• 항공우주기술
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• 제10권1호
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• pp.79-88
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• 2011

발사체의 추진공급계 시스템에서 사용되는 충전/배출 밸브는 지상에서 작동하며 구동가스 공급에 의해 극저온 산화제를 산화제 탱크에 주입 또는 배출하는 역할을 한다. 유즈노이사에서 설계한 산화제 충전/배출 밸브의 설계 자료를 검토하여 수정하였다. 충전/배출 밸브의 제작에 앞서 설계 검증 및 기본적인 작동 특성을 분석하기 위해 AMESim 상용코드를 이용하여 해석 모델을 구성하였다. 밸브 모델을 이용해서 설계 변수에 대해 동특성 해석을 수행하여 밸브 개폐 작동 시간, 작동 성능, 개방 압력을 예상하였다. 본 연구 결과는 한국형 발사체 추진공급계 충전/배출 밸브의 설계 및 선행 연구에 적용할 수 있을 것으로 판단된다.

• 한국가스학회지
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• 제22권2호
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• pp.78-83
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• 2018

이 논문은 디젤엔진 자동차의 EGR 및 공기 제어와 CPF 장치에 관련된 고장사례 연구이다. 첫 번째 사례는 엔진진공펌프 손상으로 인해 엔진오일이 EGR 밸브 내부 다이어프램 손상으로 인해 오일이 흡기로 유입되어 연소실로 들어가 불완전 연소함으로써 배기할 때 매연이 발생된 것으로 확인되었다. 두 번째 사례의 원인은 공기제어 장치인 스로틀 플랩(throttle flap)을 점검하였을 때 스로틀 플랩이 고착되어 흡입공기량 부족에 의해 매연이 발생된 것을 확인하였다. 세 번째 사례는, 배기가스 온도센서의 불량으로 인해 온도를 감지하지 못해 재생기능이 되지 않아 매연이 발생된 것으로 확인되었다. 따라서, 배기가스발생으로 인한 환경오염 문제가 발생하지 않도록 최적의 상태를 유지하도록 관리하여야 한다.

• 한국추진공학회지
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• 제6권4호
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• pp.47-58
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• 2002

압력조절 레귤레이터는 KSR-III 추진제 탱크의 압력 조절용으로 개발하였다. KSR-III 가압 시스템은 가압 탱크, 압력조절용 레귤레이터, 추진제 탱크로 구성된 가장 기본적인 시스템이며 레귤레이터는 헬륨 탱크, 파이로밸브, 헬륨주입밸브와 더불어 가장 핵심적인 부품이다. 1차 시제품으로 기밀, 강도, 기본 성능을 만족하는 상세 설계를 완성하였고 2차 시제품으로 추진기관 종합수류시험을 수행하였다. 2차시험을 통해서 밸브의 용량(Cv)을 늘려야 할 필요성이 나타났다. 3차 시제품에 이를 개선하였으며 추진기관 종합 실추진제 시험과 연소시험을 통해 최종 검증하였다.

• 한국기계기술학회지
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• 제13권4호
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• pp.101-108
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• 2011

On cold start operation of an SI engine, a catalyst shows poor performance before it reaches activation temperature. Therefore, fast warmup of the catalyst is very crucial to reduce harmful emissions. In this study, an appropriate control strategy is investigated to increase exhaust gas temperature through changes of spark timing. Combustion stability is also considered at the same time. Exhaust gas temperature and pressure of combustion chamber are measured to investigate the effects of spark timings on cold start and idle performance. Experiments showed that retarded spark timing promotes the combustion at the end of expansion stroke and increases exhaust gas temperature during cold start.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1520-1523
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• 1997

A rigorous dynamic simulation was performed in binary gas mixture H$_{2}$/CO (70:30 vol.%) to determinate start-up operating conditions of PSA(Pressure Swing Adsorption) processes. The rigorous dynamic model for the PSA process contains an Ergun equation for expressing the pressure drop in a bed, and valve equations to compute the boundary pressure change of the bed. As the result of the continuous dynamic simulation of 100 operating cyles in various initial conditions, the unsteady-state appeared in the early period and the cyclic steady-state came out about 20th cycle in feed condition and vaccum condition, and 30th cycle in pure H$_{2}$ condition. As time goes by valve equations made change the pressure at each end of the bed in ressurization, countercurrunt-depressurization and pressure equalization steps. The H$_{2}$ purity and the recovery is 99.99% and 86.73% respectively, which is slightly higher than the experimental data. Main contributiion of this study includes supplying fundamental technologies of handling combined variables PSA processes by developing rigorous models.

• 동력기계공학회지
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• 제17권6호
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• pp.5-10
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• 2013

Diesel engines have the advantages of good fuel efficiency and low emissions. Therefore, car makers have been developed various kinds of diesel engine management system to clean up emissions while improving fuel efficiency. One of them is the common rail system. In the common rail system, diesel fuel is injected into the combustion chamber at ultra high pressures up to 1,800 bar to ensure more complete combustion for cleaner exhaust gas, and highly precise multiple injection reduces NOx emission, combustion noise and vibration. Generally speaking, common rail system consists of booster pump, high pressure pump, common rail, injectors, control valves, and sensors. The high pressure pump receives low pressure fuel from the booster pump and supply high pressure fuel to injectors through the high pressure common injection rail. Therefore, high pressure pump has an important role in common rail system. In this paper, we have investigated the performance of high pressure pump of common rail system.

• Journal of Mechanical Science and Technology
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• 제19권12호
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• pp.2321-2329
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• 2005

One means of fulfilling $CO_2$ emission legislation is to downsize engines by boosting their power using turbochargers or mechanical superchargers. This reduces fuel consumption by decreasing the engine displacement. When a turbocharger, which is preferable to a mechanical supercharger in terms of fuel efficiency, is used, there is insufficient availability of exhaust gas energy at low engine speeds, resulting in an unfavorable engine response. Therefore, mechanically driven superchargers have increased in popularity due to their quick response to changing speeds in the transient phase. However, since a mechanical supercharger obtains its driving power from the engine, it is difficult to decrease its fuel consumption. This remains a large negative factor for superchargers, despite their excellent dynamic performance. This study aims to develop a power control concept to improve the fuel economy of a mechanical screw supercharger, which could then be used for engine downsizing.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2001년도 추계학술발표회 논문집
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• pp.277-282
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• 2001

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.7-12
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• 1989

This paper describes the design and development of a PWM electronic controller for a high performance Pneumatic Actuation System. The task includes the design of a closed center valve circuit for minimum gas consumption, the selection of optimum values for key parameters in the PWM circuit, and the design of lag-lead compensation circuit. These were carried out through specific experiments using a prototype pneumatic actuation system. The final performance obtained with the actuation system confirmed the successful design of the developed PWM electronic controller.

• 한국자동차공학회논문집
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• 제14권6호
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• pp.9-16
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• 2006

Variable valve timing is one of the attractive ways to control homogeneous charge compression ignition (HCCI) engine. Hot internal residual gas which can be controlled by variable valve timing(VVT) device, makes fuel evaporated easily, and ignition timing advanced. Regular gasoline was used as main fuel and di-methyl ether(DME) was used as ignition promoter in this research. HCCI engine operating range is limited by high combustion peak pressure and engine noise. High combustion pressure can damage the engine during operation. To avoid engine damage, the rich limits have to define using various methods. Peak combustion pressure, rate of cylinder pressure rise was considered to determine rich limit of engine operating range. Knock probability was correlated with the rate of cylinder pressure rise as well as the peak combustion pressure.