• Title, Summary, Keyword: Electric vehicle

Search Result 1,910, Processing Time 0.044 seconds

Stakeholder Oriented Economical Efficiency Analysis on the Scenario to Implement Smart Transportation Services (지능형 운송 서비스 구축 시나리오에 대한 이해관계자 중심 경제성 분석)

  • Shin, KwangSup;Moon, Yongma;Hur, Wonchang;Kim, Woo Je
    • Journal of the Korea Society for Simulation
    • /
    • v.24 no.1
    • /
    • pp.35-43
    • /
    • 2015
  • This research proposed a new method to evaluate the objective validity to launch smart transportation services that various stakeholders are complicatedly inter-connected. First of all, we have designed the fundamental business model to form the smart transportation services and defined the stakeholders taking part in the services. Also, the criteria to evaluate the economical validity has been proposed based on the relationship among stakeholders. Especially, in the case EV drivers and charging service providers, the economical validity depends on the scale of spreading. Therefore, we have compared the two extreme scenarios, the poor and stable level of EV spreading. According to the result, it may be said that EV drivers and charging service providers cannot be guaranteed the economical validity due to the burden of initial investment. On the contrary to this, suppliers of EV and charging gears may secure more than a certain level of profit. In addition, the government may have great profit due to reducing the CO2 emission and cost for importing energy sources. Therefore, it is needed to enhance the level of supporting EV drivers and charging service providers at the first stage. Also, the impact of the ratio of EV and charging service stations on the economical validity of smart transportation should be further investigated.

Rotordynamic Performance Measurements and Predictions of a FCEV Air Compressor Supported on Gas Foil Bearings (가스 포일 베어링으로 지지되는 연료전지 전기자동차용 공기압축기의 회전체동역학적 성능 측정 및 예측)

  • Hwang, Sung Ho;Moon, Chang Gook;Kim, Tae Ho;Lee, Jongsung;Cho, Kyung Seok;Ha, Kyoung-Ku;Lee, Chang Ha
    • Tribology and Lubricants
    • /
    • v.35 no.1
    • /
    • pp.44-51
    • /
    • 2019
  • The paper presents the rotordynamic performance measurements and model predictions of a fuel cell electric vehicle (FCEV) air compressor supported on gas foil bearings (GFBs). The rotor has an impeller on one end and a thrust runner on the other end. The front (impeller side) and rear (thrust side) gas foil journal bearings (GFJBs) are located between the impeller and thrust runner to support the radial loads, and a pair of gas foil thrust bearings are located on both sides of the thrust runner to support the axial loads. The test GFJBs have a partial arc shim foil installed between the top foil and bump strip layers to enhance hydrodynamic pressure generation. During the rotordynamic performance tests, two sets of orthogonally installed eddy-current displacement sensors measure the rotor radial motions at the rotor impeller and thrust ends. A series of speed-up and coast-down tests to 100k rpm demonstrates the dominant synchronous (1X) rotor responses to imbalance masses without noticeable subsynchronous motions, which indicates a rotordynamically stable rotor-GFB system. Finite element analysis of the rotor determines the rotor free-free (bending) natural modes and frequencies well beyond the maximum rotating frequency. The predicted damped natural frequencies and damping ratios of the rotor-GFB system reveal rotordynamic stability over the speeds of interest. The imbalance response predictions show that the predicted critical speeds and rotor amplitudes strongly agree with the test measurements, thus validating the developed rotordynamic model.

Effect of Hydrogen Purge Mode on the Polymer Electrolyte Membrane Fuel Cell (PEMFC) Performance under Dead-ended Anode Operation (양극 닫힌계 작동에서 수소 배출 방법에 의한 고분자전해질 연료전지 성능 영향)

  • Kim, Junseob;Kim, Junbom
    • Applied Chemistry for Engineering
    • /
    • v.30 no.6
    • /
    • pp.687-693
    • /
    • 2019
  • As the hydrogen fuel cell market is expanded starting from hydrogen electric vehicle and power generation field, the demand for fuel cells and hydrogen increases recently. Therefore, research works on fuel cell durability and fuel efficiency are required in order to activate the fuel cell market and commercialization. A dead-ended anode system was used in this study to optimize the fuel cell performance and fuel efficiency. The effect of purge condition according to the applied current and hydrogen supply pressure on the fuel cell performance were evaluated. In addition, the influence of water back diffusion on the different electrolyte membrane thickness was analyzed. The accumulated water was purged with a solenoid valve in the case of 3% voltage decrease in the dead-ended anode system. The experiment was performed with the hydrogen supply pressure of 0.1~0.5 bar and purge duration of 0.1~1 second. A maximum fuel efficiency of 98.9% was achieved under the purge duration of 0.1 s and hydrogen supply pressure of 0.1 bar with a NR 211 (25.4 um) membrane. However, the fuel cell performance decreased in a long-term operation due to some frequent flooding. The fuel efficiency and purge interval increased due to decreased back diffusion rates of the water and nitrogen with a NR 212 (50.8 um) membrane.

FEA(Finite Element Analysis) Study for Electronic Hydrogen Regulator of Confidentiality Improvement (전자식 수소레귤레이터 기밀성 향상을 위한 FEA 연구)

  • Son, Won-Sik;Song, Jae-Wook;Jeon, Wan-Jae;Kim, Seung-Mo
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.20 no.9
    • /
    • pp.175-181
    • /
    • 2019
  • In the case of a conventional single stage decompression regulator used for large depressurization in the hydrogen fuel cell system of a fuel cell electric vehicle (FCEV), problems can arise, such as pulsation, slow response, hydrogen brittleness, leakage, high weight, and high cost due to high decompression. Most of these problems can be overcome easily using two decompression mechanisms (two-stage structures). In addition, a wide outlet-pressure control range can be secured if an electronic solenoid is applied to the second decompression. Accordingly, it is necessary to improve the precision of the outlet pressure of a two-stage pressure-reducing regulator and develop techniques, such as leakage prevention, durability, light weight, and price reduction. Therefore, to improve the outlet pressure accuracy and prevent leakage, the structural part before and after decompression to improve the air tightness were divided and the analysis was carried out assuming that the valve part was closed (open ratio: 0%) after each initial internal pressure application.

A Review on 3D Structure Formation, Analysis and Performance Prediction Technique for All-solid-state Electrode and Battery (3차원 전고체 전극 구조체 형성, 분석 및 성능 예측 기술 동향)

  • Park, Joonam;Jin, Dahee;Kim, Dohwan;Bae, Kyung Taek;Lee, Kang Taek;Lee, Yong Min
    • Journal of the Korean Electrochemical Society
    • /
    • v.22 no.4
    • /
    • pp.139-147
    • /
    • 2019
  • Lithium-ion battery (LiB) with high energy density and efficiency has been utilized for the electric vehicle (EV) and energy storage system (ESS) as well as portable devices. However, as explosion accidents have frequently happened till lately, all-solid-state lithium secondary battery (ALSB) began to get in a spotlight because it can secure a very high safety and energy density by substituting flammable organic liquid electrolyte to nonflammable inorganic solid electrolyte. In spite of ALSB's certain merits, it has shown much poorer performance of cells than one of LiB due to some challenges, which have been small or never dealt with in the LiB system. Hence, although plenty of studies made progress to solve them, an approach about design of all-solid-state electrode (ASSE) has been limited on account of difficulty of ALSB's experiments. That is why the virtual 3D structure of an all-solid-state electrode has to be built and used for the prediction of cell performance. In this study, we elucidate how to form the 3D ASSE structure and what to be needed for the simulation of characteristics on ALSB. Furthermore, the ultimate orientation of 3D modeling and simulation for the study of ALSB are briefly suggested.

Technology Trend Analysis in the Automotive Semiconductor Industry using Topic Model and Patent Analysis (토픽모델 및 특허분석을 통한 차량용 반도체 기술 추세 분석)

  • Nam, Daekyeong;Choi, Gyunghyun
    • Journal of Korea Technology Innovation Society
    • /
    • v.21 no.3
    • /
    • pp.1155-1178
    • /
    • 2018
  • Future automobiles are evolving into movable living spaces capable of eco-friendly autonomous driving. The role of electrically processing, controlling, and commanding various information in the vehicle is essential. It is expected that the automotive semiconductor will play a key role in the future automobile such as self-driving and eco-friendly automobile. In order to foster the automotive semiconductor industry, it is necessary to grasp technology trends and to acquire technology and quality that reflects the requirements in advance, thereby achieving technological innovation with industrial competitiveness. However, there is a lack of systematic analysis of technology trends to date. In this study, we analyzed the technology trends of automotive semiconductors using patent analysis and topic model, and confirmed technologies such as electric cars, driving assistance, and digital manufacturing. The technology trends showed that element technology and technical characteristics change according to technology convergence, market needs, and government regulations. Through this research, it is expected that it will help to make R&D policy for automotive semiconductor industry and to make decision for industrial technology strategy establishment. In addition, it is expected that it will be used effectively in detail research direction and patent strategy establishment by providing detailed classification of technology and trend analysis result of technology.

Encoder Type Semantic Segmentation Algorithm Using Multi-scale Learning Type for Road Surface Damage Recognition (도로 노면 파손 인식을 위한 Multi-scale 학습 방식의 암호화 형식 의미론적 분할 알고리즘)

  • Shim, Seungbo;Song, Young Eun
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • v.19 no.2
    • /
    • pp.89-103
    • /
    • 2020
  • As we face an aging society, the demand for personal mobility for disabled and aged people is increasing. In fact, as of 2017, the number of electric wheelchair in the country continues to increase to 90,000. However, people with disabilities and seniors are more likely to have accidents while driving, because their judgment and coordination are inferior to normal people. One of the causes of the accident is the interference of personal vehicle steering control due to unbalanced road surface conditions. In this paper, we introduce a encoder type semantic segmentation algorithm that can recognize road conditions at high speed to prevent such accidents. To this end, more than 1,500 training data and 150 test data including road surface damage were newly secured. With the data, we proposed a deep neural network composed of encoder stages, unlike the Auto-encoding type consisting of encoder and decoder stages. Compared to the conventional method, this deep neural network has a 4.45% increase in mean accuracy, a 59.2% decrease in parameters, and an 11.9% increase in computation speed. It is expected that safe personal transportation will be come soon by utilizing such high speed algorithm.

Mission Analysis Involving Hall Thruster for On-Orbit Servicing (궤도상 유지보수를 위한 홀추력기 임무해석)

  • Kwon, Kybeom
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.48 no.10
    • /
    • pp.791-799
    • /
    • 2020
  • Launched in October 2019, Northrop Grumman's MEV-1 was the world's first unmanned mission demonstrating the practical feasibility of on-orbit servicing. Although the concept of on-orbit servicing was proposed several decades ago, it has been developed to various mission concepts providing services such as orbit change, station keeping, propellant and equipment supply, upgrade, repair, on-orbit assembly and production, and space debris removal. The historical success of MEV-1 is expected to expand the market of on-orbit servicing for government agencies and commercial sectors worldwide. The on-orbit servicing essentially requires the utilization of a highly propellant efficient electric propulsion system due to the nature of the mission. In this study, the space mission analysis for a simple on-orbit mission involving Hall thruster is conducted, which is life extension mission for geostationary orbit satellites. In order to analyze the mission, design space exploration for various Hall thruster design variable combinations is performed. The values of design variables and operational parameters of Hall thruster suitable for the mission are proposed through design space analysis and optimization, and mission performance is derived. In addition, the direction of further improvement for the current on-orbit mission analysis process and space mission analysis involving Hall thruster is reviewed.

The Mechanical Properties of SMA Concrete Mixture Using Steel Slag Aggregate (제철 슬래그 골재를 이용한 SMA 혼합물의 역학적 특성)

  • Kim, Hyeok-Jung;Na, Il-Ho
    • Journal of the Korean Recycled Construction Resources Institute
    • /
    • v.9 no.1
    • /
    • pp.109-116
    • /
    • 2021
  • In order to replace mineral aggregate used as road pavement materials with steel slag aggregate, this present study evaluated mechanical properties of SMA Concrete mixtures using steel slag aggregate as oxidized slag from electric furnace in iron works. The variables of this experiment are the aggregate type of mineral and steel slag and the sieve sized of 10mm and 13mm. The physical properties inclu ding the specific gravity and absorption rate etc. of the slag aggregate mixtu res satisfied the KS standard as asphalt mixtu re. As a resu lt of evalu ating the mechanical properties of the asphalt mixtures, the optimum asphalt content of the slag aggregate mixtures were lower than that of the mineral aggregate mixtures, but other quality standards were all satisfied. In the deformation strength evaluation, the slag aggregate mixtures were measu red slightly higher than that of the mineral aggregate mixtu res, and the dynamic stability test satisfied the 2,000pass/mm standard value in all specimens. And, the moduli of resilient of the slag aggregate mixtures showed an improved value compared with the mineral aggregate mixtures. Therefore, as the resilient rate of the slag aggregate mixtures improved, it is speculated that there will be an effect of improving public performance according to the repeated traffic load of the vehicle.

Prediction of field failure rate using data mining in the Automotive semiconductor (데이터 마이닝 기법을 이용한 차량용 반도체의 불량률 예측 연구)

  • Yun, Gyungsik;Jung, Hee-Won;Park, Seungbum
    • Journal of Technology Innovation
    • /
    • v.26 no.3
    • /
    • pp.37-68
    • /
    • 2018
  • Since the 20th century, automobiles, which are the most common means of transportation, have been evolving as the use of electronic control devices and automotive semiconductors increases dramatically. Automotive semiconductors are a key component in automotive electronic control devices and are used to provide stability, efficiency of fuel use, and stability of operation to consumers. For example, automotive semiconductors include engines control, technologies for managing electric motors, transmission control units, hybrid vehicle control, start/stop systems, electronic motor control, automotive radar and LIDAR, smart head lamps, head-up displays, lane keeping systems. As such, semiconductors are being applied to almost all electronic control devices that make up an automobile, and they are creating more effects than simply combining mechanical devices. Since automotive semiconductors have a high data rate basically, a microprocessor unit is being used instead of a micro control unit. For example, semiconductors based on ARM processors are being used in telematics, audio/video multi-medias and navigation. Automotive semiconductors require characteristics such as high reliability, durability and long-term supply, considering the period of use of the automobile for more than 10 years. The reliability of automotive semiconductors is directly linked to the safety of automobiles. The semiconductor industry uses JEDEC and AEC standards to evaluate the reliability of automotive semiconductors. In addition, the life expectancy of the product is estimated at the early stage of development and at the early stage of mass production by using the reliability test method and results that are presented as standard in the automobile industry. However, there are limitations in predicting the failure rate caused by various parameters such as customer's various conditions of use and usage time. To overcome these limitations, much research has been done in academia and industry. Among them, researches using data mining techniques have been carried out in many semiconductor fields, but application and research on automotive semiconductors have not yet been studied. In this regard, this study investigates the relationship between data generated during semiconductor assembly and package test process by using data mining technique, and uses data mining technique suitable for predicting potential failure rate using customer bad data.