• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4729-4735
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• 2014

To protect the environment, the regulation of emissions from off-road engines which are relatively neglected, is being reinforced. This paper deals with the robust design of off-road diesel engines considering the emission characteristics. Measurements of the NOx and PM levels based on the DOE were carried out. The injector hole number, injection timing and EGR rate were selected as the control factors. The orthogonal arrays table $L_9(3^3)$ was made from 2 or 3 levels for each factor and measurements of emissions were accomplished based on the table. The small-the-better SN ratio according to the Taguchi method was evaluated. The ANOVA (analysis of variance) for the SN ratio was conducted. The injection timing on the NOx emissions and the EGR rate on the PM have the largest effect on the low-load operation condition. The confidence levels of the control factors were more than 90%.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.447-448
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• 2003

SOx 등과 함께 대기오염 발생에 가장 크게 관여하는 NOx를 제거 하고자 오래전부터 지금까지 많은 연구가 수행되어 왔다. NOx가 배출되는 유형에 따라 발전소, 보일러 및 산업체와 같은 고정원에서 배출되는 경우와 자동차나 선박과 같은 이동원에서 배출되는 두 가지의 경우가 있다. 고정원에서 NOx를 제거하는 가장 효율적인 방법은 암모니아에 의한 NOx의 선택적 제거법(Selective Catalytic Reduction)으로 알려져 있다. (중략)

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.3
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• pp.16-25
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• 2003

In this paper, the reduction of green house effect gas CO₂ emission and NOx gas emission by using the RORO ship coastal transport of import-export container cargo was investigated. At first, the domestic CO₂ gas emission and the transportation of import-export container cargo were Investigated. Next, the characteristic of a RORO ship and CO₂ emission standard and NOx emission standard were investigated. And also, the reduction of CO₂ emission and NOx emission by the shift of coastal transport from land transport for the transportation of import-export container cargo between Kyongin area and Pusan Port were calculated. Finally, the change of CO2 and NOx gas emission due to the change of the share of coastal transportation and the load efficiency of RORO ship are investigated. The research results show that the shift of RORO ship coastal transport from land transport was very effective to reduce the CO₂ emission but it was no good to reduce the NOx emission.

• Journal of Advanced Marine Engineering and Technology
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• v.25 no.3
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• pp.471-486
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• 2001

The principal trends in the course of emission control legislation are reviewed in this paper. In order to keep such a regulation, moreover, an inquiry ito the concrete technical possibility is conducted through review articles, Also, the composition of exhaust gases emitted from a marine diesel engine are investigated as several samples and the measures that can satisfy the value of regulation are handled with laying stress on the control methods discussed to date. It was concluded that various combined systems can be made to reduce NOx emissions without deteriorating substantially navigation costs since many technologies for reducing NOx emissions are being developed. All heat engines suffer from SOx emissions. There are two methods for reducing SOx emissions: desulfurization from exhaust gas and removal of sulfur composition from fuel oil. However it is necessary to watch the development of these technologies to evaluate which method is more favorable. Heat engines have a big problem in the regulation of environmental pollution from exhaust emissions. In the near future, however, diesel engines may be superior to other heat engines, owing to the high thermal efficiency, although the sales of individual models in dises engines may be prosperous and declining.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.1
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• pp.76-88
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• 1995

The effects of exhaust gas recirculation(EGR) on the characteristics of NOx emissions and specific fuel consumption rate have been investigated using an eight-cylinder. four cycle. direct injection diesel engine operating at several loads and speeds. The theoretical NO formation concentration is calculated with the equivalence ratio as a parameter of flame temperature to study the effect of EGR on NOx emissions in the diesel combustion. The experiments in this study are conducted on the fixed fuel injection timing of $38^{\circ}$ BTDC regardless of experimental conditions. It is found that the specific fuel consumption rate is slightly increased with EGR rate. and NOx emissions are markedly reduced owing to the drop of the incoming oxygen concentratio and the increase of equivalence ratio as the EGR rate increases.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.10
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• pp.637-644
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• 2016

The purpose of this study is to understand the characteristics of unburned carbon (UBC) and NOx emissions for pulverized coal when air staging combustion is applied. A two-staged drop tube furnace capable of applying air staging combustion was designed and installed. The combustion of sub-bituminous (Tanito) has been investigated. UBC and the NOx concentration were measured under various temperatures and stoichiometric ratios in unstaged and staged combustion. As a result, UBC decreased and the NOx concentration increased with an increase in stoichiometric ratio and temperature. In particular, the NOx reduction mechanism was activated when the temperature in the fuel rich zone increased. Both UBC and the NOx concentration decreased as the temperature increased in the fuel rich zone. A high NOx reduction effect was obtained, compared to the UBC increase, when the air staging technique was applied.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.3
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• pp.307-312
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• 2002

A study on the exhaust emissions of marine diesel engine with various fuel injection timing is performed experimentally .In this paper, fuel injection timing is changed from BTDC $14^{\circ}$ to $20^{\circ}$ by $2^{\circ}$ intervals, the experiments are performed at engine speed 1800rpm and from load 0% to 100% by 25% intervals, and main measured parameters are fuel consumption rate, Soot, NOx, HC and CO emissions etc. The obtained conclusions are as follows (1) Specific fuel consumption is indicated the least value at BTDC $18^{\circ}$ of fuel injection timing and it is increased in case of leading the injection timing. (2) Soot emission is decreased in case of leading fuel injection timing and it is increased in the form of convex downwards with increasing the load. (3) NOx emission is increased in case of leading fuel injection timing and it is increased in the form of straight line nearly with increasing the load. (4) HC and CO emissions are decreased in case of leading fuel injection timing and they are changed in the form of convex downwards with increasing the load.

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.255-261
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• 2007

The catalytic behavior of the manganese oxides was studied for the selective catalytic reduction with ammonia at a low temperature condition under $200^{\circ}C$. Outlet unreacted ammonia increases with decreasing temperature and increasing $NH_3/NOx$ mole ratio, however $NO_2$ shows an opposite result. $NO_2$ is generated by the adsorption of NO on the catalyst and the following oxidization to nitrates. Unreacted NH3 slip is not observed even at the $NH_3/NOx$ feed ratio above 1.0 due to the reaction between formed nitrates on the catalyst and adsorbed ammonia. The addition of Zr increases $NO_2$ generation, whereas the addition of CeO2 on the catalyst decreases $NO_2$ generation. Furthermore, the additon of the metal oxide induce DeNOx efficiency to reduce.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.21-22
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• 2006

디젤엔진에서 배출되는 배기가스 중의 주요 오염물질 중의 하나인 NOx(질소산화물)는 대부분 고온의 연소 과정에서 발생하고, 발생량은 연소온도에 따라 결정되는 것으로 알려져 있다. 또한 연료의 연소 중에 물이 첨가되면 연소공기의 비열 증가에 의하여 연소온도가 감소하여 NOx 발생량이 급격하게 감소하게 되는데, 연소실에 물을 첨가하는 방법으로는 유화연료, 직접물분사, 흡기가습 등이 있다. 이중 흡기가습은 구조가 간단하면서 NOx 저감효율이 가장 높은 것으로 알려져 있다. 본 연구는 당사 고유모델 중형엔진인 힘센엔진에 흡기가습 기술을 적용하여 연소성능 및 NOx 저감효과 등을 시험하고, 흡기가습 시스템의 상용화 모델 개발을 위한 기초 데이터를 확보하기 위해 수행되었다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.180-188
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• 1992

By means of the compatibility according to solving environmental pollution and energy problem due to the emissions of NOx and smoke from diesel engine this paper experimentally inspected the effect of using emulsified fuel, gas oil-water, for combustion characteristic, that is combustion pressure, pressure rise rate, heat generating rate, the period of ignition delay and specific fuel consumption, and CO, HC, NOx concentration and smoke density. When using emulsified fuel, as a water addition rate was increased, combustion pressure, pressure rise rate and heat generating rate was increased, the period of ignition delay was lengthening, the specific fuel consumption was some what increased in contrast to diesel fuel in low load, but deceased in high load region. And NOx concentration was decreased, CO concentration was increased in low load, but decreased in high load region, HC concentration was increased in contrast to diesel fuel in all region.