• Title/Summary/Keyword: Direct. Injection

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The Combustion and Emission Characteristics with Increased Fuel Injection Pressure in a Gasoline Direct Injection Engine (가솔린 직접 분사식 엔진에서 연료 분사 압력 증가에 따른 연소 및 배기 배출물 특성)

  • Lee, Junsun;Lee, Yonggyu
    • Journal of ILASS-Korea
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    • v.22 no.1
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    • pp.1-7
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    • 2017
  • Recently, Performance and fuel efficiency of gasoline engines have been improved by adopting direct injection (DI) system instead of port fuel injection (PFI) system. However, injecting gasoline fuel directly into the cylinder significantly reduces the time available for mixing and evaporation. Consequently, particulate matters(PM) emissions increase. Moreover, as the emission regulations are getting more stringent, not only the mass but also the total number of PM should be reduced to satisfy the Euro VI regulations. Increasing the fuel injection pressure is one of the methods to meet this challenge. In this study, the effects of increased fuel injection pressures on combustion and emission characteristics were experimentally examined at several part load conditions in a 1.6 liter commercial gasoline direct injection engine. The main combustion durations decreased about $2{\sim}3^{\circ}$ in crank angle base by increasing the fuel injection pressure due to enhanced air-fuel mixing characteristics. The exhaust emissions and number concentration distributions of PM with particle sizes were also compared. Due to enhanced combustion characteristics, THC emissions decreased, whereas NOx emissions increased. Also, the number concentrations of PM, larger than 10 nm, also significantly decreased.

A Study on Driving Stability of In-cylinder Direct Injection Stratified Charge Gasoline Engine - Effects on HR rate and $COV_{imep}$ of Fuel Injection Pressure and Load Variations - (연소실 직접분사식 성층급기 가솔린기관의 구동안정성에 관한 연구 -열방출율과 도시평균유효압력 변동에 미치는 연료분사압력과 부하변동의 영향-)

  • 이상만;이근오
    • Journal of the Korean Society of Safety
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    • v.13 no.3
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    • pp.3-10
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    • 1998
  • In general, the stratified charge for direct injection gasoline engine should be introduced to achieve ultra-lean combustion scheme. In order to apply the concept of stratified charge into direct injection gasoline engine, a reflector was adapted on cylinder head. An installation of the reflector in front of the injector nozzle leads the mixture to be rich near spark plug. Therefore, the mixture near the spark plug is locally ich to ignite while the lean mixture is wholly introduced into the combustion chamber. In this paper, the characteristics of combustion is analyzed with the variations of injection pressure and load in a stratified-charge direct injection single cylinder gasoline engine.

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A Direct Injection-mixing Total-flow-control Boom Sprayer System (주입식 총유량 자동제어방식 분관 방제기의 개발)

  • 구영모
    • Journal of Biosystems Engineering
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    • v.21 no.2
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    • pp.155-166
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    • 1996
  • A direct injection sprayer was designed using the concepts of injection mixing and total flow control, flowrate-based system compensating for the variation of forwarding speed. A metered rate, proportionally to the actual diluent flow rate, of a tracer chemical was injected directly into the diluent stream. The injection of chemical may improve the precision and safety of chemical application process. The control system was evaluated for the variables of the control interval, tolerances and sensitivities of flow regulation valve and injection pump. Performance of the system was assessed as that the response time of flow rate, response time of injection rate, absolute steady state error, and the coefficient of variance(C.V.) of concentration were 8.5 and -0.53 seconds, 0.067 lpm(0.8%) and 3.15%, respectively, at optimal parameters of control interval of 1.0 sec, fast sensitivity of flow regulation valve, medium sensitivity of injection pump and medium tolerance of flow rate. Performance of the system can be improved by increasing the sensitivity of flow regulating valve and employing a high resolution velocimeter, such as Doppler radar.

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Injection Media Affecting Expression of Transgene Introduced by Direct in vivo Injection into Olive Flounder (Paralichthys of olivaceus) Muscle

  • Dong Soo Kim;Chang Hwa Jeong;Young Sun Cho;Yoon Kwon Nam
    • Journal of Aquaculture
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    • v.12 no.1
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    • pp.71-77
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    • 1999
  • The potential utility of injection media (sucrose, PEG, and liposome) was demonstrated for direct gene transfer into olive flounder (Paralichthys olivaceus) muscles. Based on the use of sucrose (final cone. 20%), PEG 8,000 (final cone. 10%) or liposome (twice us of DNA injected), the present injection strategy significantly improved the level of transgene expression as well as persistent duration of expression. The increased amounts of expression in DNA injection with sucrose, PEG, and liposome were as high as from 2.1 to 4.9-folds of conventional TE-based DNA injection. The best result was obtained from injections of liposome-encapsulated DNA in which the expression was detectable at least 32 days after injection when compared to only 8-16 days from TE-based injections.

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A Study on the Measurement of Individual Spray Cone Angle from Gasoline Direct Injection Injector using Spray Pattern Analysis (분무패턴 분석을 이용한 가솔린 직접 분사식 인젝터의 개별 분무플럼 분무각 측정 방법에 대한 연구)

  • Park, Jeonghyun;Cho, Hanbin;Park, Suhan
    • Journal of ILASS-Korea
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    • v.25 no.2
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    • pp.51-59
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    • 2020
  • The purpose of this study is to propose and compare methods for measuring individual spray cone angles using spray cross-section images. In direct injection gasoline engines, it was believed that the distribution of air-fuel mixture in the combustion chamber directly affected combustion performance and emission formation. However, since gasoline direct injection (GDI) injectors have a small injection angle, interference between individual spray plumes occurs. Therefore, GDI injectors have only measured the spray angle of the entire spray. To overcome these limitations, three methods of indirectly measuring the spray cone angles of individual spray plume were presented and compared by forming sheet beams using Nd:YAG laser and acquiring spray cross-section images. Each method currently has advantages and disadvantages, and research to apply the method suitable for various GDI injectors needs to be continued.

The Characteristic of Power and Emission for Heavy-duty CNG Engine with Direct Injection according to Various Compression Ratio (대형 직접분사식 CNG 기관의 압축비 변화에 따른 기관출력 및 배기특성)

  • Nam, Dae-Woo;Trandangquoc, Trandangquoc;Lee, Jong-Tai
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.3090-3095
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    • 2008
  • In this study, variable compression ratio system(VCRS) was applied on the heavy-duty CNG engine and the characteristics of power and emission was investigated according to the increasing of compression ratio. As compression ratio increasing, the increasing of thermal efficiency in direct injection is three times higher than that in port injection. The emission of HC and CO in direct injection is reduced about 14.2%, 17.7% but NOx is increased because of increasing temperature in cylinder.

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Atomization Characteristics of Fuel Spray in Fuel Injector in Gasoline Direct-Injection Engine (가솔린 직분식 엔진 인젝터의 연료 분무 미립화 특성)

  • Lee, C.S.;Lee, K.H.;Choi, S.C.;Kwon, S.I.
    • Journal of ILASS-Korea
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    • v.4 no.2
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    • pp.33-39
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    • 1999
  • This paper presents the spray atomization characteristics of the high-pressure gasoline injector for the direct-injection gasoline engine. The gasoline sprays of the injector were minted into a pressurized spray chamber with a optical access at various ambient pressures. The atomization characteristics of fuel spray such as mean diameter, mean velocity of droplet were measured by the phase Doppler particle analyzer system. In order to investigate the effect of fuel injection pressure on the quantitative characteristics of spray, the global visualization and experiment of particle measurement in the fuel spray were investigated at 3, 5 and 7 MPa of injection pressure under different ambient pressure in the spray chamber. Based on the results of this work, the fuel injection pressure of fuel injector in gasoline direct-injection engine have influence upon distribution of the mean velocity and droplet size of fuel spray. Also, the influence of injection pressure on the velocity distribution at various measuring location were investigated.

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A Study on Direct Injection Stratified Charge Combustion with Spark Ignition in Constant Volume Bomb (정적 용기내의 직접분사식 스파크 점화 성층 연소에 관한 연구)

  • Hong, M.S.;Kim, K.S.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.5
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    • pp.30-40
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    • 1994
  • The direct-injection stratified-charge engine has the advantages of higher thermal efficiency and less CO and $NO_x$ emission levels than conventional spark ignition engines. However, its actual utilization is prevented by high unburned hydrocarbon emission levels during light-load operations. In this paper, fundamental studies were carried out using a pancake type constant volume bomb. The effects of intensification of local premixing by tangential and radial fuel injection were examined experimentally. Unburned hydrocarbon emission levels with radial fuel injection were shown to be lower than those of tangential fuel injection cases. The stratification and mixing process of fuel jet and combustion process were observed by schlieren photography.

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A Study on Ignition Probability and Combustion Characteristics of Low Pressure Direct Injection LPG according to a Function of Ambient Condition (분위기 조건 변화에 따른 저압 직접분사식 LPG의 점화성 및 연소특성 연구)

  • Chung, Sung-Sik;Hwang, Seong-Ill;Yeom, Jeong-Kuk;Jeon, Byong-Yeul
    • Journal of Power System Engineering
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    • v.20 no.2
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    • pp.32-42
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    • 2016
  • Under part load condition of spark-ignition engine, pumping loss had great effect on engine efficiency. To reduce pumping loss, the study designed spark-ignited engines to make direct spray of gasoline to combustion chamber. In spark-ignited direct-injection engines, ignition probability is important for successful combustion and flame propagation characteristics are also different from pre-mixed combustion. This study designed a visualization testing device to study ignition probability of spark-ignited direct-injection LPG fuel and combustion flame characteristics. This visualization device consists of combustion chamber, fuel supply system, air supply system, electronic control system and data acquisition system. Ambient pressure, ambient temperature and ambient air flow velocity are important parameters on ignition probability of LPG-air mixture and flame propagation characteristics, and the study also found that sprayed LPG fuel can be directly ignited by spark-plug under proper ambient conditions. To all successful cases of ignition, the study recorded flame propagation image in digital method through ICCD camera and its flame propagation characteristics were analyzed.