Abstract:
A method and system for preventing vehicle misfuelling by utilizing an apparatus that receives a fuel nozzle into the filler neck, and activates a vacuum on the nozzle inserted therein. Using the pump&#39;s internal shut-off mechanism, this prevents the fuel pump from dispensing fuel until the sensing unit within the apparatus is able to identify the fuel proposed to be added to the tank. If the fuel is deemed acceptable, the vacuum is released, and the fuel is permitted to enter into the desired fuel tank.

Description:
This application is a divisional application of U.S. application Ser. No. 10/140,686 filed May 7, 2002, now U.S. Pat. No. 6,712,102. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a method and system of preventing the addition of the wrong type of fuel to a fuel tank, by monitoring the vapor pressure of the fuel being added, and if detected as the incorrect fuel, shutting off the supply by activating the fuel pump&#39;s shutoff via maintaining a vacuum on the fuel nozzle or by inducing increased back pressure in the fuel tank. 
   Because of differing types of fuel being offered at filling stations, it is frequent that the wrong type of fuel will be added to a vehicle&#39;s tank. Particularly troublesome is the confusion between diesel and gasoline fuels, which because of their chemical properties, are not interchangeable. Furthermore, the addition of the wrong type of fuel will not only fail to power the vehicle, but also exposes the engine to the possibility of serious damage. 
   Various methods have been implemented to prevent the confusion of the fuels, including the manufacture of diesel fuel nozzles and filler necks being a larger diameter than their gasoline counterparts. This works relatively well for automotive use, since the fuel aperture in gasoline-powered cars are intentionally narrower as to prevent the introduction of a diesel nozzle into the filler neck. However, the converse is not true. Diesel filler necks readily accept the smaller gasoline filler nozzle, and so without proper attention, large amounts of money can be lost on an oversight when the wrong fuel is added to an engine and causes is to malfunction, or in some cases, to injure those who may be in the proximity. 
   The present invention alleviates this problem by effectively preventing the addition of any type of fuel that can be identified by vapor pressure from being added to a properly equipped fuel tank. Additionally, having such a device capable of being retrofitted to current vehicles enables end users to equip their own vehicles, rather than relying upon filling stations to retrofit their pumps with a similar system. 
   OBJECTS AND SUMMARY OF THE INVENTION 
   One objective of this invention is to provide a device that identifies a fuel by a predetermined physical or chemical characteristic and then selectively maintain a vacuum and/or controls a valve to prevent the addition of an undesired fuel to a fuel tank. 
   Another objective of this invention is to identify a fuel by a predetermined physical or chemical characteristic, and to increase the back pressure in a fuel tank to engage the fuel pump&#39;s internal shut-off if the fuel being added does not match the specified fuel to be added to the tank. 
   Still another objective of this invention is to fill a long felt need in the art for such devices, since as far as is known, there is no such device or method for automatically preventing the addition of incorrect fuel based on a receiving-side monitoring system. 
   Still another objective of the invention is to provide a method to prevent the addition of any fuel not matching the appropriate predetermined physical or chemical characteristic by applying a vacuum to a fuel nozzle or increasing back pressure inside the fuel tank, thus engaging the fuel pump&#39;s automatic shut-off. 
   Other objects and advantages of this invention shall become apparent from the ensuing descriptions of the invention. 
   According to the present invention, the apparatus receives a fuel nozzle into the filler neck, and activates a vacuum on the nozzle inserted therein. Using the pump&#39;s internal shut-off mechanism, this prevents the fuel pump from dispensing fuel until the sensing unit within the apparatus is able to identify the fuel proposed to be added to the tank. If the fuel is deemed acceptable, the vacuum is released, and the fuel is permitted to enter into the desired fuel tank. 

   
     DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings illustrate a preferred embodiment of this invention. However, it is to be understood that this embodiment is intended to be neither exhaustive, nor limiting of the invention. They are but examples of some of the forms in which the invention may be practiced. 
       FIG. 1A  shows cutaway view of the fuel detection assembly. 
       FIG. 1B  shows a front view of the valve screen in FIG.  1 A. 
       FIG. 2  shows a landscape view of a vehicle being fuelled. 
       FIG. 3  shows a front view of the control panel and switches for the detection unit. 
       FIG. 4  shows a cutaway view of an alternate embodiment of the fuel detection assembly. 
       FIG. 5  shows an enlarged view of insert  5  illustrated in FIG.  4 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Without any intent to limit the scope of this invention, reference is made to the figures in describing the preferred embodiments of the invention. Referring to  FIGS. 1 and 2 , apparatus  300  is used to sense the type of fuel being added to fuel tank  106 . Fuel tank  106  can be one of many types, such as that of a motor vehicle, aircraft, spacecraft, watercraft, free standing tank or any other vessel used to store fuel. Fuel  105  can be gasoline, diesel, aviation fuel, rocket fuel, or any other type of fuel. Apparatus  300  comprises filler neck  302 , where most of the device&#39;s components are located. Within filler neck  302  is chamber  304 , forming cavity  308  between filler neck  302  and chamber  304 . At one end of chamber  304  is valve  303  which can prevent any fuel  105  or liquid from entering fuel tank  106  when closed. The valve  303  can be operated by any number of devices, such as solenoid  312 . A short distance toward the inside of chamber  304  beyond valve  303  is valve screen  307 , shown in greater detail in FIG.  1 B. At the opposite end of chamber  304  is the fuel nozzle aperture  305 , which contains door  313 , on which is mounted switch  314 . A short distance down chamber  304  from fuel nozzle aperture  305  is gasket  306 . There is also fluid passageway  309  which connects chamber  304  to cavity  308 . Within fluid passageway  309  is sensing unit  310  and vacuum pump  311 . 
   Sensing unit  310  can be any type of sensor, detector, catalyst or the like, which could be used to identify fuel  105  and relay data used to operate apparatus  300 . A commercially available example of one such sensor is the Figaro TGS 813, which is capable of measuring fuel  105  vapor pressure. Another example is the Delphian Catalytic Bead Sensor, which can be employed to detect the upper or lower explosion limits of fuel  105  by measuring the exothermic energy produced by fuel  105  when it comes in contact with a catalyst. Further examples of possible sensors are infrared detectors which identify fuel  105  by passing infrared light through fuel  105 , or various catalytic reactions that permit the identification of fuels. 
   Referring to  FIG. 3 , an alarm unit  401  can also be employed in conjunction with apparatus  300 . Alarm unit  401  can be connected to sensing unit  310 , vacuum pump  311 , solenoid  312 , and valve  303 , depending on the selected configuration. Alarm unit  401  can have various indicators and/or alarms, such as an operating indicator  402 , alarm indicator  403 , reset switch  404 , test switch  405  and audible alarm  406 . 
   In operation, fuel nozzle  111  is inserted into fuel nozzle aperture  305  opening door  313  and is inserted into gasket  306 , which creates a seal around fuel nozzle  111 . Once door  313  is opened, switch  314  activates vacuum pump  311  and closes valve  303 . The seal created by gasket  306  and valve  303  encloses chamber  304  and when vacuum pump  311  is turned on, a vacuum is created within chamber  304 . Generally, fuel pumps  112  are configured to shut off automatically once fuel tank  106  is full, by detecting when fuel  105  covers detection hole  113  on fuel nozzle  111 . Once this occurs, fuel pump  112  ceases dispensing fuel  105 . Using this concept, the vacuum created in chamber  304  achieves the same result as fuel  105  covering detection hole  113 , and thus causes fuel pump  112  to shut off in a similar fashion. 
   Once fuel nozzle  111  is inserted into chamber  304 , sensing unit  310  will be able to detect the type of fuel  105  that is being dispensed, and make a logical determination whether to open valve  303  and turn off vacuum pump  311 , thus permitting fuel  105  to enter fuel tank  106 . Alternately, sensing unit  310  can make the determination that fuel  105  is inappropriate, and leave valve  303  closed and keep vacuum pump  311  on to prevent any fuel from entering fuel tank  106 . Audible alarm  406  can also be activated with alarm indicator  403  if so configured to indicate to the user that fuel  105  is incorrect. 
   Referring to  FIG. 4 , another embodiment, there is apparatus  100  for sensing the type of fuel being added to a fuel tank is illustrated comprising vent tube  101  which runs from the atmosphere to fuel tank  106 . Vent tube  101  also has valve  102  integrated with it whose open or closed position can be controlled by actuator  103 . 
   Actuator  103  is connected or otherwise maintains communication with sensing unit  104  which can be used to measure the vapor pressure of fuel  105  being added to fuel tank  106 . Actuator can be any device capable of adjusting the position of valve  102 , such as solenoid  312 . 
   Additional components can be added to increase the efficiency of apparatus  100 , such as surge protector  108 , which aid in preventing splashing back of fuel  105  onto sensing unit  104 . Alternately, or in combination, deflector  114  can also be used for this task. 
   As indicated above, referring to  FIG. 3 , an alarm unit  401  can also be employed in conjunction with apparatus  100 . 
   In operation, filler nozzle  111  is inserted into filler neck  110  in order to fill fuel tank  106 . As fuel  105  is being dispensed, sensing unit  104  detects the identity of fuel  105  and determines if it is the proper fuel to be added to fuel tank  106 . If it is determined to be the correct fuel, no action is taken. If, however, the fuel is determined to be the wrong fuel, sensing unit  104  will either directly or through any type of logical control, close valve  102 . This can be accomplished using the aforementioned solenoid  107 . Once valve  102  is closed, vent tube  101  is no longer vented to the atmosphere, and vapor pressure within fuel tank  106  increases rapidly, which activates the fuel pump&#39;s  112  internal shut off mechanism. This mechanism is already in place in most fuel pumps  112 , as this measurement of vapor pressure is what indicates the fuel tank is full. In the present invention, fuel pump  112  is “tricked” into believing fuel tank  106  is full, thereby cutting off fuel  105  flow. 
   Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims.