• Journal of Power System Engineering
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• v.15 no.6
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• pp.86-94
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• 2011

In this paper, an electro hydraulic power steering system based on electro hydrostatic actuator (EHA) is proposed. A detailed steering model for the proposed electro hydraulic power steering system including mechanical and hydraulic subsystems is established. A conventional electro hydraulic power steering system is also modeled to evaluate the performance of the proposed power steering system such as responsiveness, assist force, command tracking and steering feel by computer simulation. From the computer simulation results, it is found that the proposed power steering system based on EHA has desirable performance.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1248-1252
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• 1999

To provide electricity power of good quality, it is essential to establish generation of electricity plan in electric power system based on accurate power-demand prediction and cope with changes of power-need fluctuating constantly. The role of hydraulic-power generation of electricity in electric power system is of importance because responding to electric power-demand counts or reservoir-type hydraulic-power generation of electricity which is designed for additional load in electric power system. So hydraulic-power generation of electricity must have fast start reserve. But the amount of water, resources of reservoir-type hydraulic-power generation of electricity is restricted and multi-used, so the scheduling of management by exact forecasting the amount of water is critical. That is why efficient hydraulic-power generation of electricity makes a main role on pumping up the utility of energy and water resource. This thesis introduced the example of optimal generation of electricity plan establishment which is used in managing reservoir-type hydraulic-power generation of electricity.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.168-173
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• 2004

This article describes the design of a hydraulic system for a power split type continuously variable transmission (CVT). The CVT considered here, is composed of planetary gears, clutches, and a torque converter which is mainly used for the realization of CVT function. Similar to automatic transmissions, the hydraulic system of CVT is designed for supplying hydraulic flows and pressures to each component of CVT, in order to activate the clutch engagements and torque converter operation, and to cool the drivetrain. By using the mathematical models of drivetrain, a simulation program was developed to investigate the power performance of CVT equipped vehicle and the operating conditions of each component of CVT. And the design parameters of the hydraulic system and clutches were calculated using the operating conditions and power requirements which obtained from the simulation results. Finally the hydraulic circuit design of prototyped valve body is presented based on the numerical results of this analysis.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.3
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• pp.10-15
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• 2009

The major system of an agricultural power-shift tractor is the transmission, using power-shift. Because the transmission performance depends on the hydraulic control system, the most important aspect of the optimization is the design of the hydraulic control system. This study was conducted to improve a pressure modulation characteristics of the power-shift transmission hydraulic system. It has been tried to replace an existing pressure modulation method with a digital control by using HSSV(High Speed Solenoid Valve). The performance of the PWM control system in power-shift hydraulic transmission has been evaluated by means of experiment.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.4
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• pp.16-23
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• 2009

The major system of an agricultural shuttle power-shift tractor is the transmission, using power-shift. Because the shifting performance depends on the hydraulic control system, the most important aspect of the optimization is the design of the hydraulic control system. This study was conducted to develop the simulation model of hydraulic control system for the shuttle power-shift transmission by using Easy5 software. Bench test was conducted to verify the simulation. Also, the design parameters which influence the pressure modulation characteristics were investigated.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.3
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• pp.305-310
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• 2001

Hydraulic power shifting systems of hydraulic travel motor may be far safer than mechanical power transmission systems. Thus, hydraulic power shifting systems are widely used for speed control on the hydraulic equipments. In the case of liquid shifting lines, the rapid change of area, such as valve closing, can result in a large pressure transient. It is necessary to assure proper control method in order to obtain the smallest shift shock. This study conducts the shock characteristics of hydraulic power shifting system of the hydraulic travel motor. Experimental results show that shock pressure depends on the operating pressure, flow rate and pipe line area. The shock characteristics can be applied for reducing shocks.

• Transactions of The Korea Fluid Power Systems Society
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• v.3 no.3
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• pp.8-13
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• 2006

It is very important for the manufacturers to predict the life of hydraulic system components according to the results of life tests. Since it takes too much time to test the hydraulic system components until failure, the no-failure test method is applied for the life test of them. If the shape parameter of Weibull distribution, the number of samples, the confidence level, and the assurance life are given, the no-failure test times of hydraulic system components can be calculated by given equation. Here, the procedures to obtain the no-failure test times of the hydraulic system components such as hydraulic motors and pumps, hydraulic cylinders, hydraulic valves, hydraulic accumulators, hydraulic hoses, and hydraulic filters are described briefly.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.151-158
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• 2008

The clutch system is a subcomponent of the transmission that is designed to engage and disengage power flow between the engine and the transmission. Recently, the engine power of automobile has been continuously increased because of customer's demand for the bigger one. As the engine power is increased, the vibration transmitted to the hydraulic clutch operating system has been increased. Therefore the demand for the reduction of clutch pedal vibration during the operation has been increased. This paper describes the pressure pulsation reduction characteristics of the damper cylinder which is applied to the hydraulic clutch operating system. And the purpose of this study is to propose an analysis model and investigate the effect of the design variable variations for the hydraulic clutch system. Especially, we studied the effect of damper cylinder parameter variations on the hydraulic clutch system performance.

• Journal of Drive and Control
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• v.18 no.4
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• pp.43-51
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• 2021

In this study, we designed a hydraulic propulsion propeller system that allows dredged materials to be carried out by the dredger to the disposal place. The proposed model equation was used to formulate the screw propeller specifications considering the resistance to the dredger, and the quantitative specifications of the hydraulic propulsion propeller were determined through the numerical analysis programs. In addition, based on the proposed results, we were able to determine the specifications of the hydraulic system that was used for the hydraulic motor in the propulsion propeller device and then manufactured the hydraulic propulsion propeller. To guarantee the reliability of the proposed model equation, an external testing agency was invited and verified that the hydraulic propulsion propeller based on the proposed model equation could achieve the target speed in the dredger.

• Tribology and Lubricants
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• v.20 no.3
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• pp.163-167
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• 2004

Reducing friction torque of the oil hydraulic vane pump used as the power source of power steering system should consider friction torque including viscous and mechanical friction torque according to the changes of rpm and pressure. This paper analyzes the forces acting on the vane to reduce the friction torque of the vane of the hydraulic vane pump used for Hydraulic Power Steering(HPS) system, and futhermore, the forces according to the shapes of cam profiles are analyzed.