• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.45-51
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• 2015

In order to meet the enforced emission regulations and reduce fuel consumption, various new technologies are employed in engines. The problem of NOx emissions under a lean mixture condition should be solved, because a lean-burn direct-injection engine can realize stable lean combustion with a stratified mixture, which results in improvements in fuel economy and emissions. This study investigated the effects of intake and exhaust valve timing changes on the performance and emission characteristics of a lean-burn LPG direct-injection engine. Under a partial-load operating condition without throttling, an increase in the intake valve opening led to an increase in NOx emissions due to an increase in the amount of excess air. The fuel consumption deteriorated with an increase in the exhaust valve opening due to a decrease in the expansion work and an increase in the pumping loss.

• Journal of Korea Port Economic Association
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• v.32 no.4
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• pp.15-28
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• 2016

Port of Busan is Korea's largest trading port processing over 18,000 TEU a year. This rapid growth causes air pollution problems in Busan. Ship emissions are significant air pollution sources and port area is relatively close to the business district, therefore it may have serious effects to the health of local people and environment. In this study, ship emissions are estimated, especially on hotelling large vessels. As a result, Port of Busan has 50,686, 48,842 ship calls and 2,343,037 and 2,297,118 tons of ship emissions in 2011 and 2012 respectively. Also, the environmental cost in Port of Busan is approximately 1.2 trillion won per year. This study emphasizes the necessity of ship emissions regulation, hence, it is expected to make a significant contribution in setting up ship emission management system.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.130-138
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• 2015

Despite of recently strengthened vehicle emission regulations, NOx emissions are not decreased in urban areas because of discrepancies between certification emission test modes and real driving conditions. Thus, researches on RDE-LDV (Real-driving Emission-Light-duty Vehicle) have been conducted actively using PEMS (Portable Emissions Measurement Systems). In the present study, NOx emissions were measured for 5 Korean light duty vehicles for real driving conditions including city, combined, highway, and up-downhill test route. Emission characteristics were analyzed for averaged NOx emissions per unit driving distance of each driving test routes. Furthermore, MAW (Moving Average Window) method based on $CO_2$ emissions from WLTC, which will be supported for EU regulations, was utilized. It was revealed that DRs (deviation ratios) for diesel vehicles (i.e., 5.1 ~ 8.4) were greater than gasoline vehicles (less than 0.15). Especially DR of diesel vehicle for up-downhill test route was 8.4, which indicates severe NOx emissions.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.6
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• pp.629-634
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• 2010

Natural gas is a promising alternative fuel that can be used to satisfy the strict engine emission regulations in many countries. To develop natural-gas engines, low emission, efficient fuel consumption, and increased power ratings have to be realized. In this study, a cylindrical constant-volume combustion chamber (CVCC) was used to investigate natural-gas combustion characteristics for different prechamber design parameters and equivalence ratios. In particular, the maximum combustion pressure and mass fraction of the burned gas were evaluated by considering orifice diameter, volume ratio of prechamber and equivalence ratio. Using this result and by analyzing the changes in combustion characteristics with variations in design parameters, the optimum prechamber parameters were determined.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1993.04a
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• pp.20-31
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• 1993

최근 엔진유 등 자동차용 윤활유를 비롯한 윤활유 제품에 요구되는 성능은 이전과 비교할 수 없을 정도로 고도화 및 다양화되어가고 있다. 그 중에서도, 환경보호, 에너지절감, 배기가스규제 등 환경과 관련된 성능의 개선이 절실한 실정이다. $CO_2$ 가스의 증가에 기인되는 지구온난화에 대한 관심이 세계적으로 높아지고 있으며, 산성비에 의한 환경파괴도 문제화되어 있다. 본고에서는 환경 및 에너지 절감과 관련된 윤활유의 요구성능과 제품개발의 동향에 관하여 엔진유를 중심으로 소개한다.

• Journal of the korean Society of Automotive Engineers
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• v.26 no.3
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• pp.39-43
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• 2004

최신의 엔진기술과 배기 후처리 기술만으로는 앞으로 더욱 엄격해질 일본의 신장기 규제치(2005년)를 만족시키기에 한계를 느끼기 시작함으로서 배출가스 저감에 보다 효과적인 대응책이라고 할 수 있는 연료설계가 주목을 받고 있다. 그 대표적인 예로서 천연가스, 석탄 및 바이오 물질을 이용해 제조가 가능한 GTL(Gas to Liquid), DME(Dimethyl Eter) 및 바이오 연료는 석유의 대체연료 뿐만 아니라 유황 및 방향족 성분이 매우 낮은 저공해 연료로도 일본 내에서 연구가 활발히 이루어지고 있다. (중략)

• Journal of the korean Society of Automotive Engineers
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• v.18 no.2
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• pp.103-109
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• 1996

근래 들어 석유 에너지에 대한 대체 에너지 개발을 위한 노력이 여러 분야에서 활발하게 이루어지고 있다. 이는 석유 자원의 고갈에 대한 대비라기 보다는 전세계적으로 심각해져가고 있는 환경오염이라는 보다 더 심각한 문제에 대한 대처로서 인식되어져 가고 있다. 1992년 6월에 열린 지구환경 정상 회담 결과 자동차 배출가스규제 기준의 국제협약화가 예상되고 있으며 EC등은 이산화탄소 세금이라고 불리우는 환경세 도입의 압박을 가해오고 있다. 당사는 기존의 자동차연료인 가솔린이나 경유에 비해 유해배기 물질을 현저히 줄일 수 있는 대체 에너지를 사용하는 자동차의 개발을 위해 많은 노력을 기울이고 있는데, 본 논문에서는 천연가스자동차와 전기자동차를 중심으로 당사의 개발현황을 소개하겠다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.162-163
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• 2018

A risk assessment is performed at the initial design stage of LNG-fuelled ships subject to new fuel supply systems due to marine environmental and emissions regulations. Risk assessment involves a series of logical steps that enable systematic risk analysis and evaluation. LNG-fuelled ships mainly consist of a tank for storing LNG, a gas supply unit for supplying LNG to the engine, an engine using LNG as fuel, and a bunkering manifold for receiving LNG. The components of the LNG fuelled ship are determined according to the characteristics, size, rout, and operating distance. Therefore, the risk factors of each ships are different, and the risk analysis also changes. In this study we consider the systems of ships using LNG as a fuel and analyze the risk assessment of certain cases where the actual risk assessment has been carried out.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.407-412
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• 2003

지구환경보존이 세계적인 과제로 되어있는 오늘날 디젤엔진으로부터 배출되는 배기배출물에 대한 문제가 대두되고 있으며, 미국의 캘리포니아주(CARB)에 있어서는 세계최초로 농업기계용 엔진을 포함한 운송용 엔진에 대하여 엄한 배기가스 규제법안을 세워 시행중에 있다. 또한 전미, 유럽 및 일본에 동일한 검사가 이루어지고 있는 실정이다. 따라서, 디젤엔진으로서 문제가 되고 있는 배기성분인 NOx와 파라큘레이트(PM)에 대한 저감대책으로 최근 고압분사(HSDI), EGR 및 후처리(De-NOx) 촉매등의 연구가 시행되고 있으며, 전망이 기대되어지고 있다. 그러나 경제성, 내구성, 제품의 크기, 차량의 중량증가 등이 과제로 남겨지고 있다(유강택 외 1997). (중략)

• Clean Technology
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• v.26 no.1
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• pp.22-29
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• 2020

Recently, as the fine dust is increased and the emission regulations of diesel engines have been tightened, interest in diesel soot filtration devices has rapidly increased. There is specifically a demand for the technological development of higher diesel exhaust gas after-treatment device efficiency. As part of this, many studies were conducted to increase exhaust gas treatment efficiency by improving the flow uniformity of the exhaust gas in the diesel particulate filter (DPF) and reducing the pressure drop between the inlet and the outlet of DPF. In this study, the effects of pressure drop by the flow rate and temperature of exhaust gas, DPF I/O ratio, Ash, and PM amount in diesel reduction device were simulated via a 12" diameter DPF and diesel oxidation catalyst (DOC) using ANSYS Fluent. As the flow rate and temperature decreased, the pressure drop decreased, whereas the PM amount affected the pressure drop more than the ash amount and the pressure drop was lower in anisotropic DPF than isotropic DPF. In the case of DPF flow uniformity, it was constant regardless of the various variables of DPF. In ESC and ETC conditions, the filtration efficiency for PM was similar regardless of anisotropic and isotropic DPF, but the filtration efficiency for PN (particle number) was higher in anisotropic DPF than isotropic DPF.