High-pressure fuel pump

Abstract

The invention relates to a high-pressure fuel pump (1), in particular of a common rail injection system of an internal combustion engine, having a pump cylinder head (3), having an intake valve (6) arranged in the pump cylinder head (3) in the direction of a pump cylinder axis, and a high-pressure fuel outlet (5) arranged laterally on the pump cylinder head (3), wherein a protective cap (10, 10a) at least partly covering the high-pressure fuel pump (1) is provided. According to the invention, a high-pressure fuel pump (1) having a protective cap (10, 10a) is provided, in which the protective cap (10, 10a) can be mounted without difficulty on an assembled high-pressure fuel pump (1). This is achieved in that a plug (8) having a lateral lead connection (9) is placed on the electrically operated intake valve (6), and the protective cap (1) is formed in two pieces and has two protective cap parts (11a,11b) that can be fitted to each other, or else in that a plug (8) having a lateral lead connection (9) is placed on the electrically operated intake valve (6), and the protective cap (10a) is formed annularly and has a free clearance slot (19) interrupting the ring.

Claims

1. A high-pressure fuel pump (1), comprising a pump cylinder head (3), a suction valve (6) arranged in a direction of a pump cylinder axis in the pump cylinder head (3), a high-pressure fuel outlet (5) arranged laterally on the pump cylinder head (3), and a ring-shaped protective cap (10a) which at least partially covers the high-pressure fuel pump (1), wherein an electrical plug (8) with a lateral line connector (9) is mounted onto the electrically actuated suction valve (6), and wherein the protective cap (10a) has a clearance slot (19) which interrupts the ring-shaped protective cap (10a).

2. The high-pressure fuel pump (1) as claimed in claim 1, characterized in that the clearance slot (19) has a contour which surrounds the high-pressure fuel outlet (5).

3. The high-pressure fuel pump (1) as claimed in claim 1, characterized in that the protective cap (10a) has clamping lugs (20) which adjoin the clearance slot (19) and which interact with a clamping ring (21).

4. The high-pressure fuel pump (1) as claimed in claim 3, characterized in that the clamping ring (21) has a covering lug (22) for at least partially covering the clearance slot (19).

5. The high-pressure fuel pump (1) as claimed in claim 1, characterized in that the protective cap (10a) has a domed projection which extends in a direction of the electrical plug (8).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantageous embodiments of the invention emerge from the description of the drawings, in which exemplary embodiments of the invention illustrated in the figures are described in more detail.

(2) In the figures:

(3) FIG. 1 shows a perspective partial view of a high-pressure fuel pump with a mounted protective cap which is composed of two protective cap parts,

(4) FIG. 2 shows a further perspective partial view of a high-pressure fuel pump with a mounted protective cap,

(5) FIG. 3 shows a side view of a high-pressure fuel pump with, in section, a protective cap,

(6) FIG. 4 shows a detailed view of a protective cap,

(7) FIG. 5 shows a perspective partial view of a high-pressure fuel pump with a protective cap which has a domed projection,

(8) FIG. 6 shows a perspective partial view of a high-pressure fuel pump with a mounted protective cap in a further embodiment,

(9) FIG. 7 shows a further partial view of a high-pressure fuel pump with a protective cap analogous to FIG. 6,

(10) FIG. 8 shows a further perspective partial view of a high-pressure fuel pump with a protective cap analogous to FIG. 6,

(11) FIG. 9 shows a further perspective partial view of a high-pressure fuel pump with a mounted protective cap analogous to FIG. 6, and

(12) FIGS. 10a and 10b are plan views of a two-part protective cap with film hinge a) open and b) closed.

DETAILED DESCRIPTION

(13) FIGS. 1 and 2 show the upper part of a high-pressure fuel pump 1 having a pump housing 2 on which a pump cylinder head 3 (see in particular FIG. 2) is mounted. By contrast to FIG. 1, FIG. 2 shows a protective cap 10 that has been sectioned in the plane of the high-pressure fuel outlet 5, in order to provide a better illustration of the pump cylinder head 3. The pump cylinder head 3 is fastened to the pump housing 2 by means of four screws 4, and has a lateral high-pressure fuel outlet 5. A high-pressure line is fastenable to the high-pressure fuel outlet 5, through which high-pressure line the fuel delivered by the high-pressure fuel pump 1 is conducted into a high-pressure accumulator. The high-pressure fuel pump 1 is preferably part of a common-rail injection system which is installed on an internal combustion engine. Here, the high-pressure fuel pump 1 is fed with fuel from a low-pressure system through a feed arranged in the pump housing 2 and in the pump cylinder head 3, wherein the metered fuel quantity is determined by a suction valve 6 formed as an electrically actuated valve. The suction valve 6 is fastened to the pump cylinder head 3 by means of a sleeve nut 7. The suction valve 6 connects the feed to a pump working chamber in the pump cylinder head 3 in order to define the fuel delivered by the high-pressure fuel pump 1. An electrical plug 8 with a lateral line connector 9 is mounted onto the suction valve 6. The line connector 9 is preferably formed in one piece with an onward-leading signal line (not illustrated) which is connected to a control unit for actuating the suction valve. In the exemplary embodiment illustrated, the electrical plug 8 is oriented with the lateral line connector 9 rotated relative to the high-pressure fuel outlet 5 through approximately 90.

(14) Onto the pump cylinder head 3, which is produced from a metallic material, for example by casting, and which is metallically blank on its surface pointing toward the surroundings, there is mounted a protective cap 10 which is composed of two protective cap parts 11a, 11b. The parting plane 12 that defines the two protective cap parts 11a, 11b runs transversely with respect to, in particular, the high-pressure fuel outlet 5. Accordingly, the protective cap part 11b has a recess 13 which surrounds the high-pressure fuel outlet 5 and which is open toward the pump housing 2. The two protective cap parts 11a, 11b have in each case one detent hook 14, which can be engaged into an oppositely situated detent groove 15 of the other protective cap part 11b, 11a. Alternatively, at one side, instead of a detent hook 14 and a detent groove 15, the two protective cap parts 11a, 11b may also have a hinge which connects the two protective cap parts 11a, 11b. The protective cap parts 11a, 11b are preferably produced from a plastics material, such that the hinge may be formed as an elastic lug which connects the two protective cap parts 11a, 11b.

(15) To ensure a secure seat of the protective cap 10 on the pump cylinder head 3, the two protective cap parts 11a, 11b have clamping lugs 16 which, as can be seen from FIG. 3, project under the sleeve nut 7.

(16) FIG. 4 shows a further embodiment of the clamping lugs 16 of the two protective cap parts 11a, 11b, which are additionally hooked one into the other.

(17) FIG. 5 shows a protective cap 10 analogous to the embodiments described in the preceding figures, wherein, in the embodiment illustrated in FIG. 5, the protective cap 10 has a domed projection 17 which surrounds the sleeve nut 7 and which in turn is composed of two domed projection parts 18a, 18b, which are in each case formed in one piece with the protective cap parts 11a, 11b. Ultimately, by means of this embodiment, a possible ingress of water into the suction valve 6 is reduced in that a partition with respect to the lower region of the sleeve nut 7 is realized by means of the protective cap 10 together with the domed projection 17.

(18) In the embodiments of the protective cap 10a illustrated in FIGS. 6 to 9, said protective cap is of ring-shaped form and has a clearance slot 19 which interrupts the ring. The protective cap 10a is mounted by being fitted, as illustrated in FIG. 6, over the electrical plug 8 with the lateral line connector 9, then, when situated below the lateral line connector 9, being rotated as shown in FIG. 7 such that the clearance slot 19 lies above the lateral high-pressure fuel outlet 5, and then being fitted over the pump cylinder head 3 until it makes contact with the pump housing 2, as shown in FIG. 8. The protective cap 10a has clamping lugs 20 arranged to both sides of the clearance slot 19. A clamping ring 21 can be pushed onto said clamping lugs 20, as illustrated in FIG. 9. The clamping ring has a covering lug 22 which, when the clamping ring 21 has been mounted, covers the clearance slot 19 at the top wall of the protective cap 10a.

(19) The protective cap 10a may also have a domed projection (not illustrated) which has an elongated slot above the clearance slot. The domed projection is preferably formed from an elastic plastic, such that it can be rotated under the line connector 9 in a reversibly deformable manner. In this embodiment, the clamping ring may be designed such that a widened covering lug also covers the clearance slot of the domed projection. Alternatively, the domed projection may also be formed separately from the protective cap 10a and mounted after the protective cap 10a has been mounted.

(20) FIG. 10 shows a unipartite embodiment of a two-part protective cap 10. This is because, in this case, the two protective cap parts 11a and 11b are connected by means of a film hinge 23. The pivot axis of the film hinge 23 runs parallel to the pump cylinder longitudinal axis, such that two protective cap parts 11a and 11b in the form of two half-shells are formed, which are pivotable relative to one another. The parting plane 12 running through the pivot axis is, with regard to its angular position, arranged offset with respect to the center of the recess 13 by 90. The recess 13, which serves for receiving the high-pressure fuel outlet 5, is in the present case formed in the protective cap part 11b.

(21) During the mounting of the protective cap 10, the two protective cap parts 11a and 11b are pivoted relative to one another such that an opening is formed on the side situated opposite the film hinge 23 (see FIG. 10a). The opening enables the protective cap 10 to be placed onto the pump cylinder head 3 such that the high-pressure fuel outlet 5 comes to lie within the recess 13 of the protective cap part 11b. The other protective cap part 11a is subsequently pivoted such that the two protective cap parts 11a and 11b enclose the pump cylinder head 3 in ring-shaped fashion. Here, a detent hook 14 formed on the protective cap part 11a engages into a detent groove 15 formed on the protective cap part 11b (see FIG. 10b).

(22) The two protective cap parts 11a and 11b illustrated in FIG. 10 together form a domed projection 17. For this purpose, they have in each case one domed projection part 18a and 18b respectively. If no domed projection 17 is required, the two protective cap parts 11a and 11b may also be formed without domed projection parts 18a and 18banalogously to the embodiment illustrated in FIG. 1.