• 제목/요약/키워드: 내부 EGR

검색결과 13건 처리시간 0.022초

E-EGR Valve 내부 Carbon Deposit 억제를 위한 형상연구 (Design Change of E-EGR Valve to Suppress Carbon Deposit)

  • 이현창;이태곤;박우철
    • 한국산학기술학회논문지
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    • 제11권12호
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    • pp.4685-4690
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    • 2010
  • E-EGR Valve 고장의 원인이 되는 내부 퇴적물 축적을 최소화하기 위한 새로운 Valve 형상을 제안하고자 한다. 전산유체 해석을 통하여 다양한 형상에 대하여 유속과 유량을 관찰하였으며, 밸브 상부에 라운드를 추가한 Valve 디자인 변형을 통하여 유량손실 없이 Valve 내의 유속을 약 10% 향상시킬 수 있었다.

EGR Cooler 내부 형상에 따른 Fouling이 냉각 성능에 미치는 영향 (The Effect of Cooling Efficiency on Fouling by EGR Cooler Internal Shape)

  • 남연우;오광철;이천환;이춘범;이원남
    • 한국자동차공학회논문집
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    • 제19권1호
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    • pp.101-108
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    • 2011
  • Understanding the exhaust gas recirculation (EGR) cooler fouling in diesel engine is important factor in the durability characteristic of a EGR system. We develope a test rig and PM feeder using carbon black to examine the effect of fouling on EGR cooler devices those were consisted of flat and shell & tube type. The EGR cooler fouling process is a complex interaction involving heat exchanger shape, boundary condition, constitutes, chemistry and operating mode. As the soot deposited to EGR cooler, these formed a thin deposit layer that was less heat exchange than the fresh status of tube enclosing the exhaust gas, resulting in lower heat exchange effectiveness in both type coolers. But these deposits caused different results in pressure drop, it is increased in flat type, but decreased in Shell & tube type of EGR cooler. A cause was estimated from a change of the flow structure and a decrease of contact area as the EGR cooler fouling.

체적효율을 고려한 가변밸브 개폐시기의 조정에 의한 실린더내 잔류가스량에 관한 연구 (A Study on the Residual Gas Fraction in Cylinder by the Adjustment of Variable Valve Timing with Volumetric Efficiency)

  • 남정길
    • 한국자동차공학회논문집
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    • 제9권5호
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    • pp.82-88
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    • 2001
  • The EGR is needed fur one of various strategies to reduce NOx emission. But to get the proper EGR rate, the intake and exhaust system become complicated. That is a reason why we consider using the internal EGR system. The internal EGR is a system which reduces NOx by controling the residual gas fraction in cylinder by changing valve timing and valve lift of intake and exhaust. In this paper, characteristics of volumetric efficiency and residual gas fraction in cylinder were investigated for various engine speeds by changing valve timing and valve lift of intake and exhaust in the 4 stroke-cycle diesel engine. Volumetric efficiency and residual gas fraction were calculated by the method of characteristics. As the results, residual gas fraction and volumetric efficiency in cylinder by variable valve timing were visualized.

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SI 엔진 내부의 잔류가스 추정 기법에 관한 연구 (A Study for Predictions of In-Cylinder Residual Gas Fraction in SI Engines)

  • 김성철;이상진;김득상;엄인용;조용석
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 추계학술대회논문집B
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    • pp.903-908
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    • 2001
  • Residual gas acts as a diluent which results in reducing the in-cylinder temperature as well as the flame speed, significantly affecting fuel economy, NOx emissions and combustion stability. Therefore it is important to determine the residual gas fraction as a function of the engine operating parameters accurately. However, the determination of the residual gas fraction is very sophisticated due to the unsteady state of induction and exhaust process. There has been little work toward the development of a generally applicable model for quantitative predictions of residual gas fraction. In this paper, a simple model for calculating the residual gas fraction in SI engines was formulated. The effects of engine operating parameters on the residual gas were also investigated. The amount of fresh air was evaluated through AFR and fuel consumption. After this, from the intake temperature and pressure, the amount of total cylinder-charging gas was estimated. The residual fraction was derived by comparing the total charging and fresh air. This results coincide with measured value very well.

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E-EGR Valve 내부 Carbon Deposit 억제를 위한 형상연구 (Design Change of E-EGR Valve to Suppress Carbon Deposit)

  • 이태곤;이현창;박우철;최신형;이봉섭
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2009년도 추계학술발표논문집
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    • pp.531-533
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    • 2009
  • 본 연구에서는 E-EGR Valve 내에 퇴적물이 쌓여 디젤엔진의 성능을 저하시키는 문제를 해결하기 위하여 CRDI 직분식 4기통 엔진에 장착된 E-EGR 밸브를 대상으로 형상변화에 따른 유동해석을 통하여 퇴적물 축적과 작동불량을 감소 시켜줄 새로운 형상을 제시하고자 하였다.

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코로나 방전-EGR 조합시스템에 의한 디젤기관의 배기 가스 특성 (The Characteristics of Exhaust Gas in Diesel Engine by Corana Discharge-EGR System)

  • 박재윤;정장근;김종석;하현진
    • 조명전기설비학회논문지
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    • 제19권7호
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    • pp.39-44
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    • 2005
  • 고연료 중 대부분이 수소와 탄소의 결합물이다. 연료들은 엔진 내부에서 완전 연소되었을 경우는 수분인 증기와 $CO_2$가 발생된다. 그러나 대개 불완전 연소가 일어나 $NO_x$나 Smoke가 발생되어진다. 그리고 이 물질은 인해에 매우 해로운 물질들이다. 본 논문에서는 EGR과 상용주파수를 이용한 플라즈마 장치를 조합하여 배기가스 유해물질 제거 특성을 연구하였다. $NO_x$의 경우에는 전압과 EGR율이 증가할수록 유해물질 제거 특성이 우수하였고, Smoke의 경우에는 EGR 율이 증가하게 되면 Smoke의 발생율이 증가하였으나 전압이 증가하게 되면 발생율이 감소하였다.

흡배기 밸브시기 동시 변경이 SOHC SI 엔진성능에 미치는 영향 (The Effects of Valve Timing Dual Equal Retard/Advance on Performance in an SOHC SI Engine)

  • 엄인용;이원근
    • 한국자동차공학회논문집
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    • 제11권6호
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    • pp.30-36
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    • 2003
  • Variable valve timing(VVT) mechanisms are used widely for improving fuel consumption and reducing emissions. Most of application, however, are limited in the DOHC engine. Dual equal retard/advance strategy is relatively simple one and can be applied to both SOHC and DOHC engines. In this study, effects of dual equal valve timing retard/advance are investigated to observe the feasibility of VVT system on an SOHC SI engine. The result shows that fuel economy and emissions are improved in the dual retard condition due to increased internal EGR. Some amount of increase in volumetric efficiency can be achieved by advancing valve timing at low speed and by retarding at high speed. In this case, however, full load power is not so much improved as the volumetric efficiency increases because of severe knock. In the dual advance condition, there is no merit in the fuel economy and emission.

디젤엔진 자동차의 EGR 및 공기 제어와 CPF 장치에 관련된 고장사례 고찰 (A Study for Failure Examples of Emission Gas Recirculation and Air Control and Catalyzed Particulate Filter System in Diesel Engine Vehicle)

  • 이일권;국창호;함성훈;이영숙;염광욱;유창배;김성모;임하영;안호철;이정호
    • 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.

플레임트랩에 의한 메탄-공기 예혼합기의 연소특성에 관한 연구 (A Study on Combustion Characteristics of Pre-mixed $CH_4$-air by Flame Trap)

  • 김덕호;이재효;최수진;조규백;정동수
    • 한국자동차공학회논문집
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    • 제13권2호
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    • pp.22-28
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    • 2005
  • Exhaust gas emissions from internal combustion engines are one of the major sources of air pollution. And, it is extremely difficult to increase gasoline engine efficiency and to reduce $NO_X$ and PM(particulate matter) simultaneously in diesel combustion. This paper offers some basic concepts to overcome the above problems. To solve the problems, a recommended technique is CAI(controlled auto-ignition) combustion. In this paper, a flame trap was used to simulate internal EGR(exhaust gas recirculation) effect. An experimental study was carried out to find combustion characteristics using homogeneous premixed gas mixture in the constant volume combustion chamber(CVCC). Flame propagation photos and pressure signals were acquired to verify the flame trap effect. The flame trap creates high speed burned gas jet. It achieves higher flame propagation speed and more stable combustion due to the effect of geometry and burned gas jet.

DME 예혼합 압축 착화 엔진에서 밸브 양정과 개폐시기가 내부 배기가스 재순환과 연소에 미치는 영향 (Effect of Valve Lift and Timing on Internal Exhaust Gas Recirculation and Combustion in DME Homogeneous Charge Compression Ignition Engine)

  • 장진영;배충식
    • 한국자동차공학회논문집
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    • 제17권4호
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    • pp.93-100
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    • 2009
  • Intake/exhaust valve timing and exhaust cam lift were changed to control the internal exhaust gas recirculation (IEGR) and combustion phase of homogeneous charge compression ignition (HCCI) engine. To measure the IEGR rate, in-cylinder gas was sampled during from intake valve close to before ignition start. The lower exhaust cam made shorter valve event than higher exhaust cam and made IEGR increase because of trapping the exhaust gas. IEGR rate was more affected by exhaust valve timing than intake valve timing and increased as exhaust valve timing advanced. In-cylinder pressure was increased near top dead center due to early close of exhaust valve. Ignition timing was more affected by intake valve timing than exhaust valve timing in case of exhaust valve lift 8.4 mm, while ignition timing was affected by both intake and exhaust valve timing in case of exhaust valve 2.5 mm. Burn duration with exhaust valve lift 2.5 mm was longer than other case due to higher IEGR rate. The fuel conversion efficiency with higher exhaust valve lift was higher than that with lower exhaust valve lift. The late exhaust and intake maximum open point (MOP) made the fuel conversion efficiency improve.