High-pressure fuel pump

Abstract

The invention relates to a high pressure fuel pump (10) comprising a housing (12) and a flange (14) by means of which the housing (12) can be fastened to an engine block or cylinder head, the flange (14) being formed of at least two flange parts (26) that are separate from the housing (12) and are separated from each other, and that overlap mutually in the fastened state of the housing (12).

Claims

1. A high pressure fuel pump comprising: a housing configured to receive at least one high pressure generating element for generating a high pressure in the fuel; a flange configured to fasten the housing to at least one of a cylinder head and an engine block of an internal combustion engine, the flange being separate from the housing and comprising at least two flange parts, the flange parts separated from one another and each configured to engage around a respective part circumferential region of the housing, the flange parts configured to overlap mutually in the fastened state of the housing.

2. The high pressure fuel pump as claimed in claim 1 wherein each flange part comprises a first flange part end region and a second flange part end region, the flange parts configured to overlap both in the first flange part end region and in the second flange part end region in the fastened state of the housing.

3. The high pressure fuel pump as claimed in claim 2 wherein each flange part defines a first flange plane and a second flange plane, the flange planes offset in parallel with respect to one another, the first flange part end region arranged in the first flange plane, and the second flange part end region arranged in the second flange plane.

4. The high pressure fuel pump as claimed in claim 2, wherein each flange part defines at least one screw hole for guiding through a fastening bolt in the first and in the second flange part end region, the flange parts configured to facilitate the screw holes of the first flange part and the second flange part to overlap in the fastened state of the housing.

5. The high pressure fuel pump as claimed in claim 2, wherein each flange part is rotationally symmetrical about a center axis, the center axis dividing the flange part centrally between the first flange part end region and the second flange part end region.

6. The high pressure fuel pump as claimed in claim 1, wherein each flange part defines a partially circular recess for receiving the respective part circumferential region of the housing, a contact web for acting on the part circumferential region configured in the recess, the contact web extending in the recess.

7. The high pressure fuel pump as claimed in claim 6, wherein the contact web extends in the recess partially.

8. The high pressure fuel pump as claimed in claim 6, wherein the contact web extends over between 50% and 80% of the partial circle of the recess.

9. The high pressure fuel pump as claimed in claim 1, wherein, in the fastened state of the housing, each flange part extends over more than half of a circumference of the housing.

10. The high pressure fuel pump as claimed in claim 1, wherein the at least two flange parts are of identical configuration with respect to one another.

11. The high pressure fuel pump as claimed in claim 1, wherein, in the fastened state of the housing, the flange formed from the at least two flange parts surrounds a circumference of the housing completely.

12. The high pressure fuel pump as claimed in claim 1, wherein at least one of the housing comprises a circumferential projection, on which the at least two flange parts are supported, and the housing defines a groove of complementary configuration to a respective supporting region of the at least two flange parts, and the respective supporting region engaging with the groove.

Description

(1) One advantageous refinement of the invention will be described in greater detail in the following text using the appended drawings, in which:

(2) FIG. 1 shows a perspective illustration of a high pressure fuel pump having a flange for fastening the high pressure fuel pump to a cylinder head or to an engine block,

(3) FIG. 2 shows a perspective illustration of the high pressure fuel pump from FIG. 1, a flange part of the flange having been removed,

(4) FIG. 3 shows a plan view of the flange part which remains on the high pressure fuel pump in FIG. 2,

(5) FIG. 4 shows a perspective illustration of the flange part from FIG. 3, and

(6) FIG. 5 shows a plan view of two flange parts according to FIG. 3 and FIG. 4, which flange parts overlap in an overlap region.

(7) FIG. 1 shows a perspective illustration of a high pressure fuel pump 10 which has a housing 12 and a flange 14.

(8) At least one high pressure generating element 16, such as a pump piston 18, is accommodated in the housing 12, and an inflow line 20, an outflow line 22 and a damper 24 are fastened thereto.

(9) In order for it to be possible to fasten the housing 12, for example, to a cylinder head or an engine block of an internal combustion engine, with the result that a drive element, such as an eccentric shaft, can drive the pump piston 18 in a translational movement, the flange 14 is provided which holds down the housing 12 on the cylinder head or the engine block.

(10) This is because, in order for it to be possible to provide the function of the high pressure fuel pump 10 which is configured as a piston pump and is to be integrated in a fuel injection system of an internal combustion engine, the high pressure fuel pump 10 has to be fixed on the engine block or the cylinder head by means of the flange 14. Said flange 14 is normally attached on the high pressure fuel pump 10 by means of a welded seam, that is to say in an integrally joined manner. The welded seam does not permit any reorientation of the flange 14, however, which can lead to increased problems with regard to time-critical example constructions, for example, in a tendering phase. The high pressure fuel pump 10 is therefore normally mounted on the cylinder head or the engine block via bolts by means of a fixedly welded flange 14 on the housing 12. Said flange 14 does not permit any subsequent reorientation of the high pressure fuel pump 10 which might possibly be useful in the case of installation space tests. The flexibility and therefore the orientation possibilities are limited merely to the predefined orientation of the high pressure fuel pump 10.

(11) A flange 14 is therefore then arranged on the high pressure fuel pump 10 according to FIG. 1, which flange 14 represents a split flange concept which permits a free orientation of the high pressure fuel pump 10 and nevertheless fulfills the requirements made of the flange 14, such as holding down the high pressure fuel pump 10, without excessive ventilating, and the fixing function. As a result of the multiple-piece flange concept, the delivery time of samples is shortened considerably, and a welding step can be dispensed with.

(12) The flange 14 in FIG. 1 has two flange parts 26 which are separated from one another and are connected to form an overall flange 14 by way of an overlap in two overlap regions 28. Here, each flange part 26 engages around in each case one part circumferential region 30 of the housing 12. The two flange parts 26 together, as an overall flange 14, engage completely around the housing circumference 32 of the housing 12.

(13) FIG. 2 shows the high pressure fuel pump 10 from FIG. 1, likewise in a perspective illustration, one of the two flange parts 26 having been removed.

(14) It can be seen that, in the present embodiment, the housing 12 has a circumferential projection 34, on which the flange parts 26 can be supported, to be precise by way of a supporting region 36 which lies on the projection 34. In the present embodiment, the supporting region 36 is formed as a contact web 38 which will be described in greater detail in the following text. As an alternative to the projection 34, it is also possible to provide a groove on the housing 12, which groove is of complementary configuration with respect to the supporting region 36, with the result that the flange parts 26 can engage into the groove, and can thus apply a fastening force to the housing 12.

(15) As is apparent from FIG. 2, each flange part 26 extends over more than half of the housing circumference 32, with the result that an overlap is possible in the overlap regions 28 of the two flange parts 26. Instead of a two-piece flange arrangement, it is also possible to provide a plurality of individual flange parts 26 which are configured separately from one another and in a separated manner from the housing 12; more overlap regions 28 are then accordingly also arranged on the flange 14.

(16) In the preferred refinement, in which two flange parts 26 are provided, they are of identical configuration with respect to one another, with the result that the principle of identical parts can be applied and a cost advantage arises in the production of the individual flange parts 26.

(17) The configuration of the individual flange parts 26 will be described in greater detail in the following text with reference to FIG. 3 and FIG. 4.

(18) FIG. 3 shows a plan view of a flange part 26, whereas FIG. 4 shows a perspective view of the flange part 26 from FIG. 3.

(19) The flange part 26 has a first flange part end region 40 and a second flange part end region 42, in which in each case one screw hole 44 is arranged. As is apparent from FIG. 1, two flange parts 26 overlap precisely in said two flange part end regions 40, 42. This means that the screw holes 44 which are situated in said flange part end regions 40, 42 in the two flange parts 26 also overlap in the fastened state of the housing 12, and that a fastening bolt is plugged jointly through two overlapping screw holes 44. The two flange parts 26 are thus not only fastened to one another such that they cannot be moved with respect to one another, but rather at the same time the housing 12 is also fastened to the cylinder head or the engine block.

(20) Each flange part 26 has a partially circular recess 46, by way of which the flange part 26 surrounds the part circumferential region 30 of the housing 12. The contact web 38 is arranged in said recess 46, by way of which contact web 38 the respective flange part 26 is supported on the projection 34 of the housing 12. The contact web 38 does not extend completely over the circumference of the recess 46, but rather merely partially over the recess 46, preferably over between 50% and 80% of the partial circle 48 which is formed by the recess 46. The two contact webs 38 complete one another by way of the overlap of the two flange parts 26 in the overlap regions 28, with the result that, in the assembled state of the two flange parts 26, a contact web 38 is provided on the flange 14, which contact web 38 can be supported over the entire housing circumference 32 on the projection 34 of the housing 12.

(21) Each flange part 26 has a step 50, with the result that the flange part 26 comprises a first flange plane 52 and a second flange plane 54. Said step 50 and the two flange planes 52, 54 can be seen particularly clearly in the perspective illustration in FIG. 4. The two flange planes 52, 54 are arranged offset in parallel with respect to one another, in order thus to form the step 50. The flange part end regions 40, 42, in which the flange parts 26 which are to be connected to one another overlap, are not arranged in one plane, but rather the first flange part end region 40 is arranged in the first flange plane 52 and the second flange part end region 42 is arranged in the second flange plane 54. In the case of an overlap of two flange parts 26 in said flange part end regions 40, 42, this results in an overall flange 14 which is of level configuration on its surface.

(22) Each flange part 26 is of rotationally symmetrical configuration about a center axis 56 which divides the flange part 26 centrally between the first flange part end region 40 and the second flange part end region 42, as can be seen in FIG. 3. If the flange part 26 is rotated by 180 about said center axis 56, its outer shape is transformed into itself. As a result, the same flange part 26 can be used in FIG. 1 both as a flange part 26 which is arranged at the rear and as a flange part 26 which is arranged at the front, merely in each case in a rotated form.

(23) FIG. 5 shows a plan view of two flange parts 26 which already overlap partially in one of the overlap regions 28. If the two flange parts 26 are also pushed together in the opposite overlap region 28, they together form the overall flange 14 which can then hold down the housing 12 of the high pressure fuel pump 10 on a cylinder head or on an engine block.