• 한국대기환경학회지
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• 제16권3호
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• pp.285-291
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• 2000

EGR(Exhaust Gas Recirculation) is known as the technique reducing the NOx emissions from diesel engine. Low pressure roote and high pressure roote are applied for heavy-duty diesel engine are. In this study, as research for the heavy duty diesel engine equipped with EGR, reduction characteristic of CO, THC, NOx, and PM in HD diesel engines are investigated by applying EGR device. Also, through the experiments using 11 liters, turbocharged diesel engine with EGR valve and intercooler, exhaust gas reduction characteristics were measured as changing in EGR rate according to D-13 mode.

• Journal of Advanced Marine Engineering and Technology
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• 제16권4호
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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.

• 한국자동차공학회논문집
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• 제10권6호
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• pp.59-64
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• 2002

The effects of EGR on emissions were investigated by using a six-cylinder, 8 litre, turbo-charged, heavy-duty diesel engine with a low pressure route EGR system. The experiments were performed at various engine loads while the EGR rates were set from 0% to 30%. Hot and cooled EGR are achieved without cooling and with cooling respectively. To verify the possibility of EGR technology for the applications, test were performed with steady state test cycle. It was found that the exhaust emissions with the EGR system resulted in a very large reduction in oxides of nitrogen at the expense of higher smoke and PM emissions. Increasing the EGR rate leads to deteriorating specific fuel consumption and power at lower speed and higher load. Also, the reduction rates of NOx emissions for hot and cooled EGR are similar.

• 한국자동차공학회논문집
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• 제13권5호
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• pp.188-194
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• 2005

The direct injection diesel engine is one of the most efficient thermal engines. For this reason DI diesel engines are widely used for heavy-duty applications. But the world is faced with very serious problems related to the air pollution due to the exhaust emissions of diesel engine. So, that is air pollution related to exhaust gas resulted from explosive combustion should be improved. Exhaust Gas Recirculation(EGR) is a proven method to reduce NOx emissions. In this study, the experiments were performed at various engine loads while the EGR rates were set from $0\%$ to $30\%.$ The emissions trade-off and combustion of diesel engine are investigated. The brake specific fuel consumption rate is very slightly fluctuated with EGR in the range of experimental conditions. The ignition delay increased with increasing EGR rate. The maximum value of premixed combustion for the rate of heat release is increased with increasing EGR rate. NOx emissions are decreased with increasing EGR rate at high load and high speed. It was found that the exhaust emissions with the EGR system resulted in a very large reduction in oxides of nitrogen at the expense of higher smoke emissions.

• 한국산학기술학회논문지
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• 제3권1호
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• pp.58-62
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• 2002

본 연구는 기관의 성능과 배출가스의 ECR 효과을 대한 것으로 기관은 6실린더 11리터의 대형터보디젤기관이며 ECR 방식은 저압루트시스템을 적용하였다. EGR 작동방식은 기계시이며 터빈 출구로부터 압축기 입구로 재순환시키는 방식이다. 또한 실험은 기관회전수와 부하별로 변경시켰으며 ECR율은 4%와 8%로 고정하여 실험하였고 그 결과를 기존 기관의 성능 및 배출가스결과와 비교 분석하였다. 따라서 본 연구의 목적은 대형터보디젤기관에 폭넓은 작동범위에서 ECR에 의한 기관 및 배출가스 성능에 미치는 영향을 고찰하고자 한다.

• 한국자동차공학회논문집
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• 제18권5호
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• pp.136-144
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• 2010

Exhaust gas recirculation (EGR) is an emission control technology allowing significant NOx emission reduction from light-and heavy duty diesel engines. The future EGR type, dual loop EGR, combining features of high pressure loop EGR and low pressure loop EGR, was developed and optimized by using a commercial engine simulation program, GT-POWER. Some variables were selected to control dual loop EGR system such as VGT (Variable Geometry Turbocharger)performance, especially turbo speed, flap valve opening diameter at the exhaust tail pipe, and EGR valve opening diameter. Applying the dual loop EGR system in the light-duty diesel engine might cause some problems, such as decrease of engine performance and increase of brake specific fuel consumption (BSFC). So proper EGR rate (or mass flow) control would be needed because there are trade-offs of two types of the EGR (HPL and LPL) features. In this study, a diesel engine under dual loop EGR system was optimized by using design of experiment (DoE). Some dominant variables were determined which had effects on torque, BSFC, NOx, and EGR rate. As a result, optimization was performed to compensate the torque and BSFC by controlling start of injection (SOI), injection mass and EGR valves, etc.

• 동력기계공학회지
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• 제17권6호
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• pp.130-135
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• 2013

It is a research about the change in reduction efficiency and performance resulting from installation of the EGR cooler, which is the core technology reducing NOx in response to standards been tightened of exhaust controls for off-road vehicle. It can reduce NOx by altering combustion temperature and oxygen concentration by recycling high-temperature exhaust gas. The target engine was large diesel engine for construction machine through by which we were able to verify a rate of change in output and capabilities for a heat-exchange within cooler itself depending on the existence of EGR cooler system. We have acquired a emission reduction technology for a construction machine by testing the reduction performance and rate of change in output.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.101-107
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• 2005

In this paper, optimized operating parameters were found using multi-dimensional engine simulation software (KIVA-3V) and micro-genetic algorithm for heavy duty diesel engine. The engine operating condition considered was at 1,737 rev/min and 57 % load. Engine simulation model was validated using an engine equipped with a high pressure electronic unit injector (HEUI) system. Three important parameters were used for the optimization - boost pressure, EGR rate and start of injection timing. Numerical optimization identified HCCI-like combustion characteristics showing significant improvements for the soot and $NO_X$ emissions. The optimized soot and $NO_X$ emissions were reduced to 0.005 g/kW-hr and 1.33 g/kW-hr, respectively. Moreover, the optimum results met EPA 2007 mandates at the operating point considered.

• 한국자동차공학회논문집
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• 제10권1호
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• pp.93-98
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• 2002

It is a present situation that the control on automobile emission is getting more restrictive and also the regulations for emission are changing greatly up to level of those advanced foreign countries. Specially, it has been many years that exhaust gases from gasoline automobile rather than from diesel is the major object concerned by Korea and other countries, and it is strongly required on the reduction techniques on harmful NOx and PM among those compositions. Thus, this research focused on the Exhaust Gas Recirculation (EGR) and the target fur this research is heavy-duty turbo-diesel engine with EGR, and conducted with numerical simulation to get engine performance and the characteristics of emission. Furthermore. the results obtained under different conditions such as rpm, power, EGR rate are compared and investigated with the numerical simulation using KIVA-3.

• 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.