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서충길(C. K. Seo),김화남(H. N. kim),최병철(B. C. Choi),정종우(J. W. Jeong) 한국동력기계공학회 2009 한국동력기계공학회 학술대회 논문집 Vol.2009 No.6
Selective catalytic reduction using urea is a powerful technique to reduce nitrogen oxides(NOx) emitted from diesel engines. However, it has a problems where NOx conversion efficiency is low at low temperature region with non-precious metal catalyst as zeolite. The purpose of this study is to understand fundamental characteristics of LNT(Lean NOx Trap) and SCR(Selective Catalytic Reduction) catalysts to improve NOx conversion efficiency and wide window width using LNT+SCR combination system. It was found that LNT Catalyst had much NOx storage capacity at 350°C condition than that at 200°C. NOx conversion efficiency of SCR catalyst was decremented about 5% with H<sub>2</sub>O 5% condition below temperature of 450°C. Hydrogen as a reductant which was used at LNT contributed NOx reduction, and this process formed NH<sub>3</sub> that is useful reductant for the SCR system. LNT+SCR combination system without additional injection was improved NOx reduction about 10-30% at temperature region below 400°C.
[디젤엔진] Bulk Combustion을 위한 메탄올의 자착화 특성에 관한 연구
김화남(H.N. Kim),김영길(Y.K. Kim),최병철(B.C. Choi),임명택(M.T. Lim) 한국자동차공학회 1999 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
New engine technologies are sought for resolution of the air pollution and energy issues over automobiles in the 21st century.<br/> Concept of bulk combustion has a great potential in this respect. Autoignition characteristics of methanol are numerically analyzed in continuation of the previous study on those of methane. Methanol is found to have better characteristics for spontaneous ignition after compression.
상용 CPF를 장착한 CRDI 디젤엔진에서 바이오 혼합연료 사용에 따른 배출가스 특성 및 입자수 분포 특성
김화남(H. N. kim),성용하(Y. H. Sung),김태준(T. J. Kim),최병철(B. C. Choi),임명택(M. T. Lim) 한국동력기계공학회 2007 한국동력기계공학회 학술대회 논문집 Vol.- No.-
We measured emission characteristics of CRDI diesel engine equipped with a commercial CPF. Experimental parameters adopted a neat diesel fuel, a blend of diesel fuel with 20% biodiesel, a blend of diesel fuel with 15% biodiesel and 5% ethanol. The experiments were carried out to measure the emission and engine performance according to ESC 13-mode cycles. The maximum torque with biodiesel blend fuel is slightly lower than that of neat diesel fuel in the entire the 13-mode cycles, and 5% ethanol and 15% biodiesel blend fuel is slightly higher than that of neat diesel fuel. HC and CO emissions of the biofuel blended diesel fuel were slightly increased, and mean conversion efficiencies of HC and CO on the commercial CPF were achieved about 70-87% in the ESC 13-mode. From the measurement by the Scanning Mobility Particle Sizer(SMPS), the total number and mass of nano-sized particles by a commercial CPF were decreased about 97.8% and 96.8 % in the range of the nano-size from 10.6 to 385nm, respectively.
[디젤엔진부문] Bulk Combustion을 위한 DME 연료의 자착화 특성 수치해석
임효준(H.J. Lim),김화남(H.N. Kim),김영길(Y.K. Kim),최병철(B.C. Choi) 한국자동차공학회 2000 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Nowadays, the most promising engine which has the best thermal efficiency as diesel engine and the best emission performance as gasoline engine is desired to be introduced into the future automotive society. Bulk combustion engine can be hoped to be one candidate engine of them<br/> In this paper, we tried to clarify autoignition characteristics by means of numerical analysis on DME fuel.<br/> As a result, we have found that OH radical is the most effective one for autoignition of DME and the operation with DME is possible in lower temperature condition than that with methanol.<br/>
디젤자동차용 SCR 촉매의 저온영역에서 NOx 정화율 개선
서충길(C.-K. Seo),김화남(H. N. Kim),최병철(B. C. Choi),이천환(C. H. Lee),오광철(G. C. Oh),이춘범(C. B. Lee) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
The purpose of this paper is to perform the optimum contents of ZrO₂ with a promoter to improve NOx reduction activity of a Cu-ZSM-5 catalyst in low temperature below 300℃. NOx conversion of ZrO₂(2wt%) improved to 10∼20% in the temperature range from 200℃ to 300℃ compared to no ZrO₂ loaded SCR catalyst. It is because the NH₃ absorption was improved by acidity strengthening of acid sites of SCR catalyst as well as the improvement of thermal stability by a resonable ZrO₂ loading. The LOT(light-off temperature) 50 of Cu-ZSM-5/ZrO₂(2wt%) appeared at 180℃ that was decreased about 50℃ compared with Fe-Zeolite catalyst. The maximum NOx conversion of Cu-ZSM-5/ZrO₂(2wt%) was obtained 93% at 300℃, however that of Fe-zeolite catalyst was 88% at 350℃.