• Title/Summary/Keyword: Burned Gas

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Knock Detection Using an Ionization Probe Installed Spark Plug (이온프로브 장착 점화플러그를 이용한 노크발생 판정)

  • 한성주;이용규;민경덕;김응서
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.6
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    • pp.1-8
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    • 2000
  • A new method of knock detection in SI engines, using a change of ion concentration in the combustion chamber, was developed. In order to measure in-cylinder ionization current, ionization probes were installed at spark plug and cylinder head of production engine. It was found that the electric current generated by ionized gas in core burned gas region of knocking cycle is between 2 and 10 times larger than that of normal cycle, because the burned gas temperature which is the dominant parameter of a change of ion concentration increases. However, a change of ionization current in boundary region of burned gas is relatively weak. Hence a change of ion concentration in core burned gas region can be used for knock detection.

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NOx Emissions in Flameless Combustion of Kerosene-Air Mixture Jets Injected into Hot Burned Gas Stream from Combustion Wall

  • Aida, Naoki;Hayashi, Shigeru;Yamada, Hideshi;Kawakami, Tadashige
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.03a
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    • pp.449-452
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    • 2004
  • “Flameless combustion” of lean to ultra lean mixtures, supported by high-temperature burned gas, can resolve the dilemma between complete combustion versus ultra-low NOx emissions in gas turbine combustors. The characteristics of NOx emissions and combustion in “lean-lean” two-stage combustion were investigated for fuel vapor and droplets / air mixture jets injected from the main injection tube that was placed perpendicular to the combustor wall into the primary hot burned gas prepared by combustion of lean mixtures on a perforated flame holder. The present results clearly show that the ultra-low NOx combustion supported by the reaction of lean mixtures well mixed with the hot burned gas from the primary stage is much more advantageous in achieving ultra-low NOx emissions while maintaining high combustion efficiency.

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Prediction of Nitric Oxide Formation Using a Two-Zone Model in a DI Diesel Engine (2영역 모델을 이용한 EGR사용 직접분사식 디젤엔진의 Nox생성예측)

  • Kim, Cheol-Hwan;Lee, Jin-Ho;Chun, Kwang-Min;Lee, Kyo-Seung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.3
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    • pp.390-401
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    • 2000
  • In this study, numerical calculation is carried out to investigate the influence of injection timing, fuel amount, intake $O_2$ concentration, and EGR on Nitric Oxide(NO) formation using a two-zone model in a diesel engine. Results can be summarized as follows. The NO formation is very sensitive to the burned gas temperature, so multi-zone model must be applied to combustion process to predict the burned gas temperature exactly. Since the burned gas temperature increases rapidly during the premixed combustion, most NO is formed within 20 crank angle degrees after ignition. As the injection timing is retarded, the combustion occurs later in the expansion process which causes the decrease of burned gas temperature and, as a result, NO formation decrease. The increase of fuel amount results in the increase of earlier formation of NO in the engine. As the intake $O_2$ concentration increases, the maximum pressure and burned gas temperature increase due to activate combustion. And, [O] mole fraction of equilibrium combustion products also increase. Therefore NO exponentially increases. If exhaust gas is recirculated, the burned gas temperature decreases which results in NO decrease. If exhaust gas is cooled, more NO can be decreased.

A study of turbulent premixed flame structure in a plane shear layer (평면전단층의 난류예혼합 화염의 구조에 관한 실험적 연구)

  • 이재득;최병륜
    • Journal of Advanced Marine Engineering and Technology
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    • v.13 no.4
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    • pp.33-39
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    • 1989
  • A turbulent premixed flames of layer formed between burned hot gas and unburned mixture were investigated by means of schlieren photograph with fluctuations of temperature and ion current. The combustion intensity between burned hot gas and shear layer was higher than the intensity between unburned mixture and shear layer. A wrinkled laminar flame and flamelet were appeared at downstream to exist and distributed reaction zone was at upstream as a result of analyzed probability density functions of temperature fluctuation. The initial combustion intensity of reaction zone of eddy between burned hot gas and shear layer was higher than that of final, flowing downstream, and vice versa between unburned mixture and shear layer.

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

  • Kim, Deok-Ho;Lee, Jai-Hyo;Choi, Su-Jin;Cho, Gyu-Back;Jeong, Dong-Soo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.2
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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.

A Study on the Auto-ignition Combustion Characteristics of CH4-Air Pre-mixtures in Constant Volume Combustion Chamber (정적연소기를 이용한 메탄-공기 예혼합기의 자발화 연소특성에 관한 연구)

  • Lee, Jin-Soo;Lee, Hae-Chul;Cha, Kyung-Ok;Jung, Dong-Soo
    • Journal of ILASS-Korea
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    • v.10 no.2
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    • pp.41-47
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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 NOx 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. internal EGR(exhaust gas recirculation) effect is suggested to realize CAI combustion. An experimental study was carried out to achieve CAI combustion using homogeneous premixed gas mixture in the constant volume combustion chamber(CVCC). A flame trap was used to simulate internal EGR effect and to increase flame propagation speed in the CVCC. Flame propagation photos and pressure signals were acquired to verify internal EGR effect. Flame trap creates high speed burned gas jet. It achieves higher flame propagation speed due to the effect of geometry and burned gas jet.

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Hydrocarbon Speciation in Low Temperature Diesel Combustion (저온 디젤 연소에서 발생하는 탄화수소 종 분석)

  • Han, Man-Bae
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.4
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    • pp.417-422
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    • 2010
  • Low temperature diesel combustion was achieved via a combination of late injection timing ($8.5^{\circ}$ CA BTDC to $0.5^{\circ}$ CA BTDC) and heavy exhaust gas recirculation (37% to 48%) with ultra low sulfur Swedish diesel fuel in a 1.7L common rail direct injection diesel engine. When injection timing is retarded at a certain exhaust gas recirculation rate, the particulate matter and nitrogen oxides decease simultaneously, while the hydrocarbon and carbon monoxide increase. Hydrocarbon speciation by gas chromatography using a flame ionization detector reveals that the ratio of partially burned hydrocarbon, i.e., mainly alkenes increase as the injection timing is retarded and exhaust gas recirculation is increased. The two most abundant hydrocarbon species are ethene which is a representative species of partially burned hydrocarbons, and n-undecane, which is a representative species of unburned hydrocarbons. They may be used as surrogate hydrocarbon species for performing a bench flow reactor test for catalyst development.

Combustion in Methane-Air Pre-Mixture with Water Vapor -Burned Gas Analysis- (물혼합에 의한 메탄-공기 예혼합기의 연소(4) - 연소가스분석-)

  • Kwon, Soon-Ik;Kim, Sang-Jin
    • Journal of the Korean Society of Industry Convergence
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    • v.16 no.1
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    • pp.21-26
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    • 2013
  • Burned gas of methane-air mixtures with water vapor have been analysed to study the exhaust emission using gas-chromatography and computation. The computations were carried out for the gas analysis using premix code of Chemkin program to compare the experimental results. The quantity of water vapor contained were changed 5% and 10% of total mixtures, and equivalence ratio of mixtures between 0.6 and 1.2 were tested under the ambient temperature 323K and 373K. The results showed CO, $CO_2$ decreased and $H_2$ increased by increasing the water contents. The CO increased and $CO_2$ decreased by increasing the ambient temperature. The $CO_2$ shows the maximum product at equivalence ratio 1.0, in otherwise the $CH_4$ produced the minimum values in the same range. The results showed little difference between these two methods.

A study on the burned pattern of plastic wastebasket by reconstruction (플라스틱 휴지통의 연소 재현 실험을 통한 발화지점 축소 방법)

  • An, Seong-Il
    • Journal of Korean Institute of Fire Investigation
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    • v.3 no.1
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    • pp.38-42
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    • 2003
  • There are many origins of fire which are offered by many path, such as cigarette-butt, light of match, playing with fire, arson, and other, in and around wastebasket. Because of above-mentioned thing and the quality of the plastic, it is very difficult to discriminate the difference of burned pattern between in and around wastebasket, between an accidental fire and arson in oder to investigate the point of fire. In this study, the wastebaskets filled up with 2/3 combustibles, and then, in and around wastebasket using the gas lighter by ignitor, and we observe how the fire spread. As a result, if wastebaskets are burned inside the limit 50%, we discriminate the difference of burned pattern between in and around wastebasket. But, if wastebaskets are burned more thant 50%, it is impossible to discriminate the difference of burned pattern between in and around wastebasket.

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The prediction of performance, exhaust emissions and EGR effect of a spark ignition engine by cycle simmulation and experimental method (스파아크 점화기관의 사이클 시뮬레이션과 실험적 방법에 의한 성능, 배출가스, EGR효과의 예측에 관한 연구)

  • 정용일;성낙원
    • Journal of the korean Society of Automotive Engineers
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    • v.8 no.2
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    • pp.31-42
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    • 1986
  • The prediction of performance, exhaust emissions and EGR effect is made by the SI engine cycle simulation. In this simulation several models are employed - two zome, thermodynamic combustion, mass fraction burned, heat transfer, chemical equilibrium, chemical kinetics for NOx, laminar flame speed for ignition delay. The chemical species in burned gas considered are 13 species-CO$_{2}$, CO, $O_{2}$, H$_{2}$O, H$_{2}$,OH, H, O, N$_{2}$, NO$_{2}$, N, Ar - and the cylinder pressure, burned and unburned zone temperature and composition of gas are calculated at each crank angle through the compression, ignition delay, combustion and expansion process. To check the validity of the model, experimental study is done for measuring emissions, combustion pressure and engine output. The predicted values for pressure and emissions show qualitative agreement with the measured data and the EGR effect also shows similar tendency.

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