A Close-up View of a Load Sensing “Hybrid” Proportional Directional Control Valve

This study presents the static and dynamic characteristics of load-sensing and pressure-compensated directional control valve under the working conditions. A mathematical model is developed, two types of working conditions are presented through the static work point calculation. The static characteristic is analyzed by simulation, and the conclusion is validated by experiments. Solution procedure of the flow gain transfer function and flow-pressure coefficient transfer function is detailed introduced based on the above static computation, and their dynamic characteristic is analyzed by using Bode diagram. Finally, three types of compensatory modes are proposed, which provides very useful value and significance for the hydraulic component or system design and parameters optimization.

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Energy Saving Load-Sensing Hydraulic Drive Based on Multimode Directional Control Valve

Lecture Notes in Mechanical Engineering - Advances in Design, Simulation and Manufacturing IV ◽

10.1007/978-3-030-77823-1_37 ◽

2021 ◽

pp. 371-380

Author(s):

Oleksandr Petrov ◽

Andrii Slabkyi ◽

Leonid Kozlov ◽

Nataliia Rybko

Keyword(s):

Energy Saving ◽

Hydraulic Drive ◽

Control Valve ◽

Load Sensing ◽

Directional Control ◽

Directional Control Valve

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CFD Simulation of a Post-Compensated Load Sensing Directional Control Valve

E3S Web of Conferences ◽

10.1051/e3sconf/202131205002 ◽

2021 ◽

Vol 312 ◽

pp. 05002

Author(s):

Paola Fresia ◽

Massimo Rundo

Keyword(s):

Pressure Drop ◽

Cfd Simulation ◽

Control Valve ◽

Design Tool ◽

Lumped Parameter Model ◽

Cfd Model ◽

Load Sensing ◽

Directional Control ◽

Lumped Parameter ◽

Directional Control Valve

The paper presents the CFD model of a load sensing directional control valve. The model was validated experimentally in terms of pressure drop and flow force at different positions of the spool. The spool position was imposed manually by means of a micrometric screw and a load cell was used for measuring the flow force. The CFD model was developed with the CAD-embedded tool FloEFD®. The model has been proved to be very reliable in estimating the pressure drop, moreover quite good results were obtained also in the evaluation of the flow force. The CFD simulations were used to tune the coefficients of a lumped parameter model of the valve, so that such a model can be efficiently used for the simulation of an entire hydraulic circuit. Moreover, the CFD model has been used as design tool for attenuating the detrimental effect of the flow force. In particular, the width of the land upstream of the metering edge has an influence on the resultant force on the spool. If was found that it is possible to significantly reduce the flow force at maximum opening with a relatively small increment of the pressure drop across the valve.

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Research of stability of Load-sensing hydraulic drive operation, on the base of multimode directional control valve

Journal of Mechanical Engineering and Transport ◽

10.31649/2413-4503-2020-12-2-93-99 ◽

2021 ◽

Vol 12 (2) ◽

pp. 93-99

Author(s):

Oleksandr Petrov ◽

◽

Leonid Kozlov ◽

Natalia Semichastnova ◽

Olha Zavalniuk ◽

...

Keyword(s):

Pressure Drop ◽

Energy Efficient ◽

Hydraulic Drive ◽

Control Valve ◽

Design Parameters ◽

Hydraulic Motor ◽

Load Sensing ◽

Directional Control ◽

The Stability ◽

Directional Control Valve

The article describes a new scheme of a hydraulic drive, which, thanks to the original design of a multimode directional control valve, has energy-efficient properties that are characteristic of load-sensing hydraulic drives. The proposed design of the multimode directional control valve ensures the operation of the hydraulic drive in four modes – unloading the hydraulic pump, regulating the flow of the hydraulic motor, the maximum flow of the hydraulic motor and protection against overload. In each of these modes, the hydraulic drive operates with low power losses due to the presence of a constant balancing pressure drop. This value is formed by a combination of design parameters of the directional control valve. The proposed value of the value of the balancing pressure drop of 0,7-0,8 MPa provides high energy efficiency of the hydraulic drive in the most critical operating mode – regulation of the hydraulic motor flow. In order to ensure the stability of the energy-efficient operation of the hydraulic drive in this mode, a research was made of the stability of transient processes with various combinations of design parameters of the overflow valve of the hydraulic control valve, as well as changes in the operating conditions of the hydraulic drive. As a result of theoretical researches, on the basis of mathematical modeling of working processes, combinations of design parameters of the hydraulic lock and the spool of the overflow valve were identified, which ensure the stability of the hydraulic drive in the mode of regulating the flow of the hydraulic motor. In particular, these are such parameters as the stiffness of the springs of the hydraulic lock and the overflow valve, the diameter and angle of inclination of the edge of the overflow valve spool, the area of the radial holes and the auxiliary choke of the overflow valve. It was also determined that in this mode, the stability of the hydraulic drive will be ensured under conditions of a load pressure of up to 20 MPa, a hydraulic motor flow rate of 100 l / min and a working fluid temperature of 80 °C.

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