• 한국음향학회지
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• 제41권6호
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• pp.669-679
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• 2022

리튬이온 배터리는 다양한 전자장치에 사용되어왔다. 리튬이온 배터리의 사용이 대중화됨에 따라, 온도, 진동, 쇼크 및 충전 환경과 같은 다양한 요인들이 배터리의 전기화학적 거동 변화에 미치는 영향을 밝히기 위한 연구가 활발히 진행되고 있다. 한편, 지구온난화가 심화되면서 자동차 회사들은 내연기관을 대체하는 파워시스템으로 리튬 이온 배터리를 사용하기 시작했다. 하지만, 배터리는 정적인 시스템을 기반으로 발전되어왔다. 이러한 관점에서, 구조 진동체의 변수와 배터리의 관계를 밝히기 위한 많은 노력이 이루어지고 있다. 본 종설 다이나믹 시스템과 배터리의 관계에 대한 그간의 연구를 요약하고 이를 바탕으로 앞으로의 연구에 대해 전망하고자 한다. 먼저, 전기차의 진동프로파일을 모델링하는 방법에 논하고, 이들이 배터리에 적용되었을 때의 전기화학적 거동에 대하여 다루었다. 이어서 물리적 충격 및 관통, 초음파 등이 배터리에 대해 미치는 영향을 기술하였다. 마지막 단락에서는 전기차와 배터리의 공존 관점에서, 다이내믹 구조물에 특화된 배터리의 디자인, 배터리에 초점을 맞춘 다이내믹 구조물의 관점에서 전기차 샤시 및 배터리에 대한 견해를 기술하였다.

• 신재생에너지
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• 제7권3호
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• pp.59-66
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• 2011

Recently, an UAV using green energy for propulsion has been developed due to exhaustion of fossil fuel. This aircraft runs on electric motors rather than internal combustion engines, with electricity coming from fuel cells, solar cells, ultracapacitors, and/or batteries. Especially solar cells are installed in HALE UAV and flight tests are performed in the stratosphere. Although the solar powered UAV has the advantage of zero emission, its energy conversion efficiency is low and operation time is limited. Therefore, the solar powered UAV has been designed to operate with the secondary battery obtaining flexibility of energy management. In this study, we suggest the new operational concept of the solar powered UAV using directed-energy rayed from the surface of earth to UAV. An UAV is able to secure additional power through attaching solar cell to the lower surface of elevator. As a result, the additional energy supplied by directed-energy can improve the energy management and operational flexibility of the solar powered UAV.

• 한국수소및신에너지학회논문집
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• 제35권2호
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• pp.230-239
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• 2024

Efforts are being made to replace ship diesel engines with electric propulsion motors in response to emission regulations. In particular, in the case of short-range small ships, research is being conducted to replace polymer electrolyte membrane fuel cells (PEMFC) with power sources. However, PEMFC has problems such as slow dynamic response characteristics and reduced durability at high temperatures. To solve this problem, a high-precision ship model was developed with power distribution and thermal management strategies applied, and through this, the required power, heat, and power characteristics of the propulsion system according to the ship's speed profile were analyzed.

• International Journal of Automotive Technology
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• 제4권1호
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• pp.41-45
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• 2003

The 42V Mild Hybrid System has been released into market by Toyota for the first time in the world in 2001. The set-up employs an inverter unit to control the motor/generator (MG) electronically. The driving system called such as Toyota Mild Hybrid System (TMHS) has additional new functions to conventional internal combustion engines. When stopping vehicle, the engine stops promptly. When starting vehicle, by releasing the brake pedal MG starts the vehicle at the same time (EV-driving mode). When stepping on the accelerator pedal, or after a given period of time the engine firing occurs and the engine-driving mode starts. When running by motor, the power is supplied to the motor from 36V battery through the inverter. High outputs and instant responses are required for Inverter. At the same time, the compact volume is required to fit into the limited space of the engine room. The compact size and high output are also required to Power Capacitor used for this inverter. The power capacitors has been newly developed, shaped in "flat" type, suitably for the inverter. The points of developments on inverter and power capacitor are described in this paper.his paper.

• 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..

• 한국분무공학회지
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• 제11권4호
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• pp.228-233
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• 2006

There are two types of electric controlled fuel injection system in the gasoline engines of common vehicles. One is fuel return system and the other is fuel returnless system according to the methods of controlling injection pressures. It is important to understand the characteristics of these system in loaming and studying of engine, but it is very difficult without a special equipment in reality. The purpose of this paper is to develop the emulation system that can be compensated with the amount of injection fuel according to various driving conditions, battery voltage, cooling water temperature, and engine speed, may be appeared in real driving, and especially can analyze the difference between the electric signal controlling the amount of injection fuel and its result, and nullity injection duration. With the developed system, we can conveniently set various and completed driving condition and so can acquire the useful information such as non-uniformity rate and mass of injection fuel using waveform analysis and measurement modules. It must be a very useful and sophisticated system to instruct and learn the features and operating states of injection system, and to study f3r improving the performance of it.

• 에너지공학
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• 제25권4호
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• pp.170-175
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• 2016

현재 자동차의 주요 동력원은 내연기관이 가장 많은 비중을 차지하고 있다. 내연기관 자동차로 인한 환경문제를 해결하기 위한 친환경 자동차로는 하이브리드 자동차, 전기 자동차 및 공기 엔진 자동차 등을 들 수 있다. 배터리를 이용하는 하이브리드 차나 순수 전기차 등도 아직은 크지 않으나 점차 많은 비중을 차지하여 나가고 있다. 전기모터를 사용하는 전기차에 비해 압축공기를 이용하는 공기 엔진 자동차는 아직은 연구개발이 거의 이루어지지 않은 상태이다. 본 논문에서는 스크롤 팽창기를 적용하는 새로운 압축공기 엔진을 소개하고, 이 엔진을 장착한 자동차의 주행거리 가능 거리를 이론적으로 산출하였다.

• 전기학회논문지
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• 제64권12호
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• pp.1666-1672
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• 2015

Small islands are quite adequate places where microgrid system with renewable sources can replace diesel engines as operation costs of diesel engine in most small islands are very high. To get the large amount of renewable energy, the microgrid system has very large capacity of renewable sources. The system with large capacity of renewable sources can meet the case when supplied energy is greater than the load and the fluctuation of source output is very large. The battery energy storage system can be a solution to stabilize the system with large capacity of renewable sources. In this case, BESS can be utilized as a master source for the synchronous operation of all sources including diesel engine, wind turbine and PV. The diesel generators can be used as a backup in case the BESS SOC goes below a certain level. In this paper, we suggest a novel unit commitment of diesel generators and operation schedule of pump for water supply service with the information of wind forecast, PV forecast, and load forecast. The proposed methods has been implemented and tested at the test bed in Gasa-Island.

• 한국염색가공학회지
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• 제32권1호
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• pp.65-71
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• 2020

Electrical energy is used for heating and cooling because electric cars do not have engines and cooling water. The downside is that when the heating and cooling system is applied to electric vehicles, about 40 percent of the energy is spent on heating and cooling, which is less efficient in winter. This has increased demand for electric vehicle battery efficiency. In this study, the condensation and dispersion of carbon nanotubes were controlled, and carbon fibers and composite slurry were manufactured without binders to manufacture paper. Manufactured by content showed the highest heat generation characteristic at 143℃ with a carbon fiber content ratio of 20wt% and confirmed that the heat temperature rises with increasing pressure. The plane heaters made through this study can be applied to a variety of products other than electric vehicles because they can be simplified by process and high temperature.

• International Journal of Automotive Technology
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• 제8권5호
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• pp.555-562
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• 2007

The Variable Valve Timing(VVT) system for high performance is a key technology used in newly developed engines. The system realizes higher torque, better fuel economy, and lower emissions by allowing an additional degree of freedom in valve timing during engine operation. In this study, a model-based control method is proposed to enable a fast and precise VVT control system that is robust with respect to manufacturing tolerances and aging. The VVT system is modeled by a third-order nonlinear state equation intended to account for nonlinearities of the system. Based on the model, a controller is designed for position control of the VVT system. The sliding mode theory is applied to controller design to overcome model uncertainties and unknown disturbances. The experimental results suggest that the proposed sliding mode controller is capable of improving tracking performance. In addition, the sliding mode controller is robust to battery voltage disturbance.