Abstract:
A device is provided to prevent the accidental introduction of an incorrect liquid into a tank, such as the introduction of gasoline into the fuel system of a diesel fuel container. The device discriminates between nozzle diameters, allowing entrance of nozzle diameters at or greater than a predetermined minimum diameter while inhibiting entrance of nozzles having diameters less than the predetermined minimum diameter. A closure mechanism prevents access to a fuel container interior and a releasable locking mechanism responsive to nozzle diameters allows the closure mechanism to open and close to allow access to the fuel container interior.

Description:
[0001]    This application claims priority from U.S. Prov. Pat. App. No. 62/265,786, filed Dec. 10, 2015, entitled “Diesel Fuel Guard.” 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates to vehicles powered by internal combustion engines and in particular to a device for preventing incorrect fueling operations for diesel-powered vehicles. 
       BACKGROUND OF THE INVENTION 
       [0003]    In the past few decades, government limits on the use of leaded fuels have led to the use of smaller gasoline fuel nozzles, designed to fit through “restrictors” in the fill tubes of gasoline-powered vehicles. These restrictors were designed to prevent the introduction of leaded gas into vehicles containing catalytic converters, which would be “poisoned” by the tetraethyl lead contained in older gasoline formulations. Another recent trend has been increasing use of diesel engines to power automobiles and other smaller vehicles, using low-sulfur diesel fuels. As a result, vehicles which an operator might have assumed to require gasoline in the past may now require diesel fuel instead, with correspondingly increased chances of incorrect fueling occurring. 
         [0004]    Non-leaded gasoline fill nozzles are approximately 13/16 inch in outer diameter, with gasoline-powered vehicles being configured with restrictors in their gasoline fill tubes having openings corresponding to this size nozzle. Small vehicle diesel fill nozzles are slightly larger, approximately 15/16 inch in diameter, corresponding to the size of the older leaded gas fill nozzles. The restrictors in diesel-powered vehicles must then have openings correspondingly larger to accommodate this slightly larger size fill nozzle. 
         [0005]    As a result, the restrictors in gasoline-powered vehicles have openings too small to allow insertion of low-sulfur #2 diesel fuel nozzles (as these nozzles have the same size as the old leaded fuel nozzles, the insertion of which the restrictor was designed to prevent). This situation generally minimizes the chance of accidentally introducing diesel fuel into a gasoline-powered vehicle. Unfortunately, the opposite error of accidentally introducing gasoline or diesel exhaust fluid (DEF) into a diesel-powered vehicle is not prevented by the restrictor mechanism, as the smaller gasoline fill nozzle fits easily through the larger opening in the diesel fill tube restrictor. In the past, when diesel power was generally employed only for larger trucks and very few smaller vehicles, this fueling error was less common. With the advent of modern diesel-powered smaller vehicles, such as those employing common-rail direct fuel injection, increasing numbers of smaller vehicles are diesel-powered with the result that fueling errors are now more common. 
         [0006]      FIG. 1  shows a view  100  of a motor vehicle  106  having an internal combustion engine  104  and a fuel tank  116  connected to the internal combustion engine  104  by a fuel line  114 . A fuel pump  102  supplies fuel to nozzle  112  through tube  110 . Nozzle  112  is inserted through fill tube  108  to enable filling of fuel tank  116 . Internal combustion engine  104  may be a gasoline engine, in which case fuel pump  102  should be configured to supply gasoline through tube  110  to fuel tank  116  to ensure proper operation of internal combustion engine  104 . Alternatively, internal combustion engine  104  may be a diesel engine, in which case fuel pump  102  should be configured to supply diesel fuel through tube  110  to fuel tank  116  to ensure proper operation of the diesel engine. One possible incorrect fueling operation occurs if internal combustion engine  104  is a diesel engine and fuel pump  102  is configured to supply gasoline or DEF through tube  110  to nozzle  112 . Another possible incorrect fueling operation occurs if internal combustion engine  104  is a gasoline engine and fuel pump  102  is configured to supply diesel fuel through tube  110  to nozzle  112 . In either of these two incorrect fueling operations, internal combustion engine  104  would be supplied by the wrong type of fuel through fuel line  114  leading from fuel tank  116 , which in both scenarios would contain the wrong type of fuel or fluid (i.e., gasoline or DEF for the diesel engine, or diesel fuel for the gasoline engine). As described above, diesel fill nozzles are generally configured to be too large in diameter to allow the filling of gasoline fuel tanks with diesel fuel, as the nozzle will not fit through the restrictor hole. Conversely, gasoline fill nozzles are small enough in diameter to easily fit into the fill tubes of diesel-powered vehicles. 
         [0007]      FIGS. 2 and 3  show before and after positions of a diesel nozzle entering a diesel fuel tube in the prior art.  FIG. 2  shows a before position  200  of a diesel nozzle  202  entering a diesel fill tube  204  along directional arrow  216 . Diesel fill tube  204  includes an outer tube  206  and inner tube  208 , where outer tube  206  and inner tube  208  are separated by a restrictor  210  with entrance hole  212  configured to fit closely around the outer diameter of diesel nozzle  202 .  FIG. 3  shows an after position  220  of the diesel nozzle  202  of  FIG. 2  fitting closely into entrance hole  212  and into the inner tube  208 . In this configuration, diesel nozzle  202  is positioned to supply diesel fuel to the diesel fuel tank (not shown) attached to inner tube  208 .  FIG. 3  illustrates a correct fueling configuration in which the proper type of fuel (i.e., diesel fuel) may be introduced to a diesel-powered vehicle. 
         [0008]      FIGS. 4 and 5  show before and after positions of a gasoline or DEF nozzle entering a diesel fuel tube in the prior art.  FIG. 4  shows a before position  230  of a gasoline or DEF nozzle  232  entering the diesel fill tube  204  of  FIGS. 2 and 3  along directional arrow  234 . Such nozzles typically have outer diameters of approximately 13/16 inch (approximately 21 mm), while typical #2 low-sulfur diesel nozzles have outer diameters of approximately 15/16 inch (approximately 24 mm).  FIG. 5  shows an after position  240  of the gasoline or DEF nozzle  232  of  FIG. 4  fitting loosely into the diesel fill tube  204  of  FIGS. 2 and 3 . A portion  242  of gasoline or DEF nozzle  232  is shown protruding through entrance hole  212  and into the inner tube  208 . In this configuration, gasoline or DEF nozzle  232  is positioned to supply gasoline or DEF to the diesel fuel tank (not shown) attached to inner tube  208 . 
         [0009]      FIG. 5  illustrates an incorrect fueling configuration in which the wrong type of fuel or fluid (e.g., gasoline or DEF) may be introduced to a diesel-powered vehicle. Note that in the prior art there is no physical bar to the insertion of a gasoline or DEF nozzle into the diesel fuel tube, thus the incorrect fueling operation illustrated in  FIGS. 4 and 5  is possible, and indeed, commonly occurs accidentally. As discussed above, the consequences of supplying gasoline or DEF to a diesel internal combustion engine may include serious damage to internal components of the diesel engine arising from premature explosion of the gasoline within the engine cylinders (due to the higher compression ratios compared with gasoline engines), as well as a lack of natural lubrication for engine components (diesel fuel oil is a lubricant, while gasoline is not). 
         [0010]    Various devices are known to prevent improper dispensing of fuel into the wrong container. For example, U.S. Pat. No. 7,661,550, issued to Feichtinger, discloses a filler neck of a fuel tank with an arrangement of mechanical tubes, latches, locks, and springs that allow only the correct fuel nozzle to be inserted to dispense fuel. This device discriminates between smaller and larger nozzle sizes so that only a larger nozzle for dispensing diesel fuel can be inserted and a smaller gasoline nozzle is prevented from being inserted. Other examples of mechanical methods include U.S. Pat. No. 8,863,792, issued Kataoka et al, for a filling port structure for a fuel tank, U.S. Pat. No. 8,726,950, issued to Miller et al, for a mis-fuel inhibitor, U.S. Pat. No. 8,978,913, issued to Walser et al, for a filler neck for the fuel tank of a motor vehicle with selective opening, and Printed Publication No. US 2011/0315682, to Tsiberidis, published on Dec. 29, 2011. Other prior art devices utilize electronic components to prevent improper fueling. For example, U.S. Pat. No. 8,678,049, issued to Roys et al, and U.S. Pat. No. 9,133,013, issued to Roys, both disclose indicators that alert an operator of an attempted improper fueling. 
         [0011]    Although prior art devices are known to prevent improper dispensing of fuel, such devices are overly complex, and require modification of fuel pumps or fuel tanks. Further, such complex arrangements complicate assembly, installation or retrofitting on existing systems. This makes wide spread adoption of these solutions difficult, requiring great expense. Gas stations are hesitant to modify pumps before a significant number of automobile filler tanks are modified to work with the new nozzles, and automobile manufacturers are hesitant to modify the fuel tanks until a significant number of gas stations have modified nozzles. 
         [0012]    The problem of putting the wrong fuel or fluid in a tank is not limited to a consumer filling a tank of an automobile, but can extend to workers filling fuel trucks with an incorrect fuel, or a fuel truck operator putting an incorrect fuel into an underground tank at a gas station or into an above-ground commercial or agricultural tank. For example, a worker could put gasoline in the diesel tanker truck or diesel in the gasoline tanker truck or diesel in the gasoline tanker truck. The incorrect fuel could be put into the ground holding tanks at the gas station or convenience store. As a result, hundreds of vehicles would be affected because the owner/operator of the gas pumps doesn&#39;t recognize the wrong fuel has been put in his underground storage tanks until a customer has problems and complains. 
         [0013]    What is needed is a device capable for use with current fuel tanks to prevent improper fueling without complicated mechanics, modification or expensive electronics. 
       SUMMARY OF THE INVENTION 
       [0014]    An object of the present invention is to provide a method and device to prevent incorrect fueling operations, such as putting gasoline or DEF into a diesel-powered vehicle. 
         [0015]    A device is provided to prevent the accidental introduction of an incorrect liquid into a fuel container. The device discriminates between nozzle diameters, allowing entrance of nozzle diameters at or greater than a predetermined minimum diameter while inhibiting entrance of nozzles having diameters less than the predetermined minimum diameter. The device may comprise a fuel cap assembly that can easily replace current fuel caps or covers, or the device can be permanently mounted to an opening, such as a fuel filler neck, of a fuel container, such as a fuel tank. 
         [0016]    Upon insertion of a nozzle of the appropriate diameter, locking elements are displaced, which allow the nozzle to then displaced pivoting members and enter the container opening. 
         [0017]    The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the scope of the invention as set forth in the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    For a more thorough understanding of the present invention, and advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
           [0019]      FIG. 1  is a schematic view of a prior art motor vehicle having an internal combustion engine and a fuel tank connected to the internal combustion engine; 
           [0020]      FIG. 2  is a schematic isometric view of a prior art diesel nozzle entering a diesel fill tube in the prior art; 
           [0021]      FIG. 3  is a schematic isometric view of the diesel nozzle of  FIG. 2  fitting closely into a diesel fill tube; 
           [0022]      FIG. 4  is a schematic isometric view of a prior art gasoline nozzle entering a diesel fill tube; 
           [0023]      FIG. 5  is a schematic isometric view of the gasoline nozzle of  FIG. 4  fitting loosely in a diesel fill tube; 
           [0024]      FIG. 6  is an exploded view of the fuel cap assembly according to the invention; 
           [0025]      FIG. 7  is a perspective view that illustrates the fuel cap assembly in an open position; 
           [0026]      FIG. 8  is a sectional view taken along line A-A of  FIG. 7 ; 
           [0027]      FIG. 9  is a perspective view that illustrates the body assembly with the closure mechanism and locking elements in a closed position; 
           [0028]      FIG. 10  is a top view of the body assembly of  FIG. 9 ; 
           [0029]      FIG. 11  is a sectional view of the body assembly taken along line B-B of  FIG. 12 ; 
           [0030]      FIG. 12  is a perspective view that illustrates the body assembly with the closure mechanism and locking elements in an open position; 
           [0031]      FIG. 13  is a top view of the body assembly of  FIG. 12 ; 
           [0032]      FIG. 14  is a perspective view of the fuel cap assembly before insertion of a nozzle; 
           [0033]      FIG. 15  is a sectional view taken along line C-C of  FIG. 14 ; 
           [0034]      FIG. 16  is a perspective view of the fuel cap assembly with a nozzle fully inserted; 
           [0035]      FIG. 17  is a sectional view taken along line D-D of  FIG. 16 ; 
           [0036]      FIG. 18  shows a schematic view of an embodiment of the present invention used to prevent introduction of an incorrect fuel into a tanker truck; 
           [0037]      FIG. 19  shows schematic view of an embodiment of the present invention used to prevent introduction of an incorrect fuel into an underground gas tank; and 
           [0038]      FIG. 20  is a flowchart showing a method of preventing improper fueling. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0039]    Embodiments of the invention provide an apparatus for preventing incorrect fueling operations for diesel-powered vehicles and diesel storage containers. As seen in  FIGS. 6-8 , the apparatus is shown as a removable fuel cap assembly  300  for a fuel container such as a vehicle gas tank or a fuel storage container. As used herein, the term “fuel container” is used to mean any container in which fuel is kept, including vehicle fuel tanks and stationary tank. The term includes both the portion of the container in which fuel is stored, and the portion of the container, such as a filler neck, through which fuel is supplied to the container. Fuel cap assembly  300  is constructed as a replaceable fuel cap for an existing vehicle gas tank or fuel storage container. The apparatus prevents insertion of a fuel nozzle that is smaller in diameter than the nozzles provided for the intended fuel. Although the apparatus is shown and described as a removable and replaceable fuel cap assembly  300 , the apparatus can also be incorporated into an inlet filler neck of a vehicle fuel system with an outer cap. The fuel cap assembly  300  shown and described is only one suitable arrangement in which the apparatus can be used, but is not intended to limit applications and uses of the present invention, nor the scope of the claims that follow. 
         [0040]    Fuel cap assembly  300  includes a body  302  configured to be connected to a filler neck or other opening of a fuel container (not shown), a closure mechanism  304  movable from a closed position that blocks access of the nozzle into the fuel container to an open position to allow access into the fuel container through body  302 , and a locking mechanism  306  to releasably lock closure mechanism  304  in a closed position. Together closure mechanism  304  and locking mechanism  306  make up a nozzle discriminating mechanism. A nozzle guide  308  ensures that a fuel nozzle is not inserted at an angle to accidentally release closure mechanism  304 . A cover  310  with a seal  312  is pivoted about pin  313  to close fuel cap assembly  300 . Cover  310  can be opened to provide access to the interior of body  302  ( FIGS. 7 and 8 ) and held in the open position by a spring  325  ( FIG. 7 ) or closed and held in place with a catch  326  to protect the body interior from the outside elements. Although body  302  is shown with screw threads  314  for attachment to the neck of a fuel container, fuel cap assembly  300  may be attached using any number of attachments, such as a bayonet lock, snap-on connection, or another preferred attachment. 
         [0041]    Body  302  and nozzle guide  308  provide a housing to contain closure mechanism  304  and locking mechanism  306 . Body  302  extends along a longitudinal axis  303  ( FIGS. 6 and 8 ) from a first end  302   a  forming a fuel inlet to a second end  302   b  forming a fuel outlet. A through-opening  316  ( FIG. 8 ) extends through body  302  from first end  302   a  to second end  302   b  defining a fuel flow path  305  into which a fuel nozzle of sufficient diameter can be inserted to dispense fuel into a container. Closure mechanism  304  is positioned adjacent locking mechanism  306  on a side facing second end  302   b . Body  302  includes a platform  318  and spaced longitudinally extending protrusions  320  forming gaps  322  between each protrusion  320 . Each protrusion  320  has a top surface  324  with a triangular shape that slopes toward the center of body  302 . Outer circumferential screw threads  314  are provided at second end  302   b  of body  302  for connection to the fuel container. 
         [0042]    Closure mechanism  304  is formed of multiple segments or pivotal elements  328  mounted circumferentially about the perimeter of through-opening  316 . Pivotal elements  328  extend radially inward toward the center of body  302  to block through-opening  316  when in the closed position. Each pivotal element  328  is located within a gap  322  and is pivotally connected to associated protrusions  320  by a pivot pin  330  and biased to the closed position by spring  331 . Pivotal elements  328  pivot from a closed position to an open position about pivot pins  330  each of which forms an axis extending perpendicular to longitudinal axis  303  and positioned in a plane  307  ( FIG. 8 ). 
         [0043]    Locking mechanism  306  is formed of multiple locking elements  332  extending radially inwardly. Each locking element  332  is located within a gap  322  and is pivotally connected to associated protrusions  320  by a pivot pin  334  to pivot from a locked position to an unlocked position. Each pivot pin  334  defines an axis extending perpendicular to longitudinal axis  303  and positioned in a plane ( FIG. 8 ). Plane  309  is parallel to plane  307  and positioned nearer the fuel inlet than plane  307 . Pivot pins  334  about which each locking element  332  pivots are spaced along longitudinal axis from pivot pins  330  about which each pivotal element  328  pivots in a direction toward second end  302   a  of body  302 . Pivot pin  334  of each locking element is in the same plane as the pivot pin  330  of the corresponding pivotal element, each of the planes being parallel to longitudinal axis  303 . Locking elements  332  include a radially extending upstream-facing surface  336  that slopes inwardly toward the center of body  302  and are biased to a locking position by a spring  338 . Pivotal elements  328  and locking elements  332  are arranged within gaps  322  so that each locking element  332  is associated with an adjacent pivotal element  328  to block its associated pivotal element  328  from pivoting to an open position. Each locking element  332  is positioned adjacent its associated pivotal element  328  at a side facing first end  302   a  of body  302 . Surfaces  336  of locking elements  332  form an engagement surface for a nozzle of sufficient diameter so that, when engaged by the nozzle, a force is applied to locking elements  332  causing them to pivot to an unlocking position to release pivotal elements  328 . 
         [0044]    Each pivotal element  328  includes an extension with a flange  340  that extends radially outwardly when in the closed position. Each locking element  332  includes a lip  341  positioned in an abutting relationship with a flange  340  of an associated pivotal element  328  in the closed position to hold or lock pivotal element  328  in the closed position and prevent it from pivoting to an open position. When a nozzle of sufficient diameter engages surfaces  336  of locking elements  332  a downstream directed force is applied and locking elements  332  pivot about pivot pins  334  to a first insertion point so that lip  341  disengages its associated flange  340  and is no longer in an abutting relationship therewith. As the nozzle is further inserted to a second insertion point, a further force is applied by the nozzle causing locking elements  332  to engage upper surfaces  342  of associated pivotal elements  328  causing them to pivot about pivot pins  330  inside flow path  305  and toward second end  302   a  of body  302  into an open position. Further insertion of the nozzle causes pivotal elements  328  to pivot to a fully open position to allow passage of the nozzle into through-opening  316  and establish a path between fluid inlet at first end  302   a  of body  302  and fluid outlet at second end  302   b  of body  302 . In the fully open position, each pivotal element  328  is pivoted about 90° from the closed position so that a surface  343  facing second end  302   b  of body  302  in the closed position is substantially parallel with an inner surface  345  of body  302  ( FIGS. 11 and 17 ). 
         [0045]    In the closed position shown in  FIGS. 8-10 , locking elements  332  form an opening having a diameter D ( FIG. 10 ) so that only nozzles of sufficient diameter larger than diameter D engage faces  336  of locking elements  332  to pivot them to release pivotal elements  328  from the locked position. Pivotal elements  328  extend radially inward further than locking elements  332  so that further insertion of the nozzle causes locking elements  332  to engage upper surfaces  342  of pivotal elements  328  to be pivoted to the open position to dispense fuel through body  302  and into the fuel container ( FIG. 17 ). In the open position shown in  FIGS. 11-13 , locking elements  332  are shown pivoted a position in which lips  341  of locking elements  332  no longer abut flanges  340  of associated pivotal elements  328  and release them to be pivoted to a fully open position allowing access to through-opening  316   
         [0046]    When the nozzle is withdrawn, springs  338  bias locking elements  332  back to the locking position in which lip  341  of each locking element  332  engages flange  340  of its associated pivotal element  328  to force pivotal elements  328  into the closed position and hold or lock them in the closed position. 
         [0047]    However, a nozzle for an inappropriate fuel (i.e., smaller diameter nozzle for gasoline) having a diameter less than diameter D will pass through locking elements  332  without engaging faces  336  of locking elements  332 . The nozzle will then abut upper surfaces  342  of pivotal elements  328  which are held closed by the abutting relationship between lip  341  of locking elements  332  and flange  340  of an associated pivotal element  328  to block access to the fuel inlet opening  316 . Protrusions  320  form an opening slightly larger than diameter D so as not to block the nozzle and prevent insertion. 
         [0048]    It is understood that pivotal elements  328  and locking elements  332  may be interchanged with pivotal elements and locking elements with dimensions that differ from that shown in the figures to accommodate nozzles of varying diameters. 
         [0049]      FIGS. 14 and 15  show cap assembly  300  with a nozzle  344  positioned for insertion to dispense fuel. Nozzle guide  308  has an opening  346  to allow nozzle insertion substantially longitudinally to prevent nozzle  344  from being inserted at an angle and accidentally release pivotal elements  328 . It can be clearly seen that locking elements  332  prevent pivotal elements  328  from pivoting should a nozzle of insufficient diameter be inserted to push against pivotal elements  328 .  FIGS. 16 and 17  show nozzle  344  fully inserted in opening  316  with pivotal elements  328  and locking elements  332  in the fully open position. 
         [0050]    While the embodiments described are used to prevent introduction of gasoline into the tank of a diesel automobile, the invention is not limited to any particular type of tank or any particular type of liquid being pumped. For example, the invention may be incorporated into different types of tanker transport trucks, above ground and below ground fuel storage tanks, railroad tankers that transport fuel, and fuel storage tanks used to transport fuel on ships. 
         [0051]    In one example,  FIG. 18  shows schematically the use of an embodiment of the invention to prevent the introduction of an incorrect fuel from a supply tank  1302  at a fuel storage facility into a tanker truck  1304 . A fuel inlet  1306  on the truck includes an insert  1308  embodying the invention to prevent a nozzle  1310  from being inserted into a fuel truck if the fuel in tank  1302  is not the type of fuel intended to be introduced into fuel truck  1304 . Of course, the type of nozzle  1310  at the storage facility will typically be of a different design from the nozzle at a retail gas station, so the design of the insert  1308  at the fuel inlet  1306  of the tanker truck  1304  will be modified accordingly. 
         [0052]    In another example,  FIG. 19  shows schematically the use of an embodiment of the invention to prevent the introduction of an incorrect fuel from a tanker truck  1304  into an underground or other storage tank  1402  at a gas station, commercial fueling station, agricultural fueling station, or heating oil storage. Tanker truck  1304  dispenses fuel through nozzle  1404  into an inlet  1406  of underground tank  1402 . An insert  1408  in accordance with the present invention in the inlet  1406  prevents introduction of an incorrect fuel into the tank  1402 . While tank  1402  is shown under ground level  1410 , tank  1402  could also be above ground. Of course, the type of nozzle  1404  used by tanker will be different from the nozzle used to fill cars at a retail gas station, so the design of the insert  1408  at the filler inlet  1406  of the tank will be modified accordingly. 
         [0053]    It can be seen from the following drawings that only a nozzle of sufficient diameter can push the locking segments into the release position and that a nozzle of smaller diameter would simply go through and past the locking mechanisms. Any attempt to insert a small diameter nozzle past the gate segments is prevented because they are blocked from pivoting to the open position by the locking segments. The invention is not limited to use in preventing incorrect fueling operation, but can be used whenever it is desirable to require a first part minimum size to be inserted into an opening in a second part. 
         [0054]      FIG. 20  is a flowchart showing steps for preventing improper fueling. In step  2002 , entails providing multiple pivoting elements to blocking a fuel nozzle path in a nozzle path. Step  2004  entails providing multiple locking elements in the fuel nozzle path, each of the locking elements associated with one of the multiple pivoting elements, the locking element biased to a locking position that prevents the pivoting element from pivoting out of the fuel nozzle path. Step  2006  entails inserting into the fuel nozzle path a fueling nozzle having a diameter sufficiently large to displace the multiple locking elements to allow the multiple pivoting elements to pivot and unblock the nozzle path. 
         [0055]    In some embodiments, inserting a fueling nozzle having a diameter sufficiently large to displace the multiple locking elements comprises inserting a fueling nozzle that pivots each of the multiple locking elements along a corresponding locking element pivot axis and pivots each of the multiple pivoting elements along a corresponding pivoting element pivot axis, the pivot axes for a corresponding pivot element and locking element being parallel to each other and displaced from each other along a fuel nozzle path. 
         [0056]    Some embodiments provide an apparatus to prevent introduction of incorrect fuel into a fuel container, comprising: 
         [0057]    a housing having a first end, a second end, a fluid inlet located at the first end, a fluid outlet located at the second end, and a flow path that extends through the housing from the fluid inlet to the fluid outlet; 
         [0058]    a nozzle discriminating mechanism coupled to the housing, the nozzle discriminating mechanism comprising a plurality of pivotable elements mounted circumferentially about a perimeter of a first plane perpendicular to of the flow path and configured to pivot inside the flow path, wherein: 
         [0059]    the nozzle discriminating mechanism is switchable between a locked state, in which the plurality of pivotable elements are locked into a configuration that obstructs the fluid inlet, and an unlocked state, in which the plurality of pivotable elements are capable of pivoting inside the flow path and toward the second end of the housing, and 
         [0060]    the nozzle discriminating mechanism is configured to switch from the locked state to the unlocked state when a nozzle having a first diameter is inserted into the fluid inlet port, and to remain in the locked state when a nozzle having a second diameter smaller than the first diameter is inserted into the fluid inlet port. 
         [0061]    In some embodiments, the nozzle discriminating mechanism further comprises a plurality of locking elements disposed about a second perimeter of a second cross-section of the flow path, the second cross-section disposed upstream of and adjacent to the first cross-section; 
         [0062]    switching of the nozzle discriminating mechanism from the unlocked state to the locked state comprises each of the locking elements interlocking with one of the pivotable elements such that each pivotable element cannot pivot and is locked into a fixed orientation relative to the housing; and 
         [0063]    when each of the pivotable elements has been locked into a fixed orientation, the pivotable elements collectively form a surface that obstructs the fluid inlet port. 
         [0064]    In some embodiments, the pivotable elements and the locking elements extend radially inward, in a direction from the perimeter of the first cross-section towards the point where the longitudinal axis of the flow path intersects the first cross-section, when the pivotable elements are locked into the fixed orientation by the locking elements. 
         [0065]    In some embodiments, the pivotable elements extend radially inward further than the locking elements. 
         [0066]    In some embodiments, the locking elements and the pivotable elements are configured such that insertion of a nozzle having the first diameter into the fluid inlet up to a first insertion point along the flow path causes the locking elements to disengage the pivotable elements. 
         [0067]    In some embodiments, the locking elements and the pivotable elements are configured such that insertion of a nozzle having the first diameter into the fluid inlet up to a second insertion point, the second insertion point being a location along the flow path that is further downstream than the first insertion point, causes a force to be exerted on each of the pivotable elements that causes the pivotable elements to pivot such that pivotable elements are oriented in a in a configuration that establishes a nozzle path between the fluid inlet and the fluid outlet. 
         [0068]    In some embodiments, the apparatus is configured such that insertion of a nozzle having the first diameter into the fluid inlet port causes the nozzle having the first diameter to apply a force to upstream-facing surfaces of the locking elements in the downstream direction. 
         [0069]    In some embodiments, the configuration that establishes a nozzle path between the fluid inlet and the fluid outlet comprises: 
         [0070]    each of the pivotable elements being oriented in a direction parallel to an interior surface of the housing shared with the flow path, and 
         [0071]    a surface of each pivotable element facing downstream when the pivotable elements were arranged in the configuration that obstructs the fluid inlet is adjacent to and flush with the interior surface to which the pivotable element is parallel. 
         [0072]    Some embodiments further comprise biasing elements configured to bias the pivotable elements, the locking elements, or the pivotable elements and the locking elements in favor of the configuration that obstructs the fluid inlet port such that removal of a nozzle having the first diameter from the fluid inlet port causes the nozzle discriminating mechanism to switch to the unlocked state to the locked state. 
         [0073]    In some embodiments, the biasing elements comprise springs. 
         [0074]    Some embodiments further comprise a screw threaded outer circumferential surface of the second end, the screw threading configured such that the second end can be rotated into the inlet of the fuel container and fixedly engaged with a complementary screw threaded inner circumferential surface of the inlet of the fuel vessel. 
         [0075]    Some embodiments further comprise a screw threaded inner circumferential surface of the second end, the screw threading configured such that the second end can be rotated onto and around a screw threaded outer circumferential surface of the inlet of the fuel vessel to fixedly engage the second end with the inlet of the fuel vessel. 
         [0076]    In some embodiments, the first diameter is a standard diameter for first nozzles designed to supply a first type of fuel to a fuel vessel. 
         [0077]    In some embodiments, the second diameter is a standard diameter of second nozzles designed to supply a second type of fuel to a fuel vessel. 
         [0078]    In some embodiments, the first nozzles are nozzles designed to deliver the first type of fuel to fuel tanks of automobiles compatible with the first type of fuel, and the second nozzles are nozzles designed to deliver the second type of fuel to fuel tanks of automobiles compatible with the second type of fuel. 
         [0079]    In some embodiments, the first type of fuel is diesel fuel, and the second type of fuel is gasoline. 
         [0080]    In some embodiments, components of the fuel cap comprise materials that are chemically resistant to the first type of fuel and the second type of fuel. 
         [0081]    In some embodiments: 
         [0082]    the pivotable elements are first pivotable elements, and the locking elements are first locking elements; 
         [0083]    the first pivotable elements and the first locking elements are interchangeable with second pivotable elements and second locking elements; and 
         [0084]    dimensions of the second pivotable elements and the second locking elements are such that, if the second pivotable elements and the second locking elements are interchanged with the first pivotable elements and the first locking elements, the nozzle discriminating mechanism will switch from the locked state to the unlocked state when a nozzle having a third diameter different from the first diameter is inserted into the fluid inlet, and to remain in the locked state when a nozzle having a fourth diameter that is smaller than the third diameter is inserted into the fluid inlet. 
         [0085]    In some embodiments, the third diameter is a standard diameter for third nozzles designed to supply a third type of fuel to a fuel vessels designed to hold the third type of fuel, and further comprising a sleeve coupling adapted to: 
         [0086]    connect the second end of the housing to an inlet that is incompatible with coupling directly to the second end and that provides access to an interior chamber of a fuel vessel designed to hold the third type of fuel; and 
         [0087]    establish fluid communication between a third nozzle inserted into the fluid inlet port, the flow path of the housing, and the interior chamber of the fuel vessel designed to hold the third type of fuel. 
         [0088]    In some embodiments, the inlet is a filler neck and the fuel vessel is a diesel fuel container. 
         [0089]    Some embodiments provide a cap assembly for attachment to a filler neck of a fuel container, comprising: 
         [0090]    a body having a longitudinal axis with a through-hole extending from one end of the body to a second end of the body for access to an interior of the fuel container; 
         [0091]    multiple radially inward extending pivotable elements disposed about a periphery of the through-hole, each pivotable element being pivotally mounted about an axis perpendicular to the longitudinal axis of the body to block access to the interior of the fuel container in a closed position and to allow access to the interior of the fuel container in an open position; and 
         [0092]    a displaceable locking member associated with each pivotable element and located about the periphery of the through-hole, each locking member positioned adjacent an associated pivotable element on a side toward a first end of the body, each locking member extending radially inward and pivotable about an axis perpendicular to the longitudinal axis of the body to be movable between a locked configuration that prevents the pivotable element from pivoting to the open position and an unlocked configuration that allows the pivotable element to pivot to the open position for access to the interior of the fuel container. 
         [0093]    In some embodiments, the axis about which each pivotable element rotates is longitudinally spaced from the axis about which its associated locking member rotates. 
         [0094]    In some embodiments, each locking member is spring biased into an abutting relationship with its associated pivotable element in the locked configuration. 
         [0095]    In some embodiments, each pivotable element comprises a flange that extends radially outward in a direction away from the longitudinal axis, and each locking member includes a lip positioned in an abutting relationship with the flange of the pivotable element in the locked configuration and positioned in a non-abutting relationship with the radially outward flange of its associated pivotable element in the unlocked configuration. 
         [0096]    In some embodiments, each locking member includes a surface for engagement with a nozzle of sufficient diameter to move each locking member to the unlocked configuration to release its associated pivotable element to be movable into the open position and allow the nozzle to be inserted into the through-hole. 
         [0097]    Some embodiments provide an apparatus for preventing a first type of fuel from entering a vessel containing a second type of fuel, comprising: 
         [0098]    a body having an upstream end, a downstream end, and a through-hole that passes through the body along a longitudinal axis from an opening in the body at the upstream end to an opening in the body at the downstream end; 
         [0099]    a plurality of pivotable elements disposed about and pivotally connected to an upstream portion of the body that defines an outer boundary of the through-hole, the plurality of pivotable elements configurable in an open configuration and a closed configuration, wherein: 
         [0100]    the closed configuration comprises each of the pivotable elements being extended radially inward toward the longitudinal axis such that the pivotable elements collectively form a surface across the through-hole that blocks the through-hole; 
         [0101]    each pivotable element is pivotally connected to the body about an axis perpendicular to the longitudinal axis of the body and switching from the closed configuration to the open configuration comprises each of the pivotable elements pivoting away from the longitudinal axis in a direction that causes unblocking of the through-hole; and 
         [0102]    a displaceable locking member associated with each pivotable element, the displaceable locking member supported by a portion of the body that is adjacent to and upstream of the associated pivotable element, wherein: 
         [0103]    each displaceable locking member extends radially inward toward the longitudinal axis when the plurality of pivotable elements are in the closed configuration and locks the orientation of the adjacent pivotable element such that the plurality of pivotable elements continuously maintain the closed configuration that causes blocking of the through-hole, 
         [0104]    each displaceable locking member is movable about an axis that is tangent to the portion of the body that supports the displaceable locking member and that lies in the plane of a cross-section of the through-hole that is normal to the longitudinal axis, and 
         [0105]    movement of the displaceable locking member unlocks the associated pivotable element and enables the pivotable element to pivot to the open position. 
         [0106]    In some embodiments, the axis about which each pivotable element rotates is longitudinally spaced from the axis about which its associated displaceable locking member rotates. 
         [0107]    In some embodiments, each displaceable locking member is spring biased into an abutting relationship with its associated pivoting member in the locked orientation. 
         [0108]    In some embodiments: 
         [0109]    each pivotable element comprises a radially outward flange; 
         [0110]    each displaceable locking member comprises a lip; 
         [0111]    abutment of the radially outward flange of each pivotable element by the lip of the associated displaceable locking member locks the orientation of the pivotable element; and 
         [0112]    moving the lip of each displaceable locking member out of an abutting relationship with the associated pivotable member unlocks the orientation of the pivotable element. 
         [0113]    In some embodiments, the diesel fuel container is a fuel tank of a vehicle, a fuel storage container, or a tanker vehicle. 
         [0114]    In some embodiments, each displaceable locking member includes a surface configured to engage a nozzle of sufficient diameter to move each displaceable locking member to the unlocked configuration to release its associated pivotable element to be movable into the open position and allow the nozzle to be inserted into the through-hole. 
         [0115]    Some embodiments provide an apparatus for a filler neck of a diesel fuel container to prevent gasoline from entering the diesel fuel container, comprising: 
         [0116]    a body having a longitudinal axis with a through-hole for access to an interior of the diesel fuel container; 
         [0117]    at least one closure element extending radially inwardly to block access to the through-hole in a closed position, the closure element pivotally connected to the body about an axis perpendicular to the longitudinal axis of the body to pivot to allow access to the through hole in an open position; and 
         [0118]    at least one displaceable locking member associated with the closure element to lock the closure element in the closed position, and pivotally connected to the body about an axis perpendicular to the longitudinal axis of the body to allow the closure element to pivot to the open position. 
         [0119]    Some embodiments provide an apparatus for preventing incorrect fueling operations, comprising: 
         [0120]    a housing defining a nozzle path; 
         [0121]    a set of pivoting elements, each of the pivoting elements having a pivoting element pivot pin positioned along the periphery of the nozzle path, the pivoting allowing the pivoting element to pivot out of the nozzle path; and 
         [0122]    a set of locking elements, each of the locking elements associated with one of the pivoting elements, the locking elements each having a locking element pivot pin and extending sufficiently into the nozzle path so that a nozzle of a sufficiently large diameter inserted into the nozzle path will displace all of the locking elements in the set, allowing the pivoting elements to pivot to pass the nozzle. 
         [0123]    Some embodiments further comprise a set of biasing elements, each of the biasing elements associated with one of the locking elements and maintaining the associated locking element in a position to prevent the pivoting element from pivoting out of the nozzle path unless each of the locking elements is displaced by a nozzle of sufficiently large diameter. 
         [0124]    In some embodiments, all of the locking element pivot pins are in a first plane and all the of the pivoting element pivot pins are in a second plane. 
         [0125]    Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made to the embodiments described herein without departing from the scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.