Patent Publication Number: US-9897056-B1

Title: Protective cover assembly for a fuel pump

Description:
TECHNICAL FIELD 
     The invention relates generally to automotive fuel supply systems, and more particularly to a protective fuel pump cover used in automotive fuel supply systems. 
     BACKGROUND 
     Many automotive fuel supply systems include a fuel tank for storing fuel. In one arrangement, a fuel delivery module including, among other things, a housing, a fuel pump, and a fuel filter may be provided for an automotive vehicle. In one arrangement, the fuel pump may be arranged in-line with one or more fuel delivery lines. In operation, fuel typically travels through the fuel filter, into the fuel pump, and to an internal combustion engine. 
     A traditional fuel injection pump may include a membrane or movable wall which divides the storage chamber from the drive mechanism chamber. The membrane/diaphragm can reduce the sudden loading of the storage chamber by the fuel, which has been previously brought to injection pressure and is sent into the storage chamber at the end of the feed stroke that effects the injection, by virtue of the fact that the diaphragm yields to the pressure surge against the drive mechanism chamber, which is under a lower pressure, and offsets the outflow quantity. At the same time, during the intake stroke of the pump piston, the filling process of the pump work chamber is positively supported by the simultaneous volume change in the intake chamber and drive mechanism chamber. The pressure difference in the storage chamber and the drive mechanism chamber, which acts on this pump piston during its intake stroke, powers the pump piston in the intake stroke direction and obviates the need for a separate spring for returning the pump piston from its top dead center position to its bottom dead center position after the pressure or filling stroke. 
     Accordingly, with reference to  FIG. 1 , many fuel pumps  108  implement a dampener  118  in order to dampen pressure oscillations—due to reciprocating movement of the plunger  122  in the pump  108 . As is known, the plunger  122  in a fuel pump  108  engages in three processes resulting in the reciprocating movement: (1) the plunger  122  moves to take in fuel from the fuel intake joint to the pressure chamber  126 ; (2) the plunger  122  moves to deliver fuel from the pressure chamber  126  to the common rail; and (3) the plunger  122  moves to return fuel from the pressure chamber  126  to the fuel intake passage. The dampener  118  may be at least partially defined by at least one diaphragm  120  that is acted upon by lubrication pressure. Therefore, should a load  130  be applied to the dampener  118 , it is possible to risk the structural integrity of this liquid chamber. It is understood that the region of the pump  108  containing the plunger  122  is generally more robust relative to the dampener region  134  given that the plunger  122  is generally slidable within a cylindrical structure  132  in the fuel pump  108 , and therefore, the plunger region  136  is less susceptible to rupture risk in the event that a load  130  is applied to the plunger region  136 . 
     Because of the great pressure difference between the pressure in the pressure chamber  126  and the pressure in the drive mechanism chamber, the diaphragms  120  are optimally designed for pressure fluctuations. As shown in  FIG. 1 , these components, including the fuel pump plunger  122 , are traditionally protected by pump body  110  shown as element  110  in  FIG. 1 . However, when a load  130  is applied directly to pump body  110 , the pump body  110  may transfer the load  130  directly to the pressure chamber  126  having at least one diaphragm  120 , filled with liquid given that the pump body  110  closely encases the pressure chamber  126  (shown in  FIG. 1 ). 
     Accordingly, it would be desirable in the industry to produce a fuel pump cover which is designed to deflect loads imposed on the region of a fuel pump having a pressure chamber. 
     SUMMARY 
     Accordingly, the present disclosure provides a protective cover assembly for a fuel pump in a motor vehicle. The protective cover assembly includes a hooded cover having a first face and a second face in addition to distal and proximate stud bolts, and a base fastener. The second face of the hooded cover may be integral to the first face. The hooded cover may define a plurality of apertures operatively configured to receive a corresponding fastener. The distal stud bolt may be operatively configured to affix a distal end of the hooded cover to a cam carrier. The proximate stud bolt may be operatively configured to affix a middle region of the hooded cover to the cam carrier while the base fastener may be operatively configured to affix a lower portion of the hooded cover to the cam carrier. 
     It is understood that, in another embodiment, a protective cover assembly under the present disclosure may also include a hooded cover having a substantially horizontal face and a substantially diagonal face in addition to distal and proximate stud bolts, and a base fastener. The substantially diagonal face of the hooded cover may be integral to the first face. The hooded cover may define a plurality of apertures operatively configured to receive a corresponding fastener. The distal stud bolt may be operatively configured to affix a distal end of the substantially horizontal face to a cam carrier. The proximate stud bolt may be operatively configured to affix a middle region of the hooded cover to the cam carrier while the base fastener may be operatively configured to affix a lower portion of the substantially diagonal face to the cam carrier. 
     The present disclosure and its particular features and advantages will become more apparent from the following detailed description considered with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the present disclosure will be apparent from the following detailed description of preferred embodiments, and best mode, appended claims, and accompanying drawings in which: 
         FIG. 1  is a cross sectional view of a fuel pump engaged with a cam. 
         FIG. 2  is a cross sectional view of another fuel pump having a dampener with a pressure chamber and diaphragm(s) together with a plunger in a fuel pump body. 
         FIG. 3  is a perspective view of an example, non-limiting fuel pump cover according to various embodiments of the present disclosure. 
         FIG. 4  is an expanded view of a protective cover assembly according to various embodiments of the present disclosure. 
         FIG. 5  is a side view of a protective cover assembly according to various embodiments of the present disclosure when no load is applied to the cover assembly. 
         FIG. 6  is a cross sectional view of the example, non-limiting fuel pump cover and fuel pump in  FIG. 3  along line  6 - 6  when no load is applied to the cover assembly. 
     
    
    
     Like reference numerals refer to like parts throughout the description of several views of the drawings. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to presently preferred compositions, embodiments and methods of the present disclosure, which constitute the best modes of practicing the present disclosure presently known to the inventors. The figures are not necessarily to scale. However, it is to be understood that the disclosed embodiments are merely exemplary of the present disclosure that may be embodied in various and alternative forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for any aspect of the present disclosure and/or as a representative basis for teaching one skilled in the art to variously employ the present disclosure. 
     Except in the examples, or where otherwise expressly indicated, all numerical quantities in this description indicating amounts of material or conditions of reaction and/or use are to be understood as modified by the word “about” in describing the broadest scope of the present disclosure. Practice within the numerical limits stated is generally preferred. Also, unless expressly stated to the contrary: percent, “parts of,” and ratio values are by weight; the description of a group or class of materials as suitable or preferred for a given purpose in connection with the present disclosure implies that mixtures of any two or more of the members of the group or class are equally suitable or preferred; the first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and applies mutatis mutandis to normal grammatical variations of the initially defined abbreviation; and, unless expressly stated to the contrary, measurement of a property is determined by the same technique as previously or later referenced for the same property. 
     It is also to be understood that this present disclosure is not limited to the specific embodiments and methods described below, as specific components and/or conditions may, of course, vary. Furthermore, the terminology used herein is used only for the purpose of describing particular embodiments of the present disclosure and is not intended to be limiting in any way. 
     It must also be noted that, as used in the specification and the appended claims, the singular form “a,” “an,” and “the” comprise plural referents unless the context clearly indicates otherwise. For example, reference to a component in the singular is intended to comprise a plurality of components. 
     The term “comprising” is synonymous with “including,” “having,” “containing,” or “characterized by.” These terms are inclusive and open-ended and do not exclude additional, unrecited elements or method steps. 
     The phrase “consisting of” excludes any element, step, or ingredient not specified in the claim. When this phrase appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole. 
     The phrase “consisting essentially of” limits the scope of a claim to the specified materials or steps, plus those that do not materially affect the basic and novel characteristic(s) of the claimed subject matter. 
     The terms “comprising”, “consisting of”, and “consisting essentially of” can be alternatively used. Where one of these three terms is used, the presently disclosed and claimed subject matter can include the use of either of the other two terms. 
     Throughout this application, where publications are referenced, the disclosures of these publications in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this present disclosure pertains. 
     The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. 
     Referring now to  FIG. 2 , a cross sectional view of an example fuel pump  10  having a dampener with a pressure chamber and diaphragm(s)  14  together with a plunger  16  in a fuel pump body is shown. The example fuel pump  10  includes a dampener  18  having two diaphragms  14  joined together in a fluid filled pressure chamber  12  in order to dampen pressure oscillations—due to reciprocating movement of the plunger  16  in the pump  10 . As is known, the plunger  16  in a fuel pump  10  engages in three processes resulting in the reciprocating movement: (1) the plunger  16  moves to take in fuel from the fuel valve  28  to the pressure chamber  68 ; (2) the plunger  16  moves to deliver fuel from the pressure chamber  68  to the common rail  70 ; and (3) the plunger  16  moves to return fuel from the pressure chamber  68  to the fuel valve  28 . The pressure chamber  68  as well as the dampener  18  as shown are acted upon by pressure pulsations and therefore may be sensitive to external loads  36  applied to pressure chamber  68  and the dampener region  20 . It is understood that dampener region  20  may include the dampener  18  in addition to pressure chamber  68 . 
     A lifter  138  (shown in  FIG. 1 ) may be provided at the end of plunger  16  which is then contacted to a cam  140  (shown in  FIG. 1 ) by a spring  90 . The plunger  16  may be slidably held in cylinder  32 . The plunger  16  may therefore be caused to reciprocate by a cam rotated by an engine cam shaft or the like, which thereby changes the volume of the pressure chamber  68 . The cylinder  32  may be sealed with a plunger seal  142  in order to prevent blowby of gasoline from leaking out toward the camshaft  140  (shown in  FIG. 1 ). The fuel valve  28  opens and closes in synchronization with the reciprocating motion of the plunger  16 . 
     Given the fluid pressure and diaphragm(s)  14  used in the dampener portion  20  of the fuel pump  10 , the dampener  18  and pressure chamber  68  may be particularly vulnerable to external loads  36  thereby requiring protection. The present disclosure, therefore, provides a protective cover assembly  30  which deflects loads  36  applied toward the dampener region  20  and re-routes such loads  36  to prevent potential leaks in the dampener region  20  of the fuel pump  10 . It is understood that the plunger  16  disposed in the cylinder  32  is generally more robust and less vulnerable to external loads  36  due to the substantial structure provided in the plunger  16 /cylinder arrangement. 
     With reference to  FIG. 2 , a cross sectional view of another example fuel pump  10  is shown without the fuel pump cover assembly  30  of the present disclosure where the dampener portion  20  of the fuel pump  10  (with a pressure chamber) is disposed in the upper region of the fuel pump  10  and the plunger  16  (similar to that shown in  FIG. 1 ) in the fuel pump body is disposed in the lower region of the fuel pump  10 . As shown, fuel intake port  40  attaches to the fuel pump  10 , and at least two stud bolts  42 ,  44  of the cover assembly may be provided diagonally from one another to mount the fuel pump  10  in the vehicle. The proximate stud bolt  42  and the distal stud bolt  44  (shown in  FIG. 4 ) may be used to mount the fuel pump to the cam carrier (shown in  FIG. 3 ). It is also understood that the at least two stud bolts  42 ,  44  (shown in  FIG. 4 ) have sufficient vertical length such that the stud bolts  42 ,  44  (shown in  FIGS. 4 and 6 ) support the hooded cover (shown in  FIG. 3 ) against any loads  36  (shown in  FIG. 6 ) which may be directed to the dampener portion  20  of the fuel pump  10 —as explained in the present disclosure. 
     Referring now to  FIG. 3 , a perspective view of an example, non-limiting fuel pump cover assembly  30  according to various embodiments of the present disclosure is shown in phantom relative to the fuel pump  10 . As shown the fuel pump cover assembly  30  includes a first face  46  (substantially horizontal face) integral with a second face  48  (substantially diagonal face) disposed at an angle relative to the first face  46 . As shown in  FIGS. 3-6 , the second face  48  (substantially diagonal face) may be integral to one or more mounting flanges  94  to secure the hooded cover  38  to the cam carrier  64  at a lower end  54  of the fuel pump cover assembly  30 . Moreover, it is understood that the second face  48  (substantially diagonal face) may be positioned at an angle in the range of approximately 90 degrees to 180 degrees relative to the first face  46  (substantially horizontal face). 
     Referring now to  FIG. 4 , expanded views of two different embodiments of the cover assembly  30  are shown. In  FIG. 4 , stud bolts  42 ,  44  are used to mount fuel pump  10  cam carrier and also used to secure hooded cover to fuel pump via top fasteners  102  which may engage with stud bolts  42 ,  44 . Moreover, fasteners  98  may be used to secure lower portion of hooded cover at mounting flange  94  to cam carrier as shown. 
     As shown in  FIG. 6 , the first face  46  may define one or more apertures  96  to secure the stud bolts  42 ,  44  which are operatively configured to support the hooded cover  38  against any loads  36  which may be directed to the dampener portion  20 . As shown in  FIG. 2 , a distal stud bolt  44  maintains the position of the distal end  50  of the first face  46  in order to maintain the first face  46  of the fuel pump cover assembly  30  completely over the dampener  18 . With reference now to  FIG. 6 , a cross sectional view of the example, non-limiting fuel pump cover assembly  30  and fuel pump  10  in  FIG. 3  along line  6 - 6  is shown. This cross section illustrates the proximate stud bolt  42  securing the fuel pump cover assembly  30  in a middle region  52  of the fuel pump cover assembly  30 . It is understood that the middle region  52  of the fuel pump cover assembly  30  is disposed between the lower portion  54  of the fuel pump cover assembly  30  and the distal region  56  of the fuel pump cover assembly  36 . 
     In the example shown in  FIG. 5 , the proximate stud bolt  42  is secured in an aperture  96  defined the middle region  52 . Accordingly, the proximate stud bolt  42  maintains the position of the middle region  52  of the fuel pump cover assembly  30  so as to protect the dampener region  20  of the fuel pump  10  in the event a load  36  (shown in  FIG. 7 ) is applied toward the dampener region  20 . In  FIG. 5 , when load  36  is applied toward the dampener region  20  of the fuel pump  10 , the second face  48  of the fuel pump cover assembly  30  may slightly deflect and absorb energy from the load  36  while the proximate stud bolt  42  prevents the fuel pump cover assembly  30  from deflecting and interfering with the dampener region  20  of the fuel pump  10 . In an overload condition, an outer diameter feature  43  (shown as a hex feature) on stud bolt  42  will contact the plunger region  17  (lower region) of the fuel pump  10  as the stud bolt  42  absorbs energy from a load  36 . As indicated earlier, the plunger region  17  of the fuel pump is generally consider more robust in light of the plunger cylinder arrangement. As shown, the fasteners  98  affixed to the mounting flanges  94  also prevent the excessive displacement of the fuel pump cover assembly  30  (and potential interference with the dampener region) in the event that load  36  is applied toward the dampener region  20 . 
     With reference to  FIG. 5 , a side view of an example, non-limiting fuel pump cover assembly  30  is shown when no load is applied to the fuel pump cover assembly  30 . As shown in  FIG. 5 , a first predetermined distance  58  is provided between the midpoint  62  of the second face  48  and the vertical side  92  of the fuel pump  10  when no load is applied to toward the fuel pump  10 . However, when a load  36  is applied toward the dampener portion  20  of the fuel pump  10 , a second/shorter predetermined distance  60  is provided between the midpoint  62  of the second face  48  and the vertical side  92  of the fuel pump  10  due to the deflection of the fuel pump cover assembly  30  toward the fuel pump  10 , absorption of energy and transfer of energy from the applied load  36  of  FIG. 5 . 
     While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and the legal equivalents thereof.