Patent Publication Number: US-2006016813-A1

Title: Safety improvement for a fuel tank

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      Not Applicable  
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
      Not Applicable  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates generally to fuel tanks, such as are currently in use with automobiles. More particularly, this invention relates to a safety improvement in these tanks which reduces the risk of fire and explosion of the tank when the vehicle is involved in a collision.  
      2. Description of the Prior Art  
      Recently fuel tanks installed in automobiles have shown a tendency to lose their structural integrity when the vehicle is involved in a collision, allowing dangerous leakage of fuel and fuel vapor. This leakage is due in part to cracks or breaks in the wall of the tank and due in part to the separation of the fuel line attachment cover from the tank wall. Regardless of the source of the leakage, a catastrophic fire and explosion is often the result.  
      Prior art explosion suppression apparatus has included the use of a metallic mesh insert, as described in U.S. Pat. No. 6,604,644 and U.S. Pat. No. 6,415,942. Such systems effectively suppress explosion when an un-ruptured tank is in contact with a fire, but they do not inhibit the spilling of fuel from a tank rupture or the venting of fuel vapor. Consequently, the risk of fire and explosion still persists with prior art tanks.  
     SUMMARY OF THE INVENTION  
      It is accordingly the principal object of this invention to improve the safety of vehicle fuel tanks and reduce the risk of fire or explosion when a vehicle is involved in a collision.  
      This and other objects are accomplished by covering the tank exterior with a sleeve of fuel and vapor impervious material. Preferably, before the application of the sleeve, the fuel line attachment cover is secured against collision caused detachment from the tank by the addition of fastening screws. In a further aspect of the invention, a filler of metallic mesh is placed within the tank such that it substantially fills the interior of the tank and serves to suppress explosion.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a perspective view of a stock prior art automobile fuel tank depicting its metal wall enclosure, the fuel line, and the fuel line attachment cover.  
       FIG. 2  is a perspective view of the stock automobile fuel tank of  FIG. 1  depicting the removal of the fuel line and the fuel line attachment cover.  
       FIG. 3  is a perspective view of the automobile fuel tank of  FIG. 2  showing the reattachment of the fuel line attachment cover with additional fastening screws.  
       FIG. 4  is a perspective view of a portion of a sheet of expanded metallic foil for use as the mesh filler insert within the tank.  
       FIG. 5  is a perspective view, shown partially cut away, of the improved tank of the present invention showing filler packets of metallic foil mesh within the tank and showing a sleeve applied around the tank exterior.  
       FIG. 6  is a perspective view, shown partially cut away, of the improved tank of the present invention showing a filler of metallic foil mesh within the tank and showing a sleeve applied around the tank exterior. 
    
    
      While the invention will be described in connection with a preferred embodiment, it will be understood that it is not the intent to limit the invention to that embodiment. On the contrary, it is the intent to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.  
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Turning first to  FIG. 1  there is shown a prior art fuel tank  10  comprised of an enclosure wall  12 , typically of a metal composition. Also shown is a fuel line  14 , affixed to the tank enclosure  12  by means of a fuel line attachment cover  16 . This prior art fuel line attachment cover  16  is typically affixed to the tank enclosure  12  by screws  18 .  
      According to one aspect of the present invention, the fuel line  14  and the fuel line attachment cover  16  of the prior art fuel tank are first removed, as depicted in  FIG. 2 , and then reinstalled, as shown in  FIG. 3 . During the reinstallation of the attachment cover, additional fastening means is applied, such as additional screws  20 , or the like, to further secure the cover  16  and thereby prevent detachment during a collision.  
      In another aspect of the present invention, a filler for the tank is formed from one or more sheets of expanded metallic sheet  30 , a portion of which is shown in  FIG. 4 . These metallic sheets are preferably an aluminum mesh and are now well known in the art as an explosion suppressing filler for tanks of combustible fuel (See for example U.S. Pat. No. 6,604,644 and U.S. Pat. No. 6,415,942). These mesh sheets may be formed into packets  35 , as described in U.S. Pat. No. 6,604,644, and then inserted into a tank (see  FIG. 5 ) to substantially fill the interior of the tank. Alternatively, as shown in  FIG. 6 , the mesh sheet may be folded, rolled, or otherwise formed to provide a filler  36  of metallic mesh which substantially fills the tank.  
      In a further aspect of this invention, the tank is covered with a sleeve  40  of material which is substantially impervious to liquid fuel and fuel vapor (see  FIGS. 5 and 6 ). This sleeve covers the entire tank enclosure  12  and substantially seals the tank to prevent passage of liquid fuel or fuel vapor which may leak from the tank through any crack or opening caused by a collision. This sleeve is preferably formed from a fire resistant thermoplastic material and may be applied to the tank exterior with substantial effect independent of the other improvements discussed herein.  
      The above described tank modification has been directed toward new stock tanks, prior to installation in a vehicle. When a used tank from a vehicle is being modified as herein described, the tank is first removed from the vehicle and drained of fuel prior to modification. It is then modified as above described and reinstalled into the vehicle.  
      From the foregoing description, it will be apparent that modifications can be made to the apparatus and method for using same without departing from the teachings of the present invention. Accordingly, the scope of the invention is only to be limited as necessitated by the accompanying claims.