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차석원(Suk Won Cha),정종렬(Jongyul Jeong),서호원(Ho Won Seo),하승범(Seungbum Ha) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
It is critical that design engineers in a global business corporation collaborate efficiently with colleagues in branch offices located all over the world. This study discusses how students can be trained for such activity through a global design class. Students from three universities form a design team to perform a product design and prototyping. Student communication among universities is typically achieved by internet-based telecommunication systems that provide audio and video signal. Language, cultural difference and time difference pose a huge challenge to efficient team building. The lecturers play a key role in resolving conflicts between team members. Regardless of the outcome, students appreciate the global design experience under proper environment organized by the lectures.
맥동 효과를 이용한 dead-end type 연료전지의 성능향상에 대한 실험적 연구
최종원(Jong Won Choi),서정훈(Jeong-hoon Seo),황용신(Yong-Sheen Hwang),이대흥(Dae Heung Lee),차석원(Suk Won Cha),김민수(Min Soo Kim) 대한설비공학회 2008 대한설비공학회 학술발표대회논문집 Vol.2008 No.2
PEM Fuel Cell operation mode can be classified into dead-end mode or open mode by whether the outlet port is blocked or not. Generally, dead-end type fuel cell has some merits on the pressure drop and system efficiency because it can generate more power than the open type fuel cell due to high operating pressure condition. However, the periodic purging process should be done for removing water which is formed as product of a reaction in the gas diffusion layer. In this study, cathode side dead-end type operation has been conducted. Moreover, pulsating flow generator at the outlet of cathode side has been suggested for increasing the period to purge the formed water because the pulsating flow can make formed water scattered uniformly over the whole channel. As a result, the purging period with pulsation increased by 1.5-2 times longer than that without pulsating.
산업차량용 토크컨버터의 작동 안정성 평가 방법에 대한 연구
김범수,임원식,차석원,Kim, Beom-Soo,Lim, Won-Sik,Cha, Suk-Won 한국자동차공학회 2007 한국 자동차공학회논문집 Vol.15 No.3
This paper presents the induced mathematical modeling equations for evaluating the operation stability with automatic transmission of heavy duty vehicle. This theoretical approach indicates that linearized governing equations of system can be converted into eigen-value problems. if the eigen-value has positive number, we can predict the engine operating point locates an unstable operating region. To be a stable state, the unstable operating point diverges toward a stable point which is able to maintain uniform velocity. Based on the previous theoretical analysis, we carry out dynamic simulation to show the behavior of engine operating point and torque converter in transient state. As a result of the dynamic simulation, the suggested theoretical method is found to be reasonable for evaluating the operation stability of a torque converter. In addition, the numerical results explain the engine stops and fluctuating phenomenon in reality.
서호원(Ho Won Seo),이대흥(Dae Hueng Lee),차석원(Suk Won Cha) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
The registration of mopeds and motorcycle is increasing early. With compare to gasoline and diesel passenger car, mopeds and motorcycle generates more emission gas. So it is important to develop motorcycle with hybrid powertrain. With hybrid electric powertrain, mopeds and motorcycles might have better fuel economy and less emission gas. This paper proposes control strategies of 3Wheel hybrid electric vehicle. For develop the control strategies, two vehicle models are constructed. One is conventional internal combustion engine type vehicle model and another is hybrid electric vehicle model(HEV). HEV model is constructed with electric components like motor and battery. A test vehicle is constructed to develop 3W HEV.
Fixed time step solver 기반의 클러치 수치 해석 기법 개발
서호원(Ho Won Seo),임원식(Won Sik Lim),이대흥(Dae Hueng Lee),차석원(Suk Won Cha) 한국자동차공학회 2010 한국자동차공학회 부문종합 학술대회 Vol.2010 No.5
It is important to develop a model that can characterize dynamic features of transmission in shifting phase to evaluate performance of a controller for an automatic transmission system. And it is very essential to develop a technique that realize dynamic features of clutches that construct a transmission to develop that model. Moreover that model needs to be simulated in real time or semi-real time. But other dynamic analytic simulator software like MSC.ADAMS or AMESim can’t satisfy that feature. So in this research we develop a clutch analisys method that determines stick and slip state of clutches included in a transmission based on fixed step solver.
Jaewon Hwang(황재원),Suk Won Cha(차석원) 한국신재생에너지학회 2021 한국신재생에너지학회 학술대회논문집 Vol.2021 No.7
Ni-Gd doped Ceria (GDC) cermet is a widely used anode material in the field of thin-film solid oxide fuel cells (TF-SOFC). When Ni-GDC cermet anode is fabricated as thin film by deposition methods such as sputtering and pulsed laser deposition, a sufficient amount of GDC is necessary as high composition of ceramic materials, typically less mobile than metals, can suppress thermal agglomeration of metals by inhibiting its mass transport. However, achieving such GDC composition is difficult using the co-sputtering method since ceramic targets exhibit considerably lower sputtering yield compared to metal targets. This is also in part due to the inherent limitation of the sputtering technique as high electrical power cannot be applied to ceramic targets. In this study, Ni-GDC anode with GDC composition of more than 20% was fabricated by co-sputtering Ni target and GDC ceramic target and controlling the glancing angle. Rotation of the substrate was suppressed to obtain uneven incident angles of Ni and GDC vapor. As a result, Ni deposition rate was reduced by half while GDC deposition rate was maintained. Electrochemical examination of the TF-SOFC utilizing the as-fabricated anode was done via methods such as EIS and LSV at 600℃.
A study for gas distribution in separators of molten carbonate fuel cell
박준호(Park, Joonho),차석원(Cha, Suk Won) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11
A channel design which is closely related with the mass transport overpotential is one of the most important procedures to optimize the whole fuel cell performance. In this study, three dimensional results of a numerical study for gas distribution in channels of a molten carbonate fuel cell (MCFC) unit cell for a 1kW class stack was presented. The relationship between the fuel and air distribution in the anode and cathode channels of the unit cell and the electric performance was observed. A charge balance model in the electrodes and the electrolyte coupled with a heat transfer model and a fluid flow model in the porous electrodes and the channels was solved for the mass, momentum, energy, species and charge conservation. The electronic and ionic charge balance in the anode and cathode current feeders, the electrolyte and GDEs were solved for using Ohm's law, while Butler-Volmer charge transfer kinetics described the charge transfer current density. The material transport was described by the diffusion and convection equations and Navier-Stokes equations govern the flow in the open channel. It was assumed that heat is produced by the electrochemical reactions and joule heating due to the electrical currents.