WO2022223150A1

WO2022223150A1 - Fuel tank vent valve assembly and cap assembly for same

Info

Publication number: WO2022223150A1
Application number: PCT/EP2022/025158
Authority: WO
Inventors: Markus Fritz; Stephen HOLMQUEST; Mustafa HUSEYIN; Anuj KANKARIA; Ladislav MAZIK; Vaughn Kevin Mills; Sreenivas PAI; Mayur Sudhir Pote
Original assignee: Eaton Intelligent Power Limited
Priority date: 2021-04-19
Filing date: 2022-04-19
Publication date: 2022-10-27
Also published as: EP4326574A1

Abstract

A cap assembly is provided for a valve housing of a fuel tank vent valve assembly. The cap assembly includes a top cap engageable with an upper extent of the valve housing. The cap assembly further includes an outlet cap snapped to the top cap. The top cap has an axial opening in communication with an interior of the valve housing. The cap assembly has circuitous flowpath in communication with the axial opening of the top cap to vent vapor from the vent valve assembly. For example, the fuel tank vent valve assembly may be for a diesel fuel tank, with vapor vented through the cap assembly to atmosphere.

Description

FUEL TANK VENT VALVE ASSEMBLY AND CAP ASSEMBLY FOR

SAME

TECHNICAL FIELD

[0001] The present teachings generally include a fuel tank vent valve assembly having a cap assembly configured to impede the flow of fluids out of the tank and prevent dust, debrit and insects from entering the tank.

BACKGROUND

[0002] A fuel tank may include a valve that functions to vent a vapor space in a fuel tank to limit pressure or vacuum developing in the fuel tank, such as during filling and emptying of the fuel tank.

SUMMARY

[0003] The present teachings generally provide a cap assembly for a fuel tank vent valve assembly and a fuel tank vent valve assembly that includes the cap assembly.

[0004] A cap assembly is provided for a valve housing of a fuel tank vent valve assembly. The cap assembly includes a top cap engageable with an upper extent of the valve housing. The cap assembly further includes an outlet cap snapped to the top cap. The top cap has an axial opening in communication with an interior of the valve housing. The cap assembly may have a labyrinth that defines at least two circuitous flowpaths in communication with the axial opening of the top cap to vent vapor from the vent valve assembly. The labyrinth may reduce the momentum of fluid or vapor exiting the valve housing. The circuitous flowpaths prevent or inhibit the ingress of water, dirt, dust, debris, insects, etc. For example, the fuel tank vent valve assembly may be for a diesel fuel tank, with air and fuel vapor in the vapor space vented through the cap assembly to atmosphere. [0005] The cap assembly may include other features that enable the cap assembly to accurately fit to a test apparatus such as during vent testing and for ease in gripping the cap assembly such as during manufacturing. For example, the top cap and the outlet cap may have angled exterior surfaces that help to ensure proper positioning of the top cap to the test apparatus. Pockets in an exterior of the top cap may enable increased grip of the top cap when welding the cap assembly directly or indirectly to the fuel tank. Additionally, an exterior surface of the top cap may include an integral, circumferential ring extending radially outward and configured to seal to the test apparatus and/or to the fuel tank.

[0006] A vent valve assembly for a fuel tank comprises a valve housing, a float assembly and a cap assembly. The valve housing comprises a wall defining an interior cavity, a vapor inlet, an interior wall defining a central opening of the valve housing, a valve seat defining a vent opening, and a flange defining an upper extent of the valve housing. The float assembly is disposed within the interior cavity of the valve housing and comprises a float and a seal coupled to the float. The float assembly is supported within the valve housing in a first position in which the float assembly is spaced apart from the valve seat, permitting vapor flow from the vapor inlet through the vent opening. The float assembly is moveable along a longitudinal axis of the vent valve assembly to a second position when buoyed by liquid fuel, wherein the float assembly contacts the valve seat and closes the vent opening in the second position. The cap assembly is secured to the valve housing and comprises a top cap and an outlet cap. The top cap is engaged with the flange of the valve housing and comprises a radially inward-extending wall with an axial opening in communication with the vent opening of the valve seat, an array of fingers forming an exterior surface, an upwardly- extending wall radially inward of the array of fingers, wherein the upwardly-extending wall and the array of fingers form an upwardly-opening recess and an array of openings, wherein each opening is between adjacent fingers of the array of fingers. The outlet cap is coupled to the top cap and comprises a plurality of C-baffles and one or more of a center cylindrical baffle, a plurality of star baffles and an outer baffle. Each C-baffle is positioned at a radius of the outlet cap and has an arclength of at least 50% of a circumference at the radius; and The top cap has an axial opening in communication with the vent opening of the valve seat and the cap assembly defines at least two circuitous flowpaths in communication with the axial opening of the top cap to vent vapor from the vent valve assembly when the float assembly is in the first position.

[0007] The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the present teachings when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The drawings described herein are for illustrative purposes only, are schematic in nature, and are intended to be exemplary rather than to limit the scope of the disclosure. [0009] FIG. 1 is an exploded view of a fuel tank vent valve assembly.

[0010] FIG. 2 is a side view of the fuel tank vent valve assembly.

[0011] FIG. 3 is a cross-sectional view of the fuel tank vent valve assembly taken at lines

3-3 in FIG. 2.

[0012] FIG. 4 is a perspective exploded view of a cap assembly included in the fuel tank vent valve assembly, including a top cap and an outlet cap.

[0013] FIG. 5 is another perspective exploded view of the cap assembly.

[0014] FIG. 6 is a close-up fragmentary cross-sectional view of a portion of the valve assembly shown in FIG. 2.

[0015] FIG. 7 is a plan view of the cap assembly with the outlet cap snapped to the top cap.

[0016] FIG. 8 is a cross-sectional view of the cap assembly of FIG. 7 taken at lines 8-8 in FIG. 7.

[0017] FIG. 9 is a close-up fragmentary cross-sectional view of a portion of the cap assembly with an example configuration of a pocket.

[0018] FIG. 10 is a close-up fragmentary cross sectional view of the top cap with an example configuration of a pocket.

[0019] FIG. 11 is a close-up fragmentary side view of the top cap with an example configuration of pockets.

[0020] FIG. 12 is a close-up fragmentary perspective view of a portion of the cap assembly with an example configuration of pockets.

[0021] FIGS. 13A and 13B depict cross-section and bottom views, respectively, of an outlet cap with one embodiment of a labyrinth.

[0022] FIGS. 14A and 14B depict cross-section and bottom views, respectively, of an outlet cap with one embodiment of a labyrinth.

[0023] FIGS. 15A and 15B depict cross-section and bottom views, respectively, of an outlet cap with one embodiment of a labyrinth.

[0024] FIGS. 16A and 16B depict cross-section and bottom views, respectively, of an outlet cap with one embodiment of a labyrinth.

[0025] FIGS. 17A and 17B depict cross-section and bottom views, respectively, of an outlet cap with one embodiment of a labyrinth.

[0026] FIGS. 18A and 18B depict cross-section and bottom views, respectively, of an outlet cap and a top cap with one embodiment of a labyrinth. DESCRIPTION

[0027] Referring to the drawings, wherein like reference numbers refer to like components, a valve assembly 10 may be utilized with a tank, such as a fuel tank of a vehicle. For purposes of discussion only, the fuel tank 12 is indicated in FIG. 3 in phantom to delineate areas internal to the fuel tank 12, such as a vapor space 14, and areas external to the fuel tank 12, such as the atmosphere 16. Fuel, such as diesel fuel, may be stored in the fuel tank 12. The vent valve assembly 10 is directly or indirectly coupled to the fuel tank 12. Generally, the vent valve assembly 10 may allow vapor to be vented out of the fuel tank 12. The vent valve assembly 10 may also allow air to be drawn into the fuel tank 12 to prevent an excessive vacuum in the fuel tank 12. Additionally, the vent valve assembly 10 may function as a rollover valve and/or limit fuel fill during filling of the fuel tank 12.

[0028] Referring to FIGS. 1-3, the vent valve assembly 10 includes a housing 18. The vent valve assembly 10 defines an inlet 20 in communication with vapor and/or liquid in the fuel tank 12. For example, the inlet 20 may be configured as windows 20 extending through a wall 22 of the valve housing 18 into an interior cavity 24 of the valve housing 18.

[0029] The vent valve assembly 10 includes a cap assembly 30 secured to the valve housing 18 and defining a plurality of circuitous flowpaths described herein that serve as an outlet of the vent valve assembly 10 through which vapor is vented to the exterior of the fuel tank 12, which may be the atmosphere 16, and through which air may be drawn into the fuel tank 12 through the vent valve assembly 10.

[0030] The valve housing 18 contains various valve components to vent the fuel tank 12, prevent excessive vacuum in the fuel tank 12, limit a fill level of liquid fuel in the fuel tank 12, and may also prevent liquid fuel from escaping from the fuel tank 12 through the vent valve assembly 10 when the vent valve assembly 10 is inverted relative to its position in FIG. 3 (e.g., during a vehicle rollover situation).

[0031] For example, a retainer 32 closes a bottom end 34 of the valve housing 18. A float assembly 35 is supported on the retainer 32 and is biased to the first (down) position shown due to the weight of the float assembly 35. The outer wall 22 of the valve housing 18 is the only wall of the valve housing 18 disposed radially outward of the float assembly 35. The valve housing 18 may be referred to as a single wall valve housing 18. The float assembly 35 includes a float 36 that buoyantly floats when liquid fuel enters the interior cavity 24 or enters a central void 37 at the bottom of the float 36. Vent openings 40 extend through the outer wall of the float 36. A biasing member 42 such as a spring biases the float 36 toward a valve seat 44 and also assists in maintaining the float 36 at the valve seat 44 should the vent valve assembly 10 be inverted, such as in a rollover situation. The valve seat 44 fits to an interior wall 45 of the valve housing 18 that defines a central opening 47 of the valve housing 18 shown in FIG. 3.

[0032] When the float assembly 35 is in the first position shown in FIG. 3, an opening 46 in the valve seat 44 (also referred to as a vent opening) enables vapor flow from a vapor space 14 (the space above the liquid fuel level) in the interior of the fuel tank 12 through the valve housing 18 to the cap assembly 30 and from there to atmosphere 16. A seal 50 is coupled to the float 36 and is configured to seal to the valve seat 44 when the float 36 rises sufficiently with fuel level in the fuel tank 12, such as when fuel is added or when movement of the tank 12 causes irregular movement of the fuel (often referred to as sloshing). The seal 50 and float 36 may together be referred to as the float assembly 35. Contacting the seal 50 against the valve seat 44 prevents liquid fuel from exiting through the vent valve assembly 10 and increases pressure to cause fill nozzle shutoff. For example, when liquid fuel level in the fuel tank 12 is at a predetermined level, the float 36 rises along a longitudinal axis L of the vent valve assembly 10 to a second position shown partially in phantom as 36A so that the seal 50 blocks the opening 46. The second position 36A may be referred to as a shutoff position. Because vapor and air are not vented through the vent valve assembly 10, liquid fuel level within the fuel tank 12 can no longer rise and liquid fuel backs up within a fuel pipe to shut off a dispensing nozzle (not shown). In some embodiments, the vent valve assembly 10 may include pressure relief features, such as a peel-away device, a separate pressure relief valve may be used, or the like, to further limit pressure with the float 36 in the second position 36 A.

[0033] Referring to FIGS. 1-3, the cap assembly 30 includes a top cap 60 and an outlet cap 62 snapped to the top cap 60. The outlet cap 62 may also be referred to as a spider cap. The top cap 60 is engaged with an upper extent 64 of the valve housing 18. More specifically, the upper extent 64 of the valve housing 18 includes a radially-extending flange 66 that nests in a recess 68 at a lower side of the top cap 60. A lip 70 of the top cap 60 fits under the flange 66. Additionally, axially-downward extending and generally circular rims 72 of the top cap 60 fit to axially-upwardly extending and generally circular rims 74 of the valve housing 18, as best shown in FIG. 3.

[0034] The top cap 60 has an axial opening 80 in communication with the vent opening 46 of the valve seat 44 and thereby in communication with the interior cavity 24 of the valve housing 18. Arrows A in FIG. 8 indicate vapor flow through the axial opening 80. As best indicated in FIGS. 7 and 8, the cap assembly 30 has a plurality of circuitous flowpaths PI in communication with the axial opening 80 of the top cap 60 to vent vapor from the vent valve assembly 10 when the float assembly 35 is in the first position of FIG. 3. Arrows A are the beginning of the vapor flowpaths PI through the cap assembly and are considered part of the circuitous flowpaths.

[0035] The interfitting structure of the outlet cap 62 and the top cap 60 enables the outlet cap 62 to snap fit to the top cap 60 and together create the circuitous flowpaths PI . The circuitous flowpaths PI may also be referred to as tortuous, zig-zag, or labyrinth paths and involve not only the axial component at arrows A, but also radially outward and additional axially upward and axially downward components. By providing the circuitous flowpaths PI for venting the fuel tank 12, ingress of water, water vapor, insects, dust and other debris into the interior cavity 24 of the vent valve assembly 10 is minimized or avoided as any ingress into the vent valve assembly 10 must also follow the circuitous flowpaths PI in reverse (e.g., from the atmosphere 16 to the interior cavity 24.

[0036] More specifically, as best shown in FIG. 4, the top cap 60 has an upwardly- extending wall 82. The upwardly-extending wall 82 is circular and extends axially upward along the longitudinal axis L of the vent valve assembly 10. The top cap 60 further includes upwardly-extending fingers 84 positioned radially outward of the upwardly -extending wall 82 to define an upwardly-opening recess 86 disposed between the upwardly-extending wall 82 and the upwardly-extending fingers 84. The upwardly-extending fingers 84 are spaced apart from one another so that the top cap 60 defines windows 88 (also referred to as gaps) between adjacent fingers 84. Each upwardly-extending finger 84 has a tab 90 that extends at least partially radially inward toward the upwardly-extending wall 82 in the upwardly- opening recess 86. Some of the tabs 90 are visible in FIGS. 4 and 6, for example.

[0037] The outlet cap 62 has an upper flange 92 and a lower flange 94. Both flanges 92 and 94 are shown as uninterrupted, circumferential flanges that extending radially outward in a direction toward an outer perimeter of the outlet cap 62 as shown at outer perimeter 96. In some embodiments, one or more of upper flange 92 and lower flange 94 may have a discontinuous perimeter. The upper flange 92 extends further radially outward than the lower flange 94 and establishes the outer perimeter 96 of the outlet cap 62. The upper flange 92 and the lower flange 94 are spaced apart from one another along the longitudinal axis L of the vent valve assembly 10. Stated differently, the upper flange 92 is slightly above the lower flange 94, the flanges 92, 94 thereby defining a perimeter groove 100 at the outer perimeter 96 between the flanges 92, 94. [0038] As best shown in FIGS. 6 and 8, the lower flange 94 of the outlet cap 62 fits into the upwardly-opening recess 86 of the top cap 60 with the upwardly-extending fingers 84 within the perimeter groove 100 to secure the outlet cap 62 to the top cap 60. The outlet cap 62 snaps to the top cap 60 by the fingers 84 resiliently flexing outward to slip over the lower flange 94 when the outlet cap 62 is moved along the longitudinal axis of the vent valve assembly 10 toward the top cap 60. The fingers 84 then snap back to the positions to which they are biased once the lower flange 94 passes the tabs 90. The upper flange 92 of the outlet cap 62 rests on a relatively flat surface of an upper extent 97 of the upwardly-extending fingers 84 of the top cap 60. Referring to FIGS. 4 and 5, a depression 102 is shown in the upper surface of the outlet cap 62. The depression 102 is not a through hole (e.g., it does not extend from the underside 110 of the outlet cap 62 to the upper extent 122), however, and no venting occurs at the depression.

[0039] As shown in FIGS. 5, 6, and 8, embodiments of outlet cap 62 may have a downwardly-extending inner wall 104 radially inward of the flanges 92, 94. The outlet cap 62 may also include downwardly-extending stopper tabs 106 extending downwardly from a lower edge 112 of the inner wall 104. The inner wall 104 and the lower flange 94 define a downward-opening groove 108 at an underside 110 of the outlet cap 62. The upwardly- extending wall 82 of the top cap 60 extends into the downward-opening groove 108 of the outlet cap 62. Additionally, the downwardly-extending stopper tabs 106 abut a radially inward-extending wall 111 of the top cap 60 inward of the upwardly-extending wall 82 of the top cap 60. The stopper tabs 106 axially space the lower edge 112 of the inner wall 104 of the outlet cap 62 from the radially inward-extending wall 111 of the top cap 60. As can be seen in FIGS. 7 and 8, the flowpath PI extends under the lower edge 112 and over a top edge 113 of the upwardly-extending wall 82 into upwardly-opening recess 86 and then out through the windows 88. The vapor will encounter less restriction at the windows 88, so any vapor first entering the recess 86 directly inward of a finger 84 will move circumferentially around the upwardly-opening recess 86 along the inner sides of the finger 84 once over the wall 82, and will exit out of the closest window 88 to the atmosphere 16 along the end of the flowpath P I .

[0040] Referring to FIG. 6, an exterior surface 120 of the upper flange 92 is angled radially inwardly and upwardly in a direction from an outer perimeter toward an upper extent 122 of the outlet cap 62. Stated differently, the exterior surface 120 of the upper flange 92 angles radially outwardly and downwardly in a direction from the upper extent 122 of the outlet cap 62 toward an outer perimeter of the outlet cap 62. The angled exterior surface 120 may also be referred to as a bevel or a beveled surface. The lower flange 94 angles generally outwardly and downwardly in a direction from the underside 110 of the outlet cap 62 of the outlet cap 62 generally parallel with the upper flange 92 to define the perimeter groove 100. [0041] Similarly, an exterior surface 130 of the top cap 60 (also referred to as a bevel or a beveled surface) angles radially inwardly and upwardly in a direction from exterior side surface 152 of the top cap 60 toward the upper extent 97 of the top cap 60 (e.g., the upper extent 97 of the fingers 84). In some embodiments, the exterior surface 120 of the outlet cap 62 angles radially inwardly and upwardly at a greater angle from the longitudinal axis L than the exterior surface 130 of the top cap 60. For example, as best shown in FIGS. 6 and 8, the angle 140 of the exterior surface 120 relative to the longitudinal axis L (shown relative to a vertical axis that is parallel to longitudinal axis L) may be greater than the angle 142 of the exterior surface 130 relative to longitudinal axis L. The angled exterior surface 130 of the top cap 60 and the angled exterior surface 120 of the outlet cap 62 may help to properly guide the vent valve assembly 10 into an opening in a testing apparatus (not shown) such as a testing apparatus in which helium is supplied to the vent valve assembly 10 to check venting of the vent valve assembly 10. Proper insertion of the vent valve assembly 10 ensures integrity of the connection of the vent valve assembly 10 to the testing apparatus so that accurate test data can be obtained.

[0042] With reference to FIGS. 2, 4, 7 and 8, the top cap 60 defines pockets 160 extending radially-inward from the exterior surface 130 of the upwardly-extending fingers 84. A tool or robot may grip the top cap 60 at the pockets 160 to hold the cap assembly 30 directly or indirectly against the fuel tank 12 in order to weld the cap assembly 30 directly or indirectly to the fuel tank 12. For example, a top wall of the fuel tank 12 may have an opening that the vent valve assembly 10 extends through so that the valve housing 18 extends into the vapor space 14 and the cap assembly 30 is at least partially at the exterior (e.g., at the side of the fuel tank 12 exposed to the atmosphere 16) and welded to the surface of the fuel tank 12. Various pockets 160 are shown in FIGS. 2, 4, 7, and 8. The pockets 160 may have different geometries, spacing, and may differ in number to correspond with the tool used for gripping. For example, FIG. 9 shows one of the pockets 160 as a pocket 160A having parallel upper and lower walls 162, 164, while FIG. 10 shows one of the pockets 160 as a pocket 160B having an upper wall 163 that is nonparallel with the lower wall 162. FIG. 11 shows an option of a finger 84 having two spaced pockets 160. FIG. 12 shows an option of a finger 84 having four spaced pockets 160. [0043] Referring to one or more of FIGS. 13A-13B, 14A-14B, 15A-15B, 16A-16B, 17A- 17B and 18A-18B, embodiments may include portions of a labyrinth 200 in one or more of outlet cap 62 and top cap 60, wherein the labyrinth defines at least two flowpaths PI and P2 for vapor to exit tank 12 through vent valve assembly 10. A labyrinth 200 comprises structures configured to reduce the momentum of liquid and/or vapor exiting vent opening 46 to minimize the amount of liquid and/or vapor that can exit tank 12. A labyrinth 200 further provides protection against dust, debris and insects from entering outlet cap 62, top cap 60, vent valve housing 18 and tank 12.

[0044] Labyrinth 200 comprises structures including one or more of center cylindrical baffle 202, star baffles 204, C-baffles 206, and outer baffles 210 extending downward from an underside 110 of outlet cap 62 or upward from top cap 60.

[0045] Labyrinth 200 may include center cylindrical baffle 202 comprising a generally hollow cylindrical structure that extends from the underside 110 of outlet cap 62. The length and diameter of center cylindrical baffle 202 are configured to reduce the momentum of liquid or vapor exiting vent valve housing 18.

[0046] Labyrinth 200 may include star baffles 204 comprising a plurality of curved structures arranged at a radial distance relative to longitudinal axis L and extending from the underside 110 of outlet cap 62. In some embodiments, star baffles 204 are positioned radially outward of center cylindrical baffle 202. The length, radius of curvature and arclength of each star baffle 204 and the spacing between adjacent star baffles 204 are configured to reduce the momentum of liquid or vapor exiting vent valve housing 18. Gap 216 between a lower edge of star baffles 204 and upper extent 64 of housing 18 allows a portion of vapor to flow between star baffles 204 and upper extent 64 of housing 18 as part of flowpath PL Spacing between adjacent star baffles 204 allows a portion of vapor to flow around each star baffle 204 as part of a second flowpath P2.

[0047] Labyrinth 200 may include one or more C-baffles 206, each C-baffle 206 comprising a curved structure positioned a radial distance relative to longitudinal axis L and extending axially from the underside 110 of outlet cap 62. Each C-baffle 206 may have a curvature based on the radial position and has an arc length for overlapping at least a portion of center cylindrical baffle 202, a star baffle 204 or another C-baffle 206 located radially inward. The arc length for each C-baffle 206 may be at least 50% of a circumference at the respective radius of the C-baffle 206. Referring to FIGS. 13B and 14B, C-baffles 206-1 and 206-2 are depicted as 60% closed (indicating each C-baffle 206 has an arc length corresponding to 60% of the circumference of a respective radius. C-baffle 206-1 overlaps at least a portion of each star baffle 204 located radially inward and C-baffle 206-2 overlaps at least a portion of C-baffle 206-1. Referring to FIGS. 15A and 15B, C-baffles 206-1 and 206- 2 may have an arc length corresponding to 75% of a circumference of a respective radius to overlap at least a portion of a star baffle 204 or other C-baffle 206 located radially inward. Referring to FIGS. 16A and 16B, C-baffles 206-1 and 206-2 may have an arc length corresponding to 90% of a circumference of a respective radius to overlap at least a portion of a star baffle 204 or another C-baffle 206 located radially inward. The length, radius and arc length of each C-baffle is configured to reduce the momentum of vapor exiting the tank 12. [0048] Referring to FIGS. 17A and 17B, labyrinth 200 may be formed without center cylindrical baffle 202 or star baffles 204, wherein C-baffles 206-1, 206-2 and 206-3 may extend from the underside 110 of outlet cap 62 and at least 90% of the circumference of a respective radius, wherein C-baffles 206-2 and 206-3 overlap at least a portion of a C-baffle 206 located radially inward.

[0049] Outer baffles 210 and underside 110 of outlet cap 62 may define downward opening groove 108.

[0050] The designs of top cap 60, outlet cap 62 and labyrinth 200 provide multiple pathways for vapor to exit tank 12 through vent valve housing 10. Two pathways PI and P2 are described herein. However, airflow is not restricted to either PI or P2 such that air or vapor may separate, mix and combine at multiple points in each flowpath.

[0051] A gap 214 between a lower edge of center cylindrical baffle 202 and upper extent 64 of housing 18 allows a portion of vapor to flow between center cylindrical baffle 202 and upper extent 64 of housing 18 as part of flowpath PI. A gap 216 between a lower edge of star baffles 204 and upper extent 64 of housing 18 allows a portion of vapor to flow between star baffles 204 and upper extent 64 of housing 18 as part of flowpath PI. A gap 218 between a lower edge of C-baffles 206 and upper extent 64 of housing 18 allows a portion of vapor to flow between C-baffles 206 and upper extent 64 of housing 18 as part of flowpath PI. Gaps 214, 216 and 218 may be sized based on the size of tank 12 or the fluid contents inside tank 12. In some embodiments, gaps 214, 216 and 218 are between 0.25 mm and 3 mm. In some embodiments, gaps 214, 216 and 218 are between 0.5 mm and 5 mm.

[0052] Referring to FIGS. 13A and 13B, flowpath PI refers to a first flowpath in which air/vapor can flow up through the vent opening 46, through the central opening 47 of the valve housing 18, under the center cylinder baffle 202, under the star baffles 204, under the C-baffles 206, under outer baffle 208-1 into downward-opening groove 108, over the top of the upwardly-extending wall 82, under outer baffle 208-2, into the upwardly-opening recess 86 and out through a window 88.

[0053] Flowpath P2 refers to a second flowpath in which air/vapor can flow up through the vent opening 46, through the central opening 47 of the valve housing 18, out the top of the center cylinder baffle 202, around the star baffles 204, around the C-baffles 206, under outer baffle 208-1 into downward-opening groove 108, over the top of the upwardly- extending wall 82, under outer baffle 208-2, into the upwardly-opening recess 86 and out through a window 88.

[0054] Portions of a labyrinth may be formed on top cap 60 and outlet cap 62. Referring to FIGS. 18A and 18B, labyrinth 300 comprises center cylindrical baffle 302, C-baffles 206 and outer baffles 208 extending from underside 110 of outlet cap 62 and star baffles 304 extending upward from top cap 60.

[0055] Still referring to FIGS. 18A and 18B, outlet cap 62 may be formed with tabs 312 between outer baffles 208. When outlet cap 62 is positioned on top cap 60 with upward- extending wall 82 positioned between outer baffles 208, tabs 312 maintain a separation distance between underside 110 of outlet cap 62 and an upper extent 113 of upward- extending wall 82. Tabs 312 may be configured to provide separation distance based on one or more of a liquid or vapor present in tank 12.

[0056] While the best modes for carrying out the many aspects of the present teachings have been described in detail, those familiar with the art to which these teachings relate will recognize various alternative aspects for practicing the present teachings that are within the scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A cap assembly for a valve housing of a fuel tank vent valve assembly, the cap assembly comprising: a top cap comprising: a radially inward-extending wall with an axial opening; an array of fingers forming an exterior surface; an array of openings, wherein each opening is between adjacent fingers of the array of fingers; and an upwardly-extending wall radially inward of the array of fingers, wherein the upwardly-extending wall and the array of fingers form an upwardly-opening recess; and an outlet cap coupled to the top cap, the outlet cap comprising: a plurality of C-baffles, each C-baffle positioned at a radius of the outlet cap and having an arclength of at least 50% of a circumference at the radius; and one or more of: a center cylindrical baffle; a plurality of star baffles; and an outer baffle; wherein the cap assembly defines at least two circuitous flowpaths in communication with the axial opening of the top cap to vent vapor from the tank.

2. The cap assembly of claim 1, wherein each C-baffle has an arclength of at least 60% of the circumference at the radius.

3. The cap assembly of claim 1, wherein: the outlet cap comprises two outer baffles forming a downward-opening groove; and a tab between the two outer baffles, wherein the upwardly-extending wall of the top cap extends into the downward opening groove of the outlet cap and contacts the tab, wherein the cap assembly comprises a space between a top edge of the upwardly -extending wall of the top cap and the underside of the outlet cap.

4. The cap assembly of claim 1, wherein: the outlet cap has an inner wall with downwardly-extending stopper tabs radially inward of the upper flange and the lower flange to define a downward-opening groove at an underside of the outlet cap; and the upwardly-extending wall of the top cap extends into the downward-opening groove of the outlet cap.

5. The cap assembly of claim 3, wherein: the downwardly-extending stopper tabs abut the top cap inward of the upwardly- extending wall of the top cap to axially space a lower edge of the inner wall of the outlet cap from the top cap.

6. The cap assembly of claim 1, wherein: the top cap defines pockets recessing radially-inward from an exterior of the upwardly-extending fingers.

7. The cap assembly of claim 1, wherein the labyrinth comprises: a center cylindrical baffle; a plurality of star baffles positioned at a radius outside the center cylindrical baffle; a plurality of C-baffles positioned at radii outside the plurality of star baffles, each C- baffle having an arclength of at least 50% of the circumference at the respective radius; and a plurality of outer baffles positioned at radii outside the plurality of C-baffles.

8. The cap assembly of claim 7, wherein each of the center cylindrical baffle, the plurality of star baffles, the plurality of C-baffles and the plurality of outer baffles extend from the outlet cap.

9. The cap assembly of claim 7, wherein one or more of the center cylindrical baffle, the plurality of star baffles and the plurality of C-baffles extend from the top cap.

10. The cap assembly of claim 1, wherein each C-baffle has an arclength of at least 60% of the circumference at the respective radius.

11. A vent valve assembly for a fuel tank comprising: a valve housing comprising: a wall defining an interior cavity; a vapor inlet; an interior wall defining a central opening of the valve housing; a valve seat defining a vent opening; and a flange defining an upper extent of the valve housing; a float assembly disposed within the interior cavity of the valve housing, the float assembly comprising: a float; and a seal coupled to the float; wherein the float assembly is supported within the valve housing in a first position in which the float assembly is spaced apart from the valve seat, permitting vapor flow from the vapor inlet through the vent opening, wherein the float assembly moves along a longitudinal axis of the vent valve assembly to a second position when buoyed by liquid fuel, the float assembly contacting the valve seat and closing the vent opening in the second position; a cap assembly secured to the valve housing, wherein the cap assembly comprises: a top cap engaged with the flange of the valve housing, the top cap comprising: a radially inward-extending wall with an axial opening in communication with the vent opening of the valve seat; an array of fingers forming an exterior surface; an upwardly-extending wall radially inward of the array of fingers, wherein the upwardly-extending wall and the array of fingers form an upwardly-opening recess; an array of openings, wherein each opening is between adjacent fingers of the array of fingers; and an outlet cap coupled to the top cap, the outlet cap comprising: a plurality of C-baffles, each C-baffle positioned at a radius of the outlet cap and having an arclength of at least 50% of a circumference at the radius; and one or more of: a center cylindrical baffle; a plurality of star baffles; and an outer baffle; wherein the top cap has an axial opening in communication with the vent opening of the valve seat; and wherein the cap assembly defines at least two circuitous flowpaths in communication with the axial opening of the top cap to vent vapor from the vent valve assembly when the float assembly is in the first position.

12. The vent valve assembly of claim 11, wherein: the outlet cap has a lower flange and an upper flange both extending radially outward at an outer perimeter of the outlet cap and spaced apart from one another along the longitudinal axis of the vent valve assembly to define a perimeter groove; and the lower flange fits into the upwardly-opening recess with the upwardly-extending fingers within the perimeter groove to secure the outlet cap to the top cap.

13. The vent valve assembly of claim 12, wherein: the upper flange of the outlet cap rests on the upper extent of the upwardly-extending fingers of the top cap; and an exterior surface of the upper flange is angled radially inwardly and upwardly in a direction from the outer perimeter of the outlet cap toward an upper extent of the outlet cap.

14. The vent valve assembly of claim 12, wherein: the upper flange angles radially outwardly and downwardly in a direction from an upper extent of the outlet cap toward the outer perimeter of the outlet cap.

15. The vent valve assembly of claim 12, wherein: the lower flange angles radially outwardly and downwardly in a direction from an upper extent of the outlet cap toward the outer perimeter of the outlet cap.