• 동력기계공학회지
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• 제17권6호
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• pp.5-10
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• 2013

Diesel engines have the advantages of good fuel efficiency and low emissions. Therefore, car makers have been developed various kinds of diesel engine management system to clean up emissions while improving fuel efficiency. One of them is the common rail system. In the common rail system, diesel fuel is injected into the combustion chamber at ultra high pressures up to 1,800 bar to ensure more complete combustion for cleaner exhaust gas, and highly precise multiple injection reduces NOx emission, combustion noise and vibration. Generally speaking, common rail system consists of booster pump, high pressure pump, common rail, injectors, control valves, and sensors. The high pressure pump receives low pressure fuel from the booster pump and supply high pressure fuel to injectors through the high pressure common injection rail. Therefore, high pressure pump has an important role in common rail system. In this paper, we have investigated the performance of high pressure pump of common rail system.

• Journal of Mechanical Science and Technology
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• 제20권10호
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• pp.1626-1637
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• 2006

The pressure pulsation due to the gear geometry of the gerotor (generalized rotor) pump mainly occurs in an instant that the chamber of the gerotor enters the delivery port and leaves the suction one. Such a pressure pulsation may result in undesirable vibration and noise of pump components as well as cavitation in hydraulic system. Therefore, it is very important to examine the pressure characteristic of the gerotor pump at its design and analysis stages. In this paper, in order to reduce the pressure pulsation in the gerotor pump, the port plate with the relief grooves is designed by referring to as notch of vane pump and relief groove of piston pump. A series of the theoretical analyses on the pressure pulsation is performed in consideration of various design parameters of the port plate, including the installation positions of the port inlet/outlet and the groove width, and the operating conditions such as rotational velocity and delivery pressure.

• 동력기계공학회지
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• 제18권6호
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• pp.51-57
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• 2014

High pressure common rail injection technology has revolutionized the diesel industry. Over the last decade it has allowed engine builders to run higher injection pressures as much as above 1,300bar in order to increase engine efficiency, while reducing emissions. This common rail system has low pressure circuit which is consist of low pressure pump, cascade overflow valve and flow metering unit. The low pressure pump's purpose is to feed fuel oil to the high pressure pump. The cascade overflow valve keeps pressure in front of the metering unit constant and provides lubrication for the high pressure pump. The metering unit, known as the MPROP or fuel pressure regulator, regulates the maximum flow rate delivers to the rail. In this paper, we have investigated the performance characteristics of each components and total low pressure circuit of common rail system.

• 유공압시스템학회:학술대회논문집
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• 유공압시스템학회 2010년도 춘계학술대회
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• pp.33-38
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• 2010

As for an oil hydraulic vane pump of vehicle hydraulic systems, the highest of planning technique required by the acquisition of optimum profile data which can be available to predict noises and vibrations. Pressure pulsation may result in considerable vibration and noise of pump component as well as cavitation in hydraulic system. The influences of the discharge pressure and rotating speed of the vane on the dynamic pressure in chamber surrounding a vane have been investigated. It is very important to predict pressure pulsation in vane pump. This paper presents analysis of technique of vane pump for automatic transmission. The predicted result using AMESim model were good agreement with the experimentally obtained results.

• 융복합기술연구소 논문집
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• 제4권2호
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• pp.61-65
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• 2014

Pressure distribution around rotating impeller blades in centrifugal pump has been main issue for design of efficient and high performance automotive water pump. In addition, pressure losses of inlet water pipes should be considered to reduce additional pressure drop and design high performance engine cooling system. In this paper, pressure distribution inside water pump and pressure drop between inlet and outlet of water pump are investigated numerically to design plastic water pump for clean diesel engine application. And the inlet geometry of water pump was considered to analysis the effect of inlet water pipe geometry on pressure distribution around impeller blades and outlet pressure. The prediction results are compared with experimental data to validate and determine optimal operation condition without water pump cavitation. Major design parameters such as blade angle, volute geometry, system pressure, and coolant flow rate are considered to confirm applying possibility of plastic blades to the clean diesel engine.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.208-210
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• 2007

This paper proposes a novel direct instantaneous pressure control(DIPC) of hydraulic pump system with SR drive. And it has very simple control structure, because it doesn’t use any speed and torque control for adjusting pump pressure. The hysteresis band of pressure and proper switching rules can make the actual pump pressure to be constant with fast dynamic response. Therefore, the proposed DIPC method can control of hydraulic pump pressure steadily with fast dynamic response.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.359-364
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• 2005

Centrifugal pump shows the strongest secondary flow. Wake is formed near pressure surface close to hub at impeller exit for centrifugal pump impeller. Pressure gradient drives secondary flow in the inducer region, while in the remaining region the following sources drive together: > Pressure gradient > Coriolis force Low-momentum fluid near suction surface hub moves toward pressure surface hub in mixed-flow pump impeller. Tip leakage vortex dominate secondary flow in axial-flow pump impeller. Tip leakage vortex dominate secondary flow in axial-flow in axial-flow pump impeller

• 한국자동차공학회논문집
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• 제12권2호
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• pp.109-116
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• 2004

Bent-axis piston pump have been commonly used in hydraulic systems because of high pressure level, best efficiency, low shear force on pistons and low operating costs. The other side, they have a few demerits like that they have the relatively high number of moving parts and more discharge pressure ripples. Especially, the discharge pressure ripples bring about vibrations and noises in hydraulic system components such as connecting pipes and control valves, so that these deteriorate the stability and accuracy of the systems. Therefore, the hydraulic systems having the bent-axis piston pump require the methods to reduce the discharge pressure ripples. So, the purpose of this paper is to reduce the discharge pressure ripples by the phase interference of pressure wave and to develope the analysis model of the pumps to predict the discharge pressure ripples. In this paper, the analysis model of the bent-axis piston pump was developed using the AMESim software, and the reliability of that was verified by the comparison with the experimental results. The hydraulic pipeline with a parallel line was used as the method to generate the phase interference of pressure wave. the dynamics characteristics of the hydraulic pipeline with a parallel line were analyzed by a transfer matrix method. the usefulness of the phase interference of pressure wave was investigated through the experiment and simulation. The results from the experiment and simulation said that the phase interference of pressure wave by the hydraulic pipeline with a parallel line could reduce the discharge pressure wave of the pump well. The analysis model of the bent-axis piston pump developed in this paper and the method of the phase interference by the hydraulic pipeline with a parallel line are expected to be helpful to achieve the design of the pump and to reduce the discharge pressure wave of the pump effectively.

• Tribology and Lubricants
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• 제14권1호
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• pp.79-84
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• 1998

This paper presents the experimental study of the dynamic internal pressure within a vane pump. The measurement of the dynamic internal pressure acting on the line contact between the vane and the camring in a vane pump with intravanes have been investigated. The variations of the radial acting force of a vane are calculated from previously measured results of dynamic internal pressure in four chambers surrounding a vane, and the variations of the film thickness are estimated in both the rotational speed ranges from 600 to 1200 rpm and the delivery pressure ranges from 1 to 14 MPa. The experimental technic has been established to obtain the data for performance analysis, such as reaction forces between vane and camring, friction wear at the contact regions, leakage characteristics and net forces upon the pump shaft in case of the unsteady load which is forced to the intravane pressure balance type vane pump.

• 드라이브 ㆍ 컨트롤
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• 제11권4호
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• pp.53-60
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• 2014

This paper proposes a control scheme to reduce the power consumption of a variable displacement swash-plate type piston pump supplying oil to a valve-controlled hydraulic cylinder at constant pressure. Whenever flow rate demand was absent, the swash plate angle and the pump speed were changed to the minimum values required to compensate for the internal leakage flow. In response to command signals, the pump speed was changed in proportion to the absolute mean value of the speed component for position commands. At the same time, a pressure regulator was activated to maintain constant system pressure by precisely adjusting the pump speed with the swash plate angle fixed at the maximum. The conventional system consisting of a pressure-compensated variable displacement type pump is driven at a constant speed of 1,800rpm. By comparison, computer simulation and experimental results showed that idling power at stand-by status could be reduced by up to 70% by reducing the pump speed from 1,800rpm to 300rpm and the swash plate angle to the minimum.