Abstract:
A fuel pump for a vehicle includes a pump section having a flow channel and a rotatable impeller cooperating with said flow channel to pump fuel therethrough. The fuel pump also includes a motor section disposed adjacent the pump section and having a motor to rotate the impeller. The fuel pump further includes an outlet section disposed adjacent the motor section to allow pumped fuel to exit the fuel pump. The impeller includes a plurality of blades that are generally V shaped and have thinned edges.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates generally to fuel pumps for vehicles and, more particularly, to an impeller for a fuel pump of a vehicle.  
         BACKGROUND OF THE INVENTION  
         [0002]    It is known to provide a fuel tank in a vehicle to hold fuel to be used by an engine of the vehicle. It is also known to provide a fuel pump to pump fuel from the fuel tank to the engine. One type of fuel pump is known as a high-pressure turbine fuel pump. The high-pressure turbine fuel pump typically includes an impeller rotatable between inlet and outlet plates. The impeller is of a closed vane type to improve pump efficiency and performance. The impeller has a hub portion, a plurality of blade tips extending radially from the hub portion and disposed circumferentially thereabout and a peripheral ring portion extending radially from the blade tips. However, the closed vane impeller is hampered by flow loss and has shock losses due to fluid particles that contact the blade tips of the impeller.  
           [0003]    Therefore, it is desirable to provide an impeller for a fuel pump that reduces shock losses as fluid particles enter into the impeller from a channel in a pump section of the fuel pump. It is also desirable to provide an impeller in a fuel pump for a fuel tank in a vehicle that improves the mechanical efficiency of the high-pressure pump section of the fuel pump. It is further desirable to provide an impeller for a fuel pump which maximizes the volume of displacement between each blade.  
         SUMMARY OF THE INVENTION  
         [0004]    It is, therefore, one object of the present invention to a new impeller in a fuel pump for a fuel tank in a vehicle.  
           [0005]    It is another object of the present invention to provide an impeller for a fuel pump of a vehicle that reduces shock losses as the fluid particles enter into the impeller.  
           [0006]    To achieve the foregoing objects, the present invention is a fuel pump for a vehicle including a pump section having a flow channel and a rotatable impeller cooperating with the flow channel to pump fuel therethrough. The fuel pump also includes a motor section disposed adjacent the pump section and having a motor to rotate the impeller. The fuel pump further includes an outlet section disposed adjacent the motor section to allow pumped fuel to exit the fuel pump. The impeller has a plurality of blades that are generally V shaped and have thinned edges.  
           [0007]    One advantage of the present invention is that a new impeller for a fuel pump is provided for a vehicle. Another advantage of the present invention is that the impeller has a backside of V shaped blades brought to a thin edge to reduce shock losses as fluid particles enter into the impeller from a channel in a pump section of the fuel pump. Yet another advantage of the present invention is that the impeller maximizes the volume displacement between each blade, thereby increasing the flow path toroidal circulation within the impeller. Still another advantage of the present invention is that the impeller improves the overall mechanical efficiency of the high-pressure pump section. A further advantage of the present invention is that the impeller has a thin edged backside providing a thin blade that gives 25% higher head capability at shutoff and throughout the flow range with no increase in torque. Yet a further advantage of the present invention is that low voltage performance of the fuel pump is greatly improved versus standard straight blade technology.  
           [0008]    Other objects, features, and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a fragmentary elevational view of a fuel pump, according to the present invention.  
         [0010]    [0010]FIG. 2 is a plan view of an impeller, according to the present invention, of the fuel pump taken along line  2 - 2  of FIG. 1.  
         [0011]    [0011]FIG. 3 is a sectional view taken along line  3 - 3  of FIG. 2.  
         [0012]    [0012]FIG. 4 is a sectional view taken along line  4 - 4  of FIG. 2.  
         [0013]    [0013]FIG. 5 is an enlarged view of a portion of the impeller in circle  5  of FIG. 2. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]    Referring to the drawings and in particular FIGS. 1 and 2, one embodiment of a fuel pump  12 , according to the present invention, is shown for a vehicle (not shown). The fuel pump  12  includes a pump section  14  at one axial end, a motor section  16  adjacent the pump section  14 , and an outlet section  18  adjacent the motor section  16  at the other axial end. As known in the art, fuel enters the pump section  14 , which is rotated by the motor section  16 , and is pumped past the motor section  16  to the outlet section  18 . The outlet section  18  has an outlet member  20  extending axially with a passageway  22  extending axially therethrough. The outlet member  20  also has a plurality of projections or barbs  24  extending radially outwardly for attachment to a conduit (not shown). The outlet member  20  also includes a check valve  26  disposed in the passageway  22 . It should be appreciated that the fuel flowing to the outlet section  18  flows into the outlet member  20  and through the passageway  22  and check valve  26  when open to the conduit. It should also be appreciated that, except for the pump section  14 , the fuel pump  12  is conventional and known in the art.  
         [0015]    Referring to FIGS. 1 through 3, the pump section  14  includes an impeller  28 , according to the present invention, mounted to a rotatable shaft  29  of a motor  30  of the motor section  16  for rotation therewith. The impeller  28  is generally planar and circular in shape. The impeller  28  has a hub portion  31  attached to the shaft  29  by suitable means (not shown). The impeller  28  also has a plurality of blade tips  32  extending radially from the hub portion  31  and disposed circumferentially thereabout. The impeller  28  has a peripheral ring portion  33  extending radially from the blade tips  32  to shroud the blade tips  32 . The impeller  28  is made of a rigid material such as plastic.  
         [0016]    The pump section  14  also includes an inlet plate  34  disposed axially on one side of the impeller  28  and an outlet plate  36  disposed axially on the other side of the impeller  28 . The inlet plate  34  and outlet plate  36  are generally planar and circular in shape. The inlet plate  34  and outlet plate  36  are enclosed by a housing  38  and fixed thereto. The inlet plate  34  and outlet plate  36  have an inlet or first recess  40  and an outlet or second recess  42 , respectively, located axially opposite the blade tips  32  adjacent to the peripheral ring portion  33  to form a flow channel  43  for a function to be described. The recesses  40  and  42  are generally annular and allow fuel to flow therethrough from an inlet port (not shown) to an outlet port  44  of the pump section  14 . The peripheral ring portion  33  of the impeller  28  forms an outside diameter (OD) sealing surface  46  on both axial sides thereof with the inlet plate  34  and outlet plate  36 . It should be appreciated that the impeller  28  rotates relative to the inlet plate  34  and outlet plate  36  and the inlet plate  34  and outlet plate  36  are stationary relative to the impeller  28 .  
         [0017]    The pump section  14  also includes a spacer ring  48  disposed axially between the inlet plate  34  and outlet plate  36  and spaced radially from the impeller  28  to form a gap  50  therebetween. The spacer ring  48  is fixed to the housing  38  and is stationary relative to the impeller  28 . The spacer ring  48  is generally planar and circular in shape.  
         [0018]    Referring to FIGS. 2 through 5, the blade tips  32  have an inner diameter  52  and an outer diameter  54  and extend radially between the inner diameter  52  and the outer diameter  54 . The blade tips  32  of the impeller  28  each have a blade  56  that is generally “V” shaped. The blades  56  have a blade thickness at the inner diameter  52  greater than a blade thickness at the outer diameter  54 . In one embodiment, the blades  56  have a blade thickness of 0.212 inches at the inner diameter  52  and a blade thickness of 0.127 at the outer diameter  54 . The blades  56  are tapered or angled from the inner diameter  52  to the outer diameter  54  a predetermined amount such as 1.5 degrees from a radial axis thereof. The blades  56  have a root blade thickness at  58  greater than an edge blade thickness at  60 . In one embodiment, the blades  56  has a root blade thickness of 0.401 inches and an edge blade thickness  60  of 0.168 inches. The blades  56  have a predetermined blade angle such as forty-five degrees from the root blade thickness  58  to the edge blade thickness  60 . The blade tips  32  also have a plurality of blade cavities  62  disposed between the blades  56 . In one embodiment, the blade cavities  62  have a volume of 14.8286. It should be appreciated that fluid flows into the inlet recess  40  and through the blade cavities  62  and out the outlet recess  42 .  
         [0019]    In operation of the fuel pump  12 , the motor  30  rotates the shaft  29 , which in turn, rotates the impeller  28  as indicated by the arrow. The fluid velocity created at the rotating surface of the outside diameter or surface of the peripheral ring portion  33  of the impeller  28  coupled with the viscous force gradient within the fluid cause the fluid such as fuel to flow. The fuel flows from the inlet port through the flow channel  43  to the outlet port  44 .  
         [0020]    The present invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation.  
         [0021]    Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced other than as specifically described.