불꽃점화 반켈 로터리 기관의 성능 시뮬레이션

채재우(J. O. Chae),이상만(S. M. Lee),전영남(Y. N. Chun),김규정(K. J. Kim),정영식(Y. S. Jeong) 한국자동차공학회 1993 한국 자동차공학회논문집 Vol.1 No.1

Performance simulation for a Spark Ignition Wankel rotary Engine is presented in this paper. The volume of chamber at each eccentric shaft angle is evaluated by using geometric models of housing and rotor. A thermodynamic model which includes the first law of thermodynamics. combustion and convective heat transfer from chamber co~tents to surroundings is employed. A thermochemical equilib-rium model which considers 10 species(CO, CO₂, O₂, H₂, H₂O, OH, H, O NO, N₂) in the burned gas region, is also employed. Four processes of gas exchage, compression. combustion and expansion are<br/> considered and the pressure, temperature and composition of chari1ber gas at each eccentric shaft angle in each process are computed in this performance simulation. <br/> This performance simulation must be useful for optimal design of Spark Ignition Wankel Rotray Engine with parametric study for various design parameters and operating conditions.<br/>

다공성물질을 이용한 초단열 연소장치에서의 연소특성의 실험적 연구

채재우,심민섭,정성찬,Chae, J.O.,Dobrego, K.V.,Sim, M.S.,Chung, S.C. 대한설비공학회 1994 설비공학 논문집 Vol.6 No.4

Beacuse of the energy resources exhaustion, the aggravating environmental air pollution and the smoke phenomena etc., the importance of clean gas fuel compared with liquid fuel is highly considered in recent years. The combustion system which consists of porous media is actively studied as a new method for solving above problems. Therefore, excess enthalpy combustion using porous media was interested by many researchers and investigated through numerical and experimental analysis. In this study, the simplified combustor has the unique combustion characteristics of mixture gas preheated effect using radiative and convective heat energy by changing the flow passage of unburned gas with solenoid valves and has the intensive excess enthalpy phenomena As the result of according to reduce equivalence ratio, flame temperature was remarkably higher than adiabatic flame temperature. This show the ability of super-lean combustion.

Ar과 CO₂첨가에 따른 디젤기관의 성능에 관한 연구

정영식(Y. S. Jeong),이상만(S. M. Lee),채재우(J. O. Chae) 한국자동차공학회 1997 한국 자동차공학회논문집 Vol.5 No.4

The re quest to develop the engines that are able to run without air or with very little oxygen condition is raised with the interest of ocean science or the mines. This research had already be gun before the world war Ⅱ, but had been stagnant owing to the appearance of nuclear power. Recycle diesel engines have ability to run under the above -mentioned condition. the recycle diesel engine recirculates exhaust gases into intake port and consumes additional oxygen supplied by oxygen tanle Carbon dioxide is controlled by the absorber. The combustion and emission characteristics of recycle diesel engines are quite different with conventional one because the working fluids of recycle diesel engines consist of Ar, CO₂ and O₂ as well as N₂.<br/> Recycle diesel engine is therefore different with general diesel engine from the viewpoint of intake air composition. It is required to investigate the effect of intake composition on the combustion and emission to know recycle diesel engine. In this study, NOx concentration, smoke and cylinder pressure are measured with the variation of Ar and CO₂ Reduces show that the addition of Ar reduces NOx but increases smoke. Otherwise CO₂ reduces smoke and NOx simultaneously. Only CO₂ increases the ignition delay and both gases increase fuel consumption Ar addition is superior to CO₂addition for the performance of recycle diesel engine system but CO₂has the avantage with respect to emission.<br/>

직접분사식 가솔린기관 개발에 관한 연구(Ⅰ)

채재우(J. O. Chae),이상만(S. M. Lee),차민혁(M. H. Cha),조민수(M. S. Cho),노정용(J. Y. Noh),Li Jianwen(Li Jianwen),정영식(Y. S. Jeong) 한국자동차공학회 1996 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1996 No.11_2

In general, the stratified charge for direct injection gasoline engine should be introduced to achieve ultra-lean combustion. In order to apply for the concept of stratified charge into direct injection gasoline engine, we adopted a reflector inside the cylinder head. An installation of the reflector in front of injector nozzle leads the mixture to be rich near spark plug. As mentioned above, the mixture near the spark plug is locally rich to ignite a fuel while the lean mixture is wholly introduced into the combustion chamber. As a result of the test, ultra-lean comustion could be achieved up to 57 : 1 of AIF ratio without swirl control unit at idle condition. In the case of installation of swirl control unit, considerably extended AIF ratio is expected. So far, the optimizations including analysis of exhaust gases, compromise for conflicting conditions, and fuel injection system have been studied.

성층급기 직접분사식 가솔린기관 개발에 관한 연구 (Ⅱ) -연료분사압력 및 부하변동에 따른 연소특성 해석-

채재우(J.O.Chae),이상만(S.M.Lee),조민수(M.S.Cho),노정용(J.Y.Noh),Li Jianwen(Li Jianwen),정영식(Y.S.Jeong) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.6_1

In general, the stratified charge for direct injection gasoline engine should be introduced to achieve ultra-lean combustion. In order to apply for the concept of stratified charge into direct injection gasoline engine, a reflector was adapted on cylinder head. An installation of the reflector in front of injector nozzle leads the mixture to be rich near spark plug. Therefore, the mixture near the spark plug is locally rich to ignite a fuel while the lean mixture is wholly introduced into the combustion chamber. In this paper, the characteristics of combus­tion is analyzed with the variations of injection pressure and load in a stratified-charge direct injection single cylinder gasoline engine. The results are summarized as follows ;<br/> 1. The MBT spark timing is influenced by engine rpm and load, but has a little relation with fuel injection pressure.<br/> 2. The MBT spark timing is approached to TDC with the increase of load on account of the increase of evaporation energy. Therefore, the peak pressure of cylinder is also delayed with the increase of load.<br/> 3. The stratification effect is cleared with the increase of injection. It is considered by the development of secondary diffusive combustion and the increase of heat release of same region, but proceed rapidly than diesel engine. Specially, in the case of high pressure inj-ection(170bar) and high load(3.0kgf ? m ), the diffusive combustion part is developed ex­cessively and results to the increase of peak pressure than middle load.<br/> 4. The index of engine stability, COV_inwp value, is generally decreased with the increase of load. Finally, the 150bar injection pressure is appeared as optimum in this research.<br/>

직접분사식 가솔린 엔진을 위한 충돌확산형 연소에 관한 연구

채재우(J.O.Chae),이상만(S.M.Lee),조민수(M.S.Cho),노정용(J.Y.Moh),Li Jianwen(Li Jianwen),정영식(Y.S.Jeong) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.11_1

In this study. a new diffusing-oriented spray combustion system for direct injection gasoline engines is refered. New instrument with multi-impingement walls, called the reflector. which is helpful to make air-fuel mixture, is used in this system as a strategy of forming air-fuel mixture. This is attached in front of fuel spray as the scheme of disintegrating fuel droplet injected from multi-hole injector and guiding impinged fuel spray to prefered direction. The impingement wall toward spark plug of reflector is specially designed. So the fuel spray toward spark plug is formed comparatively rich air-fuel mixture and the other fuel spray is formed stratification charge inside combustion chamber. <br/> The combustion system is investigated on a single cylinder four-stroke DI gasoline engine which is modified from a conventional DI diesel engine. The effects of the shape of reflector and injection timing are investigated without throttling on sfc, COV_imp, and HC emissions.<br/>

A NEW METHOD OF INNER-CYLINDER DIAGNOSTIC

채재우(J. O. Chae),최동천(D. C. Choi),문승일(S. L. Moon) 한국자동차공학회 1995 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1995 No.6_1

As a part of further investigations of possibilities to use a spark-plug as a sensor indicating processes taking place in the cylinder of an internal combustion engine we carried out the experimental study of a misfire detection. A new phenomenon -'effect of modulation of breakdown voltage' - was observed. This phenomenon lets us to have a new view on the inner-cylinder processes.<br/>

저온 플라즈마를 이용한 디젤엔진 soot 제거에 관한 연구

채재우(J.O.Chae),황재원(J.W.Whang),김관영(K.Y.Kim),이창신(C.S.Lee),선희석(H.S.Sun),김건우(G.O.Kim) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.5_1

The importance of the elimination of air-pollution caused by the increase of energy demands is requested seriously in these days. Especially, the diesel engine exhaust gas is very harmful and difficult to reduce with current methods. The exhaust gas treatment technology using non-thermal plasma is one of the advanced method, and has advantage of high removal efficiency with low energy consumption. In this study, the experiment is carried with 1 cylinder agricultural diesel engine, and it is shown the soot removal efficiency with various engine R.P.M. and different reactor types(square-shape electrode reactor, planar-type reactor, and mixed type reactor).<br/>

솔레노이드 밸브를 이용한 직접분사식 디젤기관의 분사율 제어 및 배기 저감에 관한 연구

채재우(J.O.Chae),이상만(S.M.Lee),황재원(J.W.Hwang),양이진(I.J.Yang),장석채(S.C.Chang),갈한주(H.J.Kal),정영식(Y.S.Jeong),A.A.Martychenko(A.A.Martychenko),Balin Andrei(Balin Andrei) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.6_1

A very fast solenoid valve has been developed to modulate the pressure of fuel pressure in the injection system of a D.I. Diesel engine. The working process of solenoid has been analyzed and calculated for each characteristic period. The modulated pressure by solenoid valve varies needle lifting process and therefore cause different injection rate. An investigation into the application of electronically controlled solenoid valve to reduce emissions of NOx and soot has been carried out in both conventional and newly designed solenoid valve actuated injection system. Conventional and electronically controlled comparisons of emission products were made under 1500 rpm engine speed, 3/4 load conditions. The outlook for the use of electronically controlled fuel injection technology is described in the light of the results obtained.<br/>

[論文] 연료분사노즐의 니들밸브 형상변화에 따른 분무특성에 관한 연구

채재우(J.O.Chae),임무룡(M.Y.Leem),오신규(S.K.Oh) 한국자동차공학회 1987 오토저널 Vol.9 No.4

The experimental study, using constant pressure injection system, is carried out to inves­tigate the effect of the geometrical shape changes of the needle valve on the effective flow area, the spray angle and the Sauter's Mean Diameter according to needle valve lift for a pintle-type injection nozzle.<br/> The results are as follows:<br/> 1) With the increase of the needle valve lift, the effective flow area is increased, the spray angle is at first increased and later decreased, and the sauter's Mean Diameter is decreased.<br/> 2) It is also shown that the spray angle is maximum at the rapidly increased region of the effective flow area.