• Title/Summary/Keyword: Fuel pressure control

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A Study on Combustion and exhaust Emission Characteristics with Air Charge in Compression Ignition Diesel Engine (압축착화 디젤기관의 흡기조성에 따른 연소 및 배기배출물 특성에 대한 연구)

  • Kim, Gi-Bok;Kim, Chi-Won;Yoon, Chang-Sik;Han, Sung-Hyun
    • Journal of the Korean Society of Industry Convergence
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    • v.18 no.4
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    • pp.207-215
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    • 2015
  • Since the oil shock of 1970's there was a strong upward tendency for the use of the high viscosity and poorer quality fuels. Therefore the misfiring engine occurs due to the decrease of quantity injected for lean burn and emission control in CI diesel engine. In this study, it is designed and used the test bed which is installed with turbocharger and intercooler. In addition to equipped using CRDI by controlling injection timing with mapping modulator, it has been tested and analyzed the engine performance, combustion characteristics, and emission as operating parameters.

TRANSIENT PERFORMANCE OF AN SI ENGINE BY TRANSIENT RESPONSE SPECIFICATIONS

  • Kwark, J.H.;Jeon, C.H.;Chang, Y.J.
    • International Journal of Automotive Technology
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    • v.4 no.3
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    • pp.109-117
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    • 2003
  • The analysis and evaluation of the transient performance by the transient response specifications under various acceleration speeds and types based on driver's typical acceleration habit are implemented by the experimental study to provide the appropriate direction for the transient control in a gasoline engine. The concept of the transient response specifications which consist of delay time, rising time, maximum overshoot and settling time, and the analysis method using them are introduced to evaluate the characteristics of the transient performance quantitatively. Furthermore four acceleration speeds and four acceleration types are set respectively to realize the various transient states which are similar to the real drive. Several performance parameters in terms of engine speed, manifold absolute pressure, fuel injection duration and air excess ratio are measured simultaneously during the various acceleration using a throttle actuator controlled by a PC. The transient response specifications characterized well the transient performance for the various acceleration speed and types quantitatively. Delay and rising time with increment of the acceleration speed became shorter, but settling time did longer. Intensified acceleration type appeared to be the most economical in view of fuel consumption, and linear acceleration type was found to have the least harmful emission concentration.

Aerodynamic control capability of a wing-flap in hypersonic, rarefied regime

  • Zuppardi, Gennaro
    • Advances in aircraft and spacecraft science
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    • v.2 no.1
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    • pp.45-56
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    • 2015
  • The attitude aerodynamic control is an important subject in the design of an aerospace plane. Usually, at high altitudes, this control is fulfilled by thrusters so that the implementation of an aerodynamic control of the vehicle has the advantage of reducing the amount of thrusters fuel to be loaded on board. In the present paper, the efficiency of a wing-flap has been evaluated considering a NACA 0010 airfoil with a trailing edge flap of length equal to 35% of the chord. Computational tests have been carried out in hypersonic, rarefied flow by a direct simulation Monte Carlo code at the altitudes of 65 and 85 km, in the range of angle of attack 0-40 deg. and with flap deflection equal to 0, 15 and 30 deg.. Effects of the flap deflection have been quantified by the variations of the aerodynamic force and of the longitudinal moment. The shock wave-boundary layer interaction and the shock wave-shock wave interaction have been also considered. A possible interaction of the leading edge shock wave and of the shock wave arising from the vertex of the convex corner, produced on the lower surface of the airfoil when the flap is deflected, generates a shock wave whose intensity is stronger than those of the two interacting shock waves. This produces a consistent increment of pressure and heat flux on the lower surface of the flap, where a thermal protection system is required.

Comparison of emission characteristics between fuel injection systems with echanical cam and electric control type on low speed 2 stroke diesel engine for ship propulsion (선박추진용 기계적 캠 구동식 및 전자제어식 연료분사 시스템을 가진 저속 2행정 디젤엔진의 배기특성 비교)

  • Lee, Sang Deuk;Koh, Dae Kwon;Jung, Suk Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.6
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    • pp.611-616
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    • 2013
  • Many researches have been carried out consistently for the green ship owing to its economic increasement, efficiency and convenience. One of them is an electronic controlled marine diesel engine. However, we are suffered from dissemination of above engine, due to its anxiety about safety and reliability. In order to solve these problems in this study, emission characteristics test of main propulsive two-stroke diesel engine, equipped both electronic control and cam drive fuel injection systems, has been performed and evaluated under the various load conditions. From the test results, we have confirmed that exhaust gas emission characteristics of the electronic control system is similar to the cam drive system in eco-mode operation, but NOx in emission mode has been decreased 100ppm or more in full load condition. HC emission from the electronic control system is decreased 10~20ppm at 50% load, and 35~40ppm at 25% load in comparison to cam drive system. In fuel consumption, it is considered that 7g/kWh is decreased than the value of cam drive system at 700bar of injection pressure, which is 200bar higher than cam drive system.

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.

Operating Strategy Optimization of Metal Hydride based Hydrogen Supply System (수소저장합금을 이용하는 수소공급시스템의 운전 방법 최적화)

  • Kim, Byung-Jun;Sung, Hae-Jung;Lee, Young-Duk;Lee, Sang-Min;Cho, Ju-Hyeong;Ahn, Kook-Young
    • Journal of Hydrogen and New Energy
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    • v.22 no.5
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    • pp.625-633
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    • 2011
  • Characteristics of a commercial metal hydride (MH) hydrogen supply system have been investigated and an operating strategy was developed based on the experimental data. As a prior step, charging/discharging capacity, thermal properties such as heat capacity, heat of reaction of MH system were experimentally measured. And then P-C-T data for various operating conditions were collected and a correlation between P, C and T predicting the behavior of MH was derived. Based on the basic experimental data, an operating strategy of MH system was developed, in which the hot water temperature supplied into the water jacket of MH was controlled depending on the pressure of MH, thereby the pressure of MH could be maintained at a suitable range. By adjusting the temperature of hot water from 40C to 60C, the maximum discharging capacity of hydrogen could be increased by 4.7%, and consequently more stable hydrogen supply and longer operation time of fuel cell system could be achieved.

A Numerical Study Of Flow Control Valve to Flow Characteristics by Pressure Difference for Hydrogen Station (수소충전소용 유량제어 밸브의 차압에 따른 유동특성에 대한 수치해석적 연구)

  • Nam, Chung-Woo;Kim, Rak-Min;Kim, Hyun-Hyo
    • Journal of the Korean Institute of Gas
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    • v.25 no.2
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    • pp.28-33
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    • 2021
  • With the recent growing interest in eco-friendly cars, as interest in eco-friendly cars increases, interest and purchase of hydrogen fuel cell vehicles that do not emit pollutants are increasing. Recently, the government is supporting the expansion of hydrogen charging station and localization of core parts according to the government's hydrogen energy dissemination policy. In this study, the flow characteristics of the hydrogen flow control valve were investigated. As the differential pressure increases, the mass flow rate and flow coefficient tend to be different from the volume flow rate. And it was confirmed that it affects the hydrogen temperature due to the nozzle effect in the bottleneck section, and the change in density affects the mass flow rate.

Structural Static Test for Validation of Structural Integrity of Fuel Pylon under Flight Load Conditions (비행하중조건에서 연료 파일런의 구조 건전성 검증을 위한 구조 정적시험)

  • Kim, Hyun-gi;Kim, Sungchan;Choi, Hyun-kyung;Hong, Seung-ho;Kim, Sang-Hyuck
    • Journal of Aerospace System Engineering
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    • v.16 no.1
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    • pp.97-103
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    • 2022
  • An aircraft component can only be mounted on an aircraft if it has been certified to have a structural robustness under flight load conditions. Among the major components of the aircraft, a pylon is a structure that connects external equipment such as an engine, and external attachments with the main wing of an aircraft and transmits the loads acting on it to the main structure of the aircraft. In civil aircraft, when there is an incident of fire in the engine area, the pylon prevents the fire from spreading to the wings. This study presents the results of structural static tests performed to verify the structural robustness of a fuel pylon used to mount external fuel tank in an aircraft. In the main text, we present the test set-up diagram consisting of test fixture, hydraulic pressure unit, load control system, and data acquisition equipment used in the structure static test of the fuel pylon. In addition, we introduce the software that controls the load actuator, and provide a test profile for each test load condition. As a result of the structural static test, it was found that the load actuator was properly controlled within the allowable error range in each test, and the reliability of the numerical analysis was verified by comparing the numerical analysis results and the strain obtained from the structural test at the main positions of the test specimen. In conclusion, it was proved that the fuel pylon covered in this study has sufficient structural strength for the required load conditions through structural static tests.

Dynamic Characteristics of Electro-hydraulic Proportional Valve for an Independent Metering Valve of Excavator (굴삭기 IMV용 비례전자밸브의 동특성)

  • Kang, Chang Nam;Yun, So Nam;Jeong, Hwang Hoon;Kim, Moon Gon
    • Journal of Drive and Control
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    • v.15 no.2
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    • pp.46-51
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    • 2018
  • Many research studies have been carried out related to saving energy and environmental pollution in the field of construction machinery. The best solution for reducing the related environmental pollution is to reduce fuel consumption by upgrading the energy efficiency of machinery used in this field. An efficiency upgrade in the field of construction machinery would mean minimizing the pressure loss in hydraulic pipe lines or achieving optimal operating conditions while responding to a load. One way to achieve this is to make an equivalent circuit, like an electrohydrostatic actuator, or to improve the spool type valve using the 4/3 way method. This study deals with an electrohydraulic proportional flow control valve. SimulationX software is used as a simulation tool for analyzing the dynamic characteristics. The analysis results, including the performance and characteristics of design parameters, are discussed and the validity of the theoretical analysis is also evaluated.

A Study on Characteristics of Performance and Emission by CRDI Engine's Injection Strategy (커먼레일 디젤기관에서 분사전략에 따른 성능 및 배출가스에 관한 연구)

  • Eom, Dong-Seop;Ko, Dong-Kyun;Ra, Wan-Yong;Lee, Seang-Wock
    • Journal of ILASS-Korea
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    • v.16 no.3
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    • pp.134-139
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    • 2011
  • Recent research has focused on engine combustion technology as well as application of after-treatment in order to comply with emission regulation. However, it is much more efficient way to control emissions from engine itself and furthermore research on engine control will provide the direction of after-treatment technology in future. Furthermore, emission standard regulation for passenger diesel vehicles has been stringent compared to others and nano-particles will be included in EURO6 regulation in Europe and similar emission standard will be introduced in Korea. A 3.0 liter high speed diesel engine equipped with by CRDI system of 160MPa injection pressure, and an intake/exhaust system of V type 6 cylinder turbo-intercooler was applied. The injection duration and injection quantity, pilot injection types which are related to CRDI and air/fuel ratio control applied by EVGT were changed simultaneously. Standard experiment procedure constituted dilution apparatus and CPC system to collect nano-particles and these test results were compared with regulated materials of CO, HC, NOx and investigated their relations and characteristics of nano-particles.