DESC:TECHNICAL FIELD
[0001] The present disclosure relates to the technical field of valves. In
particular, the present disclosure relates to an externally operated valve for filling
and exhausting operation, such as for inflating and deflating tyres of a vehicle
5 through a central tyre inflation system.

BACKGROUND
[0002] Background description includes information that may be useful in
understanding the present invention. It is not an admission that any of the
10 information provided herein is prior art or relevant to the presently claimed
invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Valves for filling and exhausting a fluid into/ from a container to
maintain pressure in the container are extensively used. For example, Central tyre
inflation systems (CTIS), which are extensively used in many off-road transport
15 operations, such as military vehicles, mining and construction vehicles, and
agriculture vehicles, use such valves to provide control over the air pressure in
each tyre as a way to improve performance on different surfaces. For example,
lowering the air pressure in a tyre creates a larger area of contact between the tyre
and the ground and makes driving on softer ground much easier. It also does less
20 damage to the surface. This is important on work sites and in agricultural fields.
By giving the driver direct control over the air pressure in each tyre,
maneuverability is greatly improved. Another function of the CTIS is to maintain
pressure in the tyres if there is a slow leak or puncture. In this case, the system
controls inflation automatically based on the selected pressure the driver has set or
25 taking into account speed of the vehicle. Besides above advantages, CTIS also
extends truck, tyre, and drive train life, by significantly reducing vibration and
shock loading.
[0004] A typical CTIS includes a pneumatic control unit (also known as
pressure control unit), a wheel valve located at each wheel and pneumatically
30 coupled to the pneumatic control unit, an electronic control unit (ECU) that
monitors the pressure in each tyre and sends command to the pneumatic control

3

unit, which directly controls the wheel valves and air system for inflating or
deflating the individual tyres depending on requirement. There is also an operator
control panel that is operatively coupled to the electronic control unit and allows
the driver to select tyre-pressure modes to match current conditions.
5 [0005] The wheel valve enables on-demand inflation and deflation of the tyres
by connecting the tyres to the pneumatic control unit when the CTIS actively
measuring or changing tyre pressure. When not inflating or deflating the tyre, the
wheel valve isolates the tyre from the system. Conventional wheel valves are
based on a diaphragm, which is prone to aging, affecting proper functioning of the
10 wheel valve. Therefore, conventional wheel valves are required to be periodically
examined for need to replace them or even replaced after certain time to prevent
failure without warning, thereby resulting in downtime of the vehicle and
additional expenses.
[0006] Also, conventional wheel valves work on the principle of signaling the
15 wheel valve with low flow rate of exhaust and high flow rate of exhaust or low
pressure and high pressure signal, due to which the rate of exhaust is a constrain,
resulting in delays in changing of pressure from higher level to lower level.
[0007] Therefore, there is a requirement of an improved wheel valve that
solves the above stated problem and provides a faster exhaust rates, thereby
20 improving functionality of the wheel valve.
[0008] All publications herein are incorporated by reference to the same
extent as if each individual publication or patent application were specifically and
individually indicated to be incorporated by reference. Where a definition or use
of a term in an incorporated reference is inconsistent or contrary to the definition
25 of that term provided herein, the definition of that term provided herein applies
and the definition of that term in the reference does not apply.
[0009] In some embodiments, the numbers expressing quantities of
ingredients, properties such as concentration, reaction conditions, and so forth,
used to describe and claim certain embodiments of the invention are to be
30 understood as being modified in some instances by the term “about.”
Accordingly, in some embodiments, the numerical parameters set forth in the

4

written description and attached claims are approximations that can vary
depending upon the desired properties sought to be obtained by a particular
embodiment. In some embodiments, the numerical parameters should be
construed in light of the number of reported significant digits and by applying
5 ordinary rounding techniques. Notwithstanding that the numerical ranges and
parameters setting forth the broad scope of some embodiments of the invention
are approximations, the numerical values set forth in the specific examples are
reported as precisely as practicable. The numerical values presented in some
embodiments of the invention may contain certain errors necessarily resulting
10 from the standard deviation found in their respective testing measurements.
[0010] As used in the description herein and throughout the claims that
follow, the meaning of “a,” “an,” and “the” includes plural reference unless the
context clearly dictates otherwise. Also, as used in the description herein, the
meaning of “in” includes “in” and “on” unless the context clearly dictates
15 otherwise.
[0011] The recitation of ranges of values herein is merely intended to serve as
a shorthand method of referring individually to each separate value falling within
the range. Unless otherwise indicated herein, each individual value is incorporated
into the specification as if it were individually recited herein. All methods
20 described herein can be performed in any suitable order unless otherwise
indicated herein or otherwise clearly contradicted by context. The use of any and
all examples, or exemplary language (e.g. “such as”) provided with respect to
certain embodiments herein is intended merely to better illuminate the invention
and does not pose a limitation on the scope of the invention otherwise claimed.

25 No language in the specification should be construed as indicating any non-
claimed element essential to the practice of the invention.

[0012] Groupings of alternative elements or embodiments of the invention
disclosed herein are not to be construed as limitations. Each group member can be
referred to and claimed individually or in any combination with other members of
30 the group or other elements found herein. One or more members of a group can be
included in, or deleted from, a group for reasons of convenience and/or

5

patentability. When any such inclusion or deletion occurs, the specification is
herein deemed to contain the group as modified thus fulfilling the written
description of all Markush groups used in the appended claims.

5 OBJECTS OF THE INVENTION
[0013] A general object of the present disclosure is to overcome the
drawbacks of conventional valves for filling and exhausting a gas into/from a
container, such as wheel valves used with Central Tyre Inflation System for
inflating and deflating tyres.
10 [0014] An object of the present disclosure is to provide a valve for filling and
exhausting a gas into/from a container that does not have a diaphragm.
[0015] Another object of the present disclosure is to provide a valve that can
be actuated both for filling and exhausting a gas into/from a container by an
external gas signal.
15 [0016] Another object of the present disclosure is to provide an improved
valve for filling and exhausting a fluid into/from a container that requires reduced
maintenance.
[0017] Yet another object of the present disclosure is to provide a valve that is
cost effective.
20 [0018] Yet another object of the present disclosure is to provide a valve that
has a higher exhaust flow rate and thus enables a faster change of pressure in the
container.

SUMMARY
25 [0019] Aspects of the present disclosure relate to a valve for filling /
exhausting a gas into/from a container. In particular, the present disclosure
provides a valve that functions to allow filling and exhausting of a container by an
external gas signal from a pressure control unit (PCU).
[0020] In an aspect, the disclosed valve for filling / exhausting a gas into/from
30 a container includes a valve body having an inlet port for coupling to a PCU, an
outlet port coupled to the container, a cylindrical bore, a connecting chamber

6

located at a lower end of the bore and a valve seat at a junction of the bore and the
connecting chamber. The inlet port is in fluidic communication with the bore at
the lower end of the bore and the outlet port is in fluidic communication with the
connecting chamber.
5 [0021] The valve includes an upper piston configured for translatory motion
in the bore and biased in the downward direction.
[0022] The valve further includes a lower piston configured below the upper
piston for translatory motion in the bore and defining a lower chamber that is in
fluidic communication with the inlet port. The upper piston and the lower piston
10 define a middle chamber therebetween. A lower end of the lower piston is
configured to close the valve seat when the lower piston is moved to downward
position.
[0023] In an embodiment, the lower piston may be free floating in the bore
under upward and downward forces due to pressure in the middle chamber and
15 the lower chamber. In an alternate embodiment, depending on functional
requirements, the lower piston may be biased in upward direction.
[0024] In an aspect, the valve includes an orifice fluidically connecting the
lower chamber to the middle chamber. The orifice may be configured to fill the
middle chamber in a gradual manner such that the pressure in the middle chamber
20 equalizes with the pressure in the lower chamber after a time gap. The orifice may
be located in any of the lower piston or the body.
[0025] In an aspect, the diameters of the bore and the upper piston, the size of
the orifice and the biasing force on the upper piston are configured such that when
pressure at the inlet pressure is increased by the pressure control unit at a rate
25 above a predefine pressure change rate by fast filling the gas, pressure in the
middle chamber is not able to increase at the same rate, resulting in pressure
difference between the lower chamber and the middle chamber to move the lower
piston up to open the valve seat.
[0026] In another aspect, when pressure at the inlet pressure is dropped by the
30 pressure control unit at a rate above the predefine pressure change rate by fast

7

exhausting the gas, the lower piston moves down to close the valve seat due to
pressure in the middle chamber not able drop at the same rate.
[0027] After opening of the valve seat, the orifice allows pressure in the
middle chamber to gradually increase to become equal to pressure of the lower
5 chamber causing the lower piston to float. Now, using the pressure control unit,
increase in pressure may be maintained at a rate above the predefine pressure
change rate to keep the valve seat open, which happens due to inability of the
orifice to fill the middle chamber at the same rate and resultant upward force on
the lower piston. This allows filling of the container
10 [0028] Further, after opening of the valve seat, exhausting the container by the
pressure control unit to maintain drop in pressure at a rate below the predefine
pressure change rate keeps the valve set open due to orifice maintaining equal
pressure in the middle chamber and the lower chamber, thereby allowing
exhausting of the container.
15 [0029] As can be appreciated, the predefined pressure change rate is related to
flow rate of the gas through the orifice in the lower piston under a pressure
difference between the middle chamber and the lower chamber.
[0030] In an embodiment, the valve body may include a cylindrical upper
bore located concentric to the bore at an upper end of the bore. The upper piston
20 may be a stepped piston having a larger diameter lower portion that is
accommodated in the bore and a smaller diameter upper portion that is
accommodated in the upper bore to define a top chamber. The upper piston and
the lower piston may be configured to fluidically connect the top chamber to the
connecting chamber such that the top chamber is maintained at container pressure
25 to supplement the biasing force on the valve seat through the upper piston.
[0031] In an embodiment, to facilitate fluidic connectivity between the top
chamber and the connecting chamber, the upper piston and the lower piston may
be telescopically arranged with a lower portion of the upper piston being slidingly
and sealingly configured within a cavity at an upper end of the lower piston.
30 [0032] In an embodiment, the upper piston may include a longitudinal first
hole fluidically connecting the top chamber to a lower end of the upper piston,

8

and the lower piston may include a longitudinal second hole fluidically
connecting the top chamber to the connecting chamber through the first hole to
fluidically connect the top chamber to the connecting chamber.
[0033] In an embodiment, the lower piston may include a mholder fixed at the
5 lower end of the lower piston and projecting downward into the connecting
chamber, and the second hole that fluidically connects the top chamber to the
connecting chamber through the first hole may be located in the mholder. Thus,
balancing any pressure load at the valve seat and thus assuring closed condition of
the valve at any pressure variation in the container.
10 [0034] In an embodiment, the lower piston may further include a ventilteller
fixed to the mholder. The ventilteller and the mholder may be configured to close
the valve seat when the lower piston is moved to downward position.
[0035] The upper piston may be biased in the downward direction by a top
spring provided between the upper piston and the upper end of the bore.
15 [0036] The lower piston, when biased in upward direction, may be biased by a
bottom spring provided between the lower piston and the lower end of the bore.
[0037] In an embodiment, the upper piston and the lower piston may be
arranged slidablly within the bore of the valve body such that the translatory
motion is guided by the bore.
20 [0038] In an alternate embodiment, any or both of the upper piston and the
lower piston may be configured as a diaphragm. In which case, the orifice may be
provided in the corresponding diaphragm or on a body that supports the
corresponding diaphragm.
[0039] Various objects, features, aspects and advantages of the inventive
25 subject matter will become more apparent from the following detailed description
of preferred embodiments, along with the accompanying drawing figures in which
like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
30 [0040] The accompanying drawings are included to provide a further
understanding of the present disclosure, and are incorporated in and constitute a

9

part of this specification. The drawings illustrate exemplary embodiments of the
present disclosure and, together with the description, serve to explain the
principles of the present disclosure.
[0041] FIG. 1 illustrates an exemplary cross sectional view of the proposed
5 wheel valve, in accordance with embodiments of the present disclosure.
[0042] FIGs. 2A and 2B illustrate the sectional view of the proposed wheel
valve showing functioning of the wheel valve during inflation, in accordance with
embodiments of the present disclosure.
[0043] FIG. 3 illustrates the sectional view of the proposed wheel valve
10 showing an upper piston and a lower piston of the wheel valve moving relative to
each other, in accordance with embodiments of the present disclosure.
[0044] FIGs. 4A and 4B illustrate the sectional view of the proposed wheel
valve showing functioning of the wheel valve during deflation, in accordance with
embodiments of the present disclosure.
15
DETAILED DESCRIPTION
[0045] The following is a detailed description of embodiments of the
disclosure depicted in the accompanying drawings. The embodiments are in such
detail as to clearly communicate the disclosure. However, the amount of detail
20 offered is not intended to limit the anticipated variations of embodiments; on the
contrary, the intention is to cover all modifications, equivalents, and alternatives
falling within the spirit and scope of the present disclosure as defined by the
appended claims.
[0046] Each of the appended claims defines a separate invention, which for
25 infringement purposes is recognized as including equivalents to the various
elements or limitations specified in the claims. Depending on the context, all
references below to the "invention" may in some cases refer to certain specific
embodiments only. In other cases it will be recognized that references to the
"invention" will refer to subject matter recited in one or more, but not necessarily
30 all, of the claims.

10

[0047] Various terms are used herein. To the extent a term used in a claim is
not defined, it should be given the broadest definition persons in the pertinent art
have given that term as reflected in printed publications and issued patents at the
time of filing.
5 [0048] Embodiments explained herein relate to a valve that functions to allow
filling and exhausting of a gas into/from a container by an external gas signal
from a pressure control unit (PCU). A most common application of the disclosed
valve is in vehicles for controlling air pressure in a tyre of the vehicle by an
external air signal from a PCU of centralized tyre inflation system (CITS) of the
10 vehicle.
[0049] It is to be appreciated that while the embodiments of the present
disclosure have been described with reference to functionality of inflating and
deflating a tyre of a vehicle, and accordingly term wheel valve has been used for
the proposed valve along with other terms related to its application on vehicles,
15 the inventive concept of the present disclosure can as well be used for other
applications, such as in process industry for filling and exhausting a gaseous fluid
into/from a container to maintain a desired pressure in the container, and all such
applications are well within the scope of the present application without any
limitations whatsoever.
20 [0050] The disclosed wheel valve works based on a middle chamber
configured between an upper piston and a lower piston, which is fluidically
coupled through an orifice to an inlet port of the valve. The inlet port of the valve
is coupled to the PCU of the CTIS and receives the external air signal. The orifice
is configured to fill the middle chamber in a gradual manner such that the pressure
25 in the middle chamber equalizes with the pressure signal applied at the inlet port
after a time gap.
[0051] The upper piston is biased in a downward direction to push the lower
piston so that the lower piston closes a valve seat in a passage from the inlet port
to the outlet port. When, as a result of the air signal at the inlet port in the form of
30 increase in pressure at a rate above a predefine pressure change rate by fast filling
the air, pressure in the middle chamber is not able to increase at the same rate,

11

resulting in pressure difference between the lower chamber and the middle
chamber to move the lower piston up to open the valve seat. As pressure in the
middle chamber increases due to inflow of air through the orifice, the upper piston
gets supported by the air pressure in the middle chamber, thereby allowing the
5 lower piston to float and allow inflation or deflation of the tyre by the PCU by
modulating rate of change of pressure at the inlet port.
[0052] With the valve seat open, inflation or deflation of the corresponding
tyre can be done based on controlled change of pressure by the coupled PCU. For
example, while inflating the tyre, rate of inflow of air is maintained such that rate
10 of increase in pressure at the inlet port is higher than a predefined pressure change
rate, which predefined pressure change rate is selected such that the orifice cannot
keep pace to replenish air pressure in the middle chamber, thereby keeping the
valve open. Likewise, while deflating the tyre, rate of exhaust of air is maintained
such that rate of decrease in pressure at the inlet port is lower than the predefined
15 pressure change rate such that the orifice is able to keep pace to remove air
pressure from the middle chamber to keep the valve open.
[0053] When inflating or deflating of the tyre is to be stopped, such as after
reaching a target pressure, the PCU can exhaust air from the inlet port at a fast
rate such that rate of drop in pressure is above the predefine pressure change rate.
20 On which, the lower piston moves down to close the valve seat due to pressure in
the middle chamber not able to drop at the same rate.
[0054] In an embodiment, the valve may also include a top chamber configure
above the upper piston, which is in fluidic communication with the outlet port.
The tyre pressure in the top chamber acts on the upper piston to supplement the
25 downward biasing force on the upper piston and in turn on the lower piston to
normally keep the valve seat closed.
[0055] It is to be appreciated that while the embodiments of the present
application have been described based on pistons, an upper piston and a lower
piston, which are slidablly configured guided within the bore of a valve body, it is
30 possible to implement the inventive concept of the present application by using a
diaphragm for any or both of the upper piston and a lower piston with the orifice

12

provided on the diaphragm that replaces the lower piston, or any other part, such
as a body, that supports the diaphragm, to provide fluidic communication between
the lower chamber and the intermediate chamber, and all such variations are well
within the scope of the present invention without any limitation whatsoever.
5 Accordingly, the generic term ‘piston’ used with the terms upper piston and the
lower piston is to be interpreted as a component configured within the bore of the
valve body for translatory linear motion along an axis of the bore, and it does not
necessarily mean a component that is slidablly configured guided in the bore.
[0056] Referring to FIG. 1, where a sectional view of an embodiment the
10 proposed wheel valve 100 for central tyre inflation systems having the upper
piston and the lower piston guided in the bore of the valve body is disclosed, the
wheel valve 100 can include a valve body 102 having an inlet port 110, an outlet
port 112, a cylindrical piston bore 104 Also referred simply as bore 104 and the
two terms used interchangeably hereinafter), a connecting chamber 108 located at
15 a lower end of the piston bore 104 and a valve seat 128 at a junction of the piston
bore 104 and the connecting chamber 108. The inlet port 110 can be in fluidic
communication with the piston bore 104 at the lower end of the piston bore 104
and the outlet port 112 can be in fluidic communication with the connecting
chamber 108.
20 [0057] The inlet port 110 can be configured for coupling to a PCU of the
CTIS, and the outlet port 112 can be configured for coupling to a tyre of the
vehicle.
[0058] An upper piston 114 can be configured for translatory motion in the
piston bore 104 and can be biased in the downward direction by a top spring 138
25 that can be provided between the upper piston 114 and the upper end of the piston
bore 102.
[0059] The wheel valve 100 can further includes a lower piston 124
configured below the upper piston 114 for translatory motion in the piston bore
104.
30 [0060] In an embodiment, the lower piston 124 may be freely floating in the
piston bore 102 under air pressure from below and above. In an alternate

13

embodiment, depending on functional requirements, the lower piston 124 can be
biased in upward direction by a bottom spring 140, which can be provided
between the lower piston 124 and the lower end of the piston bore 102. The lower
piston 124 defines a lower chamber 132 in the piston bore 104 located below the
5 lower piston 124, which can be in fluidic communication with the inlet port 110.
A lower end of the lower piston 124 can be configured to close the valve seat 128
when the lower piston 124 is moved to downward position.
[0061] Coaxial arrangement of the upper piston 114 and the lower piston 124
within the piston bore 104 defines a middle chamber 130 located between the
10 upper piston 114 and the lower piston 124.
[0062] In an embodiment, the lower piston 124 can include an orifice 142
fluidically connecting the lower chamber 132 to the middle chamber 130. The
orifice can be configured to allow passage of air from the lower chamber 132 to
the middle chamber 130, or from the middle chamber 130 to the lower chamber
15 132 depending on pressure difference between the two, in a gradual manner such
that the pressure in the middle chamber 130 equalizes with the pressure in the
lower chamber 132 after a time gap.
[0063] It is to be appreciated that while the exemplary illustration in the
figures show the orifice 142 to be configured on the lower piston 124, it is
20 possible to have the orifice 142 in the body 102 such that it fluidically connects
the middle chamber 130 and the lower chamber 132 under all possible positions
of the upper piston 114 and the lower piston 124.
[0064] The diameters of the piston bore 104 and diameters of the upper piston
and the lower piston configure in the piston bore 104, the size of the orifice and
25 the biasing forces on the upper piston 114 and the lower piston 124, if biased by
the bottom spring 140, can be configured such that when an air pressure above a
predefined pressure value is applied at the inlet port 110, the applied air pressure
in the lower chamber 132 acting on the lower piston 124, can overcome the
downward force and pushes the lower piston 124 and the upper piston 114 upward
30 to open the valve seat 128. The orifice 142 can allow air pressure in the middle
chamber 130 to gradually increase reaching a stage such that air pressure in the

14

middle chamber 130 acting on the upper piston 114 applies an upward force on
the upper piston that overcomes the downward force. With the upward force and
the downward force on the upper piston 114 being balanced, the lower piston 124
can float, as shown in FIG. 3. This can keep the valve seat 128 in the open
5 condition for the tyre to be inflated or deflated by modulating rate of change of
pressure at the inlet port 110 by the PCU of the CTIS.
[0065] With the valve seat 128 open, inflation or deflation of the
corresponding tyre can be done based on controlled change of pressure at the inlet
port 110 by the coupled PCU. For example, while inflating the tyre, rate of inflow
10 of air is maintained such that rate of increase in pressure at the inlet port 110 is
higher than the predefined pressure change rate, which predefined pressure
change rate is selected such that the orifice 142 cannot keep pace to replenish air
pressure in the middle chamber 130, thereby keeping the valve seat 128 open.
Likewise, while deflating the tyre, rate of exhaust of air from the inlet port 110
15 can be maintained such that rate of decrease in pressure at the inlet port 110 is
lower than the predefined pressure change rate so that the orifice 142 is able to
keep pace to remove air pressure from the middle chamber 130 to keep the valve
seat 128 open.
[0066] When deflating of the tyre is required to be stopped, such as after
20 reaching a target pressure, the PCU can exhaust air from the inlet port 110 at a
fast rate such that rate of drop in pressure is above the predefine pressure change
rate. On which, the lower piston moves down to close the valve seat 128 due to
pressure in the middle chamber 130 not able to drop at the same rate.
[0067] In an embodiment, in order to supplement downward force on the
25 upper piston 114 from the top spring 138, the valve body 102 and the upper piston
114 can be configured to provide a top chamber 120 that is in fluidic
communication with the .
[0068] To create a top chamber 120, the valve body can include a cylindrical
upper piston bore 106 located concentric to the piston bore 104 at an upper end of
30 the piston bore 104, and the upper piston 114 can be a stepped piston having a
larger diameter lower portion 116 that is accommodated in the piston bore 104

15

and a smaller diameter upper portion 118. The smaller diameter upper portion 118
can be accommodated in the upper piston bore 106 creating the top chamber 120
located in the above the upper portion 118 of the upper piston 114.
[0069] To provide fluidic connectivity of the top chamber 120 with the
5 connecting chamber 108, the upper piston 114 can include a longitudinal first hole
122 fluidically connecting the top chamber 120 to a lower end of the upper piston
114. The lower piston 124 can include a second hole 144 that can fluidically
connect the top chamber 120 to the connecting chamber 108 through the first hole
122 such that the top chamber 120 is maintained at tyre pressure. The upper piston
10 114 and the lower piston 124 can be telescopically arranged with a lower portion
of the upper piston 114 being slidingly and sealingly configured within a cavity
126 at an upper end of the lower piston 124 to provide the fluidic connectivity by
the combination of the first hole 122 and the second hole 144.
[0070] The pressure in the top chamber 120 can act on the smaller diameter
15 portion 118 of the upper piston 114 to supplement the downward biasing force on
the upper piston 114. The upper piston 114, when in contact with the lower piston
124 at its lower end can push the lower piston 124 to close the valve seat 128.
[0071] In an embodiment, the lower piston 124 can include a mholder 134
fixed at the lower end of the lower piston 124 that projects downward into the
20 connecting chamber 108. The second hole 144 can be located in the mholder.
[0072] In an embodiment, the lower piston 124 can further include a
ventilteller 136 fixed to the mholder 134. The ventilteller 136 and the mholder
134 may be configured to close the valve seat 128 when the lower piston when the
lower piston 124 is moved to downward position.
25 [0073] It is to be appreciated that while the exemplary embodiments shown in
FIG. 1, as well as in subsequent figures, show the upper piston 114 and the lower
piston 124 slidablly configured guided within the bore 104 of the valve body 102,
it is possible to implement the inventive concept of the present application by
using a diaphragm for any or both of the upper piston 114 and the lower piston
30 124 with the orifice 142 provided on the corresponding diaphragm or on any
other part, such as a body that supports the corresponding diaphragm.

16

[0074] FIGs. 2A and 2B show functioning of the wheel valve during inflation,
wherein arrows in FIG. 2A show the air pressure being applied to the inlet port
110, and FIG. 2B shows the applied pressure moving to the tyre through the outlet
port 112 to inflate the tyre. While inflating the tyre, rate of inflow of air is
5 maintained such that rate of change of pressure is higher than a predefined
pressure change rate, which the orifice 142 cannot keep pace to replenish air
pressure in the middle chamber 130 to keep the valve seat 128 open, and likewise,
while deflating the tyre, rate of exhaust of air is maintained such that rate of
change of pressure is lower than the predefined pressure change rate which the
10 orifice 142 is able to keep pace with by removing air from the middle chamber
130 to maintain equal pressure on both sides of the lower piston 124, which keeps
the valve seat 128 open.
[0075] As can be appreciated, the predefined pressure change rate is related to
flow rate of air through the orifice 142 under a pressure difference between the
15 middle chamber 130 and the lower chamber 132. Therefore changing the orifice
size can result in increasing or decreasing the predefined pressure change rate
value, thereby giving design control over the rate at which the tyre can be inflated
and deflated.
[0076] FIGs. 4A and 4B show functioning of the wheel valve during
20 deflation, wherein arrows in FIG. 4A show the air pressure from the tyre acting on
the outlet port 112, and FIG. 4B shows the air from the tyre moving to the inlet
port 110 to deflate the tyre. During deflation, initially a pressure pulse is given in
the lower chamber 132 by PCU, which opens the valve seat 128. Thereafter, PCU
can gradually allow air from the tyre to exhaust at a rate such that rate of pressure
25 drop that is lower than the predefined pressure change rate. Due to lower pressure
drop rate, air from the middle chamber 130 is able to flow out through the orifice
142 in lower piston 124 thereby reducing the air pressure in the middle chamber
130 at about the same rate. Reduction in the air pressure in the middle chamber
130 in synchronization with pressure in the lower chamber 132 keeps the lower
30 chamber 132 and middle chamber 130 at around same pressure, thus keeping the
valve seat 128 open.

17

[0077] When exhausting or deflation is required to be stopped, such as after
reaching a target pressure in the tyre, the PCU can stop the flow, which makes
sure that the system is at stable pressure, i.e. pressure in the middle chamber 130
and lower chamber 132 is same. After a stable condition is attained with the tyre
5 pressure being at the target pressure, the PCU can exhaust air through the inlet
port at a rate faster than the predefine pressure change rate, which the orifice 142
is not able to match, resulting in air pressure in the middle chamber 130 to exceed
pressure in the lower chamber 132 and resultant movement of the lower piston
124 downward to close the valve seat 128. Closing of the valve seat 128 chokes
10 supply of further air to the lower chamber 132 generating higher pressure
differential between the middle chamber 130 and the lower chamber 132, which
further affirms the closing of the valve seat 128. As the orifice 142 bleeds out all
the pressure from the middle chamber 130, the downward biasing load of the
upper piston takes over the job of pushing the lower piston 124 down affirming
15 tight shut off.
[0078] Thus, the present disclosure provides a wheel valve for CTIS that
opens to allows inflation or deflation of the corresponding tyre by an external
signal such as by applying air pressure at the inlet port above a predefined
pressure value and inflating or deflating the corresponding tyre at a rate higher or
20 lower that a predefined pressure change rate. The external signal, i.e. the applied
pressure (pressure signal) and the pressure change rate (pressure rate change
signal or simply pressure rate signal), can be applied by the PCU of the CTIS.
After the application of the pressure signal the valve seat of the wheel valve
remains open to allow inflation or deflation by modulating the pressure change
25 rate at the inlet port by the PCU. When the air pressure at the inlet port is reduced
by the PCU below a target pressure value, the valve seat can be closed by
application of another pressure and pressure rate signal from the PCU.
[0079] While the foregoing describes various embodiments of the invention,
other and further embodiments of the invention may be devised without departing
30 from the basic scope thereof. The scope of the invention is determined by the
claims that follow. The invention is not limited to the described embodiments,

18

versions or examples, which are included to enable a person having ordinary skill
in the art to make and use the invention when combined with information and
knowledge available to the person having ordinary skill in the art.

5 ADVANTAGES OF THE INVENTION
[0080] The present disclosure provides a valve that overcomes the drawbacks
of conventional valves for filling and exhausting a fluid into/from a container,
such as wheel valves used with Central Tyre Inflation System for inflating and
deflating tyres.
10 [0081] The present disclosure provides a valve for filling and exhausting a
fluid into/from a container that does not have a diaphragm.
[0082] The present disclosure provides a valve that can be actuated both for
filling and exhausting the fluid by an external gas signal.
[0083] The present disclosure provides an improved valve for filling and
15 exhausting a fluid into/from a container that requires reduced maintenance.
[0084] The present disclosure provides a valve that has a higher exhaust flow
rate and thus enables a faster change of pressure in the container.
[0085] The present disclosure provides a valve that is cost effective. ,CLAIMS:1. A valve for filling and exhausting a gas into/ from a container, the valve
comprising:

5 a valve body having an inlet port coupled to a pressure control unit,
an outlet port coupled to the container, a cylindrical bore, a connecting
chamber located at a lower end of the bore and a valve seat at a junction of
the bore and the connecting chamber, wherein the inlet port is in fluidic
communication with the bore at the lower end of the bore and the outlet

10 port is in fluidic communication with the connecting chamber;

an upper piston configured for translatory motion in the bore and
biased in the downward direction;
a lower piston configured below the upper piston for translatory
motion in the bore defining a lower chamber in fluidic communication
15 with the inlet port, the upper piston and the lower piston defining a middle
chamber therebetween; wherein a lower end of the lower piston is
configured to close the valve seat when the lower piston is moved to a
downward position; and
an orifice fluidically connecting the lower chamber to the middle

20 chamber;

wherein the diameters of the bore and the upper piston, the size of the
orifice and the biasing force on the upper piston are configured such that
when pressure at the inlet pressure is increased by the pressure control unit
at a rate above a predefine pressure change rate by fast filling the gas,
25 pressure in the middle chamber is not able to increase at the same rate,
resulting in pressure difference between the lower chamber and the middle
chamber to move the lower piston up to open the valve seat;
wherein, when pressure at the inlet pressure is dropped by the pressure
control unit at a rate above the predefine pressure change rate by fast
30 exhausting the gas, the lower piston moves down to close the valve seat
due to pressure in the middle chamber not able drop at the same rate.

20

2. The valve as claimed in claim 1, wherein, after opening of the valve seat,
the orifice allows pressure in the middle chamber to gradually increase to
become equal to pressure of the lower chamber causing the lower piston to
float; and wherein maintaining, using the pressure control unit, increase in
5 pressure at a rate above the predefine pressure change rate, keeps the valve
seat open due to inability of the orifice to fill the middle chamber at the
same rate and resultant upward force on the lower piston, thereby allowing
filling of the container
3. The valve as claimed in claim 1, wherein, after opening of the valve seat,
10 exhausting the container by the pressure control unit to maintain drop in
pressure at a rate below the predefine pressure change rate keeps the valve
set open due to orifice maintaining equal pressure in the middle chamber
and the lower chamber, thereby allowing exhausting of the container.
4. The valve as claimed in claim 1, wherein the orifice is located in the
15 lower piston or the body.
5. The valve as claimed in claim 1, wherein the lower piston is free floating
in the bore under upward and downward forces due to pressure in the
middle chamber and the lower chamber.
6. The valve as claimed in claim 1, wherein the lower piston is biased in
20 upward direction by a bottom spring provided between the lower piston

and the lower end of the bore.
7. The valve as claimed in claim 1, wherein orifice is configured to fill the
middle chamber in a gradual manner such that the pressure in the middle
chamber equalizes with the pressure in the lower chamber after a time gap.
25 8. The valve as claimed in claim 1, wherein the valve body includes a
cylindrical upper bore located concentric to the bore at an upper end of the
bore, and the upper piston is a stepped piston having a larger diameter
lower portion that is accommodated in the bore and a smaller diameter
upper portion that is accommodated in the upper bore to define a top
30 chamber, wherein the upper piston and the lower piston are configured to
fluidically connect the top chamber to the connecting chamber such that

21

the top chamber is maintained at container pressure to supplement the
biasing force on the upper piston.
9. The valve as claimed in claim 8, wherein the upper piston and the lower
piston are telescopically arranged with a lower portion of the upper piston
5 being slidingly and sealingly configured within a cavity at an upper end of
the lower piston to facilitate fluidic connectivity between the top chamber
and the connecting chamber.
10. The valve as claimed in claim 9, wherein the upper piston includes a
longitudinal first hole fluidically connecting the top chamber to a lower
10 end of the upper piston, and the lower piston includes a longitudinal
second hole fluidically connecting the top chamber to the connecting
chamber through the first hole to fluidically connect the top chamber to the
connecting chamber.
11. The valve as claimed in claim 10, wherein the lower piston includes a
15 mholder fixed at the lower end of the lower piston and projecting
downward into the connecting chamber, wherein the second hole that
fluidically connects the top chamber to the connecting chamber through
the first hole is located in the mholder.
12. The valve as claimed in claim 11, wherein the lower piston further
20 includes a ventilteller fixed to the mholder, the ventilteller and the mholder
being configured to close the valve seat when the lower piston when the
lower piston is moved to downward position.
13. The valve as claimed in claim 1, wherein the upper piston is biased in the
downward direction by a top spring provided between the upper piston and

25 the upper end of the bore.
14. The valve as claimed in claim 1, wherein the upper piston and the lower
piston are configured slidablly configured within the bore of the valve
body.
15. The valve as claimed in claim 1, wherein any or both of the upper piston
30 and the lower piston are configured as a diaphragm, and the orifice is

22

provided in the corresponding diaphragm or on a body that supports the
corresponding diaphragm.
16. The valve as claimed in claim 1, wherein the valve is a wheel valve and
the container is a tyre of a vehicle, and wherein the wheel valve is used for

5 inflation and deflation of the tyre.