• Title/Summary/Keyword: Fuel pressure control

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A Study on the Pressure Increment of Fuel Pump for GDI Engines Considering Leakage Flows (누설특성을 고려한 GDI 엔진용 연료펌프의 고압생성 증진에 관한 연구)

  • Na, Byung-Chul;Kim, Byoung-Soo;Choi, Suk-Woo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.6
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    • pp.785-791
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    • 2000
  • GDI (Gasoline Direct Injection) engines are considered as one of the candidates for next generation engines of passenger cars, which reduce exhaust emissions and fuel consumption. In GOI engines, a high-pressure gasoline supply system is required to directly inject the fuel to combustion chambers. Because of low lubricity of gasoline fuel, the clearance between a plunger and a barrel in GDI fuel pumps is too wide to achieve smooth hydrodynamic lubrication. Thus, it is difficult to generate high-pressure condition in GDI fuel pump since large amount of leakage flow occurs between the plunger and the barrel In this study, an optimum plunger design is presented to minimize leakage in the aspect of flow control. This paper analyzes leakage flow characteristics in the clearance to improve pumping performance of GDI fuel pumps. Effects of groove in the plunger are studied according to variations of depth and width. Evaluations of pumping performance are determined by the amount of pressure drop in the leakage path assuming a constant leakage flows. Both of turbulence and incompressible models are introduced in CFD (Computational Fluid Dynamics) analysis. Design parameters have been introduced to minimize leakage in limited space, and a methodological study on geometrical optimization has been conducted. As results of CFD analysis in various geometrical cases, optimum groove depths have been found to generate maximum sealing effects on gasoline fuel between the plunger and the barrel. This procedure offers a methodological way of an enhancement of plunger design for high-pressure GDI fuel pumps.

Method of Test for Combustion Instability and Control at Model Combustor of Supersonic Engine (초음속 엔진 모델 연소기에서의 연소불안정 및 제어 시험 기법)

  • Choi, Ho-Jin;Hwang, Yong-Seok;Jin, You-In;Park, Ik-Soo;Yoon, Hyun-Gull;Kang, Sang-Hun;Lee, Yang-Ji
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.05a
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    • pp.111-115
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    • 2009
  • The method of test for observing the combustion instability and controling the instability actively by using secondary injection of fuel through flame stabilizer was studied by constructing model combustor of supersonic engine. The frequency of combustion instability was detected by measuring the pressure of combustor using pressure sensor and by optical sensing of flame intensity. Electro-magnetic valve was adopted as actuator for active control and the characteristics of modulated fuel was studied by measured pressure of valve outlet and scattering signal of spray at secondary fuel injection.

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Effect of Ambient Conditions on the Soot Generation of Decane Fuel Droplet (분위기 조건이 Decane 액적의 Soot 생성에 미치는 영향)

  • Lim, Young Chan;Suh, Hyun Kyu
    • Journal of ILASS-Korea
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    • v.19 no.4
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    • pp.211-215
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    • 2014
  • The main purpose of this study is to provide basic information of droplet soot generation of decane fuel. To achieve this, this paper presents the experimental results on the decane droplet combustion conducted under various ambient pressure($P_{amb}$), and oxygen concentration($O_2$) conditions. At the same time, the experimental study was conducted in terms of soot volume fraction($f_v$) and its maximum value. Also, visualization of single fuel droplet was conducted by high resolution CCD camera and ambient pressure($P_{amb}$) and oxygen concentration($O_2$) was changed by control system. It was revealed that higher ambient pressure($P_{amb}$), and oxygen concentration($O_2$) enhanced the soot generation and improved the maximum soot volume fraction( $f_v$).

Effects of Reynolds Number and Shape of Manifold on Flow Rate in Separator for Polymer Electrolyte Fuel Cell (ICCAS 2004)

  • Huang, Chaii;Ozawa, Yoshikuni;Ennoji, Hisayuki;Iijima, Toshio
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.68-71
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    • 2004
  • Recently, a great deal of research and development of a fuel cell have been carried out to solve problems on the drain of fossil fuel, air pollution and global warning. In order to improve the efficiency of a fuel cell, it is necessary to clarify the flow in separator. In this study, distributions of velocity flow rate and pressure, and streamlines are examined in detail from numerical analysis with CFD code. In the experiment the distribution of flow rate is measured and flow in the each grooves of the separator is visualized by dye method changing Reynolds number. Furthermore, effects of size of the inlet and outlet manifolds and shape of ribs near the inlet outlet on the distributions of flow and pressure are examined.

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Combustion Characteristic of Non-esterified Bio-diesel Oil at Lower Common Rail Pressure (저 커먼레일 압력에서 비에스테르화 바이오 디젤유의 연소특성)

  • Lee, Sang-Deuk;Koh, Dae-Kwon;Jung, Suk-Ho
    • Journal of Power System Engineering
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    • v.17 no.6
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    • pp.11-17
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    • 2013
  • Esterified bio-diesel oil is normally used as blend oil of 3% that and 97% diesel fuel in Korea. Since specifics of it is similar to that of diesel fuel, availability of non-esterified bio-diesel oil that has a lower expenses of manufacturing is worthy of attention. However, bio-diesel oil has a demerit which it emits typically more NOx emission than diesel fuel. In this study, characteristic tests using blending oil with 95% gas oil and 5% bio-diesel oil were achieved at lower common rail pressure in order to improve this demerit. It was noticed that non-esterified bio-diesel oil has more similar characteristics to diesel fuel than esterified bio-diesel oil and it emits more NO emission by fuel NO mechanism.

A Study on the Effect of Cycle Variation on Scavenging pressure in 2-Stroke Diesel Engine (2행정 디젤엔진의 소기압력이 사이클변동에 미치는 영향에 관한 연구)

  • Yoon, Chang-Sik;Kim, Chi-Won;Kim, Gi-Bok
    • Journal of the Korean Society of Industry Convergence
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    • v.19 no.3
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    • pp.154-159
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    • 2016
  • Recently it has been focused that the automobile engine has developed in a strong upward tendency for the use of the high viscosity and poorer quality fuels in achieving the high performance, fuel economy, and emission reduction. Therefore it is not easy to solve the problems between low specific fuel consumption, and exhaust emission control at automotive engine In this study, it is designed and used the test bed which is installed with fuel injector controller. In addition to equipped engine using CRDI by controlling the injection timing with modulator, it has tested and analyzed the engine cycle variation characteristics, as it is varied that they are the operating parameters: fuel injected quantity, injection timing, engine speed and scavenging pressure.

A Control of CVT Hydraulic System using Embedded System (임베디드 시스템을 이용한 CVT 유압시스템 제어)

  • Han, K.W.;Ryu, W.S.;Jang, I.G.;Jean, J.W.;Kim, H.S.;Hwang, S.H.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.4 no.1
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    • pp.18-24
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    • 2007
  • The continuously variable transmission (CVT) of which speed ratio can change continuously in a fixed range has the benefits of low fuel consumption and exhaust gas because it enables the engine of a vehicle to operate in a high efficiency range regardless of vehicle speed. The speed ratio of belt type CVT is controlled by adjusting line pressure. The one of the line pressure control methods, mechanical-hydraulic control is usually adopting VDT's control method, in which the secondary solenoid valve has two functions both a regulator and a line pressure controller. However, this control method could not show the high performance of CVT with optimal driving capability because of the limitation of simple control algorithm, and it could not gain market share sufficiently in spite of the advantage of CVT with low fuel consumption. On the other hand, the electro-hydraulic control method gives the enhancement of power performance and low fuel consumption by implementing various driving mode using the proportional control or PWM control. The key of CVT technique is to develop a control algorithm of the electro-hydraulic solenoid valve in order to implement the speed ratio efficiently. In this paper, the line pressure control algorithm is proposed and the hydraulic system is controlled using metal belt type CVT test rig and the embedded ECU platform.

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The Effect of Fuel Injection Timing on the Combustion and Emission Characteristics of a Natural Gas Fueled Engine at Part Loads

  • Cho, Haeng-Muk
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.7
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    • pp.1013-1018
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    • 2008
  • For a sequential port fuel injection natural gas engine, its combustion and emission characteristics at low loads are crucial to meet light duty vehicle emission regulations. Fuel injection timing is an important parameter related to the mixture formation in the cylinder. Its effect on the combustion and emission characteristics of a natural gas engine were investigated at 0.2 MPa brake mean effective pressure (BMEP)/2000 rpm and 0.26 MPa BMEP/1500 rpm. The results show that early fuel injection timing is beneficial to the reduction of the coefficient of variation (COV) of indicated mean effective pressure (IMEP) under lean burn conditions and to extending the lean burn limits at the given loads. When relative air/fuel ratio is over 1.3, fuel injection timing has a relatively large effect on engine.out emissions. The levels of NOx emissions are more sensitive to the fuel injection timing at 0.26 MPa BMEP/1500 rpm. An early fuel injection timing under lean burn conditions can be used to control engine out NOx emissions.

Study on Characteristics of Change of Physical/Chemical property of Refined Fuel Oil(Reduced-pressure) by Mixing with By-product Fuel Oil(No. 2) (부생연료유(2호) 혼합에 따른 정제연료유(감압)의 물성 변화 특성 연구)

  • Doe, Jin-woo;Lim, Tae-yun;Yim, Eui-soon;Lee, Joung-min;Kang, Hyung-kyu
    • Journal of the Korean Applied Science and Technology
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    • v.35 no.4
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    • pp.1349-1358
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    • 2018
  • In addition to responding to the environmental pollution caused by fossil fuels, the enforcement of Renewable Fuel Standard(RFS) system has increased the utilization of renewable energy such as refined fuels oil. The by-product fuel oil(No. 2) and the refined fuel oil(reduced-pressure) are strictly regulated by the domestic legislation and the chemical property changes of the refined fuel oil(reduced-pressure) mixed with the by-product fuel oil(No. 2) were analyzed. As a result of analyzing the physical properties of refined fuel oil(reduced pressure) obtained by mixing 1 : 1 of by-product fuel oil(No. 2), it satisfied the quality standards stipulated by the domestic Enforcement Decree of the Wastes Control Act. However, the results of the additional tests related to the fuel showed a high aromatic content. The high content of aromatic in a fuel is likely to cause the soot and ehaust emission gas during the combustion of the used equipment.

A High Pressure Fuel Control and its Injection Characteristics (고압 연료 제어와 분사 특성)

  • Kim, S.H.;Lee, Y.G.;Kim, J.U.;Kim, E.S.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.6
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    • pp.123-133
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    • 1995
  • An injection control valve(ICV) was designed to control the fuel flow between a common rail and an injector with two commercial solenoids. To improve the performance of ICV, the characteristic method was applied. With this method, the flow characteristics in the ICV and the injector were studied and the parameters which affect the injection characteristics were also studied. From this study, following results were obtained. The injection duration can be controlled and with modifications of the effective valve stroke of ICV, the injection quantity and duration can be reduced to desired amount. Also the injection quantity and pressure can be controlled by reducing the hole size of the injector without the variation of the injection duration. For some conditions, the desired injection characteristics can be obtained by the changes of the valve timing, the effective valve stroke, the open pressure of the injector and the hole size of the injector.

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