U.S. patent application number 10/706158 was filed with the patent office on 2005-05-12 for fuel vent assembly with floatless rollover protection.
Invention is credited to Taxon, Morse N..
Application Number | 20050098160 10/706158 |
Document ID | / |
Family ID | 34552472 |
Filed Date | 2005-05-12 |
United States Patent
Application |
20050098160 |
Kind Code |
A1 |
Taxon, Morse N. |
May 12, 2005 |
FUEL VENT ASSEMBLY WITH FLOATLESS ROLLOVER PROTECTION
Abstract
A valve for use between a vehicle fuel tank vent and a vapor
recovery canister in a vehicle fuel tank containing liquid fuel,
such a valve comprises: a housing having a fuel tank side and a
vapor recovery canister side; and a vapor permeable membrane fixed
to the housing to block the passage of liquid fuel.
Inventors: |
Taxon, Morse N.; (Oak Park,
MI) |
Correspondence
Address: |
DAIMLERCHRYSLER INTELLECTUAL CAPITAL CORPORATION
CIMS 483-02-19
800 CHRYSLER DR EAST
AUBURN HILLS
MI
48326-2757
US
|
Family ID: |
34552472 |
Appl. No.: |
10/706158 |
Filed: |
November 12, 2003 |
Current U.S.
Class: |
123/516 |
Current CPC
Class: |
B60K 2015/03276
20130101; F02M 25/0836 20130101; B60K 15/03519 20130101 |
Class at
Publication: |
123/516 |
International
Class: |
F02M 025/08 |
Claims
1-3. (canceled)
4. The valve of claim 14, where said cone shaped vapor permeable
membrane has a narrow portion and a wide portion.
5. The valve of claim 4, where said cone shaped vapor permeable
membrane is positioned inside said housing with said narrow portion
oriented toward said fuel tank side.
6. The valve of claim 13, where said vapor permeable membrane is
cone shaped.
7. (canceled)
8. The valve of claim, 15 where said vapor permeable membrane is
pleated.
9. The valve of claim 13, where said vapor permeable membrane is a
double layer material.
10. The valve of claim 13, where said vapor permeable membrane is
an acrylic copolymer material on a polyamide support.
11. The valve of claim 13, where said vapor permeable membrane has
pore sizes of 0.2 to 5.0 microns.
12. The valve of claim 13, where said vapor permeable membrane has
pore sizes of 0.45 to 0.80 microns.
13. A valve for use between a vehicle fuel tank vent and a vapor
recovery canister in a vehicle fuel tank containing liquid fuel,
said valve comprising: a housing having a fuel tank side and a
vapor recovery canister side; and a pleated, vapor permeable
membrane fixed to said vapor recovery canister side to block
passage of liquid fuel.
14. A valve for use between a vehicle fuel tank vent and a vapor
recovery canister in a vehicle fuel tank containing liquid fuel,
said valve comprising: a housing having a fuel tank side and a
vapor recovery canister side; and a cone shaped, vapor permeable
membrane fixed to said vapor recovery canister side to block
passage of liquid fuel.
15. A valve for use between a vehicle fuel tank vent and a vapor
recovery canister in a vehicle fuel tank containing liquid fuel,
said valve comprising: a housing having a fuel tank side and a
vapor recovery canister side; and a cylindrical, vapor permeable
membrane fixed to said vapor recovery canister side to block
passage of liquid fuel.
16. The valve of claim 14 wherein said vapor permeable membrane is
a double layer material.
17. The valve of claim 15 wherein said vapor permeable membrane is
a double layer material.
18. The valve of claim 14 wherein said vapor permeable membrane Is
an acrylic copolymer material on a polyamide support.
19. The valve of claim 15 wherein said vapor permeable membrane is
an acrylic copolymer material on a polyamide support.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an improved fuel tank vent
assembly. More specifically, the present invention is directed to a
vehicle fuel tank vent assembly that has no moving parts and
provides a durable, inexpensive, vent that will not permit liquid
fuel to leak out of the tank in the case of a vehicle rollover.
BACKGROUND OF THE INVENTION
[0002] When a vehicle's fuel tank is filled with liquid fuel at the
gas station by means of the typical fuel pump nozzle, fuel vapor
above the liquid fuel in the interior of the fuel tank is displaced
as the fuel level increases. Obviously, this vapor must be vented
for the tank to be filled. Because it is undesirably to vent fuel
vapor directly into the atmosphere, modern vehicles all employ a
vapor recovery system that in its most simplistic form consists of
a vent hole in the tank connected via a tube to a vapor recovery
canister.
[0003] As early vapor recovery systems came into use, it was
discovered that a valve of some kind had to be incorporated between
the vent hole and the vapor recovery system. Such a valve is
necessary because vapor recovery canisters are inundated by liquid
fuel that splashes out of a full fuel tank, and, more
significantly, liquid fuel would drain out of the fuel tank
creating a significant fire hazard in the case of a vehicle
rollover.
[0004] A variety of fuel vent valves have been developed to address
this problem. Such valves are described in U.S. Pat. Nos.
4,966,299; 6,591,857; and 6,634,341. These vent valves employ all
manner of floats, springs, and combinations thereof that work to
partially or completely close the fuel vent to prevent splashing
fuel from entering the vapor recovery system and to completely seal
the fuel vent in case of vehicle rollover.
[0005] All mechanical floats, springs, and combinations suffer from
similar problems. They are mechanical devices involving moving
parts, and they a failure rate depending on assembly failure,
material failure, temperature, humidity, wear, etc. of these
parts.
SUMMARY OF THE INVENTION
[0006] One object of the present invention is a simplified fuel
vent that has minimal moving parts.
[0007] Another object of the present invention is a fuel vent that
is resistant to failure and inexpensive to manufacture.
[0008] These and other objects of the invention are satisfied by a
valve for use between a vehicle fuel tank vent and a vapor recovery
canister, where such a valve comprises: a housing having a fuel
tank side and a vapor recovery canister side; and a vapor permeable
membrane fixed to the housing to block the passage of liquid
fuel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is cutaway side view of a preferred embodiment
illustrating a pleated, conical, vapor permeable membrane.
[0010] FIG. 2 is a longitudinal cross section of the embodiment
shown in FIG. 1, showing a bottom view of the pleated, conical,
vapor permeable membrane.
DETAILED DESCRIPTION
[0011] A valve according to the invention for use between a vehicle
fuel tank vent and a vapor recovery canister in a vehicle fuel tank
containing liquid fuel represents a major improvement over the
prior art because it has no moving parts.
[0012] In its most basic form, a valve according to the present
invention comprises a housing formed using the minimum number of
injection molded, blow molded, cast, etc. components that are then
snapped, bonded, or welded together. A vapor permeable membrane
that allows passage of air and fuel vapor, but uses the surface
tension of the fluid to prevent its passage is fixed in the housing
to block the passage of liquid fuel. The pore size of such material
is preferably 0.2 to 5.0 microns; more preferably 0.45 to 0.80
microns; and most preferably 0.45 to 0.80 microns. Preferably, the
housing is configured to permit mounting of the vapor permeable
membrane so that the membrane is protected from fuel splashing.
[0013] The preferred vapor permeable membrane is an acrylic
copolymer on a woven or non-woven polyamide (nylon) support. Such
material is available from the Pall Corporation and is sold under
as Versapor.RTM. membrane material. Vapor permeable materials such
as polytetraflouroethane on woven or non-woven nylon
(Gore-Tex.RTM.) are also adaptable for use in the present
invention.
[0014] In order to increase the surface area of the vapor membrane,
it is preferred that the membrane be pleated. Without wishing to be
bound by theory, it is the inventor's belief that the most
efficient shape for the membrane is a pleated cone suspended in the
housing with the narrowest portion of the cone facing toward the
fuel tank. Such a configuration has a number of advantages.
Pleating increases membrane surface area. The cone shape is easy to
insert in the housing simplifying assembly. And the natural
compression of the vapor at the upper part of the cone farthest
from the fuel tank helps the vapor rapidly diffuse through the
membrane.
[0015] A number of alternative embodiments are possible depending
on the membrane type, size, positioning, etc.; fuel type; average
ambient temperature; etc. Such embodiment may employ for example, a
cylindrical and pleated membrane, a double layer membrane of
material having the same pore size, or a double layer of membrane
material having different pore sizes.
[0016] Turning to the Figures where like numbers refer to like
parts. FIGS. 1 and 2 illustrate a preferred embodiment of a valve
according to the present invention having a housing 10 roughly in
the shape of a cylinder. The housing 10 has a fuel tank side 12 and
vapor recovery side 13. A flange 14 surrounds the upper perimeter
of the housing and supports the vent when it is inserted into a
vent hole in a fuel tank. The flange may be secured to the fuel
tank using welding (such as ultrasonic welding), bonding (using
adhesive), or appropriate fasteners (screws, bolts, rivet, brads,
etc.). Fixed in the housing 10 is a conically shaped pleated
membrane 20. The membrane 20 is fixed at the recovery side 13 via
an upper support 16 having vapor air passages 18. (Alternatively,
the upper support 16 could consist of a ring of material.)
[0017] At the fuel tank side 12, the narrower portion of the
conically shaped pleated membrane may narrow to a point, or be
sealed at the edge 23 using a circular plate of appropriate
material. Fuel vapor enters the space 15 between the housing 10 and
the membrane 20. This arrangement suspends the membrane 20 inside
the housing 10 presenting the maximum area of the membrane sides 21
for diffusion of fuel vapor while preventing sloshing or splashing
liquid fuel from impacting the membrane sides 21. A port 30 at the
recovery side 13 connects the vent to the vapor recover canister
(not shown).
[0018] While there are no evaporative emission regulations for
diesel fuel, vapor recovery canisters are not used in diesel
vehicles. But there is still a need a need in such vehicles to vent
vapors during refueling events, during hot soak conditions when
vapor is formed, and to prevent fuel leakage during rollover
incidents. For these reasons, valves according to the present
invention are also useful in fuel systems for diesel vehicles.
[0019] Rollover valves, of course, also allow air into the tank to
compensate for the volume of fuel used by the engine. In a diesel
system lacking the vapor recovery canister, the valve is exposed
directly to the air. In order to prevent dirt from being ingested
into the ball, float, etc. mechanism of a standard rollover valve
and then into the tank, many diesel vehicles additionally include a
filter on their exterior surface to remove particles from this
reverse flow air. Since the fine pore sizes of the vapor permeable
membrane of the present invention effectively filter air entering
the tank as well as allowing the escape of vapor, the additional
cost and complication of a second filter is eliminated in diesel
applications.
[0020] It is to be understood that although the invention has been
described with particular reference to specific embodiments, the
forms of the invention shown and described are to be taken as a
non-limiting embodiment and various changes and modifications, such
as the development of new and better vapor permeable materials, may
be made to the invention without departing from its spirit and
scope as described in the Claims.
* * * * *