誌

北海道大学工学部研究報告 (ISSN:0385602X)

巻号頁・発行日

no.175, pp.p21-35, 1995-10

著者

吉川 大雄 菱沼 孝夫 近久 武美

出版者

一般社団法人日本機械学会

雑誌

日本機械学會論文集. B編 (ISSN:03875016)

巻号頁・発行日

vol.66, no.652, pp.3218-3225, 2000-12-25

被引用文献数

17

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The humidification system in a PEFC is handicapped by the water management under a range of temperatures including low temperatures in winter, so the performance with and without humidification was considered and simulated for a variety of fuel cell temperatures. The characteristice of a single cell with a cell area of 104 cm^2 was identified by experiments and a one dimensional model was developed to evaluate cell performance. The experiments found that water managements are important because the ionic conductivity of the membrane and catalyst layers decreases when there is little humidity. Results of start-up tests with the cell showed that the fuel cell recover the performance quickly in temperature as low as 10℃. The one dimensional simulation model showed that the measured cell performance agrees with the modeling results for various humidity conditions of the cell. If low reaction temperatures and low current densities are selected as operating conditions, it would be possible to apply the dry system at the start-up.