• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.2
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• pp.177-182
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• 2015

The NOx emissions from diesel engines and industrial boilers are a major cause of environmental pollution. The selective catalytic reduction of urea is an aftertreatment technology that is widely used for the reduction of NOx emissions. The objective of this study was to investigate the characteristics of the thermal decomposition of a urea aqueous solution using laboratory-scale experimental equipment under conditions similar to those of marine diesel engines. A 40 wt. urea aqueous solution was used in this study. It was found that the total conversion rate varied with the inflow gas conditions and flow rates of the urea aqueous solution. In addition, there were conversion rate differences between NH3 and HNCO. At inflow gas temperature conditions of $210^{\circ}C$ and $250^{\circ}C$, the $NH_3$ conversion rate was found to be higher than that of the HNCO, depending on the residence time.

• Journal of Energy Engineering
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• v.18 no.1
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• pp.31-36
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• 2009

There are several types of environment friendly vehicle being developed by auto manufactures. HEV (Hybrid Electric Vehicle) is most applicable one among them in actuality. HEV has two power sources, one is an internal combustion engine, the other one is an electric device. The HEV is developed for reducing fuel consumption and emissions. We selected the diesel engine as a main power source of HEV. The tests were carried out under different driving cycles which was CBDBUS (Central Business Driving Bus Schedule) and HWFET (Highway Fuel Economy Test). This research presents a simulation for the fuel economy and the emission of heavy diesel hybrid vehicle according to the SHEV (Serial Hybrid Electric Vehicle), PHEV (Parallel Hybrid Electric Vehicle), Plug-in SHEV and plug-in PHEV.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.7-14
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• 2002

In order to reduce exhaust omissions of spark ignition engine, it is important not only to improve catalyst conversion efficiency but also to directly reduce engine out exhaust emissions, during cold starting and warm up process. Therefore many researchers have been attracted to develop an early fuel evaporator(EFE) by Introducing a ceramic heater fur a solution of engine out exhaust emissions in SI engine. But, the performance of the EFE in MPI engine to reduce the exhaust emissions and to improve the cold startability has not been clarified yet. The purpose of this study is to evaluate the feasibility of a glow plug far EFE. Impinging spray using heated and unheated glow plug helps the vaporization of the fuel and heat up the three way catalyst sufficiently. The amount of CO, and UHC is reduced overall. The amount of NOx is higher at the initial stage, but become lower as time goes on than without glow plug.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.626-631
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• 2019

The policy-making and technological development for the supply expansion of eco-friendly automobiles has been continuing, but the internal combustion engines still accounts for about 95%. Also, in order to meet the stricter emission regulations of internal combustion engines based on fossil fuels, the proportion of after-treatments for vehicles and (ocean going) vessels is gradually increasing. This study is a basic study for the post-Euro-VI exhaust response of CNG buses, and it is to investigate the basic characteristics according to Pd substitution transition metal effect, catalyst volume effect and space velocity. A catalysts was prepared and tested using a model gas reactor. The NGOC catalyst with 3Pd exhibited the highest catalytic activity with 22% at $300^{\circ}C$, 48% at $350^{\circ}C$ and about 75% at $500^{\circ}C$. 3Co NGOC containing 3wt% of transition metal was excellent in oxidation ability, and it was small in size of 2nm, and the degree of catalyst dispersion was improved and de-NO/CO conversion was high. The volume of the NGOC-LNT-SCR catalyst system was optimal in the combination of 1.5+0.5+0.5 with a total score of 165, considering $de-CH_4/NOx$ performance and catalyst cost. For SV $14,000h^{-1}$, the $CH_4$ reduction performance was the highest at about 20%, while the SV $56,000h^{-1}$ was the lowest at about 5%. If the space velocity is small, the flow velocity decreases and the time remaining in the catalyst volume become long, so that the harmful gas was reduced.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.526-530
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• 2009

본 연구은 자동차용 가솔린엔진에 장착되는 인젝터의 연료공급 특성에 대한 것으로, 가솔린 엔진의 전자제어식 포트 연료분사는 분무장치와 흡기포트의 최적화 및 분무특성이 우수해야 엔진의 성능 향상 및 배기가스 저감의 목적을 이룰 수 있다. 4홀과 12홀 인젝터의 장착각 변화와 포트 마스킹의 형상변화에 따른 벽유량을 측정?분석하였고 분무가시화 실험을 통하여 분무성장과정과 분사각, 연료미립화 및 분무도달거리를 분석하였다. 벽류측정 실험을 통하여 벽류는 미립화정도와 흡기유동과 유속에 가장 큰 영향을 받는 것으로 판단되며, 12홀 인젝터 대비 4홀 인젝터는 분무압력에 따라 분무특성의 변화량이 크게 나타났다.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.179-189
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• 1997

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 studied actively. In this study, a transient one-dimensional model developed to simulate the thermal and conversion characteristics of adiabatic monolithic converters operating under warm up conditions is presented. This model takes into account the gas solid heat and mass transfer, axial heat conduction, chemical reactions and the related heat release. The model has been used to analyze the transient response of an axisymmetric catalytic converter during a warm-up as a function of catalyst design parameters and operation conditions in order to observe their effects on the lightoff behaviour. The experimental test was carried out 2400 cc light diesel engine with DOC.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.136-142
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• 2000

With the significant growth of the number of vehicles environmental problems is raised. NOx SOx, and PM emissions in diesel powered vehicles are larger than that in gasoline because the development of pollutants reduction techniques has not been yet achieved. So it is need to develop after-tratment or to convert into alternative fuel to satisfy emission regula-tion. Among the after-treatment systems to reduce the diesel emissions studies with diesel oxidation catalyst(DOC) are done greatly. In this study using DOC reduction efficiency with the change of temperature and catalyst loading was calculated through measurements of CO, HC, PM. and SOX.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.151-152
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• 2012

Collectors connected to diesel engine exhaust pipe for application of PM reduction facilities which was used to reduce PM from the exhaust gas produced from ship, Filtration performance of PM was tested. In this system, it was confirmed that the bag house can remove over 90 percent of PM from a lot of high temperature and high pressure gases produced in diesel engine. The results obtained from performance test show the potential possibility for commercialization of ceramic filter collectors which is applied to reduction facilities of flue gas produced from a diesel engine on the ship.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.2
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• pp.207-218
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• 2017

Improving fuel consumption, particularly that of commercial vehicles, has become a global concern. The reduction in logistics cost has been a key issue in efforts to improve fuel economy and efficiency of transportation equipment. Typical technologies for reducing reduce fuel usage include air resistance reduction technologies, tire rolling resistance technologies, and idle technologies among others. Air resistance technology is a highly effective method that can be easily applied in a short period. As with air resistance technology, several devices involving side skirt, boat tail and gap fairing have been developed based on an analytical 3-D modeling technique for reducing air resistance attributed to the vehicle configuration. The devices were on a 45 feet tractor-trailer and the emission test was done using PEMS equipment. Fuel economy was evaluated by introducing several devices to reduce outer air resistance. The test was conducted by changing the experimental method of SAE J1321 Joint TMC/SAE Fuel Consumption Test Procedure - Type II test. As a result, air resistance decreased by at least 15 % and fuel economy improved by at least 13 %. This study sought to reduce greenhouse gas and improve fuel economy by applying several devices to a test vehicle to lower air resistance.

• Journal of the Korean Institute of Gas
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• v.19 no.3
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• pp.1-8
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• 2015

In this study, we performed risk assessment of chloroprene by hazard evaluation and workplace investigation. The chemical is used to manufacture of shoes, tires, adhesives, and classified as IARC category 2B (possibly carcinogenic to humans) and target organ systemic toxicity. It is used about 1,300 tons per year in 27 sites. It was calculated the risk of carcinogenesis with chloroprene by Monte-carlo simulation that the averages are 2,199 and 26,404 in each case of working less than 15 minutes per day with local exhaust ventilation and over 4 hours per day without local exhaust ventilation. The risk of target organ systemic toxicity are 4.10 and 169.06 with high correlation with working time to be longer and with ventilation system. Therefore, it is recommended that the local exhaust ventilation and respirators to prevent occupational cancer and target organ systemic toxicity with chloroprene. Especially it is determined that there is a need to strengthen the workplace exposure limit (TWA 10 ppm) in Korea since it is managed with TWA less than 5 ppm ($18mg/m^3$) by the United States Occupational Safety and Health Administration (OSHA) as well as it has carcinogenicity, reproductive toxicity.