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Urea-SCR 시스템에서 De-NO<SUB>x</SUB> 성능 향상을 위한 배기관 설계 최적화에 관한 실험적 연구
이재균(Jae-Kyoun Lee),윤여빈(Yu-Bin Yoon),송춘섭(Chun-Sub Song),박영준(Young-Joon Park),조용석(Yong-Seok Cho),주재근(Jae-Geon Joo),김현옥(Hyun-Ok Kim) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
The selective catalytic reduction(SCR) system is potentially a highly-effective means of NOx reduction for diesel engine. Generally, SCR makes use of a reductant added to the exhaust gas that can be used for reacting nitric acids to nitrogen. The reductant, ammonia(NH₃) generated from a liquid urea-water solution. The ideal ratio of NH₃ molecules to NOx molecules is 1:1 based on NH₃ consumption and having NH₃ available for reaction of all of the exhaust NOx. The SCR system has good NOx conversion performance in the temperature window about 250 to 400℃, low space velocity also leads to increase of NOx conversion efficiency, due to long residence time in the catalyst. In this paper, Urea-SCR system has tried to find the optimal shape of the exhaust pipe for improvement of de-NOx performance. This study used the blade-type mixer and various pipes for reduction at up stream of catalyst to improve the uniformity. As a result, the de-NOx performance of Urea-SCR system was improved and exhaust geometry was optimized, too.
선택적 환원 촉매(SCR)에서 배출가스 특성에 따른 NO<SUB>x</SUB> 변환효율 및 환원제(NH₃) 분사량 최적화에 관한 실험적 연구
오준석(June-Seok Oh),윤여빈(Yu-Bin Yoon),송춘섭(Chun-Sub Song),박영준(Young-Joon Park),이성욱(Seang-Wock Lee),조용석(Yong-Seok Cho) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
The selective catalytic reduction(SCR) system is potentially a highly-effective means of NOx reduction for diesel engine. Generally, SCR makes use of a reductant added to the exhaust gas that can be used for reacting NO and NO₂ to N₂. The reductant, ammonia(NH₃) generated from a liquid urea-water solution. De-NOx process in the SCR, the ideal ratio of NH₃ molecules to NOx molecules is 1:1 for high efficiency of NOx reduction. The SCR system has good NOx reduction performance in the temperature window of about 250 to 400℃, low space velocity also leads an increase of NOx reduction efficiency, due to long residence time in the catalyst. This paper reviews a laboratory study to evaluate the effects of NOx-NH₃ concentrations, gas temperature and space velocity on the NOx reduction efficiency of the SCR. The maximum reduction efficiency is indicated when the NH₃ to NOx ratio is 1.2 and the space velocity is 30,000 h?¹ in 300℃. However, under various exhaust conditions, NH₃ injection amount need to be controlled for a high NOx conversion efficiency because of reducing unnecessary NH₃ consumption. Based on results of the rig-test, this study suggests the control strategy of NH₃ injection for optimizing NOx reduction efficiency.
LNT 촉매에서 환원제 분사 조건에 따른 De-NO<SUB>x</SUB> 특성에 관한 실험적 연구
모지환(Ji-Hwan Mo),박영준(Young-Joon Park),송춘섭(Chun-Sub Song),윤여빈(Yu-Bin Yoon),이성욱(Seang-Wock Lee),조용석(Yong-Seok Cho) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
LNT(Lean NOx Trap) catalyst is an aftertreatment system typically used to reduce oxides of nitrogen(NOx) emissions for diesel engine. During the lean condition of exhaust gas, NOx is stored in the LNT catalyst and released and reduced during the rich condition of exhaust gas. In generally, rich condition of exhaust gas is made by post fuel injection or injection of the reductant such as CO₂, HC. The most effective method for de-NOx performance is an optimum injection rate of reductant as a function of exhaust gas condition. Injection rate of reductant made by diesel fuel has effected on the fuel economy and NOx reduction efficiency. This paper aimed to figure out evaluate to effect of exhaust gas temperature, O₂ concentration in exhaust gas and mass of reductant injection for de-NOx peformance of LNT catalyst using the test rig. Space velocity is held 30,000 h?¹ that is generally measured high reduction performance in catalyst. In result, NOx conversion efficiency is the highest when the specification temperature of exhaust gas and reduced NOx concentration in exhaust gas as injection rate of reductant increases. O₂ concentration in exhaust gas is 4%, NOx reduction efficiency is higher than 10% of O₂ concentration in exhaust.
합성가스를 이용한 SI엔진의 아이들 성능 개선에 관한 연구
김창기(Chang-Gi Kim),송춘섭(Chun-Sub Song),조용석(Young-Seok Cho),강건용(Kern-Young Kang) 한국연소학회 2006 한국연소학회지 Vol.11 No.4
In this study, syngas which is reformed from fossil fuel and has hydrogen as a major component, was added to a gasoline engine to improve combustion stability and exhaust emissions of idle state. Syngas fraction of the total supplied fuel varied to 0 %, 25 %, 50 % with various ignition timing and excess air ratio. Combustion stability, exhaust emissions, fuel consumption and exhaust gas temperature were measured to investigate the effects of syngas addition on idle performance. Results showed that syngas has ability to widely extend lean operation limit and ignition retard range with dramatical reduction of engine out emissions. It is supposed that the usage of syngas in the internal combustion engine is an effective solution to meet the future strict emission regulations.