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4-Way 2-Position Directional Valve (IL)

4-way, 2-position directional valve in an isothermal liquid network

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  • Simscape / Fluids / Isothermal Liquid / Valves & Orifices / Directional Control Valves

Description

The 4-Way 2-Position Directional Valve (IL) block models a valve with four openings in an isothermal liquid network, typically between an actuator, pump, and tank. The valve operation is controlled by a single spool displaced according to the signal at port S. You can set the baseline configuration of your valve by specifying the orifices that are open when the spool moves in the positive direction and negative directions in the Positive spool position open connections and Negative spool position open connections parameters, respectively.

You can set the model for valve opening in the Orifice parameterization parameter as a linear relationship or function of user-provided data, which can be applied to one or all flow paths in the valve.

In some configurations, this valve resembles a 3-way valve. To set additional flow paths when the spool is in the neutral position, see the 4-Way 3-Position Directional Valve (IL) block.

Example Valve Setup

In this configuration, Negative spool position open connections is set to P-A and B-T. When the signal at port S moves the spool to a negative position, the paths between ports P and A and between ports B and T are open to flow. The paths between ports P and B and ports A and T are closed to flow:

In this configuration, Positive spool position open connections is set to P-B and A-T. When the signal at port S moves the spool to a positive position, the paths between ports P and B and between ports A and T are open to flow and the paths between ports P and A and between ports B and T are closed:

Schematically, this configuration is:

The left-hand side corresponds to the positive position and the right-hand side corresponds to the negative position. The valve transitions through positions in the neutral mid-section.

Spool Displacement and Valve Configuration

The spool stroke is the amount of spool travel an orifice takes to fully open from a closed position and is defined for each orifice selected on the Valve Configuration tab. The table below shows how the stroke is calculated in accordance with the valve orifice parameterization and flow path characteristics.

Spool Stroke Based on Parameterization and Flow Path

Orifice ParameterizationIdentical for All Flow PathsDifferent for Each Flow Path
Linear - Area vs. spool travelDefined by the Spool travel between closed and open orifice parameterDefined by the Spool travel between closed and open orifice parameter, for each orifice
Tabulated data - Area vs. spool travelThe difference between the first and last element of the Spool travel vector parameterThe difference between the first and last element of the spool travel vector parameter for each orifice
Tabulated data - Volumetric flow rate vs. spool travel and pressure dropThe difference between the first and last element of the Spool travel vector, ds parameterThe difference between the first and last element of the spool travel vector, ds parameter for each orifice

To see the orientation of all valve orifices, see the Visualize Orifice Openings section.

The direction of spool movement signaled at port S depends on the spool stroke and the orifice orientation:

Orifice Definition and Spool Travel Direction

Spool Position when Orifice is OpenSpool Travel, ΔS
Always closed (orifice is not selected in any spool position configuration)N/A
Always open (orifice is selected in positive, neutral, and negative spool position configurations)N/A
NegativeSorifice_max + spool stroke – S
PositiveSorifice_max + spool stroke + S

Where Sorifice_max is the spool position at the maximum orifice area defined for each orifice.

The possible configurations of the 4-Way 2-Position Directional Valve (IL) block are shown below.

4-Way 2-Position Directional Valve Configuration

ConfigurationParameter Values

All four paths are closed during transition.

  • Positive spool position open connections: P-A and B-T

  • Negative spool position open connections: P-B and A-T

  • Spool position at maximum P-A orifice area > P-A spool stroke

  • Spool position at maximum P-B orifice area < –P-B spool stroke

  • Spool position at maximum A-T orifice area < –A-T spool stroke

  • Spool position at maximum B-T orifice area > B-T spool stroke

All four paths are open during transition.

  • Positive spool position open connections: P-A and B-T

  • Negative spool position open connections: P-B and A-T

  • Spool position at maximum P-A orifice area < P-A spool stroke

  • Spool position at maximum P-B orifice area > –P-B spool stroke

  • Spool position at maximum A-T orifice area > –A-T spool stroke

  • Spool position at maximum B-T orifice area < B-T spool stroke

A-T and B-T are closed during transition.

  • Positive spool position open connections: P-A and B-T

  • Negative spool position open connections: P-B and A-T

  • Spool position at maximum P-A orifice area < P-A spool stroke

  • Spool position at maximum P-B orifice area > –P-B spool stroke

  • Spool position at maximum A-T orifice area < –A-T spool stroke

  • Spool position at maximum B-T orifice area > B-T spool stroke

P-A and P-B are closed during transition.

  • Positive spool position open connections: P-A only

  • Negative spool position open connections: P-B only

  • Spool position at maximum P-A orifice area > P-A spool stroke

  • Spool position at maximum P-B orifice area < –P-B spool stroke

P-B and B-T are closed during transition.

  • Positive spool position open connections: P-B and A-T

  • Negative spool position open connections: P-A and B-T

  • Spool position at maximum P-A orifice area < P-A spool stroke

  • Spool position at maximum P-B orifice area > P-B spool stroke

  • Spool position at maximum A-T orifice area > A-T spool stroke

  • Spool position at maximum B-T orifice area < –B-T spool stroke

P-A and A-T are closed during transition.

  • Positive spool position open connections: P-B and A-T

  • Negative spool position open connections: P-A and B-T

  • Spool position at maximum P-A orifice area < –P-A spool stroke

  • Spool position at maximum P-B orifice area < P-B spool stroke

  • Spool position at maximum A-T orifice area > A-T spool stroke

  • Spool position at maximum B-T orifice area > –B-T spool stroke

P-A, P-B, and B-T are open during transition.

  • Positive spool position open connections: P-A and P-B

  • Negative spool position open connections: P-A and B-T

  • Spool position at maximum P-A orifice area < P-A spool stroke

  • Spool position at maximum P-B orifice area < P-B spool stroke

  • Spool position at maximum A-T orifice area = any value

  • Spool position at maximum B-T orifice area > –B-T spool stroke

P-A, A-T, and B-T are open during transition.

  • Positive spool position open connections: P-B and A-T

  • Negative spool position open connections: P-A and P-B

  • Spool position at maximum P-A orifice area > –P-A spool stroke

  • Spool position at maximum A-T orifice area < A-T spool stroke

  • Spool position at maximum B-T orifice area = any value

P-A and P-B are closed during transition. A-T is always closed.

  • Positive spool position open connections: P-A and P-B

  • Negative spool position open connections: P-A and B-T

  • Spool position at maximum P-B orifice area > P-B spool stroke

  • Spool position at maximum B-T orifice area < –B-T spool stroke

All paths are closed during transition.

  • Positive spool position open connections: P-B and A-T

  • Negative spool position open connections: P-A and P-B

  • Spool position at maximum P-A orifice area < –P-A spool stroke

  • Spool position at maximum P-B orifice area > P-B spool stroke

  • Spool position at maximum A-T orifice area > A-T spool stroke

A-T is open during transition. P-A is closed during transition.

  • Positive spool position open connections: P-A and P-B

  • Negative spool position open connections: P-A and B-T

  • Spool position at maximum P-A orifice area > P-A spool stroke

  • Spool position at maximum P-B orifice area > P-B spool stroke

  • Spool position at maximum A-T orifice area = any value

  • Spool position at maximum B-T orifice area > –B-T spool stroke

B-T is open during transition. P-B is closed during transition.

  • Positive spool position open connections: P-B and A-T

  • Negative spool position open connections: P-A and P-B

  • Spool position at maximum P-A orifice area < –P-A spool stroke

  • Spool position at maximum P-B orifice area > P-B spool stroke

  • Spool position at maximum A-T orifice area < A-T spool stroke

  • Spool position at maximum B-T orifice area = any value

P-A is closed during transition.

  • Positive spool position open connections: P-A and B-T

  • Negative spool position open connections: P-A and P-B

  • Spool position at maximum P-A orifice area > P-A spool stroke

  • Spool position at maximum P-B orifice area < –P-B spool stroke

  • Spool position at maximum B-T orifice area > B-T spool stroke

P-B is closed during transition.

  • Positive spool position open connections: P-A and P-B

  • Negative spool position open connections: P-B and A-T

  • Spool position at maximum P-A orifice area > P-A spool stroke

  • Spool position at maximum P-B orifice area > P-B spool stroke

  • Spool position at maximum A-T orifice area > –A-T spool stroke

Valve Orifice Parameterizations

The Orifice parameterization parameter sets the model for the open area or volumetric flow rate through one or all of the valve orifices. If you set Area characteristics to Identical for all flow paths, the block applies the same data for all flow paths; otherwise, individual parameterizations are applied for the Different for all flow paths setting. You can model valve opening in three ways:

  • Linear - area vs. spool travel

    The opening area is a linear function of the spool position received as a signal at port S:

    Aorifice=(AmaxAleak)ΔSmaxΔS+Aleak,

    where:

  • Tabulated data - Area vs. spool travel

    Provide spool travel vectors for your system or for individual flow paths between ports P, A, B, and T. This data will be used to calculate the relationship between the orifice area and spool displacement. Interpolation is used to determine the opening area between given data points. Aleak and Amax are the first and last parameters of the opening area vector, respectively.

  • Tabulated data - Volumetric flow rate vs. spool travel and pressure drop

    Provide spool travel and pressure drop vectors and a dependent, 2-D volumetric flow rate array. Interpolation is used to determine flow rate between given data points. The mass flow rate is the product of the volumetric flow rate and the local density.

Numerically-Smoothed Valve Area in the Linear Parameterization

When the valve is in a near-open or near-closed position in the linear parameterization, you can maintain numerical robustness in your simulation by adjusting the block Smoothing factor. A smoothing function is applied to all calculated areas, but primarily influences the simulation at the extremes of the valve area.

The normalized valve area is calculated as:

A^=(AorificeAleak)(AmaxAleak).

The Smoothing factor, s, is applied to the normalized area:

A^smoothed=12+12A^2+(s4)212(A^1)2+(s4)2.

The smoothed valve area is:

Asmoothed=A^smoothed(AmaxAleak)+Aleak.

Visualize Orifice Openings

To visualize spool offsets and maximum displacement, right-click on the block and select Fluids > Plot Valve Characteristics. The plot shows the orifices selected in the Valve Configuration tab settings. The axes are set by the orifice parameterization selection and are either:

  • Orifice Area vs. Spool Position

  • Volumetric Flow Rate vs. Spool Position, queried at a specific pressure differential

When the positive and negative settings in the Valve Configuration tab feature the same orifice, the orifice opening is displayed as a constant.

Each time you modify the block settings, click Apply at the bottom of the dialog box, then click Reload Data on the figure window.

The image below shows the valve default configuration. On the Valve Configuration tab:

  • Positive spool position open connections is set to P-A and B-T.

  • Negative spool position open connections is set to P-B and A-T.

All other spool positions are at the default values.

Example Spool Position Visualization

Faulty Behavior

When faults are enabled, the valve open area becomes stuck at a specified spool position in response to one of these triggers:

  • Simulation time — Faulting occurs at a specified time.

  • Simulation behavior — Faulting occurs in response to an external trigger. This exposes port Tr.

Four fault options are available in the Spool position when faulted parameter:

  • Positive — The spool position freezes in the positive position, opening the Positive spool position open connections flow paths to their maximum value. The flow paths that are only open in the Negative spool position open connections and Neutral spool position open connections are closed.

  • Negative — The spool position freezes in the negative position, opening the Negative spool position open connections flow paths to their maximum value. The flow paths that are only open in the Positive spool position open connections and Neutral spool position open connections are closed.

  • Maintain last value — The valve freezes at the spool position when the trigger occurs.

Due to numerical smoothing at the extremes of the valve area, in the linear parameterization, the minimum area applied is larger than the Leakage area, and the maximum is smaller than the Maximum orifice area, in proportion to the Smoothing factor value.

Once triggered, the valve remains at the faulted area for the rest of the simulation.

Predefined Parameterization

Pre-parameterization of the 4-Way 2-Position Directional Valve (IL) block with manufacturer data is available. This data allows you to model a specific supplier component.

To load a predefined parameterization,

  1. Click the "Select a predefined parameterization" hyperlink in the 4-Way 2-Position Directional Valve (IL) block dialog description.

  2. Select a part from the drop-down menu and click Update block with selected part.

  3. If you change any parameter settings after loading a parameterization, you can check your changes by clicking Compare block settings with selected part. Any difference in settings between the block and pre-defined parameterization will display in the MATLAB command window.

Note that it is not possible to set different values for the same orifice for both positive and negative displacement of the control member. Additionally, the opening area is mirrored around the neutral position.

Note

Predefined parameterizations of Simscape components use available data sources for supplying parameter values. Engineering judgement and simplifying assumptions are used to fill in for missing data. As a result, deviations between simulated and actual physical behavior should be expected. To ensure requisite accuracy, you should validate simulated behavior against experimental data and refine component models as necessary.

Ports

Conserving

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Liquid entry or exit port to the valve.

Liquid entry or exit port to the valve.

Liquid entry or exit port to the valve.

Liquid entry or exit port to the valve.

Input

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Spool displacement, in m, specified as a physical signal.

Physical signal port for an external fault trigger. Triggering occurs when the value is greater than 0.5. There is no unit associated with the trigger value.

Dependencies

This port is visible when Enable faults is set to On and Fault trigger is set to External.

Parameters

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Valve Configuration

Flow paths open when the spool is in a positive position. This parameter sets the valve configuration and defines the direction of spool movement according to the signal received at port S.

Flow paths open when the spool moves in the negative direction. This parameter sets the valve configuration and defines the direction of spool movement according to the signal received at port S.

Model Parameterization

Applies uniform or individual flow equations for the valve orifice area. Identical for all flow paths uses the same orifice and spool geometries, flow rates, pressure, and area vectors for all valve orifices. When using Different for each flow path, these parameters are specified individually for each orifice. In both cases, orifices A, B, P, and T have the same cross-sectional areas, discharge coefficients, and Reynolds numbers in the Linear - Area vs. spool travel and Tabulated data - Area vs. spool travel parameterizations. The same Orifice parameterization is applied to all flow paths.

Method of calculating the valve opening area. In the tabulated data parameterizations, you can provide your own valve area and spool travel data for nonlinear valve opening profiles, or you can provide data in terms of volumetric flow rate, spool travel, and pressure drop over the flow path.

Maximum distance of spool travel.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Linear - Area vs. spool travel.

Largest open area of each orifice during the operation of the valve.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Linear - Area vs. spool travel.

Open area when an orifice is fully closed. Any area smaller than this value is maintained at the specified leakage area. This parameter contributes to numerical stability by maintaining continuity in the flow.

Dependencies

To enable this parameter, set Orifice parameterization to Linear - Area vs. spool travel.

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the Orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Area vs. spool travel.

Vector of opening areas for the tabular parameterization of valve opening area. The vector elements must correspond one-to-one with the elements in the Spool travel vector parameter. The elements are listed in ascending order and must be greater than 0.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Area vs. spool travel.

Vector of spool travel distances for the tabular parametrization of volumetric flow rate. The spool travel vector forms an independent axis with the Pressure drop vector, dp parameter for the 2-D dependent Volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

Vector of pressure drop values for the tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the Spool travel vector, ds parameter for the 2-D dependent Volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

  • M is the number of vector elements in the Pressure drop vector, dp parameter.

  • N is the number of vector elements in the Spool travel vector, ds parameter.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

Orifice area when the positive and negative spool positions feature the same orifice.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to either:

  • Linear - area vs. spool travel.

  • Tabulated data - Area vs. spool travel

The same orifice must be selected in both of the Valve Configuration parameters:

  • Positive spool position open connections

  • Negative spool position open connections

Vector of pressure differential values over the valve when the positive and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

The same orifice must be selected in both of the Valve Configuration parameters:

  • Positive spool position open connections

  • Negative spool position open connections

Vector of volumetric flow rate values for a constant orifice when the positive and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the Constant orifice pressure drop vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

The same orifice must be selected in both of the Valve Configuration parameters:

  • Positive spool position open connections

  • Negative spool position open connections

Maximum cross-sectional areas at the entry and exit ports P, T, A, and B, which are used in the pressure-flow rate equation that determines the mass flow rate through the valve.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to either:

  • Linear - area vs. spool travel

  • Tabulated data - Area vs. spool travel

Correction factor that accounts for discharge losses in theoretical flows.

Dependencies

To enable this parameter, set Orifice parameterization to either:

  • Linear - Area vs. spool travel

  • Tabulated data - Area vs. spool travel

Upper Reynolds number limit for laminar flow through the orifice.

Dependencies

To enable this parameter, set Orifice parameterization to:

  • Linear - area vs. spool travel

  • Tabulated data - Area vs. spool travel

Continuous smoothing factor that introduces a layer of gradual change based to the flow response when the valve is in near-open and near-closed positions. To increase the stability of your simulation in these regimes, set this parameter to a nonzero value less than one.

Dependencies

To enable this parameter, set Orifice parametrization to Linear - area vs. spool travel.

Whether to account for pressure increase when fluid flows from a region of smaller cross-sectional area to a region of larger cross-sectional area.

Dependencies

To enable this parameter, set Orifice parameterization to:

  • Linear - area vs. spool travel

  • Tabulated data - Area vs. spool travel

P-A Orifice

Spool offset from the neutral position for a fully open P-A orifice. To visualize the defined offsets, see Visualize Orifice Openings.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

  • P-A and B-T

  • P-A and P-B

  • P-A only

Negative spool position open connections to:

  • P-A and B-T

  • P-A and P-B

  • P-A only

Note:

This parameter is enabled only when the P-A orifice settings do not appear in both spool position parameters: Positive spool position open connections and Negative spool position open connections.

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Linear - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

    Negative spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

Largest open area of the P-A orifice during the operation of the valve.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Linear - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

    Negative spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the P-A orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

    Negative spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

Vector of opening areas for the tabular parameterization of valve opening area. The vector elements must correspond one-to-one with the elements in the P-A spool travel vector parameter. The elements are listed in ascending order and must be greater than 0.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

    Negative spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

Vector of spool travel distances for the tabular parameterization of volumetric flow rates. The spool travel vector forms an independent axis with the P-A orifice pressure drop vector, dp parameter for the 2-D dependent P-A orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

    Negative spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

Vector of pressure drop values for the tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the P-A orifice spool travel vector, ds parameter for the 2-D dependent P-A orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

    Negative spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

  • M is the number of vector elements in the P-A orifice pressure drop vector, dp parameter.

  • N is the number of vector elements in the P-A orifice spool travel vector, ds parameter.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

    Negative spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

Orifice area when the positive and negative spool positions feature the same orifice.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to either:

    • Linear - area vs. spool travel

    • Tabulated data - Area vs. spool travel

  3. One of the following settings in each parameter:

    Positive spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

    Negative spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

Vector of pressure differential values over the valve when the positive and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the P-A Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following settings in each parameter:

    Positive spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

    Negative spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

Vector of pressure differential values over the valve when the positive and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the P-A Constant orifice pressure drop vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following settings in each parameter:

    Positive spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

    Negative spool position open connections to:

    • P-A and B-T

    • P-A and P-B

    • P-A only

P-B Orifice

Spool offset from the neutral position for a fully open P-B orifice. To visualize the defined offsets, see Visualize Orifice Openings.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

  • P-B and A-T

  • P-A and P-B

  • P-B only

Negative spool position open connections to:

  • P-B and A-T

  • P-A and P-B

  • P-B only

Note:

This parameter is enabled only when the P-B orifice settings do not appear in both spool position parameters: Positive spool position open connections and Negative spool position open connections.

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Linear - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

    or set Negative spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

Largest open area of the P-B orifice during the operation of the valve.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Linear - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

    Negative spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the P-B orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

    Negative spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

Vector of opening areas for the tabular parameterization of valve opening area. The vector elements must correspond one-to-one with the elements in the P-B spool travel vector parameter. The elements are listed in ascending order and must be greater than 0.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

    Negative spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

Vector of spool travel distances for the tabular parameterization of volumetric flow rates. The spool travel vector forms an independent axis with the P-T orifice pressure drop vector, dp parameter for the 2-D dependent P-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

    Negative spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

Vector of pressure drop values for tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the P-B orifice spool travel vector, ds parameter for the 2-D dependent P-B orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

    Negative spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

  • M is the number of vector elements in the P-B orifice pressure drop vector, dp parameter.

  • N is the number of vector elements in the P-B orifice spool travel vector, ds parameter.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

    Negative spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

Orifice area when the positive and negative spool positions feature the same orifice.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to either:

    • Linear - area vs. spool travel

    • Tabulated data - Area vs. spool travel

  3. One of the following settings in each parameter:

    Positive spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

    Negative spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

Vector of pressure differential values over the valve when the positive and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the P-B Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following settings in each parameter:

    Positive spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

    Negative spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

Vector of volumetric flow rate values over the valve when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the P-B Constant orifice pressure drop vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following settings in each parameter:

    Positive spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

    Negative spool position open connections to:

    • P-B and A-T

    • P-A and P-B

    • P-B only

A-T Orifice

Spool offset from the neutral position for a fully open A-T orifice. To visualize the defined offsets, see Visualize Orifice Openings.

Dependencies

To enable this parameter, set one of the following parameters:

  • Positive spool position open connections to P-B and A-T.

  • Negative spool position open connections to P-B and A-T.

Note:

This parameter is enabled only when the A-T orifice settings do not appear in both spool position parameters: Positive spool position open connections and Negative spool position open connections.

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Linear - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to P-B and A-T

    Negative spool position open connections to P-B and A-T.

Largest open area of the A-T orifice during the operation of the valve.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Linear - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to P-B and A-T

    Negative spool position open connections to P-B and A-T.

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the A-T orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to P-B and A-T.

    Negative spool position open connections to P-B and A-T.

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the A-T orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to P-B and A-T.

    Negative spool position open connections to P-B and A-T.

Vector of spool travel distances for the tabular parameterization of volumetric flow rates. The spool travel vector forms an independent axis with the A-T orifice pressure drop vector, dp parameter for the 2-D dependent A-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to P-B and A-T.

    Negative spool position open connections to P-B and A-T.

Vector of pressure drop values for tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the A-T orifice spool travel vector, ds parameter for the 2-D dependent A-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to P-B and A-T.

    Negative spool position open connections to P-B and A-T.

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

  • M is the number of vector elements in the A-T orifice pressure drop vector, dp parameter.

  • N is the number of vector elements in the A-T orifice spool travel vector, ds parameter.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to P-B and A-T.

    Negative spool position open connections to P-B and A-T.

Orifice area when the positive and negative spool positions feature the same orifice.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to either:

    • Linear - area vs. spool travel

    • Tabulated data - Area vs. spool travel

  3. One of the following settings in each parameter:

    Positive spool position open connections to P-B and A-T.

    Negative spool position open connections to P-B and A-T.

Vector of pressure differential values over the valve when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the A-T Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following settings in each parameter:

    Positive spool position open connections to P-B and A-T.

    Negative spool position open connections to P-B and A-T.

Vector of volumetric flow rate values when the positive, neutral, and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following settings in each parameter:

    Positive spool position open connections to P-B and A-T.

    Negative spool position open connections to P-B and A-T.

B-T Orifice

Spool offset from the neutral position for a fully open B-T orifice. To visualize the defined offsets, see Visualize Orifice Openings.

Dependencies

To enable this parameter, set one of the following parameters:

  • Positive spool position open connections to P-A and B-T.

  • Negative spool position open connections to P-A and B-T.

Note:

This parameter is enabled only when the B-T orifice settings do not appear in both spool position parameters: Positive spool position open connections and Negative spool position open connections.

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Linear - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to P-A and B-T.

    Negative spool position open connections to P-A and B-T.

Largest open area of the B-T orifice during the operation of the valve.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Linear - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to P-A and B-T.

    Negative spool position open connections to P-A and B-T.

Vector of spool travel distances for the tabular parameterization of valve area. The vector elements must correspond one-to-one with the elements in the B-T orifice area vector parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to P-A and B-T.

    Negative spool position open connections to P-A and B-T.

Vector of opening areas for the tabular parameterization of valve opening area. The vector elements must correspond one-to-one with the elements in the B-T orifice spool travel vector parameter. The elements are listed in ascending order and must be greater than 0.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Area vs. spool travel.

  3. One of the following parameters:

    Positive spool position open connections to P-A and B-T.

    Negative spool position open connections to P-A and B-T.

Vector of control member travel distances for the tabular parameterization of volumetric flow rates. The spool travel vector forms an independent axis with the B-T orifice pressure drop vector, dp parameter for the 2-D dependent B-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and the first element must be 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to P-A and B-T.

    Negative spool position open connections to P-A and B-T.

Vector of pressure drop values for tabular parametrization of volumetric flow rate. The pressure drop vector forms an independent axis with the B-T orifice spool travel vector, ds parameter for the 2-D dependent B-T orifice volumetric flow rate table, q(ds,dp) parameter. The values are listed in ascending order and must be greater than 0. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to P-A and B-T.

    Negative spool position open connections to P-A and B-T.

M-by-N matrix of volumetric flow rates based on independent values of pressure drop and spool travel distance. M and N are the sizes of the correlated vectors:

  • M is the number of vector elements in the B-T orifice pressure drop vector, dp parameter.

  • N is the number of vector elements in the B-T orifice spool travel vector, ds parameter.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the following parameters:

    Positive spool position open connections to P-A and B-T.

    Negative spool position open connections to P-A and B-T.

Orifice area when the positive and negative spool positions feature the same orifice.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to either:

    • Linear - area vs. spool travel

    • Tabulated data - Area vs. spool travel

  3. One of the settings in each parameter:

    Positive spool position open connections to P-A and B-T.

    Negative spool position open connections to P-A and B-T.

Vector of pressure differential values over the valve when the positive and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the B-T Constant orifice volumetric flow rate vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the settings in each parameter:

    Positive spool position open connections to P-A and B-T.

    Negative spool position open connections to P-A and B-T.

Vector of pressure differential values over the valve when the positive and negative spool positions feature the same orifice. The vector elements correspond one-to-one with the elements in the B-T Constant orifice pressure drop vector parameter. The values are listed in ascending order. Linear interpolation is employed between table data points.

Dependencies

To enable this parameter, set:

  1. Area characteristics to Different for each flow path.

  2. Orifice parameterization to Tabulated data - Volumetric flow rate vs. spool travel and pressure drop.

  3. One of the settings in each parameter:

    Positive spool position open connections to P-A and B-T.

    Negative spool position open connections to P-A and B-T.

Faults

Enable externally or temporally triggered faults. When faulting occurs, the valve area normally set by the opening parameterization will be set to the value specified in the Spool position when faulted parameter.

Sets the faulted valve spool position. You can choose for the valve to seize when the spool is in the positive position, negative position, or at the position when faulting is triggered.

Dependencies

To enable this parameter, set Enable faults to On.

Whether a fault trigger occurs due to an external event or at a specified time.

When set to External, port Tr is enabled. A physical signal at port Tr that is greater than 0.5 triggers faulting.

When set to Temporal, when the Simulation time for fault event is reached, the valve area will be set to the value specified in the Spool position when faulted parameter.

Dependencies

To enable this parameter, set Enable faults to On.

When the Simulation time for fault event is reached, the valve area is set to the value specified in the Spool position when faulted parameter.

Dependencies

To enable this parameter, set Enable faults to On and Fault trigger to Temporal.

Introduced in R2021a