The present disclosure relates to fuel tank vent valves, and particularly to venting apparatus for regulating discharge of fuel vapor from a fuel tank and admission of outside air into the fuel tank. More particularly, the present disclosure relates to a fuel tank pressure regulator including a fuel tank vent valve.
Vehicle fuel systems include valves associated with a fuel tank and configured to vent pressurized or displaced fuel vapor from the vapor space in the fuel tank to a fuel-vapor recovery canister located outside of the fuel tank. The canister is designed to capture and store hydrocarbons entrained in fuel vapors that are displaced and generated in the fuel tank during a typical vehicle refueling operation or that are otherwise vented from the fuel tank.
The vapor recovery canister is also coupled to a vehicle engine and to a purge vacuum source. Typically, vacuum is applied to the vapor recovery canister by the purge vacuum source whenever the vehicle engine is running in an effort to suck hydrocarbons captured and stored in the canister into the engine for combustion.
A tank venting system in accordance with the present disclosure includes a housing, a carbon bed located in a storage cavity defined by the housing, and a fuel tank isolation valve for regulating flow of fuel vapor between a fuel tank and the housing in a vehicle. The housing, or fuel-vapor recovery canister, is in fluid communication between the fuel tank and an engine in the vehicle to remove hydrocarbons in the fuel vapor flowing into and out of the fuel tank. The flow of fuel vapor is controlled to maintain the pressure of fuel vapor in the fuel tank at a certain pressure level or within a certain pressure range.
In the illustrative embodiments, the housing includes a media storage body formed to define a storage cavity that contains the carbon bed and a storage body closure that couples to the media storage body to close an opening to the storage cavity. The media storage body closure or cover is formed to include a cover panel that couples to the media storage body and a valve housing that extends from the cover panel.
In the illustrative embodiment, the valve housing is formed to define a vapor port in fluid communication with a fuel tank and a vapor-transfer passageway. The vapor-transfer passageway interconnects the storage cavity and the vapor port in fluid communication to transfer fuel vapor flowing to and from the fuel tank through the vapor port to the storage cavity of the media storage body. The fuel tank isolation valve of the tank venting system is located in the vapor-transfer passageway so as to regulate flow of fuel vapor in the vapor-transfer passageway between the vapor port and the storage cavity of the media storage body.
Additional features of the present disclosure will become apparent to those skilled in the art upon consideration of the following detailed description of illustrative embodiments exemplifying the best mode of carrying out the invention as presently perceived.
The detailed description particularly refers to the accompanying figures in which:
For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to a number of illustrative embodiments illustrated in the drawings and specific language will be used to describe the same.
An illustrative fuel tank venting system 10 comprises a housing 12, a carbon bed 14 located in a storage cavity 32 of the housing 12, and a fuel tank isolation valve 16 associated with that housing 12 as suggested in
Storage body closure 22 is formed to include a cover panel 24 and a valve housing 26 as shown in
Vapor-transfer passageway 30 is arranged to interconnect storage cavity 32 and vapor port 28 to enable transfer fuel vapor flowing from fuel tank 18 through vapor port 28 to storage cavity 32 of media storage body 20 and to enable transfer of hydrocarbon-laden vapor flowing from storage cavity 32 of media storage body 20 through vapor port 28 to fuel tank 18. Fuel tank isolation valve 16 of tank venting system 10 is located in vapor-transfer passageway 30 so as to regulate flow of fuel vapor in vapor-transfer passageway 30 between vapor port 28 and storage cavity 32 of media storage body 20. Fuel tank isolation valve 16 is used onboard a vehicle (not shown) including an engine and a purge vacuum source (not shown) coupled to the engine and the media storage body.
Housing 12 is a carbon canister in the illustrative embodiment and includes carbon bed 14 in storage cavity 32 to remove hydrocarbons in the fuel vapor flowing into and out of media storage body 20. Storage body closure 22 is molded to include valve housing 26 so that vapor-transfer passageway 30 is in direct fluid communication with storage cavity 32 as shown in
Vapor-transfer passageway 30 is arranged to interconnect storage cavity 32 and vapor port 28 in fluid communication to transfer fuel vapor flowing to and from fuel tank 18 through vapor port 28 to storage cavity 32 of media storage body 20. Fuel tank isolation valve 16 is located in vapor-transfer passageway 30 formed in valve housing 26 to normally to isolate fuel tank 18 from media storage body 20 to block flow of the fuel vapor between tank 18 and media storage body 20.
In vehicles with a normal internal combustion engine, the fuel vapor from the fuel tank is vented directly to the surrounding atmosphere. Directly venting the fuel vapor to the surrounding atmosphere may be harmful to people and/or the environment.
However, in partially hybrid electric vehicles (PHEV), the internal combustion engine included in the vehicle operates intermittently and therefore the fuel tank system is frequently closed off from the atmosphere when not in use (i.e. the engine is not being used). Closing the system off from the atmosphere may reduce the harmful emissions to the surrounding environment, but may create a need to control/regulate the fuel vapor in the system.
The fuel vapor in the fuel tank may therefore be at a higher pressure or a lower vacuum pressure than normal engines, which may make opening fuel system lines when ready for use a challenge. Further, if the increased pressure in the fuel tank is not released, the fuel tank may become damaged or even explode.
Fuel tank systems may include a fuel tank isolation valve to control the flow fuel vapor and air between the fuel tank and a canister used to store the pressurized fuel vapor to release built up pressure in the fuel tank at different stages. The canister is configured to “clean” fuel vapor vented from the fuel tank during tank refueling. The canister may be in fluid communication with the engine, the fuel tank, and the atmosphere, which provides several leak paths for the fuel vapor.
In the illustrative embodiment, valve housing 26 in the storage body closure 22 integrates fuel tank isolation valve 16 in housing 12 to eliminate leak paths between fuel tank 18 and engine. Fuel vapor from fuel tank 18 flows through vapor port 28, through vapor-transfer passageway 30, and directly into storage cavity 32. An opening 31 to vapor-transfer passageway 30 opens directly into storage cavity 32 to put vapor-transfer passageway 30 in direct fluid communication with storage cavity 32. In the illustrative embodiment, an inner wall 36 of valve housing 26 defines opening 31 to vapor-transfer passageway 30.
Housing 12, or fuel-vapor recovery canister, includes media storage body 20 and storage body closure 22 as shown in
Housing 12 is also formed to define an atmosphere vapor port 23 and an engine vapor port 25 as shown in
In some embodiments, storage body closure 22 may be formed to define atmosphere vapor port 23 and engine vapor port 25. In other embodiments, media storage body 20 may be formed to define atmosphere vapor port 23 and engine vapor port 25. In the illustrative embodiment, media storage body 20 is formed to define one of the atmosphere vapor port 23 or the engine vapor port 25, while storage body closure 22 is formed to define the other.
Storage body closure 22 is formed to include cover panel 24 and valve housing 26 as shown in
Valve housing 26 is formed to define vapor port 28 and vapor-transfer passageway 30 as shown in
Valve housing 26 includes an outer wall 34, an inner wall 36, and a vapor pipe 38 as shown in
In the illustrative embodiment, vapor-transfer passageway 30 extends along axis 39A of fuel tank isolation valve 16, while vapor pipe 38 extends at an angle relative to vapor-transfer passageway 30 as shown in
Fuel tank isolation valve 16 regulates fuel vapor flow through vapor-transfer passageway 30 to regulate pressure of fuel vapor within fuel tank 18 in accordance with predetermined pressure targets. Fuel tank isolation valve 16 includes a stationary perforated partition plate 40 mounted in vapor-transfer passageway 30 and a multi-stage flow controller 42 that is mounted for movement in vapor-transfer passageway 30 alongside and relative to perforated partition plate 40 as shown in
Perforated partition plate 40 is arranged to divide vapor-transfer passageway 30 into a storage-side chamber 44 that communicates directly with storage cavity 32 of media storage body 20 and an overlying tank-side chamber 46 that communicates with vapor port 28 as shown in
In the illustrative embodiment, perforated partition plate 40 is formed to include a round central vent aperture 48 centered on central vertical axis 39A and six arc-shaped orbital vent apertures 50a-f arranged to surround the round central vent aperture 48 and lie in radially spaced relation from central vertical axis 39A and circumferentially spaced-apart relation to one another. Perforated partition plate 40 is mounted in a stationary position in the vapor-transfer passageway 30 of valve housing 26.
In the illustrative embodiment, perforated partition plate 40 is arranged within inner wall 36. Perforated partition plate 40 is located in the vapor-transfer passageway 30 defined by the inner wall 36 of the valve housing 26.
In the illustrative embodiment, cover panel 24 and valve housing 26 of storage body closure 22 are a monolithic component of plastic material. Cover panel 24 and valve housing 26 of storage body closure 22 and stationary perforated partition plate 40 of fuel tank isolation valve 16 are a monolithic component. In the illustrative embodiment, outer wall 34, inner wall 36, and vapor pipe 38 of valve housing 12 along with cover panel 24 and stationary perforated partition plate 40 are a monolithic component.
In the illustrative embodiment, the fuel tank isolation valve 16 includes a solenoid 42 for use with multi-stage flow controller 42 as suggested in
Perforated partition plate 40 of fuel tank isolation valve 16 is located in vapor-transfer passageway 30 formed in housing 12 as shown in
Multi-stage flow controller 42 is configured normally to engage perforated partition plate 40 to close the first and second vents 48, 50 formed in perforated partition plate 40 so as to block fuel vapor flow from vapor port 28 to storage cavity 32 through the vapor-transfer passageway 30 formed housing 12 so that fuel tank 18 is normally isolated from fluid communication with storage cavity 32 of media storage body 20. However, multi-stage flow controller 42 is configured in to disengage from perforated partition plate 40 in several different ways so as to regulate flow of fuel vapor in vapor-transfer passageway 30 between fuel tank 18 and storage cavity 32 of media storage body 20 independently through central vent aperture 48 and also through several orbital vent apertures 50a-f during (1) early and later stages of fuel tank 18 refueling activity, (2) development of unwanted vacuum conditions in fuel tank 18, and (3) development of unwanted over-pressure conditions in fuel tank 18.
Multi-stage flow controller 42 includes a tank-side vapor-flow regulator 42T and a storage-side vapor-flow regulator 42S as suggested in
Multi-stage flow controller 42 also includes a spring-biased movable armature 42A that is operationally coupled to solenoid 42 and is arranged to extend into the vapor-transfer passageway 30 as shown in
Tank-side and storage-side vapor-flow regulators 42T, 42S are configured to move in the vapor-transfer passageway 30 relative to the stationary perforated partition plate 40 to close, partly open, and open vents 48, 50 formed in perforated partition plate 40 in response to changes in pressure of fuel vapor extant in the vapor-transfer passageway 30 and in fuel tank 18. Movable armature 42A is spring-biased normally to move toward storage-side vapor-flow regulator 42S and is operationally linked to solenoid 42 to move upwardly away from storage-side vapor-flow regulator 42S when solenoid 42 is energized. Movable armature 42A includes a distal tip 42AT that is arranged to extend into the vapor-transfer passageway 30 and move therein in response to a pushing force generated by an armature-biasing spring 42AS and actuation of solenoid 42 to assume various positions therein to cooperate with storage-side vapor-flow regulator 42S so as to close or partly open the central vent 48 formed in the perforated partition plate 40.
As mentioned above, fuel tank isolation valve 16 may be important to regulate the pressure of fuel vapor in the system of hybrid vehicles. Fuel tank isolation valve 16 is normally closed to block the flow of fuel vapor from tank 18 to media storage body 20 as shown in
In the case of over-pressure conditions, valve 16 changes to one of the open modes to allow a release a large amount of pressure from fuel tank 18. Conversely, if there is vacuum conditions in fuel tank 18, fuel tank isolation valve 16 may change to another opened mode to alleviate unwanted vacuum conditions. Once the vehicle switches to using engine, fuel tank isolation valve 16 may change to one of open modes to allow the fuel vapor to flow from fuel tank 18 through media storage body 20 and to the engine to be burned with the fuel.
Releasing the built up pressure of the fuel vapor in the fuel tank may also be important during refueling of the fuel tank. When a person uses a fuel-dispersion pump nozzle to begin to discharge fuel into a filler neck leading to the fuel tank, fuel tank isolation valve 16 changes from closed mode to first opened mode to vent some displaced fuel vapor from fuel tank 18. After refueling begins and fuel is being discharged at a constant rate into fuel tank 18, fuel tank isolation valve 16 changes to second opened mode to vent more displaced fuel vapor.
As suggested in
Bottom mount member 62 is independent of housing 12. Bottom mount member 62 is located in an opening 31 of vapor-transfer passageway 30 that opens directly into storage cavity 32 to provide a shoulder surface 62S. Shoulder surface 62S is engaged by other components of fuel tank isolation valve 16 to retain fuel tank isolation valve 16 in the opening of vapor-transfer passageway 30.
Bottom mount member 62 is located in the vapor-transfer passageway 30 below the compression spring 58 and spring cap 60 so that the spring 58 engages with the bottom mount member 62 to bias the spring cap 60 with the O-ring seal 60S into engagement with the underside of perforated partition plate 40. The bottom mount member 62 is shaped to include a hole 64 that opens into storage cavity 32 and vapor-transfer passageway 30 so as to allow pressurized fuel vapor to flow through bottom mount member 62. In some embodiments, bottom mount member 62 may be fixed to housing 12 in vapor-transfer passageway 30 of housing 12.
As suggested in
The installation of movable armature 42A, spring 42AS, and tank-side vapor-flow regulator 42T causes a downwardly extending tip 42AT of movable armature 42A to extend along the single vertical axis 39A into the first vent 48 established by central vent aperture 48 and formed in perforated partition plate 50. The installation of movable armature 42A, spring 42AS, and tank-side vapor-flow regulator 42T also causes seal ring 66 of tank-side vapor-flow regulator 42T to engage an annular outer perimeter region of topside of perforated partition plate 50 to block fuel vapor from passing through the second vent 50 established by six orbital vent apertures 50a-f (see
Storage-side vapor-flow regular 42S is installed through opening 31 of vapor-transfer passageway 30. Spring cap 60 and spring 58 are inserted into the storage-side chamber 44 and bottom mount member 62 is then inserted into opening 31 of vapor-transfer passageway 30 and fixed to inner wall 38 of valve housing 26. The installation of storage-side vapor-flow regular 42S causes O-ring seal 60S of storage-side vapor-flow regulator 42S to engage the downwardly facing surface on distal tip 42AT of movable armature 42A and the downwardly facing surface on the annular inner perimeter region of underside of perforated partition plate 50 that surrounds the central vent aperture 48. Then storage body closure 22 is coupled to media storage body 20 to close off top opening 32O of storage cavity 32.
Tank venting system 10 includes housing 12, carbon bed 14, and fuel tank isolation valve 16 as shown in
Storage body closure 22 includes cover panel 24 that couples to storage body 20 and valve housing 26 that extends from cover panel 24. Valve housing 26 is formed to define vapor port 28 in fluid communication with fuel tank 18 and vapor-transfer passageway 30 arranged to interconnect storage cavity 32 and vapor port 28 to enable transfer of fuel vapor flowing from fuel tank 18 through vapor port 28 to storage cavity 32 of media storage body 20 and to enable transfer of hydrocarbon-laden vapor flowing from storage cavity 32 of media storage body 20 through vapor port 28 to fuel tank 18.
Cover panel 24 and valve housing 26 of storage body closure 22 are a monolithic component. In some embodiments, cover panel 24 and valve housing 26 of storage body closure 22 are a monolithic component of plastic material in the illustrative embodiment.
Cover panel 24 may be coupled to storage body 20 with fasteners in some embodiments. In other embodiments, cover panel 24 may be welded to storage body 20. In other embodiments, another suitable method of fixing cover panel 24 to storage body 20 may be used.
Carbon bed 14 is located in storage cavity 30 of media storage body 20. Carbon bed 14 is configured to absorb hydrocarbons in the fuel vapor flowing into and out of media storage body 20 through vapor-transfer passageway 30.
Fuel tank isolation valve 16 is located in vapor-transfer passageway 30 of storage body closure 22. Fuel tank isolation valve 16 is configured to regulate flow of fuel vapor in vapor-transfer passageway 30 between vapor port 28 and storage cavity 32 of media storage body 20.
Valve housing 26 includes outer wall 34, inner wall 36, and vapor pipe 38 as shown in
Fuel tank isolation valve 16 includes stationary perforated partition plate 40 located in vapor-transfer passageway 30 defined by inner wall 36 of valve housing 26 as shown in
Fuel tank isolation valve 16 further includes storage-side vapor-flow regulator 42S and a tank-side vapor-flow regulator 42T as shown in
Bottom mount member 62 is independent of storage body closure 22 in the illustrative embodiment. Bottom mount member 62 is located in bottom opening 31 of vapor-transfer passageway 30 that opens directly into storage cavity 32. Bottom mount member 62 provides shoulder surface 62S that is engaged by other components of fuel tank isolation valve 16 to retain fuel tank isolation valve 16 in storage-side chamber 44 of vapor-transfer passageway 30.
In the illustrative embodiment, bottom mount member 62 is formed to include a annular lip 62L as shown in
This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application Ser. No. 63/257,084, filed Oct. 18, 2021, which is expressly incorporated by reference herein.
Number | Date | Country | |
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63257084 | Oct 2021 | US |