• Title, Summary, Keyword: 디젤기관

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A Study on the Cycle Analyzing and Intake Valve Control by the Miller Method with a High Expansion into Low-Speed Diesel Engine (저속 디젤기관에서 고팽창의 밀러방식에 의한 사이클 해석 및 흡기밸브제어에 대한 연구)

  • Jag, Tae-Ik
    • Journal of the Korean Society of Marine Engineering
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    • v.33 no.8
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    • pp.1100-1106
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    • 2009
  • Recently, there are quite a lot of attention is drown on the researches related to of Miller method applied high expansion cycle. For this study, high expansion cycles are formed and analyzed with the base view point of thermodynamics, and the features of each factors are also investigated. As a result of analysis, the expansion-compression ratio is expected with a decrease of effective compression ratio as intake valve closing time retarded, however, the decrease of mean effective pressure and its output is accompanied with the counterflow of intake air. Accordingly, as the consequence of such failure, it is expected that an alternative is needed for the realization of high expansion cycles, and the improvement over thermal efficiency. To materialize such cycle, the control system to delay the closing time of intake valve was designed and VVT, the 3 S/B low speed diesel engine, is applied to evaluate the efficiency. The result of the trial shows that there was no significant errors.

An Experimental Study on Effects of EGR Rate upon Exhaust Emissions in Small High-Speed Diesel Engines (소형 고속 디젤기관의 배기 배출물에 미치는 배기 재순환율의 영향에 관한 실험적 연구)

  • 임재근;배명환;김종일
    • Journal of the Korean Society of Marine Engineering
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    • v.16 no.4
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    • pp.60-77
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    • 1992
  • The effects of exhaust gas recirculation(EGR) on the characteristics of exhaust emissions and specific fuel consumption have been investigated using an eight-cylinder, four cycle, direct injection diesel engine operating at several loads and speeds. The experiments in this study are conducted on the fixed fuel injection timing of $38^{\circ}$ BTDC regardless of experimental conditions. In conclusion, it is found that $NO_{x}$ emission is markedly reduced with the drop of burnt gas temperature at high speeds and loads especially as the EGR rate increases, while the soot particulate rises with EGR rate and load at a given engine speed, especially high loads. The reduction of exhaust emissions within the Korea heavy duty diesel engine emission standards can be roughly achieved by the optimal EGR rate without degarding the specific fuel consumption, based on the correlations between exhaust emissions.

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Study on Smoke Prediction in Heavy-duty Diesel Engine (대형 디젤기관에서 매연가스 예측에 관한 연구)

  • Baik, Doo-Sung;Lee, Jong-Sun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.4
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    • pp.865-870
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    • 2008
  • The effects of exhaust gas recirculation (ECR) on smoke emissions in heavy duty diesel engine are numerically studied by using KIVA-3V CFD code. For the analysis, RNG k-$\varepsilon$ turbulence model was given as a governing equation, and mathematical models of Tab, Wave, Watkins-Park, Nagle-Strikland were applied to describe physical process of droplet breakup, atomization, wall impingement and smoke respectively.

Vegetable oils for diesel fuel substitutes (디젤기관의 대체연료로서의 식물유)

  • 오영택
    • Journal of the korean Society of Automotive Engineers
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    • v.18 no.2
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    • pp.72-92
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    • 1996
  • 식물유, 어유 및 축산 폐기물을 포함한 동식물성 기름은 어느 연료든지 기관의 연료로서 사용 가능하지만, 이들 연료는 점도가 높고, 저휘발성이어서 착화지연기간동안에 가연성혼합기 생성이 어려워 저 NOx이며, 정숙한 운전이 사능할 뿐 아니라 경유정도의 열소비율 및 배기 매연농도로 디젤기관의 대체 연료로서의 충분한 가능성이 있는 연료임을 확인하였다. 그러나, 고점도에 의한 분무 특성의 악화에 기인한 분무입자의 증대로 미연소분에 의한 carbon deposit 및 piston ring stick 등이 문제점으로 지적되었다. 그러나, 이같은 문제점의 해결책으로 경질유와의 혼합, 에스테르 변환 및 연료의 가열등 여러 해결책을 제시하였고, 배기가스분석결과도 양호함을 확인하였다. 이같은 biomass 연료 일종인 식물유가 아무런 변화없이 이용되기 위해서는 고과급화, 단열 및 연소실의 적절한 설계가 필요할 것으로 생각된다. 따라서, 현재의 실황을 생각한다면 기존기관을 특별하게 개조함이 없이 사용을 전제로 할 때 식물유의 이용은 local 에너지로서, 생산, 전환 또는 이용기술의 개발과 동시에 화석에너지의 보충적인 에너지로 고려하는 것이 유효할 것으로 생각된다.

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Development of Simulation Program of Two-Stroke Marine Diesel Engines (선박용 2행정 디젤기관의 성능시뮬레이션 프로그램 개발)

  • Choi, Jae-Sung;Jeong, Chan-Ho;Cho, Kwon-Hae;Lee, Jin-Uk;Ha, Tae-Bum;Kim, Houng-Soo
    • Journal of the Korean Society of Marine Engineering
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    • v.34 no.1
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    • pp.62-68
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    • 2010
  • The requirement of high efficiency and low emission for marine diesel engines are being enforced because of air pollution and climate change on the earth. In connection with these, many new technologies are considered. But they are mainly for new building ship. It is necessary to be concerned about the improvement of engine performance for existing ship. In this paper, the simulation program for performance of marine two-stroke diesel engine was developed to predict the deteriorating performance according to elapsed time for existing ship. The result was compared with the result of the program named TOP-CODE which was used by engine maker and checked to be shown good agreement between them.

A Study on the Performance of Diesel Automobile Engine with Ultrasonic Fule Supply System(III) (On the case of Turbo-charging Diesel Engine) (초음파 연료공급장치용 디젤자동차의 성능 향상에 관한 연구(III) (과급 디젤기관에 대하여))

  • 최두석;이흥영;류정인
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.4
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    • pp.12-18
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    • 1995
  • To improve the performance of diesel automobile engine, we designed new fuel supply system named ultrasonic fuel supply system. The performance test of diesel automobile engine carried out to examine possibility of practical use of ultrasonic fuel supply system to test engine. This paper deals with the comparative results of performance test of diesel automobile engine in terms of smoke, HC, SFC, PS, thermal, efficiency, torque. Following are obtained result. 1) In naturally aspirated diesel engine, when we use ultrasonic fuel supply system output, fuel consumptions are improved and exhaust gas reduced significantly. 2) In turbo-charging diesel engine both using of ultrasonic fuel supply system and using of conventional injector, engine performance and exhaust gas temperature are almost constant. 3) In turbo-charging diesel engine, when we use ultrasonic fuel supply system, NOx are emitted approximately 3.5% higher than total average. 4) In turbo-charging diesel engine, when we use ultrasonic fuel supply system, smoke and CO are 17% and 11.8% improved respectively.

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A Basic study on the Evaporative Diesel Spray with Visible Measurement (가시화 측정을 이용한 증발디젤분무의 기초 연구)

  • Yeom, J.K.
    • Journal of the Korea Society For Power System Engineering
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    • v.13 no.3
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    • pp.20-26
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    • 2009
  • 디젤기관에서 배출되는 유해배출성분인 NOx(Nitrogen oxides)와 PM(Particulate matter)은 기관 실린더내의 혼합기 분포에 의해 그 생성이 지배된다. 이 때문에 그 유해배출물들을 저감하기 위해서는 연소의 전단계인 혼합기 분포 및 그 생성과정의 해석은 매우 중요하다. 디젤기관에서 노즐로부터 분사된 연료는 주위기체와 혼합기를 형성하는 과정에서 액체에서 기체로 상변화를 동반한다. 따라서 분무의 혼합기형성과정을 해석하기 위해서는 액상과 기상을 동시에 분리하여 계측하는 것이 필요하다. 그러므로 본 연구에서는 디젤분무를 대상으로 Melton 등이 제안한 엑시플렉스(Exciplex) 형광법을 이용하여, 분무의 액상과 기상을 동시에 2차원분리해서 가시화촬영을 행하였다. 그 엑시플렉스 형광법을 이용하여 획득한 이미지에 화상 응용해석을 실시하여 비정상증발디젤분무의 혼합기형성과정에 대한 정보를 얻고자 하였다. 엑시플렉스 형광법을 이용해서 증발분무의 거동측성을 해석한 결과 프랙틸해석을 이용한 분무 흐트러짐(Disturbance)의 평가에서 플랙틸차원은 분사압력의 변화에 관계없이 하나의 값, 약 1.1로 정리 할 수 있고, 그 결과 각 분사압력에 대한 분무 기상외곽곡선(외주)은 거의 동일한 정도의 요철형상을 갖는다.

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Diesel Engine Combustion Characteristics on the Natural Gas Mixing (천연가스 혼합에 의한 디젤기관의 연소특성)

  • Park, Myung-Ho
    • Journal of the Korean Institute of Gas
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    • v.11 no.1
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    • pp.9-12
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    • 2007
  • In this study, a new method of combustion characteristics have been proposed to reduce exhaust emissions in a diesel engine using four kinds of mixed fuel. Mixed fuels show four different torque ratios between diesel oil md natural gas, which are 4:0, 3:1, 2:2 and 1:3. In order to investigate the exhaust gas during combustion, exhaust gases are sampled by gas analyzer, for example NOx, Soot, CO, and HC, as the RPM changed. As a result, the NOx, CO, and HC concentrations of mixed fuel are higher than those of diesel oil only. However, the Soot concentration of mixed fuel is lower when diesel oil is burned.

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Emission factors based estimation of exhaust emissions with biodiesel blended fuel from naval vessel propulsive diesel engine (바이오디젤 혼합연료를 사용하는 함정추진디젤기관의 배출계수를 이용한 배기가스 배출량 예측)

  • Lee, Hyungmin
    • Journal of the Korean Society of Marine Engineering
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    • v.37 no.4
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    • pp.332-337
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    • 2013
  • National investment was performed in the research and development of renewable energy because of climate change by air pollution, exhaustion of energy sources, energy security, and so on. Biodiesel fuel of the renewable energy is highlighted as friendly environment energy, it is possible to operate in regular diesel engines when it is blended with invariable ratios without making any changes. Emission factors have been estimated for commercial ship from various research institutes; however, it is difficult to develop emission factors for military vessels. In this work, biodiesel blended fuel emission factors for sulfur dioxide and carbon dioxide were quantitatively estimated from propulsive diesel engine installed on naval vessel using fuel property analysis. In addition, exhaust emissions were quantitatively calculated on the basis of fuel consumption rate with biodiesel content by percentage.