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가솔린 기관 공연비 제어를 위한 흡기포트 내의 연료액막 모델링
조훈,민경덕,황승환,이종화,Cho, Hoon,Min, Kyoung-Doug,Hwang, Seung-Hwan,Lee, Jong-Hwa 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.4
A wall fuel-film flow model is developed to predict the effect of a wall-fuel-film on air-fuel ratio in an SI engine in transient conditions. Fuel redistribution in the intake port resulting from charge backflow and a simple liquid fuel behavior in the cylinder are included in this model. Liquid fuel film flow is calculated of every crank angle degree using the instantaneous air flow rate. The model is validated by comparing the calculated results and corresponding engine experiment results of a commercial 4 cylinder DOHC engine. The predicted results match well with the experimental results. To maintain the constant air-fuel ratio during transient operation. the fuel injection rate control can be obtained from the simulation result.
이형승,박종범,민경덕,김응서,Yi, Hyung-Seung,Park, Jong-Bum,Min, Kyoung-Doug,Kim, Eung-Seo 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.5
In order to investigate the exhaust structure and secondary oxidation of unburned hydrocarbon (HC) in the exhaust port, concentrations of individual HC species were measured in exhaust process, the degree of oxidation were obtained. Using a solenoid-driven fast sampling system on single-cylinder research engine fueled with 94% propane, the profiles of unburned hydrocarbons (HCs) and non-fuel HCs with a propane fueled engine were obtained from several locations in the exhaust port during the exhaust process. The sampled gases were analyzed using a gas chromatography of HC species with 4 or lesser carbon atoms. The change of total HC concentration and HC fractions of major components through the exhaust port were discussed. The results showed that non-uniform distribution of HC concentration existed around the exhaust valve and changed with time, and that the exhaust gas exhibited nearly uniform concentration profile at port exit, which was due to mixing and oxidation. Also it could be known that bulk gas with relatively high HC concentration came out through the bottom of the exhaust valve. To estimate the mass-based degree of HC oxidation in the exhaust port from measured HC concentrations, a 3-zone diagnostic cycle simulation and plug flow modeling were used. The degree of oxidation ranged between 26 % and 36 % corresponding to the engine operation conditions.
다변수 최적화 기법을 이용한 자동차용 고분자전해질형 연료전지 시스템 모델링에 관한 연구
김한상(Kim, Han-Sang),민경덕(Min, Kyoung-Doug),전순일(Jeon, Soon-Il),김수환(Kim, Soo-Whan),임태원(Lim, Tae-Won),박진호(Park, Jin-Ho) 한국신재생에너지학회 2005 한국신재생에너지학회 학술대회논문집 Vol.2005 No.11
This study presents the integrated modeling approach to simulate the proton exchange membrane (PEM) fuel cell system for vehicle application. The fuel cell system consisting of stack and balance of plant (BOP) was simulated with MATLAB/Simulink environment to estimate the maximum system power and investigate the effect of BOP component sizing on system performance and efficiency. The PEM fuel cell stack model was established by using a semi-empirical modeling. To maximize the net efficiency of fuel cel1 system, multi-variable optimization code was adopted. Using this method the optimized operating values were obtained according to various system net power levels. The fuel cell model established was co-linked to AVL CRUISE, a vehicle simulation package. Through the vehicle simulation software, the fuel economy of fuel cell powered electric vehicle for two types of driving cycles was presented and compared. It is expected that this study tan be effectively employed in the basic BOP component sizing and in establishing system operation map with respect to net power level of fuel cell system.
가시화를 이용한 가솔린 엔진의 실린더 벽면에서의 연료액막 거동 분석
조훈,황승환,이종화,민경덕,Cho, Hoon,Hwang, Seung-Hwan,Lee, Jong-Hwa,Min, Kyoung-Doug 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.10
The investigation of liquid fuel film on the cylinder liner is an essential to understand the engine-out hydrocarbon emissions formation in SI engines. In this research, two-dimensional visualization was carried out to investigate the liquid fuel film on the quartz liner in the optical engine. For this, the optical engine with hydraulic system was designed based on the commercial SI engine. The visualization was based on the laser-induced fluorescence with total reflection technique. Using a quartz liner and a special lens, only the liquid fuel film on the liner was visualized. With using this technique, the distribution of the fuel film on the cylinder liner was measured for different engine conditions and injection timing in the optical engine.
고속응답 CO<sub>2</sub> 분석기의 제작 및 이를 이용한 SI엔진에서의 실시간 배기가스 분석에 관한 연구
송현수,박경석,박동선,민경덕,Song, Hyun-Soo,Park, Kyoung-Seok,Park, Dong-Sun,Min, Kyoung-Doug 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.2
A fast-response $CO_2$ analyzer has been developed for measuring the $CO_2$ concentration during transient condition of a SI engine. The analyzer consists of the non-dispersive infrared absorption method, electrical chopping system and water cooling system. The analyzer has good repeatability, linearity and permissible drift characteristic. Besides, it showed 18ms of a response to measure the $CO_2$ concentration. The fast-response $CO_2$ analyzer was applied to a single cylinder SI engine and the $CO_2$ emission was examined during engine start. Simultaneously, the standard exhaust gas analyzer, which has slow response time, was used for confirming the accuracy of the exhaust gas analysis using the fast-response $CO_2$ analyzer. The developed analyzer showed much faster responsive characteristic than that of a standard analyzer and made cycle by cycle exhaust gas analysis possible. The transient engine operating characteristics will be estimated from the $CO_2$ concentration of engine-out emissions and engine operating variables.
다변수 최적화 기법을 이용한 자동차용 고분자 전해질형 연료전지 시스템 모델링에 관한 연구
김한상(Kim, Han-Sang),민경덕(Min, Kyoung-Doug),전순일(Jeon, Soon-Il),김수환(Kim, Soo-Whan),임태원(Lim, Tae-Won),박진호(Park, Jin-Ho) 한국신재생에너지학회 2005 신재생에너지 Vol.1 No.4
This study presents the integrated modeling approach to simulate the proton exchange membrane [PEM] fuel cell system for vehicle application. The fuel cell system consisting of stack and balance of plant (BOP) was simulated with MATLAB/Simulink environment to estimate the maximum system power and investigate the effect of BOP component sizing on system performance and efficiency. The PEM fuel cell stack model was established by using a semi-empirical modeling. To maximize the net efficiency of fuel cell system, multi-variable optimization code was adopted. Using this method, the optimized operating values were obtained according to various system net power levels. The fuel cell model established was co-linked to AVL CRUISE, a vehicle simulation package. Through the vehicle simulation software, the fuel economy of fuel cell powered electric vehicle for two types of driving cycles was presented and compared. It is expected that this study can be effectively employed in the basic BOP component sizing and in establishing system operation map with respect to net power level of fuel cell system.
고분자전해질형 단위 연료전지의 공기극 유로 채널 내 온도 분포와 플러딩 현상에 관한 연구
김한상(Kim, Han-Sang),하태훈(Ha, Tae-Hun),민경덕(Min, Kyoung-Doug) 한국신재생에너지학회 2006 한국신재생에너지학회 학술대회논문집 Vol.2006 No.11
Water management is considered to be one of the main issues to be addressed for the performance improvement of proton exchange membrane (PEM) fuel cell. For good water management, the detailed information on the water distribution inside an operating PEM fuel cell should be available to main an adequate level of hydration in the PEM While avoiding performance decline due to liquid rater flooding. For the PEM fuel cell to be commercially viable as vehicle applications, the flooding on the cathode side should be minimized during the fuel ceil operation. In this study to investigate cathode flooding and its relation with temperature distribution in flow channels, visualization study was performed on the cathode side of a PEM fuel cell. For the direct visualization of temperature field and water transport in cathode flow channels, a transparent cell was designed and manufactured using quartz window. Water transport and its two-phase flow characteristics in flow channels were investigated experimentally. Also, the visualization of temperature distribution In cathode flow channels was made by using IR camera. Results indicated that the temperature rise near the exit of cathode flow channel was found. It is found that this area corresponds to the flooding area from both temperature and flooding visualization results It is expected that this study can effectively contribute to get the detailed data on water transport linked with heat management during the operation of a PEM fuel cell
당량비 조건에 따른 PEM 단위 연료전지의 과도 응답 특성 및 공기극 플러딩 연구
조준현(Cho, Jun-Hyun),김한상(Kim, Han-Sang),민경덕(Min, Kyoung-Doug) 한국신재생에너지학회 2007 신재생에너지 Vol.3 No.2
The transient response of PEMFC (proton exchange membrane fuel cell) is important criteria in the application of PEM fuel cell to real automotive system. In this work, using a transparent unit PEM fuel cell, the transient response and cathode flooding during load change are investigated. The cell voltage is acquired according to the current density change(0.3Acm² to 0.6A/cm²) under various stoichiometry conditions and different flooding intensities, Also the cathode gas channel images are obtained by CCD imaging system simultaneously. The different level of undershoots appeared at the moment of load changes under different cathode stoichiometries and flooding intensities. It takes about 1s that the product water comes up onto the flow channel so that oxygen supply is temporarily blocked which causes voltage loss in that undershoot. The correlation of the dynamic behavior with stoichiometry and cathode flooding is induced from the results of these experiments.