TECHNICAL FIELD

[0001] The invention generally relates to a grade vent valve assembly, sometimes referred to as a roll-over vent valve assembly.

BACKGROUND

[0002] Vehicular fuel systems include a fuel tank having a grade vent valve assembly. The grade vent vale assembly opens fluid communication between the fuel tank and other components of the fuel system to allow pressurized fuel vapor to escape the fuel tank under normal conditions, and closes fluid communication between the fuel tank and the other components of the fuel system to prevent liquid fuel from flowing out of the fuel tank when the vehicle is at an extreme angle or in an inverted position, i.e. , in a rolled-over position.

SUMMARY

[0003] A grade vent valve assembly for a fuel tank of a vehicle is provided.

The grade vent valve assembly includes a housing. The housing defines a float chamber, an inlet open to the float chamber, a liquid sealing chamber in fluid communication with the float chamber, and an orifice open to the liquid sealing chamber. A float is disposed within the float chamber. The float is moveable between a lowered position and a raised position. The grade vent valve assembly further includes a lever. The lever includes a first end that is coupled to the float. The lever extends from the first end across the orifice to a second end. The lever pivots about a fulcrum between an open position and a sealing position. When in the open position, the lever allows fluid communication between the orifice and the inlet. When in the sealing position, the lever blocks fluid communication between the orifice and the inlet. The lever moves between the open position and the sealing position in response to movement of the float between the lowered position and the raised position. The lever is disposed in the sealing position when the float is disposed in the raised position, and is disposed in the open position when the float is disposed in the lowered position.

[0004] A roll-over vent valve assembly for a fuel tank of a vehicle is also provided. The roll-over vent valve assembly includes a housing. The housing defines a float chamber, an inlet open to the float chamber, a liquid sealing chamber in fluid communication with the float chamber, and an orifice open to the liquid sealing chamber. A float is disposed within the float chamber. The float is moveable between a lowered position and a raised position. A biasing device is disposed within the float chamber between the housing and the float. The biasing device is configured for biasing the float into the raised position. The roll-over vent valve assembly further includes a lever. The lever includes a first end pivotably coupled to the float. The lever extends from the first end across the orifice to a second end. The lever pivots about a fulcrum between an open position and a sealing position. When in the open position, the lever allows fluid communication between the orifice and the inlet. When in the sealing position, the lever blocks fluid communication between the orifice and the inlet. The lever moves between the open position and the sealing position in response to movement of the float between the lowered position and the raised position. The lever is disposed in the sealing position when the float is disposed in the raised position, and is disposed in the open position when the float is disposed in the lowered position. A sealing member is attached to the lever adjacent the second end of the lever. The sealing member is moveable with the lever. The sealing member includes a synthetic rubber material and is configured for sealing against an interior surface of the liquid sealing chamber to seal the orifice. A locating mechanism interconnects the sealing member and the housing. The locating mechanism is configured for positioning the sealing member relative to the orifice. A cover is attached to and in sealing

engagement with the housing. The cover further defines the float chamber and the liquid sealing chamber.

[0005] Accordingly, the leverage created by rotating the lever about the fulcrum, which is disposed between the first end of the lever and the second end of the lever, increases the force applied to break the seal between the sealing member and the interior surface of the liquid sealing chamber, thereby improving the re-opening characteristics of the vent valve assembly.

[0006] The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic exploded view of a grade vent valve assembly.

[0008] Figure 2 is a schematic cross sectional view of the grade vent valve assembly showing a float in a lowered position and a lever in an open position.

[0009] Figure 3 is a schematic cross sectional view of the grade vent valve assembly showing the float in a raised position and the lever in a sealing position.

[0010] Figure 4 is a schematic cross sectional view of the grade vent valve assembly showing a pressure relief mechanism.

[0011] Figure 5 is a schematic perspective view of the grade vent valve assembly.

DETAILED DESCRIPTION

[0012] Those having ordinary skill in the art will recognize that terms such as

"ab ove," "b elow," "u pward, " "do wnward," "top , " "bot tom, " etc. , are used descriptively for the figures, and do not represent limitations on the scope of the invention, as defined by the appended claims.

[0013] Referring to the Figures, wherein like numerals indicate like parts throughout the several views, a grade vent valve assembly is generally shown at 20. The grade vent valve assembly 20 may also be referred to as a roll-over vent valve assembly 20. The grade vent valve assembly 20 is positioned at a top wall 22 of a fuel tank 24 of a vehicle. The grade vent valve assembly 20 includes a pressure relief mechanism 26, described in greater detail below, which allows fuel vapors to escape from the fuel tank 24 during normal operating condition. When the fuel tank 24 is oriented at an extreme angle or upside down, such as in the event of a vehicular rollover, the grade vent valve assembly 20 is configured to block fluid flow from the tank, thereby preventing fuel leakage from the tank.

[0014] Referring to Figures 1 through 3, the grade vent valve assembly 20 includes a housing 28. The housing 28 may include and be formed from, but is not limited to an acetal material, or some other similar material. The housing 28 defines a float chamber 30, and an inlet 32 open to the float chamber 30. The inlet 32 is disposed within the fuel tank 24 adjacent the top wall 22 of the fuel tank 24 such that fuel vapors that rise to the top of the fuel tank 24 may flow through the inlet 32 of the housing 28 and into the float chamber 30. The housing 28 further defines a liquid sealing chamber 34, and an orifice 36 open to the liquid sealing chamber 34. The orifice is shown in the Figures having a circular shape. However, it should be appreciated that the orifice 36 may include any suitable shape. The liquid sealing chamber 34 is in fluid communication with the float chamber 30. Accordingly, fuel vapors passing through the inlet 32 of the housing 28, may pass through the float chamber 30, around a float 42 and into the liquid sealing chamber 34, and exit the liquid sealing chamber 34 through the orifice 36. The orifice 36 is in fluid communication with the pressure relief mechanism 26. Under normal operating conditions, the vapors passing through the orifice 36 exit the grade vent valve assembly 20 through the pressure relief mechanism 26 when the fuel vapors reach a pre-determined pressure.

[0015] The grade vent valve assembly 20 includes a cover 38. The cover 38 is attached to and in sealing engagement with the housing 28. The cover 38 may be attached to the housing 28 in any suitable manner, including but not limited to attaching the cover 38 to the housing 28 with detents 40 and/or fasteners. The cover 38 may include and be manufactured from, but is not limited to, HDPE or some other similar material. The cover 38 cooperates with the housing 28 to further defining the float chamber 30 and the liquid sealing chamber 34. More specifically, the cover 38 defines the top surface and/or region of the float chamber 30 and the liquid sealing chamber 34.

[0016] The float 42 is disposed within the float chamber 30. The float 42 may include and be formed from, but is not limited to an acetal material, or some other similar material. The float 42 is moveable between a lowered position, shown in Figure 2, and a raised position, shown in Figure 3. Under normal operating conditions, the float 42 remains in the lowered position. However, if the vehicle is disposed at an extreme angle, causing liquid fuel to enter the inlet 32, then the buoyancy of the float 42 caused by any liquid fluid within the float chamber 30 causes the float 42 to rise to the raised position.

[0017] A biasing device 44 is disposed within the float chamber 30. The biasing device 44 is disposed between the housing 28 and the float 42. More specifically, the biasing device 44 is disposed between a bottom wall 46 of the float chamber 30 and the float 42. The biasing device 44 is configured to bias the float 42 into the raised position. Accordingly, the biasing device 44 provides a biasing force acting to move the float 42 from the lowered position into the raised position. While the biasing force is not great enough to move the float 42 alone, the biasing device 44 cooperates with the buoyancy force generated by any liquid entering the float chamber 30 to move the float 42 into the raised position. Preferably, the biasing device 44 includes a coil spring manufactured from stainless steel. However, the biasing device 44 may include a device other than the coils spring shown, and may be manufactured from some other material.

[0018] A lever 48 is disposed within the housing 28, and spans across the float chamber 30 and the liquid sealing chamber 34. The lever 48 includes an elongated planar substrate, and may include and be manufactured from, but is not limited to an acetal material, or some other similar material. A pivotable connection 50

interconnects the lever 48 and the housing 28. The pivotable connection 50 may be formed in any suitable manner capable of connecting the lever 48 to the housing 28 and cause the lever 48 to rotate about a rotation axis 52. As shown, the lever 48 includes two perpendicularly extending pins 54 that are rotatably supported by a pair of supports 56 disposed on opposite longitudinal sides of the lever 48. The interaction between the pins 54 and the supports 56 define the pivotable connection 50. The pivotable connection 50 may be positioned relative to the lever 48 other than shown and described herein, i.e. , below or level with the lever 48. The pivotable connection 50 defines a fulcrum about which the lever 48 rotates. Accordingly, the fulcrum defines the rotation axis 52.

[0019] The lever 48 includes a first end 58 that is pivotably coupled to the float

42. The first end 58 of the float 42 moves vertically with the float 42 as the float 42 moves between the lowered position and the raised position. The first end 58 of the lever 48 may be pivotably coupled to the float 42 in any manner capable of allowing rotation of the lever 48 about the rotation axis 52, while securing the first end 58 of the lever 48 relative to the float 42 for vertical movement therewith.

[0020] The lever 48 extends from the first end 58 to a second end 60 disposed across the orifice 36 from the first end 58. The lever 48 pivots or rotates about the fulcrum, which is disposed between the first end 58 of the lever 48 and the second end 60 of the lever 48. The lever 48 pivots between an open position, shown in Figure 2, and a sealing position, shown in Figure 3. When in the open position, the lever 48 allows fluid communication between the orifice 36 and the inlet 32, thereby allowing vapors to flow from the fuel tank 24 to the pressure relief mechanism 26. When in the sealing position, the lever 48 blocks fluid communication between the orifice 36 and the inlet 32. The lever 48 pivots between the open position and the sealing position in response to the movement of the float 42 between the lowered position and the raised position. The lever 48 is disposed in the sealing position when the float 42 is disposed in the raised position, and the lever 48 is disposed in the open position when the float 42 is disposed in the lowered position.

[0021] The first end 58 of the lever 48 is coupled to the float 42 at a first force application location 62. A center of the orifice 36 is positioned relative to the lever 48 at a second force application location 64. The lever 48 defines a length 66 between the first force application location 62 and the second force application location 64. The fulcrum is disposed a first distance 68 from the first force application location 62 and a second distance 70 from the second force application location 64. The first distance 68 is preferably at least equal to or greater than ten percent (10%) of the length 66 of the lever 48, and the second distance 70 is preferably also at least equal to or greater than ten percent (10%) of the length 66 of the lever 48. Preferably, the fulcrum is disposed at an approximate midsection of the lever 48, with the first distance 68 approximately equal to the second distance 70.

[0022] A sealing member 72 may be attached to the lever 48 adjacent the second end 60 of the lever 48. The sealing member 72 may be moveable with the lever 48. As shown, the sealing member 72 is configured for sealing against an interior surface 74 of the liquid sealing chamber 34 about a periphery of the orifice 36 to seal the orifice 36. The sealing member 72 is brought into contact with the interior surface 74 when the lever 48 is moved into the sealing position. Accordingly, liquid entering the float chamber 30, which is shown in Figure 3, moves the float 42 from the lowered position into the raised position, thereby moving the lever 48 from the open position into the sealing position. As the liquid drains from the float chamber 30, such as shown in Figure 2, the float 42 returns back to the lowered position, thereby moving the lever 48 back to the open position and breaking the seal between the sealing member 72 and the interior surface 74 of the liquid sealing chamber 34, thereby allowing vapors to flow to the pressure relief mechanism 26 again.

[0023] As shown, the sealing member 72 includes a ribbon 76 disposed between the lever 48 and the interior surface 74 of the liquid sealing chamber 34. Referring to Figure 4, the ribbon 76 includes a width 78 that is greater than a width 80 of the orifice 36. Alternatively, the sealing member 72 may be secured about a periphery of the orifice 36, with the lever 48 moving into sealing engagement with the sealing member 72 when the lever moves into the closed position. The sealing member 72 may include and be manufactured from, but is not limited to a pliable material. The pliable material may include but is not limited to a synthetic rubber material, such as viton.

[0024] Referring to Figures 1 and 5, a locating mechanism 82 interconnects the sealing member 72 and the housing 28. The locating mechanism 82 is configured to position the sealing member 72 relative to the orifice 36. As shown, the locating mechanism 82 includes a pair of posts 84 extending upward from the interior surface 74 of the liquid sealing chamber 34, that extend through a pair of cutouts 86 in the sealing member 72 to align the sealing member 72. When disposed between the lever 48 and the interior surface 74 of the liquid sealing chamber 34, with the posts 84 extending through the cutouts 86 of the sealing member 72, the sealing member 72 is positionally located relative to the lever 48. The sealing member 72 is further attached to the second end 60 of the lever 48 so as to move with the second end 60 of the lever 48. It should be appreciated that the sealing member 72 may be shaped, sized and/or configured in some other manner than shown and described herein that is capable of moving with the lever 48 to seal the orifice 36 when the lever 48 is in the sealing position.

[0025] Referring to Figures 1 and 4, the housing 28 and the cover 38 further cooperate to define a pressure chamber 88. The pressure chamber 88 is in fluid communication with the orifice 36 to receive vapor therefrom. The pressure relief mechanism 26 is disposed within the pressure chamber 88 in fluid communication with the orifice 36. As noted above, the pressure relief mechanism 26 is configured for venting pressurized vapors therethrough. As best shown in Figure 4, the pressure relief mechanism 26 includes a stainless steel ball 90 seated on a concave opening 92 defined by the housing 28. The concave opening 92 is in fluid communication with the orifice 36. When the pressure of the vapor reaches the pre-defined pressure, the vapor pressure lifts the ball vertically upward, thereby allowing the vapors to pass around an outer periphery of the ball and exit the grade vent valve assembly 20. As shown in Figure 4, when the vapor pressure is below the pre-defined pressure, the weight of the stainless steel ball 90 positions the stainless seal ball on the concave opening 92 to seal the concave opening 92 and block fluid and/or vapor flow through the concave opening 92. It should be appreciated that the pressure relief mechanism 26 may be configured and operate in some other manner not shown or described herein.

[0026] While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.