• Title/Summary/Keyword: 급속 압축 팽창기

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Development of a Rapid Compression Expansion Machine and Compression Ignition Combustion of Homogeneous Premixtures (급속압축팽창기의 제작과 완전 예혼합기의 압축착화 연소실험)

  • 조상현;김기수;임병택
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.2
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    • pp.83-90
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    • 2004
  • A flywheel-driven rapid compression and expansion machine is developed and utilized for experimental study of homogeneous charge compression ignition combustion. Compression ignition of homogeneous charge in IC engines offers possibilities of realizing ultra-lean engine operation with greatly reduced NOx and particulate formation. Fundamental investigations are carried out in order to better understand this ideal engine combustion mechanism. Perfectly premixed propane-air mixtures of various equivalence ratio are compression-ignited in the rapid compression and expansion machine, and the characteristics of the auto-ignition and the following combustion process are analyzed.

A Study on In-cylinder and Combustion Characteristics of GDI Engine using RCEM (급속 압축팽창 장치를 이용한 직접분사식 가솔린 기관의 실린더 내 분무 및 연소특성에 관한 연구)

  • 조규백;정용일
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.7
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    • pp.76-85
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    • 1999
  • GDI(Gasoline Direct Injection( engine technology is well known as a new technology since it can improve fuel consumption and meet future emission regulations. But the GDI has many difficulties to be solved, such as complexity of injection control mode, unburned hydrocarbon, and restricted power. A 2-D shape combustion chamber was adopted to investigate mixture formation and combustion characteristics of GDI engine. Spray and combustion experiments were performed by changing the injection timing. injection pressure an din-cylinder flow in Rapid Compression and Expansion Machine(RCEM).Through the experiments, the detailed characteristics of fuel spray and combustion was analyzed by visualizing the in-cylinder phenomena according to the change of injection condition, and the optimal fuel injection timing and fuel injection pressure were obtained.

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HCCI Combustion of DME in a Rapid Compression and Expansion Machine (급속압축팽창기를 이용한 DME의 HCCI 연소)

  • Sung, Yong-Ha;Jung, Kil-Sung;Choi, Byung-Chul;Lim, Myung-Taeck
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.2
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    • pp.8-14
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    • 2007
  • Compression ignition of homogeneous charges in IC engines indicates possibilities of achieving the high efficiency of DI diesel engines with low level of NOx and particulate emissions. The objectives of this study are to further understand the characteristics of the HCCI(Homogeneous charge compression ignition) combustion and to find ways of extending the rich HCCI operation limit in an engine-like environment. DME fuel is supplied either in the form of premixture with air or directly injected in the combustion chamber of a rapid compression and expansion machine under the conditions of various equivalence ratio and injection timing. The cylinder pressure is measured and the rate of heat release is computed from the measured pressure for the analysis of the combustion characteristics. The experimental data show that the RCEM can operate without knock on mixtures of higher equivalence ratio, when DME is directly injected in the combustion chamber than introduced as a fraction of a perfect or nearly perfect premixture. Very early fuel injection timings usually employed in HCCI operation are seen to have only insignificant effects in control of ignition timing.

A High Expansion Effects of Atkinson Cycle by adopting Variable Intake Valve Closing Timing with Compensated Intake Air-mass and Effective Compression Ratio. (흡입공기량 및 유호압축비 보상시 흡입밸브닫힘시기 변화에 의한 고팽창효과)

  • Jeong, Yang-Joo;Kim, Yun-Young;Lee, Jong-Tai
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1698-1703
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    • 2004
  • To understand the high expansion effects by adopting intake closing time in the cases of compensating intake air-mass and effective compression ratio simultaneously, fundamental study was carried out by using RICEM realizing Atkinson cycle. Intake air-mass and effective compression ratio were compensated by increasing supercharged pressure and geometric compression ratio. The results showed that the increasing rates of expansion ratio and expansion-compression ratio were increased by compensating both a intake air-mass and effective compression ratio the same tendencies were obtained with the increases of compression ratio and cut off ratio It was also found that LIVC has more advantages in expansion ratio and effective work than those of EIVC under above conditions.

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Analysis on the Characteristics of RICEM for Researching Combustion Characteristics of Linear Hydrogen Power System (리니어 수소동력시스템의 연소연구용 급속흡입압축기의 특성 해석)

  • Lee, J.H.;Kim, K.M.;Jeong, D.Y.;Lee, Jong-T.
    • Transactions of the Korean hydrogen and new energy society
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    • v.16 no.1
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    • pp.66-73
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    • 2005
  • Hydrogen linear power system is estimated as the next generation power system which can obtain a performance as same as fuel cell. In order to develop Hydrogen combustion power system with high thermal efficiency, it is very important to understand the basic characteristics of hydrogen combustion and establish combustion stabilization technique of its system. In this study, RICEM(Rapid Intake Compression Expansion Machine) for researching of hydrogen combustion linear power system was manufactured and evaluated, and the basic characteristics of linear RICEM were analyzed.

The Fundamental Study on Generation of High Turbulence at Vicinity of Ignition Timing (점화시기 근방의 고난류 생성을 위한 기초연구)

  • Hong, Jae-Ung;Song, Yeong-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.1
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    • pp.275-283
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    • 1996
  • The turbulence in the engine cylinder is generated by intake pressure and inertia effects during intake stroke, and is generated and decreased by piston compression effect during the compression stroke. The classified needed to generate high turbulence flow at vicinity of ignition timing. Therefore, A single-shot Rapid Intake Compression Expansion Machine (RICEM), which is able to realize the intake, compression, expansion or intake-compression stroke under high piston speed respectively, was manufactured and evaluated in order to find methods to generate high turbulence at around spark timing. It was found that the characteristics of RICEM such as reapperance, leakage, piston displacement with crank angle was corresponding to those of real engine and RICEM simulates not only high temperature and high pressure field but also flow patterns of the actual engine by increasing of pressure in intake line.

A Study on the Backfire and Abnormal Combustion in the Free-piston Hydrogen Fueled Engine (프리피스톤 수소기관의 역화 및 이상연소에 관한 연구)

  • Kim, K.M.;Park, S.W.;Lee, J.H.;Noh, K.C.;Lee, J.T.;Lee, Y.K.
    • Transactions of the Korean hydrogen and new energy society
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    • v.17 no.1
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    • pp.1-7
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    • 2006
  • The free-piston hydrogen fueled engine is estimated as the next generation power system which can obtain high efficiency and low emission, simultaneously. In order to develop the free-piston hydrogen fueled engine, it is necessary to stable the combustion. The engine combustion, backfire and knock phenomenons were studied by using RICEM for researching combustion characteristics of free-piston engine. As the results, backfire occurrence was not observed in the free-piston engine under limited experimental condition. And knocking occurred in case of higher cylinder wall temperature.

A Study on the Combustion Stabilization and Performance Improvement in the Free-piston Hydrogen Fueled Engine (프리피스톤 수소기관의 연소안정화 및 성능향상에 관한 연구)

  • Noh, K.C.;Yoon, J.S.;Kim, K.M.;Park, S.W.;Lee, J.T.
    • Transactions of the Korean hydrogen and new energy society
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    • v.17 no.2
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    • pp.227-233
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    • 2006
  • A free-piston hydrogen fueled engine is considered as one of the next power systems which is able to obtain high efficiency and low emission, simultaneously. In this study, in order to ensure the possibility as the next generation power system, the combustion characteristics and the performance of the free-piston hydrogen fueled engine are analyzed by using the linear RICEM for the change of injection pressure and equivalence ratio. As the results, in-cylinder maximum pressure is shown at injection pressure $P_{inj}$=6bar. Backfire phenomenon is not observed under experimental condition and knock occurs over ${\Phi}=0.8$. The thermal efficiency is the highest at injection pressure, $P_{inj}$=6bar and equivalence ratio, ${\Phi}=0.7$, respectively.