DCV 42 PX - MapleSim Help

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DCV 42 PX

4-way 2-position parallel-cross directional control valve

 

Description

Connections

Parameters

Description

The DCV 42 PX component is a 4-way 2-position valve. The area between pairs of ports varies as a function of the spool input signal, s, and the parameters Amax, Amin, and band. The following table gives the areas for two values of the spool input.

Spool Input

P-A

P-B

A-T

B-T

0

Amax

Amin

Amin

Amax

1

Amin

Amax

Amax

Amin

Transitions are centered at the midpoint, with the width given by the band parameter, as shown in the following diagram.

Formulation Approaches

Two approaches were taken for formulation of the flow equation inside the device. When the boolean parameter Use constant Cd is true, a constant coefficient of discharge (Cd) is used, otherwise a variable coefficient of discharge with maximum value (Cdmax) and a critical flow number (Critno) are used.

Optional Volumes

The boolean parameters Use volume A, Use volume B, Use volume P, and Use volume T, when true, add optional volumes VA, VB, VP, and VT to ports A, B, P, and T, respectively. See Port Volumes for details.

If two orifices or valves are connected, enabling a volume at the common port reduces the stiffness of the system and improves the solvability.

Connections

Name

Description

Modelica ID

portA

Hydraulic port A

portA

portB

Hydraulic port B

portB

portP

Hydraulic port P (pump)

portP

portT

Hydraulic port T (tank)

portT

s

Spool input signal

s

Parameters

General

Name

Default

Units

Description

Modelica ID

Amax

1·10−4

m2

Maximum orifice opening area; available when use scales is true

Amax

Amin

1·10−12

m2

Minimum orifice opening area (leakage)

Amin

band

0.1

 

Transition length in normalized spool displacement units

band

Orifice

Name

Default

Units

Description

Modelica ID

Use constant Cd

true

 

True (checked) means a constant coefficient of discharge is implemented, otherwise a variable Cd is used in flow calculation

UseConstantCd

Cd

0.7

 

Flow-discharge coefficient; used when Use constant Cd is true

Cd

Cr

12

 

Reynolds number at critical flow; used when Use constant Cd is true

ReCr

Cdmax

0.7

 

Maximum flow-discharge coefficient; used when Use constant Cd is false

Cd_max

Critno

1000

 

Critical flow number; used when Use constant Cd is false

Crit_no

Optional Volumes

X corresponds to ports A, B, P, and T.

Name

Default

Units

Description

Modelica ID

Use volume X

false

 

True (checked) means a hydraulic volume chamber is added to portX

useVolumeX

VX

1·10−6

m3

Volume of chamber attached to portX

Vx

For more information see Port Volumes.

See Also

Directional Control Valves

Hydraulics Library