• 한국도로학회논문집
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• 제10권2호
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• pp.57-67
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• 2008

현재 우리나라에서 도로 평면선형 설계를 위해 도로설계속도 개념을 사용하고 있다. 도로설계속도 개념은 단 한 개 도로 설계속도를 사용하기 때문에 도로 기하구조 수준이 일정해진다는 강점을 갖고 있으나, 도로 건설 후 그 도로를 주행하는 실제 차량 속도가 설계속도와 달리 나타날 수 있다는 약점을 갖고 있기도 하다. 본 연구에서는 이 약점을 보완하기 위해, 이미 여러 나라에서 사용 중인 주행속도 예측모형에 근거한 평면 선형설계기법을 제안한다. 본 연구에서는 이를 위해 우리나라 전역에서 표본을 선택하여 차량 속도조사를 수행했고, 속도에 영향을 미치는 도로설계요소를 통계분석을 통해 선정하여 양방향 2차로와 4차로 일반국도에 대한 차량 주행속도 모형을 제시했으며, 그 모형을 도로 평면선형설계에 적용하는 과정을 제시했다. 한편 새로운 기법에 대한 유효성을 밝히기 위한 실제 사례분석에서 새로운 기법은 기존 기법이 갖고 있는 약점을 해소하는 것으로 밝혀졌다. 향후 우리나라 도로 건설 사업에서 본 연구에서 제안한 평면선형 설계기법을 적용하면 도로 투자 효율성이 높아지고, 더 높은 설계일관성을 확보할 수 있을 것으로 판단한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.816-822
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• 2005

High speed trains with maximum speed of 300km/h, named KTX, have started revenue services since April 2004. Is becoming big problem where currently the KTX train because excessive braking noise at a station platform. The KTX braking noise follows in operating mode of KTX train and important railroad station where the quality appears different, the quality against hereupon from the commerce vehicle from the research which it sees it executes and comparison to analyze.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.170-175
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• 2003

A control algorithm is developed for highly efficient operation of auxiliary power unit (APU) that consists of a diesel engine and a directly coupled induction generator in series hybrid electric Bus (SHEB). In a series hybrid configuration the APU supplies the electric power needed for maintaining the state of charge (SOC) of the battery unit in various conditions of vehicle operation. As the rotational speed of generator does not depend on the vehicle speed, an optimized operation of engine-generator unit based on the efficiency map of each component can be achieved. The output torque of diesel engine can be controlled by the amount of fuel injection, and the power converted from mechanical to electrical energy can be adjusted by generate control unit (GCU) using the decoupling vector control of torque and flux. As for the given reference of the generating power, the multiply of speed and torque, many combinations of operating speed and torque are possible. The algorithm decides the new operating point based on the engine efficiency map and generator characteristic curve. During the transition of operating points, the speed controller saturation is avoided using variable limit and filtering of generator torque reference. A test rig and SHEB consist of a 1.5L diesel engine and a 30kw induction generator are constructed by Hyundai Motor Company.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.675-678
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• 2004

Comparative analysis it did the interior noise of the KTX vehicle and the P-P Semaeul vehicle from the conventional line Homan Seodaejeon-Hanam section from the research which it sees. The test result KTX vehicle appeared when the P-P Semaeul vehicle compared to 20 - 25 KM/H speed up operating commerce operation speed even, the standard values 66 dBA the lowers 55 - 62 dBA. P-P Semaeul vehicle interior noise of the identical test section 63 dBA it will compare and there is a possibility the KTX vehicle knowing from the existing line operating hour interior noise.

• Tribology and Lubricants
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• 제36권2호
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• pp.96-104
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• 2020

The electric vehicle industry is rapidly developing because of enforced environmental regulations, and several studies have been conducted on the multispeed transmission to improve the fuel efficiency of electric vehicles. Among these studies, research on the power density improvement of electric vehicle transmission is critical. Thus, the optimal design of the gear train is necessary to enhance transmission efficiency. In this study, an optimal design methodology for the lightweight two-speed transmission of electric vehicles is proposed. Because a multispeed transmission has many operating conditions and equality and inequality constraints, a new gear design method that combines analytical and iterative methods is applied without using complex optimization algorithms. Sets of possible design variables are generated considering the operating conditions and various design variables. The modules and face width ratios of each stage gear that satisfy the corresponding operating conditions are analytically calculated. The volume of the gear train is calculated, evaluated, and arranged using these values to determine the optimal solution for minimizing the volume, and the proposed methodology is applied to the actual model to verify its effectiveness. The design of a two-speed transmission with multiple operating conditions and constraints without complicated optimization algorithms can be optimized.

• 대한교통학회지
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• 제23권7호
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• pp.17-33
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• 2005

도로설계속도는 해당도로 규격을 결정하는 매우 중요한 설계요소이다. 설계속도 결정시 개통후 차량 주행속도를 예측하여 상관성이 높도록 계획해야 하는데, 기존 일반국도 주행속도 예측 모형은 설계속도에 따른 기하구조 요인만을 고려하여 도로의 주변환경을 고려하지 못하는 한계가 있다. 주변환경을 충분히 고려하지 않을 경우 과도한 공사비 지출과 지나친 환경 파괴우려가 있다. 따라서 본 연구에서는 도로 주변환경요소를 고려하는 주행속도 예측모형식의 정립을 시도했고, 연구결과는 다음과 같다. 첫째, 우리나라 일반국도의 지형 및 지역 요소를 운전자의 시각 특성과 GIS 프로그램을 활용하여 정의하였다. 둘째, 이렇게 구축한 지형 및 지역 특성이 차량의 주행속도에 미치는 영향을 살펴보았다. 그 결과, 지형 및 지역 별로 95% 신뢰도에서 속도차이가 있는 것으로 판단되었다. 섯째, 일반선형 모형(GLM)을 통하여 기하구조 요인과 지형 및 지역 요인을 모두 고려한 예측 모형식을 수립해 보았는데, R-Square가 양방향 2차로는 0.67, 양방향 4차로가 0.85로 나타났다. 끝으로 본 연구에서 개발한 모형을 바탕으로 지형 및 지역요소를 감안한 적정 도로 설계속도 범위를 제시했다. 이 방법론에 따라 산출된 관련 설계속도 범위는 일반국도에 대해 적용할 수 있지만, 지방도등 타 도로에 대해서는 직접 적용하기 곤란하다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.245-250
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• 2006

From the research which it sees the safety regarding a high-speed railway vehicle collision and a derailment evaluation research it an example and executed. Japan, France, Germany and Spain, Italy and with our country together it compared a high-speed railway vehicle collision of the high-speed railroad operating nation and derailed relation safety standard and safety against the evaluation system trade name comparison it analyzed. The research which it sees it led and the accident instance against the hazard analysis against the collision and a derailment of the high-speed railway vehicle and a risk evaluation together and a high-speed vehicle collision and derailed it cannot prevention plan from hereafter domestic comparison it analyzed forecast it presented.

• 한국자동차공학회논문집
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• 제13권3호
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• pp.35-40
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• 2005

In the present study, the influence of operating conditions on fuel economy for hybrid electric vehicle was analyzed. In order to accomplish this, vehicle speed, engine speed, battery current and voltage, SOC (state of charge),motor speed and torque, generator speed and torque, engine coolant temperature etc. were measured in real time. The tests were carried out under different driving cycles which are urban and highway cycles, KOREA CITY cycle and on-road driving, and also under various operating conditions such as different initial SOC, with or without regenerative braking etc.. Generally, conventional gasoline engines show a poor fuel economy at stop and go driving, because braking energy is wasted and the engine is operated in low thermal efficiency regions. However, in case of hybrid vehicles, higher fuel economy can be obtained because of utilizing the maximum thermal efficiency regions of engine, idling stop of engine, and regenerative braking etc..

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집 특별세미나,특별/일반세션
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• pp.217-222
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• 2009

High-speed EMU under development vibrates more than a articulated high-speed train since power units are attached on each vehicle and railway vehicle. In this study, anisotropic equivalent stiffness of a aluminum extrusion plate were calculated to know and predict vibration characteristic of High-speed EMU under development. Eigen frequencies and modal shape of high speed train vehicle were calculated. And vibration generated was predicted at each position of vehicle when vehicle was operating.

• 한국분무공학회지
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• 제28권2호
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• pp.62-67
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• 2023

Recently, the global automobile industry is aiming for a transition from internal combustion locomotives to zero-emission vehicles. Electric vehicles powered by battery energy can operate at peak performance and improve fuel economy by applying multiple motors or multi-speed transmissions. In order to design a two-speed transmission, it is necessary to evaluate and analyze the application system and performance of electric vehicles. In this study, control performance optimization of a twostage battery electric vehicle equipped with an AMT-based automatic transmission was performed and performance according to control pattern changes was analyzed. In order to improve the operating efficiency of the motor, the shift control that sets the optimal operating point according to the vehicle speed and required torque was derived from the motor efficiency map. The performance of battery energy consumption and transmission loss energy according to the hysteresis interval was analyzed and optimized. The hysteresis interval applied to the optimal shift map acted as a factor in reducing the frequency and loss of shifts. It has been shown that keeping the hysteresis interval at about 4 km/h can reduce energy consumption while reducing the number of shifts.