Patent Application
20130048639
The present invention relates to a fuel cap for a motor vehicle and more particularly provides a fuel cap that cannot be removed while the fuel tank is pressurized.
Modern motor vehicles, particularly hybrid vehicles, may utilize a sealed fuel system as a strategy to limit evaporative emissions. Once sealed, the fuel system is subject to internal pressure changes from changes in temperature. If the vehicle user removes the fuel cap while the system is pressurized, fuel vapor escapes into the atmosphere.
The prior art has proposed a system in which the vehicle user presses a button when the vehicle is to be refueled. Pressing the button initiates a process in which the fuel tank is depressurized by venting the fuel vapor pressure through a hydrocarbon capturing system so that fuel vapor is not vented into the atmosphere.
The prior art has also proposed that a latch be installed on the fuel filler door, and this latch will not release until the hydrocarbon capturing system has completed its process of depressurizing the fuel tank. After the fuel vapor pressure is relieved and reaches the same pressure as the atmosphere, the fuel filler door is unlocked, so that the user can open the fuel filler door and unscrew the fuel cap.
A fuel cap for a filler neck on a fuel tank includes a cap body having threads for engaging the filler neck when the fuel cap is installed on the filler neck and a cap handle rotatably mounted on the cap body. A clutch acts between the cap handle and the cap body to permit the cap handle to rotate freely on the cap body when the clutch is disengaged. When the clutch is engaged, rotation of the cap handle will rotate the cap body so that the user can remove the fuel cap from the filler neck to refuel the vehicle. A pressure-sensing diaphragm disengages the clutch when the pressure differential between the fuel vapor pressure and the atmospheric pressure exceeds a predetermined threshold and engages the clutch when the pressure differential between the fuel vapor pressure and the atmospheric pressure is less than the predetermined threshold.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the invention, are intended for purposes of illustration only and do not limit the scope of the invention.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of certain exemplary embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or uses.
Referring to
A clutch mechanism, generally indicated at 42, acts between the handle 12 and the body 14 to selectively clutch the handle 12 to the body 14, or unclutch the handle 12 from the body 14. Thus, when the clutch mechanism 42 is engaged, rotating the handle 12 will also rotate body 14. However, when the clutch mechanism 42 is disengaged, the handle 12 will freewheel relative the body 14 so that the vehicle user cannot remove the fuel cap 10 from the filler neck.
The clutch mechanism 42 includes a plurality of clutch teeth 46 that are molded on the interior of the tubular wall 18 of the body 14. The clutch mechanism 42 also includes a clutch plate 50 that is movably mounted within the handle 12 and has a plurality of clutch teeth 52 molded thereon for engagement and disengagement with respect to the clutch teeth 46 of the body 14. The clutch plate 50 has an outer rim 54 that slides on the interior of the tubular wall 18 of the body 14. The clutch plate 50 also has a pair of guide pins 58 and 60 that extend upwardly from and closely captured respectively within tubular sleeves 62 and 64 that depend from the handle 12. The capture of the guide pins 58 and 60 within the tubular sleeves 62 and 64 connects the clutch plate 50 and the handle 12 in a manner by which the rotation of the handle 12 will always rotate the clutch plate 50, and the clutch plate 50 is allowed to move up and down within the handle 12.
A diaphragm assembly, generally indicated at 68, is provided for moving the clutch plate 50 up and down to engage or disengage the clutch mechanism 42. As seen in
The clutch plate 50 has an indicator post 90 that extends upwardly from the clutch plate 50. As seen in
During normal operation of the vehicle, the fuel tank is pressurized and the pressure that exists within the fuel tank is greater than the ambient atmospheric pressure. The fuel vapor pressure within the fuel tank is communicating with the underside of the diaphragm 70. The upper side of the diaphragm 70 is exposed to the atmospheric pressure through vent passages including vent passages 102 in the body 14, vent passages 104 in the clutch plate 50, and also through the window opening 94.
In
When the fuel tank is depressurized, typically by venting the fuel tank pressure through a hydrocarbon capturing system, the pressure within the fuel tank will become equalized or nearly equalized with the ambient atmospheric pressure. Accordingly, there is no longer a pressure differential acting on the pressure sensing diaphragm 70. The coil compression spring 98, acting downwardly on the clutch plate 50 will urge the clutch plate 50 and the diaphragm 70 downwardly so that the clutch teeth 52 of clutch plate 50 will become engaged with the clutch teeth 46 of the clutch body 14, as shown in
Referring again to
It will be understood that the spring force of the coil compression springs 98 and 84 can be adjusted to set threshold pressure at which the clutch mechanism 42 will engage and disengage. In addition, it will be understood that the diaphragm 70 is free to withdraw to its position of
Thus, it is seen that the invention provides a new and improved fuel cap for a motor vehicle in which a clutch mechanism is provided inside the fuel cap to prevent removal of the fuel cap until the pressure within the tank is reduced to be at or near the ambient atmospheric pressure.
Although the drawings herein show a particular embodiment for carrying out the invention, alternative structures are within the scope of the claims. For example, the drawings herein show the clutch plate movably mounted on the handle 12 and having clutch teeth moving into engagement with fixed clutch teeth provided on the body. As an alternative, the movable clutch plate could be mounted for up and down movement on the body 14, and the fixed gear teeth could be provided on the handle. In addition, although the drawings herein show the diaphragm 70 mounted on the body 14, the diaphragm 70 could be mounted within the handle 12, above the clutch plate, for pulling the clutch plate up and down between its engaged and disengaged positions.
