• 한국대기환경학회지
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• 제5권1호
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• pp.79-87
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• 1989

In order to reduce the smoke emission from the in-service city bus, this study was evaluated the particulate reduction efficiency and regeneration ability of the catalitic trap oxidizer (CTO) on the city bus (D0846HM engine) equipped with it. Before the on-road CTO test, the laboratory test of CTO on engine test-bench was performed. Reduction efficiencies of smokes and particulates were 54 and 45%, and those of gaseous pollutants such as carbon monoxide (CO) and hydrocarbons (HC) were 90 and 60%. In order to evaluate the regeneration ability of the CTO by the catalytic oxidation of trapped particulate, field test was performed on the in-service road. The regeneration temperature was 350$^\circ$ which was same with the exhaust temperature of city bus.

• 한국화재소방학회논문지
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• 제34권2호
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• pp.22-29
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• 2020

본 연구에서는 개발 중인 현장지휘관 훈련 콘텐츠에 적용될 화재상황의 현실성 및 전문성 확보를 위하여 선행연구에서 선정한 7개 화재유형별 중 주거목적시설의 대표 가연물 화재실험을 통해 화재양상 및 열방출량, 연기발생량을 분석하였다. 측정결과 최대 열방출량은 소파가 728.6 kW로 가장 높게 측정되었으며, 다음으로는 매트리스+전기장판, 책상+의자, TV, 매트리스 순으로 나타났다. 총열방출량의 경우 소파가 226.2 MJ, 총 연기발생량은 경우 매트리스+전기장판이 2,259.5 ㎡로 가장 많이 발생하였다. 본 연구에서는 가연물의 화재양상 및 특성에 주안점을 두고 시험수행을 하였다는 한계점이 있으며, 추후 다양한 데이터 확보와 FDS를 활용한 시뮬레이션 평가가 이루어져야 할 것으로 판단된다.

• 에너지공학
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• 제13권1호
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• pp.20-27
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• 2004

본 연구에서는 고점도 저질유를 연료로 사용하는 디젤기관에 있어서 연료에 저비점 함산소물질을 혼합하였을 때의 배기배출물 특성변화에 대해 조사하였다. 실험은 6종류의 혼합물을 여러 혼합비로 베이스 연료에 첨가하여 기관 성능과 배기배출물 특성 변화에 대해 실시하였으며, 다음과 같은 결론을 얻었다. 저질유로의 저비점물질 흔합에 의해 매연 CO, PM, SOF 및 열소비율이 대폭적으로 개선되었다. 이러한 경향은 분사시기 지연시에 현저하였으며, 혼합물질의 비점이 낮을 수록 혼합비율이 클수록 또한 비함산소 물질보다는 함산소물질에 있어서 더 현저하였다. 또한, 저질유에 함산소물질 DMM을 20 vo1.% 흔합하고 연료분사시기를 지연시킬 경우에는 통상의 경유 운전을 상회하는 NOx-매연 트레이드 오프 관계가 얻어졌다. 따라서, 고점도의 저질유연료를 사용하는 디젤운전에 있어서도 저비점 함산소물질의 혼합에 의해 효과적이고 청정하게 사용될 수 있을 것으로 기대된다.

• 한국분무공학회지
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• 제21권2호
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• pp.95-103
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• 2016

The effect of pilot injection quantity on the combustion and emissions characteristics of a compression ignition engine with a biodiesel-compressed natural gas (CNG) dual fuel combustion (DFC) system is studied in this work. Biodiesel is used as a pilot injection fuel to ignite the main fuel, CNG of DFC. The pilot injection quantity is controlled to investigate the characteristics of combustion and exhaust emissions in a single cylinder diesel engine. The injection pressure and injection timing of pilot fuel are maintained at approximately 120 MPa and BTDC 17 crank angle, respectively. Results show that the indicated mean effective pressure (IMEP) of biodiesel-CNG DFC mode is similar to that of diesel-CNG DFC mode at all load conditions. Combustion stability of biodiesel-CNG DFC mode decreased with increase of engine load, but no notable trend of cycle-to-cycle variations with increase of pilot injection quantity is discovered. The combustion of biodiesel-CNG begins at a retarded crank angle compared to that of diesel-CNG at low load, but it is advanced at high loads. Smoke and NOx of biodiesel-CNG are simultaneously increased with the increase of pilot fuel quantity. Compared to the diesel-CNG DFC, however, smoke and NOx emissions are slightly reduced over all operating conditions. Biodiesel-CNG DFC yields higher $CO_2$ emissions compared to diesel-CNG DFC over all engine conditions. CO and HC emissions for biodiesel-CNG DFC is decreased with the increase of pilot injection quantity.

• 한국분무공학회지
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• 제29권2호
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• pp.53-59
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• 2024

Cars are one of the main causes of air pollution in large cities, and 34.6% of domestic air pollution emissions come from mobile sources, of which cars account for 69.6%. In particular, the importance of nitrogen oxides (NOx) and particulate matter (PM), which are major pollutants in diesel vehicles, is increasing due to their high contribution to emissions. Therefore, in this study, the problem of natural regeneration caused by low exhaust gas temperature during low speed and low load operation was solved by applying a complex regeneration DPF that is not affected by temperature conditions to large diesel vehicles with higher driving time and engine displacement than small and medium-sized vehicles. And the feasibility of application to large diesel vehicles was reviewed by measuring the emission reduction efficiency. As a result of the reduction efficiency test on the actual vehicle durability product, PM showed a reduction efficiency of 84% to 86%, and the reduction efficiency of gaseous substances showed a high reduction efficiency of over 90%. The actual vehicle applicability test was completed with three driving patterns: village bus vehicle, police car, and road-going construction equipment vehicle, and no device problems occurred until the end of the test. Both load and no-load smoke measurement results showed a smoke reduction efficiency of over 96%.

• 한국대기환경학회지
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• 제33권5호
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• pp.497-514
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• 2017

This study quantitatively analyzes the effects of emission inventory choices on the simulated particulate matter (PM) concentrations and the domestic/foreign contributions in the Seoul Metropolitan Area (SMA) with an air quality forecasting system. The forecasting system is composed of Weather Research and Forecasting (WRF)-Sparse Matrix Operator Kernel Emissions (SMOKE)-Community Multi-Scale Air Quality (CMAQ). Different domestic and foreign emission inventories were selectively adopted to set up four sets of emissions inputs for air quality simulations in this study. All modeling cases showed that model performance statistics satisfied the criteria levels (correlation coefficient >0.7, fractional error <50%) suggested by previous studies. Notwithstanding the apparently good model performance of total PM concentrations by all emission cases, annual average concentrations of simulated total PM concentrations varied up to $20{\mu}g/m^3$ (160%) depending on the combination of emission inventories. In detail, the difference in simulated annual average concentrations of the primary PM coarse (PMC) was up to $25.2{\mu}g/m^3$ (6.5 times) compared with other cases. Furthermore, model performance analyses on PM species showed that the difference in the simulated primary PMC led to gross model overestimation in general, which indicates that the primary PMC emissions need to be improved. The contribution analysis using model direct outputs indicated that the domestic contributions to the annual average PM concentrations in the SMA vary from 44% to 67%. To account for the uncertainty of the simulated concentration, the contribution correction factor method proposed by Bae et al. (2017) was applied, which resulted in converged contributions(from 48% to 57%). We believe this study shows that it is necessary to improve the simulated concentrations of PM components in order to enhance the accuracy of the forecasting model. It is deemed that these improvements will provide more accurate contribution results.

• 한국수소및신에너지학회논문집
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• 제23권5호
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• pp.530-537
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• 2012

This work experimentally investigates that Diesel-DME blended fuel influences combustion characteristics and emissions (NOx, CO, HC, smoke) in a single-cylinder DI diesel engine. Diesel is used as a main fuel and DME is blended for the use of its quick evaporating characteristics. Diesel and DME are blended by the method of weight ratio. Weight ratios for Diesel and DME are 95:5 and 90:10 respectively and the both ratios have been used altogether in blended fuel. The experiments are conducted in this study single cylinder engine is equipped with common rail and injection pressure is 700 bar at 1200 rpm. The amount of injected fuels is adjusted to obtain the fixed input calorie value as 972.2 J/cycle in order to compare with the fuel conditions. DME is compressed to 15 bar by using nitrogen gas thus it can be maintained the liquid phase. In this study, different system compared others paper is common rail system, also there is combustion and emission about compared DME and diesel fuel. It is expected to be utilized about blended fuel.

• 한국대기환경학회지
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• 제25권2호
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• pp.167-174
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• 2009

The AIRWARE System was developed from one of the EUREKA PROJECT E!3266-EUROENVIRON WEBAIR System. The AIRWARE can nowcast and forecast the air quality of Seoul and Gyeonggi-do regions. To nowcast and forecast concentration of pollutants, MM5, AERMOD/CAMx, and SMOKE Models were used for each meteorologic data, measured data, and emission data. All DB were constructed for 2001 year. The episode analysis and time series analysis were accomplished to analyze the AIRWARE reliability. The simulated results were very well agreed with measured result for measured pollutants and meteorological data. The developed AIRWARE system can analyze with real-time, support web-based air quality information. This information can used with policy data to manage the air quality and prepare reduction plan in air impact assessment or air environmental plan.

• 자동차안전학회지
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• 제10권3호
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• pp.27-31
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• 2018

The People have a bad perception about diesel vehicle because of serious air pollution, increase fine dust and global vehicle company's diesel gate. Starting the project in 2005, Ministry of Environment has been supporting that is exhaust gas reduction devices (DPF) on diesel vehicles in the metropolitan area. During the period of 2017.01.01 to 2017.12.31, 10,030 diesel vehicles installed exhaust gas reduction devices (DPF). Among them, 9,921 diesel vehicles that they have sufficient data for analysis were analyzed amount of particulate matter reduction before and after exhaust gas reduction devices (DPF) was installed. Opacity smoke meter measures the concentration of particulate matter. So concentration of particulate matter was converted into a mass unit, and then calculated the total amount of reduced particulate matter. It was estimated that social benefits is costs required to remove it from the total amount of particulate matter.

• 한국자동차공학회논문집
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• 제14권6호
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• pp.73-81
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• 2006

A commercial diesel engine was converted into a dedicated natural gas engine to reduce the exhaust emissions in a retrofit of a diesel-fueled vehicle. The cylinder head and piston were remodeled into engine parts suited for a spark ignition engine using natural gas. The remodeling of the combustion chamber changed the compression ratio from 21.5 to 10.5. A multi-point port injection(MPI) system for a dedicated natural gas engine was also adopted to increase the engine power and torque through improved volumetric efficiency, to allow a rapid engine response to changes in throttle position, and to control the precise equivalence ratio during cold-start and engine warm-up. The performance and exhaust emissions of the retrofitted natural gas engine after remodeling a diesel engine are investigated. The emissions of the retrofitted natural gas engine were low enough to satisfy the limits for a transitional low emission vehicle(TLEV) in Korea. We concluded that a diesel engine can be effectively converted into a dedicated natural gas engine without any deterioration in engine performance or exhaust emissions.