본 연구에서는 소형선박용 중·고속 디젤엔진에 적용하여 연구 중인 SCR+DPF 기술을 저속엔진이 설치된 선박에 탑재하여 해상 실증 시험을 수행하였다. 대상 선박(총 톤수 2,881 톤, 정격출력 1,470kW@240rpm ×1)은 국내 연해를 운항하는 일반화물선으로 배출저감설 비의 선박 탑재를 위해 도면 개발, 승인 및 선박 임시검사를 수행하였다. 저감성능 확인을 위해서 가스상물질 측정장비는 NOx technical code 및 ISO-8178의 분석방법을 준용하는 장비를 사용하였으며, 입자상물질 측정장비는 국제해사기구(IMO)에서 논의하고 있는 블랙카본 측정 방법 중 하나인 스모크미터를 사용하였다. 시험은 황 함유량 따라 MGO(0.043%), LSFO(0.42%) 2종의 연료를 사용하였으며 실제 운항 하는 엔진회전수(130, 160 및 180 rpm)를 고려하여 시험 조건을 설정하였다. 시험 조건에 따라 배출저감설비의 전·후단에서 가스상 및 입 자상(매연) 물질을 측정하여 배출저감설비의 저감효율을 확인하였으며 모든 시험 조건에서 NOx의 경우 90% 이상, 입자상물질(매연)의 경우 95% 이상의 저감효율을 확인하였고 엔진 성능의 영향을 줄 수 있는 배기가스 압력은 허용배압 기준인 50mbar 이하를 만족하였다. 본 연구를 통해 해상실증 연구의 중요성과 중소형 저속엔진 선박의 질소산화물 및 입자상물질의 동시 저감을 위한 대응 기술로 SCR+DPF 설비 적용 가능성을 확인할 수 있었다.

To understand the effect of high pressure on nitrogen oxides (NOx) formation in water added methane flames, opposed nonpremixed Water-methane/air (H2O-CH4/air) flames are numerically studied with high initial pressure. With GRI 3.0 detailed kinetic mechanism, NOx emissions are predicted for various strain rates. Due to high pressure, the chemical species are distributed in a narrow region, which means the thickness of the flame is thin. This can be clearly seen with high strain rate. Elevated pressure increases maximum temperature of flames which results in increased NOx emission. Even with elevated initial pressure, NOx emissions for H2O added methane flames are significantly decreased compare to pure methane flame. In addition, increased strain rate is also significant factor for decreasing NOx emission. With detailed rate of production analysis, in case of high pressure, it is confirmed that NO2 pathway is the most dominant reaction pathway than any other pathways.

본 연구는 이상적인 실험환경이 아닌 실제 일반국도(국도 3호선)를 분석 대상으로 실시간으로 수집된 교통자료와 NOx 대기 오염 측정 자료를 이용하여 이들 사이의 관계를 규명하고 그 특성을 분석하고자 한다. 또한 이러한 관계를 이용하여 현장에서 실제 적용이 가능하며 대기오염도를 모니터링을 할 수 있는 일반국도의 차량배출가스로 인한 NOx 대기오염도 추정 모형을 개발하고자 한다. 모형의 구축에 있어서 측정 장비 및 기타 변동요인으로 인한 특이점을 제거하기 위하여 로버스트 분석을 이용하였고 바람의 영향을 고려하지 않은 경우와 바람의 영향을 고려한 경우에 대해서 모형을 구축하였다. 본 연구의 결과는 교통정책 시행에 따른 차량배출가스로 인한 대기오염 현황을 파악하고 교통정책의 환경적 효과를 평가하는데 활용될 수 있을 것이다.

The Effects of cooled and hot EGR(exhaust gas recirculation) on the characteristics of smoke and NOx emission have been investigated using a single cylinder, water-cooled, four cycle, DI diesel engine at several loads and speeds. In this study, a manually controlled EGR system was installed on a agricultural diesel engine which was operated at various operating system. And, the effects of hot EGR and cooled EGR on smoke and NOx emission were compared. The results showed that cooled EGR method was more effective than hot EGR method on smoke and NOx emission.

The accuracy of ozone sensitivity coefficients estimated with HDDM (High-order Decoupled Direct Method) can vary depending on the NOx (Nitrogen Oxides) and VOC (Volatile Organic Compound) conditions. In order to evaluate the applicability of HDDM over the Seoul Metropolitan Area (SMA) during a high ozone episode in 2007 June, we compare BFM (Brute Force Method) and HDDM in terms of the 1st-order ozone sensitivity coefficient to explain ozone change in response to changes in NOx and VOC emissions, and the 2nd-order ozone sensitivity coefficient to represent nonlinear response of ozone to the emission changes. BFM and HDDM estimate comparable ozone sensitivity coefficients, exhibiting similar spatial and temporal variations over the SMAduring the episode. NME (Normalized Mean Error) between BFM and HDDM for the episode average 1st- and 2nd-order ozone sensitivity coefficients to NOx and VOC emissions are less than 3% and 9%, respectively. For the daily comparison, NME for the 1st- and 2nd-order ozone sensitivity coefficients are less than 4% (R2> 0.96) and 15% (R2> 0.90), respectively. Under the emission conditions used in this study, two methods show negative episode average 1st-order ozone sensitivity coefficient to NOx emissions over the core SMA. The 2nd-order ozone sensitivity coefficient to NOx emissions leads ozone to respond muchnonlinear to the reduction in NOx emissions over Seoul. Nonlinear ozone response to reduction in VOC emissions is mitigated due to the 2nd-order ozone sensitivity coefficientwhich is much smaller than the 1st-order ozone sensitivity coefficient to the emissions in the magnitude.

The Kyoto Protocol, that had been in force from February 16, 2005, requires significant reduction in CO₂emissions for all anthropogenic sources containing transportation, industrial, commercial, and residential fields, etc, and automotive emission standards for air pollutants such as particulate matter (PM) and nitrogen oxides (NOx) become more and more tight for improving ambient air quality. This paper has briefly reviewed homogeneous charge compression ignition (HCCI) combustion technology offering dramatic reduction in CO₂, NOx and PM emissions, compared to conventional gasoline and diesel engine vehicles, in an effort of automotive industries and their related academic activities to comply with future fuel economy legislation, e.g., CO₂emission standards and corporate average fuel economy (CAFE) in the respective European Union (EU) and United States of America (USA), and to meet very stringent future automotive emission standards, e.g., Tier 2 program in USA and EURO V in EU. In addition, major challenges to the widespread use of HCCI engines in road applications are discussed in aspects of new catalytic emissions controls to remove high CO and unburned hydrocarbons from such engine-equipped vehicles.