fourthreewaydirectionalvalve

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fourthreewaydirectionalvalve

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Iconic Diagrams\Hydraulics\Valves\Basic Valves

Use

Domains: Continuous. Size: 1-D. Kind: Iconic Diagrams (Hydraulics).

Description

This model is equal to the four three way proportional valve model, except for the spool position. The spool position is rounded to 0, 1 or -1:

 

-0.5 < spoolpos < 0.5 => pos = 0

spoolpos >= 0.5 => pos = 1

spoolpos <= -0.5 => pos = -1

 

The spool dynamics is modeled by a second order transfer function:

 

sp = SO(f,d,discrete(pos))

 

which is characterized by the bandwidth (f) and damping (d).

Implementation

The 4/3-way directional control valve is implemented with various spool centre configurations. The configurations are shown in the picture below:

SpoolCenters

When you drag and drop a model in the editor, you will be asked which implementation you want to choose. During modeling you can easily change the spool center configuration:

1.Select the valve model.
2.Click the right mouse button to open the right mouse menu.
3.Click Edit Implementation and choose another implementation.

Interface

Ports

Description

pp, pt, pa, pb,

All terminals of the valve.

Causality

 

fixed volume flow out pp

fixed volume flow out pt

fixed volume flow out pa

fixed volume flow out pb

 

Inputs

 

spoolpos

position of the spool valve: 0 =closed, 1 = open

0 <= spoolpos <= 1

Parameters

 

rho

GLeak

Amax

Cd

overlap

f

d

Mass density of the fluid [kg/m3].

Conductance of the laminar leakage flows [m3/s.Pa], GLeak >= 0.

Maximum spool valve areas when the valves are open [m2], Amax > 0.

Discharge coefficient [], Cd > 0.

The valve overlaps in closed position [], -1 < overlap < 1.

Bandwidth of the spool dynamics [Hz], f > 0.

Damping of the spool dynamics [], d > 0