Protective cover assembly for a fuel pump

A protective cover assembly for a fuel pump in a motor vehicle 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 hooded cover defines 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. The proximate stud bolt includes an outer diameter feature which is operatively configured to engage with a plunger region of the pump assembly when the proximate cover assembly is subjected to a load.

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 toFIG. 1, many fuel pumps108implement a dampener118in order to dampen pressure oscillations—due to reciprocating movement of the plunger122in the pump108. As is known, the plunger122in a fuel pump108engages in three processes resulting in the reciprocating movement: (1) the plunger122moves to take in fuel from the fuel intake joint to the pressure chamber126; (2) the plunger122moves to deliver fuel from the pressure chamber126to the common rail; and (3) the plunger122moves to return fuel from the pressure chamber126to the fuel intake passage. The dampener118may be at least partially defined by at least one diaphragm120that is acted upon by lubrication pressure. Therefore, should a load130be applied to the dampener118, it is possible to risk the structural integrity of this liquid chamber. It is understood that the region of the pump108containing the plunger122is generally more robust relative to the dampener region134given that the plunger122is generally slidable within a cylindrical structure132in the fuel pump108, and therefore, the plunger region136is less susceptible to rupture risk in the event that a load130is applied to the plunger region136.

Because of the great pressure difference between the pressure in the pressure chamber126and the pressure in the drive mechanism chamber, the diaphragms120are optimally designed for pressure fluctuations. As shown inFIG. 1, these components, including the fuel pump plunger122, are traditionally protected by pump body110shown as element110inFIG. 1. However, when a load130is applied directly to pump body110, the pump body110may transfer the load130directly to the pressure chamber126having at least one diaphragm120, filled with liquid given that the pump body110closely encases the pressure chamber126(shown inFIG. 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.

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.

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.

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.

Referring now toFIG. 2, a cross sectional view of an example fuel pump10having a dampener with a pressure chamber and diaphragm(s)14together with a plunger16in a fuel pump body is shown. The example fuel pump10includes a dampener18having two diaphragms14joined together in a fluid filled pressure chamber12in order to dampen pressure oscillations—due to reciprocating movement of the plunger16in the pump10. As is known, the plunger16in a fuel pump10engages in three processes resulting in the reciprocating movement: (1) the plunger16moves to take in fuel from the fuel valve28to the pressure chamber68; (2) the plunger16moves to deliver fuel from the pressure chamber68to the common rail70; and (3) the plunger16moves to return fuel from the pressure chamber68to the fuel valve28. The pressure chamber68as well as the dampener18as shown are acted upon by pressure pulsations and therefore may be sensitive to external loads36applied to pressure chamber68and the dampener region20. It is understood that dampener region20may include the dampener18in addition to pressure chamber68.

A lifter138(shown inFIG. 1) may be provided at the end of plunger16which is then contacted to a cam140(shown inFIG. 1) by a spring90. The plunger16may be slidably held in cylinder32. The plunger16may 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 chamber68. The cylinder32may be sealed with a plunger seal142in order to prevent blowby of gasoline from leaking out toward the camshaft140(shown inFIG. 1). The fuel valve28opens and closes in synchronization with the reciprocating motion of the plunger16.

Given the fluid pressure and diaphragm(s)14used in the dampener portion20of the fuel pump10, the dampener18and pressure chamber68may be particularly vulnerable to external loads36thereby requiring protection. The present disclosure, therefore, provides a protective cover assembly30which deflects loads36applied toward the dampener region20and re-routes such loads36to prevent potential leaks in the dampener region20of the fuel pump10. It is understood that the plunger16disposed in the cylinder32is generally more robust and less vulnerable to external loads36due to the substantial structure provided in the plunger16/cylinder arrangement.

With reference toFIG. 2, a cross sectional view of another example fuel pump10is shown without the fuel pump cover assembly30of the present disclosure where the dampener portion20of the fuel pump10(with a pressure chamber) is disposed in the upper region of the fuel pump10and the plunger16(similar to that shown inFIG. 1) in the fuel pump body is disposed in the lower region of the fuel pump10. As shown, fuel intake port40attaches to the fuel pump10, and at least two stud bolts42,44of the cover assembly may be provided diagonally from one another to mount the fuel pump10in the vehicle. The proximate stud bolt42and the distal stud bolt44(shown inFIG. 4) may be used to mount the fuel pump to the cam carrier (shown inFIG. 3). It is also understood that the at least two stud bolts42,44(shown inFIG. 4) have sufficient vertical length such that the stud bolts42,44(shown inFIGS. 4 and 6) support the hooded cover (shown inFIG. 3) against any loads36(shown inFIG. 6) which may be directed to the dampener portion20of the fuel pump10—as explained in the present disclosure.

Referring now toFIG. 3, a perspective view of an example, non-limiting fuel pump cover assembly30according to various embodiments of the present disclosure is shown in phantom relative to the fuel pump10. As shown the fuel pump cover assembly30includes a first face46(substantially horizontal face) integral with a second face48(substantially diagonal face) disposed at an angle relative to the first face46. As shown inFIGS. 3-6, the second face48(substantially diagonal face) may be integral to one or more mounting flanges94to secure the hooded cover38to the cam carrier64at a lower end54of the fuel pump cover assembly30. Moreover, it is understood that the second face48(substantially diagonal face) may be positioned at an angle in the range of approximately 90 degrees to 180 degrees relative to the first face46(substantially horizontal face).

Referring now toFIG. 4, expanded views of two different embodiments of the cover assembly30are shown. InFIG. 4, stud bolts42,44are used to mount fuel pump10cam carrier and also used to secure hooded cover to fuel pump via top fasteners102which may engage with stud bolts42,44. Moreover, fasteners98may be used to secure lower portion of hooded cover at mounting flange94to cam carrier as shown.

As shown inFIG. 6, the first face46may define one or more apertures96to secure the stud bolts42,44which are operatively configured to support the hooded cover38against any loads36which may be directed to the dampener portion20. As shown inFIG. 2, a distal stud bolt44maintains the position of the distal end50of the first face46in order to maintain the first face46of the fuel pump cover assembly30completely over the dampener18. With reference now toFIG. 6, a cross sectional view of the example, non-limiting fuel pump cover assembly30and fuel pump10inFIG. 3along line6-6is shown. This cross section illustrates the proximate stud bolt42securing the fuel pump cover assembly30in a middle region52of the fuel pump cover assembly30. It is understood that the middle region52of the fuel pump cover assembly30is disposed between the lower portion54of the fuel pump cover assembly30and the distal region56of the fuel pump cover assembly36.

In the example shown inFIG. 5, the proximate stud bolt42is secured in an aperture96defined the middle region52. Accordingly, the proximate stud bolt42maintains the position of the middle region52of the fuel pump cover assembly30so as to protect the dampener region20of the fuel pump10in the event a load36(shown inFIG. 7) is applied toward the dampener region20. InFIG. 5, when load36is applied toward the dampener region20of the fuel pump10, the second face48of the fuel pump cover assembly30may slightly deflect and absorb energy from the load36while the proximate stud bolt42prevents the fuel pump cover assembly30from deflecting and interfering with the dampener region20of the fuel pump10. In an overload condition, an outer diameter feature43(shown as a hex feature) on stud bolt42will contact the plunger region17(lower region) of the fuel pump10as the stud bolt42absorbs energy from a load36. As indicated earlier, the plunger region17of the fuel pump is generally consider more robust in light of the plunger cylinder arrangement. As shown, the fasteners98affixed to the mounting flanges94also prevent the excessive displacement of the fuel pump cover assembly30(and potential interference with the dampener region) in the event that load36is applied toward the dampener region20.

With reference toFIG. 5, a side view of an example, non-limiting fuel pump cover assembly30is shown when no load is applied to the fuel pump cover assembly30. As shown inFIG. 5, a first predetermined distance58is provided between the midpoint62of the second face48and the vertical side92of the fuel pump10when no load is applied to toward the fuel pump10. However, when a load36is applied toward the dampener portion20of the fuel pump10, a second/shorter predetermined distance60is provided between the midpoint62of the second face48and the vertical side92of the fuel pump10due to the deflection of the fuel pump cover assembly30toward the fuel pump10, absorption of energy and transfer of energy from the applied load36ofFIG. 5.