• 전기학회논문지
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• 제58권5호
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• pp.968-975
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• 2009

The goals of this research are to understand the regeneration characteristics in diesel particulate filter using the HC injection. This research emphasized on the development of Continuously Regenerating DOC/DPF and HC technology which was the best particulate matters removing technology of current existing technology. This experimental study has been conducted with equipped a Continuously Regenerating DOC/DPF and HC injection on displacement 2.0, 3.3 $\ell$ diesel engine and compared in terms of particulate material and emission. In this study, we could constructed 3 kinds of database according to quantity of temperature to decide the HC injection quantity and develop DOC/DPF ECU algorithm.

• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2164-2171
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• 2018

Heavy duty diesel vehicles deteriorate urban air quality by discharging a large volume of air pollutants such as soot and nitrogen oxides. In this study, a newly introduced auxiliary device a fuel activation device (FAD) to improve the combustion efficiency of internal engines by utilizing the cavitation effect was closely investigated by the fluid flow mechanism via a numerical analysis method. As a result, the FAD contributed to fuel atomization from the injection nozzle at lower inlet pressure by reducing the pressure energy. The improved cavitation effect facilitated fuel atomization, and ultimately reduced pollutant emission due to the decrease in fuel consumption. The axial velocity along the flow channel was increased 8.7 times with the aid of FAD, which improved the primary break-up of bubbles. The FAD cavitation effect produced 1.09-times larger turbulent bubbles under the same pressure and fuel injection amount than without FAD.

• 한국자동차공학회논문집
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• 제14권4호
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• pp.39-48
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• 2006

In this research, in order to study the spray, combustion, and emission characteristics of the common rail DME engine, the target engine was disassembled, and 3D CAD file was constructed using a 3D measurement machine and a rapid prototyping machine. Using the obtained 3D geometry, fine moving meshes are generated, and three dimensional non-steady turbulence flow field and combustion phenomenon including spray were numerically analyzed. As a result, IMEP of DME and diesel in medium and high speed revolution showed similar performance. As the DME fuel start to burn in spray area, the vaporized fuel rapidly spreads squish area in low speed revolution. In the case of DME engine, CO and NOx are relatively consistent with experiment results. It was found that the break-up, evaporation, collision model of DME fuel need to be properly adjusted through matching the characteristics of fuel and injector for further improvement.

• 대한기계학회논문집B
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• 제36권4호
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• pp.371-376
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• 2012

본 연구에서는 대형버스 배기가스 테스트 모드인 JE-05 에서 DME와 디젤을 연료로 사용하는 대형 DME버스를 차대동력계, 배기가스 분석기 그리고 PM 측정시스템을 이용하여 대형 DME버스의 연비, 배기가 스특성 그리고 동적 특성에 대해 알아보았다. 대형 DME버스에는 6기통 8,071cc 디젤엔진이 장착되었으며, 현재 운행되고 있는 상용 디젤버스와는 달리 DOC, DPF와 같은 후처리 장치가 없다. 실험 결과, 각 부하에 따른 차량의 속도를 통하여 차량의 동적 특성은 DME와 디젤을 사용했을 때 거의 비슷한 것을 알 수 있었다. NOx, CO와 THC는 DME를 연료로 사용 시 디젤연료에 비해 더 적게 배출되는 것을 확인하였다. 하지만 PM은 DME연료를 사용 시 거의 발생하지 않았는데, 이는 DME가 함산소연료이고 분자구조상 탄소-탄소 결합이 없기 때문이라고 생각된다. $CO_2$는 각 연료 사용 시 비슷하게 발생하였으며, 저위발열량 베이스로 계산된 연비는 DME연료 사용 시 디젤연료보다 약 6.7% 더 낮게 나왔다.

• International Journal of Automotive Technology
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• 제6권4호
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• pp.333-340
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• 2005

In order to better quantify the contribution from nonroad sources to emission inventories, it is important to understand not only the emissions rates of these engines but also activity patterns that can be used to accurately portray their in-use operation. To date, however, very little information is available on the actual activity patterns of nonroad equipment. In this study, a total of 18 pieces of nonroad equipment were instrumented with collected data including intake manifold air pressure (MAP), exhaust temperature and, on a subset of vehicles, engine rpm and throttle position. The equipment included backhoes, compactors, dozers, motor graders, loaders and scrappers used in applications such as landfilling, street maintenance and general roadwork. The activity patterns varied considerably depending on the type of equipment and the application. Daily equipment operating time ranged from less than 30 minutes to more than 8 hours, with landfill equipment having the highest daily use. The number of engine starts per day ranged from 3-11 lover the fleet with an average of 5 starts per day. The average percent idle time for the fleet was approximately $25\%$ with a range from 11 to $65\%$ for individual pieces of equipment. Duty cycles based on exhaust temperature/throttle position profiles were also developed for two graders and one dozer.

• 농업과학연구
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• 제37권3호
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• pp.501-508
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• 2010

A swirl chamber type diesel engine attachable to 18 kW agricultural tractors was improved to reduce exhaust emissions. Compression ratio and throat area ratio of the combustion chamber were varied to determine optimum combustion conditions. Tests were composed of full load and 8-mode emission tests. Compression ratio was fixed as 21, but the swirl chamber volume was increased by 3.8%. Output power, torque, specific fuel consumption, exhaust gas temperature, and smoke level were not considerably different for compression ratios of 21.5 (reference condition) and 21 (test condition), while NOx, HC, CO and PM levels for the compression ratio of 21 were decreased by 11%, 46%, 28%, 11%, respectively, from those for the compression ratio of 21.5. The tests were also conducted with a compression ratio of 22 and 4.3% increased chamber volume. Output power, torque, exhaust gas temperature and smoke level were greater, while specific fuel consumption was less for the compression ratio of 22 than those for the compression ratio of 21.5. Increase of compression ratio decreased HC and CO levels by 24%, 39%, but increased NOx and PM levels by 24%, 39%. Based on these results, a compression ratio of 21 was selected as an optimum value. Then, full load tests with the selected compression ratio of 21 were carried out for different throat ratios of 1.0%, 1.1%, 1.2%. Output power and torque were greatest and smoke was lowest when throat area ratio was 1.1%, which satisfied the target values of specific fuel consumption (less than 272 g/$kW{\cdot}h$) and exhaust gas temperature (less than $550^{\circ}C$). Therefore, a throat area ratio of 1.1% was selected as an optimum value.

• 한국자동차공학회논문집
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• 제15권6호
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• pp.17-22
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• 2007

GTL(Gas-to-Liquids) fuel technology was converted from the natural gas, coal and biomass into the diesel or kerosene by Fisher-Tropsch synthesis. GTL fuel have very good merits on high cetane number, low density, free sulfur, lower aromatics contents and no poly-aromatic hydrocarbons as well as the autoignition characteristics. These physical properties make it valuable as a diesel fuel with lower emissions than the conventional diesel fuel. Furthermore, GTL fuel can be use not to the engine any modification. Therefore, to evaluate emissions of GTL fuel, the tested diesel vehicles were fueled on blends of GTL fuel/ultra low sulfur diesel fuel(ULSD). And then, we found out that GTL fuel reduced regulated emissions(CO, NOx, HC, PM) compare with conventional diesel fuel.

• 수산해양기술연구
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• 제53권1호
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• pp.89-97
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• 2017

Butanol has an ability to improve the ignition quality due to its lower latent heat of vaporization; it has an advantage to reduce a volume of a fuel tank because its energy density is higher than that of ethanol. Also, butanol-diesel oil blending quality is good because butanol has an effect to prevent the phase-separation between two fuels. Even if the blended oil contains water, it can reduce the corrosion of the fuel line. Thus, it is possible to use butanol-diesel oil blended fuel in diesel engine without modification, and it may reduce the environment pollution due to NOx and particulate and the consumption of diesel oil. Therefore, some studies are being advanced whether butanol is adequate as an alternative fuel for diesel engines, and the results of the combustion and exhaust gas emission characteristics are being presented. Though the injection and spray characteristics of butanol are more important in diesel combustion, the has not yet dealt with the matter. In this study, the influence in which differences of physical properties between butanol and diesel oil may affect the injection and spray characteristics such as injection rate, penetration, spray cone angle, spray velocity and process of spray development were examined by using CRDI system, injection rate measuring device and spray visualization system. The results exhibited that the injection and macroscopic spray characteristics of two fuels were nearly the same.

• Journal of Advanced Marine Engineering and Technology
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• 제39권4호
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• pp.412-417
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• 2015

IMO MEPC에서는 해양환경 보호를 위해서 선박으로부터 배출되는 배기가스 규제를 날로 점점 강화하고 있다. 특히, 2016년부터 건조되어 국제항해를 하는 모든 신조 선박에 대한 질소산화물(NOx) 배출량은 Tier-III 규제를 만족하게 되어 있다. 본 연구에서는 선박용으로 개발된 NOx 저감용 SCR(선택적 환원 촉매) 시스템을 기존 선박의 디젤발전기에 설치하여 NOx 저감성능을 파악하고자 하였다. 본 연구를 위하여 목포해양대학교 실습선 새누리호 디젤발전기의 배기 파이프라인을 개조 공사하여 요소 SCR 시스템을 설치하였으며, 요소 용액(40%) 분사 방법은 수동 모드와 PLC를 통한 자동 모드로 나누어 두 가지 방법으로 실험을 하였다. 수동 모드 방법을 통하여 암모니아 슬립 발생구간을 찾을 수 있었으며, 엔진부하별(25, 35 및 50%)로 최적의 요소 분사량을 조절할 수 있었다. 부하를 Down-Up(25%에서 50%로 올리면서) 시보다도 Up-Down(50%에서 25%로 내리면서) 시에 NOx 저감성능이 더 좋음을 알 수 있었으며, 본 바나듐계 촉매가 사용된 SCR 시스템을 기존 선박의 디젤발전기에 설치하여 질소산화물이 80% 이상 절감됨을 확인할 수 있었다.

• Safety and Health at Work
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• 제7권4호
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• pp.372-380
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• 2016

Background: The aim of this study was to estimate the number of workers exposed to diesel engine exhaust (DEE) by industry and year in the Republic of Korea. Method: The estimates of workers potentially exposed to DEE in the Republic of Korea were calculated by industry on the basis of the carcinogen exposure (CAREX) surveillance system. The data on the labor force employed in DEE exposure industries were obtained from the Census on Establishments conducted by the Korea National Statistical Office from 1993 to 2013. The mean values of prevalence rates adopted by EU15 countries were used as the primary exposure prevalence rates. We also investigated the exposure prevalence rates and exposure characteristics of DEE in 359 workplaces representing 11 industries. Results: The total number of workers exposed to DEE were estimated as 270,014 in 1993 and 417,034 in 2013 (2.2% of the total labor force). As of 2013, the industry categorized as "Land transport" showed the highest number of workers exposed to DEE with 174,359, followed by "Personal and household services" with 70,298, "Construction" with 45,555, "Wholesale and retail trade and restaurants and hotels" with 44,005, and "Sanitation and similar services" with 12,584. These five industries, with more than 10,000 workers exposed to DEE, accounted for 83% of the total DEE-exposed workers. Comparing primary prevalence rates used for preliminary estimation among 49 industries, "Metal ore mining" had the highest rate at 52.6%, followed by "Other mining" with 50.0%, and "Land transport" with 23.6%. Conclusion: The DEE prevalence rates we surveyed (1.3-19.8%) were higher than the primary prevalence rates. The most common emission sources of DEE were diesel engine vehicles such as forklifts, trucks, and vans. Our estimated numbers of workers exposed to DEE can be used to identify industries with workers requiring protection from potential exposure to DEE in the Republic of Korea.