FUEL RAIL

Abstract

A fuel rail includes a pressure accumulator pipe which is configured to receive fuel under pressure and includes a forged tubular body. Made in one piece with the tubular body is an injector mount. A support arranged on the tubular body extends in alignment with the injector mount, with a screw fastener configured to secure the pressure accumulator pipe via the support to a cylinder head of an internal combustion engine.

Claims

1. A fuel rail, comprising: a pressure accumulator pipe configured to receive fuel under pressure and including a forged tubular body; an injector mount made in one piece with the tubular body; a support arranged on the tubular body in alignment with the injector mount; and a screw fastener configured to secure the pressure accumulator pipe via the support to a cylinder head of an internal combustion engine.

2. The fuel rail of claim 1, wherein the support has a shank extending from the tubular body and having a cylinder-head proximal end, and a flange provided at the end and having a passageway for passage of the screw fastener to secure the pressure accumulator pipe to the cylinder head.

3. The fuel rail of claim 1, wherein the support has a recess extending in a longitudinal direction of the support.

4. The fuel rail of claim 2, wherein the shank of the support has a recess extending in a longitudinal direction of the support.

5. The fuel rail of claim 2, wherein the flange has a cylinder-head distal side formed with an abutment surface for a screw head of the screw fastener.

6. The fuel rail of claim 2, wherein the flange has a support surface shaped to conform to an outer contour of the cylinder head.

7. The fuel rail of claim 1, wherein the screw fastener defines a screw-connection axis in longitudinal direction of the screw fastener, said support defining a longitudinal axis which extends at an oblique angle in relation to the screw-connection axis.

8. The fuel rail of claim 7, wherein the flange has a support surface shaped to conform to an outer contour of the cylinder head, said screw-connection axis and said longitudinal axis of the support intersecting at an intersection point, said intersection point lying on the support surface.

9. The fuel rail of claim 1, wherein the support defines a longitudinal axis which intersects a center longitudinal axis of the tubular body.

10. The fuel rail of claim 1, wherein the support has a width, measured transversely a center longitudinal axis of the tubular body, said tubular body defined by a diameter, measured transversely the center longitudinal axis of the tubular body, the width of the support being smaller than the diameter of the tubular body.

11. The fuel rail of claim 1, wherein the support is arranged in a longitudinal direction of the tubular body between two of said injector mount.

12. The fuel rail of claim 1, further comprising a coupling piece made of a same material as the tubular body and in one piece with the tubular body for securing an attachment piece.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0023] Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which:

[0024] FIG. 1 is a perspective illustration of a fuel rail according to the present invention;

[0025] FIG. 2 is a perspective illustration of the fuel rail of FIG. 1, mounted to a schematically depicted cylinder head;

[0026] FIG. 3 is a side view of the fuel rail of FIG. 2; and

[0027] FIG. 4 is a vertical section through the fuel rail in a region of a support.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] Throughout all the figures, same or corresponding elements may generally be indicated by same reference numerals. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way. It should also be understood that the figures are not necessarily to scale and that the embodiments may be illustrated by graphic symbols, phantom lines, diagrammatic representations and fragmentary views. In certain instances, details which are not necessary for an understanding of the present invention or which render other details difficult to perceive may have been omitted.

[0029] Turning now to the drawing, and in particular to FIG. 1, there is shown a perspective illustration of a fuel rail according to the present invention, generally designated by reference numeral 1. The fuel rail 1 is a component of an accumulator injection system of a combustion engine. Pressure generation and fuel injection are decoupled from one another in such an accumulator injection system. A separate high pressure pump produces pressure continuously. This pressure, generated regardless of the injection sequence, is permanently available in the fuel rail.

[0030] The fuel rail 1 includes a pressure accumulator pipe 2 with a pump-side fuel inlet 3 and several injector mounts 4, 5. Statically compressed fuel is stored in the pressure accumulator pipe 2 and supplied via the injector mounts 4, 5 to the injectors of a cylinder bank.

[0031] The pressure accumulator pipe 2 includes a forged tubular body 6. A longitudinal hollow space 7, shown in FIG. 4, is formed in the tubular body 6 by a deep drilling process. A plug 8 closes an end of the tubular body 6. Formed of same material by forging on the tubular body 6 is a neck-shaped mount 9 for installation of a pressure sensor. Also the neck-shaped fuel inlet 3 is formed of same material by being forged in one piece on the tubular body 6, thereby producing the forging blank which is then mechanically treated to provide i.a. connection openings or bores in the injector mounts 4, 5, in the fuel inlet 3, and the mount 9.

[0032] The fuel rail 1 is secured and mounted to the cylinder head 10 (FIG. 2) of a motor vehicle via supports 11 which are formed in one piece from the tubular body 6 and made of same material as the tubular body 6. FIGS. 1 and 2 show the provision of two supports 11 by way of example.

[0033] The supports 11 extend in a same direction as the injector mounts 4, 5 and are arranged in alignment with the injector mounts 4, 5 in longitudinal direction LR of the tubular body 6. Each support 11 is arranged between two of the injector mounts 4, 5. When viewing the pressure accumulator pipe 2 from an end, as shown in FIGS. 3 and 4, the longitudinal axes L1 of the supports 11 and the longitudinal axes L2 of the injector mounts 4, 5 coincide.

[0034] The aligned and parallel arrangement of the supports 11 and the injector mounts 4, 5 simplifies production of the tubular body 6 by forging. The supports 11 and the injector mounts 4, 5 are arranged together in the parting plane of a forging tool or forging tool halves and oriented in a same direction. This mitigates any risk of tool breakage or tearing or folding in the forged supports 11.

[0035] Each support 11 has a shank 12 which extends from the tubular body 6, and a flange 14 at a cylinder-head-proximal end 13 of the shank 12. The flange 14 has a passageway 15 for passage of a screw fastener 16. A recess 17 is provided in each of the supports 11 or their shank 12 and extends in longitudinal direction of the support 11. The recess 17 is machined by milling into the supports 11.

[0036] The flange 14 has a side distal to the cylinder head 10, which side has an abutment surface 18 for screw heads 19 of the screw fasteners 16. In addition, the flange 14 has on a cylinder-head-proximal side a support surface 20 which conforms to an outer contour of the cylinder head 10, as shown in FIGS. 3 and 4. The flange 14 bears with its support surface 20 upon the cylinder head 10.

[0037] Short screw fasteners 16 can be used to mount and secure the fuel rail 1 to the cylinder head 10. As a result, resiliency of the screw fasteners 16 and thus of the screw connection as a whole is decreased. The screw fasteners 16 are threadably engaged via the recess 17 and the passages 15 into corresponding threaded bores in the cylinder head 10. The screw heads 19 contact hereby upon the abutment surface 18 of the flange 14.

[0038] The support surface 20 of the flange 14 has in particular a slanted configuration. As a result, the contact area between the flange 14 and the cylinder head 10 can hereby be enlarged to thereby decrease surface pressure. The outer contour of the cylinder head 10 is slantingly inclined correspondingly in the attachment region of the fuel rail 1.

[0039] The screw-connection axis L3, extending in longitudinal direction of a screw fastener 16, and the longitudinal axis L1 of a support 11 extend at an oblique angle relative to one another. In addition, the screw-connection axis L3 and the longitudinal axis L1 of the support 11 intersect at an intersection point SP which lies in the plane of the support surface 20. The geometric configuration of the pressure accumulator pipe 2 is dimensioned such that the longitudinal axes L1 of the supports 11 intersect the center longitudinal axis MLA of the tubular body 6.

[0040] Threaded engagement and securement of the pressure accumulator pipe 2 to the cylinder head 10 via the screw fasteners 16 is implemented via the flanges 14 of the supports 11 below the tubular body 6. The width b1 of a support 11, as measured transversely to the center longitudinal axis MLA of the tubular body 6, is smaller than the diameter dl of the tubular body 6, as measured transversely to the longitudinal axis L4 of the tubular body 6.

[0041] Further formed in one piece on the tubular body 6 and made of same material as the tubular body 6 are coupling pieces 21 for securement of attachment parts. The coupling pieces 21 are provided for attachment of sleeves 22, as shown by way of example in FIG. 2. The sleeves 22 are configured to allow passage of screw fasteners 23, via which further attachment components can be mounted to the fuel rail 1.

[0042] While the invention has been illustrated and described in connection with currently preferred embodiments shown and described in detail, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit and scope of the present invention. The embodiments were chosen and described in order to explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.

[0043] What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims and includes equivalents of the elements recited therein: