Abstract:
A combination fuel tank and cab floor for a truck tractor utilizes a deck plate over a multi-reservoir base pan. The pan is configured both to divide the fuel storage area and to provide a frame for supporting seats and bunks to be installed on the floor.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The invention relates to motor vehicle fuel storage systems and more particularly to a fuel tank directed to reducing fuel starvation and sloshing problems.  
         [0003]     2. Description of the Problem  
         [0004]     Over the road truck tractors have conventionally carried their fuel supply in two cylindrical tanks which are hung, one each, to the outside of the vehicle frame, low on the vehicles&#39; frame rails. This arrangement is referred to as a dual draw tank system. Dual draw tank systems present a number of problems relating to fuel delivery to the vehicle&#39;s engine and to vehicle stability.  
         [0005]     The use of dual draw tanks can result in uneven fuel draw into the engine since each tank is drawn from independently. Uneven fuel draw can result in differences in the fuel levels in the tanks. Differing fuel levels in the tanks usually means that the tractor is differentially loaded from side to side and this can affect cornering stability. The difference in fuel level may be difficult to ascertain as well. Also, as the tanks are drained, the fuel remaining in the tanks becomes prone to sloshing back and forth, which can affect stopping and acceleration, ride and handling performance. Fuel sloshing has in the past been partially dealt with by incorporating baffles in the fuel tank.  
         [0006]     Cylindrical fuel tanks are, despite various efforts to correct the problem, prone to rotation. This may stem over the long term from vehicle vibration. Tank rotation can require expensive repair. Cylindrical fuel tanks have not been consistently located on trucks, resulting in the need to provide numerous alternative support arrangements for other equipment on truck tractors, such as battery boxes and tool boxes.  
       SUMMARY OF THE INVENTION  
       [0007]     According to the invention there is provided a vehicle substructure comprising a floor section and a support frame disposed beneath and adjacent to the floor section, the support frame including a stamping having a raised, rectangular perimeter wall with an upper edge in contact with the floor section and a plurality of support ribs within the raised, rectangular perimeter wall each of which are orthogonal with respect to a side thereof. Reservoirs are formed in the stamping between and defined by the ribs, the raised, rectangular perimeter wall and a base from which the raised, rectangular perimeter wall and the ribs rise. Channels are located through the dikes to interconnect the reservoirs into a single fuel tank.  
         [0008]     Additional effects, features and advantages will be apparent in the written description that follows. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:  
         [0010]      FIG. 1  is a perspective view in partial cutaway of a truck tractor with an integrated cab floor fuel tank.  
         [0011]      FIG. 2  is a perspective view of the cab floor fuel tank of the present invention.  
         [0012]     FIGS.  3 A-B illustrate fuel tank pan for the integrated cab floor fuel tank.  
         [0013]      FIG. 4  is a perspective view of the edge rim of the cab floor fuel tank pan of  FIG. 3 .  
         [0014]      FIG. 5  is a front cab mount support point from the pan.  
         [0015]      FIG. 6  is a perspective view of a reinforcement bracket undergirding a pan dike.  
         [0016]      FIG. 7  is a exploded view of a foam filler and pan reservoir combination.  
         [0017]      FIG. 8  is a perspective view of a pan drain.  
         [0018]      FIG. 9  is a perspective view of a channel defined by a pan dike and an exterior perimeter wall.  
         [0019]      FIG. 10  is a perspective view of a cab side illustrating positioning of the cab floor fuel tank of the invention.  
         [0020]      FIGS. 11 and 12  illustrate substitution of the cab floor fuel tank for a tractor modesty panel.  
         [0021]      FIG. 13  is a side elevation of suspensions for a cab floor fuel tank and a driver seat mounted on the cab floor fuel tank. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0022]     Referring now to the figures and in particular to  FIG. 1 , a tractor  10  is illustrated incorporating the integrated cab floor fuel tank  18  of the invention. Tractor  10  is constructed on two longitudinally aligned frame rails  12  and  13 . Integrated cab floor fuel tank  18  is disposed between the remainder of cab  15  and the frame rails  12  and  13 . Cab  15  is defined by a passenger side side wall  16 , a forward dash panel  60 , a driver side side wall  50 , a back wall  17 , a roof  14  and integrated cab floor fuel tank  18  located at the bottom of the cab. Cab floor fuel tank  18  supports several features of the cab including driver and passenger seats  42  and  44 , and a rear bunk  20 , all of which are mounted to the cab floor fuel tank.  
         [0023]     Integrated cab floor and fuel tank  18  is illustrated in isolation in  FIG. 2 . Cab floor/fuel tank  18  comprises a floor section or deck  22  and a pan  24 . Deck  22  provides the upper portion of cab floor/fuel tank  18  and has an upper surface exposed to the truck interior on which vehicle occupants can walk and which faces the supports for objects such as seats and bunks. Support and attachment points  28  are provided distributed around the deck  22 . In a normal application deck  22  is generally rectangular. A opening  34  is provided through deck  22  toward the forward edge of the deck, allowing access to a void  32 . Void  32  is intended to provide space for installation of a transmission linkage if required for a vehicle with a manual transmission.  
         [0024]     The lower section of cab floor/fuel tank  18  is provided by pan  24 , which provides a plurality of reservoirs for fuel storage. A fuel return line  26  from a vehicle engine is provided into pan  24  along the forward edge of the pan. Front cab mounting points  36  and rear cab mounts  30  are also provided along the forward and trailing edges of deck  22 , respectively.  
         [0025]      FIGS. 3A  and B illustrate pan  24  for integrated cab floor/fuel tank  18  in greater detail. Pan  24  is preferably a single piece, steel stamping, and may be viewed as having a plurality of depressions, most of which are utilized as fuel reservoirs  50 ,  52 ,  54 ,  56 ,  58 ,  70  and  72 . Void  32  is included among the depression, but is reserved for providing space for the shift linkage for a standard transmission. Separating depressions  32 ,  50 ,  52 ,  54 ,  56 ,  58 ,  70  and  72  are a plurality of raised rails or dikes  78 ,  80 ,  82 ,  84 ,  86 ,  88  and  90 . Dikes  78 ,  80 ,  82 ,  84 ,  86 ,  88  and  90  are oriented either longitudinally (dikes  78  and  80 ) or latitudinally (the remainder) and are situated to replace a skeletal frame which supports permanent cab furnishings, e.g. seats, bunks, etc.  
         [0026]     Depressions  50 ,  52 ,  54 ,  56 ,  58 ,  70  and  72  intended for fuel storage are interconnected to one another by a series of channels or gaps  92 ,  94 ,  96 ,  98 ,  100  and  102  left in dikes  78 ,  80 ,  82 ,  84 ,  86 ,  88  and  90 . Channels  92 ,  94 ,  96 ,  98 ,  100  allow fuel to flow from one reservoir to an adjacent reservoir. Each of depressions  50 ,  52 ,  54 ,  56 ,  58 ,  70  and  72  intended for fuel storage is connected by at least one channel to an adjacent depression. The positions shown for channels  92 ,  94 ,  96 ,  98 ,  100  are preferably selected to assure that fuel eventually drains to depression  56 , from which fuel is drawn through a drain  76 . Depression  56  is located centrally from side to side of pan  24  and toward the back of the pan. In order to assure that fuel eventually drains to depression  56  the rear end of pan  24  is slightly lower than the forward end of the pan. Alternatively, the floors to the fuel storage depressions  50 ,  52 ,  54 ,  56 ,  58 ,  70  and  72  may be tilted to achieve the same result. For depressions  58 ,  72 ,  50  and  54  which have one outlet each, the floor of the depression should have its lowest point (when the vehicle is level) adjacent channels  98 ,  100 ,  90  and  94 , respectively. The floors of depressions  70  and  52  should have their lowest points adjacent channels  102  and  96  to depression  56 , respectively. Depression  56 , which includes drain  76 , has the drain as its lowest point. Fuel is of course not limited to flowing in one direction through channels  92 ,  94 ,  96 ,  98 ,  100 . Fuel returned or added to any one of depressions  50 ,  52 ,  54 ,  56 ,  58 ,  70  and  72  by a filler pipe or return line flows through the channels into the remaining depressions.  
         [0027]     Pan  24  is further provided with a four sided perimeter sill  74  which extends outwardly and horizontally on top of a four sided perimeter wall  45 . Perimeter wall  45  may be interrupted at various points by upward breaks associated with various of the dikes  78 ,  80 ,  82 ,  84 ,  88  and  90 . The interior face of perimeter wall  47  forms one or more of the sides of depressions  32 ,  50 ,  52 ,  54 ,  56 ,  58 ,  70  and  72 .  
         [0028]      FIG. 3B  illustrates one possible arrangement of channels where pan  24  is tilted to lower the rearward edge of the pan. Drain  76  is located adjacent the rearward edge of perimeter wall  45 , being substantially co-located with the lowest point in the chain of reservoir depressions  50 ,  52 ,  54 ,  56 ,  58 ,  70  and  72 . Fuel from Channels  98 ,  100  and  112  connect depressions  58 ,  70  and  72  to depression  56  along one side of the vehicle. Channels  90 ,  88  and  110  connect depressions  50 ,  52  and  54  to depression  56  along the opposite side of the vehicle.  
         [0029]     Referring to  FIG. 4  the rear portion of perimeter sill  74  is illustrated in a partial cutaway view to expose a two plane rear sill reinforcement bracket  116  which is nestled up under the perimeter sill. Similarly  FIGS. 5 and 6  illustrate the addition of reinforcement channels  120  and  122  to longitudinal and latitudinal dikes  180  and  182 . A channel  120  supporting dike  180  provides a front cab mount reinforcement attachment point. Dike  182  and reinforcement channel  122  are representative of the support provided for attachment of a seat and include modifications for installation and support of a seat including a tap hole  126  through dike  182  for insertion of a bolt for securing a seat and tap hole  124  with an associated nut  128  on reinforcement channel  122 . Nut  128  is typically welded to the bottom of channel  122 . Hole  124  is located axially aligned with a tap hole through dike  182 .  
         [0030]     As represented by  FIG. 7 , fuel depressions  50 ,  52 ,  54 ,  56 ,  58 ,  70  and  72  preferably each contain a foam insert such as illustrated by foam insert  130  for an exemplary depression  150 . Foam insert  130  is preferably a reticulated polyurethane block marketed as Explosion Suppressant Foam. The material is easily fabricated to conform to the interior shape of most any reservoir. The foam effectively controls fuel surging and sloshing and is available in the United States from Crest Foam Industries, Inc., 100. Carol Place, Moonachie, N.J. 07074.  
         [0031]      FIG. 8  illustrates in detail an area surrounding a drain  76  located on the floor  132  of depression  56 . Shallow channels  134  in floor  132  focus fuel flow toward drain  76 .  
         [0032]     Channels between fuel storage depressions in pan  24  are preferably located along perimeter wall  45  which leaves larger sections of the wall, particularly along the side of the vehicle, uninterrupted and smooth.  FIG. 9  illustrates location of a channel  100  between dike  84  and a section of perimeter wall  45  which leaves the perimeter wall uninterrupted.  
         [0033]     Referring to  FIG. 10 , some of the modifications which are possible for a truck tractor  10  after removal of fuel storage to an under cab position are illustrated. A deck plate  158  is visible under driver side  50  and perimeter wall  45  of fuel tank  18 . Outward from deck  18  is a battery box  152 . The removal of the cylindrical fuel tank allows the position of the battery box  152  to be standardized, since its location no longer depends upon the size of cylindrical fuel tank used on the vehicle. Located aft of battery box  152  is a rear cab access step  154 .  FIGS. 11 and 12  illustrate how perimeter wall  45  substitutes for a modesty panel  152  formerly installed on the vehicle for cosmetic reasons.  
         [0034]      FIG. 13  illustrates disposition of a driver&#39;s seat  42  supported on fuel tank  18 . Fuel tank  18  is preferably supported along its rear edge on a combination air spring, shock dampening suspension element  160 . Seat  42  has an undercarriage  164  which is mounted on deck  22  over dike  82 , which carries the weight of the seat. Suspension element  160  fits into a non-depressed portion of fuel tank  18 , and rests on a cross member  130  between the frame rails  13  and  12 .  
         [0035]     The invention provides simplification in tractor construction by allowing the replacement of cylindrical, strap on fuel tanks and cab floor sub-assemblies by use of a single, dual purpose, sub-assembly. No sacrifice in structural integrity of the cab should result. The fuel tank itself is well protected. Squeaks associated with rotation of cylindrical fuel tanks within their straps should be eliminated, contributing to creating an impression of a solidly built tractor cab. Fuel sloshing should be substantially eliminated improving vehicle handling. The need for fuel balancing between two outwardly disposed tanks is eliminated and thus the need for connections between the tanks and any pumps or check valves used in a balancing system is also eliminated.  
         [0036]     While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.