Patent Publication Number: US-6986340-B2

Title: Automatic fuel vent closure and fuel shutoff apparatus having mechanical actuation

Description:
RELATED APPLICATIONS 
   This application claims priority to U.S. Provisional Patent Application Ser. No. 60/270,666 filed Feb. 20, 2001. 

   FIELD OF THE INVENTION 
   The present invention relates to the field of internal combustion engines and, more particularly, to mechanically-actuated components in the fuel systems of internal combustion engines. 
   BACKGROUND OF THE INVENTION 
   Internal combustion engines are used in a variety of applications, such as lawn mowers, generators, pumps, snow blowers, and the like. Such engines usually have fuel tanks coupled thereto to supply fuel to the engine through a supply line. It is desirable to reduce emissions from devices powered by internal combustion engines. Even when the engine is not being used, the engine can release emissions of hydrocarbons or gasoline resulting from daily ambient temperature changes. Such emissions are known as “diurnal” emissions. 
   To help reduce emissions from the engine, it is known to provide internal combustion engines with fuel shutoff devices that block the flow of fuel to the engine upon engine ignition shutdown. Without such a shutoff device, fuel is wasted, and unburned fuel is released into the environment, thereby increasing exhaust emissions. Likewise, the presence of unburned fuel in the combustion chamber may cause dieseling. When the engine is not operating, pressure buildup in the fuel tank caused by increased ambient temperatures can force fuel into the engine, where the fuel can be released into the atmosphere. 
   It is also desirable to reduce emissions from the fuel tank. Fuel tanks are typically vented to the atmosphere to prevent pressure buildup in the tank. While the engine is operating and drawing fuel from the fuel tank, the vent in the fuel tank prevents excessive negative pressure inside the tank. While the engine is not operating (i.e., in times of non-use and storage), the vent prevents excessive positive pressure that can be caused by fuel and fuel vapor expansion inside the tank due to increased ambient temperatures. Fuel vapors are released to the atmosphere, primarily when a slight positive pressure exists in the tank. 
   One common method of venting fuel tanks includes designing a permanent vent into the fuel tank cap. Typically, the fuel tank is vented via the threads of the screw-on fuel tank cap. Even when the cap is screwed tightly on the tank, the threaded engagement does not provide an air-tight seal. Therefore, the fuel tank is permanently vented to the atmosphere. Another method of venting fuel tanks includes the use of a vent conduit that extends away from the tank to vent vapors to a portion of the engine (i.e., the intake manifold) or to the atmosphere at a location remote from the tank. 
   SUMMARY OF THE INVENTION 
   The present invention provides a fuel vent closure device that is actuated automatically by the operation of a manually-operable engine control device such as a deadman or bail lever, a start/stop device such as a button, knob, or key, or a speed control device. In other words, the engine control device, which is already coupled to the ignition circuit to selectively start and stop the engine, is also coupled to the vent closure device so that no additional action on behalf of the operator is required to actuate the vent closure device. In fact, the operator may not even know that the manual operation of the engine control device simultaneously actuates the vent closure device. 
   When the engine control device is remotely located from the engine and the fuel tank (as is the case with a deadman or bail lever on the handle of a walk behind lawn mower), the automatic actuation of the vent closure device occurs from a remote location. Linkage assemblies, which can include bowden cables, levers, cams, and other members, are used to remotely actuate the vent closure device. 
   In one aspect of the invention, the engine control device and the fuel vent closure device are also coupled to an automatic fuel shutoff device that blocks the flow of fuel to the internal combustion engine when the engine stops. Preferably, the single action of manually operating the engine control device causes actuation of each of the vent closure device, the fuel shutoff device, and the engine ignition system. Again, if the engine control device is remote from the engine and the fuel tank, linkages are used to remotely actuate the ignition switch, the vent closure device, and the fuel shutoff device. In a preferred embodiment, a single valve assembly acts as both the fuel vent closure device and the fuel shutoff device. 
   Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic view of an internal-combustion-engine-powered device having a deadman or bail lever coupled to a fuel vent closure and fuel shutoff device embodying the invention. 
       FIG. 2  is a schematic view of an internal-combustion-engine-powered device having an engine speed control device coupled to the fuel vent closure and fuel shutoff device embodying the invention. 
       FIG. 3  is a schematic view of another fuel vent closure and fuel shutoff device embodying the invention and coupled to an on/off device. 
       FIG. 4  is a schematic view of the fuel vent closure and fuel shutoff device of  FIG. 3  coupled to an on/off/start device. 
       FIGS. 5 and 6  show a fuel tank having a vent and a fuel supply port adapted to be connected to the fuel vent closure and fuel shutoff device. 
       FIG. 7  is a partial view of  FIG. 6  showing an alternative vent configuration. 
       FIGS. 8 and 9  show a mounting arrangement for the fuel vent closure and fuel shutoff device. 
       FIGS. 10 and 11  show an alternative mounting arrangement for the fuel vent closure and fuel shutoff device. 
       FIGS. 12 and 13  show a valve design that can be used for the fuel vent closure and fuel shutoff device. 
       FIGS. 14 and 15  show another valve design that can be used for the fuel vent closure and fuel shutoff device. 
       FIGS. 16 and 17  show yet another valve design that can be used for the fuel vent closure and fuel shutoff device. 
       FIGS. 18–20  show yet another valve design that can be used for the fuel vent closure and fuel shutoff device. 
       FIGS. 21–23  show yet another valve design that can be used for the fuel vent closure and fuel shutoff device. 
       FIG. 24  is a lawnmower having an internal combustion engine embodying the invention. 
       FIG. 25  is a portable generator having an internal combustion engine embodying the invention. 
       FIG. 26  is a portable pressure washer having an internal combustion engine embodying the invention. 
       FIG. 27  is an automatic backup power system having an internal combustion engine embodying the invention. 
       FIG. 28  is a multi-cylinder, V-twin internal combustion engine embodying the invention. 
       FIG. 29  is a single cylinder internal combustion engine embodying the invention. 
   

   Before one embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or being carried out in various ways. Also, it is understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  schematically illustrates a device  10  having an internal combustion engine  14 . In  FIG. 1 , the device  10  is illustrated as being a lawn mower  10   a  (see  FIG. 24 ), but could alternatively be a snow blower (not shown), a portable generator  10   b  (see  FIG. 25 ), a pump, such as the type commonly used in a portable pressure washer  10   c  (see  FIG. 26 ), a stand-alone generator, such as the type commonly used for an automatic backup power system  10   d  (see  FIG. 27 ), or the like. The engine  14  can be a multi-cylinder engine, such as a V-twin or opposed-cylinder engine  14   a  (see  FIG. 28 ), or a single-cylinder engine  14   b  (see  FIG. 29 ). 
   The lawnmower  10   a  includes an engine control device  18  coupled to the internal combustion engine  14 . The engine control device  18  is manually operable to stop operation of the engine  14  by grounding an ignition switch  22 . The engine control device  18  shown in  FIG. 1  is known as a deadman lever or a bail lever and is mounted on the lawn mower handle  26 , remote from the engine  14 , as is commonly understood. A bowden cable or other suitable actuator  30  (shown schematically) connects the engine control device  18  to a linkage assembly  34  that actuates the ignition switch  22 . Any suitable linkage assembly  34  can be used. 
   The engine control device  18  can also operate to stop the rotation of the blade (not shown). As seen in  FIG. 1 , an engine flywheel brake  38  is mounted on the linkage assembly  34 . When the deadman lever is released (as shown in phantom in  FIG. 1 ), the linkage assembly  34  is oriented such that the brake  38  engages a flywheel  42 . Stopping the rotation of the flywheel  42  stops the rotation of the blade. Other blade braking mechanisms are also known and can be used instead of the engine flywheel brake  38 . 
   The lawnmower  10   a  also includes a fuel tank  46  coupled to the engine  14  for providing fuel to the engine  14 . More specifically, the fuel tank  46  supplies fuel to a carburetor  50  as is commonly understood. Of course, the engine  14  could also be a non-carbureted engine, in which case, fuel would be supplied to a fuel injection system. The fuel tank  46  is filled by removing a fill cap  54 . Unlike prior art threaded fill caps, the fill cap  54  provides an air-tight seal when closing the fuel tank  46 . The fill cap  54  can be configured in any suitable manner to close and seal the tank  46 . 
   The fuel tank  46  also includes a vent  58  (shown schematically in  FIG. 1 ) that can be selectively opened and closed as will be described below. Any suitable vent configuration that permits selective opening and closing can be used. Some examples of vent configurations are shown in  FIGS. 5–11 . The vent  58  provides selective communication between the inside of the tank  46  and the atmosphere. When the vent  58  is open, the fuel tank  46  communicates with the atmosphere only via the vent  58 . When the vent  58  is closed, the fuel tank  46  does not communicate with the atmosphere. Therefore, closing the vent  58  reduces diurnal emissions from the tank  46 . The fuel tank  46  may be designed to accommodate pressure fluctuations caused by the expansion of fuel in the tank  46  when the vent  58  is closed. 
   The lawnmower  10   a  further includes a fuel vent closure device  62  that selectively opens and closes the vent  58 . The fuel vent closure device  62  preferably includes a valve  66  (also shown schematically in  FIG. 1 ) communicating between the vent  58  and a fuel vapor disbursal system, such as the air intake to the carburetor. The valve  66  can be of any suitable design. Several possible designs are shown in  FIGS. 12–23 , which will be discussed below. Opening the valve  66  opens the vent  58 , thereby providing communication between the inside of the tank  46  and the atmosphere. Closing the valve  66  closes the vent  58 , thereby preventing communication between the inside of the tank  46  and the atmosphere. 
   To reduce diurnal emissions from the fuel tank  46 , the valve  66  should be closed when the engine  14  stops running, and should remain closed until the engine  14  is ready to be run or is running. To accomplish this, the vent closure device  62  is actuated automatically in response to the manual operation of the engine control device  18 . In other words, when the operator releases the deadman lever to close the ignition ground switch  22  and stop the engine  14 , the vent closure device  62  automatically closes the valve  66 , thereby closing the vent  58 . When the operator engages the deadman lever to open the ignition ground switch  22  for starting the engine, the vent closure device  62  automatically opens the valve  66 , thereby opening the vent  58 . By incorporating the operation of the vent closure device  62  with the manual operation of the engine control device  18 , no additional action to open or close the vent  58  is required on behalf of the operator. 
   As seen in  FIG. 1 , the vent closure device  62  is remotely operated in response to movement of the linkage assembly  34 . More specifically, the linkage assembly  34  includes an extension member  70  that moves in the direction of the arrows  74  in response to movement of the linkage assembly  34 . When the operator actuates the engine control device  18 , the extension member  70  moves with the linkage assembly  34  to selectively open and close the valve  66 . An intermediate member  76  is coupled between the end of the extension member and a valve actuating member  78 . Movement of the valve actuating member  78  opens and closes the valve  66 . 
   It is appreciated that the vent closure device  62  need not be operated precisely in the manner shown in  FIG. 1 , but can be operated in other suitable manners using various other linkages or actuators known to those of ordinary skill in the art. Additionally, it is not necessary for the vent closure device  62  to automatically open the vent when the deadman lever is engaged for operation. Rather, the vent closure device  62  could operate automatically to close the vent  58  in response to release of the deadman lever, but could require additional action on behalf of the operator to manually open the vent  58  in order to run the engine  14 . 
   The lawnmower  10   a  also preferably includes a fuel shutoff device  82  that selectively blocks the fuel supply to the carburetor  50 . The fuel shutoff device  82  includes a valve  86  communicating between the fuel tank  46  and the carburetor  50 . The valve  86  can be of any suitable design. Several possible designs are shown in  FIGS. 12–23 , which will be discussed below. Opening the valve  86  provides fluid communication between the inside of the tank  46  and the carburetor  50 . Closing the valve  86  blocks fluid communication between the inside of the tank  46  and the carburetor  50 . 
   As shown in  FIG. 1 , the valve  86  for the fuel shutoff device  82  is actuated concurrently with actuation of the valve  66  for the vent closure device  62 . The same linkage discussed above with respect to the vent closure device  62  also actuates the fuel shutoff device  82 . Therefore, when the operator manually operates the engine control device  18  by releasing the deadman lever, the engine  14  stops running, the blade stops rotating, the fuel vent  58  is closed, and the fuel supply to the carburetor  50  is blocked. When the operator engages the deadman lever to permit running of the engine  14 , the engine  14  can be started, the brake  38  is released, the vent  58  is opened, and the fuel supply to the carburetor  50  is unblocked. 
   As will be discussed in more detail below, it is possible to incorporate both valves  66  and  86  in a single valve assembly  90 , thereby reducing the number of parts on the device. On the other hand, the fuel shutoff device  82  need not be actuated concurrently with, or via the same linkage as the vent closure device  62 , and could be completely separate from the vent closure device  62 . 
     FIG. 2  schematically illustrates a device  10   c  that is slightly different than the lawnmower  10   a . The device  10   c  is illustrated as being a pump or a pressure washer (see  FIG. 26 ), but could alternatively be a snow blower, a tiller, a string trimmer, or the like. The operation of the device  10   c  is substantially similar to the operation of the lawnmower  10   a , with some exceptions which will be discussed below. Like parts have been given like reference numerals. 
   The device  10   c  includes an engine control device  18   a  in the form of a speed control device. The speed control device includes a speed control lever  94  on a linkage assembly  34   a . The speed control lever  94  can be operated via a remote speed control lever (not shown) attached to a speed control cable  98 , or directly via a friction speed control lever  102  extending from the linkage assembly  34   a . As the device  10   c  does not include a rotating blade, such as is the case with a lawn mower, no brake is needed. 
   The fuel vent closure device  62  and the fuel shutoff device  82  operate in response to movement of the linkage assembly  34   a  in substantially the same manner as described above with respect to the lawnmower  10   a . Therefore, when the operator manually operates the engine control device  18   a  by lowering the speed to a point where the ignition ground switch  22  is closed, the engine  14  stops running, the fuel vent  58  is closed, and the fuel supply to the carburetor  50  is blocked. When the operator moves the speed control to a position where the ignition ground switch  22  is open and the engine  14  can run, the engine  14  can be started, the vent  58  is opened, and the fuel supply to the carburetor  50  is unblocked. 
     FIG. 3  schematically illustrates another manner of operating the fuel vent closure device  62  and the fuel shutoff device  82 . Specifically,  FIG. 3  illustrates a third engine control device  18   b  in the form of an on/off switch. The engine control device  18   b  can be used in conjunction with any devices, including, but not limited to, lawn tractors (not shown), generators  10   b  and  10   d  (see  FIGS. 25 and 27 ), pumps  10   c  (see  FIG. 26 ), and the like. 
   The engine control device  18   b  can be of any suitable construction. As seen in  FIG. 3 , the engine control device  18   b  includes a rotatable shaft  106  that passes through a sleeve  110 . A manually actuable knob portion  114  on the shaft  106  can be turned by the operator (either by hand or via a key) to cause the rotation of the shaft  106 . An ignition grounding member  118  is operable to ground the ignition circuit, and thereby stop the running of an engine, when the knob portion  114  is turned to the OFF position. 
   The shaft  106  is also coupled to the valve  66  for the vent closure device  62  and to the valve  86  for the fuel shutoff device  82 . Therefore, when the operator manually operates the engine control device  18   b  by turning the knob portion  114  to the OFF position, the engine stops running, the fuel vent is closed, and the fuel supply to the carburetor is blocked. When the operator turns the knob portion  114  to the ON position, the engine can be started, the vent is opened, and the fuel supply to the carburetor is unblocked. 
     FIG. 4  schematically illustrates a fourth engine control device  18   c  in the form of an on/off/start switch. The engine control device  18   c  operates in the same manner as the control device  18   b , but includes a START position for the automatic starting of the engine. When the operator turns the knob portion  114  to the START position, the engine starts as is understood. Therefore, when the operator manually operates the engine control device  18   c  by turning the knob (either by hand or via a key) portion  114  to the OFF position, the engine stops running, the fuel vent is closed, and the fuel supply to the carburetor is blocked. When the operator turns the knob portion  114  to the START position, the engine is automatically started, the vent is opened, and the fuel supply to the carburetor is unblocked. After the engine is started, the knob portion  114  returns to the ON position where the engine keeps running, the vent remains open, and the fuel supply to the carburetor remains unblocked. 
     FIGS. 5 and 6  show the fuel tank  46  and fuel tank vent  58  in greater detail. The vent  58  includes a connection port  120  adapted to be coupled to the valve  66  of the fuel vent closure device  62 . Any suitable conduit (not shown) can be used to provide communication between the connection port  120  and the valve  66 . As best seen in  FIG. 6 , the vent  58  can also include a baffle  122  that substantially prevents liquid fuel in the tank  46  from splashing out of the connection port  120 . The baffle  122  can be any suitable, gasoline-resistant material and is preferably in the form of a disk that has a diameter slightly smaller than the diameter of the vent sidewalls. With this construction, liquid fuel cannot splash into the connection port  120 , but air and fuel vapors can pass between the edge of the baffle  122  and the vent sidewalls for venting when the vent  58  is opened. The actual placement and design of the vent  58  in the tank  46  may be different than shown to get optimum separation of liquid and vapor fuel. The vent  58  could also be located in the fuel cap  54 . 
     FIG. 7  shows an alternative construction for preventing liquid fuel from splashing out of the connection port  120 . The vent  58  includes a gasoline-resistant membrane  126  that is substantially pervious to air and fuel vapor, but is substantially impervious to liquid fuel. When the vent  58  is opened, air and fuel vapor can pass through the membrane  126 , but liquid fuel cannot. 
     FIG. 6  also shows a fuel outlet port  130  located at the bottom of the tank  46 . The fuel outlet port  130  is adapted to be connected to a conduit (not shown) that communicates with the valve  86  of the fuel shutoff device  82 . It is important to note that the configuration of the fuel tank  46 , the vent  58 , and the fuel outlet port  130  is not limited to the configurations shown in the figures, but rather can be tailored to work in conjunction with a variety of devices having different types of fuel vent closure devices  62  and fuel shutoff devices  82 . 
   For example,  FIGS. 8 and 9  illustrate an alternative embodiment wherein the connection port  120  and the fuel outlet port  130  extend substantially parallel to one another in the same plane. Instead of using conduit to connect the ports  120  and  130  to the respective valves  66  and  86 , the valves  66  and  86  may be directly connected to the respective ports  120  and  130  outside of the fuel tank  46  as shown. The vent closure device  62  and the fuel shutoff device  82  may be part of a single valve assembly  90   a , as shown, or alternatively may be two interconnected valve assemblies (not shown). The valves  66  and  86  are connected via a shaft  134  which rotates in response to rotation of the actuating member  78  to open and close the valves  66  and  86 . 
     FIGS. 10 and 11  illustrate an alternative embodiment wherein the valve assembly  90   a  is located at least partially inside the fuel tank  46 . By positioning the valve assembly  90   a  inside the fuel tank  46 , the number of parts can be reduced. Any suitable method of securing the valve assembly  90   a  inside the fuel tank  46  can be used. With this embodiment, the valve  66  is part of the vent  58  so that vapors escaping the tank  46  pass through the valve  66  prior to exiting the connection port  120 . Likewise, air drawn into the tank  46  enters the connection port  120  prior to passing through the valve  66 . The valve  86  is also inside the fuel tank  46  such that fuel passes through the valve  86  prior to exiting through the fuel outlet port  130 . 
   There are numerous possible designs available for the valves  66  and  86 , and for the valve assembly  90 . For example,  FIGS. 12 and 13  illustrate one type of rotary valve assembly  90   b  that could be used. The valve assembly  90   b  includes an outer sleeve  138  having a vapor inlet  142 , a vapor outlet  146 , a fuel inlet  150 , and a fuel outlet  154 . It should be noted that the terms “vapor inlet” and “vapor outlet” are given with respect to the direction at which fuel vapor flows out of the tank  46 , however, if air from the surroundings is flowing into the tank  46 , the vapor outlet acts as an air inlet and the vapor inlet acts as an air outlet. 
   A rotatable shaft  158  is housed inside the outer sleeve  138 . The shaft  158  includes two transverse holes extending therethrough. Hole  162  selectively provides fluid communication between the vapor inlet  142  and the vapor outlet  146 , thereby acting as the valve  66 , while hole  166  selectively provides fluid communication between the fuel inlet  150  and the fuel outlet  154 , thereby acting as the valve  86 . Seals  170  are positioned between the sleeve  138  and the shaft  158  to seal the gap between the sleeve  138  and the shaft  158 . 
   As seen in  FIG. 12 , when the engine is not in operation, the shaft  158  is rotated such that the holes  162  and  166  are not aligned with the respective inlets  142 ,  150  and outlets  146 ,  154 . In this position, no air or fuel vapor can pass through the valve  66  and no fuel can pass through the valve  86 . The orientation shown in  FIG. 12  is used when the engine is not operating. In  FIG. 13 , the shaft  158  is rotated such that the holes  162  and  166  provide fluid communication between the respective inlets  142 ,  150  and outlets  146 ,  154 . The orientation shown in  FIG. 13  is used during times of engine operation. 
   While the valve assembly  90   b  shown in  FIGS. 12 and 13  is illustrated with the inlets  142 ,  150 , the outlets  146 ,  154 , and the holes  162 ,  166  all being in the same plane, it should be understood that the components of the valve  66  and the valve  86  can be in different planes as well. Such would be the case when the valve assembly  90   b  were used with the embodiments shown in  FIGS. 8–11 . Of course, with the valves  66  and  86  in different planes, the inlets  142 ,  150  and the outlets  146 ,  154  could be positioned anywhere along the circumferential periphery of the sleeve  138  to suit the configuration of the tank  46  and the ports  120 ,  130 . 
     FIGS. 14 and 15  illustrate another valve assembly  90   c . The valve assembly  90   c  is a schematic of a sliding-spool directional-flow valve and includes an outer shell  174  having inlets  142 ,  150  and outlets  146 ,  154  that communicate with an inner cavity  178 . The inner cavity  178  is open at one end for slidably receiving the end of a spool  182 . The spool  182  includes four sealing disks  186  mounted in spaced relation from one another. Each of the disks  186  includes a seal ring  190  that can engage portions of the cavity wall as shown to selectively seal off portions of the cavity  178  between the disks  186 . 
   The spool  182  is slidable into and out of the cavity  178  as seen in  FIGS. 14 and 15 . A wiper seal  194  adjacent the open end of the cavity  178  seals the open end of the cavity  178  to substantially prevent vapors and fuel from leaking out between the spool  182  and the shell  174  during operation.  FIG. 14  illustrates the closed position for the valves  66  and  86  and  FIG. 15  illustrates the open position for the valves  66  and  86 . 
     FIGS. 16 and 17  illustrate a valve assembly  90   d  that is a schematic of a poppet valve. The operation of the valve assembly  90   d  is similar to the operation of the valve assembly  90   c  and like parts have been given like reference numerals. Instead of four disks  186 , the spool  182  has only one disk  186 . In addition to the single disk  186 , poppets  198  formed on the spool  182  engage portions of the cavity wall to selectively seal off portions of the cavity  178  between the poppets  198  and the disk  186 . A separate end cap  202  closes the end of the cavity  178  and includes the wiper seal  194 .  FIG. 16  illustrates the closed position for the valves  66  and  86  and  FIG. 17  illustrates the open position for the valves  66  and  86 . 
     FIGS. 18–20  illustrate yet another valve assembly  90   e . The valve assembly  90   e  is a schematic of an axial-sealing rotary valve and includes a housing  206  defining the inlets  142 ,  150  and the outlets  146 ,  154 . A rotary member  210  is positioned within the housing  206  and rotates with respect to the housing  206  by actuation of a lever arm  214 . The rotary member also includes a valve segment  218  having a vent aperture  222  and a fuel aperture  226  that selectively provide communication between the respective inlets  142 ,  150  and outlets  146 ,  154 . Seals  230  are provided between the valve segment  218  and the housing  206 . 
   When the valves  66  and  86  are in the open position, as shown in  FIG. 18 , the apertures  222  and  226  are aligned with the respective inlets  142 ,  150  and outlets  146 ,  154  to provide fluid communication therebetween. When the valves  66  and  86  are in the closed position, as shown in  FIGS. 19 and 20 , the apertures  222  and  226  are not aligned with the respective inlets  142 ,  150  and outlets  146 ,  154  and fluid communication is blocked. 
     FIGS. 21–23  illustrate yet another valve assembly  90   f . The valve assembly  90   f  is an eccentric wheel valve and includes a housing  234  having inlets  142 ,  150  and outlets  146 ,  154 . A rotary member  238  is positioned inside the housing  234  and has an actuating portion  242  (see  FIG. 23 ) extending out of the housing  234  through an end cap  246 . The rotary member  238  includes upper and lower recesses  250  and  254 , respectively. 
   A blocking member  258  is pinned in each of the recesses  250  and  254  and rolls along the inner wall of the housing  234  to selectively block and unblock the inlets  142 ,  150  as the rotary member  238  rotates. Of course the blocking members  250  could also be positioned to selectively block and unblock the outlets  146 ,  154 . Seals  262  (see  FIG. 23 ) isolate the recesses  250  and  254  from one another and from the environment outside of the housing  234 .  FIG. 21  illustrates the open position for the valves  66  and  86  and  FIGS. 22 and 23  illustrate the closed position for the valves  66  and  86 . 
   Each of the valve assemblies  90  discussed above can be made from any suitable fuel-resistant materials and can be used interchangeably if the design of the device  10  so permits. It is understood that modifications to the tank  46  and the valve actuating linkages may be required depending on the type of valve assembly  90  used. Alternatively, changes to the valve assemblies  90  can be made to suit the tank and the actuating linkage configurations. It should also be noted that other valve assemblies  90  not shown or described can also be substituted. For example, while the valves  66  and  86  are shown to typically open and close at the same time, alternative arrangements can be substituted where the vent valve  66  may be positioned or timed to open prior to the fuel valve  86 , or vice-versa. Furthermore, the valve assemblies  90  need not incorporate both of the valves  66  and  86  as shown. Two separate valves  66  and  86  could be used and could incorporate any of the valve types discussed above. 
   Various features of the invention are set forth in the following claims.