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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.
An Objective Method of Driveability Evaluation using a Simulation Model for Hybrid Electric Vehicles
신창우,차석원,최종대,임원식 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.2
Conventionally, driveability evaluations in vehicles are subjectively assessed by professional test drivers in automotive companies. To solve limitation of repeatability and time-consuming, this paper proposes an objective method of evaluating driveability during acceleration and overtaking conditions in a hybrid electric vehicle. Selected criteria are the acceleration value obtained by the root mean square (RMS), the vibration dose value (VDV), the response delay, and the peak-to-peak value of the acceleration and jerk. For human vibration, measured acceleration signals are applied to frequency weighting functions on the basis of ISO 2631-1. An objective evaluation method for driveability is proposed by achieving a synthesis between the values calculated from each criterion and the correlated weighting factor obtained from the regression analysis of the subjective evaluations. The results by the proposed method with the target HEV are compared to those of the subjective evaluations during acceleration condition and while overtaking. A HEV dynamic model is also designed to utilize the proposed method. The characteristics of two types of strategies for HEVs are designed and analyzed. Finally, a driveability evaluation for each control strategy is performed and the results are compared using the proposed evaluation method.
Characteristic Behaviors on Air-breathing Direct Methanol Fuel Cells
장익황,차석원,이민환 한국정밀공학회 2012 International Journal of Precision Engineering and Vol.13 No.7
This paper investigated environmental effects of passive, air-breathing, and vapor-feeding direct methanol fuel cells (PAVDMFCs). In these experiments, main experimental parameters are temperature (30℃, 40℃) and relative humidity (25%,75%). From these experimental results, the humidity plays a key role in terms of the water management at the cathode catalyst layer. During pure methanol feeding, the peak performance shows in relative humidity 25% and 40℃. Under high humidity condition (relative humidity 75%), the water flooding of cathode blocks the oxygen reduction reaction at the cathode. The low humidity (relative humidity 25%) decreases the flooding of the cathode, in which the Warburg of relative humidity 25% decreases rather than that of relative humidity 75%. We concluded that rich water contents of the cathode slightly decrease activation overpotentials.
Development of PMP-based Power Management Strategy for a Parallel Hybrid Electric Bus
정종렬,차석원,Daeheung Lee,김남욱,Chunhua Zheng,박영일 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.15 No.2
To operate a hybrid electric vehicle efficiently, it is important how to manage energy components such as the engine, motor and battery of the vehicle. In this paper, the Pontryagin's minimum principle (PMP) based power management strategy is developed and applied to a forward simulation program able to calculate the fuel economy of a vehicle with its specified driving cycle. Typical two other power management strategies, the Max state of charge (SOC) power management strategy and the power split ratio rule-based power management strategy are also developed and applied to verify the application possibility of the PMP-based power management strategy. A simulated comparison of the power management strategies using six driving cycles is conducted. As a result, considering the characteristics of buses which drive a routine cycle repeatedly, the PMP-based power management strategy, which shows the most efficient performance with respect to the fuel economy and the maintenance of the battery SOC, is more appropriate than the other power management strategies while the application of PMP-based power management strategy to a conventional vehicle has a difficulty because of the problem about maintenance of the battery SOC.