• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.683-686
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• 2004

In recent years, the supercapacitor and hybrid capacitor have related with substitutional energy source focused of many scientists because of their usage in power sources for electric vehicles, computers and other electric devices. The storage energy of electrical charge is based on electrostatic interactions in the electric double layer at the electrode/electrolyte interface, resulting in high rate capability and long cycle performance compared with batteries based on Faradaic electrode reactions. So we have been considered to carbon nanofibers as the ideal material for supercapacitors due to their high utilization of specific surface area, good conductivity, chemical stability and other advantages. In this work, we aimed to find out that the capacitance have increased because of electrochemical capacitance to provide by carbon nanofibers. Also carbon nanofibers based on chemical method and water treatment have been resulted larger capacitances and also exhibit better electrochemical behaviors about 15% than before of nontreated state. And also optical observations with treated and nontrteated carbon nanofibers discussed by the TEM, SEM, EDX, BET works and specific surface area analyzer. Their results also focused on the surface area of electrode and electrical capacitance was also improved by the effect of surface treatments.

• 한국ITS학회 논문지
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• 제10권5호
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• pp.113-123
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• 2011

최근 온난화 문제가 대두됨에 따라 세계 각국에서 $CO_2$ 배출감소를 위한 여러 가지 규제를 설정하고 있다. 특히 수송부분에서의 $CO_2$ 배출량 감소는 매우 영향력이 크므로 자동차 산업에서도 전기자동차를 비롯한 그린자동차 개발에 대한 관심이 높아지고 있다. 이에 따라 전기자동차 시대 도래 대비를 위하여 전기자동차 보급에 따른 인프라 구축 전략안 및 전력량 수요 예측이 필요하지만, 이의 기반이 되는 전기자동차 수요예측 방법은 소개되어 있지 않고 있다. 따라서 본 연구에서는 선택기반 다세대 확산모형을 이용하여 전기자동차의 수요를 예측하는 방법론을 제시하였다. 전기자동차와 비슷한 성격을 가지는 하이브리드 자동차의 과거 데이터를 이용하여 Bass 모형의 혁신계수와 모방계수를 추정하고 SP(Stated Preference)조사를 통하여 잠재적인 총수요를 추정함으로써 전기자동차의 수요를 년도별로 예측하였다. 또한, 전기자동차가 발전하는 속성 진화에 따른 다세대 확산과정을 모형에 반영하여 보다 정확한 수요예측이 가능하도록 하였다. 본 연구의 수요예측 방법론을 통하여 향후 전기자동차의 시장 점유율을 예측함으로써 전기자동차 보급과 밀접한 관련이 있는 전력수급 및 충전인프라 구축 연구에 활용 될 수 있도록 한다.

• 항공우주시스템공학회지
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• 제14권5호
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• pp.42-48
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• 2020

본 논문은 2행정 피스톤 엔진 기반 발전기 및 배터리로 구성된 드론용 전기추진시스템 설계 과정에 대해 다룬다. 연구의 목적은 하이브리드 시스템의 높은 에너지 밀도를 이용하여 비행시간을 증가 시키고 화석연료 사용량을 줄임으로써 환경 변화에 대처함에 있다. 시스템은 6 kW의 출력을 생산할 수 있고, 엔진 RPM 제어를 통해 부하 요구에 맞는 출력 조절이 가능하다. 또한 배터리를 추가 장착함으로써 출력 보완재 역할 뿐만 아니라 비상시 제한된 시간 내 주 전력으로 사용할 수 있다. 또한 발전기를 엔진 크랭크축에 직접 연결함으로써 설계 복잡성을 줄여 동체 내 공간 활용성을 증대 시켰다.

• 한국자동차공학회논문집
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• 제18권4호
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• pp.84-91
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• 2010

Owing to revolutionary developments in automobile technologies, a variety of advanced vehicles - hybrid vehicle, hydrogen fuel-cell vehicle, electric vehicle, etc. - emerges recently. The safety is getting more important for developing automobiles. The electro-magnetic compatibility has to be assured, since those advanced vehicles are equipped with various new electronic systems. Electro-magnetic compatibility tests, in general, consist of an EMI(electro-magnetic interference) test and an EMS (electro-magnetic susceptibility) test. We investigated the susceptibility test method suggested in KMVSS (Korean Motor Vehicle Safety Standard) as the EMS test method. A series of experiments results that the above test method should be partially revised to comply with a Korean governmental standard method. In this paper, the some directions of modifications are presented to enhance the quality of the above EMS test method.

• Applied Science and Convergence Technology
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• 제23권2호
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• pp.72-82
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• 2014

Lithium-ion batteries (LIBs) have become popular electrochemical devices. Due to the unique advantages of LIBs in terms of high operating voltage, high energy density, low self-discharge, and absence of memory effects, their application range, which was primarily restricted to portable electronic devices, is now being extended to high-power applications, such as electric vehicles (EVs) and hybrid electrical vehicles (HEVs). Among various anode materials, $Li_4Ti_5O_{12}$ (LTO) is believed to be a promising anode material for high-power LIBs due to its advantages of high working potential and outstanding cyclic stability. However, the rate performance of LTO is limited by its intrinsically low electronic conductivity and poor $Li^+$ ion diffusion coefficient. This review highlights the recent progress in improving the rate performance of LTO through doping, compositing, and nanostructuring strategies.

• 소성∙가공
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• 제32권3호
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• pp.122-128
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• 2023

As electric vehicles (EV) have increasingly replaced the conventional vehicles with internal combustion engines (ICE), most of automotive makers are actively devoting to the technology development of EV parts. Accordingly, the manufacturing process for power source has been also shifting from engine/transmission to EV motor/reducer system. However, lack of experience in developing the EV motor still remains as a technical challenge. In this paper, we employed the forming simulation based on finite element modeling to solve this problem. In particular, in order to increase the accuracy of the forming simulation, we introduced the elastic-plastic constitutive model parameters for polymer-copper hybrid wire by investigating the individual strain-stress curves, and elastic modulus of polymer and copper. Then, the reliability of modeling procedure was confirmed by comparing the simulated results with experiments. Finally, the identified mechanical properties and finite element modeling were applied to a hairpin forming process, which involves multiple deformation paths such as bending, pressing, widening, and twisting. The proposed numerical approach can replace common experience or experiment based trials by reducing production time and cost in the future.

• Smart Structures and Systems
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• 제32권6호
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• pp.393-402
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• 2023

Recently, hybrid and electric vehicles have been actively developed to replace internal combustion engine (ICE) vehicles. However, their vibrations and noise with complex spectra cause discomfort to drivers. To reduce the vibrations transmitted through primary excitation sources such as powertrains, structural changes have been introduced. However, the interference among different parts is a limitation. Thus, active mounting systems based on smart materials have been actively investigated to overcome these limitations. This study focuses on diminishing the source movement when a structure with two active mounting systems is excited to a single sinusoidal and a multi-frequency signal, which were investigated for source movement reduction. The overall structure was modeled based on the lumped parameter method. Active vibration control was implemented based on the modeled structure, and a multi-normalization least mean square (NLMS) algorithm was used to obtain the control input for the active mounting system. Furthermore, the performance of the NLMS algorithm was compared with that of the quantification method to demonstrate the performance of active vibration control. The results demonstrate that the vibration attenuation performance of the source component was improved.

• 한국산학기술학회논문지
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• 제15권6호
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• pp.3357-3362
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• 2014

본 연구에서는 자동차가 노면을 주행 시 발생되는 진동에너지를 수집하여 차량의 배터리를 자가 충전할 수 있는 현가장치에 적용 가능한 공진형 선형 발전시스템을 설계하였다. 논문에서 제안된 선형 발전기는 기존의 발전기들과는 달리, 비교적 작은 에너지 원천인 노면의 진동에 더욱 효과적으로 대응하기 위해 공진 현상을 최대한 활용하는 설계를 지향했으며, 한정된 공간인 차량 현가장치에서의 선형 발전기의 발전 효과 검증 및 향후 연구 진행의 가능성을 판단하기 위해 수치해석적 방법을 활용하여 시스템의 동적 해석을 위한 기본 입력 속도를 도출하고 시스템의 목표인 발전 기능에 대한 예측을 위해 전자기 유한요소해석을 수행하였다. 본 연구에서 정상적인 발전 기능의 가능성을 확인한 공진형 선형 발전 시스템이 최근 자동차 산업의 큰 주축을 이루고 있는 하이브리드형 자동차 및 전기 자동차에 적용된다면, 각종 전장장치 및 배터리의 구동 및 성능유지에 도움을 줄 수 있을 것이다.

• 제어로봇시스템학회논문지
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• 제16권8호
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• pp.735-743
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• 2010

A new Fuzzy sliding mode controller is proposed to improve the cornering performance of the four wheel hybrid vehicles. The Fuzzy sliding mode control is applied for the control of rear motor and EHB (Electro-Hydraulic Brake) to improve the cornering performance. The modeling of the automobile is simplified that each of the two wheels is modeled as two degrees of freedom object and the friction coefficient between the wheel and the ground is assumed to be constant. The output of the Fuzzy sliding mode algorithm is the direct yaw moment for the rear wheels, which compensates for the slip angle. Through the simulations using ADAMS and MATLAB Simulink, the cornering performance of the proposed algorithm is compared to the conventional PID to show the superiority of the proposed algorithm. In the simulation experiments, the J-Turn and single lane change are used for each of the Fuzzy sliding mode algorithm and PID controller with the optimal gains which are tuned empirically.

• 한국분무공학회지
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• 제28권3호
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• pp.150-155
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• 2023

Cold-start emissions are given great importance under the Euro-7 emission standard due to their significant impact on overall vehicle emissions. When an engine is started from a cold state, the combustion process is not yet optimized, leading to higher emissions. Hybrid vehicles, in particular, may face additional challenges, as their engine may remain inactive for extended periods, causing their catalysts to cool down and potentially become less effective in reducing emissions. In the present study, the performance of an electric heater was investigated as a means to enhance the catalyst heating during the start-up time. A simulation tool was utilized to develop a model for the gasoline exhaust aftertreatment system. The result indicates that the heater was able to increase the three-way catalyst temperature to 500℃ in 4 s using 20 kW power. In addition, the implementation of a secondary air supply resulted in reduced temperature overshoot and improved conversion efficiencies.