GB2310891A

GB2310891A - Fuel feed connection

Info

Publication number: GB2310891A
Application number: GB9702682A
Authority: GB
Inventors: Manfred Mack
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1996-03-06
Filing date: 1997-02-10
Publication date: 1997-09-10
Anticipated expiration: 2017-02-10
Also published as: JPH09242643A; FR2745851B1; DE19608574A1; GB2310891B; GB9702682D0; KR970066066A; KR100480399B1; FR2745851A1

Description

2310891 1 Fuel feed device

Background art

The invention proceeds from a fuel feed device, in particular for a fuel injection valve miserted into a cylinder head of an internal combustion engine, according to the preamble of claim 1. Such a fuel feed device known from EP 0 569 727 B 1 comprises a pipe socket which projects into a passage of a cylinder head. The pipe socket at its inlet-side end of the high-pressure bore has a high-pressure connection, to which a highpressure fine leading from a high-pressure source, e.g. an injection pump, may be connected. At its outlet-side end, the pipe socket has a sealing surface, with which it is braced axially against a conical seat on the retaining body of the fuel injection valve.

The known pipe socket is braced against the fuel injection valve by means of a union nut, which embraces the pipe socket and is screwed into the through-bore of the cylinder head. At the inlet-side end of the pipe socket projecting axially out of the through-bore of the cylinder head, the high-pressure Iffle is connected by a flirther union nut to the highpressure connection.

The known fuel feed device does however have the drawback that the nature of the fasteming of the pipe socket by union nut does not allow a high tolerance compensation in the possible event of an axial or angular nuisalignment of the pipe socket relative to the through-bore in the cylinder head and relative to the seat on the fuel injection valve. The unii on nut moreover requires the through-bore in the cylinder head to have a large diameter which, mi modem i. c. engines, is often not available.

Advantages of the ffivention 2 In contrast, the fuel feed device according to the invention having the characterizing features of claim 1 has the advantage that the pipe socket is braced axially against the conical seat of the injection valve by means of a fastening flange which is disposed outside of the through-bore.

Said fastening flange, which preferably takes the form of an annular flange, enables the through-bore in the cylinder head to have a smaller diameter, the necessary axial pressure against the pipe socket being reliably guaranteed by the at least two fastening screws which are screwed radially outwards of the throughbore into the cylinder head. An alternative possibility is a greater number of fastening screws on the annular flange, which are then arranged uniformly distributed over the periphery.

It is moreover possible, mi said manner, to shorten the length of the pipe socket and of the through-bore, which again reduces the installation space required.

To enable maximum compensation for play in the event of an axial or angular misalignment of the pipe socket relative to the through-bore and/or the seat, the contact surface on the annular flange is conical and the annular shoulder, which cooperates with said contact surface, and the outlet-side sealing surface of the pipe socket are spherical, preferably being curved spherically outwards. An alternative possibility might be to provide the spherical surfaces on the seat and/or on the annular flange.

Play is simultaneously provided between the stem of the pipe socket and the wall of the through-bore and between the annular flange and the cylinder head, which play enables a specific axial and/or angular misalignment of the pipe socket.

The fuel feed device according to the invention is particularly suitable for the 3 connection to a fuel injection valve inserted into the cylinder head of an i. c. engine but may alternatively be used for the connection to similar structural parts such as, for example, fuel pumps.

Further advantages and advantageous refinements of the subject matter of the invention are indicated in the description, the drawings and the claims.

Drawings An embodiment of the fuel feed device according to the invention is illustrated in the drawings and explained in detail in the following description. Of the drawings, Figure 1 is a section through the feed device inserted into a cylinder head of an i.c. engine and Figure 2 is a simplified plan view of the annular flange according to Figure 1.

Description of the embodiment

In the embodiment of the fuel feed device according to the invention which is illustrated in Figure 1, in a cylinder head 1 of an i.c. engine a known fuel injection valve, of which only a part of the valve-retaining body 5 is shown in Figure 1, is inserted into a bore 3 which opens into the combustion chamber of the i. c. engine. For fuel supply purposes, the valve-retaining body 5 of the injection valve has a radial bore 7, the outlet opening of which forms a conical or tapered seat 9. Disposed in alignment with said seat 9 in the cylinder head 1 is a passage in the form of a stepped through-bore 11, into which a pipe socket 13 projects. The outlet-side end of the pipe socket 13 adjacent to the seat 9 forms a sealing surface 14, which is curved sphenically outwards and cooperates with the conical seat 9. The pipe socket 13 is axially penetrated by a high-pressure bore 15 having an enlargement in tile inlet-side end portion 17, into which enlargement a known rod- 4 shaped fuel filter 19 is inserted.

On the peripheral surface of the inlet-side end portion 17 an annular step 21 formed by a cross-sectional enlargement is further provided, which with its annular end face projecting from the through-bore 11 forms an annular shoulder 23 which is curved spherically outwards. An annular flange 25 is applied by an annular contact surface 29, which is provided at its end face 27 directed towards the cylinder head 1 and is conical, against said annular shoulder 23. The annular flange 25 has a central, axial through-opening 3 1, which is surrounded by the contact surface 29 and through which the pipe socket 13 projects with its inlet-side free end. For axial bracing of the pipe socket 13 against the seat 9 the annular flange 25, as Figure 2 reveals, has two location holes 35, inserted into which are two fastening screws 33, which are applied with their head against the end face of the annular flange 25 remote from the cylinder head 1 and are screwed with their firee ends into corresponding threads 37 in the wall of the cylinder head 1.

Disposed on the inlet-side end of the pipe socket 13 projecting out of the annular flange 25 is an external thread 39, onto which is screwed a union nut 41 which presses a tapered connection piece 43 of a feed pipe 45 against a conical highpressure connection surface 47 at the inlet of the high-pressure bore 15. A sealing ring 5 1, which is inserted into a peripheral groove 49 of the annular step 21 and lies with its outside against the wall of the through-bore 11, seals off a leakage oil chamber 53 formed between the pipe socket 13 and the wall of the through-bore 11 from the outside.

The spherical contact surfaces between the seat 9 and the sealing surface 14 of the pipe socket 13 as well as between the annular shoulder 23 of the pipe socket 13 and the contact surface 29 of the annular flange 25 enable a high degree of compensation for play in the event of an axial and/or angular misalignment of the pipe socket 13, which is additionally assisted by the provision of play of the pipe socket 13 in the through-bore 11 and between the end face 27 of the annular flange 25 and the cylinder head wall.

6

Claims

1.

2.

3.

4..

5.

Fuel feed device, m particular for a fuel injection valve inserted into a cylinder head (1) of an internal combustion engine, comprising a pipe socket (13), which penetrates a passage (11) in the cylinder head (1) and at its inlet-side end of a high-pressure bore (15) has a high-pressure connection (47) and at its outlet-side is braced with a sealing surface (14) axially against a conical seat of an intake in the (9) retaining body (5) of the fuel injection valve, characten A zed in that the pipe socket (13) is braced by means of a fastening flange axially against the conical seat (9) on the retaining body (5).

Fuel feed device according to claim 1, characterized in that the fastening flange takes the form of an annular flange (25).

Fuel feed device according to claim 1, characterized in that the pipe socket (13) at its inlet-side end has an annular shoulder (23), which is formed by a diameter enlargement and against which the fastening flange is applied.

Fuel feed device according to claims 2 and 3, characterized in that the annular flange (25) at its end face (27) directed towards the cylinder head (1) has an annular contact surface (29), which adjoins an axial through-opening (3 1) for the pipe socket ( 13) in the annular flange (25) and with which the annular flange (25) is applied against the annular shoulder (23) of the pipe socket (13).

Fuel feed device according to claim 4, characterized mi that the annular shoulder (23) on the pipe socket (13) is spherical, preferably 7 being curved outwards as part of a spherical surface, and the contact surface (29) on the annular flange (25) which cooperates with said annular shoulder is conical.

6.

7.

8.

9.

Fuel feed device according to claim 1, characterized in that the sealing surface (14) at the outlet-side end of the pipe socket (13) which cooperates with the conical seat (9) is spherical, preferably being curved outwards as part of a spherical surface.

Fuel feed device according to claim 2, characterized in that the annular flange (25) has at least two location holes (35) for receiving fastening screws (33), which are screwed by their free ends into corresponding threads (37) of the cylinder head (1).

Fuel feed device according to claim 2, characterized in that a specific clearance is provided between an end face (27) of the annular flange (25) directed towards the cylinder head (1) and the wall of the cylinder head (1).

A fuel feed device substantially as herein described with reference to the accompanying drawing