Patent Application
20070151628
The present invention generally relates to fuel storage systems and in particular, to a fuel tank cap.
It is known in fuel storage and delivery that it is commonly necessary to vent a fuel tank to relieve vapor pressure build-up which may occur when the fuel tank cap is in place and to permit the escape of air during normal filling operations when the fuel tank cap is removed. Thus, it is known to use an evaporative control system. A typical evaporative control system vents fuel vapor to a vapor storage canister, such as a carbon canister. It is also important to ensure that fuel vapors and/or raw fuel from the tank do not flood the canister during normal engine operation or during filling. Conventional designs for evaporative control systems seek to minimize the canister volume by protecting against fuel tank vapor generation and increasing engine purging of the canister.
Until recently, evaporative emission controls were generally not required for use in connection with small engine fuel tanks. However, current environmental control laws and regulations may now require that fuel tank systems for small engines include safeguards to prevent the excessive escape of fuel vapors under normal operating conditions and to prevent the escape of raw fuel from the tank in the event of a roll inversion. The compact size of such engines can create a particular challenge.
The present invention recognizes some of these and other problems associated with evaporative emissions systems. To this end, a fuel tank cap is provided comprising a liquid protected vapor storage receptacle. The liquid protected vapor storage receptacle includes absorbent granulated carbonaceous material. In another embodiment, a fuel storage system is provided comprising a filler tube connected to a fuel storage tank on one end and having an inlet opening on an opposite end and a fuel tank cap capable of sealingly engaging the inlet opening. The fuel tank cap includes a means for storing fuel vapors.
Referring to
Referring now to
In an installed embodiment, partially threaded surface 18c of fuel tank cap 18 can engage inlet opening 16, which can result in effectively securing fuel tank cap 18 to filler tube 14. A seal 20 may be provided between filler tube 14 and fuel tank cap 18, effectively sealing filler tube 14 and fuel tank 12 from the atmosphere. In such a configuration, the internal pressure in fuel storage tank 12 and filler tube 14 is generally greater than the atmospheric pressure.
Fuel tank cap 18 may further include a means for storing fuel vapors, generally comprising a vapor storage receptacle, such as the illustrated integrated vapor storage receptacle 21. Vapor storage receptacle 21 includes an outer shell, or canister 22. Canister 22 may be packed tightly with an absorbent granulated carbonaceous material, such as, for example, carbon pellets, charcoal, or the like, as is known in the art. The absorbent granulated carbonaceous material may be packed using screens, or filters 28. Further, if desired, a spring loaded volume compensator plate (not shown) may be used to continually push upon the filters 28 to keep the absorbent granulated carbonaceous material in place. Among other things, canister 22 may function as a storage receptacle for fuel vapors and to absorb hydrocarbons which escape from the fuel storage tank 12. Such hydrocarbons can then be combusted back into the engine.
The vapor storage receptacle 21 may be connected or attached to the inner surface 18b of the fuel tank cap 18, within cavity 19. When fuel tank cap 18 is installed, vapor storage receptacle 21 extends downwardly towards fuel storage tank 12. Canister 22 can be generally cylindrical in shape and have a diameter smaller than the diameter of inlet opening 16. However, it can be appreciated that canister 22 may be any particular shape and dimension, so long as fuel tank cap 18 can be disengaged and removed from inlet opening 16, such as during a refueling process, without causing an unacceptable level of interference between fuel tank cap 18 and inlet opening 16.
Vapor storage receptacle 21 may be integrated to fuel tank cap 18 by various methods. As illustrated, vapor storage receptacle 21 can be integrated into fuel tank cap 18 by snap-fitting a portion 17 of vapor storage receptacle 21 into an aperture 23 located on fuel tank cap 18. Alternatively, without limitation, vapor storage receptacle 21 may be integrated into or otherwise connected to the fuel tank cap 18 by threaded engagement, or by welding, such as, for example, ultrasonic welding, spin welding, electro-mechanical welding, or the like. In a further embodiment, the vapor storage receptacle 21 may be integrated into or connected to the fuel tank cap 18 by a friction fit forming between the canister 22 of the vapor storage receptacle 21 and the partially threaded surface 18c of the fuel tank cap 18. It should be noted, in certain situations, such as those illustrated in
However, it can be appreciated by those skilled in the art that vapor storage receptacle 21 may be integrated into or connected to fuel tank cap 18 by any number of methods known in the art, so long as vapor storage receptacle 21 can be connected or attached to inner surface 18b of fuel tank cap 18. For instance, both inner surface 18b and canister 22 may have corresponding threaded surfaces, and as a result, vapor storage receptacle 21 may be integrated to fuel tank cap 18 by screwing the two components together. Further, both the fuel tank cap 18 and the carbon canister 22 may be comprised of a plastic material.
Canister 22 may include an purge line 24 that may be operatively connected to a component of an engine, such as an intake of the engine (not shown). As generally illustrated in the Figures, purge line 24 may also serve as a tether for fuel tank cap 18, which, among other things, may prevent fuel tank cap 18 from being misplaced or lost.
Canister 22 may further include an air inlet, or air aperture 25, covered by a selectively permeable membrane 28. Aperture 25 may be in communication with an aperture 27 on fuel tank cap 18. Aperture 25 allows canister 22 to be open to the atmosphere, while membrane 28 prevents the absorbent granulated carbonaceous material from escaping from canister 22. Aperture 25 and membrane 28 allow atmospheric air to enter canister 22 and amongst other things, refresh the absorbent granulated carbonaceous material.
It can be appreciated that aperture 27 may be located anywhere on fuel tank cap 18 and membrane 28 may be located anywhere on canister 22, so long as aperture 25 and membrane 28 are capable of being operatively engaged and allow canister 22 to be open to the atmosphere. Further, it can be appreciated that the threaded engagement of fuel tank cap 18 with filler tube 14 may allow atmospheric air into cavity 19, thereby serving as an air inlet.
Fuel storage system 10 may further include a check valve 30 within a conduit 36, located along filler tube 14 and proximate to inlet opening 16. Conduit 36 may connect filler tube 14 to a vapor compartment 66. When the fuel tank cap 18 is replaced, after refueling, check valve 30 is actuated to an open position allowing trapped air to be returned from attached vapor compartment 66, thereby allowing liquid in filler tube 14 to retract, creating a vented vapor space to communicate with canister 22. Check valve 30 remains actuated, or in an open position, when fuel tank cap 18 is properly engaged to inlet opening 16 and deactuated, or in a closed position, when fuel tank cap 18 is removed from inlet opening 16.
As generally illustrated in
Referring now to
Fuel tank cap 18 may further include a means for protecting vapor storage receptacle 21 from liquid fuel, such as a liquid discriminator valve, a vapor vent valve, or a rollover valve, or the like. In an illustrated embodiment, the means for protecting vapor storage receptacle 21 is generally shown in the form of a rollover valve 44. The rollover valve 44 may be partially disposed within and operatively engaged to vapor storage receptacle 21. Rollover valve 44 may act as a liquid fuel and fuel vapor discriminator, essentially allowing fuel vapors to enter vapor storage receptacle 21 while preventing liquid fuel from entering into vapor storage receptacle 21. For example, during operation of the engine, fuel may slosh about in fuel storage tank 12 and come into contact with vapor storage canister 21, or in other instances, fuel storage tank 12 may be accidentally or intentionally turned upside down. The rollover valve 44 may prevent intrusion of liquid fuel into vapor storage receptacle 21. It can be appreciated by those skilled in the art that rollover valves are commonly known. It can be further appreciated that the invention is not limited to a rollover valve, and may include any means that protects the vapor storage receptacle from contact with liquid fuel.
Referring to
Vapor flow channel 52 may further include a seal 67, which is capable of acting as a one-way passage for atmospheric air to enter into vapor flow channel 52. Seal 67 may be inserted, or engaged, into a central aperture 65 located on vapor flow channel 52. A plurality of apertures 68, may be located along either side of seal 67, which may provide a means for atmospheric air to enter into vapor flow channel 52. Seal 67 can be configured or shaped such that seal 67 may operatively engage apertures 68 to allow atmospheric air in without allowing fuel vapors out, of vapor flow channel 52. As illustrated in
Conduit 58 may also serve as a tether to prevent the loss of fuel tank cap 50. As illustrated, conduit 58 includes a barbed, or threaded end 58a for engaging the tube connecting to the remote vapor storage receptacle. However, it can be appreciated that conduit 58 may be engaged to vapor storage receptacle by any conventional method.
As illustrated, vapor flow channel 52 may be integrated to fuel tank cap 50 by snap-fitting a pin 62 of vapor flow channel 52 into an aperture 64 in fuel tank cap 50. However, it can be appreciated that vapor flow channel 52 may be integrated into fuel tank cap 50 by methods similar to those described above for integrating vapor storage receptacle 21 to fuel tank cap 18.
The embodiments disclosed herein have been discussed for the purpose of familiarizing the reader with novel aspects of the invention. Although preferred embodiments of the invention have been shown and described, many changes, modifications and substitutions may be made by one having ordinary skill in the art without necessarily departing from the spirit and scope of the invention as described in the following claims.
