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.

HC-LNT 2차 분사의 배기관내 분무 거동과 NOx 저감 특성

오정모(Jungmo Oh),이기형(Kihyung Lee),이진하(Jinha Lee) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2007 No.11

Urea 수용액의 배기가스 유동장내 분무 특성과 분무 균일도에 관한 연구

오정모(Jungmo Oh),차원심(Wonsim Cha),김기범(Kibum Kim),이진하(Jinha Lee),이기형(Kihyung Lee) 한국자동차공학회 2011 한국 자동차공학회논문집 Vol.19 No.3

Diesel engines can produce higher fuel efficiency and lower CO₂ emission, they are subject to ever more stringent emission regulation. However, there are two major emission concerns for diesel engines like such as particulate matter (PM) and nitrogen oxides (NOx). Moreover, it is not easy to satisfy the regulations on the emission of NOx and PM, which are getting more strengthened. One of the solutions is to apply the new combustion concept using multistage injection such as HCCI and PCCI. The other solution is to apply after-treatment systems. For example, lean NOx trap catalyst, Urea-SCR and others have various advantages and disadvantages. Especially, Urea-SCR system have advantages such as a high conversion efficiency and a wide operation conditions. Hence the key factor to implementation of Urea-SCR technology, good mixing of urea(Ammonia) and gas, reducing Ammonia slip. Urea mixer components are required to facilitate evaporation and mixing because the liquid state of urea poses significant barriers for evaporation, and the distance to mixer is the most critical that affect mixer performance. In this study, to find out the distance from injector to mixer and simulation factor, a laser diagnostics and high speed camera are used to analyze urea injector spray characteristics and to present a distribution of urea solution in transparent manifold In addition, Droplet Uniformity Index is calculated from the acquired images by using image processing method to clarify the distribution of spray.

가솔린 인젝터를 디젤엔진용 HC-LNT 촉매에 적용하기 위한 최적 분사 조건에 관한 연구

오정모(Jungmo Oh),김기범(Kibum Kim),이진하(Jinha Lee),이기형(Kihyung Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5

희박 공연비애서 동작하는 디젤 엔진은 NOx를 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 HC의 농도를 제어하는 기술로서, 실제 배기관내에 HC가 균일하게 분포하여야 촉매의 정화효율이 향상되므로 HC를 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(s)) reduction system needs rich or stoichiometric operating condition periodically to reduce NOx. A new method that optimizes a control of external HC injection to diesel exhaust pipe for HC type LNT(Lean NOx Trap) catalyst system has been developed. These catalysts are called the HC-LNT catalyst in this paper. The concentration and amount of HC can be controlled with the control of external injection. This research investigated interrelationship between spray behavior of hydrocarbons injected into the transparent exhaust pipe and NOx reduction characteristics. From this experiment, we obtained useful information about the optimum injection and position of HC injector to the exhaust pipe. From this experiment, we obtained useful information about the optimal injection condition for HC-LNT catalyst system with a PFI(Port fuel injection) gasoline injector.

Urea 수용액 분사용 인젝터의 분무 특성과 배기관내 분무 거동 특성

오정모(Jungmo Oh),한영덕(Youngdeok Han),김기범(Kibum Kim),이기형(Kihyung Lee) 대한기계학회 2010 大韓機械學會論文集B Vol.34 No.11

디젤 엔진은 가솔린 엔진에 비해 열효율이 높고 이산화탄소 배출량이 적다. 그러나 입자상물질(PM)과 질소산화물(NOx)의 배출량이 가솔린 엔진보다 많은 단점을 가지고 있다. 디젤 엔진의 연소 배출물 중 질소 산화물을 저감시키기 위하여 LNT와 Urea-SCR과 같은 후처리 시스템이 최근 활발히 연구되고 있다. Urea-SCR은 Urea 수용액을 공급하기 위한 2차 분사 시스템이 필요하고, 분사된 Urea 수용액의 분무 거동 특성과 균일도에 따라서 촉매의 효율이 크게 달라진다. 본 연구에서는 배기관에 분사된 Urea 수용액의 분무균일도를 향상시키기 위하여 인젝터의 기초 분무 특성을 파악하였고, 모사배기관 시스템과 가시화 장비를 이용하여 배기관내에서의 분무 거동 특성을 파악하였다. Recently, many technologies have been developed in order to satisfy stringent emission regulations. However, in the case of diesel engines, the stringent emission regulations with respect to NOx and PM have not yet been satisfied. A dramatic reduction in the NOx and PM emissions could be achieved by using after-treatment systems such as lean NOx trap (LNT) and urea-SCR systems. However, the high temperature in the exhaust pipe affects the spray behavior of the secondary injector, which is used for supplying the Urea-SCR. Because of this high temperature, it is difficult to achieve uniform distribution of the reducing agent in the manifold. In this paper, the characteristics of a urea-SCR injector used for injecting in the exhaust pipe are presented. The purpose of this study was to investigate the spray characteristics of the injector, such as the spray angle, injection quantity, and SMD. In addition, laser diagnostics and high-speed-camera images were used to analyze the injector spray characteristics and to present a distribution of reduction in the transparent manifold.

Urea-SCR 시스템에서 열전대를 이용한 균일도 측정에 대한 연구

오정모(Jungmo Oh),박상기(Sangki Park),김형익(Hyungik Kim),인병덕(Byungdeok In),이기형(Kihyung Lee) 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5

2차 분사시스템을 갖는 De-NOx 시스템의 충돌판 형상에 따른 연료의 혼합 및 증발 특성 향상을 위한 연구

박상기,오정모,Park, Sangki,Oh, Jungmo 해양환경안전학회 2016 海洋環境安全學會誌 Vol.22 No.7

A secondary injection system in a diesel engine has benefits: it can be controlled independently without interrupting engine control, it can be adapted to various layouts for exhaust systems, and it pose no reductant dilution problems compared to post injection systems in the combustion chamber or other supplemental reductant injections. In a secondary injection system, the efficiency of the catalyst depends on the method of reducing the supply. The reductant needs to be maintained and optimized with constant pressure, the positions and angles of injector is a very important factor. The concentration and amount of reductant can be changed by adjusting secondary injection conditions. However, secondary injection is highly dependent upon the type of injector, injection pressure, atomization, spray technology, etc. Therefore, it is necessary to establish injection conditions the spray characteristics must be well-understood, such as spray penetration, sauter mean diameter, spray angle, injection quantity, etc. Uniform distribution of the reductant corresponding to the maximum NOx reduction in the DeNOx catalyst system must also assured. With this goal in mind, the spray characteristics and impingement plate types of a secondary injector were analyzed using visualization and digital image processing techniques. 디젤엔진에서는 2차 분사 시스템은 다양한 배기 시스템에 적용이 가능하고, 엔진 제어와 관계없이 독립적으로 제어가 가능하기 때문에 환원제 희석 면에서도 후분사 또는 다른 농후한 환원제 분위기 형성 방법 등에 비해 장점이 많다. 2차 분사 시스템에서는 환원제의 공급 방법에 따라서 촉매의 효율은 달라질 수밖에 없다. 환원제는 일정압력 이상으로 유지 및 최적화가 필요하고, 인젝터의 위치 및 각도의 선정은 매우 중요한 인자이다. 본 논문에서는 2차 분사 조건을 변화시켜 환원제의 농도와 양을 변화시켰다. De-NOx 촉매 시스템에서 최대의 NOx 정화 효율에 적합한 환원제 분사 조건들의 선정이 필요하고, 분무 도달거리, 분무 평균 입경, 분무각, 분사량 등의 분무 특성과 환원제의 균일 분포를 잘 파악하여야 한다. 이와 같은 목적을 위하여 2차 분사에서 충돌판 형상에 의한 분무 및 거동 특성은 가시화 방법과 디지털 화상 처리 기법을 사용하여 분석하였으며, 충돌판 형상의 영향성과 각 형상에 대한 최적 각도 범위를 도출하였다.

선박 디젤 엔진에서 발생하는 대기오염물질 실측에 관한 연구

박진규,임승훈,오정모,Park, Jinkyu,Lim, Seunghun,Oh, Jungmo 해양환경안전학회 2022 해양환경안전학회지 Vol.28 No.6

According to domestic air pollutant emission statistics, a considerable amount of air pollutants is generated by ships. Therefore, various policies are being implemented to limit air pollutant emissions from ships and improve the air quality in ports. In addition, international conventions are carried out for the prevention of marine pollution by ships. However, because few studies and experiments have been conducted on the measurement of air pollutants emitted from actually operating ships, this study presented a method and possibility for evaluating air pollutant emissions from a 9,196GT ship actually operating using a portable emission measurement system (PEMS). A difference in emission occurred depending on the RPM and load, and the emission of NO_X was 497-2,060ppm, CO₂ was 1.55-6.9%, and CO was 0.002-0.14%. The emission specified in the shop test provided by the engine manufacturer differed from the actual emission measured. This study proved that the maximum emission of each air pollutant generated in the entire sailing section of the ship was included in the PEMS measurement range, and the possibility of using PEMS for ships within 10,000GT was verified.

Lean-NOx 트랩의 환원제분무용 Injector의 종류별 분무특성과 NOx저감효율에 관한 연구

한영덕(Youngdeok Han),오정모(Jungmo Oh),이기형(Kihyung Lee),이진하(Jinha Lee) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5

As automotive engine-out emission regulation has been strengthened, after-treatment systems such as LNT and SCR have been studied actively. Lean NOx Trap is one of the best options to reduce NOx emission for diesel engine. LNT need to reduce the agent injection system which has a huge impact on NOx purification efficiency. In this paper, we used two different injectors for the reducing agent and investigated different characteristics of injectors. In addition, the engine emission test was conducted to clarify the effect of these injectors on the NOx reduction. The spray images were taken with a high speed camera, and the spatial distribution of the spray was analyzed using image processing technique. The diesel engine and a gas analyzer were used to investigate the performance of LNT system,

디젤엔진에서 2차 분사조건에 따른 HC-LNT 시스템의 NOx 변환 특성

박진규(Jinkyu Park),오정모(Jungmo Oh),이기형(Jinkyu Park) 한국자동차공학회 2012 한국 자동차공학회논문집 Vol.20 No.5

Automotive engines need strategies to satisfy with the emission regulations in terms of PM and NOx. HC-LNT (Hydrocarbon-Lean NOx Trap) with secondary injection system is considered as more practical technology in order to cope with emission regulations. The HC-LNT system, which is using diesel fuel itself as a reducing agent, absorbs NOx in lean exhaust gas condition and releases NOx in rich exhaust gas conditions. In this system, inappropriate amounts of reducing agent will slip through the LNT without the profits of conversion and cause additional emission problems. Therefore, the suitable amount of reducing agent should be supplied into the catalytic converter. In this research, engine emission test was conducted to optimize injection quantity at the various engine test conditions. Different exhaust layouts and catalyst shapes have been studied and extension unit which makes better uniformity of exhaust gas was used for HC-LNT system. From this results, the effect of secondary injection conditions on NOx conversion characteristics of HC-LNT was clarified.