• 제목/요약/키워드: Egr1

검색결과 154건 처리시간 0.026초

ABS LNG Ready - S Notation 적용에 따른 기본설계 변경사항 검토 (A Study on the Basic design changes according to the application of LNG Ready - S Notation)

  • 송다혜
    • 대한조선학회 특별논문집
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    • 대한조선학회 2017년도 특별논문집
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    • pp.54-58
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    • 2017
  • The vessels which are operated in ECA (Emission Control Area) after $1^{st}$ January 2016 shall be complied with revised NOx emission requirement (Tier III). Effective solutions for NOx emission requirement are SCR (Selective Catalytic Reduction), EGR (Exhaust Gas Recirculation) and Installation of LNG Dual Fuel Engine. This study is considered the design modification as per application of LNG Ready notation. In case of LNG Ready - S notation, the vessel shall be retrofitted the Main engine with Dual fuel engine and LNG Fuel system after delivery. On this paper, the entire process for design modification was explained to meet the requirement for LNG Ready notation.

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소득분포 극화의 추정과 검증 (Estimation and Verification for Polarization of Income Distribution in Korea)

  • 유경준
    • KDI Journal of Economic Policy
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    • 제29권3호
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    • pp.1-28
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    • 2007
  • 본고의 분석 결과 지니계수와 양극화지수가 이론적으로는 상이하나, 실증적으로는, 상관관계를 통해서 볼 때, 다른 지수라 보기 어렵다는 점이 확인되었다. 또한 DER지수의 추정을 통해 한국소득분포의 극화를 추정한 결과도 외환위기 전후로 소득분포의 극화가 지니계수로 측정되는 소득불평등도보다 심화되었다고 여길 수 없음이 확인되었다.

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배기가스 재순환장치 효율 증대 방안 (The Plan to Increase Efficiency of Exhaust Gas Recirculation System)

  • 김광수;정순석;허윤복
    • 대한안전경영과학회지
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    • 제16권3호
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    • pp.185-194
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    • 2014
  • Internal engine is the main power source of vehicle and is the main source of air pollution. To satisfy this getting rigorous emission regulation, it must be solved simultaneously the dilemma of reducing emission gas and increasing heat efficiency. Diesel engine is preferred compare with gasoline engine in aspect of energy consumption but it must be solved reducing the containing of NOx, CO and HC. In this study: 1. Looking for alternative of performance improvement of Exhaust Gas Recirculation(EGR) which is emission gas reduction system. 2. Reducing malfunction of controlling emission gas. 3. Made possible precision control.

분위기 가스 변화에 의한 폴리스틸렌 구의 미소중력 연소특성 (Microgravity Combustion Characteristics of Polystyrene Spheres with Various Ambient Gases)

  • 최병철;이토켄이치;후지타오사무
    • 대한기계학회논문집B
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    • 제25권11호
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    • pp.1509-1517
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    • 2001
  • An experimental and numerical analysis were conducted to investigate the transient temperature distribution and flame propagation characteristics over an inline polystyrene spheres under microgravity. From the experimental, a self-ignition temperature of polystyrene bead was 872 K under gravity. Flame spread rates were 4.7-5.1 mm/s with ambient gas N$_2$and 2.3-2.5 mm/s with ambient gas CO$_2$, respectively. Flame radius diameters were 17 mm with ambient gas N$_2$and 9.6 mm with ambient gas CO$_2$, respectively. These results suggest that the flame propagation speed could be affected in the Diesel engine and the boiler combustor by EGR. In terms of the flame spread rate and the transient temperature profile, numerical results have the qualitative agreement with the experiment.

흡기 포트 내 물 분사에 의한 디젤 기관의 배기 유해물 배출 및 기관 성능 변화에 관한 실험적연구 (An Experimental Study on the characteristic of Exhaust Emissions and the Engine Performacne with Intake Port Water Injection in Diesel Engine)

  • 김기형
    • Journal of Advanced Marine Engineering and Technology
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    • 제23권1호
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    • pp.25-32
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    • 1999
  • This study was carried out to reduce NOx emissions from diesel engine and to investigate the variation of engine performance using the water injection. In this study the water was extracted from the exhaust gas and injected directly into the intake port with the inlet charge. The water condensing system operated as a closed system without any supplementary water supply. The experimental parameters such as the revolution the torque and the water injection rate are varied and the result from this experiment found the significant NOx reduction whereas the smoke emission increases as water/air ratio increases as the cases like the EGR. In spite of increasing the quantity of the water injection the engine output was slightly decreased and the specific fuel consumption was increased as was anticipated. Especially the system was founded to be effective on the reduction of the NOx emissions at the high load region relatively.

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저온연소조건에서 급속압축기를 이용한 n-heptane/n-butanol 혼합연료의 착화지연에 관한 연구 (The investigation on the Ignition Delay of n-heptane/n-butanol Blend Fuel Using a Rapid Compression Machine at Low Temperature Combustion Regime)

  • 송재혁;강기중;;;최경민;김덕줄
    • 한국연소학회지
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    • 제18권2호
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    • pp.32-41
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    • 2013
  • This study presents both experimental and numerical investigation of ignition delay time of n-heptane and n-butanol binary fuel. The $O_2$ concentration in the mixture was set to 9-10% to make high exhaust gas recirculation( EGR) rate condition which leads low NOx and soot emission. Experiments were performed using a rapid compression machine(RCM) at compressed pressure 20bar, several compressed temperature and three equivalence ratios(0.4, 1.0, 1.5). In addition, a numerical study on the ignition delay time was performed using CHEMKIN codes to validate experimental results and predict chemical species in the combustion process. The results showed that the ignition delay time increased with increasing the n-butanol fraction due to a decrease of oxidation of n-heptane at the low temperature. Moreover, all of the binary fuel mixtures showed the combustion characteristics of n-heptane such as cool flame mode at low temperature and negative-temperature-coefficient(NTC) behavior. Due to the effect of high EGR rate condition, the operating region is reduced at lean condition and the ignition delay time sharply increased compared with no EGR condition.

디젤 저온연소 운전 영역에서 흡기압이 엔진 성능에 주는 영향 (Effect of Intake Pressure on Emissions and Performance in Low Temperature Combustion Operation of a Diesel Engine)

  • 이선엽;장재훈;이용규;오승묵;김용래;김득상
    • 한국자동차공학회논문집
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    • 제20권1호
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    • pp.88-94
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    • 2012
  • One of the effective ways to reduce both $NO_x$ and PM at the same time in a diesel CI engine is to operate the engine in low temperature combustion (LTC) regimes. In general, two strategies are used to realize the LTC operation-dilution controlled LTC and late injection LTC - and in this study, the former approach was used. In the dilution controlled regime, LTC is achieved by supplying a large amount of EGR to the cylinder. The significant EGR gas increases the heat capacity of in-cylinder charge mixture while decreasing oxygen concentration of the charge, activating low temperature oxidation reaction and lowering PM and $NO_x$ emissions. However, use of high EGR levels also deteriorates combustion efficiency and engine power output. Therefore, it is widely considered to use increased intake pressure as a way to resolve this issue. In this study, the effects of intake pressure variations on performance and emission characteristics of a single cylinder diesel engine operated in LTC regimes were examined. LTC operation was achieved in less than 8% $O_2$ concentration and thus a simultaneous reduction of both PM and $NO_x$ emission was confirmed. As intake pressure increased, combustion efficiency was improved so that THC and CO emissions were decreased. A shift of the peak Soot location was also observed to lower $O_2$ concentration while $NO_x$ levels were kept nearly zero. In addition, an elevation of intake pressure enhanced engine power output as well as indicated thermal efficiency in LTC regimes. All these results suggested that LTC operation range can be extended and emissions can be further reduced by adjusting intake pressure.

농용 디젤기관에서 매연과 NOx의 동시저감에 관한 실험적 연구 (An Experimental Study on Simultaneous Reduction of Smoke and NOx in a Agricultural Diesel Engine)

  • 최승훈;오영택
    • 한국자동차공학회논문집
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    • 제11권3호
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    • pp.85-91
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    • 2003
  • In this study, the potential possibility of oxygenated fuel such as Methyl tertiary butyl ether (MTBE) was investigated for the sake of exhausted smoke reduction from diesel engine. MTBE has been used as a fuel additive blended into unleaded gasoline to improve octane number, but the study of application for diesel engine was incomplete. Because MTBE includes oxygen content approximately 18%, it is a kind of oxygenated fuel that the smoke emission of MTBE is reduced remarkably compared with commercial diesel fuel. But, the NOx emission of MTBE blended fuel is increased compared with commercial diesel fuel. And, it was tried to analyze not only total hydrocarbon but individual hydrocarbon components from $C_1$ to $C_6$ in exhaust gas using gas chromatography to seek the reason for remarkable reduction of smoke emission. Individual hydrocarbons($C_1$~$C_6$) as well as total hydrocarbon of oxygenated fuel are reduced remarkably compared with diesel fuel. And, the effects of exhaust gas recirculation(EGR) on the characteristics of NOx emission has been investigated, too. It was found that simultaneous reduction of smoke and NOx was achieved with oxygenated fuel and cooled EGR method.

흡기밸브 닫힘 시기와 분사조건이 PCCI 엔진의 성능에 미치는 영향에 관한 연구 (A Study on Effect of the Intake Valve Timing and Injection Conditions on the PCCI Engine Performance)

  • 이재현;김형민;김영진;이기형
    • 한국분무공학회지
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    • 제15권1호
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    • pp.1-7
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    • 2010
  • As world attention has focused on global warming and air pollution, high efficiency diesel engines with low $CO_2$ emissions have become more attractive. Premixed diesel engines in particular have the potential to achieve the more homogeneous mixture in the cylinder which results in lower NOx and soot emission. Early studies have shown that the operation conditions such as the EGR, intake conditions, injection conditions and compression ratio are important to reduce emissions in a PCCI (Premixed Charge Compression Ignition) engine. In this study a modified cam was employed to reduce the effective compression ratio. While opening timing of the intake valve was fixed, closing timing of the intake valve was retarded $30^{\circ}$. Although Atkinson cycle with the retarded cam leads to a low in-cylinder pressure in the compression stroke, the engine work can still be increased by advanced injection timing. On that account, we investigated the effects of various injection parameters to reduce emission and fuel consumption; as a result, lower NOx emission levels and almost same levels of fuel consumption and PM compared with those of conventional diesel engine cam timing could be achieved with the LIVC system.

바이오 디젤 적용에 따른 대형엔진의 배출가스 특성 (The Emission Characteristics of Bio-Diesel Fuel in Heavy-Duty Engine)

  • 김선문;엄명도;홍지형
    • 한국대기환경학회지
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    • 제26권5호
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    • pp.499-506
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    • 2010
  • Recently, a great deal of attention have been directed to the use of alternative fuels as a means to reduce vehicular emissions. As one of the promising alternative fuels, bio-diesel has advantages of a wide adaptability without retrofit of diesel engine. It is also effective enough to reduce CO, THC, $SO_x$, polycyclic aromatic hydrocarbons (PAHs) and PM. In this study, we investigated the emission characteristics of biofuels between different operating conditions, i.e., engine speed (1,400 rpm and 2,300 rpm), engine load (10% and 100%), bio-diesel blending (BD0, BD5 and BD20), and recirculation (EGR) rate of exhaust gas (0% and 20%). Relative performance of the system was evaluated mainly for the greenhouse gases ($CH_4$, $N_2O$ and $CO_2$). In addition, emission characteristics of ND-13 mode were also tested against both greenhouse gases and other airborne pollutants under emission regulation. The relative composition of bio-diesel has shown fairly clear effects on the emission quantities of CO, THC, and PM emission, although it was not on $NO_x$ and greenhouse gases. EGR rate has shown trade-off characteristics between $NO_x$ and PM.