Abstract:
An apparatus for providing fuel comprises a fuel handling portion and an air handling portion. The fuel handling portion comprises a fuel tank adapted to store fuel as well as a fuel nozzle in fluid communication with the fuel tank and adapted to dispense fuel from the fuel tank. The air handling portion comprises an air tank adapted to be filled with pressurized gas from a pressurized gas source. After the pressurized gas source is removed, the air handling portion is operative to apply the pressurized gas from the air tank to the fuel in the fuel tank so as to provide a motive force for dispensing fuel through the fuel nozzle.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to apparatus and methods for obtaining, transporting, storing, and dispensing fuel. The present invention further relates to apparatus and methods for processing fuel. 
       BACKGROUND OF THE INVENTION 
       [0002]    Operators of motorized equipment such as auto enthusiasts, pilots, boaters, landscapers, and the like often find themselves requiring gasoline without having a convenient source of suitable fuel. To make matters worse, in many cases, a ready source of electrical power is also not available. During these situations, the only realistic fueling solution is frequently the ubiquitous five-gallon gas can. The user fills several of these gas cans at a remote gas station and then transports them to where they will be needed. The user then lifts the heavy gas cans above the vehicle&#39;s fuel tank and uses a spout or funnel to direct the fuel into the vehicle by gravity feed. In the case of large vehicles and high-wing airplanes, the user may even need to climb a stepstool or ladder with the cans in order to access the vehicle&#39;s fuel tank. 
         [0003]    To make matters worse, in addition to being inconvenient and physically demanding, the use of gas cans in this manner is often dangerous from the perspective of explosion and fire, and also frequently results in fuel spillages that can damage a vehicle&#39;s paint. A user may even lose their grip on the gas can while fueling and allow the gas can to inadvertently drop onto the vehicle and cause damage. Finally, fueling with gas cans is slow because of a gas can&#39;s narrow opening and its dependence on gravity feed. Taking an inordinate amount of time to fuel a vehicle is especially inconvenient when the weather is cold or wet and the refueling is performed while the operator is exposed to the elements. 
         [0004]    A further source of issues for the equipment operators mentioned above is the inclusion of alcohol in many fuels. Almost all regularly available automobile gasoline now contains 10% ethanol as a result of federal legislation. Nevertheless, ethanol can destroy critical fuel system and engine components if these components were not specifically designed for resistance to alcohol. Ethanol also has a tendency to phase separate from gasoline when exposed to water, creating a corrosive layer of water and ethanol at the bottom of a fuel tank. For these reasons, alcohol-containing fuels are not approved for many motorized vehicles. A large percentage of the piston-engine aircraft fleet, for example, is certified to run on automobile fuel so long as it is free of alcohol. Despite this, however, a pilot typically must use very expensive and highly polluting leaded aviation fuel instead of automobile fuel because the automobile fuel contains ethanol. 
         [0005]    For the foregoing reasons, there is a need for improved fueling system designs that allow fuel to be obtained, transported, stored, and dispensed in a safe, efficient, and convenient manner. For those vehicles that cannot tolerate alcohol in the fuel, there is further a need for these new fueling systems to be capable of removing any ethanol from the fuel before the fuel is dispensed into the vehicle. 
       SUMMARY OF THE INVENTION 
       [0006]    Embodiments of the present invention address the above-identified needs by providing fueling systems that allow fuel to be obtained, transported, stored, and dispensed in a safe, efficient, and convenient manner. Embodiments of the invention further provide fueling systems capable of removing any ethanol from the fuel before the fuel is dispensed into a vehicle. 
         [0007]    In accordance with an aspect of the invention, an apparatus for providing fuel comprises a fuel handling portion and an air handling portion. The fuel handling portion comprises a fuel tank adapted to store fuel as well as a fuel nozzle in fluid communication with the fuel tank and adapted to dispense fuel from the fuel tank. The air handling portion comprises an air tank adapted to be filled with pressurized gas from a pressurized gas source. After the pressurized gas source is removed, the air handling portion is operative to apply the pressurized gas from the air tank to the fuel in the fuel tank so as to provide a motive force for dispensing fuel through the fuel nozzle. 
         [0008]    In accordance with another aspect of the invention, a method of providing fuel comprises filling a fuel tank with fuel, the fuel tank in fluid communication with a fuel nozzle. Subsequently an air tank is pressurized with a gas from a pressurized gas source. With the pressurized gas source removed, fuel is dispensed from the fuel tank through the fuel nozzle while allowing pressurized gas from the air tank to provide a motive force for dispensing the fuel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description and accompanying drawings where: 
           [0010]      FIG. 1  shows a schematic of at least a portion of a fueling system in accordance with a first illustrative embodiment of the invention; 
           [0011]      FIG. 2  shows a flow diagram of an illustrative method for utilizing the  FIG. 1  fueling system to dispense fuel; 
           [0012]      FIG. 3  shows a perspective view of a working prototype of the  FIG. 1  fueling system implemented in a cart; 
           [0013]      FIG. 4  shows a schematic of at least a portion of a fueling system in accordance with a second illustrative embodiment of the invention; 
           [0014]      FIG. 5  shows a flow diagram of a method for utilizing the  FIG. 4  fueling system to remove alcohol and dispense fuel; 
           [0015]      FIGS. 6A and 6B  show flow diagrams of an automated separation process in the  FIG. 4  fueling system; 
           [0016]      FIG. 7  shows an electrical schematic of an illustrative detector in the  FIG. 4  fueling system; 
           [0017]      FIG. 8  shows a flow diagram of alternative steps for use in the  FIGS. 6A and 6B  process; and 
           [0018]      FIG. 9  shows a perspective view of a working prototype of the  FIG. 4  fueling system implemented in a cart. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    The present invention will be described with reference to illustrative embodiments. For this reason, numerous modifications can be made to these embodiments and the results will still come within the scope of the invention. No limitations with respect to the specific embodiments described herein are intended or should be inferred. 
         [0020]      FIG. 1  shows a schematic of at least a portion of a fueling system  100  in accordance with a first illustrative embodiment of the invention. The fueling system  100  can be roughly broken into two portions. An air handling portion  105  allows the storage and transport of compressed air, and also provides a means for a fuel tank  110  to be pressurized with air. A fuel handling portion  115  allows the storage and transport of fuel, and also provides a means for the fuel to be dispensed. 
         [0021]    Broken down even further, the air handling portion  105  comprises an air path  120  between an air tank  125  and the fuel tank  110 . Along a section of the air path  120  immediately after the air tank  125 , one finds an air tank pressure gauge  130 , an air tank safety relief valve  135 , an air tank fill valve  140 , an air tank valve  145 , and a pressure regulator  150 . Immediately after the pressure regulator  150 , one finds a fuel tank relief valve  155 , an air filter  160 , an air shutoff valve  165 , a fuel tank safety relief valve  170 , and a fuel tank pressure gauge  175 . In the fuel handling portion  115  of the fueling system  100 , one finds the fuel tank  110  with a fuel cap  112 , as well as a fuel path  180  that connects the bottom of the fuel tank  110  to a fuel shutoff valve  185 , a fuel filter  190 , and finally, a fuel nozzle  195 . The fuel path  180  from the fuel filter  190  to the fuel nozzle  195  comprises a fuel hose  182 . 
         [0022]    For safety purposes, the fueling system  100  further comprises an electrical grounding system that allows all the components of the fueling system  100  to be electrically tied to the vehicle being fueled. This equalizes the electrical potential between the fueling system  100  and the vehicle, thereby reducing the chance of a spark forming during fueling. A bonding strap  198  is attached to the fuel tank  110  and is available to tie the fueling system  100  to the vehicle being fueled. The electrically conductive conduits and fixtures forming the fueling system  100 , in addition to a grounding wire integral to the fuel hose  182 , assure that all the parts of the fueling system  100  achieve the same electrical potential as the bonding strap  198 . 
         [0023]    When the air handling portion  105 , the fuel handling portion  115 , and the grounding system are combined, one achieves a fueling system  100  that allows fuel to be obtained, transported, stored, and dispensed in a safe, efficient, and convenient manner. Pressurization provided by the air handling portion  105  allows the fuel tank  110  to be pressurized with air. Fuel flow from the fuel tank  110 , in turn, is driven by this air pressure (i.e., air pressure creates the motive force for the fuel flow) and does not depend solely on gravity. Ultimately, a user of the fueling system  100  receives a fueling experience similar to that of a conventional gas pump, but without the need for an immediate source of electrical power. 
         [0024]      FIG. 2  shows a flow diagram of an illustrative method  200  for utilizing the fueling system  100  to dispense fuel. The first set of steps allows the fuel tank  110  to be pressurized with air from the air tank  125 . In step  205 , the fuel tank  110  is vented of any excess pressure by closing the air tank valve  145 , and then opening the air shutoff valve  165  and the fuel tank relief valve  155 . Once this venting is accomplished, the user then shuts the air shutoff valve  165  and the fuel tank relief valve  155  and moves onto step  210 , wherein the fuel tank  110  is filled with fuel. Here, the user merely removes the fuel cap  112  of the fuel tank  110  and dispenses fuel into the fuel tank  110  from a convenient source of fuel (e.g., an automobile gas station). After the fuel cap  112  is replaced, the air tank  125  is then filled with compressed air in step  215 . Filling the air tank  125  may be performed by coupling a source of compressed air (i.e., an air compressor) to the air tank fill valve  140  and filling the air tank  125  while the air tank valve  145  remains closed. 
         [0025]    The fuel tank  110  is then ready to be pressurized. In step  220 , the fueling system  100  is grounded to the vehicle being fueled. In step  225 , the air tank valve  145  and the air shutoff valve  165  are opened causing compressed air to travel from the air tank  125  through the pressure regulator  150  and the air filter  160  into the fuel tank  110 . The pressure regulator  150  reduces the air pressure from the fill pressure in the air tank  125  (e.g., 120 pounds per square inch (psi)) to something substantially lower than that (e.g., 10 psi). The air filter  160 , in turn, removes any contaminants from the compressed air before the contaminants have a chance to enter the fuel tank  110 . Pressurized in this manner, the fuel tank  110  is ready to dispense fuel. In step  230 , the user opens the fuel shutoff valve  185  and positions the fuel nozzle  195  in a vehicle&#39;s fuel tank opening. Actuating the fuel nozzle  195  causes fuel to first travel through the fuel filter  190  and then into the vehicle. 
         [0026]    Notably, during the entire method  200  described above, any potentially dangerous over-pressure events are avoided by the air tank safety relief valve  135  and the fuel tank safety relief valve  170 . The air tank safety relief valve  135  may be configured to vent when the pressure in the air tank  125  exceeds, for example, 145 psi. The fuel tank safety relief valve  170  may be configured to vent when the fuel tank  110  exceeds, as another example, 25 psi. 
         [0027]    The fueling system  100  may be physically implemented in several different forms.  FIG. 3 , for example, shows a perspective view of a working prototype of the fueling system  100  implemented in a cart  300  with two rear wheels  305 , a front base  310 , and two handles  315 . A region  320  of the working prototype comprised the air tank pressure gauge  130 , the air tank safety relief valve  135 , and the air tank fill valve  140 ; while another region  325  comprised the air tank valve  145 , the pressure regulator  150 , the fuel tank relief valve  155 , the air filter  160 , the air shutoff valve  165 , the fuel tank safety relief valve  170 , and the fuel tank pressure gauge  175 . A region  330  near the bottom of the cart  300  comprised the fuel shutoff valve  185  and the fuel filter  190 . This prototype and others displayed excellent reliability and robustness. Fuel flow rates were often greater than those provided by gas pumps at automobile gas stations. For example, flow rates greater than eight gallons per minute were achieved with a ⅜-inch diameter fuel hose  182  even with a partially used fuel filter  190 . 
         [0028]    Advantageously, the fueling system  100  can be constructed using conventional, off-the-shelf components, reducing the need to manufacture custom parts. In one configuration, for example, the air tank  125  and the fuel tank  110  may comprise conventional air-tight metallic tanks. Both tanks are preferably rated to about five times the normal maximum operating pressure to provide a wide margin of safety. The air tank valve  145 , the fuel tank relief valve  155 , the air shutoff valve  165 , and the fuel shutoff valve  185  may comprise conventional ball valves, while the air tank fill valve  140  may comprise a conventional Schrader valve. The air tank safety relief valve  135  and the fuel tank safety relief valve  170  may comprise conventional adjustable pressure relief valves. The pressure gauges  130 ,  175 , the pressure regulator  150 , the air filter  160 , the fuel filter  190 , and the fuel nozzle  195  may just be conventional components readily sourced from a number of commercial vendors. Lastly, the air path  120  and the fuel path  180  that tie the various other components together may comprise conventional metallic fittings, metallic tubing, conventional rubber hoses, and a conventional grounded fuel hose  182 . 
         [0029]    As described earlier, the inclusion of ethanol in a lot of fuels provides a barrier to the use of that fuel in many vehicles.  FIG. 4  shows a schematic of at least a portion of fueling system  400  in accordance with a second illustrative embodiment of the invention that addresses that issue. The fueling system  400  includes an air handling portion  105  identical to the air handling portion  105  in the fueling system  100  (and therefore marked with the identical reference numeral). The fuel handling portion  410 , on the other hand, comprises a number of added elements that allow ethanol to be removed from the fuel using an automated separation process. The fuel handling portion  410  comprises a fuel tank  415  with a fuel cap  417 , and a bonding strap  418 . The fuel tank  415  has an output at its bottom that is split into two branches. On a first branch, the fuel flow is directed through a first fuel shutoff valve  420  into a first fuel filter  425  and ultimately to a fuel nozzle  430  via a fuel hose  432 . On a second branch, the fuel is directed to a second fuel shutoff valve  435 , to a second fuel filter  440 , and to a motorized source selector valve  445 . The source selector valve  445  is connected to a water source  450 . After the motorized source selector valve  445 , the fuel (or the water or ethanol-water, as the case may be) is directed to a detector  455 , to a pump  460 , and finally to a motorized waste selector valve  465 . The waste selector valve  465  determines whether the fluid in the fuel tank  415  is pumped to a waste container  470  or back to the top of the fuel tank  415 . 
         [0030]      FIG. 5  goes on to show a flow diagram of a method  500  for utilizing the fueling system  400  to remove alcohol from fuel and ultimately dispense the alcohol-free fuel into a vehicle. In step  505 , the fuel tank  415  is vented in a manner similar to step  205  in the method  200 . Next, in step  510 , ethanol-containing fuel is added to the fuel tank  415  in a manner similar to step  210 . In the next step, however, the method  500  diverges from that described earlier. In step  515 , a quantity of water (e.g., about one gallon) is also added to the fuel tank  415 . Moreover, in step  520 , additional water is added to the water source  450 . In step  525 , the automated separation process  600  is initiated. 
         [0031]    The automated separation process  600  in the fueling system  400  is controlled by a controller  475 . The controller  475  receives signals from the detector  455  and controls the states of the source selector valve  445 , the pump  460 , and the waste selector valve  465 . The automated separation process  600  leverages the fact that ethanol in fuel phase separates from that fuel when exposed to water, thereby forming an ethanol-water layer that is heavier than the remaining fuel and settles below that fuel. Causing the phase separation to occur and then removing the bottom layer of ethanol-water thereby becomes a means of removing the alcohol from the fuel. 
         [0032]      FIGS. 6A and 6B  show flow diagrams of the illustrative automated separation process  600  in the fueling system  400 . In step  602 , the controller  475  sets a variable FILLS to zero (i.e., FILLS=0). It then commands the source selector valve  445  to route fuel from the second fuel filter  440  to the detector  455  (step  604 ), and also commands the waste selector valve  465  to route fluids from the pump  460  back to the top of the fuel tank  415  (step  606 ). Subsequently, in step  608 , the controller  475  commands the pump  460  to turn on and run for a time PUMPTIME 1  (e.g., 10 minutes). This starts to circulate the fuel-ethanol-water from the bottom of the fuel tank  415  to its top, thereby thoroughly mixing the fuel-ethanol-water and starting the process of phase separation. After the pump  460  is stopped, the controller  475  in step  610  commands the waste selector valve  465  to start sending fluid to the waste container  470  instead of back to the top of the fuel tank  415 . 
         [0033]    In steps  612  and  614 , the controller  475  attempts to remove any ethanol-water that has collected at the bottom of the fuel tank  415 . This involves the use of the detector  455 .  FIG. 7  shows an exemplary electrical schematic of the detector  455 . In the present embodiment, the detector  455  comprises two brass plugs  705  that are spaced apart and between which the fluids from the fuel tank  415  are allowed to flow. Ethanol-water creates a high conductivity between the brass plugs  705 , while fuel creates a low conductivity. The conductivity is detected through the use of a DC voltage source, a pull-up resistor  710 , and a series resistor  715 , as shown in the schematic. A high conductivity between the brass plugs  705  causes the voltage sent to the controller  475  to be low, and vice versa. 
         [0034]    Again referring to  FIGS. 6A and 6B , in step  612 , the pump  460  is turned back on, sending the fluid from the bottom of the fuel tank  415  to the waste container  470 . In step  614 , the controller  475  receives the conductivity, CNDCT, from the detector  455  and determines whether CNDCT is higher than a predetermined conductivity threshold, CTHRESH. If CNDCT&gt;CTHRESH, meaning that the detector  455  is seeing ethanol-water, the pump  460  is allowed to keep on pumping. When CNDCT&lt;CTHRESH, meaning that the detector  455  is seeing primarily ethanol-free fuel, the controller  475  turns off the pump  460  in step  616 . 
         [0035]    In the present embodiment, additional water is incrementally added to the fuel in the fuel tank  110  and allowed to circulate for PUMPTIME 1  in a series of “water fills” in order to assure that the substantial majority of ethanol has been successfully removed. The additional water fills also aid in diluting the ethanol-water mixture in the waste container  470 , making its ultimate disposal less hazardous and easier from a regulatory standpoint. In step  618 , the controller  475  determines whether the fuel in the fuel tank  415  has been exposed to a predetermined number of water fills, MINFILLS. If not, the waste selector valve  465  in step  620  is set such that it again routes fluids to the top of the fuel tank  415  rather than to the waste container  470 . Subsequently, in step  622 , the controller  475  commands the source selector valve  445  such that it receives water from the water source  450  rather than from the second fuel filter  440 . The pump  460  is then allowed to run for a time PUMPTIME 2  in step  624 . The time PUMPTIME 2  is preferably set so that about one gallon of water is caused to be pumped from the water source  450  into the fuel tank  415 , although other water quantities may be chosen if desired. With the additional water added in this manner, the variable FILLS is incremented by one in step  626 . Steps  604 - 626  are repeated until the number of additional water fills is equal to MINFILLS. At that point, the process  600  progresses to step  628  in  FIG. 6B . 
         [0036]    The remaining steps in the automated separation process  600  give any additional ethanol-water in the fuel tank  415  additional time to settle out without the fluid in the fuel tank  415  being circulated by the pump  460 . This additional time is called “dwell time.” Dwell time is measured by having a counter, CNTR, in the controller  475  advance until it reaches a predetermined counter value, CNTRDWELL. In step  628 , CNTR is set to zero. In step  630 , the detector  455  determines whether CNDCT exceeds another predetermined conductivity value, CHIGH. CHIGH is a conductivity value greater than CTHRESH, and is used during the dwell time to avoid having the user wait through the entire dwell time when there is still a lot of ethanol-water collecting at the bottom of the fuel tank  415 . If CNDCT&gt;CHIGH in step  630 , the controller  475  turns the pump  460  back on (step  632 ) and runs the pump  460  for a time PUMPTIME 3  (e.g., two seconds), thereby using the pump  460  to send more fluid to the waste container  470 . The pump  460  then turns back off, reinitiating the dwell time by reverting back to step  628 . If CNDCT&lt;CHIGH in step  630 , the CNTR is advanced by one in step  634  and the controller  475  proceeds to step  636 . 
         [0037]    Step  636  determines whether CNTR&gt;CNTRDWELL has been achieved, meaning that the fueling system  400  has waited the predetermined dwell time in order to allow complete phase separation. If no, the controller  475  proceeds back to step  630 . If yes, the controller  475  moves to step  638 , where it again checks if CNDCT&gt;CTHRESH. This is the final measurement to determine if all the ethanol-water has been removed from the fuel tank  415 . If the result is no, the controller  475  assumes that all the ethanol-fuel has been removed. If the answer is yes, the controller  475  assumes that ethanol-water still remains, and moves back to step  632 . The pump  460  is again run for PUMPTIME 3  and the dwell time starts again in step  628 . 
         [0038]    With the alcohol now removed from the fuel, the fuel can be dispensed in a manner similar to the fueling system  100 . Again referring to  FIG. 5 , step  530  has the user fill the air tank  125  with compressed air in a manner similar to step  215 . In step  535 , the fueling system  400  is properly grounded to the vehicle. Lastly, in steps  540  and  545 , the fuel tank  110  is pressurized and the fuel is dispensed as was done in steps  225  and  230 , respectively. 
         [0039]    The illustrative automated separation sequence can be modified and the results would still come within the scope of the invention. One such modification involves replacing step  608  in the automated separation process  600  shown in  FIGS. 6A and 6B  with the sequence of steps  802 - 806  shown in  FIG. 8 . Step  608  in the process  600  causes the fuel-ethanol-water to be circulated through the fuel tank  110  for the time PUMPTIME 1 . Steps  802 - 806  in  FIG. 8 , in contrast, use the detector  455  to determine the circulation time. More particularly, in step  806 , CNDCT is measured to see if it is below a predetermined conductivity, CCIRC. If yes, it is assumed that most, if not all, of the ethanol-water has phase separated from the fuel and is at the bottom of the fuel tank  415 . The circulation process may then be stopped. If no, it is assumed that more circulation is required and that process is allowed to continue. 
         [0040]    Like the fueling system  100 , the fueling system  400  may also be manufactured using conventional, commercially available components. The fuel tank  415 , the first fuel shutoff valve  420 , the fuel hose  432 , and the fuel nozzle  430  may comprise the same components as their respective counterparts in the fueling system  100 . That said, it is preferred that the first fuel filter  425  be of the “water-block” variety to create a final barrier to dispensing any water into a vehicle. Suitable water-block fuel filters are conventional and are commercially available. Likewise, the second fuel shutoff valve  435  may comprise a conventional ball valve, while the second fuel filter  440  may comprise a conventional fuel filter (non water-block type). The pump  460  may be a conventional electric fuel pump and the selector valves  445 ,  465  may be conventional electric fuel tank selector valves. 
         [0041]    For logic functions, the controller  475  may include any suitable, commercially available microcontroller chip such as, but not limited to, a PIC-type microcontroller. Once its functions are understood, one of ordinary skill in the electronics arts would recognize how to program the microcontroller and how to configure any additional circuitry in the controller  475  needed to interface the microcontroller with the pump  460 , the detector  455 , and the selector valves  445 ,  465 . Moreover, programming and interfacing microcontrollers are described in a number of books, including Valdes-Perez et al.,  Controllers: Fundamentals and Applications with PIC , CRC Press, 2009, which is hereby incorporated by reference herein. Power may be supplied to the controller  475  by battery (standard or rechargeable) or by line power. Displays may be added to the controller to indicate the various phases of the separation process such as draining, settling, and separating. Alarms and other features may also be programmed into the controller  475  to indicate fouled filters, inoperative pumps, out-of-range detector measurements, electrical faults, and the like. 
         [0042]      FIG. 9  shows a perspective view of a working prototype of the fueling system  400  implemented in a cart  900  with two rear wheels  905 , a front base  910 , and two handles  915 . A region  920  of the working prototype comprised the air tank pressure gauge  130 , the air tank safety relief valve  135 , and the air tank fill valve  140 ; while another region  925  comprised the air tank valve  145 , the pressure regulator  150 , the fuel tank relief valve  155 , the air filter  160 , the air shutoff valve  165 , the fuel tank safety relief valve  170 , the fuel tank pressure gauge  175 , the first fuel shutoff valve  420 , and the first fuel filter  425 . A region  930  near the bottom of the cart  900  comprised the second fuel shutoff valve  435 , the second fuel filter  440 , the motorized source selector valve  445 , the detector  455 , the pump  460 , the motorized waste selector valve  465 , and the controller  475 . Additional hoses were provided for connection to the water source  450  and the waste container  470  (not shown). In this prototype, it will be noted that the first fuel filter  425  (e.g., water-block type) was elevated on the cart  900  so that it was higher than the fuel tank  415 . Such a configuration is preferable; it helps to ensure that the first fuel filter  425  is not flooded with ethanol-water from the fuel tank  415 , and that the first fuel filter  425  provides the greatest effectiveness in removing any residual water from the fuel while the fuel is ultimately being dispensed. 
         [0043]    It should again be emphasized that the above-described embodiments of the invention are intended to be illustrative only. Other embodiments can use different types and arrangements of elements, as well as different process steps, for implementing the described functionality and the results will still come within the scope of the invention. For example, in another embodiment, the air tank may not be present or the air tank may be removable, and the fueling system may be configured to receive compressed air from an external source such as an external compressed air tank or an air compressor. In another example, a detector might use capacitive, inductive, or optical measurements instead of a conductivity measurement to determine the presence and absence of ethanol-water. Alternatively or additionally, another embodiment may even comprise several air tanks and/or several fuel tanks to increase the capacity of the fueling system as well as to provide for even faster fuel flow rates. These numerous alternative embodiments within the scope of the invention will be apparent to one skilled in the art. 
         [0044]    Moreover, all the features disclosed herein may be replaced by alternative features serving the same, equivalent, or similar purposes, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.