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ETC 적용 승용 디젤 엔진에서 흡기 공기 및 저압 배기가스 재순환 유량에 따른 NO<SUB>x</SUB>, PM, 연비 특성에 관한 연구
박준혁(Junhyuk Park),임기훈(Gihun Lim),윤준규(Junkyu Yoon),최영(Young Choi),강건용(Kernyong Kang),이석환(Seokhwan Lee) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Previous experimental studies on diesel engine have demonstrated the potential of Low Pressure EGR(LP EGR) system. Actually, contrary to High Pressure EGR(HP EGR) system, the gas flow through the turbine is unchanged while varying the EGR rate. Thus, high boost pressure can be reached, allowing the use of high rates of supplemental EGR. The LP EGR system seems to helpful method to further reduce NO x emissions while maintaining PM emissions at a low level. The research activity in this paper is aimed to carry out an analysis of the potentiality of the LP EGR system equipped with Electronic Throttle Control(ETC) system. Using LP EGR system with ETC, an EGR gas amount is controled by throttling an intake air. This experiment are conducted on a 2.0L HSDI common-rail DI engine equipped with HP and LP EGR systems on test bench under medium load condition. The characteristics of combustion and exhaust gas, especially BSFC, BSNO x and NO x -PM trade-off, are studied while varying the EGR rate, as compared with HP EGR system and LP EGR system with back pressure valve. The overall results identified benefits on both the fuel consumption and emissions with the use of a LP EGR system equipped with ETC. balanced performance on BSFC and NOx reduction although HP EGR has the best performance of NOx reduction.
저압 EGR을 적용한 디젤엔진의 희석비에 따른 연소 특성 비교
임기훈(Gihun Lim),박준혁(Junhyuk Park),최영(Young Choi),이선엽(Sunyoup Lee),김영민(Yongmin Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
Exhaust Gas Recirculation(EGR) is the most effective technology for the reduction of NO<SUB>x</SUB> emission compared with Selective Catalytic Reduction(SCR) or Lean NO<SUB>x</SUB> Trap(LNT) in diesel engine. A large amount of EGR gas is indispensable to meet the stringent regulation of NO<SUB>x</SUB> emission. As Low Pressure(LP) EGR is almost independent of the control of Variable Geometry Turbocharger(VGT) at specific boost pressure, LP EGR has more advantages than conventional High Pressure(HP) EGR in terms of EGR supply. In this study, the influence of LP EGR on the combustion characteristics has been compared with that of HP EGR at constant boost pressure in direct injection diesel engine. Dilution ratio was employed as independent parameter to analyze the effect of dilution for each EGR loop. Fuel consumption and PM emissions in LP EGR experiment were slightly lower than those of HP EGR with the same level of <SUB>x</SUB> emission.
저압 EGR을 적용한 디젤엔진의 희석비에 따른 연소 특성 비교
임기훈(Gihun Lim),박준혁(Junhyuk Park),최영(Young Choi),이선엽(Sunyoup Lee),김영민(Yongmin Kim) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.5
디젤엔진에서 배기가스 재순환(EGR; Exhaust Gas Recirculation)은 선택적 환원 촉매나 NOx 흡장 촉매에 비해 NOx 배출 저감을 위한 가장 효과적인 기술이다. 점점 더 강화되어 가는 NOx 배출 규제를 만족시키기 위해서는 많은 양의 EGR 가스 공급이 필요하다. 저압 EGR은 일정한 과급 압력에서 가변형상 터보차져의 제어와 거의 독립적이기 때문에 EGR 공급 측면에서 보면 저압 EGR이 기존의 고압 EGR에 비해서 더 많은 장점을 갖는다. 본 연구에서는 저압 EGR이 연소 특성에 미치는 영향을 고압 EGR을 적용했을 때와 비교하였다. 각 EGR 루프에 대해 혼합기의 희석 정도에 따른 영향을 분석하기 위해 독립변수로써 희석비를 사용하였다. 저압 EGR을 적용하였을 때, 고압 EGR을 적용했을 때와 동등한 NOx 배출량을 유지하면서 연료 소비율과 매연 배출은 고압 EGR의 경우보다 좀 더 낮은 결과를 보였다. Exhaust gas recirculation (EGR) is more effective than selective catalytic reduction (SCR) or lean NOx trap (LNT) for the reduction of NOx emissions in diesel engines. A large amount of EGR gas is necessary to satisfy the stringent regulations on NOx emissions. Low pressure loop (LPL) EGR is almost independent of the variable geometry turbocharger (VGT) at a specific boost pressure, so LPL EGR is better than conventional high pressure loop (HPL) EGR in terms of EGR supply. We compare the influence of HPL EGR and LPL EGR on the combustion characteristics at a constant boost pressure in a diesel engine. The dilution ratio was employed as an independent parameter to analyze the effect of the dilution of the intake charge for each EGR loop. At the same level of NOx emissions, the fuel consumption and smoke opacity were slightly lower for LPL EGR than for HPL EGR.
저압 EGR을 적용한 디젤엔진에서 과급 압력에 따른 연소 및 배기 특성
임기훈(Gihun Lim),박준혁(Junhyuk Park),최영(Young Choi),이석환(Seokhwan Lee),강건용(Kernyong Kang) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
The purpose of this study is to reduce nitrogen oxide(NOx) emission in diesel engine with minimum increase of particulate matter(PM) emission and fuel consumption. Air excess ratio is one of factors that limit Exhaust Gas Recirculation(EGR) rate due to increase of PM emission. Air-fuel mixture can be leaner by increasing a boost pressure through Variable Geometry Turbocharger(VGT). The boost pressure in diesel engine applied conventional High Pressure(HP) EGR is related with EGR gas supply because the output of VGT is decreased as EGR rate increases. On the other hand, the boost pressure in diesel engine equipped with Low Pressure(LP) EGR is almost independent of EGR gas supply because EGR gas is extracted in downstream of VGT. For those reasons, LP EGR can be a method that reduces NOx emission with regardless increase of PM emission and fuel consumption. In this study, combustion and emission characteristics in LP EGR system were compared with those in HP EGR system depending on the boost pressure. 111.3 ㎪ of the boost pressure was optimized in HP EGR system. In case of LP EGR system, however, 121.3 ㎪ of the boost pressure, of which air-fuel mixture is more learner than 111.3 ㎪ of the boost pressure, can be reached with the same amount of NOx emission of HP EGR system. PM emission in LP EGR system was expected to be lower than that in HP EGR system while maintaining reduction of NOx emission.
CRISPR-Cap: multiplexed double-stranded DNA enrichment based on the CRISPR system
Lee, Jeewon,Lim, Hyeonseob,Jang, Hoon,Hwang, Byungjin,Lee, Joon Ho,Cho, Junhyuk,Lee, Ji Hyun,Bang, Duhee Oxford University Press 2019 Nucleic acids research Vol.47 No.d1
<P><B>Abstract</B></P><P>Existing methods to enrich target regions of genomic DNA based on PCR, hybridization capture, or molecular inversion probes have various drawbacks, including long experiment times and low throughput and/or enrichment quality. We developed CRISPR-Cap, a simple and scalable CRISPR-based method to enrich target regions of dsDNA, requiring only two short experimental procedures that can be completed within two hours. We used CRISPR-Cap to enrich 10 target genes 355.7-fold on average from <I>Escherichia coli</I> genomic DNA with a maximum on-target ratio of 81% and high enrichment uniformity. We also used CRISPR-Cap to measure gene copy numbers and detect rare alleles with frequencies as low as 1%. Finally, we enriched coding sequence regions of 20 genes from the human genome. We envision that CRISPR-Cap can be used as an alternative to other widely used target-enrichment methods, which will broaden the scope of CRISPR applications to the field of target enrichment field.</P>
Solubility of triclocarban in pure alkanols at different temperatures
김화용,신문삼,Junhyuk Lim,Sunghyun Jang,Hye Kyoung Cho 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.1
Triclocarban solubility in six pure alcohols was determined in the temperature interval from 278.15 to 318.15K. The experimental solubility data were correlated by the Wilson, the nonrandom two liquid (NRTL) and the universal quasi-chemical (UNIQUAC) models. The data are well fitted with all three models for the six pure alcohols studied here. Also, ab initio geometry optimization of triclocarban was performed using the density functional theory (DFT)based on DMol3 method.
권영두(Youngdoo Kwon),이준혁(Junhyuk Lee),손창현(Changhyun Sohn),최종하(Jongha Choi),임재규(Jaegyoo Lim),이헌우(Hunwoo Lee) 한국자동차공학회 2004 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Link-system is necessary to transfer power and has widely been used in many fields such as an automobile, robot, mechanical engineering. This dissertation indicates that we design double three-bar and double four-bar driver by motor so that they can have each other difference degree. Therefore, we analyze link mechanism to have the same output for each bar coping with the same input for it. Unless it is accomplishes, we will look for the length and position of the link minimizing weight. We used SZGA(Successive zooming genetic algorithm; Computers & Structure, 2003), the technique of optimum design, the optimum value obtained by it is verified by an experiment, fortran link program developed in person and Recurdyn which is 3-D Dynamic Mechanics Analysis package.