Patent Publication Number: US-11644115-B2

Title: Fuel cap with duckbill valve

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation under 35 U.S.C § 120 and 37 C.F.R. § 1.53(b) of U.S. patent application Ser. No. 16/851,262 filed Apr. 17, 2020, which is a continuation of U.S. patent application Ser. No. 16/194,620 filed Nov. 19, 2018, each of which claims the benefit of U.S. Provisional Application Ser. No. 62/592,962 filed Nov. 30, 2017, and each of which is hereby incorporated by reference in its entirety. 
    
    
     FIELD 
     This disclosure relates in general to a fuel cap for an internal combustion engine, and more specifically, to apparatus and techniques for regulation of evaporative emissions using the fuel cap. 
     BACKGROUND 
     A fuel tank for an internal combustion engine encloses and stores combustible fuel. The fuel may include hydrocarbons. The fuel naturally evaporates into the atmosphere. When hydrocarbons evaporate and escape to the atmosphere, the hydrocarbons may become pollutants. Evaporation rates may be increased by heat from warm weather. Evaporation levels may accumulate over time for engines that often spend long periods of time between starts and/or spend long periods in non-climate controlled environments such as garages. Evaporation is also caused from heat from the operation of the engine. 
     A fuel cap may vent pressurized fuel vapor out of the fuel tank into one or more filters for removing hydrocarbons. High pressure in the fuel tank may affect the venting of the pressurized vapor. Challenges remain in venting of evaporative fuel vapors from the fuel tank. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments are described herein with reference to the following drawings. 
         FIG.  1    illustrates a fuel cap. 
         FIG.  2 A  illustrates an example exploded view of the fuel cap of  FIG.  1   . 
         FIG.  2 B  illustrates another example exploded view of the fuel cap of  FIG.  1   . 
         FIG.  3    illustrates a cross sectional view of the fuel cap of  FIG.  1   . 
         FIG.  4 A  illustrates a more detailed view of the fuel cap of  FIG.  1    including a duckbill valve. 
         FIG.  4 B  illustrates the duckbill valve of  FIG.  4 A . 
         FIGS.  5 A and  5 B  illustrate views of the top of the duckbill valve. 
         FIGS.  5 C and  5 D  illustrate views of the bottom of the duckbill valve. 
         FIG.  5 E  illustrates a cross sectional side view of the duckbill valve. 
         FIGS.  6 A and  6 B  illustrate views of the top of the duckbill valve with outwardly arranged bosses. 
         FIGS.  6 C and  6 D  illustrate views of the bottom of the duckbill valve with outwardly arranged bosses. 
         FIG.  6 E  illustrates a cross sectional side view of the duckbill valve with outwardly arranged bosses. 
         FIGS.  7 A and  7 B  illustrate views of the top of the duckbill valve with inwardly arranged bosses. 
         FIGS.  7 C and  7 D  illustrate views of the bottom of the duckbill valve with inwardly arranged bosses. 
         FIG.  7 E  illustrates a cross sectional side view of the duckbill valve with inwardly arranged bosses. 
         FIGS.  8 A and  8 B  illustrate views of the top of the duckbill valve with both outwardly and inwardly arranged bosses. 
         FIGS.  8 C and  8 D  illustrate views of the bottom of the duckbill valve with both outwardly and inwardly arranged bosses. 
         FIG.  8 E  illustrates a cross sectional side view of the duckbill valve with both outwardly and inwardly arranged bosses. 
         FIGS.  9 A and  9 B  illustrate views of the top of the duckbill valve with a large spacer ring. 
         FIGS.  9 C and  9 D  illustrate views of the bottom of the duckbill valve with the large spacer ring. 
         FIG.  9 E  illustrates a cross sectional side view of the duckbill valve with the large spacer ring. 
         FIGS.  10 A and  10 B  illustrate views of the top of the duckbill valve with a small spacer ring. 
         FIGS.  10 C and  10 D  illustrate views of the bottom of the duckbill valve with the small spacer ring. 
         FIG.  10 E  illustrates a cross sectional side view of the duckbill valve with the small spacer ring. 
         FIGS.  11 A and  11 B  illustrate views of the top of the duckbill valve with the large and small spacer rings. 
         FIGS.  11 C and  11 D  illustrate views of the bottom of the duckbill valve with the large and small spacer rings. 
         FIG.  11 E  illustrates a cross sectional side view of the duckbill valve with the large and small spacer rings. 
         FIG.  12    illustrates a flowchart for manufacturing the fuel cap. 
     
    
    
     DETAILED DESCRIPTION 
       FIG.  1    illustrates a fuel cap  100 , which may include at least an outer shell or cover  105 , an internal sleeve  140 , and a tether  150 . The internal sleeve  140  may couple internal components of the fuel cap  100  together. The internal sleeve  140  may include a threading or another coupling mechanism to secure the fuel cap  100  to a fuel port of an engine. The tether  150  includes an extended member, which may be formed of plastic and may be flexible or rigid, that connects the fuel cap  100  to an anchor. The anchor is sized larger than the largest dimension of the fuel port of the engine to prevent the fuel cap  100  from becoming detached from the engine at a distance greater than the length of the extended member. 
     The engine may be a small internal combustion engine applicable to chainsaws, lawn mowers, wood chippers, stump grinders, concrete trowels, mini excavators, concrete saws, portable saw mills, weed trimmers, all-terrain vehicles, wood splitters, pressure washers, garden tillers, tractors, plows, snow blowers, welding equipment, generators, and other devices. Often such small engine containing devices are used in close proximity to a user (e.g., a human). It is desirable to reduce or minimize the amount of hydrocarbon evaporative emissions from these types of devices. The fuel cap  100  includes an evaporative emission reduction device for reducing the leakage or escape of emissions from the fuel tank of the engine. 
       FIG.  2 A  illustrates an exploded view of the fuel cap  105  of  FIG.  1    including the evaporative emission reduction device. In addition to the components discussed with respect to  FIG.  1   , the fuel cap  105   a  includes an upper filter retainer  110   a , a lower filter retainer  125   a , a duck bill valve  130 , a valve support  135   a , and a seal  145   a . The upper filter retainer  110   a  and the lower filter retainer  125   a  support an upper filter  115   a  and a lower filter  120   a . Various materials such as molded plastic may be used for the internal sleeve  140   a , the tether  150   a , the upper filter retainer  110   a , the lower filter retainer  125   a , the valve support  135   a , and the seal  145   a . Additional, different, or fewer components may be included.  FIG.  2 B  illustrates an example exploded view of the fuel cap of  FIG.  1    using similar components that vary in structure from the example of  FIG.  2 A  including a fuel cap  105   b , an upper filter retainer  110   b , a lower filter retainer  125   b , a duck bill valve  130 , a valve support  135   b , an internal sleeve  140   b , and a seal  145   b . The upper filter retainer  110   b  and the lower filter retainer  125   b  support an upper filter  115   a , a middle filter  118 , and a lower filter  120   a.    
       FIG.  3    illustrates a cross sectional view of the fuel cap of  FIG.  1   . Between the upper filter  115  and the lower filter  120  may be a hydrocarbon filter  300  that removes hydrocarbon material from the vapor released from the fuel tank. The hydrocarbon filter may adsorb hydrocarbons from the vapor. The hydrocarbon filter  300  may include adsorption capsules. Vapor entering the hydrocarbon filter may be hydrocarbon evaporative emission and the flow leaving the hydrocarbon filter may be considered scrubbed vapor or air. The scrubbed air may be safe for release into the atmosphere according to one or more guidelines or regulations. The upper filter  115 , the lower filter  120 , or both may be formed from a felt or another type of fabric. Example types of fabric include a compounding non-spinning fabric. The combination of the upper filter  115  the lower filter  120  may be referred to as a dilayer compounding non-spinning fabric. In one example, three layers (e.g., upper filter  115   a , middle filter  118 , and lower filter  120   a ) form a trilayer fabric. 
       FIG.  4 A  illustrates a more detailed view of the fuel cap of  FIG.  1    including a duckbill valve  130 .  FIG.  4 B  illustrates the duckbill valve  130  of  FIG.  4 A . The duck bill valve  130  may include multiple valves. The valves may include one or more one-way valve and/or one or more check valve. The valves allow air flow or pressure to flow in one direction through the duckbill valve  130  and not in another direction through the duckbill valve  130 . 
       FIGS.  5 A and  5 B  illustrate views of the top of a duckbill valve member  530  including a major valve  533  and multiple minor valves (e.g., minor valve  531  and  532 ). The major valve  533  may allow air flow in a first direction (e.g., into the fuel tank from the atmosphere or elsewhere in the vicinity of the engine) and the minor valves  531  and  532  may allow air flow in a second direction (e.g., out of the fuel tank to the atmosphere or elsewhere in the vicinity of the engine). The valves may have any size, orientation, and direction. The terms minor and major do not necessarily represent relative size or flow volumes for the valves. 
       FIGS.  5 C and  5 D  illustrate views of the bottom of the duckbill valve member  530  and  FIG.  5 E  illustrates a cross sectional side view of the duckbill valve, illustrating that the major valve  533  extends in a duck bill shape or a triangular prism shape away from the base of the duckbill valve member  530  towards the interior of the fuel tank. The major valve  533  includes a first angled portion  538  and a second angled portion  539  that terminate at opening  535 . The minor valves  531  and  532  each include a domed shaped cavity for openings  536  and  537 , respectively, that is concave in a direction opposite that of the extension of the major valve  533 . Thus, the major valve  533  and the minor valves  531  and  532  operate as one-way or check valves in opposite directions. 
     When air or vapor pressure inside the fuel tank of the engine exceeds a threshold, a force is applied to the domed shaped cavities for openings  536  and  537 . The force causes the openings  537  and  537  to allow air or vapor flow from the fuel tank and into the fuel cap including the emission filter. When the pressure inside the fuel tank of the engine exceeds a second threshold, the force may cause the duckbill valve member  530  to deform or otherwise change shape. Some of the deformation allows the duckbill valve member  530  to operate properly. However, when the duckbill valve member  530  becomes too deformed it may contact an adjacent member (e.g., lower filter retainer  125 ). Contact with the adjacent member may disrupt the valve operation and restrict the flow of air out of the fuel tank. 
       FIG.  4 B  illustration a distance a between the adjacent member (e.g., lower filter retainer  125 ) and the duckbill valve member  530 . When the distance a falls below a spacing threshold because the duckbill valve member  530  has become too deformed, the duckbill valve member  530  does not operate properly. 
     The following embodiments include apparatus and techniques for preventing this disruption of the valve operation and/or maintaining at least the distance a between the adjacent member (e.g., lower filter retainer  125 ) and the duckbill valve member. 
       FIGS.  6 A and  6 B  illustrate views of the top of the duckbill valve member  630  with outwardly arranged bosses  690  and  691 .  FIGS.  6 C and  6 D  illustrate views of the bottom of the duckbill valve  630  with outwardly arranged bosses  690  and  691 .  FIG.  6 E  illustrates a cross sectional side view of the duckbill valve  630  with outwardly arranged bosses  690  and  691 . 
     The bosses  690  and  691  press against or near the adjacent member (e.g., lower filter retainer  125 ). The bosses  690  and  691  prevent or reduce deformation to the duckbill valve member  630 . Therefore, the duckbill valve member  630  can operate under higher pressures in the fuel tank without reduction of the flow of air through the minor valves  531  and  532 . 
     The bosses  690  and  691  may be made of the same material as the duckbill valve member  630  (e.g., rubber, elastomer, silicone or hydrocarbon-resistant fluorosilicone rubber). The bosses  690  and  691  may be positioned at a predetermined distance (e.g., 1 mm) from minor valves  531  and  532  in a direction of the circumference of the duckbill valve member  630 . The bosses  690  and  691  may be formed integrally with the duckbill valve member  630 . In one example, the bosses  690  and  691  may be dimples pressed into the duckbill valve member  630  from the opposite side. 
     Some arrangements may include different numbers of bosses (e.g., one, three, five, or another number). The bosses may be spaced at different distances from the major valve  533  or minor valves  531  and  531 . The bosses may be spaced from the circumference of the duckbill valve member  630 . The bosses may be another shape such as circular, triangular, or oval. The sides of the spacer rings may be sloped. The bosses may be arranged in a line in a direction perpendicular to a face of the bosses. Alternatively, the bosses may be arranged at different angles with respect to the major valve  533 , minor valves  531  and  531 , or the circumference of the duckbill valve member  630 . The bosses  690  and  691 , or other bosses described herein, may be sized at 1 mm cubed, 1 mm by 2 mm by 1 mm, or another size. One of the bosses may be one size and another of the bosses may be a different size. Any of these variations may be applied to bosses  690  and  691  as well as other embodiments herein. 
       FIGS.  7 A and  7 B  illustrate views of the top of the duckbill valve  730  with inwardly arranged bosses  790  and  791 .  FIGS.  7 C and  7 D  illustrate views of the bottom of the duckbill valve  730  with inwardly arranged bosses  790  and  791 .  FIG.  7 E  illustrates a cross sectional side view of the duckbill valve  730  with inwardly arranged bosses  790  and  791 . 
     The bosses  790  and  791  press against or near the adjacent member (e.g., lower filter retainer  125 ). The bosses  790  and  791  prevent or reduce deformation to the duckbill valve member  730 . Therefore, the duckbill valve member  730  can operate under higher pressures in the fuel tank without reduction of the flow of air through the minor valves  531  and  532 . 
     The bosses  790  and  791  may be made of the same material as the duckbill valve member  730  (e.g., rubber, elastomer, silicone or hydrocarbon-resistant fluorosilicone rubber). The bosses  790  and  791  may be positioned at a predetermined distance (e.g., 1 mm) from minor valves  531  and  532  in a direction toward the center of the duckbill valve member  630 . The bosses  790  and  791  may be positioned at a predetermined distance (e.g., 0.1 mm) from major valve  533  in a direction toward the circumference of the duckbill valve member  630 . Variations in shapes, sizes, quantity, and arrangement of bosses  790  and  791  may be made and examples of such variations are described in other embodiments herein. 
       FIGS.  8 A and  8 B  illustrate views of the top of the duckbill valve  830  with both outwardly arranged bosses  690  and  691  and inwardly arranged bosses  790  and  791 .  FIGS.  8 C and  8 D  illustrate views of the bottom of the duckbill valve  830  with outwardly arranged bosses  690  and  691  and inwardly arranged bosses  790  and  791 .  FIG.  8 E  illustrates a cross sectional side view of the duckbill valve  830  with both outwardly arranged bosses  690  and  691  and inwardly arranged bosses  790  and  791 . Variations in shapes, sizes, quantity, and arrangement of bosses  690 ,  691 ,  790  and  791  may be made and examples of such variations are described in other embodiments herein. 
       FIGS.  9 A and  9 B  illustrate views of the top of the duckbill valve  930  with a large spacer ring  990 .  FIGS.  9 C and  9 D  illustrate views of the bottom of the duckbill valve  930  with the large spacer ring  990 .  FIG.  9 E  illustrates a cross sectional side view of the duckbill valve  930  with the large spacer ring  990 . The large spacer ring  990  may have a diameter greater than a width of the major valve  533  and smaller than a dimeter of the duckbill valve  930 . Examples for the diameter of the large spacer ring  990  may include 10 mm and 15 mm. 
       FIGS.  10 A and  10 B  illustrate views of the top of the duckbill valve  1030  with a small spacer ring  1090 .  FIGS.  10 C and  10 D  illustrate views of the bottom of the duckbill valve  1030  with the small spacer ring  1090 .  FIG.  10 E  illustrates a cross sectional side view of the duckbill valve  1030  with the small spacer ring  1090 . The small spacer ring  1090  may have a diameter smaller than a width of the major valve  533 . The small spacer ring  1090  may have a diameter equal to or greater than a width of the minor valves  531  and  532 . Examples for the small spacer ring  1090  may include 5 mm and 8 mm. 
       FIGS.  11 A and  11 B  illustrate views of the top of the duckbill valve  1130  with the large spacer ring  990  and the small spacer ring  1090 .  FIGS.  11 C and  11 D  illustrate views of the bottom of the duckbill valve  1130  with the large spacer ring  990  and the small spacer ring  1090 .  FIG.  11 E  illustrates a cross sectional side view of the duckbill valve  1130  with the large spacer ring  990  and the small spacer ring  1090 . A ratio between the diameter of the large spacer ring  990  and the small spacer ring  1090  may be in a range from 1.5 to 3. An example ratio is 2 such that the large spacer ring  990  is twice the width of the small spacer ring  1090 . 
     Examples for the width and height (H) of the large spacer ring  990  and the small spacer ring  1090  may include 1 mm, 1.2 mm, 1.5 mm, and 2 mm. The spacer rings may have the same or different width or heights. The spacer rings may not be complete rings. In some examples, one or more of the spacer rings may be semi-circles or quarter-circles. The spacer rings may be another proportion of a complete circle such as 70% or 90%. The spacer rings may be discontinuous and formed of spaced portions (e.g., dashed circle shape). Other quantities of spacer rings may be used. The spacer rings may be concentric or arranged at different sides of the duckbill valve member. The spacer rings, rather than circular, may be square, rectangular or another shape. The sides of the spacer rings may be sloped. 
       FIG.  12    illustrates an example flowchart for manufacturing a fuel cap including a duckbill filter or valve and an evaporative emission reduction device. Additional, different, or fewer acts may be included. 
     An act S 101 , an evaporative emission reduction device is provided to a fuel cap (e.g., fuel cap  100 ). The evaporative emission reduction device may include a hydrocarbon filter that adsorbs vapor or hydrocarbon material from the vapor released from the fuel tank. The evaporative emission reduction device reduces the escape of vapors from a fuel tank. 
     At act S 103 , a deformation prevention member is mounted on a valve member. The deformation prevention member may include one component, two components, or more than two components. The deformation prevention member may include at least one dimension (e.g., height) that meets or exceeds a deformation prevention threshold distance. The deformation prevention threshold distance may be selected according to the dimensions or materials of the valve member. Stiffer (e.g., with coefficient of elasticity below a predetermined value) valve members may have lower deformation prevention thresholds and require larger height for the deformation prevention member. More flexible (e.g., with coefficient of elasticity above a predetermined value) valve members may have higher deformation prevention thresholds and require smaller height for the deformation prevention member. 
     The deformation prevention member prevents the valve from become deformed, which may affect the control of the escape of vapors from the fuel tank. The valve member may be shaped in a disc that can twist or become contorted and prevent the valve opening from opening and closing in normal operation. The deformation may be caused by pressure above a predetermined pressure threshold in the fuel tank. The pressure threshold may depend on the size of the fuel tank, the shape of the fuel tank, the type of fuel in the fuel tank, the diameter of the fuel tank opening for the fuel tank, and/or the width and materials for the valve member. The deformation prevention member may be placed at a predetermined distance from the opening of the valve to protect the shape of the valve member and ensure that the valve opening open and closes in normal operation. 
     The deformation prevention member may be placed between the valve and an outer circumference of the valve member or between the valve in and a center of the valve member. The deformation prevention member may include two components include a first ring outside of the valve in a direction of an outer circumference of the valve member and a second ring that overlaps the valve. 
     At act S 105 , the valve member is aligned to the evaporative emission reduction device with a valve retainer. The valve retainer may include multiple layers such as the upper filter retainer  110   a  and the lower filter retainer  125   a.    
     At act S 107 , the deformation prevention member, the valve retainer, and the evaporative emission reduction device are secured to the fuel cap with a retainer sleeve. The retainer sleeve may include an outer shell or cover  105 , an internal sleeve  140 , or a combination of shell  105  and internal sleeve  140 . 
     In one implementation, the fuel cap may be anchored to the fuel cap or the engine including the fuel tank with a tether (e.g., tether  150 ). The tether may be shaped so that it cannot be removed from the fuel tank through the opening for the fuel tank. In another example, the tether is a cable or other coupling device that is secured to the fuel tank or the engine by a bolt, welding, rivet, or another fastening technique. 
     The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those skilled in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Additionally, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive. 
     While this specification contains many specifics, these should not be construed as limitations on the scope of the invention or of what may be claimed, but rather as descriptions of features specific to particular embodiments of the invention. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination. 
     Similarly, while operations are depicted in the drawings and described herein in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. 
     One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the description. 
     It is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is understood that the following claims including all equivalents are intended to define the scope of the invention. The claims should not be read as limited to the described order or elements unless stated to that effect. Therefore, all embodiments that come within the scope and spirit of the following claims and equivalents thereto are claimed as the invention.