VALVE ASSEMBLY FOR A TANK OF A VEHICLE AND A METHOD OF
CREATING A VACUUM IN THE TANK
TECHNICAL FIELD
[0001] The present teachings generally relate to a valve assembly for a tank of a
vehicle and a method of creating a vacuum in the tank.
BACKGROUND
[0002] Fuel tank valves that function to vent vapors from a fuel tank are known.
Generally, the vapors vent out to a canister that stores and purges the vapors over a period of
time. Vehicle diagnostics can be utilized to detect vapor flow between, for example, the fuel
tank and the canister.
SUMMARY
[0003] The present teachings generally include a valve assembly for a tank of a
vehicle. The valve assembly includes a valve body adapted to be attached to the tank. The
valve body defines a cavity along a longitudinal axis and defines an outlet in fluid
communication with the cavity for venting the tank. The valve assembly also includes a seat
disposed in the cavity of the valve body. The seat separates the cavity into a first cavity
portion and a second cavity portion. The seat defines an aperture along the longitudinal axis
to provide fluid communication between the first and second cavity portions. The valve
assembly further includes a cover device disposed between the seat and the outlet. The cover
device defines at least one hole therethrough. The cover device is movable between a rest
position engaging the seat to minimize fluid communication between the aperture and the
hole and an actuated position spaced from the seat to increase fluid communication between
the aperture and the hole when a vacuum is created in the first cavity portion.
[0004] The present teachings also generally include another valve assembly for a
tank of a vehicle. The valve assembly includes a valve body adapted to be attached to the
tank. The valve body defines a cavity along a longitudinal axis and defines an outlet in fluid
communication with the cavity for venting the tank. The valve assembly also includes a seat
disposed in the cavity of the valve body. The seat separates the cavity into a first cavity
portion and a second cavity portion. The seat includes a platform defining an aperture along
the longitudinal axis to provide fluid communication between the first and second cavity
portions. The valve assembly further includes a cover device disposed between the seat and
the outlet. The cover device defines at least one hole therethrough. The cover device is
movable between a rest position engaging the platform to minimize fluid communication
between the aperture and the hole and an actuated position spaced from the platform to
increase fluid communication between the aperture and the hole when a vacuum is created in
the first cavity portion. The first and second cavity portions have a substantially equal first
pressure when the cover device is in the rest position. The first cavity portion obtains a
second pressure less than the first pressure of the second cavity portion when the vacuum is
created in the first cavity portion which moves the cover device to the actuated position to
increase fluid communication between the first and second cavity portions.
[0005] The present teachings further generally include a method of creating the
vacuum in the tank of the vehicle when performing a diagnostic test. The method includes
providing the valve body adapted to be attached to the tank. The valve body includes the first
cavity portion and the second cavity portion separated by the first seat as discussed above.
The method also includes minimizing flow of gaseous fluid between the hole in the cover
device and the aperture of the seat when the cover device is in the rest position engaging the
seat. The first and second cavity portions each have a substantially equal pressure when the
cover device is in the rest position. The method further includes removing gaseous fluid from
the first cavity portion of the valve body to create the vacuum in the first cavity portion and a
pressure difference between the first and second cavity portions. In addition, the method
includes moving the cover device to the actuated position spaced from the seat in response to
the vacuum creating the pressure difference between the first and second cavity portions.
Furthermore, the method includes increasing flow of the gaseous fluid between the hole in
the cover device and the aperture of the seat when the cover device is in the actuated position
to increase flow of the gaseous fluid between the first and second cavity portions to create the
vacuum in the tank.
[0006] Therefore, the cover device is designed to quickly move to the actuated
position to quickly increase fluid communication through the valve assembly and quickly
create the vacuum in the tank.
[0007] The above features and advantages and other features and advantages of the
present teachings are readily apparent from the following detailed description of the best
modes for carrying out the present teachings when taken in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 is a schematic partial cross-sectional side illustration of a fluid
detection system, with a valve assembly mounted to a tank.
[0009] Figure 2 is a schematic broken cross-sectional perspective view of the valve
assembly, with a cover device in a rest position and a float in a first position.
[0010] Figure 3 is a schematic broken cross-sectional view of the cover device in an
actuated position.
[0011] Figure 4 is a schematic partial exploded view of the cover device.
[0012] Figure 5 is a schematic broken cross-sectional view of another embodiment
of the cover device.
[0013] Figure 6 is schematic flowchart of a method of creating a vacuum in the tank
of Figures 1-5.
DETAILED DESCRIPTION
[0014] Referring to the Figures, wherein like numerals indicate like or
corresponding parts throughout the several views, generally, a fluid detection system 10 for a
vehicle is shown in Figure 1. The fluid detection system 10 can include a valve assembly 12
for a tank 14 of the vehicle, which is generally shown in Figures 1 and 2. In certain
embodiments, the tank 14 can be a fuel tank 14 of the vehicle. Therefore, liquid fluid, such
as fuel can be stored in the tank 14. It is to be appreciated that the valve assembly 12 can be
utilized with tanks 14 other than fuel tanks 14. Therefore, other liquid fluids can be stored in
the tank 14.
[0015] The valve assembly 12 can be internally mounted to the tank 14 or
externally mounted to the tank 14 as shown in Figure 1. For the externally mounted valve
assembly 12, a portion of the valve assembly 12 is disposed inside the tank 14 and another
portion of the valve assembly 12 is disposed outside of the tank 14 as shown in Figure 1. The
features of the valve assembly 12 discussed herein are the same for the internally mounted
valve assembly 12 and the externally mounted valve assembly 12. It is to be appreciated that
other components can be utilized with the internally or externally mounted valve assembly
12, such as for example, with the internally mounted valve assembly 12, a nipple can extend
through the tank 14 to couple the valve assembly 12 inside the tank 14 to outside of the tank
14 and a bracket can support the valve assembly 12 inside the tank 14.
[0016] Generally, the fluid detection system 10 can include a vapor control
structure 16 (see Figure 1) that receives gaseous fluid, such as vapors from the tank 14. The
valve assembly 1 allows the gaseous fluid, such as vapors, that build up in the tank 14 to be
vented out of the tank 14 to the vapor control structure 16. The vapor control structure 16
can store and/or purge the vapors received from the tank 14. Therefore, under certain
conditions, the vapors move or flow from the tank 14 through the valve assembly 12 and into
the vapor control structure 16. It is to be appreciated that the vapor control structure 16 can
be a canister, such as a charcoal canister.
[0017] Continuing with Figure 1, the fluid detection system 10 can include a
vacuum apparatus 18 coupled to the vapor control structure 16 to create a vacuum in the
valve assembly 12 and the tank 14. As such, the vacuum apparatus 18 is in fluid
communication with the tank 14, the valve assembly 12 and the vapor control structure 16.
Therefore, when the vacuum apparatus 18 is actuated, vapors flow from the tank 14, through
the valve assembly 12, through the vapor control structure 16 and into the vacuum apparatus
18. Simply stated, the vacuum apparatus 18 pulls the vapors from the tank 14 and the vapor
control structure 16 to the vacuum apparatus 18. The vacuum apparatus 18 can also purge
the vapors from the tank 14, the valve assembly 12, and the vapor control structure 16. It is
to be appreciated that the vacuum apparatus 18 can be a pump.
[0018] The fluid detection system 10 can also include a controller 20 for actuating
the vacuum apparatus 18 to create the vacuum in the valve assembly 12, and thus the tank 14.
For example, the vacuum apparatus 18 can be activated when it is desirable to check the
vapor flow of the system 10. Therefore, the fluid detection system 10 can determine whether
there is undesirable vapor seepage to the atmosphere through the tank 14, the vapor control
structure 16, the valve assembly 12, and/or fluid tubes 2 1 (see Figure 1) between the tank 14
and the vacuum apparatus 18.
[0019] The fluid detection system 10 can also include one or more sensors 22, such
as a pressure sensor 22, to measure the amount of pressure in the tank 14, in the vapor control
structure 16 and/or in the fluid tubes 2 1 between the tank 14 and the vacuum apparatus 18.
For example, as shown in Figure 1, in one embodiment, the sensor 22 can be mounted in the
tank 14. As another example, also shown in Figure 1, in another embodiment, the sensor 22
can be mounted between the tank 14 and the vapor control structure 16. Generally, when
performing a diagnostic test to the vehicle, the controller 20 is in communication with the
sensor 22; therefore, the sensor 22 signals the controller 20 whether the desired amount of
pressure for the desired amount of time has been obtained. It is to be appreciated that two
sensors 22 are shown in Figure 1 for illustrative purposes only to indicate different locations
that the sensor 22 can be disposed, and therefore, generally, both of these sensors 22 are not
utilized together in this system 10.
[0020] If the desired amount of pressure for the desired amount of time has been
obtained, the vapor flow from the tank 14 to the vacuum apparatus 18 is suitable and the
vehicle passes the diagnostic test. If the desired amount of pressure for the desired amount of
time is not obtained, an undesirable amount of vapors are seeping to the atmosphere through
the system 10 (e.g., vapors seeping through one or more of the tank 14, the vapor control
structure 16, the valve assembly 12, and the fluid tubes 2 1 (see Figure 1) between the tank 14
and the vacuum apparatus 18, etc.), and therefore, the controller 20 activates an indicator in
the vehicle, or an indicator of a stand-alone device in communication with the vehicle, to
indicate that the vehicle did not pass the diagnostic test and the system 10 is ready for
maintenance.
[0021] As such, if the amount of pressure created in the tank 14, the vapor control
structure 16 and the fluid tubes 2 1 between the tank 14 and the vacuum apparatus 18, etc.,
begins to return to atmospheric pressure at a rate greater than a threshold, then an undesirable
amount of vapors are seeping out of the system 10 (e.g., seeping out of one or more of the
tank 14, the vapor control structure 16 and the fluid tubes 2 1 between the tank 14 and the
vacuum apparatus 18, etc.) to the atmosphere, and thus, the system 10 is ready for
maintenance. Therefore, for example, to run the diagnostic test, the vacuum apparatus 18 is
actuated to create the vacuum in the tank 14, the vapor control structure 16 and the fluid tubes
2 1 between the tank 14 and the vacuum apparatus 18; and when the desired amount of
pressure is reached in the tank 14, the vapor control structure 16 and the fluid tubes 2 1
between the tank 14 and the vacuum apparatus 18 by the vacuum, the vacuum apparatus 18
stops creating the vacuum and a timed count-down begins to measure the rate that the tank
14, the vapor control structure 16 and the fluid tubes 2 1 between the tank 14 and the vacuum
apparatus 18 returns to atmospheric pressure.
[0022] Generally, in certain embodiments, the amount of time that the diagnostic
test is performed is from about 8.0 seconds to about 12.0 seconds. Additionally, in certain
embodiments, the amount of pressure created by the vacuum is less than 1.0 pound per square
inch (psi) to about 0.20 psi. In one embodiment, the diagnostic test is performed for 10.0
seconds and the amount of pressure created by the vacuum is 0.25 psi. It is to be appreciated
that the amount of pressure and the amount of time the diagnostic test is performed can be
other values than the examples discussed above. Furthermore, it is to be appreciated that the
threshold discussed above can be any suitable value to indicate whether an undesirable
amount of vapors are seeping to atmosphere through one or more of the tank 14, the vapor
control structure 16 and the fluid tubes 1 between the tank 14 and the vacuum apparatus 18,
etc., to indicate whether the system 10 is ready for maintenance. The threshold will be
obtained (and thus the vehicle will fail the diagnostic test) if, for example, an opening having
a diameter from about 0.50 millimeters or greater is defined in one or more of the tank 14, the
vapor control structure 16 and the fluid tubes 2 1 between the tank 14 and the vacuum
apparatus 18, etc. is in communication with the atmosphere (i.e., the opening is in
communication with the atmosphere).
[0023] The fluid detection system 10 can further include one or more on/off valves
24 between the tank 14 and the vacuum apparatus 18. The on/off valves 24 are in
communication with the controller 20 such that the controller 20 can selectively actuate the
on/off valves 24. Therefore, the controller 20 signals one or more of the on/off valves 24 to
open to allow fluid, such as vapors, to flow therethrough and close to prevent fluid, such as
vapors, from flowing therethrough. The on/off valves 24 can be a purge valve and/or a
solenoid valve, etc. Generally, the fluid detection system 10 utilizes a plurality of on/off
valves 24 as shown in Figure 1. For example, the on/off valve 24 coupled to the vapor
control structure 16 can be actuated to purge the vapor control structure 16 to atmospheric
pressure, and the on/off valve 24 disposed between the vapor control structure 16 and the
vacuum apparatus 18 can be actuated to apply the vacuum generally to the vapor control
structure 16 and the tank 14. For example, the on/off valve 24 coupled to the vapor control
structure 16 is closed during the diagnostic test and the on/off valve 24 between the vapor
control structure 16 and the vacuum apparatus 18 is closed during the diagnostic test such
that the vapors do not escape to the atmosphere through the on/off valves 24. To run the
diagnostic test, the vacuum apparatus 18 is actuated to create the vacuum in the tank 14, the
vapor control structure 16 and the fluid tubes 2 1 between the tank 14 and the vacuum
apparatus 18, etc.; and once the desired amount of pressure is reached by the vacuum, the
vacuum apparatus 18 stops creating the vacuum and both of the on/off valves 24 are closed
and the timed count-down (as discussed above) begins.
[0024] The controller 20, shown schematically in Figure 1, can be embodied as a
digital computer device or multiple such devices in communication with the various
components of the vehicle. For example, as mentioned above, the controller 20 is in
communication with the sensor(s) 22 and the on/off valve(s) 24. Structurally, the controller
20 can include at least one microprocessor 26 along with sufficient tangible, non-transitory
memory 28, e.g., read-only memory (ROM), flash memory, optical memory, additional
magnetic memory, etc. The controller 20 can also include any required random access
memory (RAM), electrically-programmable read only memory (EPROM), a high-speed
clock, analog-to-digital (A/D) and/or digital-to-analog (D/A) circuitry, and any input/output
circuitry or devices, as well as any appropriate signal conditioning and buffer circuitry.
Instructions for executing a method 1000 for creating the vacuum are recorded in the memory
28 and executed as needed via the microprocessor(s) 26.
[0025] Referring to Figure 1, the valve assembly 12 includes a valve body 30
adapted to be attached to the tank 14. Therefore, the valve body 30 can be internally or
externally mounted to the tank 14. For example, as shown in Figure 1, a portion of the valve
body 30 can be disposed inside the tank 14 and another portion of the valve body 30 can be
disposed outside of the tank 14 for the externally mounted embodiment.
[0026] Turning to Figure 2, generally, the valve body 30 defines a cavity 32 along a
longitudinal axis 34 and defines an outlet 36 in fluid communication with the cavity 32 for
venting the tank 14. Therefore, vapors in the tank 14 can be vented through the cavity 32 and
out the outlet 36 to the vapor control structure 16.
[0027] Continuing with Figure 2, the valve assembly 12 further includes a seat 38
disposed in the cavity 32 of the valve body 30 and separating the cavity 32 into a first cavity
portion 40 and a second cavity portion 42. The seat 38 defines an aperture 44 along the
longitudinal axis 34 to provide fluid communication between the first and second cavity
portions 40, 42. Generally, the seat 38 can include a first surface 46 facing the first cavity
portion 40 and a second surface 48 facing the second cavity portion 42. Furthermore, the
aperture 44 is disposed through the first and second surfaces 46, 48.
[0028] In certain embodiments, the seat 38 includes a platform 50 defining the
aperture 44 along the longitudinal axis 34 to provide fluid communication between the first
and second cavity portions 40, 42. In addition, in certain embodiments, the platform 50
includes the first surface 46 facing the first cavity portion 40 and the second surface 48 facing
the second cavity portion 42. Furthermore, in certain embodiments, the seat 38 can include a
protrusion 52 extending from the platform 50 into the second cavity portion 42, with the
protrusion 52 further defining the aperture 44. The seat 38 can be further defined as a first
seat 38 and will be referred to as the first seat 38 for the below discussion.
[0029] Referring to Figures 2-5, the valve assembly 12 also includes a cover device
54 disposed between the first seat 38 and the outlet 36. More specifically, the cover device
54 is disposed in the first cavity portion 40. The cover device 54 defines at least one hole 56
therethrough. Generally, the cover device 54 is movable between a rest position engaging the
first seat 38 to minimize fluid communication between the first and second cavity portions
40, 42 and an actuated position spaced from the first seat 38 to increase fluid communication
between the first and second cavity portions 40, 42 when a vacuum is created in the first
cavity portion 40. More specifically, the cover device 54 is movable between the rest
position engaging the first seat 38 to minimize fluid communication between the aperture 44
and the hole 56 and the actuated position spaced from the first seat 38 to increase fluid
communication between the aperture 44 and the hole 56 when the vacuum is created in the
first cavity portion 40. Specifically, in certain embodiments, the cover device 54 is movable
between the rest position engaging the platform 50 to minimize fluid communication between
the aperture 44 and the hole 56 and the actuated position spaced from the platform 50 to
increase fluid communication between the aperture 44 and the hole 56 when the vacuum is
created in the first cavity portion 40. Therefore, when the vacuum apparatus 18 is actuated,
the vacuum is created in the system 10 (e.g., created in the tank 14, the vapor control
structure 16 and the fluid tubes 2 1 between the tank 14 and the vacuum apparatus 18, etc.),
which pulls the vapors toward the vacuum apparatus 18. Generally, when the vacuum is
initially created, the vacuum is created in the first cavity portion 40 of the valve body 30
which causes the cover device 54 to move to the actuated position such that vapors flow from
the second cavity portion 42 to the first cavity portion 40 to create the vacuum in the second
cavity portion 42 and thus the tank 14. If too much time passes to create the vacuum, the
sensor 22 could falsely determine that the vehicle is ready for maintenance. Therefore, the
cover device 54 is designed to quickly open when the vacuum is created to quickly create the
vacuum in the system 10 which minimize the sensor 22 falsely indicating that the vehicle is
ready for maintenance. For example, when running the diagnostic test, as soon as the
vacuum is created in the first cavity portion 40, the cover device 54 can instantaneously open
(move to the actuated position). As another example, when running the diagnostic test, the
cover device 54 can open (move to the actuated position) from about 1.0 seconds to about 2.0
seconds after the vacuum is created in the first cavity portion 40. The rest position of the
cover device 54 is shown in Figures 2 and 5 and the actuated position of the cover device 54
is shown in Figure 3.
[0030] Continuing with Figures 2-5, the cover device 54 can include a plate 58
movable between the rest and actuated positions to selectively engage the first seat 38. In
certain embodiments, the plate 58 can selectively engage the platform 50. Furthermore, in
certain embodiments, the plate 58 can selectively engage the first surface 46 of the first seat
38 or the first surface 46 of the platform 50. In certain embodiments, the plate 58 is formed
of a polymeric material. One suitable polymeric material is plastic. It is to be appreciated
that the plate 58 can be formed of any suitable polymeric material or any other suitable
material.
[0031] Generally, the plate 58 can define the at least one hole 56. In certain
embodiments, the at least one hole 56 is further defined as a plurality of holes 56 spaced from
each other, with the plate 58 defining the holes 56. The plate 58 can include a first side 60
and a second side 62 opposing each other, with the first and second sides 60, 62 of the plate
58 defining the holes 56 therethrough. Generally, the second side 62 of the plate 58 faces the
first surface 46 of the first seat 38. It is to be appreciated that the holes 56 can be any suitable
configuration and location.
[0032] The cover device 54 can also include a diaphragm 64 attached to the plate 58
and the valve body 30 such that the plate 58 and the diaphragm 64 cooperate to cover the first
seat 38, and more specifically, cover the platform 50. Generally, the diaphragm 64 is at least
partially movable with the plate 58 between the rest and actuated positions. The diaphragm
64 is spaced from the first surface 46 when the plate 58 is in the rest and actuated positions.
In other words, the diaphragm 64 remains spaced from the first surface 46. Generally, as best
shown in Figures 2, 3 and 5, the diaphragm 64 surrounds the plate 58, with an outer edge 66
of the diaphragm 64 attached to the valve body 30 and an inner edge 68 of the diaphragm 64
attached to the plate 58. When the vacuum is applied to the first cavity portion 40, the
vacuum acts on the large surface area of the diaphragm 64 which moves the plate 58 to the
actuated position. The large surface area of the diaphragm 64 assists to quickly move the
cover device 54 to the actuated position when the vacuum is applied to the first cavity portion
40.
[0033] The diaphragm 64 is flexible to allow movement of the plate 58 between the
rest and actuated positions. Therefore, in certain embodiments, the diaphragm 64 is formed
of an elastomer. One suitable elastomer is rubber. It is to be appreciated that the diaphragm
64 can be formed of any suitable elastomer or material. It is to also be appreciated that the
plate 58 and the diaphragm 64 can be integrally formed to each other or formed of one piece.
[0034] In certain embodiments, optionally, the first surface 46 of the first seat 38
defines a notch 70 (see Figures 2-4) adjacent to the aperture 44 to provide fluid
communication between the first and second cavity portions 40, 42 to substantially equalize
small pressure differences between the first and second cavity portions 40, 42 when the cover
device 54 is in the rest position. In other words, when the plate 58 engages the aperture 44,
the notch 70 allows a small amount of vapors to communicate between the first and second
cavity portions 40, 42 such that small pressure differentials between the first and second
cavity portions 40, 42 can be equalized. Therefore, these small pressure differences between
the first and second cavity portions 40, 42 are less than the pressure differences which cause
the cover device 54 to move to the actuated position. Generally, the notch 70 can be referred
to as a bleed notch.
[0035] Turning to Figures 2 and 3, optionally, the second side 62 of the plate 58 can
define a groove 72 in fluid communication with the holes 56, and in certain embodiments in
fluid communication with the notch 70. Therefore, one or more holes 56 are in fluid
communication with the groove 72. Generally, the groove 72 is disposed between the holes
56 and the first surface 46 of the first seat 38 such that the holes 56 are spaced from the first
surface 46 of the first seat 38 when the plate 58 is in the rest position. Furthermore, the holes
56 are spaced from the first surface 46 of the first seat 38 when the plate 58 is in the actuated
position.
[0036] Referring to Figures 2-4, the plate 58 can also include a second seat 74
extending from the first side 60 facing away from the first seat 38. The valve assembly 12
can also include a biasing member 76 disposed in the first cavity portion 40 and engaging the
valve body 30 and the first side 60 of the plate 58. Generally, the second seat 74 surrounds
the biasing member 76 to position the biasing member 76 relative to the plate 58.
Furthermore, the second seat 74 surrounds the holes 56. The biasing member 76
continuously biases the cover device 54 to the rest position. In other words, the biasing
member 76 continuously biases the plate 58 into engagement with the first surface 46 of the
first seat 38, and more specifically, into engagement with the first surface 46 of the platform
50. Generally, the biasing member 76 and the cover device 54, and more specifically the
plate 58, cooperate to act as a head valve to limit vapors exiting the fuel tank during certain
conditions, such as for example, during refueling. When the vacuum is applied to the first
cavity portion 40, the vacuum acts on the large surface area of the diaphragm 64 which
moves the cover device 54 to the actuated position, and thus the cover device 54 bypasses the
head valve function. The biasing member 76 can be a coil spring, a dead weight, or any other
suitable configuration.
[0037] Generally, the first and second cavity portions 40, 42 have a substantially
equal first pressure when the cover device 54 is in the rest position. In other words, the first
and second cavity portions 40, 42 each have a pressure substantially equal to each other when
the cover device 54 is in the rest position. Said differently, the first and second cavity
portions 40, 42 each have a substantially equal pressure when the cover device 54 is in the
rest position. The first cavity portion 40 obtains a second pressure less than the first pressure
of the second cavity portion 42 when the vacuum is created in the first cavity portion 40
which moves the cover device 54 to the actuated position such that gaseous fluid flows from
the second cavity portion 42 through the first cavity portion 40 and out the outlet 36.
Therefore, the first cavity portion 40 obtains the second pressure less than the first pressure of
the second cavity portion 42 when the vacuum is created in the first cavity portion 40 which
moves the cover device 54 to the actuated position to increase fluid communication between
the first and second cavity portions 40, 42. Simply stated, when the gaseous fluid is removed
from the first cavity portion 40 of the valve body 30 to create the vacuum in the first cavity
portion 40, a pressure difference is obtained between the first and second cavity portions 40,
42. The vacuum created in the first cavity portion 40 quickly pops the cover device 54 to the
actuated position such that vapor flow is increased between the first and second cavity
portions 40, 42. Once the cover device 54 moves to the actuated position, vapors flow from
the second cavity portion 42 into the first cavity portion 40 and out the outlet 36 such that the
vacuum is created in the tank 14. The cover device 54 is designed to quickly open when the
vacuum is created to quickly create the vacuum in the tank 14 which minimize the sensor 22
falsely indicating that the vehicle is ready for maintenance. When the vacuum apparatus 18
is actuated to create the vacuum, vapors are pulled into the vacuum apparatus 18 from the
vapor control structure 16, the tank 14 and the fluid lines 2 1 between the tank 14 and the
vacuum apparatus 18. It is to be appreciated when the vacuum is created in the first cavity
portion 40, the pressure differential between the first and second cavity portions 40, 42 also
overcomes the force being applied to the plate 58 by the biasing member 76; therefore, the
cover device 54 also overcomes the force being applied by the biasing member 76 when
moving to the actuated position.
[0038] As shown in Figure 2, the valve assembly 12 can further include various
other components to minimize the liquid fluid, such as fuel, in the tank 14 from entering the
vapor control structure 16. For example, a float 78 can be disposed in the second cavity
portion 42 of the valve body 30. Generally, the float 78 is movable along the longitudinal
axis 34 between a first position and a second position relative to the valve body 30 in
response to a fluid level 80 (see Figure 1) inside the tank 14. The float 78 is shown in the
first position in Figure 2. In other words, when the float 78 is combined with a biasing force
from a second biasing member 82, the float 78 is buoyant in the fuel stored in the tank 14.
Thus, the float 78 can move along the longitudinal axis 34 depending on the fluid level 80 of
the fuel inside the tank 14. For example, if the fluid level 80 rises, the float 78 moves toward
the first seat 38. As another example, if the fluid level 80 descends, the float 78 moves away
from the first seat 38. It is to be appreciated that in a vehicle roll-over situation, the float 78
will move to the second position without the buoyancy of the float 78 affecting the float's
position due to the biasing force of the second biasing member 82 overcoming the buoyancy
of the float 78.
[0039] As another example, a sealing member 84 can be coupled to the float 78.
The sealing member 84 is spaced from the first seat 38 when the float 78 is in the first
position to increase fluid communication through the aperture 44. The sealing member 84
engages the first seat 38 when the float 78 is in the second position to minimize fluid
communication through the aperture 44. More specifically, in certain embodiments, the
sealing member 84 is spaced from the protrusion 52 when the float 78 is in the first position
and the sealing member 84 engages the protrusion 52 when the float 78 is in the second
position. Thus, if the vehicle is partially/fully rolled over, the float 78 can move to the
second position and the sealing member 84 engages the first seat 38 to seal the aperture 44,
which minimizes fuel from entering into the vapor control structure 16. Furthermore, if the
fluid level 80 is high in the tank 14 and the vehicle is on the grade, the fuel shifts in the tank
14 which can also cause the float 78 to move to the second position and the sealing member
84 into engagement with the first seat 38, which minimizes fuel from entering into the vapor
control structure 16. In addition, if the vehicle is being drove such that the fuel is sloshing
around in the tank 14, the sealing member 84 can engage the first seat 38 to seal the aperture
44 to minimize fuel from entering the vapor control structure 16. Liquid fluid or fuel could
affect or saturate the vapor control structure 16 if the liquid fluid or fuel reaches the vapor
control structure 16. Therefore, for example, the sealing member 84 selectively engages the
first seat 38 to seal the aperture 44 to prevent liquid fluid or fuel from entering the vapor
control structure 16.
[0040] Generally, when the vacuum is created, the float 78 is in the first position
and the sealing member 84 is spaced from the first seat 38 to allow vapors to flow through the
aperture 44. More specifically, the float 78 is in the first position when the vacuum apparatus
18 is actuated such that when the cover device 54 moves to the actuated position, vapors can
flow from the tank 14 through the aperture 44. In other words, the float 78 is in the first
position when the vacuum is created to move the cover device 54 to the actuated position
such that gaseous fluid flows from the second cavity portion 42 through the aperture 44 and
the hole 56, through the first cavity portion 40, and out the outlet 36.
[0041] In addition to the above, the configuration of the cover device 54 of Figures
2-4 can change. Generally, the cover device 54 of Figure 5 functions the same as discussed
above for Figures 2-4 and therefore the specific details will not be re-discussed for this
embodiment. In the embodiment of Figure 5, the plate 58 of the cover device 54 can be
modified to accommodate a head valve 86. For example, the head valve 86 can be disposed
in the first cavity portion 40. The head valve 86 can include a third seat 88 extending from
the plate 58 and opposing the first seat 38, with the third seat 88 extending outwardly from
the plate 58 away from the second cavity portion 42. Generally, the third seat 88 is spaced
from the holes 56 and spaced from the second seat 74. Furthermore, the plate 58 can define a
bore 90 along the longitudinal axis 34 between the holes 56. Therefore, the third seat 88
surrounds the bore 90 and the holes 56 are disposed between the third seat 88 and the second
seat 74. It is to be appreciated that the plate 58 and the third seat 88 can be integrally formed
to each other. In other words, the plate 58 and the third seat 88 can be formed of one piece.
[0042] The head valve 86 can also include a blocking member 92 movably disposed
in the third seat 88 such that the blocking member 92 selectively closes the bore 90.
Generally, the blocking member 92 rests in the third seat 88 to close the bore 90 while the
float 78 is in the first position. The blocking member 92 moves away from the third seat 88
to open the bore 90 when the tank 14 exceeds a predetermined pressure while the float 78 is
in the first position. When the blocking member 92 moves away from the third seat 88,
vapors can vent through the bore 90 into the vapor control structure 16. For example, the
blocking member 92 can move away from the third seat 88 to open the bore 90 during
operation of the vehicle when there is a large pressure differential between the tank 14 and
the second cavity portion 42. Generally, the blocking member 92 remains in engagement
with the plate 58 (blocking the bore 90) when the vacuum is created by the vacuum apparatus
18 and the cover device 54 moves to the actuated position. Furthermore, the blocking
member 92 generally remains in engagement with the plate 58 (blocking the bore 90) during
refueling of the vehicle which is a relatively low pressure event. It is to be appreciated that
the head valve 86 does not affect the function of the cover device 54. In certain
embodiments, the blocking member 92 can be a ball as shown in Figure 5. It is to be
appreciated that the blocking member 92 can be any suitable configuration. The head valve
86 can also be referred to as a pressure relief valve.
[0043] The notch 70 as discussed above for the embodiment of Figures 2-4 can be
relocated for the embodiment of Figure 5. For example, the notch 70 can be disposed
adjacent to the bore 90 (see Figure 5) instead of adjacent to the aperture 44 (see Figures 2-4).
The notch 70 provides fluid communication between the first and second cavity portions 40,
42 to substantially equalize small pressure differences between the first and second cavity
portions 40, 42 when the cover device 54 is in the rest position. In other words, the notch 70
allows a small amount of fluid communication between the first and second cavity portions
40, 42 when the blocking member 92 engages the bore 90 to substantially equalize small
pressure differentials. Therefore, these small pressure differences between the first and
second cavity portions 40, 42 are less than the pressure differences which cause the cover
device 54 to move to the actuated position.
[0044] Optionally, the cover device 54 can include a seal 94 (see Figure 5) coupled
to one of the first surface 46 of the first seat 38 and the second side 62 of the plate 58 for
minimizing fluid flowing or escaping between the first seat 38 and the plate 58 when the plate
58 is in the rest position. In one embodiment, the seal 94 is attached to the first surface 46 of
the first seat 38. In another embodiment, the seal 94 is attached to the second side 62 of the
plate 58. The seal 94 is generally disposed between the bore 90 and the holes 56. In other
words, the seal 94 surrounds the bore 90. It is to be appreciated that the seal 94 can be any
suitable configuration and location. Furthermore, the seal 94 can be utilized in the
embodiment of Figures 2-4. It is to also be appreciated that optionally, the groove 72 can be
eliminated in the cover device 54 as shown in Figure 5.
[0045] Turning to Figure 6, the present teachings also provide the method 1000 of
creating the vacuum in the tank 14 of the vehicle when performing the diagnostic test. The
method 1000 includes providing 1002 the valve body 30 adapted to be attached to the tank
14. The valve body 30 can be attached to the tank 14 as discussed above. The valve body 30
includes the first cavity portion 40 and the second cavity portion 42 separated by the first seat
38 as also discussed above.
[0046] The method 1000 also includes minimizing 1004 flow of gaseous fluid
between the hole 56 in the cover device 54 and the aperture 44 of the seat 38 when the cover
device 54 is in the rest position engaging the seat 38. The first and second cavity portions 40,
42 each have the substantially equal pressure when the cover device 54 is in the rest position.
It is to be appreciated that the gaseous fluid can be vapors as discussed above.
[0047] The method 1000 further includes removing 1006 gaseous fluid from the
first cavity portion 40 of the valve body 30 to create the vacuum in the first cavity portion 40
and the pressure difference between the first and second cavity portions 40, 42. In addition,
the method 1000 includes moving 1008 the cover device 54 to the actuated position spaced
from the seat 38 in response to the vacuum creating the pressure difference between the first
and second cavity portions 40, 42. Furthermore, the method 1000 includes increasing 1010
flow of the gaseous fluid between the hole 56 in the cover device 54 and the aperture 44 of
the seat 38 when the cover device 54 is in the actuated position to increase flow of the
gaseous fluid between the first and second cavity portions 40, 42 to create the vacuum in the
tank 14.
[0048] Furthermore, the method 1000 can include actuating 1012 the vacuum
apparatus 18 to create the vacuum in the tank 14. More specifically, actuating 1012 the
vacuum apparatus 18 can include signaling the vacuum apparatus 18, via the controller 20, to
actuate. Therefore, the vacuum apparatus 18 can pull the vapors through the system 10 (e.g.,
through the tank 14, the vapor control structure 16 and the fluid tubes 2 1 between the tank 14
and the vacuum apparatus 18, etc.) to the vacuum apparatus 18 to create the vacuum. The
method 1000 can further include signaling 1014 one or more of the on/off valves 24, via the
controller 20, to open or close when the vacuum is created. In one embodiment, the on/off
valves 24 are closed when the vacuum is created.
[0049] The method 1000 can include signaling 1016 the controller 20, via one or
more sensors 22, whether the desired amount of pressure for the desired amount of time has
been obtained in the system 10. If the desired amount of pressure for the desired amount of
time has been obtained, the flow of gaseous fluid from the tank 14 to the vacuum apparatus
18 is suitable and the vehicle passes the diagnostic test. If the desired amount of pressure for
the desired amount of time is not obtained, an undesirable amount of gaseous fluid is seeping
to atmosphere in the system 10 (e.g., seeping through one or more of the tank 14, the vapor
control structure 16 and the fluid tubes 2 1 between the tank 14 and the vacuum apparatus 18,
etc.), and therefore, the controller 20 activates the indicator in the vehicle, or the indicator of
the stand-along device, to indicate that the vehicle did not pass the diagnostic test and the
system 10 is ready for maintenance.
[0050] It is to be appreciated that the order or sequence of performing the method
1000 as identified in the flowchart of Figure 6 is for illustrative purposes and other orders or
sequences are within the scope of the present teachings. It is to also be appreciated that the
method 1000 can include other features not specifically identified in the flowcharts of Figure
6.
[0051] Various other parameters can be included to perform the diagnostic test. For
example, when performing the diagnostic test, the vehicle has remained off for, at least, from
about 4 hours to about 8 hours to allow the engine temperature to be about the same or
identical to the air temperature outside. As another example, when performing the diagnostic
test, the tank 14 is from about 15 percent to about 85 percent full of fuel. Generally, two
diagnostic tests are performed in sequence to determine whether the system 10 is ready for
maintenance.
[0052] The reference numbers used in the drawings and the specification and the
corresponding components are as follows:
10 fluid detection system
12 valve assembly
14 tank
16 vapor control structure
18 vacuum apparatus
20 controller
2 1 fluid tubes
22 sensors
24 on/off valves
26 microprocessor
28 memory
30 valve body
32 cavity
34 longitudinal axis
36 outlet
38 first seat
40 first cavity portion
42 second cavity portion
44 aperture
46 first surface
48 second surface
50 platform
52 protrusion
54 cover device
56 hole
58 plate
60 first side
62 second side
64 diaphragm
66 outer edge
68 inner edge
70 notch
72 groove
74 second seat
76 biasing member
78 float
80 fluid level
82 second biasing member
84 sealing member
86 head valve
88 third seat
90 bore
92 blocking member
94 seal
1000 method
1002 providing
1004 minimizing
1006 removing
1008 moving
1010 increasing
1012 actuating
1014 signaling
1016 signaling
[0053] While the best modes for carrying out the many aspects of the present
teachings have been described in detail, those familiar with the art to which these teachings
relate will recognize various alternative aspects for practicing the present teachings that are
within the scope of the appended claims.
CLAIMS
1. A valve assembly (12) for a tank (14) of a vehicle, the assembly (12)
comprising:
a valve body (30) adapted to be attached to the tank (14), with the valve body (30)
defining a cavity (32) along a longitudinal axis (34) and defining an outlet (36) in fluid
communication with the cavity (32) for venting the tank (14);
a seat (38) disposed in the cavity (32) of the valve body (30) and separating the cavity
(32) into a first cavity portion (40) and a second cavity portion (42), with the seat (38)
defining an aperture (44) along the longitudinal axis (34) to provide fluid communication
between the first and second cavity portions (40, 42); and
a cover device (54) disposed between the seat (38) and the outlet (36), with the cover
device (54) defining at least one hole (56) therethrough, and with the cover device (54)
movable between a rest position engaging the seat (38) to minimize fluid communication
between the aperture (44) and the hole (56) and an actuated position spaced from the seat (38)
to increase fluid communication between the aperture (44) and the hole (56) when a vacuum
is created in the first cavity portion (40).
2. An assembly (12) as set forth in claim 1 wherein the cover device (54)
includes a plate (58) movable between the rest and actuated positions to selectively engage
the seat (38), with the plate (58) defining the at least one hole (56).
3. An assembly (12) as set forth in claim 2 wherein the cover device (54)
includes a diaphragm (64) attached to the plate (58) and the valve body (30) such that the
plate (58) and the diaphragm (64) cooperate to cover the seat (38), with the diaphragm (64) at
least partially movable with the plate (58) between the rest and actuated positions.
4. An assembly (12) as set forth in claim 2 wherein the at least one hole (56) is
further defined as a plurality of holes (56) spaced from each other, with the plate (58)
defining the holes (56).
5. An assembly (12) as set forth in claim 3 wherein the seat (38) includes a first
surface (46) facing the first cavity portion (40) and a second surface (48) facing the second
cavity portion (42), with the plate (58) selectively engaging the first surface (46) of the seat
(38), and with the diaphragm (64) spaced from the first surface (46) when the plate (58) is in
the rest and actuated positions.
6. An assembly (12) as set forth in claim 5 wherein the first surface (46) of the
seat (38) defines a notch (70) adjacent to the aperture (44) to provide fluid communication
between the first and second cavity portions (40, 42) to substantially equalize small pressure
differences between the first and second cavity portions (40, 42) when the cover device (54)
is in the rest position.
7. An assembly (12) as set forth in claim 6 wherein the at least one hole (56) is
further defined as a plurality of holes (56) spaced from each other and wherein the plate (58)
includes a first side (60) and a second side (62) opposing each other, with the first and second
sides (60, 62) of the plate (58) defining the holes (56) therethrough, and wherein the second
side (62) of the plate (58) defines a groove (72) in fluid communication with the holes (56)
and the notch (70), with the groove (72) disposed between the holes (56) and the first surface
(46) of the seat (38) such that the holes (56) are spaced from the first surface (46) of the seat
(38) when the plate (58) is in the rest position.
8. An assembly (12) as set forth in claim 1wherein the plate (58) includes a first
side (60) and a second side (62) opposing each other and wherein the seat (38) is further
defined as a first seat (38) and the plate (58) includes a second seat (74) extending from the
first side (60) facing away from the first seat (38), and further including a biasing member
(76) disposed in the first cavity portion (40) and engaging the valve body (30) and the first
side (60) of the plate (58), with the second seat (74) surrounding the biasing member (76) to
position the biasing member (76) relative to the plate (58).
9. An assembly (12) as set forth in claim 1wherein the first and second cavity
portions (40, 42) have a substantially equal first pressure when the cover device (54) is in the
rest position, and the first cavity portion (40) obtains a second pressure less than the first
pressure of the second cavity portion (42) when the vacuum is created in the first cavity
portion (40) which moves the cover device (54) to the actuated position such that fluid flows
from the second cavity portion (42) through the first cavity portion (40) and out the outlet
(36).
10. An assembly (12) as set forth in claim 1 further including a float (78) disposed
in the second cavity portion (42) of the valve body (30), with the float (78) movable along the
longitudinal axis (34) between a first position and a second position relative to the valve body
(30) in response to a fluid level (80) inside the tank (14), and further including a sealing
member (84) coupled to the float (78), with the sealing member (84) spaced from the seat
(38) when the float (78) is in the first position and the sealing member (84) engages the seat
(38) when the float (78) is in the second position, and with the float (78) being in the first
position when the vacuum is created to move the cover device (54) to the actuated position
such that fluid flows from the second cavity portion (42) through the aperture (44) and the
hole (56), through the first cavity portion (40), and out the outlet (36).
11. A valve assembly (12) for a tank (14) of a vehicle, the assembly (12)
comprising:
a valve body (30) adapted to be attached to the tank (14), with the valve body (30)
defining a cavity (32) along a longitudinal axis (34) and defining an outlet (36) in fluid
communication with the cavity (32) for venting the tank (14);
a seat (38) disposed in the cavity (32) of the valve body (30) and separating the cavity
(32) into a first cavity portion (40) and a second cavity portion (42), with the seat (38)
including a platform (50) defining an aperture (44) along the longitudinal axis (34) to provide
fluid communication between the first and second cavity portions (40, 42); and
a cover device (54) disposed between the seat (38) and the outlet (36), with the cover
device (54) defining at least one hole (56) therethrough, and with the cover device (54)
movable between a rest position engaging the platform (50) to minimize fluid communication
between the aperture (44) and the hole (56) and an actuated position spaced from the platform
(50) to increase fluid communication between the aperture (44) and the hole (56) when a
vacuum is created in the first cavity portion (40);
wherein the first and second cavity portions (40, 42) have a substantially equal first
pressure when the cover device (54) is in the rest position, and the first cavity portion (40)
obtains a second pressure less than the first pressure of the second cavity portion (42) when
the vacuum is created in the first cavity portion (40) which moves the cover device (54) to the
actuated position to increase fluid communication between the first and second cavity
portions (40, 42).
12. An assembly (12) as set forth in claim 11 wherein the cover device (54)
includes a plate (58) movable between the rest and actuated positions to selectively engage
the platform (50), with the plate (58) defining the at least one hole (56), and wherein the
cover device (54) includes a diaphragm (64) attached to the plate (58) and the valve body
(30) such that the plate (58) and the diaphragm (64) cooperate to cover the platform (50),
with the diaphragm (64) at least partially movable with the plate (58) between the rest and
actuated positions.
13. An assembly (12) as set forth in claim 12 wherein the platform (50) including
a first surface (46) facing the first cavity portion (40) and a second surface (48) facing the
second cavity portion (42), with the plate (58) selectively engaging the first surface (46) of
the platform (50), with the diaphragm (64) being spaced from the first surface (46) when the
plate (58) is in the rest and actuated positions.
14. An assembly (12) as set forth in claim 11wherein the seat (38) includes a
protrusion (52) extending from the platform (50) into the second cavity portion (42), with the
protrusion (52) further defining the aperture (44), and further including a float (78) disposed
in the second cavity portion (42) of the valve body (30), with the float (78) movable along the
longitudinal axis (34) between a first position and a second position relative to the valve body
(30) in response to a fluid level (80) inside the tank (14), and further including a sealing
member (84) coupled to the float (78), with the sealing member (84) spaced from the
protrusion (52) when the float (78) is in the first position and the sealing member (84)
engages the protrusion (52) when the float (78) is in the second position, and with the float
(78) being in the first position when the vacuum is created to move the cover device (54) to
the actuated position such that fluid flows from the second cavity portion (42) through the
aperture (44) and the hole (56), through the first cavity portion (40), and out the outlet (36).
15. A method (1000) of creating a vacuum in a tank (14) of a vehicle when
performing a diagnostic test, the method (1000) comprising:
providing a valve body (30) adapted to be attached to the tank (14), with the valve
body (30) including a first cavity portion (40) and a second cavity portion (42) separated by a
seat (38);
minimizing flow of gaseous fluid between a hole (56) in a cover device (54) and an
aperture (44) of the seat (38) when the cover device (54) is in the rest position engaging the
seat (38), with the first and second cavity portions (40, 42) each having a substantially equal
pressure when the cover device (54) is in the rest position;
removing gaseous fluid from the first cavity portion (40) of the valve body (30) to
create a vacuum in the first cavity portion (40) and a pressure difference between the first and
second cavity portions (40, 42);
moving the cover device (54) to an actuated position spaced from the seat (38) in
response to the vacuum creating the pressure difference between the first and second cavity
portions (40, 42); and
increasing flow of the gaseous fluid between the hole (56) in the cover device (54)
and the aperture (44) of the seat (38) when the cover device (54) is in the actuated position to
increase flow of the gaseous fluid between the first and second cavity portions (40, 42) to
create the vacuum in the tank (14).