SimHydraulics
Reference
®
1
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SimHydraulics
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Reference
Revision History
March 2006 Online only New for Version 1.0 (Release 2006a+)
September 2006 Online only Revised for Version 1.1 (Release 2006b)
March 2007 Online only Revised for Version 1.2 (Release 2007a)
September 2007 Online only Revised for Version 1.2.1 (Release 2007b)
March 2008 Online only Revised for Version 1.3 (Release 2008a)
October 2008 Online only Revised for Version 1.4 (Release 2008b)
March 2009 Online only Revised for Version 1.5 (Release 2009a)
September 2009 Online only Revised for Version 1.6 (Release 2009b)
March 2010 Online only Revised for Version 1.7 (Release 2010a)
Block Reference
1
Accumulators ..................................... 1-2
Contents
Hydraulic Cylinders
Hydraulic Utilities
Local Hydraulic Resistances
Low-Pressure Blocks
Orifices
Pipelines
Pumps and Motors
Valves
Directional Valves
Flow Control Valves
Pressure Control Valves
Valve Actuators
Valve Forces
........................................... 1-7
.......................................... 1-8
............................................ 1-10
..................................... 1-13
............................... 1-3
................................. 1-4
............................... 1-6
................................. 1-9
................................. 1-10
............................... 1-12
............................ 1-12
................................... 1-12
........................ 1-5
v
2
A
Blocks — Alphabetical List
Bibliography
Glossary
Index
vi Contents
Block Reference
1
Accumulators (p. 1-2)
Hydraulic Cylinders (p. 1-3)
Hydraulic Utilities (p. 1-4)
Local Hydraulic Resistances (p. 1-5)
Low-Pressure Blocks (p. 1-6)
Orifices (p. 1-7) Hydraulic orifices, to be use d a s
Pipelines (p. 1-8)
Pumps a nd Motors (p. 1-9)
Valves (p. 1-10)
Hydraulic accumulators
Hydraulic cylinders
Environment blocks, such as
hydraulic fluid
Various local hydraulic resistances
Low-pressure blocks
valve building blocks
Hydraulic pipelines
Hydraulic pumps and motors
Hydraulic valves
1 Block Reference
Accumulators
Gas-Charged Accumulator Simulate hydraulic accumulator
withgasascompressiblemedium
Spring-Loaded A ccumulator Simulate hydraulic accumulator
with spring used for energy storage
1-2
Hydraulic Cylinders
Hydraulic Cylinders
Centrifugal Force in Rotating
Cylinder
Cylinder Friction Simulate friction in hydraulic
Double-Acting Hydraulic Cylinder Simulate hydraulic a ctuator exerting
Double-Acting Hydraulic Cylinder
(Simple)
Double-Acting Rotary Actuator Simulate double-acting hydraulic
Single-Acting Hydraulic Cylinder Simulate hydraulic actuator exerting
Single-Acting Hydraulic Cylinder
(Simple)
Single-Acting Rotary Actuator Simulate single-acting hydraulic
Simulate centrifugal force in rotating
hydraulic cylinders
cylinders
force in both directions
Simulate basic functionality of
double-acting hydraulic cylinder
rotary actuator
force in one direction
Simulate basic functionality of
single-acting hydraulic cylinder
rotary actuator
1-3
1 Block Reference
Hydraulic Utilities
Hydraulic Fluid
Reservoir
Set working fluid properties by
selecting from list of predefined
fluids
Simulate pressurized hydraulic
reservoir
1-4
Local Hydraulic Resistances
Local Hydraulic Resistances
Elbow
Gradual Area Change Simulate gradual enlargement or
Local Resistance
Pipe Bend
Sudden Area Change Simulate sudden enlargement or
T-junction
Simulate hydraulic resistance in
elbow
contraction
Simulate all kinds of hydraulic
resistances specified by loss
coefficient
Simulate hydraulic resistance in
pipe bend
contraction
Simulate hydraulic resistance of
T-junction in pipe
1-5
1 Block Reference
Low-Pressure Blocks
Constant Head Tank Simulate tank where pressurization
and fluid level remain constant
regardless of volume change
Hydraulic Pipe LP
Hydraulic Pipe LP with V ariable
Elevation
Resistive Pipe LP
Resistive Pipe LP with Variable
Elevation
Segmented Pipe LP Simulate hydraulic pipeline with
Variable Head Tank
Variable Head Three-Arm Tank Simulate tank with three hydraulic
Simulate hydraulic pipeline with
resistive, fluid compressibility, and
elevation properties
Simulate hydraulic pipeline with
resistive, fluid compressibility, and
variable elevation properties
Simulate hydraulic pipeline which
accounts for friction losses and port
elevations
Simulate hydraulic pipeline which
accounts for friction losses and
variable port elevations
resistive, fluid inertia, fluid
compressibility, and elev ati on
properties
Simulate tank with
constant pres surization and
volume-dependent fluid level
ports, constant pressurization, and
volume-dependent fluid level
1-6
Variable Head Two-Arm Tank Simulate tank with two hydraulic
ports, constant pressurization, and
volume-dependent fluid level
Orifices
Orifices
Annular Orifice Simulate hydraulic variable orifice
created by circular tube and round
insert
Fixed Orifice Simulate hydraulic orifice with
constant cross-sectional area
Orifice with Variable Area Round
Holes
Orifice with Variable Area Slot Simulate hydraulic variab le orifice
Variable Orifice Simulate generic hydraulic variable
Simulate hydraulic variable orifice
shaped as set of round holes drilled
in sleeve
shaped as rectangular slot
orifice
1-7
1 Block Reference
Pipelines
Hydraulic Pipeline
Rotating Pipe
Segmented Pipeline Simulate hydraulic pipeline with
Simulate hydraulic pipeline with
resistive and fluid compressibility
properties
Simulate hydraulic pipel ine created
by bore in rotating housing
resistive, fluid inertia, and fluid
compressibility properties
1-8
Pumps and Motors
Centrifugal Pump Simulate centrifugal pump
Pumps and Motors
Fixed-Displacement Pump
Hydraulic Motor
Variable-Displacement Hydraulic
Machine
Variable-Displacement Motor
Variable-Displacement
Pressure-Compensated Pump
Variable-Displacement Pump
Simulate fixed-displacement
hydraulic pump
Simulate fixed-displacement
hydraulic motor
Simulate variable-displ acement
reversible hydraulic machine with
regime-dependable efficiency
Simulate variable-displ acement
reversible hydraulic motor
Simulate hydraulic pump
maintaining preset pressure at
outlet by regulating its flow delivery
Simulate variable-displ acement
reversible hydraulic pump
1-9
1 Block Reference
Valves
Directional Valves (p. 1-10)
Flow Control Valves (p. 1-12) Hydraulic flow control valves
Pressure Control Valves (p. 1-12)
Valve Actuators (p. 1-12) Actuators for driving directional
Valve Forces (p. 1-13)
Direction
2-Way Dir
3-Way Di
4-Way D
4-Way Directional Valve A Simulate configuration A of
y Directional Valve B
4-Wa
al Valves
ectional Valve
rectional Valve
irectional Valve
Hydraulic directional valves
Hydraulic pressure control valves
valves
Blocks that simulate hydraulic
forces exerted on valves
Simulate hydraulic continuous
2-way directional valve
Simulate hydraulic continuous
3-way directional valve
Simulate hydraulic continuous
4-way directional valve
hydraulic continuous 4-way
directional valve
Simulate configuration B of
hydraulic continuous 4-way
directional valve
1-10
4-Way Directional Valve C Simulate configuration C of
hydraulic continuous 4-way
directional valve
Way Directional Valve D
4-
-Way Directional Valve E
4
Simulate configuration D of
hydraulic continuous 4-way
directional valve
Simulate configuration E of
hydraulic continuous 4-way
directional valve
Val v e s
4-Way Directional Valve F
Simulate configuration F of
hydraulic continuous 4-way
directional valve
4-Way Directional Valve G Simulate configuration G of
hydraulic continuous 4-way
directional valve
4-Way Directional Valve H
Simulate configuration H of
hydraulic continuous 4-way
directional valve
4-Way Directional Valve K
Simulate configuration K of
hydraulic continuous 4-way
directional valve
4-Way Ideal Valve
Simulate hydraulic 4-way
critically-centered valve
6-Way Directional Valve A Simulate configuration A of
hydraulic continuous 6-way
directional valve
Cartridge Valve Insert Simulate hydraulic cartridge valve
insert
Cartridge Valve Insert with Conical
Seat
Simulate hydraulic cartridge valve
insert with conical seat
Check Valve Simulate hydraulic valve that allows
flow in one direction only
Pilot-Operated Check Valve Simulate hydraulic check valve that
allows flow in one direction, but can
be disabled by pilot pressure
Shuttle Valve Simulate hydraulic valve that allows
flow in one direction only
1-11
1 Block Reference
Flow Control Val
Ball Valve
Ball Valve with Conical Seat Simulate hydraulic ball valve with
Needle Valve
Poppet Valve
Pressure-Compensated Flow Control
Valve
Pressure C
Pressure Compensator Simulate hydraulic pressure
Pressur
Pressure Relief Valve Simulate pressure control valve
eReducingValve
ontrol Valves
ves
Simulate hydraulic ball valve
conical seat
Simulate hydraulic needle valve
Simulate hydraulic poppet valve
Simulate hydraulic pressure
compensating valve
compensating valve
Simulate pressure control valve
maintaining reduced pressure in
portion of system
maintaining preset pressure in
system
1-12
Valve
2-Position Valve Actuator Simulate actuator for two-position
3-Position Valve Actuator Simulate actuator for three-position
Hydraulic 4-Port Cartridge Valve
Actuator
Hydraulic Cartridge Valve Actuator Simulate double-acting hydraulic
Actuators
valves
valves
Simulate double-acting hydraulic
valve actuator driven by four
pressures
actuator for cartridge valves
Val v e s
Hydraulic Double-Acting Valve
Actuator
Hydraulic Single-Acting Valve
Actuator
Proportional and Servo-Valve
Actuator
Valve Actuator Simulate simplified model of valve
Simulate double-acting hydraulic
valve actuator
Simulate single-acting hydraulic
valve actuator
Simulate continuous valve d river
with output proportional to input
signal
driver
Valve Forces
Spool O rifice Hydraulic Force Simulate axial hydraulic force
exerted on spoo l
Valve Hydraulic Force
Simulate axial hydraulic static force
exerted on valve
1-13
1 Block Reference
1-14
2
Blocks — Alphabetical List
2-Position Valve Actuator
Purpose Simulate actuator for two-position valves
Library Valve Actuators
Description The 2-Position Valve Actuator block represents an actuator that you can
use with directional valves to control their position. This actuator can
drive a two-position valve. The block is developed as a data-sheet-based
modelandallitsparametersaregenerally provided in catalogs or data
sheets. The key parameters are the stroke, switch-on, and switch-off
times.
The block accepts a physical input signal and produces a physical
output signal that can be associated with a mechanical translational or
rotational push-p in motion. Connect the block output to the directional
valve control port.
The actuator is represented as an ideal transducer, where output
does not depend on the load exerted on the push-pin and the push-pin
motion profile remains the same under any loading conditions. The
motion profile represents a typical transition curve for electromagnetic
actuators and is shown in the following figure:
2-2
2-Position Valve Actuator
The push-pin is actuated when the input signal value crosses the
threshold of 50% of the nominal input s ignal, where Nominal signal
value is a block parameter. The motion is divided into three phases,
equal in time: delay (
motion at constant velocity (
time (
t
) elapses . At this moment, the push-pin reaches the specified
stroke value (
on
x
str
t
), motion at constant acceleration (t2), and
1
t
). The motion stops when the switch-on
3
). To return the push-pin into initial position, the
control signal must cross back through the threshold of 50% of the
nominal input signal, w hich causes the push-pin to retract. The
retract motion follows exactly the same profile but “stretches” over the
2-3
2-Position Valve Actuator
switch-off time. Switching-on time and Switching-off time are the
block parameters.
The transition in any direction can be interrupted at any time by
changing the input signal. If motion is interrupted, the switch-on
or switch-off times are proportionally decreased depending on the
instantaneous push-pin position.
The push-pin is actuated only by positive signal, similar to the AC or DC
electromagnets. The direction of push-pin motion is controlled by the
Actuator orientation parameter, which can have one of two values:
Acts in positive direction or Acts i n negative direction.
Basic
Assumptions
and
Limitations
The model is based on the following assumption:
• Push-pin loading, such as inertia, spring, hydraulic forces, and so on,
is not taken into account.
2-4
Dialog
Box a nd
Parameters
2-Position Valve Actuator
Push-pin stroke
The push-pin stroke. The default value is
Switching-on time
Time necessary to fully extend the push-pin after the control
signal is applied. The default value is
0.01 m.
0.1 s.
2-5
2-Position Valve Actuator
Switching-off time
Time necessary to retract push-pin from fully extended position
after the input signal is removed. The default value is
Nominal signal value
Sets the value of the nominal inputsignal. Theoutputmotionis
initiated as the input signal crosses 50% value of the nominal
signal. Other than that, the input signal has no effect on the
motion profile. This parameter is meant to reproduce the rated
voltage feature of an electromagnet. The default value is
Initial position
Specifies the initial position of the push-pin. The parameter can
have one of two values:
value is
In selecting the initial position, consider the following:
• Thesteady-statepush-pinposition always corresponds to the
Retracted.
control signal. In other words, zero or negative signal keeps the
push-pin at
0.1 s.
24.
Extended or R etra cted. The default
Retracted, and positive signal — at Extended.
2-6
• At the start of simulation, if there is a discrepancy between
the initial position of the push-pin, as specified by the Initial
position parameter, and the control signal, the push-pin
immediately starts moving towards the steady-state position
designated by the control signal.
Actuator orientation
Parameter controls the directionofthepush-pinmotionandcan
have one of two v alues:
in negative direction
Acts in positive direction or Acts
. The first value causes the push-pin to
move in positive direction, similarly to the action of electromagnet
A attached to a directional valve. If the parameter is set to
in negative direction
, the control signal causes the push-pin
to move in negative direction from the initial position. The default
value is
Acts in positive direction.
Acts
2-Position Valve Actuator
Restricted Parameters
When your model is in Restricted editing mode, you cannot modify the
following parameters:
• Initial position
• Actuator orientation
All other block parameters are available for modification.
Ports The block has one physical signal input port, associated with the input
signal, and one physical signal output port, associated with the output
signal (push-pin displacement).
Examples In the 2-Position Valve Actuator demo (sh_2_pos_valve_actuator),
the hydraulic circuit contains two actuators. The first one is set to
start from the retracted position, while the second one starts from the
extended position. Both actuators are driven with a Pulse Generator.
The actuators start extending at 1 s, but the second actuator first
retracts from 0.01 m to zero, since it was initially extended and there
was no signal keeping it there.
In the Hydraulic Circuit with Single-Acting Cylinder demo
(
sh_circuit_sa_cylinder), the 2-Position Valv e Actuator block is used
along w ith a 3-Way Directional Valve block to simulate an electrically
operated 3-way directional valve.
See Also 3-Position Valve A ctuator
Hydraulic Double-Acting Valve Actuator
Hydraulic Single-Acting Valve Actua tor
Proportional and Servo-Valve Actuator
2-7
2-Way Directional Valve
Purpose Simulate hydraulic continuous 2-way directional valve
Library Directional Valves
Description The 2-Way Directional Valve block represents a continuous, 2-way
directional valve, also referred to as a shut-off valve. It is the device
that controls the connection between two lines. The block has two
hydraulic connections, corresponding to inlet port (P) and outlet port
(A), and one physical signal port connection (S), which controls the
spool position. The block is built based on a Variable Orifice block,
where the Orifice orientation parameter is set to
direction
and its instantaneous opening
hx x=+
. This means that positive signal x at port S opens the orifice,
h is computed as follows:
0
where
Opens in positive
2-8
h
x
0
x
Orifice opening
Initial opening
Control member displacement from initial position
Because the block is based on a variable orifice, you can choose one of
the following model parameterization options:
•
By maximum area and ope ning — Use this option if the data sheet
provides only the orifice maximum area and the control member
maximum stroke.
•
By area vs. opening table — Use this option if the catalog or
data sheet provides a table of the orifice passage area based on the
control member displacement
By pressure-flow characteristic — Use this option if the catalog
•
A=A(h).
or data sheet provides a two-dimensional table of the p ressure-flow
characteristics
q=q(p,h).
2-Way Directional Valve
In the first case, the passage area is assumed to be linearly dependent
on the control member displacement, that is, the orifice is assumed to be
closed at the initial p o s ition of the control member (zero displacement),
and the maximum opening takes place at the maximum displacement.
In the second case, the passage area is determined by one-dimensional
interpolation from the table
analytically, which additionally requires data such as flow discharge
coefficient, critical Reynolds number, and fluid density and viscosity.
The computation accounts for the laminar and turbulent flow regimes
by m onitoring the Reynolds number and comparing its value with the
critical Reynolds number. See the Variable Orifice block reference page
for details. In both cases, a small leakage area is assumed to exist even
after the orifice is completely closed. Physically, it represents a possible
clearance in the clos ed valve, but the main purpose of the parameter is
to maintain numerical integrity of the circuit by preventing a portion of
the system from getting isolated after the valve is completely closed.
An isolated or “hanging” part of the system could affect computational
efficiency and even cause failure of computation.
In the third case, when an orifice is defined by its pressure-flow
characteristics, the flow rate is determined by two-dimensional
interpolation. In this case, neither flow regime nor leakage flow
rate is taken into account, because these features are assumed to be
introduced through the tabulated data. Pressure-flow characteristics
are specified with three data sets: array of orifice openings, array of
pressure differentials across the orifice, and matrix of flow rate values.
Each value of a flow rate corresponds to a specific combination of an
opening and pressure differential. In other words, characteristics must
be presented as the Cartesian mesh, i.e., the function values must
be specified at vertices of a rectangular a rray. The argument arrays
(openings and pressure differentials) must be strictly monotonically
increasing. The v ertices can be nonuniformly spaced. You have a choice
of three interpolation methods and two extrapolation methods.
A=A(h).Flowrateisdetermined
The block positive direction is from port A to port B. This means that the
flow rate is positive if it flows from A to B and the pressure differential
2-9
2-Way Directional Valve
is determined as
port
S opens the valve.
pp p
=−
AB
. Positive signal at the physica l signal
Basic
Assumptions
and
Limitations
Dialog
Box a nd
Parameters
The model is based on the following assumptions:
• Fluid inertia is not taken into account.
• Spool loading, such as inertia , spring, hydraulic forces, and so on,
is not taken into account.
2-10
2-Way Directional Valve
2-11
2-Way Directional Valve
2-12
Model p
Selec
•
arameterization
t one of the following metho ds for specifying the v alve :
By max
maxim
The p
disp
of th
open
the
imum area and opening
um valve passage area and the maximum valve opening.
assage area is linearly dependent on the control member
lacement, that is, the valve is closed at the initial position
e control member (zero displacement), and the maximum
ing takes place at the maximum displacement. This is
default method.
— Provide values for the
2-Way Directional Valve
• By area vs. opening table — Provide tabulated data of
valve openings and corresponding valve passage areas. The
passage area is determined by one-dimensional table lookup.
You have a choice of three interpolation methods and two
extrapolation m ethods.
•
By pressure-flow characteristic — Provide tabulated data
of valve openings, pressure differentials, and corresponding
flow rates. The flow rate is determined by tw o-dimensional
table lookup. You have a choice of three interpolation methods
and two extrapolation methods.
Valve passage m aximum area
Specify the area of a fully opened valve. The parameter value
must be greater than zero. The default value is
parameter is used if Model parameterization is set to
maximum area and opening
.
Valve maximum opening
Specify the maximum displacement of the control member. The
parameter value must be greater than zero. The default value is
5e-3 m. This parameter is used if Model parameterization is
set to
By maximum area and openi ng.
5e-5 m^2. This
By
Tabulated valve openings
Specify the vector of input values for valve openings as a
tabulated 1-by-
m array. The input values vector must be strictly
monotonically increasing. The values can be nonuniformly
spaced. You must provide at least three values. The default
values, in meters, are
parameterization is set to
[-0.002 0 0.002 0.005 0 .015 ].IfModel
By area vs. opening table,the
Tabulated valve openings values will be used together with
Tabulated valve passage area values for one-dimensional table
lookup. If Model parameterization is set to
characteristic
,theTabulated valve openings values will
By pressure-flow
be used together with Tabulated pre ss ure differentials and
Tabulated flow rates for two-dimensional table lookup.
2-13
2-Way Directional Valve
Tabulated valve passage area
Specify the vector of output values for valve passage area as a
tabulated 1-bythesamesizeasthevalveopeningsvector. Allthevaluesmust
be positive. The default values, in m^2, are
4.0736e-05 0.00011438 0.00034356]
if Model parameterization is set to
.
table
Tabulated pressure differentials
Specify the vector of input values for pressure differentials as a
tabulated 1-bymonotonically increasing. The values can be nonuniformly spaced.
You must provide at least three values. The default values, in
Pa, are
parameter is used if Model parameterization is set to
pressure-flow characteristic
Tabulated flow rates
Specify the output values for flow rates as a tabulated
matrix, defining the function values at the input grid vertices.
Each value in t he matrix specifies f low rate taking place at a
specific combination of valve opening and pressure differential.
The matrix size must match the dimensions defined by the input
vectors. The default values, in m^3/s, are:
[-1e+07 -5e+06 -2e+06 2e +06 5e+06 1e+07].This
m array. The valve passage area vector must be
[1e-09 2.0352e-07
. This parameter is used
By area vs. opening
n array. The input values vector must be strictly
By
.
m-by-n
2-14
[-1e-07 -7.0711e-08 -4.4721e-08 4.4721e-08 7.0711e-08 1e-07;
-2.0352e-05 -1.4391e-05 -9.1017e-06 9.1017e-06 1.4391e-05 2.0352e-05;
-0.0040736 -0.0028805 -0.0018218 0.0018218 0.0028805 0.0040736;
-0.011438 -0.0080879 -0.0051152 0.0051152 0.0080879 0.011438;
-0.034356 -0.024293 -0.015364 0.015364 0.024293 0.034356;]
This parameter is used if Model parameterization is set to By
pressure-flow characteristic
.
Interpolation method
Select one of the following interpolation methods for
approximating the output value when the input value is between
two consecutive grid points:
2-Way Directional Valve
• Linear — For one-dimensional table lookup (By area
vs. opening table
For two-dimensional table lookup (
characteristic
which is an extension of linear interpolation for functio ns in
two variables.
•
Cubic — For one-dimensional table lookup (By area
vs. opening table
Interpolation Polinomial (PCHIP). For two-dimensional table
lookup (
By pressure-flow characteristic), uses the bicubic
interpolation algorithm.
•
Spline — For one-dimensional table lookup (By area vs.
opening table
For two-dimensional table lookup (
characteristic
algorithm.
For more information on interpolation algorithms, see the PS
Lookup Table (1D) and PS Lookup Table (2D) block reference
pages.
), uses a linear interpolation function.
By pressure-flow
), uses a bilinear interpolation algorithm,
), uses the Piecewise Cubic Hermite
), uses the cubic spline interpolation a lgorithm.
By pressure-flow
), uses the bicubic spline interpolation
Extrapolation method
Select one of the following extrapolation methods for determining
the output value when the input value is outside the range
specified in the ar gument list:
•
From last 2 points — Extrapolates u sing the linear method
(regardless of the interpolation method specified), based on
the last two output values at the appropriate end of the range.
That is, the block uses the first and second specified output
values if the input value is below the specified range, and the
two l ast specified output values if the input value is above the
specified range.
•
From last point — Uses the last specified output value at the
appropriate end of the range. That is, the block uses the last
specified output value for all input values greater than the last
2-15
2-Way Directional Valve
specified input argument, and the first specified output value
for all input values less than the first specified input argument.
For more informatio n on extrapolation algorithms, see the PS
Lookup Table (1D) and PS Lookup Table (2D) block reference
pages.
Flow discharge coefficient
Semi-empirical parameter for valve capacity characterization. Its
value depends on the geometrical properties of the valve, and
usually is provided in textbooks or manufacturer data sheets.
The default value is
Initial opening
Orifice initial opening. The parameter can be positive
(underlapped orifice), negative (overlapped orifice), or equal to
zero for zero lap configuration. The default value is
Critical Reynolds number
The maximum Reynolds number for laminar flow. The transition
from laminar to turbulent re gime is supposed to take place
when the Reynolds number reaches this value. The value
of the parameter depends on orifice geometrical profile, and
the recommendations on the parameter value can be found in
hydraulic textbooks. The default v alue is
0.7.
0.
12.
2-16
Leakage area
The total a rea of possible leaks in the completely closed valve.
The main purpose of the parameter is to maintain numerical
integrity of the circuit by preventing a portion of the system from
getting isolated after the valve is completely closed. An isolated or
“hanging” part of the system could affect computational efficiency
and even cause failure of computation. Extreme caution should
be exercised i f the parameter is s et to 0. The default value is
1e-12 m^2.
2-Way Directional Valve
Restricted Parameters
When your model is in Restricted editing mode, you cannot modify the
following parameters:
• Model parameterization
• Interpolation method
• Extrapolation method
All other block parameters are available for modification. The actual
set of modifiable block parameters depends on the value of the Model
parameterization parameter at the time the model entered Restricted
mode.
Global
Parameters
Fluid density
The parameter is determined by the type of working fluid selected
for the system under design. Use the Hydraulic Fluid block or the
Custom Hydraulic Fluid block to specify the fluid properties.
Fluid kinematic viscosity
The parameter is determined by the type of working fluid selected
for the system under design. Use the Hydraulic Fluid block or the
Custom Hydraulic Fluid block to specify the fluid properties.
Ports The block has the following ports:
A
Hydraulic conserving port associated with the valve inlet.
B
Hydraulic conserving port associated with the valve outlet.
S
Physical signal port to control spool displacement.
Examples In the Hydraulic Closed-Loop Circuit with 2-Way Valve demo
(
sh_closed_loop_circuit_2_way_valve), the 2-Way Directional Valve
2-17
2-Way Directional Valve
block is used to control the position of a double-acting cylinder. At the
start of simulation, the valve is open by 0.42 mm to make the circuit
initial position as close as possible to its neutral position.
See Also 3-Way Directional Valve
4-Way Directional Valve
2-18
3-Position Valve Actuator
Purpose Simulate actuator for three-position valves
Library Valve Actuators
Description The 3-Position Valve Actuator block represents an actuator that
you can use with directional valves to control their po sition. This
actuator can drive a three-position valve. The block is developed as a
data-sheet-based model and all its parameters are generally provided in
catalogs or data sheets. The key parameters are the stroke, switch-on,
and switch-off times.
The block has two signal inputs associated with the activation signals
for electromagnets A or B. It produces a p hysical output signal that can
be associated with a mechanical translational or rotational push-pin
motion. Connect the block output to the directional valve control port.
The actuator is represented as an ideal transducer, where output
does not depend on the load exerted on the push-pin and the push-pin
motion profile remains the same under any loading conditions. The
motion profile represents a typical transition curve for electromagnetic
actuators. The following figure shows the motion profile for a case when
the input signal is applied long enough for the push-pin to reach the end
of the stroke (
push-pin to return to initial position:
x
), and then the input signal is removed, causing the
str
2-19
3-Position Valve Actuator
The push-pin is actuated when the input signal value crosses the
threshold of 50% of the nominal input s ignal, where Nominal signal
value is a block parameter. The motion is divided into three phases,
equal in time: delay (
motion at constant velocity (
time (
t
) elapses . At this moment, the push-pin reaches the specified
stroke value (
control signal must b e removed, which causes the push-pin to retract.
The retract motion also consists of three phases, equal in time: delay
(
velocity (
the switch-off time. Switching-on time and Switching-off time are
the block parameters.
on
t
), motion at constant acceleration (tar), and motion at constant
dr
x
). To return the push-pin into initial position, the
str
t
). It follows exactly the same profile but “stretches” over
vr
t
), motion at constant acceleration (tae), and
de
t
). The motion stops when the switch-on
ve
2-20
The signal applied to port A causes the output to move in positive
direction. To shift the push-pin in negative direction, you must apply
the signal to port B. Only one control signal can be applied at a time.
This means that if the actuator is being controlled by the signal at port
A, the push-pin must be allowed to return to initial position before the
control signal at port B can be processed. The transition in any direction
can be interrupted at any time by changing the input signal. If motion
3-Position Valve Actuator
is interrupted, the switch-on or switch-off times are proportionally
decreased depending on the instantaneous push-pin position.
Only positive signals activate the actuator. In other words, negative
signals at ports A and B have no effect on the actuator, which is similar
to the behavior of electromagnetically controlled 3-position directional
valves.
Basic
Assumptions
and
Limitations
The model is based on the following assumption:
• Push-pin loading, such as inertia, spring, hydraulic forces, and so on,
is not taken into account.
2-21
3-Position Valve Actuator
Dialog
Box a nd
Parameters
2-22
Push-pin stroke
The push-pin stroke. The default value is
Switching-on time
Time necessary to fully extend the push-pin after the control
signal is applied. The default value is
Switching-off time
Time necessary to retract push-pin from fully extended position
after the input signal is removed. The default value is
0.01 m.
0.1 s.
0.1 s.
3-Position Valve Actuator
Nominal signal value
Sets the value of the nominal inputsignal. Theoutputmotionis
initiated as the input signal crosses 50% value of the nominal
signal. Other than that, the input signal has no effect on the
motion profile. This parameter is meant to reproduce the rated
voltage feature of an electromagnet. The default value is
Initial position
Specifies the initial position of the push-pin. The parameter
can have one of three values:
negative
In selecting the initial position, consider the following:
• Thesteady-statepush-pinposition always corresponds to the
control signal. In other words, zero signal keeps the push-pin
at
negative signal — at
• At the start of simulation, if there is a discrepancy between
the initial position of the push-pin, as specified by the Initial
position parameter, and the control signal, the push-pin
immediately starts moving towards the steady-state position
designated by the control signal.
,orNeutral. The default value is Neutral.
Neutral, positive signal — at Extended positive,and
Extended positive, Extended
Extended negative.
24.
Restricted Parameters
When your model is in Restricted editing mode, you cannot modify the
following parameter:
• Initial position
All other block parameters are available for modification.
Ports The block has the following ports:
A
PhysicalsignalinputportassociatedwiththeportAinputsignal.
2-23
3-Position Valve Actuator
B
PhysicalsignalinputportassociatedwiththeportBinputsignal.
The block also has one physical signal output port, which is associated
with the output signal (push-pin displacement).
Examples In the 3-Position Valve Actuator demo (sh_3_pos_valve_actuator),
all three actuators are set to different strokes, switch-on and switch-off
times, and initial positions. If the initial position is not
control signal at the beginning of simulation equals zero, the push-pin
starts moving towards neutral position,astheactuatorsAandCshow
in the demo.
See Also 2-Position Valve A ctuator
Hydraulic Double-Acting Valve Actuator
Hydraulic Single-Acting Valve Actua tor
Proportional and Servo-Valve Actuator
Neutral and the
2-24
3-Way Directional Valve
Purpose Simulate hydraulic continuous 3-way directional valve
Library Directional Valves
Description The 3-Way Directional Valve block represents a continuous,
symmetrical, 3-way directional valve. The fluid flow is pumped in
the v alve through the inlet line and is distributed between an outside
pressure line (usually connected to a single-acting actuator) and the
return line. The block has three hydraulic connections, corresponding
to inlet port (P), actuator port (A), and return port (T), and one physical
signal port connection (S), which controls the spool position. The block
is built of two Variable Orifice blocks, connected as shown in the
following diagram.
One Variable Orifice block, called orifice_PA, is installed in the P-A
path. The second V aria bl e Orifice block, called orifice_AT,isinstalled
in the
signal, provided through the physical signal port S, but the Orifice
orientation parameter in the block instances is set in such a way that
positive signal at port
result, the openings of the orifices are computed as follows:
A-T path. Both blocks are controlled by the same position
S opens orifice_PA and closes orifice_AT.Asa
2-25
3-Way Directional Valve
hh x
=+
PA PA
hh x
AT AT
where
0
=−
0
h
PA
h
AT
h
PA0
h
AT0
x
Orifice opening for the orifice_PA block
Orifice opening for the orifice_AT block
Initial opening for the orifice_PA block
Initial opening for the orifice_AT block
Control member displacement from initial position
The valve simulated by the 3-Way Directional Valve block is assum ed to
be symmetrical. This means that both orifices are of the same shape
and size and are parameterized with the same method. You can choose
one of the following block parameterization options:
•
By maximum area and ope ning — Use this option if the data sheet
provides only the orifice maximum area and the control member
maximum stroke.
•
By area vs. opening table — Use this option if the catalog or
data sheet provides a table of the orifice passage area based on the
control member displacement
By pressure-flow characteristic — Use this option if the catalog
•
A=A(h).
or data sheet provides a two-dimensional table of the p ressure-flow
characteristics
q=q(p,h).
In the first case, the passage area is assumed to be linearly dependent
on the control member displacement, that is, the orifice is assumed to be
closed at the initial p o s ition of the control member (zero displacement),
and the maximum opening takes place at the maximum displacement.
In the second case, the passage area is determined by one-dimensional
interpolation from the table
A=A(h).Flowrateisdetermined
analytically, which additionally requires data such as flow discharge
2-26
3-Way Directional Valve
coefficient, critical Reynolds number, and fluid density and viscosity.
The computation accounts for the laminar and turbulent flow regimes
by m onitoring the Reynolds number and comparing its value with the
critical Reynolds number. See the Variable Orifice block reference page
for details. In both cases, a small leakage area is assumed to exist even
after the orifice is completely closed. Physically, it represents a possible
clearance in the clos ed valve, but the main purpose of the parameter is
to maintain numerical integrity of the circuit by preventing a portion of
the system from getting isolated after the valve is completely closed.
An isolated or “hanging” part of the system could affect computational
efficiency and even cause failure of computation.
In the third case, when an orifice is defined by its pressure-flow
characteristics, the flow rate is determined by two-dimensional
interpolation. In this case, neither flow regime nor leakage flow
rate is taken into account, because these features are assumed to be
introduced through the tabulated data. Pressure-flow characteristics
are specified with three data sets: array of orifice openings, array of
pressure differentials across the orifice, and matrix of flow rate values.
Each value of a flow rate corresponds to a specific combination of an
opening and pressure differential. In other words, characteristics must
be presented as the Cartesian mesh, i.e., the function values must
be specified at vertices of a rectangular a rray. The argument arrays
(openings and pressure differentials) must be strictly monotonically
increasing. The v ertices can be nonuniformly spaced. You have a choice
of three interpolation methods and two extrapolation methods.
If you need to simulate a nonsymmetrical 3-way valve (i.e., with
different orifices), use any of the variable orifice blocks from the
Building Blocks library (such as Orifice with Variable Area Round
Holes, Orifice with Variable Area Slot, or Variable Orifice) and connect
them the same way as the Variable Orifice blocks in the schematic
diagram of this 3-Way Directional Valve block.
Positive signal at the physical signal port
path and closes the orifice in the A-T path. The directionality of nested
blocks is clear from the schematic diagram.
S opens the orifice in the P-A
2-27
3-Way Directional Valve
Basic
Assumptions
and
Limitations
Dialog
Box a nd
Parameters
The model is based on the following assumptions:
• Fluid inertia is not taken into account.
• Spool loading, such as inertia , spring, hydraulic forces, and so on,
is not taken into account.
• Only symmetrical configuration of the valve is considered. In other
words, both orifices are assumed to have the same shape and size.
2-28
3-Way Directional Valve
2-29
3-Way Directional Valve
2-30
Model parameterization
Select one of the following methods for specify ing t he valve:
•
By maximum area and ope ning — Provide values for the
maximum valve passage area and the maximum valve opening.
The passage area is linearly dependent on the control member
displacement, that is, the valve is closed at the initial position
of the control member (zero displacement), and the maximum
3-Way Directional Valve
opening takes place at the maximum displacement. This is
the default method.
•
By area vs. opening table — Provide tabulated data of
valve openings and corresponding valve passage areas. The
passage area is determined by one-dimensional table lookup.
You have a choice of three interpolation methods and two
extrapolation m ethods.
•
By pressure-flow characteristic — Provide tabulated data
of valve openings, pressure differentials, and corresponding
flow rates. The flow rate is determined by tw o-dimensional
table lookup. You have a choice of three interpolation methods
and two extrapolation methods.
Valve passage m aximum area
Specify the area of a fully opened valve. The parameter value
must be greater than zero. The default value is
parameter is used if Model parameterization is set to
maximum area and opening
.
5e-5 m^2. This
By
Valve maximum opening
Specify the maximum displacement of the control member. The
parameter value must be greater than zero. The default value is
5e-3 m. This parameter is used if Model parameterization is
set to
By maximum area and openi ng.
Tabulated valve openings
Specify the vector of input values for valve openings as a
tabulated 1-by-
m array. The input values vector must be strictly
monotonically increasing. The values can be nonuniformly
spaced. You must provide at least three values. The default
values, in meters, are
parameterization is set to
[-0.002 0 0.002 0.005 0 .015 ].IfModel
By area vs. opening table,the
Tabulated valve openings values will be used together with
Tabulated valve passage area values for one-dimensional table
lookup. If Model parameterization is set to
characteristic
,theTabulated valve openings values will
By pressure-flow
2-31
3-Way Directional Valve
be used together with Tabulated pre ss ure differentials and
Tabulated flow rates for two-dimensional table lookup.
Tabulated valve passage area
Specify the vector of output values for valve passage area as a
tabulated 1-bythesamesizeasthevalveopeningsvector. Allthevaluesmust
be positive. The default values, in m^2, are
4.0736e-05 0.00011438 0.00034356]
if Model parameterization is set to
.
table
Tabulated pressure differentials
Specify the vector of input values for pressure differentials as a
tabulated 1-bymonotonically increasing. The values can be nonuniformly spaced.
You must provide at least three values. The default values, in
Pa, are
parameter is used if Model parameterization is set to
pressure-flow characteristic
[-1e+07 -5e+06 -2e+06 2e +06 5e+06 1e+07].This
m array. The valve passage area vector must be
[1e-09 2.0352e-07
. This parameter is used
By area vs. opening
n array. The input values vector must be strictly
By
.
2-32
Tabulated flow rates
Specify the output values for flow rates as a tabulated
matrix, defining the function values at the input grid vertices.
Each value in t he matrix specifies f low rate taking place at a
specific combination of valve opening and pressure differential.
The matrix size must match the dimensions defined by the input
vectors. The default values, in m^3/s, are:
[-1e-07 -7.0711e-08 -4.4721e-08 4.4721e-08 7.0711e-08 1e-07;
-2.0352e-05 -1.4391e-05 -9.1017e-06 9.1017e-06 1.4391e-05 2.0352e-05;
-0.0040736 -0.0028805 -0.0018218 0.0018218 0.0028805 0.0040736;
-0.011438 -0.0080879 -0.0051152 0.0051152 0.0080879 0.011438;
-0.034356 -0.024293 -0.015364 0.015364 0.024293 0.034356;]
This parameter is used if Model parameterization is set to By
pressure-flow characteristic
.
m-by-n
3-Way Directional Valve
Interpolation method
Select one of the following interpolation methods for
approximating the output value when the input value is between
two consecutive grid points:
•
Linear — For one-dimensional table lookup (By area
vs. opening table
For two-dimensional table lookup (
characteristic
which is an extension of linear interpolation for functio ns in
two variables.
•
Cubic — For one-dimensional table lookup (By area
vs. opening table
Interpolation Polinomial (PCHIP). For two-dimensional table
lookup (
By pressure-flow characteristic), uses the bicubic
interpolation algorithm.
•
Spline — For one-dimensional table lookup (By area vs.
opening table
For two-dimensional table lookup (
characteristic
algorithm.
), uses a linear interpolation function.
By pressure-flow
), uses a bilinear interpolation algorithm,
), uses the Piecewise Cubic Hermite
), uses the cubic spline interpolation a lgorithm.
By pressure-flow
), uses the bicubic spline interpolation
For more information on interpolation algorithms, see the PS
Lookup Table (1D) and PS Lookup Table (2D) block reference
pages.
Extrapolation method
Select one of the following extrapolation methods for determining
the output value when the input value is outside the range
specified in the ar gument list:
•
From last 2 points—Extrapolates using the linear method
(regardless of the interpolation method specified), based on
the last two output values at the appropriate end of the range.
That is, the block uses the first and second specified output
values if the input value is below the specified range, and the
2-33
3-Way Directional Valve
two l ast specified output values if the input value is above the
specified range.
•
From last point—Uses the last specified output value at the
appropriate end of the range. That is, the block uses the last
specified output value for all input values greater than the last
specified input argument, and the first specified output value
for all input values less than the first specified input argument.
For more informatio n on extrapolation algorithms, see the PS
Lookup Table (1D) and PS Lookup Table (2D) block reference
pages.
Flow discharge coefficient
Semi-empirical parameter for valve capacity characterization. Its
value depends on the geometrical properties of the valve, and
usually is provided in textbooks or manufacturer data sheets.
The default value is
Orifice P-A initial opening
Initial opening for the orifice in the
be positive (underlapped orifice), negative (overlapped orifice), or
equal to zero for zero lap configuration. The default value is
0.7.
P-A path. The parameter can
0.
2-34
Orifice A-T initial opening
Initial opening for the orifice in the
be positive (underlapped orifice), negative (overlapped orifice), or
equal to zero for zero lap configuration. The default value is
Critical Reynolds number
The maximum Reynolds number for laminar flow. The transition
from laminar to turbulent re gime is supposed to take place
when the Reynolds number reaches this value. The value
of the parameter depends on orifice geometrical profile, and
the recommendations on the parameter value can be found in
hydraulic textbooks. The default v alue is
Leakage area
The total a rea of possible leaks in the completely closed valve.
The main purpose of the parameter is to maintain numerical
A-T path. The parameter can
12.
0.
3-Way Directional Valve
integrity of the circuit by preventing a portion of the system from
getting isolated after the valve is completely closed. An isolated or
“hanging” part of the system could affect computational efficiency
and even cause failure of computation. Extreme caution should
be exercised i f the parameter is s et to 0. The default value is
1e-12 m^2.
Restricted Parameters
When your model is in Restricted editing mode, you cannot modify the
following parameters:
• Model parameterization
• Interpolation method
• Extrapolation method
All other block parameters are available for modification. The actual
set of modifiable block parameters depends on the value of the Model
parameterization parameter at the time the model entered Restricted
mode.
Global
Parameters
Fluid density
The parameter is determined by the type of working fluid selected
for the system under design. Use the Hydraulic Fluid block or the
Custom Hydraulic Fluid block to specify the fluid properties.
Fluid kinematic viscosity
The parameter is determined by the type of working fluid selected
for the system under design. Use the Hydraulic Fluid block or the
Custom Hydraulic Fluid block to specify the fluid properties.
Ports The block has the following ports:
P
Hydraulic conserving port associated with the pressure supply
line inlet.
2-35
3-Way Directional Valve
T
Hydraulic conserving port associated with the return line
connection.
A
Hydraulic conserving port associated with the actuator connection
port.
S
Physical signal port to control spool displacement.
Examples The 3-Way Directional Valve block is demonstrated in the
Hydraulic Circuit with 3-Way Valve and Differential Cylinder demo
(
sh_circuit_3_way_valve_diff_cylinder), where it is used to switch
between a conventional and differential connection of the cylinder.
See Also 2-Way Directional Valve
4-Way Directional Valve
2-36
4-Way Directional Valve
Purpose Simulate hydraulic continuous 4-way directional valve
Library Directional Valves
Description The 4-Way Directional Valve block represents a continuous 4-way
directional valve. The fluid is pumped in the valve through the inlet
line P and is distributed between two outside hydraulic lines A and B
(usually connected to a double-acting actuator) and the return line T.
The block has four h ydraulic connections, corresponding to inlet port
(P), actuator ports (A and B), and return port (T), and one physical
signal port connection (S), which controls the spool position.
There are multiple configurations o f 4-way directional valves, depending
on the port connections in three distinctive valve positions: leftmost,
neutral, and rightmost. This block lets you model the most popular
configurations by changing the initial openings of the orifices, as shown
in Basic 4-Way Directional Valve Configurations on page 2-39. Other
SimHydraulics
valve configurations. For more information, see “Modeling Directional
Valves” in the SimHydraulics User’s Guide.
®
blocks provide more 4-way and 6-way directional
The 4-Way D irectional Valve block is built of four Variable Orifice
blocks, connected as shown in the following diagram.
2-37
4-Way Directional Valve
The Variable Orifice blocks are installed a s follows: orif ice P-A is in the
P-A path, orifice P-B is in the P-B path, orifice A-T is in the A-T path,
and orifice B-T is in the
position signal, provided through the physical signal port S, but the
Orifice orientation parameter in the block instances is set in such a
way that positive signal at port
block diagram (orifices P-A and B-T ) and closes the orifices colored
yellow (orifices P-B and A-T). As a result, the openings of the orifices
are computed as follows:
B-T path. All blocks are controlled by the same
S opens the orifices colored blue in the
2-38
hh x
=+
PA PA
hh x
PB PB
hh x
AT AT
hh x
BT BT
0
=−
0
=−
0
=+
0
where
4-Way Directional Valve
h
PA
h
PB
h
AT
h
BT
h
PA0
h
PB0
h
AT0
h
BT0
x
Orifice opening for the Variable Orifice P-A block
Orifice opening for the Variable Orifice P-B block
Orifice opening for the Variable Orifice A-T block
Orifice opening for the Variable Orifice B-T block
Initial opening for the Variable Orifi ce P-A block
Initial opening for the Variable Orifi ce P-B block
Initial opening for the Variable Orifi ce A-T block
Initial opening for the Variable Orifi ce B-T block
Control member displacement from initial position
By default, all initial openings are set to zero. By adjusting their values,
you can obtain 11 different configurations, as shown in the following
table. T o specify the initial openings of the orifices, use the “Initial
Openings”onpage2-52taboftheblockdialogbox.
Basic 4-Way Directional Valve Configurations
No
1
Configuration
Initial Op en ing s
All four orifices are overlapped in neutral position:
• Orifice P-A initial opening <0
• Orifice P-B initial opening <0
• Orifice A-T initial opening <0
• Orifice B-T initial opening <0
2
All four orifices are open (underlapped) in neutral
position:
• Orifice P-A initial opening >0
• Orifice P-B initial opening >0
• Orifice A-T initial opening >0
2-39
4-Way Directional Valve
Basic 4-Way Directional Valve Configurations (Continued)
No
3
4
5
Configuration
Initial Op en ing s
• Orifice B-T initial opening >0
Orifices P-A and P-B are overlapped. Orifices A-T and
B-T are overlapped for more than valve stroke:
• Orifice P-A initial opening <0
• Orifice P-B initial opening <0
• Orifice A-T initial opening <–
• Orifice B-T initial opening <–valve_stroke
Orifices P-A and P-B are overlapped, while o rifices A-T
and B-T are open:
• Orifice P-A initial opening <0
• Orifice P-B initial opening <0
• Orifice A-T initial opening >0
• Orifice B-T initial opening >0
Orifices P-A and A-T areopeninneutralposition,while
orifices
P-B and B-T are overlapped:
valve_stroke
2-40
• Orifice P-A initial opening >0
• Orifice P-B initial opening <0
• Orifice A-T initial opening >0
• Orifice B-T initial opening <0
4-Way Directional Valve
Basic 4-Way Directional Valve Configurations (Continued)
No
6
7
8
Configuration
Initial Op en ing s
Orifice A-T is initially open, while all three remaining
orifices are overlapped:
• Orifice P-A initial opening <0
• Orifice P-B initial opening <0
• Orifice A-T initial opening >0
• Orifice B-T initial opening <0
Orifice B-T is initially open, while all three remaining
orifices are overlapped:
• Orifice P-A initial opening <0
• Orifice P-B initial opening <0
• Orifice A-T initial opening <0
• Orifice B-T initial opening >0
Orifices P-A and P-B are open, while orifices A-T and
B-T are overlapped:
• Orifice P-A initial opening >0
• Orifice P-B initial opening >0
• Orifice A-T initial opening <0
• Orifice B-T initial opening <0
2-41
4-Way Directional Valve
Basic 4-Way Directional Valve Configurations (Continued)
No
9
10
11
Configuration
Initial Op en ing s
Orifice P-A is initially open, while all three remaining
orifices are overlapped:
• Orifice P-A initial opening >0
• Orifice P-B initial opening <0
• Orifice A-T initial opening <0
• Orifice B-T initial opening <0
Orifice P-B is initially open, while all three remaining
orifices are overlapped:
• Orifice P-A initial opening <0
• Orifice P-B initial opening >0
• Orifice A-T initial opening <0
• Orifice B-T initial opening <0
Orifices P-B and B-T are open, while orifices P-A and
A-T are overlapped:
• Orifice P-A initial opening <0
• Orifice P-B initial opening >0
2-42
• Orifice A-T initial opening <0
• Orifice B-T initial opening >0
All four o rifices are assumed to be of the same shape and size and
are parameterized with the same method. You can choose one of the
following block parameterization options:
4-Way Directional Valve
• By maximum area and opening — Use this option if the data sheet
provides only the orifice maximum area and the control member
maximum stroke.
•
By area vs. opening table — Use this option if the catalog or
data sheet provides a table of the orifice passage area based on the
control member displacement
By pressure-flow characteristic — Use this option if the catalog
•
or data sheet provides a two-dimensional table of the p ressure-flow
characteristics
In the first case, the passage area is assumed to be linearly dependent
on the control member displacement, that is, the orifice is assumed to be
closed at the initial p o s ition of the control member (zero displacement),
and the maximum opening takes place at the maximum displacement.
In the second case, the passage area is determined by one-dimensional
interpolation from the table
analytically, which additionally requires data such as flow discharge
coefficient, critical Reynolds number, and fluid density and viscosity.
The computation accounts for the laminar and turbulent flow regimes
by m onitoring the Reynolds number and comparing its value with the
critical Reynolds number. See the Variable Orifice block reference page
for details. In both cases, a small leakage area is assumed to exist even
after the orifice is completely closed. Physically, it represents a possible
clearance in the clos ed valve, but the main purpose of the parameter is
to maintain numerical integrity of the circuit by preventing a portion of
the system from getting isolated after the valve is completely closed.
An isolated or “hanging” part of the system could affect computational
efficiency and even cause failure of computation.
q=q(p,h).
A=A(h).
A=A(h).Flowrateisdetermined
In the third case, when an orifice is defined by its pressure-flow
characteristics, the flow rate is determined by two-dimensional
interpolation. In this case, neither flow regime nor leakage flow
rate is taken into account, because these features are assumed to be
introduced through the tabulated data. Pressure-flow characteristics
are specified with three data sets: array of orifice openings, array of
pressure differentials across the orifice, and matrix of flow rate values.
2-43
4-Way Directional Valve
Each value of a flow rate corresponds to a specific combination of an
opening and pressure differential. In other words, characteristics must
be presented as the Cartesian mesh, that is, the function values must
be specified at vertices of a rectangular a rray. The argument arrays
(openings and pressure differentials) must be strictly monotonically
increasing. The v ertices can be nonuniformly spaced. You have a choice
of three interpolation methods and two extrapolation methods.
If you need to simulate a nonsymmetrical 4-way valve (that is, with
different orifices), use any of the variable orifice blocks from the Orifices
library (such as Orifice with Variable Area Round Holes, Orifice with
Variable Area Slot, or Variable Orifice) and connect them the same way
as the Variable Orifice blocks in the schematic diagram of this 4-Way
Directional Valve block.
Basic
Assumptions
and
Limitations
Dialog
Box a nd
Parameters
Positive signal at the physical signal port
and B-T paths and closes the orifices in the P-B and A-T paths. The
directionality of nested blocks is clear from the schematic diagram.
The model is based on the following assumptions:
• Fluid inertia is not taken into account.
• Spool loading, such as inertia , spring, hydraulic forces, and so on,
is not taken into account.
• Only symmetrical configuration of the valve is considered. In other
words, all four orifices are assumed to have the same shape and size.
The block dialog box contains two tabs:
• “Basic Parameters” on page 2-45
• “Initial Openings” on p age 2-52
S opens the orifices in the P-A
2-44
Basic Parameters
4-Way Directional Valve
2-45
4-Way Directional Valve
2-46
4-Way Directional Valve
Model parameterization
Select one of the following methods for specify ing t he valve:
•
By maximum area and ope ning — Provide values for the
maximum valve passage area and the maximum valve opening.
The passage area is linearly dependent on the control member
displacement, that is, the valve is closed at the initial position
of the control member (zero displacement), and the maximum
2-47
4-Way Directional Valve
opening takes place at the maximum displacement. This is
the default method.
•
By area vs. opening table — Provide tabulated data of
valve openings and corresponding valve passage areas. The
passage area is determined by one-dimensional table lookup.
You have a choice of three interpolation methods and two
extrapolation m ethods.
•
By pressure-flow characteristic — Provide tabulated data
of valve openings, pressure differentials, and corresponding
flow rates. The flow rate is determined by tw o-dimensional
table lookup. You have a choice of three interpolation methods
and two extrapolation methods.
Valve passage m aximum area
Specify the area of a fully opened valve. The parameter value
must be greater than zero. The default value is
parameter is used if Model parameterization is set to
maximum area and opening
5e-5 m^2. This
By
.
2-48
Valve maximum opening
Specify the maximum displacement of the control member. The
parameter value must be greater than zero. The default value is
5e-3 m. This parameter is used if Model parameterization is
set to
By maximum area and openi ng.
Tabulated valve openings
Specify the vector of input values for valve openings as a
tabulated 1-by-
m array. The input values vector must be strictly
monotonically increasing. The values can be nonuniformly
spaced. You must provide at least three values. The default
values, in meters, are
parameterization is set to
[-0.002 0 0.002 0.005 0 .015 ].IfModel
By area vs. opening table,the
Tabulated valve openings values will be used together with
Tabulated valve passage area values for one-dimensional table
lookup. If Model parameterization is set to
characteristic
,theTabulated valve openings values will
By pressure-flow
4-Way Directional Valve
be used together with Tabulated pre ss ure differentials and
Tabulated flow rates for two-dimensional table lookup.
Tabulated valve passage area
Specify the vector of output values for valve passage area as a
tabulated 1-bythesamesizeasthevalveopeningsvector. Allthevaluesmust
be positive. The default values, in m^2, are
4.0736e-05 0.00011438 0.00034356]
if Model parameterization is set to
.
table
Tabulated pressure differentials
Specify the vector of input values for pressure differentials as a
tabulated 1-bymonotonically increasing. The values can be nonuniformly spaced.
You must provide at least three values. The default values, in
Pa, are
[-1e+07 -5e+06 -2e+06 2e +06 5e+06 1e+07].This
parameter is used if Model parameterization is set to
pressure-flow characteristic
m array. The valve passage area vector must be
[1e-09 2.0352e-07
. This parameter is used
By area vs. opening
n array. The input values vector must be strictly
.
By
Tabulated flow rates
Specify the output values for flow rates as a tabulated
matrix, defining the function values at the input grid vertices.
Each value in t he matrix specifies f low rate taking place at a
specific combination of valve opening and pressure differential.
The matrix size must match the dimensions defined by the input
vectors. The default values, in m^3/s, are:
[-1e-07 -7.0711e-08 -4.4721e-08 4.4721e-08 7.0711e-08 1e-07;
-2.0352e-05 -1.4391e-05 -9.1017e-06 9.1017e-06 1.4391e-05 2.0352e-05;
-0.0040736 -0.0028805 -0.0018218 0.0018218 0.0028805 0.0040736;
-0.011438 -0.0080879 -0.0051152 0.0051152 0.0080879 0.011438;
-0.034356 -0.024293 -0.015364 0.015364 0.024293 0.034356;]
This parameter is used if Model parameterization is set to By
pressure-flow characteristic
.
m-by-n
2-49
4-Way Directional Valve
Interpolation method
Select one of the following interpolation methods for
approximating the output value when the input value is between
two consecutive grid points:
•
Linear — For one-dimensional table lookup (By area
vs. opening table
For two-dimensional table lookup (
characteristic
which is an extension of linear interpolation for functio ns in
two variables.
•
Cubic — For one-dimensional table lookup (By area
vs. opening table
Interpolation Polinomial (PCHIP). For two-dimensional table
lookup (
interpolation algorithm.
•
Spline — For one-dimensional table lookup (By area vs.
opening table
For two-dimensional table lookup (
characteristic
algorithm.
), uses a linear interpolation function.
By pressure-flow
), uses a bilinear interpolation algorithm,
), uses the Piecewise Cubic Hermite
By pressure-flow characteristic), uses the bicubic
), uses the cubic spline interpolation a lgorithm.
By pressure-flow
), uses the bicubic spline interpolation
2-50
For more information on interpolation algorithms, see the PS
Lookup Table (1D) and PS Lookup Table (2D) block reference
pages.
Extrapolation method
Select one of the following extrapolation methods for determining
the output value when the input value is outside the range
specified in the ar gument list:
•
From last 2 points — Extrapolates u sing the linear method
(regardless of the interpolation method specified), based on
the last two output values at the appropriate end of the range.
That is, the block uses the first and second specified output
values if the input value is below the specified range, and the
4-Way Directional Valve
two l ast specified output values if the input value is above the
specified range.
•
From last point — Uses the last specified output value at the
appropriate end of the range. That is, the block uses the last
specified output value for all input values greater than the last
specified input argument, and the first specified output value
for all input values less than the first specified input argument.
For more informatio n on extrapolation algorithms, see the PS
Lookup Table (1D) and PS Lookup Table (2D) block reference
pages.
Flow discharge coefficient
Semi-empirical parameter for valve capacity characterization. Its
value depends on the geometrical properties of the valve, and
usually is provided in textbooks or manufacturer data sheets.
The default value is
Critical Reynolds number
The maximum Reynolds number for laminar flow. The transition
from laminar to turbulent re gime is supposed to take place
when the Reynolds number reaches this value. The value
of the parameter depends on orifice geometrical profile, and
the recommendations on the parameter value can be found in
hydraulic textbooks. The default v alue is
0.7.
12.
Leakage area
The total a rea of possible leaks in the completely closed valve.
The main purpose of the parameter is to maintain numerical
integrity of the circuit by preventing a portion of the system from
getting isolated after the valve is completely closed. An isolated or
“hanging” part of the system could affect computational efficiency
and even cause failure of computation. Extreme caution should
be exercised i f the parameter is s et to 0. The default value is
1e-12 m^2.
2-51
4-Way Directional Valve
Initial Openings
2-52
Orifice P-A initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Variable Orifice P-A block. The
0.
4-Way Directional Valve
Orifice P-B initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Orifice A-T initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Orifice B-T initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Restricted Parameters
When your model is in Restricted editing mode, you cannot modify the
following parameters:
Variable Orifice P-B block. The
0.
Variable Orifice A-T block. The
0.
Variable Orifice B-T block. The
0.
Global
Parameters
• Model parameterization
• Interpolation method
• Extrapolation method
All other block parameters are available for modification. The actual
set of modifiable block parameters depends on the value of the Model
parameterization parameter at the time the model entered Restricted
mode.
Fluid density
The parameter is determined by the type of working fluid selected
for the system under design. Use the Hydraulic Fluid block or the
Custom Hydraulic Fluid block to specify the fluid properties.
2-53
4-Way Directional Valve
Fluid kinematic viscosity
The parameter is determined by the type of working fluid selected
for the system under design. Use the Hydraulic Fluid block or the
Custom Hydraulic Fluid block to specify the fluid properties.
Ports The block has the following ports:
P
Hydraulic conserving port associated with the pressure supply
line inlet.
T
Hydraulic conserving port associated with the return line
connection.
A
Hydraulic conserving port associated with the actuator connection
port.
B
Hydraulic conserving port associated with the actuator connection
port.
S
Physical signal port to control spool displacement.
Examples The 4-Way D i rectio nal Valve block in the Closed-Loop
Circuit with 4-Way Valve and Custom Cylinder demo
(
sh_closed_loop_circuit_4_way_valve_cust_cyl) is an open-center,
symmetrical valve controlling a double-acting cylinder.
See Also 2-Way Directional Valve
3-Way Directional Valve
4-Way Directional Valve A
4-Way Directional Valve B
4-Way Directional Valve C
2-54
4-Way Directional Valve D
4-Way Directional Valve E
4-Way Directional Valve F
4-Way Directional Valve G
4-Way Directional Valve H
4-Way Directional Valve K
6-Way Directional Valve A
4-Way Directional Valve
2-55
4-Way Directional Valve A
Purpose Simulate configuration A of hydraulic continuous 4-way directional
valve
Library Directional Valves
Description The 4-Way Directional Valve A block simulates a configuration o f
hydraulic continuous 4-way directional valve where the valve unloads
the pump in neutral position. The fluid is pumped in the valve through
the inlet line P and is distributed between two outside hydraulic lines A
and B (usually connected to a double-acting actuator) and the return
line T. The block has four hydraulic connections, corresponding to
inlet port (P), actuator ports (A andB),andreturnport(T),andone
physical signal port connection (S), which controls the spool position.
The block i s built of six Variab le Orifice blocks, connected as show n
in the following diagram.
2-56
All blocks are controlled by the same position signal, provided through
thephysicalsignalportS,buttheOrifice orientation parameter in
4-Way Directional Valve A
the block instances is set in such a way that positive signal at port S
opens the orifices colored blue in the block diagram (orifices P-A, B-T,
and T1-T ) and closes the orifices colored yellow (orifices A-T, P-B, and
P-T1). As a result, the openings of the orifices are computed as follows:
hh x
=+
PA PA
hh x
PB PB
hh x
AT AT
hh x
BT BT
hh x
PT PT110
hh x
TT TT110
where
0
=−
0
=−
0
=+
0
=−
=+
h
PA
h
PB
h
AT
h
BT
h
PT1
h
T1T
h
PA0
h
PB0
h
AT0
h
BT0
Orifice opening for the Variable Orifice P-A block
Orifice opening for the Variable Orifice P-B block
Orifice opening for the Variable Orifice A-T block
Orifice opening for the Variable Orifice B-T block
Orifice opening for the Variable Orifice P-T1 block
Orifice opening for the Variable Orifice T1-T block
Initial opening for the Variable Orifi ce P-A block
Initial opening for the Variable Orifi ce P-B block
Initial opening for the Variable Orifi ce A-T block
Initial opening for the Variable Orifi ce B-T block
2-57
4-Way Directional Valve A
Dialog
Box a nd
Parameters
h
PT10
h
T1T0
x
For information on the block parameterization options, basic parameter
descriptions, assumptions and limitations, global and restricted
parameters, see the 4 -W ay Directional V alve block r eference page.
The block dialog box contains two tabs:
• “Basic Parameters” on page 2-58
• “Initial Openings” on p age 2-59
Initial opening for the Variable Orifice P-T1 block
Initial opening for the Variable Orifice T1-T block
Control member displacement from initial position
Basic Parameters
See the documentation for the Basic Parameters tab of the 4-Way
Directional Valve block for parameter descriptions and default values.
2-58
Initial Openings
4-Way Directional Valve A
Orifice P-A initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Variable Orifice P-A block. The
-0.0025 m.
2-59
4-Way Directional Valve A
Orifice P-B initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Orifice A-T initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Orifice B-T initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
OrificeP-T1initialopening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Variable Orifice P-B block. The
-0.0025 m.
Variable Orifice A-T block. The
-0.0025 m.
Variable Orifice B-T block. The
-0.0025 m.
Variable Orifice P-T1 block. The
0.0025 m.
Orifice T1-T initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Ports The block has the following ports:
P
Hydraulic conserving port associated with the pressure supply
line inlet.
T
Hydraulic conserving port associated with the return line
connection.
2-60
Variable Orifice T1-T block. The
0.0025 m.
A
Hydraulic conserving port associated with the actuator connection
port.
B
Hydraulic conserving port associated with the actuator connection
port.
S
Physical signal port to control spool displacement.
See Also 4-Way Directional Valve
4-Way Directional Valve B
4-Way Directional Valve C
4-Way Directional Valve D
4-Way Directional Valve E
4-Way Directional Valve F
4-Way Directional Valve A
4-Way Directional Valve G
4-Way Directional Valve H
4-Way Directional Valve K
6-Way Directional Valve A
2-61
4-Way Directional Valve B
Purpose Simulate configuration B of hydraulic continuous 4-way directional
valve
Library Directional Valves
Description The 4-Way Directional Valve B block simulates a configuration
of hydraulic continuous 4-way directional valve where port A is
permanently connected to port P, and all four ports are interconnected
in neutral position. The fluid is pumped in the v alve through the inlet
line P and is distributed between two outside hydraulic lines A and B
(usually connected to a double-acting actuator) and the return line T.
The block has four h ydraulic connections, corresponding to inlet port
(P), actuator ports (A and B), and return port (T), and one physical
signal port connection (S), which controls the spool position. The block
is built of a Fixed Orifice block in the P-A path and four Variable Orifice
blocks, connected as shown in the following diagram.
2-62
4-Way Directional Valve B
All Variable Orifice blocks are controlled by the same position
signal, provided through the physical signal port S, but the Orifice
orientation parameter in the block instances is set in such a way that
positive signal at port
diagram (orifices A-T1 and P-B ) and closes the orifices colored yellow
(orifices T1-T and B-T). As a result, the openings of the orifices are
computed as follows:
hh x
=−
AT AT110
=−
hh x
PB PB
hh x
TT TT110
hh x
BT BT
0
=+
=+
0
where
S opens the orifices colored blue in the block
h
h
h
h
h
h
h
h
x
AT1
PB
T1T
BT
AT10
PB0
T1T0
BT0
Orifice opening for the Variable Orifice A-T1 block
Orifice opening for the Variable Orifice P-B block
Orifice opening for the Variable Orifice T1-T block
Orifice opening for the Variable Orifice B-T block
Initial opening for the Variable Orifice A-T1 block
Initial opening for the Variable Orifi ce P-B block
Initial opening for the Variable Orifice T1-T block
Initial opening for the Variable Orifi ce B-T block
Control member displacement from initial position
For information on the block parameterization options, basic parameter
descriptions, assumptions and limitations, global and restricted
parameters, see the 4 -W ay Directional V alve block r eference page.
2-63
4-Way Directional Valve B
Dialog
Box a nd
Parameters
The block dialog box contains two tabs:
• “Basic Parameters” on page 2-64
• “Initial Openings” on p age 2-65
Basic Parameters
See the documentation for the Basic Parameters tab of the 4-Way
Directional Valve block for parameter descriptions and default values.
There is one additional parameter:
Path P-A passage area
Specify the area of the P-A passage. The parameter value must be
greater than zero. The default value is
is used if Model parameterization is set to
and opening
.
5e-5 m^2. This parameter
By maximum area
2-64
Initial Openings
4-Way Directional Valve B
Orifice P-B initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
Variable Orifice P-B block. The
2-65
4-Way Directional Valve B
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Orifice B-T initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
OrificeA-T1initialopening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Orifice T1-T initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
0.0025 m.
Variable Orifice B-T block. The
0.0025 m.
Variable Orifice A-T1 block. The
0.0025 m.
Variable Orifice T1-T block. The
0.0025 m.
Ports The block has the following ports:
P
Hydraulic conserving port associated with the pressure supply
line inlet.
T
Hydraulic conserving port associated with the return line
connection.
A
Hydraulic conserving port associated with the actuator connection
port.
B
Hydraulic conserving port associated with the actuator connection
port.
2-66
S
Physical signal port to control spool displacement.
See Also 4-Way Directional Valve
4-Way Directional Valve A
4-Way Directional Valve C
4-Way Directional Valve D
4-Way Directional Valve E
4-Way Directional Valve F
4-Way Directional Valve G
4-Way Directional Valve H
4-Way Directional Valve K
6-Way Directional Valve A
4-Way Directional Valve B
2-67
4-Way Directional Valve C
Purpose Simulate configuration C of hydraulic continuous 4-way directional
valve
Library Directional Valves
Description The 4-Way Directional Valve C block simulates a configuration o f
hydraulic continuous 4-way directional valve where port P is connected
to port A and port B is connected to port T in the left position; in the
right position, both port A and port B are connected to P; and all ports
are interconnected in neutral position. The fluid is pumped in the valve
through the inlet line P and is distributed between two outside hydraulic
lines A and B (usually connected to a double-acting actuator) and the
return line T. The block has four hydraulic connections, corresponding
to inlet port (P), actuator ports (A and B), and return port (T), and one
physical signal port connection (S), which controls the spool position.
The block is built of a Fixed Orifice block in the P-B path and four
Variable Orifice blocks, connected as shown in the following diagram.
2-68
4-Way Directional Valve C
All Variable Orifice blocks are controlled by the same position
signal, provided through the physical signal port S, but the Orifice
orientation parameter in the block instances is set in such a way that
positive signal at port
diagram (orifices B-T1 and A-T ) and closes the orifices colored yellow
(orifices P-A and T1-T). As a result, the openings of the orifices are
computed as follows:
hh x
=−
PA PA
hh x
AT AT
hh x
BT BT110
hh x
TT TT110
0
=+
0
=+
=−
where
S opens the orifices colored blue in the block
h
h
h
h
h
h
h
h
x
PA
AT
BT1
T1T
PA0
PB0
BT10
T1T0
Orifice opening for the Variable Orifice P-A block
Orifice opening for the Variable Orifice A-T block
Orifice opening for the Variable Orifice B-T1 block
Orifice opening for the Variable Orifice T1-T block
Initial opening for the Variable Orifi ce P-A block
Initial opening for the Variable Orifi ce P-B block
Initial opening for the Variable Orifice B-T1 block
Initial opening for the Variable Orifice T1-T block
Control member displacement from initial position
For information on the block parameterization options, basic parameter
descriptions, assumptions and limitations, global and restricted
parameters, see the 4 -W ay Directional V alve block r eference page.
2-69
4-Way Directional Valve C
Dialog
Box a nd
Parameters
The block dialog box contains two tabs:
• “Basic Parameters” on page 2-70
• “Initial Openings” on p age 2-71
Basic Parameters
See the documentation for the Basic Parameters tab of the 4-Way
Directional Valve block for parameter descriptions and default values.
There is one additional parameter:
Path P-B passage area
Specify the area of the P-B passage. The parameter value must be
greater than zero. The default value is
is used if Model parameterization is set to
and opening
.
5e-5 m^2. This parameter
By maximum area
2-70
Initial Openings
4-Way Directional Valve C
2-71
4-Way Directional Valve C
Orifice P-A initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Orifice A-T initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
OrificeB-T1initialopening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Orifice T1-T initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Variable Orifice P-A block. The
0.0025 m.
Variable Orifice A-T block. The
0.0025 m.
Variable Orifice B-T1 block. The
0.0025 m.
Variable Orifice T1-T block. The
0.0025 m.
Ports The block has the following ports:
P
Hydraulic conserving port associated with the pressure supply
line inlet.
T
Hydraulic conserving port associated with the return line
connection.
A
Hydraulic conserving port associated with the actuator connection
port.
2-72
B
Hydraulic conserving port associated with the actuator connection
port.
S
Physical signal port to control spool displacement.
See Also 4-Way Directional Valve
4-Way Directional Valve A
4-Way Directional Valve B
4-Way Directional Valve D
4-Way Directional Valve E
4-Way Directional Valve F
4-Way Directional Valve G
4-Way Directional Valve H
4-Way Directional Valve K
4-Way Directional Valve C
6-Way Directional Valve A
2-73
4-Way Directional Valve D
Purpose Simulate configuration D of hydraulic continuous 4-way directional
valve
Library Directional Valves
Description The 4-Way Directional Valve D block simulates a configuration of
hydraulic continuous 4-way directional valve. Ports A and B are
connectedtoportPintheleftvalveposition. Intherightposition,
port P is connected to port A, w hile port B is connected to port T. All
connections are blocked in neutral position. The fluid is pumped in the
valve through the inlet line P and is distributed between two outside
hydraulic lines A and B (usually connected to a double-acting actuator)
and the return line T. The block has four hydraulic connections,
corresponding to inlet port (P), actuator ports (A and B), and return port
(T), and one physical signal port connection (S), which controls the spool
position. The block is built of four Variable Orifice b locks, connected as
showninthefollowingdiagram.
2-74
4-Way Directional Valve D
All Variable Orifice blocks are controlled by the same position
signal, provided through the physical signal port S, but the Orifice
orientation parameter in the block instances is set in such a way that
positive signal at port
diagram (orifices P-A2 and P-B ) and closes the orifices colored yellow
(orifices P-A1 and B-T). As a result, the openings of the orifices are
computed as follows:
hh x
=−
PA PA110
=+
hh x
PA PA220
=+
hh x
PB PB
hh x
BT BT
0
=−
0
where
S opens the orifices colored blue in the block
h
h
h
h
h
h
h
h
x
PA1
PA2
PB
BT
PA10
PA20
PB0
BT0
Orifice opening for the Variable Orifice P-A1 block
Orifice opening for the Variable Orifice P-A2 block
Orifice opening for the Variable Orifice P-B block
Orifice opening for the Variable Orifice B-T block
Initial opening for the Variable Orifice P-A1 block
Initial opening for the Variable Orifice P-A2 block
Initial opening for the Variable Orifi ce P-B block
Initial opening for the Variable Orifi ce B-T block
Control member displacement from initial position
For information on the block parameterization options, basic parameter
descriptions, assumptions and limitations, global and restricted
parameters, see the 4 -W ay Directional V alve block r eference page.
2-75
4-Way Directional Valve D
Dialog
Box a nd
Parameters
The block dialog box contains two tabs:
• “Basic Parameters” on page 2-76
• “Initial Openings” on p age 2-77
Basic Parameters
See the documentation for the Basic Parameters tab of the 4-Way
Directional Valve block for parameter descriptions and default values.
2-76
Initial Openings
4-Way Directional Valve D
OrificeP-A1initialopening
Initial opening for the
parameter can be positive (underlapped orifice), negative
Variable Orifice P-A1 block. The
2-77
4-Way Directional Valve D
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
OrificeP-A2initialopening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Orifice P-B initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
Orifice B-T initial opening
Initial opening for the
parameter can be positive (underlapped orifice), negative
(overlapped orifice), or equal to zero for zero lap configuration.
The default value is
-0.0025 m.
Variable Orifice P-A2 block. The
-0.0025 m.
Variable Orifice P-B block. The
-0.0025 m.
Variable Orifice B-T block. The
-0.0025 m.
Ports The block has the following ports:
P
Hydraulic conserving port associated with the pressure supply
line inlet.
T
Hydraulic conserving port associated with the return line
connection.
A
Hydraulic conserving port associated with the actuator connection
port.
B
Hydraulic conserving port associated with the actuator connection
port.
2-78
S
Physical signal port to control spool displacement.
See Also 4-Way Directional Valve
4-Way Directional Valve A
4-Way Directional Valve B
4-Way Directional Valve C
4-Way Directional Valve E
4-Way Directional Valve F
4-Way Directional Valve G
4-Way Directional Valve H
4-Way Directional Valve K
6-Way Directional Valve A
4-Way Directional Valve D
2-79
4-Way Directional Valve E
Purpose Simulate configuration E of hydraulic continuous 4-way directional
valve
Library Directional Valves
Description The 4-Way Directional Valve E block simulates a configuration o f
hydraulic continuous 4-way directional valve. Ports A and B are
connected to port P in the right valve position. In the left position,
port P is connected to port B, w hile port A is connected to port T. All
connections are blocked in neutral position. The fluid is pumped in the
valve through the inlet line P and is distributed between two outside
hydraulic lines A and B (usually connected to a double-acting actuator)
and the return line T. The block has four hydraulic connections,
corresponding to inlet port (P), actuator ports (A and B), and return port
(T), and one physical signal port connection (S), which controls the spool
position. The block is built of four Variable Orifice b locks, connected as
showninthefollowingdiagram.
2-80
ariable Orifice blocks are controlled by the same position
All V
nal, provided through the physical signal port S, but the Orifice
sig
entation parameter in the block instances is set in such a way that
ori
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