Abstract:
A fuel injector including a tube assembly having a longitudinal axis extending between a first end and a second end, a seat secured at the second end of the tube assembly and defining an opening. An armature assembly is movable along the longitudinal axis between first and second positions with respect to the seat. The armature includes a first set of passages permitting fluid flow therethrough and a second set of passages permitting vapor flow therethrough. Additionally, a method of dissipating fuel vapors in a fuel injector includes providing the armature with a first set of passages permitting fluid flow therethrough and a second set of passages permitting vapor flow therethrough.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to an armature, and more particularly to a fuel injector armature permitting separate fluid and vapor flow. 
     In the conventional art, it is known to use a fuel injector in an engine compartment of an automobile, for example. It is also known in the conventional art to use an armature in the fuel injector. Fuel flows from an inlet of the fuel injector, through an opening in the armature, to the outlet of the fuel injector. High engine operating temperatures, engine covers, and crowded engine compartments prevent air flow from cooling the fuel injector, which causes fuel disposed within the fuel injector to change from a liquid to a gaseous state (i.e., vaporize). Vaporization is more likely to occur when the engine has been heated (e.g., operated) and is then turned off, since the fuel injector and fuel remain hot, but cool liquid fuel is not being introduced into the system. Vaporized fuel can block the opening in the armature. When the vaporized fuel blocks the opening in the armature, liquid fuel is prevented from flowing through the fuel injector, and reliable engine restarts can be adversely affected. Thus, the engine must cool, thereby allowing the vaporized fuel to condense into a liquid, before the engine can be reliably restarted. 
     In the conventional art, it is known to cool the engine using a fan. However, this solution requires additional hardware (e.g., fan components), additional room in the engine compartment (e.g., permit adequate air flow paths, install fan components, etc.), and additional manufacturing and maintenance costs. Thus, it is desirable to have an improved fuel injector that dissipates the effects of vapor fuel flow when the engine has been heated and turned off, thereby allowing the engine to be reliably restarted. 
     SUMMARY OF THE INVENTION 
     The present invention provides a fuel injector. The fuel injector comprises a tube assembly having a longitudinal axis extending between a first end and a second end; a seat secured at the second end of the tube assembly, the seat defining an opening; and an armature assembly movable along the longitudinal axis between first and second positions with respect to the seat. The armature assembly is spaced from the seat such that fuel flow through the opening is permitted in the first position and the armature assembly contiguously engages the seat such that fuel flow through the opening is prevented in the second position. The armature includes a first set of passages permitting a first fluid flow in a first direction generally along the longitudinal axis; and a second set of passages permitting a second fluid flow in a second direction generally along the longitudinal axis, the second direction being generally opposite to the first direction. 
     The present invention also provides an armature assembly for a fuel injector. The armature moves along a longitudinal axis between first and second positions with respect to a seat having an opening. The armature assembly is spaced from the seat such that fuel flow through the opening is permitted in the first position and the armature assembly contiguously engages the seat such that fuel flow through the opening is prevented in the second position. The armature comprises a first set of passages permitting a first fluid flow in a first direction generally along the longitudinal axis; and a second set of passages permitting a second fluid flow in a second direction generally along the longitudinal axis, the second direction being generally opposite to the first direction. 
     The present invention also provides a method of dissipating fuel vapor in a fuel injector. The fuel injector has a tube assembly extending along a longitudinal axis between a first end and a second end. A seat is secured at the second end of the tube assembly and defines an opening. And an armature assembly that is movable along the longitudinal axis between first and second positions with respect to the seat. The armature assembly is spaced from the seat such that fuel flow through the opening is permitted in the first position and the armature assembly contiguously engages the seat such that fuel flow through the opening is prevented in the second position. The method comprises providing the armature with a first set of passages permitting liquid fuel flow in a first direction generally from the first end toward the second end; and providing the armature with a second set of passages permitting vapor fuel flow in a second direction generally from the second end toward the first end. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated herein and constitute part of this specification, illustrate an embodiment of the invention, and, together with the general description given above and the detailed description given below, serve to explain features of the invention. 
     FIG. 1 is a cross-sectional view of a fuel injector including an armature assembly according to the present invention. 
     FIG. 2 is a cross-sectional view of the armature assembly according to the present invention. 
     FIG. 3 is a bottom view of the armature assembly according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings, FIG. 1 shows a fuel injector  100  including an armature assembly  500 . The fuel injector  100  can be any conventional fuel injector, including top or bottom feeder fuel injectors or the like. 
     The fuel injector  100  includes a tube assembly having a fuel inlet end portion  110 , a fuel outlet end portion  150 , and the armature assembly  500 . As it is used in connection with the present invention, the term “assembly” can refer to a single homogenous material formation, a construction of multiple components that are generally fixed together, a group of operationally interrelated features, or a combination thereof. The fuel inlet end portion  110  of the fuel injector  100  is adapted to be operatively connected to a fuel rail (not shown). The fuel outlet end portion  150  of the fuel injector  100  is adapted to be operatively associated with a combustion chamber of an internal combustion engine (not shown). The fuel inlet and outlet end portions  110 , 150  define a fuel injector longitudinal axis  101 . The armature assembly  500  includes an armature assembly axis  501 . The armature assembly  500  is disposed between and in fluid communication with both the fuel inlet end portion  110  and the fuel outlet end portion  150  of the fuel injector  100 , such that the armature assembly axis  501  generally coaxial with the fuel injector longitudinal axis  101 . 
     During operation of the engine, fuel flows from the fuel rail (not shown) into the fuel inlet end portion  110  of the fuel injector  100 . Fuel flow continues from the fuel inlet end portion  110  of the fuel injector  100 , through the armature assembly  500  (to be discussed in detail later), to the fuel outlet end portion  150  of the fuel injector  100 . The fuel then flows from the fuel outlet end portion  150  of the fuel injector  100  to the combustion chamber of the engine (not shown). 
     The armature assembly  500  will now be discussed in detail. As shown in FIGS. 2 and 3, the armature assembly  500  includes a first portion  510  and a second portion  550 . The first portion  510  of the armature assembly  500  can be disposed proximate the fuel inlet portion end  110  of the fuel injector  100 . The second portion  550  of the armature assembly  500  can be disposed proximate the fuel outlet end portion  150  of the fuel injector  100 . 
     The first portion  510  includes a first surface  511  and a second surface  513 . The first and second surfaces  511 , 513  can be approximately flat, and can be generally parallel to each other. 
     An exterior surface  515  and an interior surface  517  are disposed between the first and second surfaces  511 , 513 . The exterior surface  515  defines a maximum radial dimension of the armature assembly  500 . The interior surface  517  defines a first portion of a first passage  521 . The first portion of the first passage  521  is adapted to permit fuel flow through the first portion  510  of the armature assembly  500 . The cross-sectional shapes of the exterior surface and interior surfaces  515 , 517  can be a variety of shapes. For example, each cross-section of the exterior surface  515  and the interior surface  517  can be substantially circular and coaxial with the armature assembly axis  501  such that the exterior and interior surfaces  515 , 517  define an annular wall  519 . 
     The annular wall  519  includes a second passage  531 . The second passage  531  is adapted to permit liquid fuel flow therethrough. The second passage  531  is in fluid communication with the first passage  521  of the armature  500  and the fuel outlet end portion  150  of the fuel injector  100 . By this arrangement, the second passage  531  can permit liquid fuel flow from the fuel inlet portion  110  to the fuel outlet portion  150  of the fuel injector  100 . 
     The second passage  531  extends along a second passage axis  532 . The second passage axis  532  can be disposed at an angle relative to the armature assembly axis  501  of the armature  500 . Preferably, the second passage axis  532  of the second passage  531  is disposed at an angle of about  10  degrees to the armature assembly axis  501  of the armature  500 . A cross-section of the second passage  531  can be a variety of shapes, e.g., substantially circular. A diameter of the second passage  531  can be greater than a fuel bore in a conventional armature. According to one example of the invention, the second passage  531  has a diameter of approximately 1.25 inches. 
     A set of second passages  531  can extend through the annular wall  519  of the armature assembly  500 . As it is used in connection with the present invention, the term “set” can refer to one or more examples of a feature. For example, four second passages  531  can be disposed in the armature assembly  500 . The four second passages  531  can be about equally spaced around the armature assembly axis  501 . 
     The first portion  510  of the armature  500  further includes a third passage  541 . The third passage  541  is adapted to permit vapor fuel flow therethrough. The third passage  541  is in fluid communication with the outlet end portion  150  and the inlet end portion  110  of the fuel injector  100 . By this arrangement, the third passage  541  is adapted to permit gaseous fuel to flow from generally the fuel outlet end portion  150  toward the fuel inlet end portion  110  of the fuel injector  100 . Thus, the third passage  541  offers an alternate path for fuel vapor to be displaced, thereby allowing liquid fuel to flow through the first and second passages  521 , 532 . 
     The third passage  541  can extend along a third passage axis  542 . The third passage axis can be generally parallel to the armature assembly axis  501  of the armature  500 . A cross-section of the third passage  541  can be a variety of shapes. For example, the cross-section of the third passage  541  can be a generally rectangular channel with radiuses corners. 
     A set of third passage  541  can be disposed in the armature assembly  500 . For example, four third passages  541  can be disposed in the armature assembly  500 . The four third passage  541  can be about equally spaced around the armature assembly axis  501 . Moreover, the set of third passages  541  can be angularly offset around the armature assembly axis  501  with respect to the set of second passages  531   
     The second portion  550  of the armature assembly  500  includes the second surface  513  and a third surface  551 . The second and third surfaces  513 , 551  can be generally flat, and can be generally parallel to each other. Moreover, the first, second, and third surfaces  511 , 513 , 551  can be generally parallel to one another. 
     An exterior surface  553  and an interior surface  555  are disposed between the second and third surfaces  513 , 551 . The exterior surface  553  defines a maximum radial dimension of the second portion  550 , which can be constricted with respect to the maximum radial dimension of the first portion  510 , as defined by the exterior surface  515 . The interior surface  555  defines a second portion of the first passage  521 . The second portion of the first passage  521  is also adapted to permit liquid fuel flow through the second portion  550  of the armature  500 . Each cross-section of the exterior surface  553  and an interior surface  555  can be of a variety of shapes. Each cross-section of the exterior surface  553  and the interior surface  555  can be substantially circular and coaxial with the armature assembly axis  501 . 
     While the present invention has been disclosed with reference to certain embodiments, numerous modifications, alterations, and changes to the described embodiments are possible without departing from the sphere and scope of the present invention, as defined in the appended claims. Accordingly, it is intended that the present invention not be limited to the described embodiments, but that it have the full scope defined by the language of the following claims, and equivalents thereof.