Fuel pump

Abstract

A fuel pump, including a driven impeller, which rotates in a pump housing and on the two sides comprises guide blades that each delimit a ring of blade chambers, and further including partial ring-shaped channels, which are arranged on both sides in the region of the guide blades in the pump housing and which form delivery chambers with the blade chambers for delivering fuel, wherein an inlet channel leads into the one delivery chamber and the other delivery chamber leads into an outlet channel, and mutually opposing blade chambers are connected to each other. The cross-sectional surface of the partial ring-shaped channel arranged on the inlet side decreases toward the end of the partial ring-shaped channel to zero. The region in which the cross-sectional surface decreases extends over an angular region of more than 45.

Claims

1. A fuel pump comprising: a pump housing; a driven impeller that rotates in the pump housing having guide vanes that delimit a ring of vane chambers between opposite axial sides of the driven impeller; partial ring-shaped ducts in the pump housing arranged facing the opposite axial sides of the driven impeller in a region of the guide vanes that form respective delivery chambers for delivering fuel with the vane chambers that lie opposite one another and are connected to one another bounded by respective wipers; a first inlet duct of the pump housing that opens into one delivery chamber, and an outlet duct that opens into the other delivery chamber; wherein a cross-sectional area of the partial ring-shaped duct arranged on the inlet side is constant in a first region proximate to the first inlet duct and decreases to zero by an end of the partial ring-shaped duct at a point that corresponds with one of the respective wipers that at least partially defines the outlet duct, a second region with the decreasing cross-sectional area is formed by two sub-regions, each sub-region having a respective slope, wherein the cross-sectional area decreases to a greater extent in a first sub-region than in a second sub-region, the second sub-region arranged downstream of the first sub-region, wherein the slope in the first sub-region is steeper than the slope in the second sub-region, and wherein the region in which the cross-sectional area decreases extends over an angular range of more than 45 and less than 150, measured from the outlet duct.

2. The fuel pump as claimed in claim 1, wherein the angular range is between 70 to 150.

3. The fuel pump as claimed in claim 2, wherein the angular range is 90.

4. The fuel pump as claimed in claim 2, wherein an angular range of the first sub-region is 30.

5. The fuel pump as claimed in claim 2, wherein an angular range of the second sub-region is 60.

6. The fuel pump as claimed in claim 1, wherein the cross-sectional area decreases linearly in both sub-regions.

7. The fuel pump as claimed in claim 1, wherein the two sub-regions merge with one another continuously.

8. A fuel pump as claimed in claim 2, comprising: a pump housing; a driven impeller that rotates in the pump housing having guide vanes that delimit a ring of vane chambers between opposite axial sides of the driven impeller; partial ring-shaped ducts in the pump housing arranged facing the opposite axial sides of the driven impeller in a region of the guide vanes that form respective delivery chambers for delivering fuel with the vane chambers that lie opposite one another and are connected to one another bounded by respective wipers; a first inlet duct of the pump housing that opens into one delivery chamber, and an outlet duct that opens into the other delivery chamber; wherein a cross-sectional area of the partial ring-shaped duct arranged on the inlet side is constant in a first region proximate to the first inlet duct and decreases to zero by an end of the partial ring-shaped duct at a point that corresponds with one of the respective wipers that at least partially defines the outlet duct, a second region with the decreasing cross-sectional area is formed by two sub-regions, each sub-region having a respective base wherein the cross-sectional area decreases to a greater extent in a first sub-region than in a second sub-region, the second sub-region arranged downstream of the first sub-region, wherein a duct base in the first sub-region curves convexly in the direction of the impeller, and wherein the region in which the cross-sectional area decreases extends over an angular range of more than 45 and less than 150, measured from the outlet duct.

9. The fuel pump as claimed in claim 8, wherein the angular range is between 70 to 150.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in more detail using a plurality of exemplary embodiments, in which:

(2) FIG. 1 is a fuel pump according to the invention,

(3) FIG. 2 is a schematic sectional illustration of the pump housing, and

(4) FIGS. 3-4 are further embodiments of the pump housing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) FIG. 1 shows a fuel pump 1 for delivering fuel from a fuel container 2 of a motor vehicle to an internal combustion engine 3. The fuel pump 1 has a pumping stage with a pump housing 4, which is composed of a pump lid 5 and a pump base 6 also referred to a pump floor 6. An impeller 7 is arranged in the pump housing. The impeller 7 is driven by a shaft 8 of an electric motor 9. The fuel which is drawn in from the fuel container 2 by the pumping stage via an inlet duct 10 is delivered to an outlet 12 via an outlet duct 11 and the electric motor 9. From said outlet 12, the fuel passes to the internal combustion engine 3 via a supply line 13.

(6) FIG. 2 shows part of the pump housing 4 with the pump lid 5, the pump base 6 and the impeller 7. The impeller 7 has a ring 14 of vanes 15, 15a, 15b on each of its two sides, wherein two vanes 15, 15a, 15b respectively bound a vane chamber 18, 19. The pump housing 4 has, in the region of the vanes 15, 15a, 15b, a partial ring-shaped duct 16, 17 on each of its two sides. The partial ring-shaped ducts 16, 17 form, together with the vane chambers 18, 19, delivery chambers 20, 21. Half of the delivery chambers 20, 21 are apportioned here to partial ring-shaped ducts 16, 17 and half to the vane chambers 18, 19, which lie opposite the respective partial ring-shaped duct 16, 17. The partial ring-shaped ducts 16, 17 start in the region of the inlet duct 10 and end in the region of the outlet duct 11 after an angular range of approximately 330. A wiper 22 adjoins the end of the partial ring-shaped ducts 16, 17 with respect to the rotational direction of the impeller 7, said wiper 22 being arranged between the outlet duct 11 and the inlet duct 10. While the partial ring-shaped duct 17 in the pump floor 6 has a constant cross-sectional area over wide parts of its extent, the partial ring-shaped duct 16 in the pump lid 5 has at its end a region 23 with a decreasing cross-sectional area. This region is delimited by the letters A and B in the FIG. 2. This region extends over an angular range of 90, wherein even relatively large angular ranges of, for example, 110 may be possible. The cross-sectional area decreases constantly over the profile of the region 23, with the result that a linear profile of the duct base is produced.

(7) FIG. 3 shows a second embodiment which differs from the fuel pump according to FIG. 2 only in the design of the region 23. The region is divided into two sub-regions 24, 25, wherein the first sub-region 24 has a greater reduction in the cross-sectional area than the second sub-region 25. The first sub-region therefore extends over an angular extent of 30, while the second sub-region 25 extends over 60. The two sub-regions 24, 25 each have a linearly extending duct base here. However, it is also conceivable for the two sub-regions 24, 25 to be constructed with equal lengths.

(8) A further embodiment is shown by FIG. 4. The duct base in the region 23 curves convexly in the direction of the impeller 7, wherein the curvature is most pronounced at the start of the region 23 with respect to the rotational direction of the impeller 7. The junction between the partial ring-shaped duct 17 and the region 23 is embodied in the form of a bend at the point A. However, it is also conceivable to make the junction continuous and therefore concave.

(9) Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.