• 대한기계학회논문집B
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• 제24권6호
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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.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.67-73
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• 2002

The characteristics of fuel spray influence on the engine performances such as power, fuel economy and emissions. therefore, the measurement of fuel spray characteristics is very important for the improvement of heat engine. The factor which controls the fuel spray is injection pressure, ambient pressure, engine speed et al.. In :his study, We measured spray angle, spray penetration and spray tip velocity considering injection pressure(10,14㎫), ambient pressure(3,4,5㎫), fuel pump speed(500,700,900rpm) in the high temperature and pressure chamber. Experimental results are summarized as follows: 1) Injection pressure influence on the characteristics of spray namely As Injection pressure Is increased, spray angle is decreased but spray penetration and spray tip velocity is increased. 2) Spray angle, spray penetration is increased by increasing the fuel pump speed. 3) Ambient pressure plays an important role in spray characteristics.

• 한국가스학회지
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• 제12권2호
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• pp.12-17
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• 2008

강화되는 배출가스 규제에 대응하기 위한 대책으로 LPG 차량에 적용되고 있는 제3세대 LPG 연료공급방식인 LPLi(Liquid Phase LPG Injection)은 LPG 연료를 펌프를 이용해서 고압의 액상연료를 공급하는 것이 가장 핵심적인 기술이다. 그러나 LPG 연료의 경우 저점도, 저비등점의 물리적 특성을 갖는 가스연료로서 기존의 가솔린 또는 디젤용 펌프를 사용할 경우 성능 및 효율이 달라질 수 있다. 본 연구에서는 가솔린 연료 펌프의 임펠라 방식을 응용 변형시켜서 LPG연료용으로 개발된 펌프를 이용하여 다양한 온도와 연료조성 조건에서 초기토출성능 및 효율을 파악하고, 기존 펌프의 단점을 극복할 수 있는 펌프방식의 적용가능성 여부를 판단하고자 한다.

• 항공우주시스템공학회지
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• 제17권5호
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• pp.11-18
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• 2023

The architecture of the Fuel Thermal Management System (FTMS) in a commercial aircraft engine was built to model and simulate the fuel system. The study shows the thermal interactions between the fuel and engine lubrication oil through the mission profile of a high bypass ratio, two-spool turbofan engine. Fuel temperature was monitored as it flowed through each sub-component of the fuel system during the mission. The heat load in the fuel system strongly depended on the fuel flow rate, and was significantly increased for the periods of cruise and descent with decrease of fuel flow rate, rather than for the periods of take-off. Due to the thermal interaction in the pump housing, the fuel temperature at the outlet of the low-pressure pump was increased (4.0, 9.2, and 30.0) % over the case without thermal interaction for take-off, cruise, and descent, respectively.

• 한국가스학회지
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• 제26권4호
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• pp.1-8
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• 2022

디젤엔진의 대체 연료로 연구되고 있는 청정연료인 DME는 디젤엔진의 중요한 문제 중 하나인 배기가스를 줄일 수 있으며, 세탄가와 산소함유량이 매우 높다. DME는 LPG와 유사한 특성을 가진 연료로 LPG 유통 인프라를 사용할 수 있다. 본 연구에서는 플런저식 고압펌프의 성능평가를 위해 토출된 질량유량에 대한 기초 데이터베이스 구축을 목표로 하였으며, 커먼레일 압력과 모터 회전속도를 변화시켜 플런저식 고압펌프의 질량유량을 분석하였다. 실험 조건은 커먼레일 압력을 300 bar, 400 bar, 500 bar 로 변경하였고, 모터 회전 속도를 300 rpm에서 1000 rpm 으로 증가시켰다. 실험 결과 두 경우 모두 질량유량이 증가하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.13-16
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• 2007

본 연구에서는 무인기용 추진 시스템으로 연료전지를 사용하였다. 연료전지 추진 시스템은 고항속 무인기를 위한 고에너지 밀도를 갖는 이상적인 대체 동력원이다. 연료전지 동력 시스템은 기폰 배터리의 5배 이상의 에너지 밀도를 제공한다. 액체상태로 저장되는 수소화붕소나트륨을 수소원으로 사용하였다. 수소 생성 시스템은 촉매 반응기, 펌프, 연료, 카트리지, 분리기로 구성된다. 연료전지와 리륨-폴리머 배터리의 하이브리드 동력 관리 시스템이 개발되었다. 모터, 펌프, 팬은 연료전지 시스댐의 피트백 신호에 따라 배터리 동력으로 작동되고 배터리는 연료전지의 잉여 동력으로 재충전되었다.

• 대한기계학회논문집B
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• 제39권5호
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• pp.455-461
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• 2015

고압연료펌프는 GDI 엔진의 핵심 구성요소로써, 엔진출력 및 연료 효율을 향상시키기 위해서는 고압연료펌프의 유동특성을 연구하는 것이 필요하다. 본 연구에서는 유압해석툴인 AMEsim을 이용하여 고압연료펌프의 통합 모델을 생성하여 유동해석을 수행하였다. 하지만, AMEsim은 시스템 해석을 위한 1차원 모델이므로 복잡한 유동현상이 발생하는 부근에서의 해석 결과는 정확하지 않은 단점이 있으므로 본 연구에서는 전산해석프로그램인 Fluent를 이용하여 난류유동이 발생하는 체크밸브의 흡입부와 토출부에서 유량과 알짜힘을 계산하였다. 다양한 압력조건과 밸브 간극변화에 따른 CFD 해석 결과는 AMEsim모델에 대한 룩업테이블로 사용되어 AMEsim의 결과를 보완함으로써 고압연료펌프에 대한 성능 분석결과의 정확성을 향상시키는 결과를 얻을 수 있었다.

• 한국자동차공학회논문집
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• 제22권5호
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• pp.20-28
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• 2014

The high velocity oxygen fuel spraying (HVOF) is a kind of surface modification process technology to form the sprayed coating layer after spraying the powder to molten or semi-molten state by the ultra-high speed at the high-temperature heat source and conflicting with a substrate. It is desirable to melt completely the thermal spray powder in order to produce the coating layer with an optimal adhesion, however, because a semi-molten powder in a spray process has the low efficiency and become a factor that degrades the mechanical property by the inducement of pore-forming within the coating layer. To improve the wear resistance, corrosion resistance and heat resistance, in this study, the plungers of high-speed and ultra-high pressure reciprocating hydraulic pumps for oil and water used in ironwork are produced with $420J_2$ and the coating layers of plungers are formed by the powders of WC-Co-Cr and WC-Cr-Ni including the high hardness WC. The surface of these plungers is modified by the super-mirror face grinding machine using variable air pressure developed in this laboratory, and then the characteristics of cross-sectional microstructure, and surface roughness and hardness values between no operation and 100 days-operation are examined and made a comparison. The fine tops and bottoms on surface roughness curve of oil-hydraulic pump plunger sprayed by WC-Cr-Ni are molded more and higher than those of water-hydraulic pump sprayed by WC-Co-Cr because the plunger diameter of oil-hydraulic pump is 0.4 times smaller than that of water-hydraulic pump and the pressure of oil-hydraulic pump exerted on the plunger is operated with the 70 bars higher than that of water-hydraulic pump. As a result, it is found that the values of centerline average surface roughness and maximum height for oil-hydraulic pump plunger are bigger than those of water-hydraulic pump plunger.

• 한국유체기계학회 논문집
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• 제6권2호
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• pp.29-33
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• 2003

The periphery pump (or regenerative pump) has been generally applied in the automotive fuel pump due to their low specific speed (high heads and small flow rate) with stable performance curves. In this study, the performance prediction of side channel type periphery pumps has been developed. The prediction of the circulatory flow rate is based on the consideration of the centrifugal force field in the side-channel and in the impeller vane grooves. For the determination of performance curve (head-flow rate), momentum exchange theory is used. The effects of various geometric parameters and loss coefficients used in the performance prediction method on the head and efficiency are discussed, and the results were compared with experimental data.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.581-584
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• 2002

The periphery pump(or regenerative pump) has been generally applied in the automotive fuel pump due to their low specific speed(high heads and small flow rate) with stable performance curves. In this study, the performance prediction of side channel type periphery pumps has been developed. The prediction of the circulatory flow rate is based on the consideration of the centrifugal force field in the side-channel and in the impeller vane grooves. For the determination of performance curve(head-flow rate), momentum exchange theory is used. The effects of various geometric parameters and loss coefficients used in the performance prediction method on the head and efficiency are discussed and the results were compared with experimental data.