LIQUID TRAP FOR FUEL VAPOR VALVE
TECHNICAL FIELD
[0001] The present invention relates to liquid traps, and more particularly to a liquid
trap and baffle that can be inserted into a fuel vapor valve.
BACKGROUND OF THE INVENTION
[0002] Fuel vapor valves, such as fuel limit vent valves (FLVVs), grade vent valves
(GVVs), and rollover valves (ROVs) are used in vehicle fuel emissions systems to control
vapor pressure, induce filler nozzle shutoff, and prevent fuel spillage from the system.
Although these valves are designed to minimize leakage of liquid fuel out of the valve, some
customers have increased the stringency of their requirements and have requested valves with
virtually zero leakage.
[0003] While it is possible to redesign the valves to meet these requirements, there is
a desire for a simpler solution that can reduce leaks in fuel vapor valves without requiring
extensive modifications to existing valves. There is also a desire for a leak-reduction device
that can also be incorporated into existing fuel vapor valves to reduce development time and
cost.
SUMMARY OF THE INVENTION
[0004] An insert for a fuel vapor valve traps liquid fuel and prevent the fuel from
leaking out of the valve. The insert includes a tube and a skirt disposed around the tube. The
skirt seals against a portion of the fuel vapor valve, such as against an inner wall of a valve
port or on a top portion of the valve to act as a valve cap. The tube and the skirt cooperate
with the fuel vapor valve to form a reservoir that traps liquid fuel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Figure 1 is a cross-sectional view of a liquid trap apparatus installed into a fuel
vapor valve;
[0006] Figure 2 is a cross-sectional view of a variation of the apparatus in Figure 1
installed into a fuel vapor valve; and
[0007] Figure 3 is a cross-sectional view of a liquid trap apparatus according to
another embodiment of the invention and installed into a fuel vapor valve.
DETAILED DESCRIPTION OF THE INVENTION
[0008] Referring to Figures 1 and 2, an insert 10 for a fuel vapor valve 11 (which is
only partially shown in the Figures) acts as trap for liquid fuel that may leak past a valve seal
12 and a valve seat 13. The position of the valve seal 12 may be controlled by, for example,
a float or any other known method or structure. Although the valve seal 12 and valve seat 13
may be designed to prevent leakage, fuel may still potentially leak past the valve seat 13 into
other portions of the valve 11 if the valve 11 is in certain orientations or inverted. The insert
10 is designed to act as a backup leak prevention structure to make the overall valve 11
virtually leakproof.
[0009] The insert 10 in the present embodiment includes a tube 14 and a skirt 16
surrounding the tube 14. The skirt 16 may be tube-shaped (Figures 1 and 2) or planar. The
skirt 16 also may be concentric with the tube 14. The tube 14 and skirt 16 form a reservoir
18 between the tube 14 and an inner wall of a port 20 in the valve 11. The reservoir 18 traps
liquid fuel that has escaped past the valve seat 13 from further leaking through the port 20
and out of the valve 11.
[0010] The insert 10 may be made from any material, such as plastic or metal, that is
appropriate for the valve in which the insert 10 will be used.
[0011] The skirt 16 may be sized so that it fits snugly within the port 20. The insert
10 can be secured inside the port 20 via any means that provides a seal between the skirt 16
and the inner wall of the port 20, including but not limited to press-fitting, welding, bonding,
and/or adhesives. The seal between the skirt 16 of the insert 10 and the port 20 prevents
liquid fuel that leaked past the valve seat 13 from leaking out of the valve 11 through the port
20.
[0012] The dimensions of the tube 14 and the skirt 16 may be selected to trap a
predetermined amount of liquid between the insert 10 and the port 20. For example, as
shown in Figure 1 and 2, the difference between the diameters of the tube 14 and the skirt 16,
as well as the length of the tube 14 itself, will change the volume of liquid trapped by the
insert 10. Figure 1, for example, shows an embodiment with a small difference between the
tube 14 and skirt 16 diameters and a relatively long tube 14, while Figure 2 shows an
embodiment with a large difference between the tube 14 and skirt 16 diameters and a shorter
tube 14. Varying the relative diameters of the tube 14 and skirt 16 as well as the tube 14
length will vary the liquid volume trapped by the insert 10.
[0013] Figure 3 illustrates the insert 10 according to another embodiment of the
invention. The insert 10 in this embodiment attached to a top portion 22 of the valve 11
instead of in the port 20. More particularly, the insert 10 may act as a liquid discriminating
cap that replaces an existing cap for the valve 11. The skirt 16 in this embodiment may be
shaped as a flange instead of a tube as in the embodiment of Figures 1 and 2 so that it can fit
be welded or otherwise attached to the top of the valve 11. The insert 10 in this embodiment
also includes an insert port 24 that is integrally formed as part of the insert 10, thereby
combining the functions of the insert 10 with the functions of a valve cap.
[0014] In this embodiment, the tube 10 and the skirt 14 of the insert 10 cooperate with
the top portion 22 of the valve 11 to create the reservoir 18 that traps liquid fuel leaking past
the valve seat 13. As in the embodiments of Figures 1 and 2, the length and diameter of the
tube 14 in this embodiment can be adjusted to change the volume of the reservoir 18. Since
the insert 10 of Figure 3 incorporates the port 24 into the insert 10 itself, this embodiment
may be used in valve designs having ports that are too small to accommodate the insert 10
shown in Figures 1 and 2.
[0015] The insert 10 according to any of the embodiments may also have functions
other than preventing leaks. For example, the insert 10 may also act as a baffle to restrict
sloshing of liquid fuel within the port 20. More particularly, the tube 14 breaks up fluid flow
in the port 20 to prevent sloshing. Also, the diameter of the tube 14 may be selected to act as
a metering orifice that restricts flow in a larger orifice. This would allow the same valve 11
design to be used for both high flow applications (without the insert 10) and low flow
applications (with the insert 10).
[0016] As a result, the insert 10 traps liquid fuel that may have leaked past the valve
seat 13 in the vapor valve 11, thereby making the valve 11 itself virtually leak-proof. The
simple structure of the insert 10 allows it to be retrofitted into existing valves 12. Since the
insert 10 does not require any changes in the valve 11 structure itself, and because the insert
10 has a simple deign, it is easy to create different inserts 10 that can be retrofitted to
different existing fuel vapor valves 11 and provide the desired leak-prevention characteristics
with minimal development time and cost.
[0017] While the best modes for carrying out the invention have been described in
detail, those familiar with the art to which this invention relates will recognize various
alternative designs and embodiments for practicing the invention within the scope of the
appended claims.
WHAT IS CLAIMED IS:
1. An insert for a fuel vapor valve, comprising:
a tube; and
a skirt disposed around the tube, wherein the skirt seals against a portion of the
fuel vapor valve,
and wherein the tube and the skirt cooperate with the portion of the fuel vapor
valve to form a reservoir that traps liquid fuel.
2. The insert of claim 1, wherein the portion of the fuel vapor valve is a port, and
wherein the skirt seals against an inner wall of the port.
3. The insert of claim 1, wherein the skirt is tube-shaped.
4. The insert of claim 1, wherein the skirt is planar.
5. The insert of claim 1, wherein the portion of the fuel vapor valve is a top
portion, and wherein the insert is attached to the top portion to act as a valve cap.
6. The insert of claim 5, further comprising an insert port that is integrally
formed as part of the insert.
7. The insert of claim 1, wherein a diameter of the tube, a length of the tube, and
a diameter of the skirt are selected to create a reservoir with a predetermined volume.
8. A fuel vapor valve, comprising:
a housing;
a valve seat formed in the housing;
a valve seal that can seal against the valve seat; and
an insert to trap liquid fuel that leaks past the valve seal, the insert having
a tube, and
a skirt disposed around the tube, wherein the skirt seals against a portion of the
fuel vapor valve,
and wherein the tube and the skirt cooperate with the portion of the fuel vapor valve
to form a reservoir that traps liquid fuel.
9. The fuel vapor valve of claim 8, wherein the skirt seals against an inner wall
of the port.
10. The fuel vapor valve of claim 8, wherein the insert is attached to the top
portion to act as a valve cap.
11. The fuel vapor valve of claim 10, further comprising an insert port that is
integrally formed as part of the insert.
12. The fuel vapor valve of claim 10, wherein a diameter of the tube, a length of
the tube, and a diameter of the skirt are selected to create a reservoir with a predetermined
volume.