U.S. patent application number 09/755478 was filed with the patent office on 2001-08-09 for vent valve and fuel pump module.
This patent application is currently assigned to Walbro Corporation. Invention is credited to Crary, Lynwood F., Johansen, Mark R..
Application Number | 20010011538 09/755478 |
Document ID | / |
Family ID | 25039318 |
Filed Date | 2001-08-09 |
United States Patent
Application |
20010011538 |
Kind Code |
A1 |
Crary, Lynwood F. ; et
al. |
August 9, 2001 |
Vent valve and fuel pump module
Abstract
A high flow rate, two stage fuel vapor vent valve assembly
utilizing two float valves that provide a progressive closing of a
vapor outlet to control the venting of fuel vapors from a fuel tank
and the addition of liquid fuel to the tank. A first float closes a
portion of the vapor outlet in response to liquid fuel at a first
level relative to the valve. A second float closes the remainder of
the vapor outlet in response to liquid fuel at a second level
higher than the first level. One or more separate baffles are
constructed and arranged to prevent the escape of liquid fuel
through the vapor outlet.
Inventors: |
Crary, Lynwood F.; (Preston,
CT) ; Johansen, Mark R.; (Wallingford, CT) |
Correspondence
Address: |
Matthew J. Schmidt
Reising, Ethington, Barnes, Kisselle,
Learman & McCulloch, P.C.
P.O. Box 4390
Troy
MI
48099-4390
US
|
Assignee: |
Walbro Corporation
|
Family ID: |
25039318 |
Appl. No.: |
09/755478 |
Filed: |
January 5, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09755478 |
Jan 5, 2001 |
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09300929 |
Apr 28, 1999 |
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6213100 |
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Current U.S.
Class: |
123/509 ;
137/202 |
Current CPC
Class: |
B29C 65/08 20130101;
B29C 66/532 20130101; F16K 24/042 20130101; B60K 2015/0344
20130101; B29L 2031/7172 20130101; B29C 66/71 20130101; B29L
2031/7496 20130101; Y10T 137/0874 20150401; B29C 66/1222 20130101;
F02M 37/20 20130101; B60K 15/03519 20130101; F02M 37/103 20130101;
Y10T 137/3099 20150401; B29K 2059/00 20130101; B29C 66/1224
20130101; B60K 15/035 20130101; B29C 66/131 20130101; B29C 66/71
20130101; B29K 2059/00 20130101 |
Class at
Publication: |
123/509 ;
137/202 |
International
Class: |
F02M 025/08; F16T
001/20 |
Claims
What is claimed is:
1. A vapor vent valve for a fuel tank, comprising: a vapor outlet
communicating an interior of the fuel tank with an exterior of the
fuel tank and through which fuel vapor may flow out of the fuel
tank; a fill cup having an opening at one end and a sidewall
extending to the open end; a shell defining an interior space,
disposed in part in the fill cup and having a sidewall with an
opening therethrough and an upper edge. a flow passage defined
between the fill cup sidewall and the shell sidewall communicating
with the opening of the fill cup and the opening through the
sidewall to permit fluid which flows into the opening of the fill
cup to enter the interior space through the opening in the sidewall
of the shell; a first float having an opening aligned with the
vapor outlet, slidably received in the interior space and
responsive to the level of liquid fuel in the interior space to
partially close the vapor outlet at or above a certain first level
of fuel in the fuel tank and permit fluid flow through the vapor
outlet only through the opening in the first float; a second float
slidably received in the interior space, responsive to the level of
liquid fuel in the interior space to close the opening in the first
float when acted on by liquid fuel at or above a second level of
fuel in the fuel tank to prevent fluid flow through the opening in
the first float; a baffle surrounding an upper portion of the shell
including the upper edge of the shell; and a vapor flow path
communicating with the interior of the fuel tank at a location
above the second level and having an inlet defined at least in part
between the baffle and the shell disposed under the upper edge of
the shell, and having a portion defined above the upper edge of the
shell with the vapor outlet and shell arranged so that in order for
fluid in the fuel tank to reach the vapor outlet through the vapor
flow path, the fluid must travel upwardly between the baffle and
shell, laterally over the edge of the shell, further laterally to
the vapor outlet and upwardly to flow through the vapor outlet,
permitting fuel vapor to exit the fuel tank while preventing liquid
fuel flow through the vapor outlet.
2. The valve of claim 1 which also comprises a bottom wall of the
shell defining in part the interior space and a check valve which
prevents liquid fuel flow from the fuel tank into the interior
space through the opening in the bottom wall of the shell and
permits liquid fuel flow from the interior space to the fuel tank
under at least some fuel level conditions in the fuel tank.
3. The valve of claim 2 wherein the check valve comprises a disk
buoyant in liquid fuel which when immersed in liquid fuel is raised
into engagement with the bottom wall of the shell to close the
opening in the bottom wall.
4. The valve of claim 3 wherein the fill cup has a bottom wall with
an opening therethrough and the check valve is disposed between the
bottom wall of the fill cup and the bottom wall of the shell.
5. The valve of claim 1 wherein the first float has an inner
chamber and the second float is slidably carried in the inner
chamber of the first float.
6. The valve of claim 5 which also comprises a closure carried by
the first float, the closure having a passage therethrough defining
the opening through the first float, and the second float is
engageable with the closure to close the passage in response to
certain liquid fuel level conditions in the inner chamber.
7. The valve of claim 6 wherein the closure defines a valve seat
surrounding the passage and engageable by the second float.
8. The valve of claim 1 wherein the shell has an outwardly
extending flange which directs liquid fuel landing on the flange
away from the opening of the fill cup.
9. The valve of claim 8 wherein the flange extends radially
outwardly from the shell to a distance at least equal to the radial
distance between the baffle and shell so that any fuel flowing out
of the vapor flow path flows on the flange and is directed by the
flange back to the fuel tank.
10. The valve of claim 5 wherein the first float has an opening
communicating the interior space with the inner chamber.
11. The valve of claim 1 which also comprises a cap attached to the
shell and having an opening defining the vapor outlet.
12. The vapor of claim 11 wherein the cap has a depending skirt
defining the baffle.
13. The valve of claim 11 wherein the cap has mounting tabs
extending therefrom connectable to a wall of the fuel tank.
14. The valve of claim 1 wherein the shell is connectable with a
flange portion of a module carried by the fuel tank and the vapor
outlet is defined in the flange portion.
15. The valve of claim 1 wherein the opening in the sidewall of the
shell is at a height at or below the uppermost extent of the
sidewall of the fill cup.
16. The valve of claim 6 wherein the second float also comprises a
cage carried by the second float and engageable with the closure to
close the passage through the closure in response to certain liquid
fuel level conditions in the inner chamber.
17. The valve of claim 16 wherein the second float is movable
relative to the cage and the cage has a plurality of arms of
substantially the same length and fingers carried by the arms
engageable with the second float to limit relative movement between
the cage and second float.
18. A fuel pump module extending at least in part into a fuel tank,
comprising: a flange portion connectable to a wall of the fuel tank
and having a vapor outlet extending therethrough and an annular
depending skirt extending into the fuel tank when the flange
portion is mounted to the fuel tank; a reservoir portion carried by
the flange portion and disposed in the fuel tank when the flange
portion is mounted to the fuel tank; a vent valve carried by the
flange portion and having: a shell connectable to the flange
portion with an upper portion of the shell including an upper edge
of the shell within and adjacent to the skirt, said shell defining
an interior space and having a sidewall with an opening
therethrough; a fill cup having a sidewall and an open end, the
fill cup is received at least in part around the sidewall of the
shell; a flow passage defined between the fill cup sidewall and the
shell sidewall, and communicating the opening of the fill cup with
the opening through the sidewall to permit fluid which flows into
the opening of the fill cup to enter the interior space through the
opening in the sidewall of the shell; a first float having an
opening aligned with the vapor outlet, slidably received in the
interior space and responsive to the level of liquid fuel in the
interior space to partially close the vapor outlet at or above a
certain first level of fuel in the fuel tank and permit fluid flow
through the vapor outlet only through the opening in the first
float; and a second float slidably received in the interior space,
responsive to the level of liquid fuel in the interior space to
close the opening in the first float when acted on by liquid fuel
at or above a second level of fuel in the fuel tank to prevent
fluid flow through the opening in the first float, whereby fuel
which flows over the sidewall of the fill cup and into the opening
of the fill cup rapidly fills the interior space with liquid fuel
to the same height as the liquid fuel in the fuel tank so that the
float assembly is rapidly responsive to the fuel level in the fuel
tank when the fuel level in the fuel tank is above the sidewall of
the fill cup.
19. The valve of claim 18 wherein the first float has an inner
chamber and the second float is slidably carried in the inner
chamber of the first float.
20. The valve of claim 18 which also comprises a closure carried by
the first float, the closure having a passage therethrough defining
the opening through the first float, and the second float is
engageable with the closure to close the passage in response to
certain liquid fuel level conditions in the inner chamber.
21. The valve of claim 20 wherein the closure defines a valve seat
surrounding the passage and engageable by the second float.
22. The valve of claim 19 wherein the first float has an opening
communicating the interior space with the inner chamber.
23. The valve of claim 20 wherein the second float also comprises a
cage carried by the second float and engageable with the closure to
close the passage through the closure in response to certain liquid
fuel level conditions in the inner chamber.
24. The valve of claim 23 wherein the second float is movable
relative to the cage and the cage has a plurality of arms of
substantially the same length and fingers carried by the arms
engageable with the second float to limit relative movement between
the cage and second float.
25. A vapor vent valve for a fuel tank, comprising: a vapor outlet
through which fuel vapor may flow out of the fuel tank; a fill cup
having an open end and a continuous imperforate sidewall leading to
the open end; a shell disposed in part in the fill cup, defining at
least in part an interior space and having an opening therethrough
communicating with the open end of the fill cup, the opening being
shielded from splashing liquid fuel by the fill cup; a first float
having an opening aligned with the vapor outlet, slidably received
in the interior space and responsive to liquid fuel in the interior
space at least when said liquid fuel is at a level above the fill
cup sidewall to partially close the vapor outlet at or above a
certain first level of fuel in the fuel tank and permit fluid flow
through the vapor outlet only through the opening in the first
float; and a second float slidably received in the interior space,
responsive to a level of liquid fuel in the interior space above
that which causes the first float to partially close the vapor
outlet to close the opening in the first float when acted on by
liquid fuel at or above a second level of fuel in the fuel tank to
prevent fluid flow through the opening in the first float.
26. The valve of claim 25 wherein the first float has an inner
chamber and the second float is slidably carried in the inner
chamber of the first float.
27. The valve of claim 26 which also comprises a closure carried by
the first float, the closure having a passage therethrough defining
the opening through the first float, and the second float is
engageable with the closure to close the passage in response to
certain liquid fuel level conditions in the inner chamber.
28. The valve of claim 26 wherein the first float has an opening
communicating the interior space with the inner chamber.
29. The valve of claim 27 wherein the second float also comprises a
cage carried by the second float and engageable with the closure to
close the passage through the closure in response to certain liquid
fuel level conditions in the inner chamber.
30. The valve of claim 29 wherein the second float is movable
relative to the cage and the cage has a plurality of arms of
substantially the same length and fingers carried by the arms
engageable with the second float to limit relative movement between
the cage and second float.
Description
REFERENCE TO CO-PENDING APPLICATION
[0001] This patent application is a continuation-in-part of U.S.
patent application Ser. No. 09/300,929, filed on Apr. 28, 1999.
FIELD OF THE INVENTION
[0002] This invention relates generally to vehicle fuel systems and
more particularly to a vapor vent valve for a vehicle fuel tank and
a fuel pump module incorporating such a vapor vent valve.
BACKGROUND OF THE INVENTION
[0003] Environmental concerns and governmental regulations require
reduced emissions of volatile hydrocarbon fuel vapors into the
atmosphere. One source of hydrocarbon fuel vapors is fuel tanks of
vehicles using gasoline or other hydrocarbon fuels with high
volatility. Fuel vapor can escape to the atmosphere during the
filling of the tanks and usually, even after the tanks are filled.
The use of an onboard vapor recovery system to remove excess fuel
vapor from the fuel tank is one solution to the problem. Typically,
a canister with activated charcoal therein receives fuel vapors
through a valve assembly mounted in the top of the fuel tank and
communicates with the intake manifold of the vehicle engine for
withdrawing fuel vapor from the canister during operation of the
engine. The valve assembly may have a valve responsive to the level
of fuel in the tank that enables the valves to stay open at a
sufficiently low fuel level to permit fuel vapors to flow from the
fuel tank into the canister. As the fuel level rises during filling
to approach a desired maximum fuel level or quantity of fuel in the
tank, a float is raised to close the valve to prevent liquid fuel
from flowing through the valve and into the vapor canister. The
closed valve also prevents fuel vapor from flowing into the vapor
canister. One such system is disclosed in U.S. Pat. No. 5,
579,802.
[0004] Some of these systems require a high capacity or high flow
rate to control the flow of vapor from the fuel tank to the vapor
storage canister. Current high capacity or high flow rate valve
designs tend to be forced into and held in a closed position, when
they should be open, by the vapor pressure in the fuel tank. This
prevents vapor from flowing through the valve and into the vapor
storage canister defeating the purpose of the system. Further,
prior fuel level and vapor vent valves utilize a single float
responsive to the fuel level in the fuel tank to close the valve.
This single float arrangement maintains the valve closed while the
fuel level remains at or near the desired maximum level of fuel in
the tank to limit the amount of liquid fuel which undesirably
escapes through the valve. Maintaining the valve closed while the
fuel level remains at or near the maximum level of fuel in the tank
is undesirable because the addition of fuel to the tank when the
valve is closed will increase the pressure within the tank and
increase the discharge of hydrocarbon fuel vapors into the
atmosphere.
[0005] Further, when a vehicle stops, turns rapidly or is
travelling across rough terrain significant splashing or sloshing
of fuel in the fuel tank can occur. It has been found that the
splashing and sloshing of fuel in the tank is particularly bad when
the tank is between 1/4 and 3/4 full. Conventional vapor vent
valves permit an undesirable amount of liquid fuel to escape from
the fuel tank through the vent valve whereupon it flows to the fuel
vapor canister which has a limited volume and storage capacity and
is rapidly filled by liquid fuel. Typically, the liquid fuel
escapes from conventional vent valves because the outlet thereof is
not adequately protected from sloshing or splashing fuel and the
valve closure mechanism is not responsive enough to rapidly close
the valve and prevent such liquid fuel escape.
[0006] Typical vapor vent valves are mounted within an opening
through the vehicle fuel tank, and a fuel pump is mounted through a
separate opening in the fuel tank. Additional openings through the
fuel tank may be provided to mount additional components such as an
overpressure relief valve and the like. Each opening through the
fuel tank provides a leak path through which hazardous hydrocarbon
fuel vapors may escape to the atmosphere.
SUMMARY OF THE INVENTION
[0007] A high flow rate, two stage fuel vapor vent valve assembly
utilizing two float valves that provide a progressive closing of a
vapor outlet to control the venting of fuel vapors from a fuel tank
and the addition of liquid fuel to the tank. A first float closes a
portion of the vapor outlet in response to liquid fuel at a first
level relative to the valve. A second float closes the remainder of
the vapor outlet in response to liquid fuel at a second level
higher than the first level. One or more separate baffles are
constructed and arranged to prevent the escape of liquid fuel
through the vapor outlet.
[0008] Preferably, to reduce the number of openings in the fuel
tank and to simplify manufacture and assembly of the vapor vent
valve assembly, it can be formed at least in part as an integral
portion of a fuel pump module disposed within the fuel tank.
Ideally, an upper portion of the vent valve assembly defining the
vapor outlet can be formed as an integral portion of a flange of
the fuel pump module sealed to the fuel tank. This eliminates a
leak path around a body of the vent valve assembly defining the
vapor outlet to reduce the likelihood of liquid fuel escaping from
the fuel tank. Still further, providing the vapor vent valve
assembly integral with the fuel pump module prevents damage to the
vapor vent valve assembly should a lower portion of the fuel pump
module, containing the fuel pump, break away from the upper flange
sealed to the fuel tank during a vehicle accident.
[0009] Objects, features, and advantages of this invention include
providing a vapor vent valve assembly and fuel pump module which
has a high flow rate or capacity, opens and closes in response to
the level of fuel in the tank, prevents liquid fuel from escaping
from the fuel tank to the vapor receiving canister, closes in a
vehicle rollover condition, limits the maximum level of fuel within
the fuel tank during filling, enables multiple shut-offs of a fuel
filler nozzle during filling of the fuel tank, at least
substantially prevents sloshing or splashing liquid fuel from
escaping through the vapor outlet, and is rugged, durable,
reliable, of relatively simple design and economical manufacture
and assembly and has a long useful life in service.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] These and other objects, features and advantages of this
invention will be apparent from the following detailed description
of the preferred embodiments and best mode, appended claims and
accompanying drawings in which:
[0011] FIG. 1 is a perspective view of a vapor vent valve assembly
according to the invention and illustrating a lower portion of the
assembly;
[0012] FIG. 2 is a perspective view of the vapor vent valve
assembly of FIG. 1 illustrating an upper portion of the
assembly;
[0013] FIG. 3 is an exploded assembly view of the vapor vent valve
assembly;
[0014] FIG. 4 is a cross-sectional view of the vapor vent valve
assembly;
[0015] FIG. 5 is a perspective view of a fuel pump module which
carries a vapor vent valve assembly according to the invention;
[0016] FIG. 6 is a fragmentary sectional view of the fuel pump
module illustrating the vapor vent valve assembly;
[0017] FIG. 7 is a fragmentary sectional view of a vapor vent valve
assembly of a fourth embodiment of the invention; and
[0018] FIG. 8 is sectional view of a cage of the assembly of FIG.
7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] Referring in more detail to the drawings, FIG. 1 illustrates
a fuel vapor vent valve 10 constructed to be mounted on a fuel
tank, to communicate with the interior of the fuel tank and to
selectively permit fuel vapor to flow out of the fuel tank through
a vapor outlet 12 of the vent valve 10. The vapor vent valve 10 may
be a stand alone component which can be separately mounted on the
fuel tank or, as shown in FIGS. 5 and 6, may be incorporated as a
portion of a fuel pump module 14 mounted on the fuel tank. As shown
in FIGS. 3 and 4, the vent valve 10 has a first float 16 which
carries a closure 18 engageable with the vapor outlet 12 to
substantially close the outlet 12. The closure 18 has a passage 20
formed therethrough to permit a controlled flow of vapor through
the outlet 12 even when the closure 18 is engaged therewith. The
vapor vent valve 10 also has a second float 22 moveable relative to
the first float 16 and adapted to selectively close off fluid flow
through the passage 20 of the closure 18 to prevent fluid flow out
of the vapor outlet 12 of the valve 10.
[0020] Desirably, this two-stage shut off of the vapor outlet 12
also controls the filling of the fuel tank. When the closure 18
engages the vapor outlet 12, vapor flow out of the tank is
restricted and the pressure within the tank increases. This causes
fuel to back up within a fill pipe of the fuel tank, with liquid
fuel closing off a control port of a refueling nozzle of a fuel
station fuel dispensing pump to actuate an automatic shut-off
device in the nozzle in a known manner and prevent additional fuel
from being added to the tank. The closure 18 may move away from the
vapor outlet 12 and/or the fuel vapor in the tank may vent through
the passage 20 of the closure 18 to reduce the pressure in the
tank. Thus, additional fuel can be added to the tank even after the
first shut-off event. Subsequent shut-off events are caused by
reengagement of the closure with the vapor outlet 12 or the closing
off of the passage 20 of the closure 18 by the second float 22 at a
maximum fill level of the fuel tank. Desirably, this prevents
overfilling of the fuel tank and maintains a vapor dome in the
upper portion of the fuel tank and in communication with the vapor
vent valve 10. Usually, the closure 18 remains engaged with the
vapor outlet 12 and does not move away after the initial shut-off
event. Further venting and shut-off events are controlled through
passage 20.
[0021] The vapor outlet 12 of the vent valve 10 typically
communicates with a fuel vapor canister downstream of the vent
valve and the fuel tank. The canister is filled with activated
charcoal to absorb the hydrocarbon vapors received from the valve
assembly. The canister has an outlet through which fuel vapor is
discharged to an intake manifold of an engine for combustion of the
fuel vapors in the normal combustion cycle of the engine. The
canister may be mounted in various locations in the vehicle and is
connected to the vent valve 10 by a suitable flexible hose.
[0022] The vent valve 10 has a housing 30 defined in part by a
generally cylindrical and tubular shell 32 and an outer fill cup 34
surrounding a portion of the shell 32. The fill cup 34 has a
reduced diameter base 36 in which the shell 32 is closely received
preferably, as shown in FIG. 4, by a snap-fit of flexible fingers
35 on the fill cup 34 disposed into complementary slots 37 in the
shell 32. An enlarged diameter sidewall 38 extends from the base 36
to an open end 39 of the fill cup defining an annular gap 40
between the sidewall 38 and the shell 32. The sidewall 38 is open
at its upper end 39 to permit liquid fuel to flow over the sidewall
38 and into the gap 40. A plurality of radially inwardly and
axially extending ribs 42 may be formed in the sidewall 38 to
position the shell 32 therein. The fill cup 34 has a bottom wall 44
which spans the base 36 with through holes 46 permitting fluid flow
therethrough. The fill cup 34 and shell 32 are preferably formed of
a material resistant to degradation from exposure to hydrocarbon
fuels, and are preferably a polymeric material such as Acetal.
[0023] The shell 32 has a sidewall 48 in which a plurality of slots
50 are formed to permit liquid fuel to flow readily through the
shell 32. The slots 50 preferably extend at an axially height equal
to or below the height of the sidewall 38 of the fill cup 34 so
that the sidewall 38 shields or protects against splashing fuel
travelling upwardly relative to the vent valve 10 and through the
slots 50 to prevent such upwardly travelling fuel from escaping out
of the vent valve 10. A bottom wall 52 of the shell 32
substantially closes off its lower end with one or more through
holes 56 permitting fluid flow therethrough.
[0024] A radially outwardly extending and preferably
circumferentially continuous flange 58 is provided on the sidewall
48 above the slots 50 of the shell. The flange 58 extends
sufficiently radially outward to direct any liquid fuel which lands
on top of the flange 58 away from the fill cup 34 to return such
fuel to the fuel tank. To facilitate locating and connecting an
upper cap 60 to the shell 32, a plurality of radially outwardly
extending tabs 62 (FIG. 3) are provided at the upper end of the
shell 32 extending out of the cup 34. At least some of these tabs
62 have radially outwardly extending catches 64 constructed to
snap-fit into complimentary openings 66 in the cap 60. The
remaining tabs 62 provide additional separation between the cap 60
and sidewall 48 to provide flow paths between them through which
fuel vapor may flow into the valve 10.
[0025] Desirably, a check valve 70 controls the flow of fluid
through the holes 46, 56 of the bottom walls 44, 52 of the cup 34
and shell 32. The check valve 70 may be a generally flat disc 72
disposed between the bottom walls 44, 52 and retained and located
by a circular recess 74 formed in the bottom wall 52 of the shell
32. Desirably, the disc 72 is responsive when acted on by liquid
fuel to close the openings 56 in the bottom wall 52 of the shell 32
and prevent liquid fuel flow from the fuel tank through these
openings 56. When the disc 72 is not immersed in liquid fuel, any
fuel within the shell 32 may flow out of the valve 10 through the
openings 56, past the disc 72 and back into the fuel tank.
[0026] The cap 60 preferably has a plurality of radially outwardly
extending mounting tabs 76 with through holes 78 constructed to
receive pins (not shown) on the fuel tank which locate the vent
valve 10 relative to the fuel tank and which may be heat staked to
mount and seal the vent valve 10 to the fuel tank. The cap 60 has
an upper wall 82 with a throughbore 84 defining the vapor outlet 12
through which fuel vapor may escape from the fuel tank through the
vent valve 10. The vapor outlet 12 is defined in part by a nipple
86 extending from the upper wall 82 to receive a suitable conduit
communicating the vent valve 10 with a fuel vapor canister or the
like. Additionally, an annular depending valve seat 88 may be
provided surrounding the outlet 12. The cap 60 has a
circumferential depending skirt 90 extending from its upper wall 82
and surrounding an upper portion of the shell 32 in assembly. A
plurality of slots 66 are formed in the skirt 90 each adapted to
receive a catch 64 of a separate one of the tabs 62 on the shell 32
to connect and retain the cap 60 to the shell 32. The flange 58 on
the sidewall 48 of the shell 32 is preferably disposed adjacent to
the lower edge of the skirt 90 with the flange 58 extending
radially outwardly at least to the extent of an inner surface 94 of
the skirt 90 and desirably at least to and preferably farther
outwardly than an outer wall 96 of the skirt 90 to inhibit and
preferably prevent splashing or sloshing liquid fuel from flowing
between the skirt 90 and shell 32 and through the outlet 12 out of
the valve 10. The cap may also have finger-like shrouds 98
extending from the skirt in the area of the slots 66 to provide a
further shield from sloshing fuel.
[0027] To control the flow of fluid through the vent valve 10, a
float assembly 100 is slidably received in an interior space 101
defined between the shell 32 its bottom wall 52 and the cap 60. The
float assembly 100 comprises the first float 16 and second float 22
slidably received within the hollow first float 16. The first float
16 is preferably defined by a pair of inverted cup shaped bodies
106, 108 preferably interconnected by a snap-fit to define an inner
chamber 110 in which the second float 22 is received. The lower
body 106 may have a reduced diameter nose 112 adapted to be
received within the upper body 108 with a plurality of radially
outwardly extending catches 111 snap-fit in corresponding openings
113 in the upper body 108 to connect them together. To retain one
end of a spring 114 which yieldably biases the float assembly 100
toward its closed position, the lower body 106 preferably has an
annular recess 116 formed therein. The other end of the spring 114
is preferably disposed over and retained by the circular recess 74
in the bottom wall 52 of the shell 32. The upper body 108
preferably has one or more through holes or slots 118 formed
therein communicating the exterior of the float assembly 100 with
the chamber 110 in which the second float 22 is received to permit
fluid flow into the chamber 110. A through hole 120 is preferably
provided in a nose portion 122 of the upper body 108 with the
through hole 120 being generally aligned or coaxial with the vapor
outlet 12 of the cap 60. The closure 18 is press-fit within the
through hole 120 and is adapted to engage the valve seat 88 as
shown in FIG. 4, when the first float 16 is moved sufficiently away
from the bottom wall 52 of the shell 32. The passage 20 of the
closure communicates with the vapor outlet 12 the chamber 110 even
when the closure 18 is engaged with the valve seat 88. The closure
18 extends through the hole 120 and defines a second valve seat 123
in the chamber 110.
[0028] The second float 22 is slidably received within the chamber
110 and is preferably yieldably biased towards the closure 18 by a
spring 124. The second float 22 has an annular recess 126 which
retains one end of the spring 124 with the other end of the spring
124 retained on a circular projection 128 of the lower body 106 of
the first float 16. The second float 22 is buoyant in liquid fuel
such that when liquid fuel enters and rises in the chamber 110 the
second float 22 is raised upwardly into engagement with the valve
seat 123 of the closure 18 to seal off its passage 20. Desirably,
the weight of the second float 22 is chosen such that when liquid
fuel is no longer within the chamber 110 the weight of the second
float 22 is sufficient to remove it from the valve seat 123 and
reopen the passage 20 through the closure 18. The weight of the
second float 22 and the spring rate of the spring 124 biasing it
are also chosen such that if the vent valve 10 is turned over, such
as during a vehicle rollover accident, the second float 22 will be
urged into engagement with the valve seat 123 of the closure 18
even when immersed in liquid fuel to prevent liquid fuel from
flowing through the closure 18 and out of the vapor outlet 12.
Likewise, the weight of the entire float assembly 100 and the
spring rate of the spring 114 biasing it are chosen such that
during a vehicle roll-over accident the first float 16 will be
displaced to engage the closure 18 with the valve seat 88 of the
cap 60 to prevent liquid fuel from flowing out of the vapor outlet
therethrough. Desirably, to limit friction between the second float
22 and first float 16 the upper body 108 has a plurality of axially
elongate and radially inwardly extending ribs 130. Likewise, to
guide the first float 16 and reduce friction between it and the
inner wall of the shell 32, a plurality of axially elongate and
spaced apart ribs 132 are provided in the shell 32.
[0029] Accordingly, the vent valve 10 is comprised of a plurality
of relatively simple components which are preferably snap-fit
together for ease of assembly and manufacture. The vent valve 10 is
constructed and arranged to limit or prevent liquid fuel from
escaping from the fuel tank therethrough and is responsive to
provide a two stage shut-off of the vapor valve outlet 12.
Initially, when the closure 18 engages the valve seat 88 the
passage 20 through the closure 18 remains open, and when the second
float 22 is immersed in liquid fuel it is raised into engagement
with the valve seat 123 of the closure 18 to prevent fluid flow
through the closure 18, and hence, through the vapor outlet 12.
[0030] Operation
[0031] Absent liquid fuel acting on the float assembly 100, the
closure 18 is not engaged with the valve seat 88 of the cap 60 and
the second float 22 is likewise not engaged with the valve seat 123
of the closure 18 permitting fuel vapors within the fuel tank to
flow through the vapor passage between the skirt 90 and sidewall 48
and out of the vapor outlet 12. Fuel vapor may also flow through
the slots 50 in the shell 32 around the float assembly 100 and out
of the vapor outlet 12, or through the float assembly 100 and the
passage 20 through the closure 18 and out of the vapor outlet 12
for delivery to a fuel vapor canister or other vapor receiving
component.
[0032] As liquid fuel is added to the fuel tank such as by a filler
nozzle of a fuel station dispensing pump, the level of fuel in the
tank rises and eventually liquid fuel will engage the bottom of the
fill cup 34. As liquid fuel flows through the holes 46 in the
bottom wall 44 of the fill cup 34 the valve disc 72 is raised into
engagement with the bottom wall 52 of the shell 32 to close its
holes 56 and prevent liquid fuel from entering the interior space
101 of the vent valve 10 therethrough. The level of fuel in the
tank continues to rise as fuel is added therein until the level of
fuel reaches the open upper end 39 of the fill cup 34. When the
level of fuel is higher than the fill cup 34, fuel pours into the
fill cup 34 and through the slots 50 in the shell 32 rapidly
filling the interior space 101 of the vent valve 10 to the level of
fuel in the tank.
[0033] Desirably, as liquid fuel fills the interior space 101, air
is trapped within the lower body 106 of the first float 16
rendering the first float 16 and entire float assembly 100 buoyant
or merely increasing its buoyancy if it is buoyant in liquid fuel.
The rush of liquid fuel into the vent valve 10 and the air trapped
in the float assembly 100 quickly raises the float assembly 100
until the closure 18 engages the valve seat 88 closing off a major
portion of the vapor outlet 12. With the major portion of the vapor
outlet 12 closed, the pressure within the fuel tank rises rapidly
as fuel is added to the tank causing fuel to rise or back-up within
the fill pipe to engage the fuel fill nozzle and actuate its
automatic shut-off, temporarily stopping the addition of fuel to
the tank. Because the passage 20 through the closure 18 remains
open, fuel vapor may vent through the float assembly 100 and out of
the vapor outlet 12 through this passage 20 to reduce the pressure
within the fuel tank. Accordingly, when the pressure within the
fuel tank has decreased sufficiently, additional fuel may be added
to the fuel tank. The time required is dependent at least in part,
on the flow area of the passage 20. The larger the flow area, the
shorter the time needed to vent sufficient pressure from the tank,
and vice versa. A currently preferred passage 20 has a diameter of
about 0.10 of an inch.
[0034] Additional fuel added to the tank raises the level of fuel
in the tank further, with fuel in the vent valve 10 rising
correspondingly, until the fuel enters the chamber 110 containing
the second float 22. Eventually, the second float 22 will be raised
by liquid fuel within the chamber 110 until it engages with the
valve seat 123 of the closure 18 to prevent any fluid flow through
its passage 20. With the closure 18 engaged with the valve seat 88
and with the second float 22 engaged with the valve seat 123 of the
closure 18, the vapor outlet 12 is completely closed. Without any
exit for fuel vapor, the pressure within the fuel tank again
rapidly increases and the fuel automatic shut-off of the nozzle is
actuated by liquid fuel backing up into the fill pipe. Because the
second float 22 may have been raised into engagement with the valve
seat 123 of the closure 18 by splashing or sloshing fuel, it may
fall away from this valve seat 123 when the fuel settles in the
tank permitting additional fuel to be added to the fuel tank. When
the level of fuel is such that the second float 22 remains engaged
with the valve seat 123, no more fuel may be added to the fuel tank
because of the lack of venting of fuel vapor and the resulting
increased pressure in the fuel tank. The vapor outlet 12 remains
completely closed until the level of fuel in the tank is decreased
sufficiently to permit the second float 22 to fall away from the
valve seat 123 thereby opening the passage 20 of the closure 18 and
permitting fuel vapor to escape therethrough out of the fuel tank.
At some point the decreased fuel level will also permit the first
float 16 to fall away from the valve seat 88 due to the weight of
the float assembly 100 and the force of gravity acting on the
assembly. This removes the closure 18 from the valve seat 88 and
fully opens the vapor outlet 12 to permit a high flow rate of fuel
vapor to escape from the fuel tank.
[0035] Desirably, the vent valve 10 is constructed to at least
substantially inhibit and preferably prevent escape of liquid fuel
through the vapor outlet 12. Fuel splashing upwardly is prevented
from entering the slots 50 of the shell 32 by the fill cup 34 which
preferably extends at least as high as the slots 50. Further, the
annular flange 58 of the sidewall 48 of the shell 32 prevents
upwardly splashed or sloshing fuel from directly entering the vapor
flow path between the skirt 90 and shell 32. Still further, any
fuel which bypasses the flange 58 and enters the space between the
skirt 90 and shell 32 must travel laterally over the shell 32 and
further upwardly to escape out of the vapor outlet 12. This is
unlikely and due to the force of gravity acting on the fuel, any
fuel which enters the shell 32 will flow downwardly towards the
bottom of the shell 32 through the check valve 70 when the level of
fuel in the fuel tank permits. Still further, the depending skirt
90 of the cap 60 provides a shield or baffle which prevents liquid
fuel from laterally entering the shell 32 and escaping through the
vapor outlet 12.
[0036] To change the fuel level within the tank which causes the
first automatic shutoff of a fuel filler nozzle, the axial height
of the side wall 38 of the fill cup 34 can be changed. Notably, the
lower body 106 of the float assembly 100 is positioned at or below
the level of the top of the fill cup 34 such that when fuel flows
into the fill cup 34 the float assembly is raised relatively
rapidly to engage the closure 18 with the valve seat 88 and
initiate the first shut-off of the fuel filler nozzle. Accordingly,
regardless of the rate at which fuel is added to the fuel tank, the
height of the sidewall 38 of the fill cup 34 effectively controls
the fuel level at which the first automatic shut-off of a fuel
nozzle is obtained. Subsequent fuel fill levels which actuate
subsequent shut-offs of the fuel filler nozzle can be controlled by
the relative position and distance between the closure 18 and the
second float 22 of the float assembly 100 and their position within
the fuel tank because the buoyancy of the second float 22 (in
addition to at least the spring force acting on the second float 22
and the weight of the second float 22) controls the subsequent
automatic shut-offs of the fuel filler nozzle. Accordingly, a
plurality of automatic shut-offs may be provided with overfilling
of the tank being prevented by complete closure of the vapor outlet
12 to maintain a desirable vapor dome within the fuel tank.
[0037] Second Embodiment
[0038] As shown in FIGS. 5-6, a vapor vent valve 200 according to
the invention may be included as a portion of a fuel pump module 14
mounted on a top wall 204 of and extending into fuel tank 206. The
module 14 preferably has a flange portion 208 constructed to be
mounted on and sealed to the fuel tank 206 such as by ultrasonic
welding or other connection method, and a reservoir portion 210
connected to the flange portion 208 by one or more legs 212.
Desirably, the reservoir portion 210 is slidable on the legs 212
and is yieldably biased away from the flange portion 208 to ensure
that the bottom of the reservoir 210 is adjacent to a bottom wall
of the fuel tank 206.
[0039] The module 14 preferably contains a plurality of components
all received through a single opening in the fuel tank 206. For
example, the module may contain an electric motor fuel pump 214, a
fuel filter 216 downstream of the fuel pump outlet and upstream of
an outlet 218 of the module 14 through which fuel is delivered from
the fuel tank to an engine, a fuel pressure regulator 220 which may
communicate with fuel in the fuel filter 216 downstream of the fuel
pump 214, a fuel level sender (not shown) having a float responsive
to the level of liquid fuel in the fuel tank, electrical connectors
224 permitting wires to pass through from outside of the fuel tank
into the tank, such as to power the fuel pump 214 and communicate
with the fuel level sensor and other sensors, and one or more
sensors 222 which communicate conditions within the tank with a CPU
or other processing unit of a vehicle. The vapor vent valve 200 may
be carried by the flange portion 208 of the module 14 with a vapor
outlet 226 defined and molded in the flange 208 and an exterior
nipple 228 on the flange 208 suitable to receive a flexible hose
communicating the vapor outlet 226 with a fuel vapor canister.
[0040] As best shown in FIG. 6, the vapor vent valve 200, when
incorporated as a part of the fuel pump module 14, may have all of
the same components as the vent valve 10 except for the cap 60.
Desirably, the cap 60 can be replaced with structure integral with
the flange portion 208 of the fuel pump module 14. For instance,
the shell 32 may have outwardly extending catches 64 which
snap-fits into corresponding openings 230 in a depending skirt 232
of the flange portion 208. Additionally, the vapor outlet 226 and a
valve seat 234 surrounding the vapor outlet 226 may be integrally
formed in the flange portion 208. Desirably, the depending skirt
232 of the flange portion 208 is constructed and arranged in the
same manner as the skirt 90 of the cap 60 providing a relatively
circuitous vapor flow path 235 between the skirt 232 and the shell
32 requiring fuel vapor to flow between the skirt 232 and shell 32
and up over the upper end 237 of the shell 32 before reaching the
interior of the valve 10 and the vapor outlet 226. This at least
substantially inhibits and preferably prevents liquid fuel from
escaping through the vapor outlet 226. In all other respects, the
vent valve 200 may be constructed and arranged as disclosed with
regard to the first embodiment of the vent valve 10. Desirably,
including the vent valve 200 as a portion of the fuel pump module
14 eliminates the need for a separate opening through the fuel tank
206 to accommodate the vent valve 200. Further, to prevent leakage
of fuel from the fuel tank 206 during an accident, the legs 212
interconnecting the flange portion 208 and reservoir portion 210 of
the fuel pump module 202 may be frangible or constructed to break
during an accident to limit the maximum force on the flange portion
208 and the connection between the flange portion 208 and fuel
tank. With the vapor vent valve 200 within the fuel pump module 14,
the reservoir portion 210 and its contents, when they break away
from the flange portion during an accident, are not flung into the
vapor vent valve 200 and thereby eliminate the potential damage to
the vent valve 200 and leakage from the fuel tank which otherwise
may occur as a result thereof.
[0041] Third Embodiment
[0042] As an alternate embodiment, the vapor vent valve may be
provided with a closure 18 having a through passage 20 of very
small diameter, and preferably between about 0.020 and 0.040 of an
inch to provide a more restrictive flow of fluid therethrough when
the closure 18 is engaged with the vapor valve seat 88. Such an
arrangement can be used with the stand alone vent valve 10 or with
the vent valve 200 of the fuel pump module 14 without any other
modifications. Desirably, upon filling of the fuel tank, the first
shut-off of the fuel filler nozzle is obtained when the liquid fuel
flows over the fill cup 34 and raises the closure 18 of the float
assembly 100 into engagement with the valve seat 88 surrounding the
vapor outlet 12. Due to the small flow area of the passage 20
through the closure 18, while fuel vapor may vent from the fuel
tank, it does so at a relatively slow rate requiring a longer time
to reduce the pressure in the fuel tank. Accordingly, with the
relatively high pressure maintained in the fuel tank the fuel fill
nozzle even if actuated will not add additional fuel to the
tank.
[0043] Upon waiting a sufficient amount of time to permit a
sufficient amount of the fuel vapor to flow through the passage,
additional fuel may be added to the tank if desired, however, the
pressure in the tank will rapidly increase and thereby rapidly
cause a second shut-off of the fuel filler nozzle. Desirably, any
additional fuel shutoffs after the first shut-off are created by
the restricted flow rate of vapor through the passage 20 without
the second float 22 closing off the passage 20 as in the previous
embodiments. In any event, if sufficient fuel is added to the tank
the second float 22 will close off the passage 20 when it is
immersed in liquid fuel as in the previous embodiments.
Additionally, the inner float 102 will close off the passage in a
roll over accident situation as described with reference to the
first embodiment vent valve 10. Desirably, a number of fuel
shut-off events may occur before the second float 22 is immersed in
liquid fuel. Preferably, the fuel tank is not filled to the point
where the second float 22 is immersed in liquid fuel so that the
passage 20 through the closure 18 remains open and the fuel vapor
may vent from the fuel tank through this passage 20 even when the
tank is filled to the desired maximum fill level.
[0044] Accordingly, a fuel vapor vent valve 10, 200 of relatively
simple design is provided which at least substantially inhibits and
preferably prevents the escape of liquid fuel therethrough, permits
control of fuel shut-off events, permits control of a maximum fill
level in the fuel tank, prevents fuel leakage during a vehicle roll
over accident, is rapidly responsive and of relatively low cost to
manufacture. Desirably, the vent valve 10, 200 can be a stand alone
component separately mounted on the fuel tank or may be
incorporated into a fuel pump module 14 mounted on the fuel
tank.
[0045] Fourth Embodiment
[0046] A vapor vent valve 300 according to a fourth embodiment of
the invention, as shown in FIGS. 7 and 8, has a second float 302
carried in the first float 16 and having an upwardly projecting
stem with an enlarged head 306 at one end and a cage 308 carried on
the stem 304 for engaging the closure 18 and closing the vapor flow
passage 20. The cage 308 preferably has an upper wall 310 and a
plurality of circumferentially spaced arms 312 depending from the
upper wall 310 and leading to radially inwardly extending fingers
314. The arms 312 have a length which permits axial movement of the
cage 308 relative to the head 306 and the radially inwardly
extending fingers 314 engage the head 306 to limit movement of the
cage 308. The relative movement between the second float 302 and
cage 308 provides for increased force tending to unseat the cage
308 from the closure 18 to prevent corking or sticking of the cage.
Desirably, the length of each arm 312 is the same so that the head
306 engages the finger 314 on each arm 312 at essentially the same
time to provide a generally uniform force on all arms 312 tending
to unseat the cage 308 from the closure 18. In all other respects,
the vapor vent valve 300 according to the fourth embodiment may be
constructed in the same manner as the first embodiment or second
embodiment vent valves 10, 200.
* * * * *