• 제목/요약/키워드: Operation Durability

검색결과 294건 처리시간 0.026초

승용차용 세라믹 촉매 담체의 열적 내구성의 실험적 평가 (Experimental Estimation of Thermal Durability in Ceramic Catalyst Supports for Passenger Car)

  • 백석흠;김성용;승삼선;양협;주원식;조석수
    • 대한기계학회논문집A
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    • 제31권12호
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    • pp.1157-1164
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    • 2007
  • Ceramic honeycomb structures have performed successfully as catalyst supports for meeting hydrocarbon, carbon monoxide and nitrous emissions standards for gasoline-powered vehicles. Three-way catalyst converter has to withstand high temperature and thermal stress due to pressure fluctuations and vibrations. Thermal stress constitutes a major portion of the total stress which the ceramic catalyst support experiences in service. In this study, temperature distribution was measured at ceramic catalyst supports. Thermal durability was evaluated by power series dynamic fatigue damage model. Radial temperature gradient was higher than axial temperature gradient. Thermal stresses depended on direction of elastic modulus. Axial stresses are higher than tangential stresses. Tangential and axial stresses remained below thermal fatigue threshold in all engine operation ranges.

MEA의 장기 성능 향상을 위한 VLD 기술 개발 (VLD technique for MEAs performance enhancement)

  • 임상진;김형준;조은애;이상엽;임태훈
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 추계학술대회
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    • pp.494-497
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    • 2006
  • For commercialization of polymer electrolytemembrane fuel cell (PEMFC), durability of membrane electrode assemblies (MEAs) has to be improved. Especially, long-term stability of MEA is one of the most important issues for frequent shut-down and start-up processes of PEMFC. The degradation of MEA could be attributed to chemical attack of hydrogen peroxide radicals that are formed at high cell voltages without any special treatment to remove residual hydrogen from anode gas channel after shut-down of the fuel cell. In this study, we investigated the long-term stability of MEA under different on/off operation conditions. Residential hydrogen gas was removed from the anode flow channel by purging air or nitrogen. Also, a dummy resistance was applied to the fuel cell to exhaust residential hydrogen at the anode. In these cases, MEA showed much more stable durability. Electrochemical characteristics of the fuel cell were measured byrepeating the on/off cycles with the hydrogen removal processes. Also, degradation of MEA components was examined by SEM, TEM and XRD analyses.

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디젤기관의 대체연료 이용에 관한 연구(II) (시동성 및 내구성 문제) (A Study on Alternative Fuel as Fuel Substitutes in a DI Diesel Engine(II) (Startability and Durability))

  • 오영택;정규조;촌산정
    • 오토저널
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    • 제10권6호
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    • pp.48-53
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    • 1988
  • In a previous report, the properties of vegetable oils as diesel fuel substitutes were investigated and the basic load performance of a diesel engine was examined using vegetable oil. The results show that despite of the long term chain hydrocarbon structure and large droplet size due to high viscosity, vegetable oils have good basic performance and exhaust emissions, however they cause serious problems as carbon deposit buildup, they have poor durability, and also poor thermal efficiency. In this paper, the startability and engine durability with long term operation was tested by physical methods for reducing viscosity when vegetable oil was used as compared against diesel fuel. The results obtained in this investigation may be stated as follows; (1) There is no problem in startability when vegetable oil was used as diesel fuel substitutes as far as fuel temperature is higher than 30.deg. C (2) The carbon deposits were most extensive at lower loads and lower engine speeds, and deposit buildup more heavily on the cooler parts of the combustion chamber wall. (3) Blends with 25% diesel fuel and 20v-% ethanol are effective in reducing the carbon deposit buildups. (4) Significant improvement in carbon deposit and piston ring stick can be obtained by heating fuel(200.deg.).

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헬리콥터 착륙장치 복합재 토크링크 피로내구성에 대한 실험적 연구 (An Experimental Study on Fatigue Durability for Composite Torque Link of Helicopter Landing Gear)

  • 권정호;강대환
    • Composites Research
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    • 제23권6호
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    • pp.26-31
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    • 2010
  • 본 연구에서는 새로운 RTM(Resin Transfer Moulding) 제작 공법으로 기존의 금속 재료를 대체 할 헬리콥터 착륙장치 복합재 토크링크의 피로내구성 평가에 대한 절차와 방법론에 대해 기고하였다. 토크링크의 예상 운용 수명을 적용하기 위하여 진보된 확률적 랜덤 처리 기법을 이용한 모사하중 스펙트럼을 산출하고, 기초 물성 실험값을 기반으로 잔여강도 저하를 분석하여 피로내구성 평가를 하였고 실물 피로시험을 수행하여 결과를 비교 검토하였다.

자동 변속기용 ATPS의 내구성 검사 시스템 개발 (Development of a Durability Test System for ATPS Used for Automatic Transmission)

  • 김태규;남형수;신은혜;윤태성
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2007년도 제38회 하계학술대회
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    • pp.1585-1586
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    • 2007
  • In this paper, a system of durability test for ATPS(Automatic Transmission Position Switch), which is used for automatic transmission, has been developed. ATPS is the position sensor for an automatic transmission which transforms the gear changes into the electrical signals and transmits them to TCU(Transmission Control Unit). This system can detect the output signals of the sensor, and also it has been designed to control the position and velocity of a motor to realize the sensor's movement under the running state of a car. And a database system and a GUI system have been developed for the systematic output data management and the convenient interface for users. Also, the operation data and the inspection reference data of a motor can be easily changed in this system, and with some modification the system is also able to used for the durability test of the similar products.

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공동주택 방화문의 내구성능 및 내용연수 제안에 관한 연구 (A Study on the Proposal of Durability and Service Life of Fire Door in apartment house)

  • 권영진;김윤성;진승현
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2022년도 가을 학술논문 발표대회
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    • pp.49-50
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    • 2022
  • There are continuous cases of fire expansion due to fire door problems around the world, including the 2010 Shanghai Apartment Fire, the 2017 Grenfell Tower Fire in England, and the 2020 Ul-san Residential and Commercial Complex Fire. In order to prevent such fire damage, the country has strengthened the performance standards of fire doors, and recently, efforts have been made to ensure the best performance of fire doors by introducing a quality recognition system. Securing the performance of fire doors is a very important aspect. However, there is a concern that old fire doors may not function normally in the event of fire due to natural deterioration, corrosion, and damage during the use process, but countermeasures are insufficient. Therefore, from a management perspective, it is very important to maintain fire doors and secure an appropriate replacement time. Therefore, the purpose of this study is to determine whether the fire door has durability to prevent fire spread in the process of use through operation probability analysis and expert surveys, and to propose an appropriate useful life of the fire door.

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수소전기차 연료전지 수명 향상을 위한 부하 변동 제거 및 스택 내구성 실험 (Load Variation Removal and Stack Durability Experiments to Improve Lifetime of Fuel Cell Stack for Hydrogen Electric Vehicles)

  • 이동원;김범준;이승로
    • 한국수소및신에너지학회논문집
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    • 제35권4호
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    • pp.370-376
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    • 2024
  • Load variations reduce the lifespan of polymer electrolyte fuel cells (PEFCs). To analyze the impact of load variations on durability of PEFCs, two stacks were built and operated continuously for 400 hours, one under load variations and the other under constant current condition with the same energy output. Using the example model provided by Mathworks, we obtained load variation data for the experiments. The performance curves were measured every 100 hours and analyzed by current interruption method and electrochemical impedance spectroscopy. The degradation comparison shows a much larger decrease in performance under the load variation. The activation resistance, electrical resistance, and mass transfer resistance are all found to increase more.

콘크리트궤도 유지보수기준 정립을 위한 연구방향 (Research directions for maintenance criteria in Slab Track)

  • 엄종우;이명석;권진수;김수정
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 춘계학술대회 논문집
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    • pp.979-987
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    • 2011
  • The Ballast Track has been widely applied in traditionally due to low initial cost and abundant elastic property. But the disadvantages of Ballast track are; labor-intensive and costly maintenance, weak in high-speed and heavy axial load, in additionally need wide cross section of tunnel and massive substructure in viaduct. Therefore, recent applications tend to more and more towards slab track such as Gyeungbu high speed rail and existing line. The slab track increased the stability, resistance and durability of track, and save maintenance cost compare to the Ballast Track. But the slab track have weakness of track elongation by sub-ballast differential settlement and that threat safety of train operation. Therefor the slab track need to prevent cracks in concrete ballast for insure the durability of slab track. In this paper, review main items and its expected effects of the slab track maintenance standards that control sub-ballast settlement and concrete ballast cracks.

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다층구조 블래더를 이용한 내압제한장치 개발 (Development of Internal Pressure Maintenance Equipment with Multi-layer Construction Bladder)

  • 백낙곤;유경원;장기원;전필선;하병근;이범철
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2009년도 춘계학술대회 논문집
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    • pp.335-337
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    • 2009
  • 유도무기의 저장기간 동안 주변 온도변화로 인해 생기는 내부 압력변화를 흡수하는 내압제한장치를 개발하였다. 내압제한장치의 주요 구성품인 블래더는 연료 투과를 막고, 내구성을 높이기 위해 다층구조로 개발되었으며, 저장 및 운용 시에 발생할 수 있는 조건에서의 성능확인을 위한 내구성 시험과 환경시험이 수행되었다.

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A Comprehensive Study on Fuel Injector Test Bench for Heavy Duty Engine

  • Das, Shubhra Kanti;Thongchai, Sakda;Lim, Ocktaeck
    • 한국분무공학회지
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    • 제20권3호
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    • pp.195-201
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    • 2015
  • This study discusses a fuel injector test bench containing a mechanical type fuel supply system for heavy duty diesel engine. The main focus of this study was to evaluate the design stability of the test bench, which basically measures the injector durability of a multi-hole heavy duty injector by using pure diesel as a test fuel. In this experiment, diesel spray was controlled by a specially designed control box and all the experiments were carried out to measure e.g. fuel injection pressure and fuel injection quantity to understand the injection status which is interlinked with the stability factor of total test bench design. Also, the durability test was performed to understand the heavy duty operation lastingness of the designed system and the flow rate of the installed distributor pump in the fuel supply system of this studying test bench was compared with LO-1 and LO-2 pump. The results of the above mention tests revealed that the injector test bench design and control system can serve the purpose for heavy duty injector.