• Title/Summary/Keyword: idle mode

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Filtration Characteristics of Metal Foam Filters for DPF Combined with Electrostatic Precipitation Mechanism (전기집진 기제를 조합시킨 DPF용 금속 폼 필터의 여과 특성)

  • Park, Seok-Joo;Lee, Dong-Geun;Kim, Jin-Hyun;Cho, Gyu-Baek;Kim, Hong-Suk;Jeong, Young-Il
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.2
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    • pp.151-158
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    • 2007
  • Filtration studies, using simulated test nanoparticles or diesel nanoparticles, have been performed about Inconel foam filters for DPF combined with electrostatic precipitation. The simulated test particles were synthesized by laser ablation in the nitrogen atmosphere at the standard condition. The diesel particles were exhausted from the diesel engine driven on the condition of idle or load mode. Filtration efficiency of the metal foam filter is very low because most of particles are penetrated through the large pores of filter. However, the efficiency was considerably improved by applying the electric field to the filter and/or charging the nanoparticles. Nevertheless, the pressure drop of filter hardly increased because the filter-pores were not clogged by deposited particles and kept open.

Thermal Design and Analysis Evaluation of ISG Motor for Hybrid Electric Vehicles considering High-speed Driving Condition (고속 운전조건을 고려한 하이브리드 자동차용 ISG 모터 방열설계 및 해석 평가)

  • Kim, Sung Chul
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.1
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    • pp.59-64
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    • 2014
  • Integrated Starter Generator (ISG) system improves the fuel economy of hybrid electric vehicles by using idle stop and go function, and regenerative braking system. To obtain the high performance and durability of ISG motor under continuously high load condition, the motor needs to properly design the cooling system (cooling fan and cooling structure). In this study, we suggested the enhanced design by modifying the thermal design of the ISG motor and then analyzed the improvement of the cooling performance under high-speed condition and generating mode by CFD simulation. The temperatures at the coil and the magnet of the enhanced model were decreased by about $4^{\circ}C$ and $6^{\circ}C$, respectively, compared to those of the conventional model. Therefore, we verified the cooling performance enhancement of the novel thermal design in the case of core loss increment due to the higher speed condition.

A new MAC protocol to improve a performance in IEEE 802.11 wireless LANs (IEEE 802.11 무선 랜의 성능 향상을 위한 새로운 MAC프로토콜)

  • Hwang, Gyung-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.4
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    • pp.759-764
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    • 2009
  • A new backoff scheme for infrastructure mode in IEEE 802.11 wireless LANs is proposed to improve a performance. Each station generates a unique backoff number using total number of stations, fairness parameter included in beacon frame and an user's ID that is assigned by AP. The station sends a packet after its own backoff number of idle slots, which makes a collision free access among stations within AP's coverage. The proposed method shows better performance in the view of channel utilization and packet delay than an original IEEE 802.11 CSMA/CA backoff scheme.

Dynamic Model Development and Simulation of Crawler Type Excavator (크롤러형 굴삭기의 동역학적 모델 개발 및 시뮬레이션)

  • Kwon, Soon-Ki
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.18 no.6
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    • pp.642-651
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    • 2009
  • The history of excavator design is not long enough which still causes most of the design considerations to be focused on static analysis or simple functional improvement based on static analysis. However, the real forces experiencing on each component of excavator are highly transient and impulsive. Therefore, the prediction and the evaluation of the movement of the excavator by dynamic load in the early design stage through the dynamic transient analysis of the excavator and ensuring of design technique plays an importance role to reduce development-cost, shorten product-deliver, decrease vehicle-weight and optimize the system design. In this paper, Commercial software DADS and ANSYS help to develop the track model of the crawler type excavator, and to evaluate the performance and the dynamic characteristics of excavator with various simulations. For that reason, the track of crawler type excavator is modelled with DADS Track Vehicle Superelement, and the reaction forces on the track rollers were predicted through the driving simulation. Also, the upper frame and cabin vibration characteristics, at the low RPM idle state, were evaluated with engine rigid body modelling. And flexibility body effects were considered to determine the more accurate joint reaction forces and accelerations under the upper frame swing motion.

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Cross-Layer Reduction of Wireless Network Card Idle Time to Optimize Energy Consumption of Pull Thin Client Protocols

  • Simoens, Pieter;Ali, Farhan Azmat;Vankeirsbilck, Bert;Deboosere, Lien;Turck, Filip De;Dhoedt, Bart;Demeester, Piet;Torrea-Duran, Rodolfo;Perre, Liesbet Van der;Dejonghe, Antoine
    • Journal of Communications and Networks
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    • v.14 no.1
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    • pp.75-90
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    • 2012
  • Thin client computing trades local processing for network bandwidth consumption by offloading application logic to remote servers. User input and display updates are exchanged between client and server through a thin client protocol. On wireless devices, the thin client protocol traffic can lead to a significantly higher power consumption of the radio interface. In this article, a cross-layer framework is presented that transitions the wireless network interface card (WNIC) to the energy-conserving sleep mode when no traffic from the server is expected. The approach is validated for different wireless channel conditions, such as path loss and available bandwidth, as well as for different network roundtrip time values. Using this cross-layer algorithm for sample scenario with a remote text editor, and through experiments based on actual user traces, a reduction of the WNIC energy consumption of up to 36.82% is obtained, without degrading the application's reactivity.

Study of the effect of cleaning the intake manifold on common rail diesel engine and exhaust gases (커먼레일 디젤엔진의 흡기 매니폴더 클리닝이 배기가스에 미치는 영향에 관한 연구)

  • Kim, Tae-Jung;Hong, Sung-In
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.10
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    • pp.5912-5918
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    • 2014
  • Owing to highly developed industries and the use of fossil fuels, environmental problems becoming becoming pressing issues globally. Therefore, a study of automobile exhaust is urgently needed. Generally, air is sucked into the engine through the intake manifold. The aims of this study were to reduce the exhaust from used cars and increase the output by removing carbon deposits, which are considered a reason for the increasing exhaust and reduction of output, and the reduction of exhaust, variation of output and stability of idle speed were analyzed. The formation of carbon deposits within the suction manifold was investigated through a test device (KD147). In the intake manifold, the exhaust cleaning effect was confirmed.

A Low-Power Design and Implementation of the Portable Device for Measuring Temperature and Humidity Based On Power Consumption Modeling (소비 전력 모델링에 입각한 휴대용 온습도 측정기의 저전력 설계 및 구현)

  • Lee, Chul-Ho;Hong, Youn-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.2
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    • pp.1027-1035
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    • 2014
  • The most important design factor for portable devices is power consumption. In this paper, in the early design stage of a mobile device which measures temperature and humidity a power consumption model will be proposed and then the overall power consumption will be estimated based on this model. We will verify previously the correctness of such estimated power consumption before implementation of the real device. That is our proposed design methodology based on power consumption model. An improved design method for efficiently reducing the current consumption in the idle mode is also presented. By implementing a real prototype of the mobile device for measuring temperature and humidity, the correctness of our proposed design methodology based on power consumption modeling will be verified.

Experimental Study on the Performance Characteristics of Air Hybrid Engine (Air hybrid 엔진의 구동 특성에 관한 실험적 연구)

  • Lee, Yong-Gyu;Kim, Yong-Rae;Kim, Young-Min;Park, Chul-Woong;Choi, Kyo-Nam;Jeong, Dong-Soo
    • Journal of the Korean Institute of Gas
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    • v.15 no.5
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    • pp.50-56
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    • 2011
  • A preliminary experimental study of new concept air hybrid engine, which stores compressed air in the tank during braking and re-use it to propel vehicle during crusing or acceleration, was carried out in this study. A single cylinder engine was modified to realize the concept of air hybrid engine. Independent variable valve lift system was adopted in one of the exhaust valves to store the compressed air into the air tank during compression period. An air injector module was installed in the place of spark plug, and the stored compressed air was supplied during the expansion period to realize air motoring mode. For air compression mode, the tank with volume of 30 liter could be charged up to more than 13 bar. By utilizing this stored compressed air, motoring work of 0.41 bar of IMEP(Indicated mean effective pressure) at maximum can be generated at the 800rpm conditions, which is higher than the case of normal idle condition by 1.1 bar of IMEP.

Channel Variation Tracking based Effective Preferred BS Selection Scheme of Idle Mode Mobile device for Mobile WiMAX System (Mobile WiMAX시스템에서 채널품질 변동추적을 이용한 유휴모드 이동단말의 효율적인 선호기지국 선택 방안)

  • Lee, Kang-Gyu;Youn, Hee-Yong
    • The KIPS Transactions:PartC
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    • v.17C no.6
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    • pp.471-484
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    • 2010
  • In the wireless communication systems, the power consumption of a mobile device is very important issue due to its battery limitations. Hence most of the standards for wireless networks including a mobile WiMAX system are supporting their own power saving mode in way that a mobile device is able to reduce its energy usage while in the mode. However, those standards just define the arrangement of special time intervals, called a paging listening interval, during which the device needs to receive the paging-related control messages, and they do not specify how to effectively reduce the power in many different network environments. This means the amount of power spent by the device is very dependent on the implementations of individual device-vendors, and undesirable paging loss may happen according to the channel conditions. To reduce unnecessary power usage and the risk of paging loss, this paper proposes the effective frequency/BS selection algorithm applicable to a mobile device operating in the power saving mode, which serves the device with better BS based on the tracking for channel variation. This algorithm consists of the channel estimation phase during each paging listening interval, the tracking phase for the measured results, the frequency reselection phase based on the tracking activity, and the preferred BS reselection phase. Thus the proposed method can improve the paging performance while the device is moving in the network. Also the simulation result shows that the presented scheme is superior to other candidates in energy efficiency due to the channel-adaptive frequency/BS selection.

Ultrasonic Effect on the Extraction of Ash-free coal from Low Rank Coal (저등급 석탄으로부터 초청정석탄의 추출과 초음파의 영향)

  • Lee, Sihyun;Kim, Sangdo;Jeong, Soonkwan;Rhim, Youngjun;Kim, Daehun;Woo, Kwangjae
    • Korean Chemical Engineering Research
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    • v.46 no.3
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    • pp.555-560
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    • 2008
  • Extraction was performed to prepare ash-free coal from low rank coal under the temperature of $200-430^{\circ}C$ and initial pressure of 0.1MPa. Three kinds of coal samples with different rank were used and N-methyl-2-pyrrolidinone(NMP, polar), 1-methyl naphthalene(I-MN, non-polar), Light Cycle Oil(LCO, non-polar) were used as solvents. Results showed that higher extraction yield could be obtained with NMP than with 1-MN and LCO, but the ash concentration shows minimun in the case of 1-MN. Three operation modes were compared, that is, idle, agitation and ultrasonic extraction mode. From the results, it was found that the extraction yield and ash concentration were 70.09% and 1.03% under the agitation mode, 80.7% and 0.76% under the ultrasonic operation mode respectively in the case of NMP used at the temperature of $350^{\circ}C$. Similar results were obtained with 1-MN. Effect of ultrasonic on the extraction was estimated as 15-20% increase in the yields and 26% reduction in the ash concentration.