マリンエンジニアリング
Online ISSN : 1884-3778
Print ISSN : 1346-1427
ISSN-L : 1346-1427
48 巻 , 5 号
選択された号の論文の26件中1~26を表示しています
特集 舶用電気設備の技術動向
随想
技術資料
解説
特集 CFDの活用
随想
解説
技術資料
論文
  • 西村 真佐人, 清水 悦郎, 大出 剛
    2013 年 48 巻 5 号 p. 670-675
    発行日: 2013/09/01
    公開日: 2014/09/02
    ジャーナル フリー
     The possible cruising distance of the electric boats is still short compared with that of similar-sized internal combustion engine boats. Currently, electric boat operators have to estimate the possible cruising distance from weather (wind direction or power), wave (height and tide), and battery (voltage, current, state of charge) conditions. Battery failure has to be avoided from the viewpoint of operational safety. In order to solve this problem, a Navigation Support System (NSS) that provides the possible cruising distance and the recommended speed, and restricts the output power to achieve the desired operation, was developed. In this paper, in order to realize this system, an estimation algorithm and an output power restriction algorithm based on the analysis of characteristics of the boat, the motor and the battery discharge is derived. Verification tests in actual seas confirm the system’s usability.
  • 段 智久, 大上 雅貴, 西村 裕大, 浅野 一朗
    2013 年 48 巻 5 号 p. 676-683
    発行日: 2013/09/01
    公開日: 2014/09/02
    ジャーナル フリー
     The authors have investigated the effects of liquefied Dimethyl Ether (DME) mixed with conventional fuels of diesel engines. From those studies, it was clarified that DME mixing can drastically reduce unburned exhaust emissions, such as CO, HC and Particulate Matter (PM). However, the effect of sulfur content in fuels was not clearly examined. In this study, combustion analysis was carried out by varying sulfur ratio in fuels using a small size direct injection four stroke diesel engine. The test fuels were low sulfur Marine Diesel Oil (MDO, JIS A heavy oil) and MDO/DME mixed fuel. Di-t-butyl Disulfide (DBDS) was added to change the sulfur component ratio of those fuels. Experimental results obtained show that the injection duration and the specific fuel consumption increase with increasing the sulfur ratio in fuels, while the ignition delay decreases with an increase in sulfur ratio. Results also show that even though the sulfur content was increased, NOx emission and PM emission were reduced with DME mixing. It is assumed that the transfer rate of sulfur in fuel to sulfate in PM is in the range of 1.0 to 2.4% for MDO base fuel, and 0.4 to 0.9% for DME mixed fuel.
  • Bondarenko Oleksiy, Tetsugo Fukuda, Dong-Hoon Yoo, Katsuji Tanizawa
    2013 年 48 巻 5 号 p. 684-691
    発行日: 2013/09/01
    公開日: 2014/09/02
    ジャーナル フリー
     Growing interest in the numerical simulation of total ship propulsion plant demands an easy to handle diesel engine simulation tool in a field which is as extensive as there are applications — every design process or research project has its own fit-for-purpose model. Moreover, engine simulation is a trade-off between model simplicity, execution time, and accuracy. In this paper attention is focused on the development of a diesel engine dynamics simulation model which combines fast-simulation time, sufficient accuracy, and limited engine data requirement. The cycle mean value modeling methodology is adopted in this paper and the derived results were validated against experimental data of prototype engine.
  • 柳 東勲, 林 美鶴, 新田 好古, 藤田 浩嗣
    2013 年 48 巻 5 号 p. 692-698
    発行日: 2013/09/01
    公開日: 2014/09/02
    ジャーナル フリー
     Diesel engines are used as the main power source of marine transport and the continuous improvement of their performance offers better specific fuel oil consumption (SFOC). From the standpoint of Carbon Dioxide (CO2) emission, marine engines are environment friendly compared to those used in land transportation and other industries. Attention should be focused only on CO2 emissions but also on other greenhouse gases (GHG), such as Nitrous Oxide (N2O), which is the result of a reaction between nitrogen and sulfur components of low-grade fuels.
     N2O is known as the third major GHG following CO2 and methane (CH4). The global warming potential (GWP) of N2O is 310 times as large as that of CO2 because N2O in the atmosphere is very stable, and it becomes a source of secondary contamination after photo-degradation in the stratosphere. N2O concentration 1800 years before was less than 280 ppb, but in the last 200 years it has increased rapidly. Since N2O emission from natural sources is very difficult to control, discussions on N2O emission reductions should be centered on artificial N2O which represents 35% of the total N2O emissions. To argue this point, it should be noted that there are some reports on the N2O exhaust characteristics from stationary power plants and land transportations, but those of marine transportations are very limited.
     In this experimental study, the authors investigated N2O emission characteristics of an actual ship at the sea, and examined relationships between N2O and other gaseous emissions. The experimental results showed that N2O emission exhibited different characteristics compared with NO which makes up over 80 percent in NOX, and had exhaust characteristic very similar to SO2 emission. But when based on the excess air ratio, the difference between these two species increased with decreasing excess air ratio.
報告
製品紹介
コラム
シニアサロン
feedback
Top