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모사 배기관내 Urea 수용액 분무 균일도 측정에 관한 연구
문웅기(Woongki Mun),오정모(Jungmo Oh),한영덕(Youngdeok Han),이진하(Jinha Lee),이기형(Kihyung Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
Diesel engines have to meet with the severe emission regulations in terms of NOx and PM. A dramatic reduction in NOx and PM emissions could be achieved with after-treatment systems such as Lean NOx Trap (LNT) and Urea-SCR. However, the high temperatures (250 ~ 350 ℃) in the exhaust pipe affects spray behavior of the secondary injector which is used for supplying the Urea-SCR. This high temperature makes it difficult to achieve uniform distribution of the reducing agent in the manifold. If the injected agent is uniformly distributed, the emissions are dramatically decreased. This paper presents the characteristics of Urea-SCR injector for injecting in the exhaust pipe. The reducing agents were a 32.5% Urea solution. The purpose of this study was to investigate the spray characteristics of injector such as spray angle, injection quantity, penetration length and SMD. In addition, Uniformity Index(UI) is calculated from the acquired images by using image processing method to clarify the distribution of spray.
모사배기관내 Urea수용액의 분무 거동 특성에 관한 연구
문웅기(Woongki Mun),오정모(Jungmo Oh),한영덕(Youngdeok Han),이진하(Jinha Lee),이기형(Kihyung Lee) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
Recently, many technologies were developed to satisfy the severe emission regulations. Especially, a diesel engine was spotlighted as a CO₂ reduction technology because of its higher thermal efficiency and lower fuel consumption. However, the diesel engine inevitably produces the emission of NOx and PM. Moreover, it is not easy to satisfy the regulations on the emission of NOx and PM, which are getting more strengthened. One of the methods is to develop the new combustion concept using multistage injection such as HCCI and PCCI. The another method is to improve after-treatment systems such as lean NOx trap catalyst and Urea-SCR. Especially, Urea-SCR system have some advantages such as a high conversion efficiency and a wide operation conditions. Some companies already released a vehicle adapted this system. However, this technology still has many difficulties for applying to a diesel engine. In this study, a laser diagnostics and high speed camera are used to analyze injector spray characteristics and to present a distribution of reduction in transparent manifold.
가솔린 인젝터를 디젤엔진용 HC-LNT 촉매에 적용하기 위한 최적 분사 조건에 관한 연구
오정모(Jungmo Oh),문웅기(Woongki Mun),김기범(Kibum Kim),이진하(Jinha Lee),이기형(Kihyung Lee) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.2
희박 공연비에서 동작하는 디젤 엔진은 NOx 를 저감시키기 위해서 주기적으로 과농한 분위기를 형성해 주어야 한다. 최근 배기관 내에 환원제로서 경유를 직접 분사하는 HC-LNT 방식이 활발히 연구되고 있다. 이러한 연구는 NOx 저감을 위해 HC 의 농도를 제어하는 기술로서, 실제 배기관내에 HC 가 균일하게 분포하여야 촉매의 정화효율이 향상되므로 HC 를 균일하게 분사하는 방법의 최적화가 가장 중요하다. 본 연구에서는 저압에서 미립화 특성이 양호한 가솔린 흡기포트 분사용 인젝터를 이용하여, 가시화 방법으로 실제 배기관내에서의 환원제 분무 거동 특성을 측정하였고 NOx 정화 특성간의 관계를 실험적으로 비교함으로써, 인젝터의 최적 부착 조건과 분사 조건을 파악하였다. NOx (Nitrogen Oxide) reduction system periodically needs a rich or stoichiometric operating condition to reduce NOx. A new method that optimizes the control of external HC injection into a diesel exhaust pipe for HC-type LNT (Lean NOx Trap) catalyst system has been developed. In this paper, these catalysts are called HC-LNT catalysts. The concentration and amount of HC can be controlled by controlling the external injection. In this study, we investigated the relationship between the spray behavior of hydrocarbons injected into the transparent exhaust pipe and NOx reduction characteristics. From the results of this experiment, we obtained useful information about the optimum injection and position of HC injector to the exhaust pipe. Further, we obtained useful information about the optimal injection condition for an HC-LNT catalyst system with a gasoline PFI (port fuel injection) typeinjector.
MIXER 종류에 따른 LNT 환원제 분무 영향에 관한 연구
한영덕(Youngdeok Han),오정모(Jungmo Oh),문웅기(Woongki Mun),김기범(Kibum Kim),이진하(Jinha Lee),이기형(Kihyung Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.5
Automotive engines require strategies to fulfill the emission regulations in terms of NOx and PM. A dramatic reduction in NOx and PM emissions could be achieved with innovative combustion strategies such as HCCI and LTC. In spite of high cost of after-treatment systems, Lean NOx Trap (LNT) and Urea-SCR are considered more practical strategy to suppress the engine-out emissions substantially. Those after-treatment systems generally employ secondary injection, which make it difficult to achieve uniform distribution of the reducing agent in manifold. Therefore, an effect of a variety of mixer-types on spatial distribution of LNT reducing agent was investigated to promote a performance of LNT system. When the LNT reducing agent was directly injected against the mixers in a transparent manifold, the spray images were taken with a high speed camera, and the spatial distribution of the spray was analyzed using image processing technique