DME 직접분사식 압축착화 엔진에서 파일럿 분사의 영향

윤현숙(Hyeonsook Yoon),배충식(Chongsik Bae) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

The dimethyl-ether (DME) combustion with pilot injection was investigated in a single cylinder direct injection diesel engine equipped with the common-rail injection system. Combustion performance and emissions were tested with dimethyl-ether. The main injection timing was at the top dead center, which were the best timings for maximum power output. The total injected fuel mass was fixed 22㎣ per cycle at 800 rpm. The fuel quantity and the injection timing of the pilot injection were varied from 8 to 20% of the total injected mass and from 50 to 10 crank angle degree before the main injection timing, respectively. The ignition delay decreased with the pilot injection. The indicated mean effective pressure increased when dimethyl-ether was pilot-injected at 20 crank angle degree before the main injection timing. DME showed reduction in emissions, such as particulate, hydrocarbon, carbon monoxide and nitric oxides. The hydrocarbon and the carbon monoxide emissions were increased when the pilot injection timing was advanced. The nitric oxide emission was increased by 14% with 8% of pilot injection. Bigger amount of DME pilot-injection decreased nitric oxide emission.

Poly(ethylene glycol) Dimethyl Ether에 대한 이산화탄소의 용해도

이은주 ( Eun-ju Lee ),유정덕 ( Jung-deok Yoo ),이병철 ( Byung-chul Lee ) 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.2

약 303 K로부터 약 343 K의 온도 범위와 약 50 bar까지의 압력 범위에서 poly(ethylene glycol) dimethyl ether(PEGDME)에 녹는 이산화탄소(CO₂)의 용해도를 측정하였다. 가변부피 투시창이 장착된 고압용 상평형 장치를 사용하여 온도를 변화시키면서 여러 가지 조성을 갖는 CO₂+PEGDME 혼합물의 기포점 압력을 측정함으로써 PEGDME에서의 고압 CO₂의 용해도를 결정하였다. PEGDME의 분자량이 CO₂ 용해도에 미치는 영향을 관찰하기 위하여, 두 가지 종류의 분자량을 가진 PEGDME 시료에 대한 CO₂ 용해도를 비교하였다. 압력이 증가함에 따라 PEGDME에 대한 CO₂ 용해도는 증가하였으며 온도가 증가함에 따라 용해도는 감소하였다. 같은 온도와 압력에서 비교할 때, 분자량이 더 큰 PEGDME는 질량분율과 몰랄농도 기준으로 더 작은 CO₂ 용해도를 주었으나, 몰분율 기준으로는 더 큰 CO₂ 용해도를 주었다. Solubility data of carbon dioxide (CO₂) in poly(ethylene glycol) dimethyl ether (PEGDME) are presented at pressures up to about 50 bar and at temperatures between 303 K and 343 K. The solubilities of CO₂ were determined by measuring the bubble point pressures of the CO₂ + PEGDME mixtures with various compositions using a high-pressure equilibrium apparatus equipped with a variable-volume view cell. To observe the effect of the PEGDME molecular weight on the CO₂ solubility, the CO₂ solubilities in PEGDME with two kinds of molecular weight were compared. As the equilibrium pressure increased, the CO₂ solubility in PEGDME increased. On the other hand, the CO₂ solubility decreased with increasing temperature. When compared at the same temperature and pressure, the PEGDME with a higher molecular weight gave smaller CO₂ solubility on a mass fraction and molality basis, but gave greater CO₂ solubilities on a mole fraction basis.

Enhancement of dimethyl ether production with application of hydrogenpermselective Pd-based membrane in fluidized bed reactor

Mohammad Reza Ehsani,Mohammad Mahdi Mardanpour,Roohollah Sadeghi,Mohsen Nasr Esfahany 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.3

A two-phase model for a novel shell and tube fluidized bed membrane reactor has been developed in order to synthesize the dimethyl ether. Due to the hydrogen partial pressure driving force, hydrogen can penetrate from feed synthesis gas, flowing in the shell side, into the reaction side through the membrane. The proposed model has been used to compare the performance of a fluidized bed membrane reactor with the conventional reactors. The effects of different parameters on the dimethyl ether production and CO conversion were investigated. The results show an increase in DME production and CO conversion by permeation of hydrogen.

2단 연료 분사를 통한 DME 예혼합 압축착화 엔진 연소 개선

윤현숙(Hyeonsook YOON),배충식(Choongsik Bae) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.41

Premixed charge compression ignition combustion with a two-stage fuel injection strategy using dimethyl-ether, a gaseous fuel and diesel, a liquid fuel, was investigated in a single cylinder direct-injection compression-ignition engine. The combustion performance and exhaust emissions were tested by varying the second injection timing for dimethyl-ether and diesel respectively. The experiments were carried out under low load and low speed conditions. The first injection was injected at the early stage of the compression stroke to gain enough time for premixed mixture formation. The injected fuel quantity of the first injection was varied corresponding to the fixed load. A small quantity of second injection was applied to control the premixed charge combustion with various timings near the top dead center. With the second injection near the top dead center, the combustion efficiencies improved for both dimethyl-ether and diesel. By the late second injection, the combustion phase was retarded and lengthened, and hydrocarbon and carbon monoxide emissions were reduced.

Dimethyl Ether-Air 예혼합화염의 축소 반응 메카니즘 개발

이기용(Ki Yong Lee),이수각(Su Gak Lee) 한국연소학회 2012 KOSCOSYMPOSIUM논문집 Vol.- No.45

A short reaction mechanism was developed in order to predict the flame phenomena in premixed Dimethyl Ether-Air flame with the methods of SEM-CM(Simulation Error Minimization Connectivity Method), sensitivity analysis, and the rate of production analysis. It consisted of 31 species including nitrogen as inert gas and 177 elementary reactions. The flame structures obtained using a detailed reaction mechanism and the short reaction mechanism were compared with various equivalence ratios and pressure, and the results were in good agreement. Therefore, the short reaction mechanism would be used to aim at studying the development of a reduced reaction mechanism.

Experimental investigation of the use of the dimethyl ether/polymer hybrid as a novel enhanced oil recovery method

Mohammad Chahardowli,Rouhi Farajzadeh,Hans Bruining 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.38 No.-

Injection of dimethyl ether (DME) dissolved in water can enhance the recovery efficiency with respect towater flooding. In this Shell Proprietary Technology, DME partitions from water into the oil; decreases oilviscosity and increases its volume, and mobilizes the trapped oil again. In this work, DME-enhancedwater flooding is combined with polymer and considered for cases in which a favorable mobility controlbetween water and oil does not exist. In order to reduce the remaining oil, slugs of the mixed solution ofDME and polymer were injected into the cores containing oil and then followed by injection of a chasefluid. This recovery method benefits both (a) from the presence of polymer, and the oil viscosityreduction caused by DME dissolution and (b) from oil swelling due to DME dissolution. It appears fromexperimental data that the injectivity of a DME/polymer (DMEP) solution is higher than the injectivity ofa polymer solution without DME; this indicates the presence of DME can reduce the viscosifying effect ofthe polymer. The main experimental observations are: (1) a higher oil recovery is obtained fromcontinuous DMEP flooding than from continuous DME–brine flooding, (2) the presence of polymer in theDME slug and in the chase phase reduced the remaining oil after a finite slug injection, and (3) a largerDME slug and mobility control of the chase phase can improve the oil recovery after a finite sluginjection. In summary, the experiments show that combining polymer and DME improves the ultimaterecovery significantly and shortens the duration of oil production.

Effect of ethanol fraction on the combustion and emission characteristics of a dimethyl ether-ethanol dual-fuel reactivity controlled compression ignition engine

Park, S.H.,Shin, D.,Park, J. Applied Science Publishers 2016 APPLIED ENERGY Vol.182 No.-

<P>The purpose of this study was to investigate the effect of the ethanol fraction on the combustion and exhaust emissions characteristics of dimethyl ether (DME)-ethanol dual-fuel reactivity controlled compression ignition (RCCI) engine. In this study, a modified single-cylinder diesel engine was used. The main parameters of this study were the in-cylinder injection timing of DME and the ethanol fraction. The ethanol fraction was found to have a more obvious effect on the indicated mean effective pressure (IMEP) for advanced in-cylinder injection timings than around the top dead center (TDC) conditions. For the same ignition timing, the ethanol fraction had little influence on the IMEP. Increasing the ethanol fraction induced an increase in combustion duration and a decrease in premixed combustion duration (CA10-CA50) around the TDC injection condition. The effect of ethanol on P-max was insignificant for CA50. The application of the DME-ethanol dual-fuel combustion strategy caused a significant reduction of ISNOx without deterioration of ISsoot. In addition, a high ethanol fraction led to a low ISNOx for the same premixed combustion duration. The ISHC and ISCO emissions increased slightly with increasing ethanol fraction for DME-ethanol dual-fuel combustion. However, the emissions from DME-ethanol combustion were lower than those obtained previously with biodiesel-ethanol and diesel-ethanol dual-fuel combustion. (C) 2016 Elsevier Ltd. All rights reserved.</P>

함산소 대체연료 dimethyl-ether (DME)의 분무 및 연소 특성에 관한 연구

박수한 ( Su Han Park ),김형준 ( Hyung Jun Kim ),김세훈 ( Se Hun Kim ),이창식 ( Chang Sik Lee ) 한국액체미립화학회 2009 한국액체미립화학회 학술강연회 논문집 Vol.2009 No.-

Dimethyl-ether (DME) 연료의 분무, 연소 및 배기 특성에 관한 실험 및 수치해석적 연구

박수한 ( Su Han Park ),김형준 ( Hyung Jun Kim ),이창식 ( Chang Sik Lee ) 한국분무공학회 2010 한국액체미립화학회지 Vol.15 No.1

다단분사를 사용한 경량 DME 엔진의 연소제어에 관한 연구

정수진(Soo-Jin Jeong),오세두(Se-Doo Oh),박정권(Jeong-Kwon Park) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5

Dimethyl-ether(DME) is one of the most promising alternative fuels for IC engines. In this study, the compression ignition combustion fueled with dimethyl-ether was investigated. Three-point split injection strategy was applied and evaluated its availability and performance in terms of emission(CO, HC, NOx, PM), fuel economy and power. Experiments were carried out in 4-cylinder 2.9 liter direct-injection diesel engine equipped with common-rail injection system, and the engine performance and emission characteristics were tested the various pre and pilot injection timings and quantities. Experiments were performed under the engine condition ranging from 1200rpm, 2bar to 3000rpm,4 bar. From the results of this study, three-point split injection strategy showed the possibility to overcome the disadvantages of DME engine such as high NOx and HC emissions due to long injection duration for attaining diesel equilibrium performance. By optimizing pre and pilot injection timing and quantities NOx emission could be reduced by maximum 68.5% for low speed and load conditions. Additional NOx reduction of could be obtain by retarding main injection timing. Torque could be improved by reducing injection dwell timing between pilot and main injection. In the range of medium and high load and speed conditions, main injection timing was retarded for reducing NOx emission with sacrificing torque. However, this torque reduction could be compensated by reducing pilot injection quantity and increasing the quantity of main injection.