Abstract:
A rolling ball type mechanism is incorporated into a top-feed fuel injector so that the fuel injector has an outward appearance similar to that of known top-feed fuel injectors. The seat member is provided with a slot that makes the flow gradient more uniform over the flow area through the seat member.

Description:
FIELD OF THE INVENTION 
     This invention relates to fuel injector valves of the type used to inject fuel into an internal combustion engine other than directly into a combustion chamber of the engine. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     A fundamentally different type of fuel injector valve is disclosed in commonly assigned U.S. Pat. Nos. 5,178,115 and 5,197,675 of Paul D. Daly. The present invention relates to certain improvements in that type of fuel injector valve. 
     One improvement relates to configuring the actuating mechanism of such a valve in such a way that it can be packaged to look from the exterior much like a prior fuel injector, a top-feed fuel injector for example. 
     Another improvement relates to a means for reducing variations in the fuel velocity gradient over the area of the fuel flow through the valve seat member when the valve opens. 
     Further features, advantages, and benefits of the invention will be seen in the ensuing description and claims, which are accompanied by drawings. The drawings disclose a presently preferred embodiment of the invention according to the best mode contemplated at the present time for carrying out the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view having portions removed for illustrative purposes only, showing the general organization and arrangement of an exemplary fuel injector valve embodying principles of the invention. 
     FIG. 2 is a side elevational view of FIG. 1, on an enlarged scale and with portions broken away to show a portion in longitudinal cross section. 
     FIG. 3 is an enlarged fragmentary view of a portion of FIG. 2. 
     FIG. 4 is a transverse cross sectional view in the direction of arrows 4--4 in FIG. 3. 
     FIG. 5 is a fragmentary view in the direction of arrows 5--5 in FIG. 4. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1-5 disclose an exemplary fuel injector valve 10 embodying the improvements of the present invention. The fuel injector comprises a generally cylindrical body 12 have an axis 14. At the lower end of body 12, coaxial with axis 14, is a nozzle 16 from which fuel is injected, and at the upper end, also coaxial with axis 14, is a fuel inlet tube 18 through which fuel is introduced. On the exterior of body 12 is an electrical connector 20 that is adapted to be connected via external wiring (not shown) to a remotely located electronic control unit (not shown) for controlling the operation of the fuel injector. 
     Internally of body 12 is a mounting 22 for a generally cylindrical seat member 32 coaxial with axis 14. Seat member 32 has a frusto-conical surface 34 that funnels to a hole 36 at its smallest diameter. Seat member 32 has a cylindrical sidewall extending from the largest diameter of surface 34. A sphere 40 is bounded by sidewall 38 and in FIG. 1 is shown seated on surface 34, concentric with axis 14 in closure of hole 36. This represents the closed condition of the fuel injector in which sphere 40 is in contact with surface 34 at a circular locus 42 on surface 34. The sphere is resiliently urged to such concentricity by resilient means 44 that is coaxial with axis 14. This resilient means comprises a helical coil spring 46 acting on the sphere through a cap 48 that fits over the lower end of the spring within the interior of tube 18. The upper end of spring 46 bears against the lower end of an adjustment tube 50 that has been inserted a certain distance into tube 18 and fixed relative thereto to produce a desired spring force acting on sphere 40. 
     The fuel injector has a magnetic circuit within body 12 that is composed of a solenoid coil 52, a stator 54, and an armature 56. Coil 52 is disposed with its axis non-coaxial and non-parallel to axis 14. Stator 54 has a central portion disposed within the interior of coil 52 and portions that extend away from opposite ends of the coil. Since coil 52 is disposed above and to one side of valve seat member 32, the portions of the stator that extend from the opposite ends of the coil extend downwardly and then across the interior of body 12 in generally parallel fashion toward armature 56 such that the valve seat member 32 lies between them. 
     Armature 56 is in the form of a bar that is disposed along side sphere 40 and operated by the magnetic circuit to act on the sphere at essentially the midpoint of the bar indicated by the reference numeral 60. The sidewall of the seat member contains an opening 62 allowing the armature to act on the sphere. In the condition portrayed in FIGS. 1 and 2, which is for the solenoid coil not energized, the opposite ends of the bar are spaced from ends of the stator by generally equal working gaps 63 and the midpoint of the armature is in contact with the sphere at the end of a particular radial of the sphere. When the solenoid coil is energized, the magnetic flux that is generated in the magnetic circuit operates to reduce the working gaps 63 by attracting armature 56 toward the ends of the stator. This causes armature 56 to be moved bodily predominantly along the direction of an imaginary line that intersects axis 14 and that when viewed along axis 14 is essentially coincident with the radius of the sphere whose end is contacted by the midpoint of the armature. The cooperative effect of the motion of armature 56, of the resilience of resilient means 44, and of the angle of surface 34 is such that the sphere is moved from concentricity with axis 14 to eccentricity with axis 14 with the result that hole 36 opens. Sphere 40 is actually caused to roll slightly up seat 34. This condition is shown in FIG. 3, not necessarily to scale. When energization of the solenoid coil terminates, the magnetic attractive force that stator 54 had been exerting on the armature ceases, and this enables the resiliency of resilient means 44 to return the sphere to concentricity with axis 14 and resultant closure of hole 36. 
     Hole 36 is covered by a thin disk orifice 68 comprising one or more metering orifices through which fuel is injected into the engine. An O-ring seal 70 is seated in a groove extending around the outside of seat member 32 for sealing to mounting 22. Also with the interior space of body 12 is an electronic circuit assembly 72 that serves to operatively connect solenoid coil 52 with connector 20. When a signal for energizing coil 52 is applied across two of the terminals of connector 20, circuitry of assembly 72 actually applies to the coil a calibrated version of the applied signal, with the calibration factor having been previously programmed into the circuitry via a third terminal of connector 20, as explained in commonly assigned U.S. patent application Ser. No. 07/740,785. 
     A further feature of seat member 32 is a further opening in the form of a slot 76 that is provided in a semi-circumferential portion of seat member 32 opposite a semi-circumferential portion containing opening 62. Slot 76 has a circumferential dimension that is greater than its axial dimension. It intercepts surface 34 just below the maximum diameter of surface 34. The purpose of slot 76 is to provide a further ingress for fuel to pass through the seat member when sphere 40 is displaced from concentricity with axis 14 so that fuel flow through hole 36 has a more uniform velocity gradient over the flow area. In regard to fuel flow through the fuel injector it should be mentioned that fuel that has entered via inlet tube 18 is not confined to that tube and the interior of seat member 32; rather, provision is made so that fuel can also surround the outside of seat member 32 so as to be available to pass through both openings 62 and 76. 
     While a presently preferred embodiment of the invention has been illustrated and described, it should be appreciated that principles are applicable to other embodiments.