Jet pump for delivering fuel

Abstract

In a jet pump (22) for delivering fuel for a vehicle, a pre-filter for a nozzle (30) is formed in that a duct (47, 50) is formed between the nozzle (30) and a receptacle (36) for the nozzle in a pump body, the diameter of which duct is smaller than a diameter of a nozzle opening of the nozzle (30).

Claims

1. A jet pump (22) for delivering fuel, the jet pump comprising: a pump body (28) having a supply line (20) through which pressurized fuel enters the pump body (28), and a nozzle (30) having a nozzle opening (42) and an interior that opens into the nozzle opening (42), the nozzle (30) is arranged in a receptacle (36) in the pump body (28) and can be supplied with fuel via the supply line (20), wherein the receptacle (36) of the pump body (28) extends in an axial direction, the supply line (20) communicates with the receptacle (36), and a pre-filter is provided upstream of the nozzle (30), characterized in that the pre-filter for the nozzle (30) is defined by a duct having at least one gap that is formed between the nozzle (30) and the receptacle (36), the duct communicating with the interior of the nozzle (30), wherein fuel from the supply line (20) flows through the gap in an opposite direction to flow through the interior of the nozzle, the gap having a dimension (d2) in a radial direction that is smaller than a diameter of the opening (42) of the nozzle (30).

2. The jet pump (22) as claimed in claim 1, wherein the nozzle (30) has an annular wall (46) and a cover (40) that defines the nozzle opening (42), wherein the nozzle (30) with the annular wall (46) is arranged in the receptacle (36), wherein the duct is formed between an outside of the annular wall (46) and the receptacle (36) in the pump body (28).

3. The jet pump (22) as claimed in claim 1, wherein the pump body (28) has a mandrel (48) which protrudes into an annular wall (46) of the nozzle (30).

4. The jet pump (22) as claimed in claim 3, wherein the duct further extends between an inside of the annular wall (46) and the mandrel (48).

5. The jet pump (22) as claimed in claim 1, wherein the duct surrounds the nozzle (30).

6. The jet pump (22) as claimed in claim 1, wherein ribs (58, 60) are arranged in the duct.

7. The jet pump (22) as claimed in claim 6, wherein the ribs (58) are formed integrally with the nozzle (30).

8. The jet pump (22) as claimed in claim 6, wherein the ribs are formed integrally with the receptacle.

9. The jet pump (22) as claimed in claim 6, wherein the ribs (60) are mounted on an outside of a mandrel (48) protruding into the receptacle (36).

10. The jet pump (22) as claimed in claim 9, wherein the ribs are formed integrally with the receptacle.

11. The jet pump (22) as claimed in claim 1, wherein the pump body (28) is formed in a wall of a fuel reservoir (14).

12. The jet pump (22) as claimed in claim 1, wherein at least one of the pump body (28) and the nozzle (30) is formed integrally.

13. The jet pump (22) as claimed in claim 1, wherein a portion of the duct surrounds a mandrel (48), which protrudes into the nozzle (30).

14. The jet pump (22) as claimed in claim 13, wherein a portion of the duct surrounds the nozzle (30).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments of the invention are described in detail below with reference to the enclosed figures.

(2) FIG. 1 shows diagrammatically a fuel supply module according to one embodiment of the invention.

(3) FIG. 2 shows a longitudinal section through a jet pump according to one embodiment of the invention.

(4) FIG. 3 shows a longitudinal section through a jet pump according to a further embodiment of the invention.

(5) FIG. 4 shows a cross section through the jet pump shown in FIG. 3.

(6) FIG. 5 shows a longitudinal section through a jet pump according to a further embodiment of the invention.

(7) In principle identical or similar parts carry the same reference numerals.

DETAILED DESCRIPTION

(8) FIG. 1 shows diagrammatically a fuel supply module 10 comprising a fuel tank 12 in which is arranged a reservoir 14. In the reservoir 14 is a pump 16 which is adapted to deliver fuel via a first line 18 in the direction of an internal combustion engine, and to deliver fuel via a second line 20 from the reservoir 14 in the direction of a jet pump 22. The jet pump 22 is adapted to deliver fuel from the tank 12 into the reservoir 14. A fuel filter 24 can be located in the line 18 to filter the fuel delivered in the direction of the combustion engine. The pump 16 within the reservoir 14 can be operated by an electric motor which is supplied with electrical power via a line 26.

(9) FIG. 2 shows a diagrammatic longitudinal section through a suction jet pump 22. The jet pump 22 comprises a pump body 28 formed from a first material and a nozzle 30 which is formed from a second material separate from the pump body 28. The pump body 28 can be formed of the same plastic as the nozzle 30. It is however also possible for the pump body 28 and the nozzle 30 to be formed from different plastic materials.

(10) In the pump body 28 is formed a first supply line 20, via which the pressurized fuel originating from the pump 16 can enter the jet pump 22; the pump body 20 however also has a second supply line 32 which is connected to the tank 12. In addition a mixer pipe 34 is formed in the pump body 28, through which the fuel from the supply line 32 and the fuel jet from the nozzle 30 are mixed and delivered in the direction of an outlet into the reservoir 14.

(11) A receptacle 36 is formed in the pump body 28 and the nozzle 30 is inserted therein. The receptacle 36 is a tubular opening or recess in the pump body 28 which extends in the axial direction in which the nozzle 30 and the mixer pipe 34 also extend. The supply line 20 for the pressurized fuel opens into the receptacle 36 at the side. The receptacle 36 substantially has the same diameter over the entire axial extension direction. One exception is a groove 38 in the front region of the receptacle 36, which groove is adapted to receive an annular protrusion 37 extending radially about the nozzle 30 and serves to hold the nozzle 30 in the receptacle 36, in that the protrusion 37 engages in the groove 38.

(12) The nozzle 30 again in the front region has a substantially frustoconical cover 40, at the tip of which is formed the nozzle opening 42. The cover 40 is connected to an annular wall 44 which in a first segment has the same outer diameter as the inner diameter of the receptacle 36, whereby the fuel from the line 20 is forced to flow into the interior of the nozzle 30 and leave the nozzle 30 only via the nozzle opening 42.

(13) In a further segment 46 the nozzle 30 has an outer diameter which is smaller than the outer diameter of the receptacle 36. Thus in this region a duct 47 is formed between the inner wall of the receptacle 36 and the outer wall of the nozzle 30, through which duct the fuel from the line 20, which opens into the receptacle 36 in the region of the segment 46, flows into the interior of the nozzle 30. At the end of the receptacle 36 a mandrel 48 is formed in the pump body 28 and protrudes into the interior of the nozzle 30. The outer diameter of the mandrel 48 is smaller than the inner diameter of the nozzle 30, so that in this region a further duct 50 is formed, through which the fuel from the supply line 20 or duct 47 must flow before it can leave the nozzle 30 through the nozzle opening 42.

(14) The receptacle 36 is substantially cup-like, wherein the mandrel 48 protrudes from its base region in the axial direction. The mandrel 48 is a substantially cylindrical body, the end of which is slightly chamfered in the opening direction of the receptacle 36.

(15) Because diameter d.sub.1 of the nozzle opening 42 is greater than diameter d.sub.2 of the duct 47 and diameter d.sub.3 of the duct 50, ducts 47 and 50 form a filter region in which particles in the fuel from the supply line 20 can be captured so that the nozzle opening 42 cannot clog.

(16) FIG. 3 shows a further embodiment of a jet pump 22 which is substantially constructed like the jet pump 22 in FIG. 2. The jet pump 22 in FIG. 3 however has a receptacle 36 which has a greater diameter in a first segment 52 than in a second segment 52 which is further remote from the opening 42 of the nozzle 30. Since the supply line 20 opens into the receptacle 36 in the region 52, and the nozzle 30 has a smaller outer diameter in a segment of the region 52 than in the segment 52, in this region an annular cavity 56 is created in which the fuel from the line 20 can be distributed about the entire nozzle 30. In addition the jet pump 22 from FIG. 3 differs from that in FIG. 2 in that the nozzle 30 on its rear region has ribs 58 extending in the axial direction, and the mandrel 48 has ribs 60 extending in the axial direction.

(17) This is more clearly evident in FIG. 4 which shows a cross section through the jet pump 22 from FIG. 3 along line A-A. As shown in FIG. 4, the mandrel 48 together with its ribs 60 has an outer diameter which corresponds to the inner diameter of the nozzle 30 on a section line, wherein the ribs 60 have a height d.sub.3 in the radial direction and a spacing d.sub.5 in the peripheral direction. Thus between the mandrel 48 and the nozzle 30, a plurality of ducts 50 are formed, the diameter and cross section area of which are defined by the diameters d.sub.3 and d.sub.5.

(18) Similarly, the nozzle 30 on its outside has ribs 58 which touch the receptacle 36 in the region of the section line A-A. Thus the nozzle 30 in this region has an outer diameter which corresponds to the inner diameter of the receptacle 36 at this region. The ribs 58 of the nozzle 30 have a spacing d.sub.4 and a radial height d.sub.2. Thus between the inner face of the receptacle 36 and the outer face of the nozzle 30, a plurality of ducts 47 is formed. The diameter and cross section area of the ducts 47 are defined by the diameters d.sub.2 and d.sub.4.

(19) As evident from FIG. 3, the pressurized fuel flows from the supply line 20 first into the annular region 56 about the nozzle 30 where it is distributed, in order then to flow through the ducts 47 into the rearmost region of the receptacle 36, from there via the ducts 50 into the interior of the nozzle 30, and thereafter to leave the nozzle 30 through the opening 42. The diameters d.sub.3 and d.sub.5 of ducts 50 and diameters d.sub.2 and d.sub.4 of ducts 47 are dimensioned such that particles present in the fuel can remain captured therein if they are large enough to clog the nozzle opening 42. In this way a filter region is formed in the jet pump 22, which comprises the components 56, 50 and 47.

(20) Ribs 60 and 58 on mandrel 48 and at nozzle 30 can also serve to support the nozzle 30 in the receptacle 36 and on the mandrel 48, so that the rear region of the nozzle 30 or the front part of the mandrel 38 cannot swing to and from even under vibration. In this way it is ensured that the ducts 50 and 47 always have precisely the same diameter.

(21) FIG. 5 shows a further embodiment of a jet pump 22 in which the nozzle 30 has an annular wall 46, the outer diameter of which corresponds with the inner diameter of the receptacle 36 over the entire extension of the annular wall 46 in the radial direction. The inner diameter of the annular wall 46 in the region of the mandrel 48 is here slightly larger than the outer diameter of the mandrel 48 at this point. The inner diameter of the nozzle 30 and the outer diameter of the mandrel 48 are dimensioned such that their spacing d.sub.3 is smaller than diameter d.sub.1 of the nozzle opening 42. In this way an annular filter region 50 or duct 50 is formed about the mandrel 48, in which particles can be captured which would otherwise clog the nozzle opening 42.

(22) In the jet pump 22 in FIG. 5, the supply line 22 opens in the axial direction into the duct 50. In a segment which is not surrounded by the nozzle 30, the fuel from the supply line 20 can flow around the mandrel 48 so that it can flow around the entire mandrel 48 in the duct 50.

(23) In addition it must be pointed out that the term comprising does not exclude other elements or steps, and the terms one or a do not exclude a plurality. Furthermore it is pointed out that features or steps which are described with reference to one of the exemplary embodiments above can also be used in combination with other features or steps of other exemplary embodiments described above. Reference numerals in the claims should not be regarded as a restriction.