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  • Title/Summary/Keyword: Fuel pressure control

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Analysis of Hydraulic Characteristics of Two Solenoid-driven Injectors for CRDi System (2개 솔레노이드 구동방식별 CRDi용 인젝터의 유압 동특성 해석)

  • Lee, Jin-Wook;Lee, Jung-Hyup;Kim, Min-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.6
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    • pp.140-147
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    • 2011
  • The injection nozzle of an electro-hydraulic injector for the common rail Diesel fuel injection system is being opened and closed by movement of a injector's needle which is balanced by pressure at the nozzle seat and at the needle control chamber, at the opposite end of the needle. In this study, the slenoid actuator was considered as a prime movers in high pressure Diesel injector. Namely a solenoid-driven Diesel injector with different driving current types, as a general method driven by solenoid coil energy, has been applied with a purpose to develop the analysis model of the solenoid actuator to predict the dynamics characteristics of the hydraulic component (injector) by using the AMESim code. Aimed at simulating the hydraulic behavior of the solenoid-driven injector, the circuit model has been developed as a unified approach to mechanical modeling in this study. As this analytic results, we know the suction force and first order time lag for driving force can be endowed in solenoid-driven injector in controlling the injection rate. Also it can predict that the input current wave exerted on solenoid coil is the dominant factor which affects on the initial needle behavior of solenoid-driven injector than the hydraulic force generated by the constant injection pressure.

Comparison of Environmental Conditions and Insulation Effect between Air Inflated and Conventional Double Layer Greenhouse (공기주입 및 관행 이중피복온실의 재배환경 및 단열성능 비교)

  • Jayasekara, Shanika N.;Na, Wook H.;Owolabi, Abdulhameed B.;Lee, Jong W.;Rasheed, Adnan;Kim, Hyeon T.;Lee, Hyun W.
    • Journal of Bio-Environment Control
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    • v.27 no.1
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    • pp.46-53
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    • 2018
  • This study was conducted to determine which greenhouse provided good environmental conditions for strawberry production, and performed better at conserving energy. Temperature, RH, VPD, CO2, solar radiation, yield, and fuel consumption were the parameters analyzed. The temperatures of both greenhouses were well controlled in order to provide optimal day and night temperatures for strawberry production. The air inflated double layer greenhouse had higher RH values (more than 90% at night), which led to higher disease occurrence, in comparison to the conventional double layer greenhouse. Furthermore, the air inflated double layer greenhouse had lower VPD values than the conventional double layer greenhouse. Therefore, better RH and VPD were observed in the conventional double layer greenhouse. Higher CO2 concentration was observed in the air inflated double layer greenhouse while the conventional double layer greenhouse ventilated better than the air inflated greenhouse, because of its side ventilators. Moreover, higher solar radiation in the conventional double layer greenhouse resulted in higher yield, in comparison to the air inflated double layer greenhouse. Thus, we can conclude that the conventional double layer greenhouse provided a better environment for crop growth, in comparison to the air inflated double layer greenhouse. Regarding fuel consumption, the air inflated double layer greenhouse had lower fuel consumption than the conventional double layer greenhouse. Therefore, from an energy consumption point of view, we can conclude that the air inflated double layer greenhouse performed better than the conventional double layer greenhouse.

An experimental study of the deposition of inorganic salts from seeded combustion gases by optical methods (광학적 방법에 의한 연소 개스에 포함된 알칼리 금속 염의 부착에 관한 실험적 연구)

  • 김상수;우성구
    • Journal of the korean Society of Automotive Engineers
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    • v.7 no.2
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    • pp.55-63
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    • 1985
  • This study is focused on deposition process leading to inefficiency and hot corrosion in fossil fuel-fired furnaces and engines. An improved understanding of the coupled thermodynamics, kinetics, and transport processes governing the deposition rate of inorganic oxides and salts from hot gases containing these compounds can suggest more efficient test strategies and control measures. Accordingly, an optical re-evaporation method for accurately measuring the growth rate of deposits under laboratory burner conditions has been developed. To demonstrate the technique and provide data suitable for theoretical model development, a deliberately simple chemical system and target geometry are used. Potassium sulfate(K2SO4)is introduced into a premixed propane-air flat flame at atmospheric pressure. The growth rate of K2SO4 on an electrically heated Pt ribbon is measured by re-evaporation technique.

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Effect on Transient Performance of Driver's Acceleration Type in MPI Gasoline Engine (운전자의 가속타입이 MPI 가솔린엔진의 과도성능에 미치는 영향)

  • 곽지현;전충환;장영준
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.1
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    • pp.75-81
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    • 2000
  • To provide the appropriate direction for development of transient control in a gasoline engine, transient performance analysis and evalution under four accelerating types based on typical driver's acceleration type were implemented by experimental study. In order to evaluate the characteristics of transient performance quanititatively, the concept and method by transient response specifications were introduced. Several performance parameters in terms of engine speed(RPM), manifold absolute pressure(MAP), fuel injection duration(\DeltatInj) and air excess ratio(λ) were emasured simultaneously during the four types of the throttle valve opening with the step motor controlled by PC. The result showed that transient response specifications in terms of delay time, rising time and settling time characterized the transient performance for four acceleration types quantitatively. Intensified acceleration type was most economical and linear acceleration type revealed the best emission performance.

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Solar Sails: Technology And Demonstration Status

  • Johnson, Les;Young, Roy;Barnes, Nathan;Friedman, Louis;Lappas, Vaios;McInnes, Colin
    • International Journal of Aeronautical and Space Sciences
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    • v.13 no.4
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    • pp.421-427
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    • 2012
  • Solar Sail propulsion has been validated in space (IKAROS, 2010) and soon several more solar-sail propelled spacecraft will be flown. Using sunlight for spacecraft propulsion is not a new idea. First proposed by Frederick Tsander and Konstantin Tsiolkovsky in the 1920's, NASA's Echo 1 balloon, launched in 1960, was the first spacecraft for which the effects of solar photon pressure were measured. Solar sails reflect sunlight to achieve thrust, thus eliminating the need for costly and often very-heavy fuel. Such "propellantless" propulsion will enable whole new classes of space science and exploration missions previously not considered possible due to the propulsive-intense maneuvers and operations required.

Measurement and Prediction of Autoignition Temperature(AIT) of Flammable Substances - Methanol and Ethanol - (가연성물질의 자연발화온도 측정 및 예측 - 메탄올과 에탄올 -)

  • Ha, Dong-Myeong
    • Journal of the Korean Society of Safety
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    • v.19 no.2
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    • pp.54-60
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    • 2004
  • Flammable substances are frequently used chemical industry processes. An accurate knowledge of the ALTs(Autoignition Temperatures) is important in developing appropriate prevention and control measures in industrial fire protection. The AITs describe the minimum temperature to which a substance must be heated, without the application of a flame or spark, which will cause that substance to ignite. The AITs are dependent upon many factors, namely initial temperature, pressure, volume, fuel/air stoichiometry, catalyst material, concentration of vapor, ignition delay. This study measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for methanol and ethanol. The A.A.P.E.(Average Absolute Percent Error) and the A.A.D.(Average Absolute Deviation) of the experimental and the calculated delay times by the AITs for methanol were 14.59 and 1.76 respectively. Also the A.A.P.E. and the A.A.D. of the experimental and the calculated delay times by the ATIs for ethanol were 8.33 and 0.88.

Measurement of Autoignition Temperature of o-Xylene+n-pentanol System (오토자일렌과 노말펜탄올 계의 최소자연발화온도 측정)

  • Ha, Dong-Myeong;Lee, Sung-Jin
    • Journal of the Korean Society of Safety
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    • v.21 no.4 s.76
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    • pp.66-72
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    • 2006
  • An accurate knowledge of the AITs(autoignition temperatures) is important in developing appropriate prevention and control measures in industrial fire protection. The measurement of AITs are dependent upon many factors, namely initial temperature, pressure, vessel size, fuel/air stoichiometry, catalyst, concentration of vapor, ignition delay time. The values of the AITs used process safety are normally the lowest reported, to provide the greatest margin of sefety. This study measured the AITs of o-xylene+n-pentanol system from ignition delay time by using ASTM E659-78 apparatus. The experimental AITs of o-xylene and n-pentanol were 480Cand285C, respectively. The experiment AITs of o-xylene+n-pentanol system were a good agreement with the calculated AITs by the proposed equations with a few A.A.D.(average absolute deviation).

Study on the Improvement of Output Fluctuation from Generator Driven by Large Size-Low Speed Diesel Engine (대형저속 디젤엔진 구동 발전기의 출력변동 개선에 관한 연구)

  • 김영주;전효중;이돈출;이충기
    • Journal of Advanced Marine Engineering and Technology
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    • v.16 no.5
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    • pp.6-16
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    • 1992
  • Since world-wide oil shock on 1970s, many large size-low speed diesel engines, instead of steam turbines, are used for the industrial electric power generating plants due to their economic advantage of low specific fuel consumption. But it is very important to control their electric power fluctuation problems for the purpose of smooth parallel operation with existing power plants. In this paper the fluctuation problem of KEPCO Nam-cheju No.1 generator driven by diesel ngine(B & W 7K 60MC, 13931x138.5RPM) is investigated with analysis of torsional vibration of which 4th harmonic component is related to its power fluctuation. The problem can be improved by modification of cylinder arrangement and flywheel position in reverse sequence, equalizing the combustion gas pressure of all cylinder and installation of torsional vibration damper enlarged 30%(Je=7287Kg.m2) and high quality balancing of generator rotor.

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A Study on the Kernel Formation & Development for Lean Burn and EGR Engine (희박연소 및 EGR 엔진에서 초기 화염액 생성 및 성장에 관한 연구)

  • 송정훈;선우명호
    • Transactions of the Korean Society of Automotive Engineers
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    • v.7 no.8
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    • pp.24-33
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    • 1999
  • This paper investigate the effects of the variations of engine operation condition in the flame kernel formation and developmnet . A model for calculating the initial kernel development in spark ignition engines is formualted. It considered input of electrical energy, combustion energy release and heat transfer to the spark plyg, cylinder head, and unburned mixture. The model also takes into accounts strain rate of initial kernel and residual gas fraction. The breakdown process and the subsequent electrical power input initially control the kernel growth while intermediate growth is mainly dominated by diffusion or conduction. Then, the flame propagates by the chemical energy and turbulent flame expansion. Flame kernel development also influenced by engine operating conditions, for example, EGR rate, air-fuel ration and intake manifold pressure.

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Performance Analysis of Carbon Canister for Reducing Evaporative Emissions in a Gasoline Automotive Engine

  • Chung, Yon-Jong;Cho, Gyu-Sang;Erickson, Paul A.;Han, Sung-Bin
    • Journal of Energy Engineering
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    • v.17 no.2
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    • pp.47-53
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    • 2008
  • The objective of this paper is to clarify the flow characteristic, velocity distribution, pressure loss, and other such fundamental data for the canister during loading and purging. The amount of gas that is loaded increases as the loading rate is decreased and the time increased, and the purging improves as the purge rate is increased. The hydrocarbons that are purged initially have a high concentration, and a large amount is purged. During loading and purging, the temperature initially increases and decreases drastically due to heat generation and heat loss.