GB2310892A

GB2310892A - I.c engine fuel injection valve fuel supply device with integrated leakage oil discharge

Info

Publication number: GB2310892A
Application number: GB9702694A
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: JPH09242642A; GB2310892B; GB9702694D0; FR2745850A1; DE19608572A1

Description

2310892 1 Fuel supply device State of the art The invention proceeds from

a fuel supply device, in particular for a fuel injection valve fitted in a cylinder head of an internal combustion engine according to the generic type of claim 1. A fuel supply device of this type known from EP 0 569 727 B 1 comprises a pipe socket which projects into a passage in a cylinder head. In this case, the pipe socket at its inflow end for a high pressure bore or high pressure line, comprises a high pressure connection, to which a high pressure fine leading from a high pressure source, e.g. an injection pump, can be connected. At its outflow end, the pipe socket comprises a sealing surface, by means of which the pipe socket is axially clamped against a conical seat on the retaining body of the fuel injection valve.

The known pipe socket is clamped against the fuel injection valve by means of a retaining nut which encloses the pipe socket and is screwed Mito the through bore of the cylinder head. At the inflow end of the pipe socket projecting axially from the through bore of the cylmider head, the high pressure line is connected to the high pressure connection by means of a finther retaining nut. The leakage oil discharge from a leakage oil chamber formed between the shaft of the pipe socket and the through bore of the cylinder head enclosing said shaft is effected mi a manner which is not flu-ther illustrated via an additional bore mi the cylinder head.

The known fuel supply device thus has the disadvantage of requiring additional machining of the cylinder head for the leakage oil discharge, which results in increased manufacturing costs. In addition, the axial connection of the high pressure line requires increased and geometrically fixed structural space on the internal combustion engine which is to be supplied. This space is only available to a limited degree in modem internal combustion engines.

Advantages of the invention in contrast, the fliel supply device according to the invention having the characterising features of claim 1 offers the advantage that the device for discharging the leakage oil is integrated in the pipe socket so that there is no need for additional bores and connections to the cylinder head of the internal combustion engine. To this end, a leakage oil bore is provided in the pipe socket in a structurally simple manner, leading from the leakage oil chamber between the pipe socket and the through bore and opening into a leakage oil connection socket on the pipe socket which can be constructed as a leakage oil connection pipe or as a screw connection socket.

In order to make room for the leakage oil connection socket, the inflow end of the pipe socket projecting out of the through bore in the cylinder head is angled in accordance with the invention, which offers the additional advantage of high flexibility in respect of the assembly position and the connection of the high pressure line. The connection socket of the leakage oil bore is fitted in the angled section of the pipe socket as a sninple axial extension of the leakage oil bore, so that additional cross bores or the like leading off from the leakage oil bore are unnecessary.

A flu-ther advantage is attained by the provision of a securing flange with tongues projecting radially from the pipe socket. Receiving bores are provided in said tongues for receiving securing screws, by means of which the pipe socket is axially clamped agamist the cylinder head. In this respect, the pipe socket rests with its sealing surface provided at its outflow end in a sealing-fight manner against a seat of the retaining body of the injection valve, the spherical or curved 3 sealing surface in association with the conical shape of the seat compensating any axial or angular displacement of the components within a given tolerance range.

This possible tolerance compensation is supported by the curved annular end face of the securing screws and the axial spacmig between the cylinder head wall and the flange, which thus also allows for a given displacement of the components relative to one another at the site where the fuel is introduced into the pipe socket.

The high pressure line extending in the angled, inflow end of the pipe socket is constructed in such a manner that a fuel filter constructed as a filter cartridge can be easily fitted in said high pressure line element from the high pressure connection.

The pipe socket fulfilling the various described flinctions is advantageously integrally formed with the securing flange and can be constructed as a forged part or rotationally symmetrical turned part, in which the free, inflow section can be subsequently bent as desired. In cases where the pipe socket is constructed as a turned part, the securing flange extends over the entire circumference of the pipe socket.

The fuel supply device according to the invention is suitable for connection to a fuel injection valve fitted in the cylinder head of an internal combustion engine. However, it can also be used on similar components, such as pumps.

Further advantages and advantageous developments of the subject matter of the invention will be clear from the description, the drawings and the claims.

Drawings 4 An embodinient of the fuel supply device according to the invention is illustrated m the drawhigs and explained in flirther detail m the following description. Figure 1 is a section through the pipe socket fitted in a cylinder head of an internal combustion engine and Figure 2 is a section through Figure 1 taken along line II-II.

Description of the embodiment

In the embodiment of the fuel supply device according to the invention illustrated in Figure 1, a known fuel injection valve is fitted mi a cylinder head 1 of an internal combustion engine in a bore 3 opening into the combustion chamber of said internal combustion engine. Only part of the valve retaining body 5 of said valve is illustrated in Figure 1. For the fuel supply, the valve retaining body 5 of the injection valve comprises a radial bore 7, whose outlet opening forms a conical seat 9. In alignment with this seat 9, a passage mi the form of a stepped through bore 11 is arranged 'm the cyl mider head 1, into which through bore a pipe socket 13 with a cylindrical shaft extension 15 projects. In this respect, the outflow end of the pipe socket 13 adjoining the seat 9 forms a sealing surface 17, which cooperates with the seat 9 and curves spherically outwards. The sealing surface 17 constructed as an annular surface radially defines a high pressure line 19, which penetrates the entire pipe socket 13, is preferably constructed as a high pressure bore and opens into the bore 7 in the valve retaining body 5.

Adjoining the cylindrical shaft 15 which tapers conically towards the seat 9, the pipe socket 13 comprises a central section 21 which has an enlarged diameter and projects out of the stepped through bore 11 of the cylinder head 1, an annular shoulder 23 being formed at the cross sectional transition to the shaft element 15. In this respect a leakage oil chamber 25 is formed in the cylinder head 1 between the circumferential wall of the pipe socket 13 and the wall of the through bore 11, said chamber being sealed towards the outside by means of a sealing ring 27 which is clamped between the circumferential wall of the central section 21 of the pipe socket 13 and the wall of the through bore 11. The sealing ring is guided in a circumferential groove 29 in the central section 21 of the pipe socket.

At its free, inflow end, the central section 1 of the pipe socket 13 adjoins a finiher tubular connecting section 3 1, whose diameter is reduced as compared with the central section and which is angled relative to the axis of the central section 21 and the shaft 15. The free, inflow end of this connecting section 31 comprises a high pressure connection 33), to which an injection line leading to a fliel injection pump can be connected. The cross section of the high pressure line 19 in the region of the connecting section 31 is enlarged as compared with the rem i 9 region and forms a filter chamber 35, into which a rod-shaped fuel filter can be inserted from the inflow end. The section of the high pressure line 19 forniing the filter chamber 35 extends into the section of the high pressure line 19 continuing m the shaft 15.

In order to secure the pipe socket 13 to the cylinder head 1. the pipe socket 13, as also shown in section m Figure 2, comprises a securing flange 37, which is formed by two securing tongues 39 projecting radially from the central section 21. Provided in each of the securing tongues 39 is a receiving bore 41 for a securing screw 43, which are screwed into corresponding threaded bores in the wall of the cylinder head 1 and thus clamp the pipe socket 13 with its sealing surface 17 in an axially sealing-tight manner against the valve retaining body 5. In order to compensate possible angular displacement, the annular end faces 45, which are formed between the shaft and the head of the securing screws 43 and which rest against the flange 37, curve spherically outwards and are guided in corTesponding recesses in the securing tongues 39. In addition, a specific gap is provided between the end face of the securing flange 3 7 facing the cylinder head 1 and the wad of the cylinder head 1, which gap allows for an angular displacement of the 6 pipe socket 13 within given limits.

In order to discharge the leakage oil from the leakage oil chamber 25, a leakage oil bore 47 is provided in the pipe socket 13, which penetrates the pipe socket 13 axially and extends between the high pressure line 19 and the circumferential groove 29, as also shown in Figure 2. This leakage oil bore 47 extends from the annular shoulder 23 and opens into a leakage oil socket 49, which is fitted in the angled part of the connecting section 31 of the pipe socket 13 and to which a leakage oil outflow line can be connected.

The described pipe socket 13 is integrally formed with the shaft 15, the central section 21, the angled connecting section 31 and the securing flange 37, and is preferably constructed as a forged part.

With the fuel supply device according to the invention it is therefore easily possible from a design point of view to integrate the various flinctions, such as high pressure sealing and connections, filter accommodation, securing with tolerance compensation and leakage oil sealing and discharge in a single component, so that the need for additional components is dispensed with.

7

Claims

A fuel supply device, in particular for a fuel injection valve fitted in a cylinder head (1) of an internal combustion engine, with a pipe socket (13), which penetrates a passage (11) in the cylinder head (1), comprises a high pressure connection (33) at its inflow end for a high pressure line (19) and at its outflow end is clamped axially with a sealing surface (17) against a conical seat (9) of an inflow in the retaining body (5) of the fuel injection valve, characterised in that means for leakage oil discharge is provided in the pipe socket (13).
2. A fuel supply device according to claim 1, characterised in that means for leakage oil discharge in the pipe socket (13) is formed by a leakage oil bore (47), which leads from a leakage oil chamber (25) formed in the passage (11) in the cylinder head (1), extends from an annular shoulder (23) on the pipe socket (13) closing the passage (11) and opens into a leakage oil socket (49) fitted in the pipe socket (13).
3. A fuel supply device according to claim 2, characterised m that the pipe socket (13) is angled at its inflow end (3 1) projecting from the cylinder head (1), the leakage oil socket (49) being provided as an axial extension of the leakage oil bore (47) mi the knee of the angled section (3 1) of the pipe socket (13).
4. A fuel supply device according to claim 2, characterised in that the leakage oil. chamber (25) formed mi the cylinder head (1) between the shaft (15) of the pipe socket (13) and the wall of the passage (11) is sealed by a sealing ring (27) fitted in this region between a section (2 1) of the pipe socket (13) having an enlarged diameter and the wall of the passage (11).

8
5. A fuel supply device according to claim 4, characterised in that the sealing ring (27) is guided in a radial circumferential groove (29) in the section (3 1) of the pipe socket (13) having an enlarged diameter.
6. A fuel supply device according to claim 1, characterised in that a securing flange (37) is provided on the pipe socket (13), the tongues (39) of said flange, of which there are preferably two, projecting radially beyond the pipe socket (13, 21) and each comprising a receiving bore (41) for a securing screw (43).
7. A fuel supply device according to claim 6, characterised mi that the end faces of the tongues (39) facing the cylinder head (1) are arranged at a given distance firom the wall of the cylinder head (1).
8. A fuel supply device according to claims 1 to 6, characterised in that the securing flange (37) is integrally formed with the pipe socket (13), and the leakage oil bore (47) is arranged between the high pressure Iffle (19) and the radial circumferential groove (29) of the pipe socket (13).
9. A fuel supply device according to claim 7, characterised in that the annular end face (45), formed between the shaft and the head, of the securing screws (43) which are inserted into the receiving bore (4 1) of the securing flange (37) and are screwed mito the wall of the cylinder head (1), is curved spherically outwards.
10. A fuel supply device according to claim 3, characterised in that a fuel filter is fitted in the high pressure line (19) in the angled, inflow section (3 1) of the pipe socket (13).

9
11. A fuel supply device according to claim 1, characterised in that the cylindrical pipe socket shaft (15) projecting into the passage (11) in the cylinder head (1) tapers conically towards the outflow end.
12. A fuel supply device according to claim 1, characterised in that the annular sealing surface (17) arranged at the outflow end of the pipe socket (13, 15) curves spherically outwards.
13. A fuel supply device according to claim 1, characterised in that the pipe socket (13) is constructed together with the securing flange (3 7) as an integral forged part.
14. A fuel supply device according to claim 1 and 3, characterised in that the pipe socket (13) is constructed with the securing flange (37) as a rotationally symmetrical turned part whose inflow section (3 1) comprising the high pressure connection (J3)"i) is bent following the turning process.
15. A fuel supply device substantially as herein described with reference to the accompanying drawings.