• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.35-42
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• 2001

The diesel engine exhaust gas is know as one of the causes to produce photochemical smog, which causes damage on environmental. However, due to the high thermal efficiency and low carbon dioxide emission, the usage of a diesel engine is prevailed. In this study, the DC non-thermal plasma technology used to the particulate matter (PM) aftertreatment. The exhaust gas characteristics and energy density were investigated on the dynamometer test bed and chassis dynamometer with CVS-75 mode in a passenger diesel car. It was reported that the smoke removal efficiency has around the 70% in the dynamometer test with 80W energy consumption and the PM removal efficiency has the 68% in the real car test. The NOx also reduced the 20% according to electrode type respectively. Considering these results, plasma technology is one of the ways to simultaneously removing method the particulate matter (PM) and NOx.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.3
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• pp.229-236
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• 1998

Visibility is a good indicator of comprehensive alto quality. The prevailing visibility in Seoul is no better than the past although the average concentration of SO2 and TSP (total suspended particulate) has decreased quite significantly in the past decade, owing to the government efforts to reduce the emission. Then, a question arises why visibility has not been improved. In order to answer this question we have investigated which components of air pollutants are most responsible for the visibility degradation in Seoul. Analysis on the visibility vs the aerosol sixte distribution measured by an optical particle counter shows that the particles of the size interval between 0.5mm and 2.5mm are most responsible for the visibility degradation. Among the criteria air Pollutants, NOB concentration is found to be moot responsible, rather than PM10. ton analysis of the particulate collected by a high volume sampler shows that the nitrate component increases more significantly than other ions when visibility becomes very poor. Therefore, we conclude that the major causes of visibility degradation in Seoul are the increase of NOB, nitrates and the particles of the size range between 0.5mm and 2.5mm.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.5
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• pp.58-65
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• 1994

In order to reduce particulate emissions from diesel vehicles, mathematical model is established and analyzed on ceramic wall-flow monolith filter. A wall-flow monolith filter placed in the exhaust stream of a diesel engine can effectively limit the emission of diesel particulates through the monolith. The accumulated particulates can then be periodically combusted inside the monolith by directing hot gas to the monolith while normal engine exhaust is routed around the monolith system. The resulting low flow rates through the monolith require consideration of gas dynamics through the channels as well as particulate combustion to analyze this regeneration process. A mathematical model of the regeneration is formulated as a system of nonlinear partial differential equations describing the conservation of mass, momentum and energy. Numerical solutions are obtained by using a finite difference techniques for the spatial discretization. So we can use filter simulation program for the purpose of filter design and actual filter regeneration

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.6
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• pp.623-632
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• 2015

This study proposes a control strategy of the common rail pressure with a fuel injection limitation algorithm to reduce particulate matter (PM) emissions under transient states. The proposed control strategy consists of two parts: injection quantity limitation and rail pressure adaptation. The injection limitation algorithm determines the maximum allowable fuel injection quantity to avoid rich combustion under transient states. The fuel injection quantity is limited by predicting the burned gas rate after combustion; however, the reduced injection quantity leads to deterioration of engine torque. The common rail pressure adaptation strategy is designed to compensate for the reduced engine torque. An increase of the rail pressure under transient states contributes to enhancement of the engine torque as well as reduction of PM emissions by promoting atomization of the injected fuel. The proposed control strategy is validated through engine experiments. The rail pressure adaptation reduced the PM emission by 5-10% and enhanced the engine torque up to 2.5%.

• Nuclear Engineering and Technology
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• v.36 no.5
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• pp.450-459
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• 2004

For the evaluation of emission sources by air sampling, airborne particulate matter for fine (<2.5 ${\mu}m2$ EAD : $PM_{2.5}$) and coarse partical (2.5-10 ${\mu}m2$ EAD : $PM_{2.5-10}$ fractions were collected using a Gent stacked filter unit low volume sampler and two types of polycarbonate filters. Air samples were collected twice monthly at two regions in and around Daejeon city in the Republic of Korea from January to December 2002. Monthly mass concentration of $PM_{2.5}$ and $PM_{2.5-10}$ were measured and the concentrations of 10 marker elements (Al, Sc, Ti ; Na, Cl ; As, V. Sb, Br, Se) were determined by an instrumental neutron activation analysis. Analytical quality control was corried out using certified reference materials. Enrichment factors were also calculated from the monitoring data to classify the anthropogenic and crustal origins.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.3
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• pp.276-285
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• 2010

Recently the Korean government has tried to cut down the $PM_{10}$ concentration by the Special Law for Air Quality Improvement. But the concentrations of $PM_{10}$ have exceeded the air quality standard at most monitoring stations. Primary $PM_{10}$ emitted from various sources and emission data have large uncertainty. The biomass burning is one of the major sources of $PM_{10}$ emission. The biomass burning is composed of wood stove usage, meat cooking and agricultural combustion etc.. Activity data and emission factors for the biomass burning are limited, and it is hard to calculate the air pollution emissions from these sources. In this study, we tried to estimate the air pollution emission from residential wood stove usage. The number of total wood stoves is estimated by the survey of wood stove manufacturer. And air pollution emission factors for the wood stove are investigated using the flue gas measurement by U.S. EPA particulate test method (Method 5G). As the results, the $PM_{10}$ and CO emission factors of wood stove are estimated as 7.7 g/kg-wood and 78.8 g/kg-wood respectively. The annual $PM_{10}$ and CO emissions from wood stove are calculated as 1,200~3,600 ton/year and 12,600~36,400 ton/year in Korea. It is confirmed that wood stove is the one of major sources of biomass burning, and the survey for activity data and the measurement for emission factors are needed for reducing the uncertainty of these emission data.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.104-109
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• 2006

Improvements in internal combustion engine and aftertreatment technologies are needed to meet future environmental quality goals. Plasmatron fuel converters provide a rapid response, compact means to transform a wide range of hydrocarbon fuels (including gasoline, natural gas and diesel fuel) into hydrogen-rich gas. Hydrogen-rich gas can be used as an additive to provide NOx reductions of more than 80% in diesel engine vehicles by enabling very lean operation or heavy exhaust engine recirculation. For diesel engines, use of compact plasmatron reformers to produce hydrogen-rich gas for the regeneration of NOx absorber/absorbers and particulate traps for diesel engine exhaust after-treatment could provide significant advantages. Recent tests of conversion of diesel fuel to hydrogen-rich gas using a low current plasmatron fuel converter with non-equilibrium plasma features are described.

• Journal of the Korean Ceramic Society
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• v.45 no.9
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• pp.497-506
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• 2008

The long time of twenty years has passed since Diesel Particulate Filter (DPF) was proposed before the practical use. The main factors that DPF has been put to practical use in this time, are the same time proposal of the evaluation method of SiC porous materials linked to he performance on the vehicle, and that the nature of thermal shock required for the soot regeneration (combustion of soot) in the DPF is different from the conventional requirement for the rather rapid thermal shock. For the requirements, these includ demonstrating utmost the characteristic of SiC's high thermal conductivity, and overcoming the difficulty of thermal expansion of SiC-DPF by dividing the filter into segments binding with the cement of lower Young's modulus, and the innovation of technology around the diesel exhaust system such as Common-Rail system. As the results of these, the cumulative shipments of SiC-DPF have reached about 5 million, and it goes at no claim in the market.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.138-142
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• 1998

Among aftertreatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now being studied actively. In this study, an experiment was conducted to analyze the effects of low sulfur diesel fuel in heavy duty diesel engine equipped with DOC. We tested to estimate change of engine performance for the low and high sulfur diesel fuels in a 11,000cc diesel engine equipped with DOC. We conducted test to estimate the reduction efficiency of exhaust gas in D-13 mode of heavy duty diesel regulation mode and in smoke opacity mode for two samples of high sulfur content (0.2%) and low sulfur content(0.05%)

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.20-27
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• 1999

The proportion of diesel vehicle is very high in this country . PM and NOx emitted from diesel-posered vehicle is severely ;affecting to be air quality . Especially, diesel particulate matters(DPM) including black smoke are hazardous air pollutants to human health and environment. In order to reduce the exhaust emissions from diesel engines, it is necessary to analyze the characteristics of exhaust emissions from diesel engines in various driving conditions. Recently, there are occasion to increase the fuel consumption rate to engine power up. So, in this study we have tested a diesel engine detached from in use -diesel vehicle and analyzed exhaust emission by driving condition and fuel dispersion rate. From this results, we will prepare the comprehensive management plan for exhaust emissions from diesel vehicles and contribute to the improvement of air pollution in urban area.