Abstract:
A tank venting system in accordance with the present disclosure includes a vent apparatus for regulating flow of fuel vapor between a fuel tank and a fuel vapor recovery system in a vehicle. 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 during different modes of use.

Description:
PRIORITY CLAIM 
       [0001]    This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application Ser. No. 62/307,113, filed Mar. 11, 2016, which is expressly incorporated by reference herein. 
     
    
     BACKGROUND 
       [0002]    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. 
         [0003]    Vehicle fuel systems include valves associated with a fuel tank and are configured to vent pressurized or displaced fuel vapor from the vapor space in the fuel tank to a 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. 
       SUMMARY 
       [0004]    A tank venting system in accordance with the present disclosure includes a vent apparatus for regulating flow of fuel vapor between a fuel tank and a fuel vapor recovery system in a vehicle. 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 during different modes of use. 
         [0005]    In illustrative embodiments, the vent apparatus includes a pressure-controlled valve configured to regulate a relatively large volume of fuel vapor flow from a fuel tank to a fuel vapor recovery canister along a first vapor flow path and an electronically-controlled pressure bleed valve configured to regulate flow of a relatively small volume of fuel vapor flow from the fuel tank to the fuel vapor recovery canister along a second vapor flow path. By regulating the relatively small volume of fuel vapor flow from the fuel tank to the fuel vapor recovery canister, the electronically-controlled pressure bleed valve adjusts pressure applied to the pressure-activated valve such that opening and closing of the pressure-activated valve is controlled by the electronically-controlled pressure bleed valve. 
         [0006]    In illustrative embodiments, the pressure-controlled valve is movable from a normally closed position arranged to block fuel vapor flow along the first vapor flow path to an opened position arranged to allow fuel vapor flow along the first vapor flow path. The pressure-controlled valve includes a deformable diaphragm that flexes in response to a pressure differential being applied to opposing sides of the pressure-controlled valve to move the pressure-controlled valve from the closed position to the opened position. A bias spring is configured to encourage the pressure controlled valve toward the normally closed position. 
         [0007]    In illustrative embodiments, the electronically-controlled valve is movable from a closed position arranged to block fuel vapor flow along the second vapor flow path to an opened position arranged to allow fuel vapor flow along the second vapor flow path. The electronically-controlled valve includes a stopper configured to move into and out of a bleed passageway and an electro-magnetic actuator configured to move the stopper. A valve-mover controller is coupled to the electro-magnetic actuator to open and close the electronically-controlled valve under predetermined conditions. 
         [0008]    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. 
     
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0009]    The detailed description particularly refers to the accompanying figures in which: 
           [0010]      FIG. 1  is a sectional perspective view of a tank venting system including a vent apparatus configured to control the flow of fuel vapor from a fuel tank to a fuel vapor recovery canister, showing that the vent apparatus comprises (1) a pressure-controlled valve configured to block or allow a relatively large volume of fuel vapor to flow from the tank passageway to the canister passageway through a first portion of a valve compartment to relieve unwanted tank pressure conditions as suggested in  FIG. 7  and (2) an electronically-controlled pressure bleed valve configured to block or allow a relatively small volume of fuel vapor to flow to atmosphere through a second portion of the valve compartment to adjust pressure in the second portion of the valve compartment and thereby control pressures applied to the pressure-controlled valve as suggested in  FIG. 6 ; 
           [0011]      FIG. 2  is an exploded sectional perspective assembly view of the components included in the vent apparatus of  FIG. 1  and showing that the vent apparatus includes (1) a multi-piece housing, (2) the pressure-controlled valve made up of a deformable diaphragm adapted to be mounted to the housing, a seal ring that seals against the housing, and a divider plate that interconnects the deformable diaphragm and the seal ring, and (3) the electronically-controlled pressure bleed valve having a movable stopper with an overmolded diaphragm and an electro-magnetic actuator configured to move the stopper from a closed position to an opened position as suggested in  FIGS. 3-6 ; 
           [0012]      FIG. 3  is a cross-sectional view of the tank venting system of  FIG. 1  with the electronically-controlled pressure bleed valve in the closed position and the pressure-controlled valve in the closed position blocking fluid flow from the fuel tank to the fuel-vapor recovery canister; 
           [0013]      FIG. 4  is an enlarged view of the circled portion of  FIG. 3  showing the stopper of the electronically-controlled pressure bleed valve in the closed position with the overmolded diaphragm blocking flow of fuel vapor from the control pipe to the canister pipe through the upper portion of the valve compartment and the bleed pipe so that pressure in the upper portion of the valve compartment included in the pressure-controlled valve housing is pressurized by the fuel tank to match the pressure in the lower portion of the valve compartment thereby maintaining the pressure-controlled valve in the closed position; 
           [0014]      FIG. 5  is view similar to  FIG. 3  with the electronically-controlled pressure bleed valve in the opened position to allow a relatively small fluid flow from the fuel tank to the fuel-vapor recovery canister while the pressure-controlled valve is in the closed position blocking a relatively large fluid flow from the fuel tank to the fuel-vapor recovery canister; 
           [0015]      FIG. 6  is an enlarged view of the circled portion of  FIG. 5  showing the stopper of the electronically-controlled pressure bleed valve in the opened position allowing flow of fuel vapor from the control pipe to the canister pipe through the upper portion of the valve compartment and the bleed pipe so that pressure in the upper portion of the valve compartment is lowered below the pressure in the lower portion of the valve compartment thereby causing the pressure-controlled valve to move to the opened position as shown in  FIG. 7 ; 
           [0016]      FIG. 7  is view similar to  FIGS. 3 and 5  with the electronically-controlled pressure bleed valve in the opened position to allow a relatively small fluid flow from the fuel tank to the fuel-vapor recovery canister and the pressure-controlled valve in the opened position allowing a relatively large fluid flow from the fuel tank to the fuel-vapor recovery canister; and 
           [0017]      FIG. 8  is an enlarged view of the circled portion of  FIG. 7  showing the electronically-controlled valve in the opened position. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    A tank venting system  10  is provided to control flow of air and fuel vapor between a fuel tank  12  and an emission control system including a fuel vapor recovery canister  14  as suggested in  FIG. 1 . System  10  is used onboard a vehicle (not shown) including an engine and a purge vacuum source coupled to engine and canister  14  as suggested in  FIG. 3 . 
         [0019]    Tank venting system  10  includes a vent apparatus  20  coupled to fuel tank  12  via a tank conduit and to fuel vapor recovery canister  14  via a canister conduit as suggested in  FIG. 1 . Vent apparatus  20  includes a multi-piece housing  22 , a pressure-controlled valve  24 , and an electronically-controlled pressure bleed valve  26 . Pressure-controlled valve  24  is configured to selectively allow a relatively large volume of fuel vapor to flow from the tank  12  to the canister  14  to relieve unwanted tank pressure conditions as suggested in  FIG. 7 . Electronically-controlled pressure bleed valve  26  is configured to selectively allow a relatively small volume of fuel vapor to flow to atmosphere  11  from housing  22  and thereby control pressures applied to pressure-controlled valve  24  as suggested in  FIG. 6 . Because electronically-controlled pressure bleed valve  26  need only control a relatively small-volume of vapor flow, the power required to control the flow is less than if controlling a relatively-large volume of flow. 
         [0020]    Multi-piece housing  22  forms various passageways for conducting gasses moving between the fuel tank  12  and the fuel vapor recovery canister  14  as suggested in  FIGS. 1 and 2 . Housing  22  illustratively includes a body  30 , a cap  32 , and a floor  34  as shown in  FIG. 2 . Body  30  provides passageways  37 ,  39  for fluidly coupling fuel tank  12  with canister  14  sized for relatively-large fuel vapor flows that are controlled by pressure-controlled valve  24 . Cap  32  is coupled to body  30  and provides passageways  45 ,  47  sized for relatively-small fuel vapor flows that are controlled by electronically-controlled valve  26 . Body  30  and cap  32  cooperate to define a valve compartment  40  that is divided into a lower portion  41  and an upper portion  42  by pressure-controlled valve  24  as shown in  FIG. 1 . 
         [0021]    Body  30  is formed to include a tank pipe  36  coupled to fuel tank  12  and a canister pipe  38  coupled to canister  14  as shown in  FIG. 2 . Tank pipe  36  defines a tank passageway  37  that fluidly interconnects tank  12  with lower portion  41  of valve compartment  40 . Canister pipe  38  defines a canister passageway  39  that fluidly interconnects a compartment pipe  35  extending from lower portion  41  of valve compartment  40  with canister  14 . Both tank passageway  37  and canister passageway  39  are sized to conduct a relatively-large fuel vapor flow. Pressure-controlled valve  24  selectively blocks or allows fuel vapor to flow through compartment pipe  35  from lower portion  41  of valve compartment  40  into canister passageway  39  of canister pipe  38  to thereby control relatively-large vapor flow as suggested in  FIGS. 3 and 7 . 
         [0022]    Cap  32  mounts to body  30  and is formed to include a valve-control pipe  44  coupled to fuel tank  12 , a bleed pipe  46  coupled indirectly to atmosphere  11 , and a valve cup  48  as shown in  FIG. 2 . Valve-control pipe  44  defines a valve pressurization passageway  45  that fluidly interconnects fuel tank  12  with upper portion  42  of valve compartment  40 . Bleed pipe  46  defines a bleed passageway  47  that fluidly interconnects upper portion  42  of valve compartment  40  with canister passageway  39  that leads through canister  14  to atmosphere  11 . Bleed passageway  47  is sized to conduct a relatively-small fuel vapor flow. Valve cup  48  receives and supports electronically-controlled valve  26 . Electronically-controlled valve  26  selectively blocks or allows fuel vapor to flow from upper portion  42  of valve compartment  40  through bleed passageway  47  to atmosphere  11  as suggested in  FIGS. 5 and 6 . 
         [0023]    A first vapor flow path provided by housing  22  is sized to conduct a relatively-large volume of fuel vapor flow as suggested in  FIG. 7 . The first vapor flow path is defined by tank pipe  36 , lower portion  41  of valve compartment  40 , compartment pipe  35 , and canister pipe  38  as shown in  FIG. 7 . Pressure-controlled valve  24  is configured to regulate flow along the first vapor flow path as suggested in  FIGS. 3 and 7 . 
         [0024]    A second vapor flow path provided by housing  22  is sized to conduct a relatively-small volume of fuel vapor flow (smaller than that carried through first vapor flow path) as suggested in  FIG. 5-8 . The second vapor flow path is defined by valve-control pipe  44 , upper portion  42  of valve compartment  40 , bleed pipe  46 , and canister pipe  38 . Electronically-controlled valve  26  is configured to regulate flow along the second vapor flow path as suggested in  FIGS. 3-8 . 
         [0025]    Pressure-controlled valve  24 , sometimes called primary valve  24 , is configured to control relatively-large flows of fuel vapor from fuel tank  12  to canister  14  and, in turn, atmosphere  11  as suggested in  FIGS. 3, 5, and 7 . Such relatively-large flows may be allowed during refueling of fuel tank  12  or during operation of a vehicle engine burning fuel from fuel tank  12 . In a closed position, pressure-controlled valve  24  blocks flow from lower portion  41  of valve compartment  40  into compartment pipe  35  thereby cutting off flow from tank pipe  36  to canister pipe  38 . In an opened position, pressure-controlled valve  24  allows flow from lower portion  41  of valve compartment  40  into compartment pipe  35  thereby opening flow from tank pipe  36  to canister pipe  38 . 
         [0026]    Pressure-controlled valve  24  illustratively includes a deformable diaphragm  50 , a seal ring  52 , and a divider plate  54  that interconnects deformable diaphragm  50  and seal ring  52  as shown in  FIG. 2 . Deformable diaphragm  50  is mounted to housing  22  by trapping deformable diaphragm  50  between body  30  and cap  32  of housing  22  and is configured to deform based upon pressure in first and second portions  41 ,  42  of valve compartment  40 . Seal ring  52  is coupled to plate  54  for movement therewith and is shaped/arranged to engage compartment pipe  35  of housing  22  when pressure-controlled valve  24  is closed. Divider plate  54  is coupled to deformable diaphragm  50  such that divider plate  54  is movable within valve compartment  40  upon deformation of diaphragm  50  to carry seal ring  52  into and out of contact with compartment pipe  35 . A bias spring  55  is arranged between divider plate  54  and cap  32  of housing  22  to encourage the divider plate  54  toward compartment pipe  35  and bias pressure-controlled valve  24  toward the closed position. 
         [0027]    Electronically-controlled valve  26  is configured to control the pressure in upper portion  42  of valve compartment  40  that is applied to pressure-controlled valve  24  so that pressure-controlled valve  24  opens and closes in response to opening and closing of electronically-controlled valve  26  as suggested in  FIGS. 3-8 . Electronically-controlled valve  26  controls relatively-small flows of fuel vapor from fuel tank to canister  14  and, in turn, to atmosphere  11  allowing valve  26  to be relatively small and easy to control. In a closed position, electronically-controlled valve  26  blocks flow through bleed passageway  47  as shown in  FIGS. 3 and 4 . In an opened position, electronically-controlled valve  26  allows flow through bleed passageway  47  as shown in  FIGS. 5-8 . 
         [0028]    Electronically-controlled valve  26  is illustratively housed in valve cup  48  of cap  32  included in the housing  22  as shown in  FIG. 1 . Electronically-controlled valve  26  includes a stopper  60  and an electro-magnetic actuator  62  as shown in  FIG. 2 . Stopper  60  is made up of an armature  64  and an overmolded diaphragm  66 . Electro-magnetic actuator  62  is electrically coupled to a valve-mover controller  68  and is configured to move stopper  60  between a closed position blocking flow through bleed passageway  47  and an opened position allowing flow through bleed passageway  47 . A return spring  65  is arranged to bias stopper  60  toward the closed position blocking fuel vapor from flowing from control pipe  46  to canister pipe  38  through housing  22 . 
         [0029]    In some embodiments, vacuum and/or pressure relief valves can be incorporated into vent apparatus  20  to accommodate fault modes of the electronically-controlled valve  26 . A vacuum relief valve may be configured to allow vapor to flow from canister  14  (and atmosphere  11 ) to tank  12  upon a large enough vacuum pressure developing in tank  12 . A pressure relief valve may be configured to allow vapor to flow from tank  12  to canister  14  (and atmosphere  11 ) upon a large enough pressure developing in tank  12 . 
         [0030]    In operation, to open the pressure-controlled valve  24  thereby allowing a relatively large flow of fuel vapor to move from tank  12  to canister  14 , an electrical signal is generated by valve-mover controller  68  associated with opening of electronically-controlled valve  26 . The electrical signal may be generated in response to a user opening an outer fuel door of a vehicle indicative that the use may be about to refuel the vehicle. Upon receipt of the electrical signal, electro-magnetic actuator  62  moves stopper  60  to allow a relatively small flow of fuel vapor from upper portion  42  of valve compartment  40  toward canister  14  and atmosphere  11  as suggested in  FIGS. 5 and 6 . 
         [0031]    The relatively small flow of fuel vapor out from upper portion  42  of valve compartment  40  reduces the pressure in upper portion  42  to a level lower than that in lower portion  41  of valve compartment  40  such that pressure-controlled valve  24  moves from its normally closed position to the open position as suggested in  FIG. 7 . When pressure-controlled valve  24  is in the opened position, a relatively-large flow of fuel vapor can move from fuel tank  12  to canister  14  and atmosphere  11 . 
         [0032]    The following numbered clauses include embodiments that are contemplated and non-limiting: 
         [0033]    Clause 1. A tank venting system adapted for use in a vehicle, the system comprising 
         [0034]    a fuel tank configured to store liquid fuel, 
         [0035]    a fuel vapor recovery canister located outside the fuel tank and configured 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, and 
         [0036]    a vent apparatus for regulating flow of fuel vapor between the fuel tank and the fuel vapor recovery canister, the vent apparatus including a housing coupled fluidly to the fuel tank and the fuel vapor recovery canister, a primary valve mounted in the housing and configured to block or allow a first volume of fuel vapor to flow from the fuel tank to the fuel vapor recovery canister to relieve unwanted tank pressure based on pressures applied to the primary valve, and a bleed valve mounted in the housing and configured to provide means for controlling pressures applied to the primary valve by blocking or allowing a second volume of fuel vapor, smaller than the first volume of fuel vapor, to flow from the housing to the fuel vapor recovery canister in response to an electrical input so that the electrical power required to block or allow the relatively-large first volume of fuel vapor flow controlled by the primary valve is less than that required for direct electronic control of the primary valve. 
         [0037]    Clause 2. The system of any other suitable clause, wherein the housing of the vent apparatus defines a valve compartment, the primary valve includes a deformable diaphragm that, at least in part, divides the valve compartment into a first portion and a second portion, and the bleed valve is configured to block or allow the second volume of fuel vapor to flow from the second portion of the valve compartment to the fuel vapor recovery canister in order to change the pressures applied to the primary valve. 
         [0038]    Clause 3. The system of any other suitable clause, wherein the primary valve is biased toward a closed position arranged to block the relatively-large first volume of fuel vapor from flowing by a bias spring. 
         [0039]    Clause 4. The system of any other suitable clause, wherein the bleed valve includes a stopper movable from a closed position to an opened position and an electro-magnetic actuator configured to move the stopper between the closed position and the opened position, and a return spring is arranged to bias the stopper toward the closed position. 
         [0040]    Clause 5. The system of any other suitable clause, wherein the stopper includes an armature that extends into the electro-magnetic actuator and a diaphragm that is overmolded onto a portion of the armature arranged outside the electro-magnetic actuator. 
         [0041]    Clause 6. The system of any other suitable clause, wherein the first portion of the valve compartment is coupled fluidly to the fuel tank by a tank pipe formed by the housing and the second portion of the valve compartment is coupled fluidly to the fuel tank by a valve-control pipe formed by the housing. 
         [0042]    Clause 7. The system of any other suitable clause, wherein the housing forms a canister pipe coupled fluidly to the fuel vapor recovery canister, the primary valve is configured to block or allow the relatively-large first volume of fuel vapor to flow from the valve compartment to the canister pipe, and the bleed valve is configured to block or allow the relatively-small second volume of fuel vapor to flow from the valve compartment to the canister pipe. 
         [0043]    Clause 8. The system of any other suitable clause, further comprising a valve-mover controller coupled to the bleed valve and configured to provide an electrical input to the bleed valve associated with opening of the bleed valve in response to action indicative that the user may be about to refuel the fuel tank. 
         [0044]    Clause 9. The system of any other suitable clause, wherein the valve-mover controller is configured to provide an electrical input to the bleed valve associated with opening of the bleed valve in response to a user opening an outer fuel door of a vehicle associated with the system indicative that the user may be about to refuel the fuel tank. 
         [0045]    Clause 10. A tank venting system adapted for use in a vehicle, the system comprising 
         [0046]    a fuel tank configured to store liquid fuel, 
         [0047]    a fuel vapor recovery canister located outside the fuel tank, and 
         [0048]    a vent apparatus including a housing coupled fluidly to the fuel tank and the fuel vapor recovery canister, a pressure-controlled valve mounted in a valve compartment formed by the housing and configured to block or allow a first volume of fuel vapor to flow from the fuel tank to the fuel vapor recovery canister along a first flow path, and an electronically-controlled valve mounted in the housing and configured to selectively allow a second volume of fuel vapor, smaller than the first volume of fuel vapor, to flow from a portion of the valve compartment formed by the housing to the fuel vapor recovery canister along second flow path. 
         [0049]    Clause 11. The system of any other suitable clause, wherein the pressure-controlled valve includes a deformable diaphragm that, at least in part, divides the valve compartment into a first portion and a second portion, and the electronically-controlled valve is configured to block or allow the second volume of fuel vapor to flow along the second flow path from the second portion of the valve compartment to the fuel vapor recovery canister. 
         [0050]    Clause 12. The system of any other suitable clause, wherein the pressure-controlled valve is biased toward a closed position arranged to block the relatively-large first volume of fuel vapor from flowing by a bias spring. 
         [0051]    Clause 13. The system of any other suitable clause, wherein the electronically-controlled valve includes a stopper movable from a closed position to an opened position and an electro-magnetic actuator configured to move the stopper between the closed position and the opened position, and a return spring is arranged to bias the stopper toward the closed position. 
         [0052]    Clause 14. The system of any other suitable clause, wherein the stopper includes an armature that extends into the electro-magnetic actuator and a diaphragm that is overmolded onto a portion of the armature arranged outside the electro-magnetic actuator. 
         [0053]    Clause 15. The system of any other suitable clause, further comprising a valve-mover controller coupled to the electronically-controlled valve and configured to provide an electrical input to the electronically-controlled valve associated with opening of the bleed valve in response to action indicative that the user may be about to refuel the fuel tank. 
         [0054]    Clause 16. The system of any other suitable clause, wherein the valve-mover controller is configured to provide an electrical input to the bleed valve associated with opening of the bleed valve in response to a user opening an outer fuel door of a vehicle associated with the system indicative that the user may be about to refuel the fuel tank. 
         [0055]    Clause 17. A vent apparatus for regulating flow of fuel vapor between a fuel tank and a fuel vapor recovery canister in a vehicle, the apparatus comprising 
         [0056]    a housing that forms a tank passageway configured to be coupled fluidly to the fuel tank, a canister passageway configured to be coupled fluidly to the fuel vapor recovery canister, and a valve compartment in fluid communication with the tank passageway and the canister passageway, 
         [0057]    a pressure-controlled valve mounted in the valve compartment and movable from a normally closed position to an opened position to selectively allow a first volume of fuel vapor to flow from the tank passageway to the canister passageway along a first flow path based on pressures applied to the pressure-controlled valve, and 
         [0058]    an electronically-controlled valve mounted in the housing and configured to move from a normally closed position to an opened position to selectively allow a second volume of fuel vapor, smaller than the first volume of fuel vapor, to flow from a portion of the valve compartment formed by the housing to the fuel canister passageway along second flow path in response to an electrical input so that pressures applied to the pressure-controlled valve are modified in order to cause the pressure-controlled valve to move to the opened position. 
         [0059]    Clause 18. The apparatus or system of any other suitable clause, wherein the housing forms a bypass passageway that fluidly interconnects the valve compartment with the canister passageway and that is selectively blocked by the electronically-controlled valve. 
         [0060]    Clause 19. The apparatus or system of any other suitable clause, wherein the pressure-controlled valve includes a deformable diaphragm that, at least in part, divides the valve compartment into a first portion and a second portion, and the electronically-controlled valve is configured to block or allow the second volume of fuel vapor to flow along the second flow path from the second portion of the valve compartment to the fuel vapor recovery canister. 
         [0061]    Clause 20. The apparatus or system of any other suitable clause, wherein the housing forms a valve pressurization passageway, spaced apart from the tank passageway, that opens into the second portion of the valve compartment and is configured to be coupled fluidly to the fuel tank, and the housing forms a bypass passageway that fluidly interconnects the second portion of the valve compartment with the canister passageway.