GB2416373A

GB2416373A - Fuel feed for an internal combustion engine with direct injection

Info

Publication number: GB2416373A
Application number: GB0510610A
Authority: GB
Inventors: Ingo Lausen; Cornelius Josephus Adri Deelen
Original assignee: Benteler Automobiltechnik GmbH
Current assignee: Benteler Automobiltechnik GmbH
Priority date: 2004-07-22
Filing date: 2005-05-24
Publication date: 2006-01-25
Anticipated expiration: 2025-05-24
Also published as: GB0510610D0; GB2416373B; DE102004035645B4; DE102004035645A1

Abstract

The fuel feed (1) for an internal combustion engine has a feed line (3) comprising a plurality of pipe sections (2). A branch (4) designed for mounting on the engine housing, in which connecting passages (5, 6) for transferring fuel from the feed line (3) to a fuel injection unit are provided, is installed in the joint area (10) of two pipe sections (2). The branch (4) is an integral part of the pipe section (2) at a first end (6). At this point, the pipe section (2) has a connecting piece (8) of a smaller diameter, the outer diameter (AD) of which is matched to the inner diameter (ID) of the pipe section (2) at the other end (9). The pipe section (2) and the branch (4) are integrally cast from stainless steel.

Description

241 6373 Fuel Feed for an Internal Combustion Ennine with Direct Iniection

The invention relates to a fuel feed for an internal combustion engine with direct injection.

A fuel feed of this type represents prior art owing to the disclosed content of DE 199 53 942 C2. It comprises a feed line consisting of a plurality of pipe sections. Adjacent end faces of adjoining pipe sections are arranged at a distance from one another. These areas are covered by sleeve-like branches which may be made of a light alloy such as aluminium or of plastic. The pipe sections are made of aluminium, steel or plastic.

At the end of each branch, diagonally opposite mounting eyes with parallel through holes are provided. By means of these mounting eyes, the branches can be secured to the engine housing. In addition to the two mounting eyes, a side arm featuring a blind hole is provided approximately half-way along the length of each branch. Via an inclined bore, this blind hole is connected to the area located within the branch between the two end faces of adjacent pipe sections. The feed line is connected to a fuel injection unit via the blind hole and the inclined bore. The inclined bore runs in a transverse plane offset by 90 relative to a plane intersecting the longitudinal axis of the feed line.

The number of branches corresponds to the number of cylinders of the internal combustion engine. The free ends of the feed line may be sealed by caps, and these end caps may incorporate connections, for instance to a high-pressure fuel line or to a high-pressure sensor.

The known fuel feed has many parts and is comparatively large in the area of the branches, because the ends of the pipe sections of the feed line are located within the branches. This involves relatively high manufacturing costs.

In addition, each branch has diagonally opposite mounting eyes at its ends, requiring an even larger installation volume.

On the basis of prior art, the invention is based on the problem of creating a fuel feed for an internal combustion engine with direct injection, which is constructed more compactly and easier to produce without reducing the proportion of fuel in the feed line.

This problem is solved by the features specified in claim 1.

According to this, each pipe section has a connecting piece of a smaller diameter at a first end. The outer diameter of the connecting piece is matched to the inner diameter of the pipe section at its other, second end. As a result, the connecting piece at one pipe section fits tightly into the second end of a further pipe section when two pipe sections are connected to one another.

The end faces of the pipe sections at the second end contact annular end faces on the circumference of the connecting pieces. In this way, the entire feed line is given an even external contour virtually free of any projections.

The invention offers the further advantage that both the transfer of highpressure fuel to the fuel injection unit and the location of the branch on the engine housing are exclusively confined to the branch. This further enhances the compact design of the unit while maintaining a maximum flow cross- section for the fuel. The number of individual components is significantly reduced by the integral design of pipe section and branch. This also reduces tolerance problems and the risk of leakage.

To prevent the widening of the gap between a connecting piece and a pipe section by the pressure of the fuel, the wall thickness of the connecting piece is less than the wall thickness of the second end. It then appears to be expedient to join the overlapping area of the connecting piece to the second end by brazing. However, other suitable joining methods ensuring a leak- proof joint area between two pipe sections can be used.

The flow of fuel from one pipe section to the adjacent pipe section is improved by providing that the longitudinal passage in the connecting piece extends towards the end face of the connecting piece in a conically widening opening. As a result, the flow resistance due to the engagement between a connecting piece and the second end of a pipe sections is not increased significantly.

Each pipe section made even more compact by designing the branch as a lateral connecting bracket in which both the connecting passages and a mounting hole for securing the branch to the housing are formed.

The connecting passages are represented by a blind hole in the branch and an inclined bore connecting the blind hole to the longitudinal passage in the connecting piece. A transverse plane intersecting the axis of the blind hole extends immediately adjacent to the connecting piece. The inclined bore runs from the blind hole through an inclined transitional section between the branch and the connecting bracket. This, too, makes the branch even more compact. The axis of the inclined bore lies at an angle deviating from 90 both in relation to the axis of the blind hole and in relation to the axis of the longitudinal passage in the pipe section or branch.

The compact design of the branch is promoted further by providing that the axes of the blind hole and of the mounting hole lie in a plane which is parallel to a plane extending through the axis of the pipe section.

To ensure that the inclined bore between the longitudinal passage and the blind hole in the branch can be produced faultlessly and without difficulty, the axis of the inclined bore runs tangentially into the blind hole and intersects the opening of the connecting piece.

In view of the fact that the inclined bore is expediently produced by drilling, the inclined bore terminates in a projection extending into the longitudinal passage of the connecting piece, the end face of which extends at right angles to the axis of the inclined bore and faces the opening of the connecting piece. As a result, the use of a drill to produce the inclined bore does not involve any difficulties. In addition, flow conditions at the entry of fuel into the inclined bore are improved.

A further design of the branch area is that the connecting passages are represented by a blind hole in the branch and an inclined bore connecting the blind hole to an inner chamber of the branch open towards the longitudinal passage in the pipe section. The inner chamber increases the fuel capacity of the feed line.

The axis of the inclined bore is aligned between the blind hole and the opening of the pipe section at the second end. In this design, the fuel in the feed line preferably flows from the second end of a pipe section towards the connecting piece at the first end.

A further advantage is gained if the surface of the branch which lies opposite the openings of the blind hole and of the mounting hole lies approximately in a plane which also extends through the axis of the pipe section.

To avoid unnecessary material accumulations, the mounting hole is continued in a sleeve-like extension of the branch.

A further characteristic feature of the invention lies in the fact that the pipe section and the integral branch designed as a connecting bracket are stainless steel castings. Very close tolerances can be met in casting stainless steel. In addition, it is possible to produce the pipe section design with an inner chamber in the branch using a dead core. With this dead core, the inclined bore between the blind hole and the inner chamber can be produced simultaneously.

The anti-rotation element is in particular represented by an integral projection in the area between the blind hole and the mounting hole and acts together with a recess in the fuel injection unit (injector) to hold the injector in position.

In particular in SGDI (spray guided direct injection), the anti-rotation unit ensures that the spray pattern of the injector adopts a defined angle relative to the spark plug.

In order that the present invention may be more readily understood, embodiments thereof will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a horizontal axial section through a part of a fuel feed line to a fuel injection unit of an internal combustion engine with direct injection; Figure 2 is a front view of the illustration from Figure 1 in the direction of arrow 11.

Figure 3 is a side view of the illustration from Figure 1 in the direction of arrow 111.

Figure 4 is an illustration of a further embodiment similar to Figure 1.

Reference number 1 in Figure 1 identifies a section of a fuel feed for an internal combustion engine with direct injection, which is not shown in detail.

The fuel feed 1 has a feed line 3 comprising a plurality of pipe sections 2 (Figures 1 to 3). The fuel passes through this line in the direction STR. A branch 4 in the form of a connecting bracket designed for mounting on the housing of the internal combustion engine is integrated with each pipe section 2. The pipe section 2 and the branch 4 are stainless steel castings.

Connecting passages 5, 6 for transferring fuel from the feed line 3 to a fuel injection unit are provided in the branch 4. The number of branches 4 on the pipe sections 2 corresponds to the number of cylinders of the internal combustion engine.

Each pipe section 2 has a connecting piece 8 of a smaller diameter at a first end 7. Its outer diameter AD matches the inner diameter ID of the pipe section 2 at the other, second end 9. In this way, two pipe sections 2 can be directly pushed together axially in the joint area 10 to form a seal. The second end 9 of a pipe section 2 then encloses the connecting piece 8 at the first end 7 of the next pipe section 2. The end face 11 of the second end 9 of the pipe section 2 comes into contact with an annular end face 12 on the circumference of the connecting piece 8.

The wall thickness WD of the connecting piece 8 is less than the wall thickness WD1 at the second end 9 of the pipe section 2.

The longitudinal passage 13 in the connecting piece 8 extends towards the end face 15 of the connecting piece 8 in a conically widening opening 14.

The connecting passages 5, 6 are represented by a blind hole 5 in the branch 4 and an inclined bore 6 connecting the blind hole 5 to the longitudinal passage 13 in the connecting piece 8. The axis 16 of the inclined bore 6 extending tangentially into the blind hole 5 intersects the opening 14 of the connecting piece 8. The axis 16 of the inclined bore 6 runs at an angle deviating from 90 in relation both to the axis 17 of the blind hole 5 and to the axis 18 of the pipe section 2.

The inclined bore 6 terminates in a projection 19 extending into the longitudinal passage 13 of the connecting piece 8. Its end face 20 lies at right angles to the axis 16 of the inclined bore 6 and faces the opening 14 of the connecting piece 8.

The branch 4 incorporates a mounting hole 22, the axis 21 of which runs parallel to the axis 17 of the blind hole 5.

The axes 17, 21 of the blind hole 5 and the mounting hole 22 lie in a common plane E- E which lies parallel to a plane E' - E' extending through the axis 18 of the pipe section 2.

The surface 25 of the branch 4, which lies opposite the openings 23, 24 of the blind hole 5 and the mounting hole 22 respectively, extends approximately in a plane E2 - E2, which also extends through the axis 18 of the pipe section 2.

The mounting hole 22 is continued in a sleeve-like extension 26 of the branch 4.

Figure 4 shows a design of a pipe section 2a which in principle corresponds to the design of Figures 1 to 3. This means that two pipe sections 2a can be tightly pushed together using a connecting piece 8 at the first end 7 and the second end 9. The pipe section 2a also features a branch 4a in the form of an integral connecting bracket. The pipe section 2a and the branch 4a are stainless steel castings.

The connecting passages 5, 6a of this design are represented by a blind hole in the branch 4a and an inclined bore 6a connecting the blind hole 5 to an inner chamber 28 of the branch 4a, which is open towards the longitudinal passage 27 in the pipe section 2a. The axis 29 of the inclined bore 6a is aligned between the blind hole 5 and the opening 30 of the pipe section 2a at the second end 9. The fuel flows in the direction indicated by arrow STR1.

Both in the design of Figures 1 to 3 and in the design of Figure 4, the branch 4, 4a is provided with an anti-rotation element 31 in the form of an integral projection in the area between the blind hole 5 and the mounting hole 22. The anti-rotation element acts together with a recess in a fuel injection unit (injector) to hold the injector in its position. As a result, it can be ensured - in particular in SGDI (spray guided direct injection) - that the spray pattern of the injector always adopts a defined angle relative to a spark plug.

Reference Numbers 1 - Fuel feed 2 - Pipe section 2a - Pipe section 3 Feed line 4 - Branch 4a - Branch - Blind hole 6 - Inclined bore 6a Inclined bore 7 - First end of 2 8 - Connecting piece on 7 9 - Second end of 2 - Joint area of 2 1 1 - End face of 9 12 - End face 13 - Longitudinal passage in 8 14 - Opening of 8 1 5 - End face of 8 16 - Axis of 6 17 Axis of 5 18 - Axis of 2 19 - Projection in 13 - End face of 19 21 - Axis of 22 22 - Mounting hole in 4, 4a 23 - Opening of 5 24 - Opening of 22 Surface of 4 26 - Extension of 4, 4a 27 - Longitudinal passage in 2a 28 Inner chamber in 4a 29 - Axis of 6a - Opening of 9 31 - Anti-rotation element AD - Outer diameter of 8 ID - Inner diameter of 2, 2a E-E - Plane through 17, 21 E,-E, - Plane through 18 STR - Direction of flow STR' Direction of flow WD - Wall thickness of 8 WD' - Wall thickness of 2, 2a

Claims

Claims: 1. A fuel feed for an internal combustion engine with direct

injection, the feed comprising a pipe section integrally formed with a branch for mounting on an engine housing, the feed having a connecting piece at one end to fit inside the other end of another such fuel feed or a pipe section.
2. A fuel feed according to Claim 1, wherein the branch is installed in a joint area of two pipe sections.
3. A fuel feed according to Claim 1 or 2, wherein connecting passages for transferring fuel from the feed to a fuel injection unit are provided.
4. A fuel feed according to any preceding claim, wherein the branch is located at the end of the pipe section having the connecting piece.
5. A fuel feed according to any preceding claim, wherein an outer surface of the connecting piece at one end of the feed matches an inner surface of the pipe section at the other end of the feed such that the connecting piece can fit inside the other end of another such fuel feed or a pipe section.
6. A fuel feed according to Claim 5, wherein the outer diameter (AD) of the connecting piece matches the inner diameter (ID) at the other end of the feed.
7. A fuel feed according to any preceding claim, wherein the wall thickness (WD) of the connecting piece is less than the wall thickness (Wry) at the other end of the feed.
8. A fuel feed according to claim 1 or 2, wherein a longitudinal passage in the connecting piece extends towards the end face of the connecting piece in a conically widening opening.
9. A fuel feed according to any preceding claim, wherein the branch is designed as a lateral connecting bracket in which both the connecting passages and a mounting hole are provided.
10. A fuel feed according to claim 9, wherein the connecting passages are represented by a blind hole in the connecting bracket and an inclined bore connecting the blind hole to the longitudinal passage in the connecting piece.
11. A fuel feed according to claim 10, wherein the axes of the blind hole and the mounting hole lie in a common plane (E - E) which lies parallel to a plane (E' - E') extending through the axis of the longitudinal passage in the pipe section.
12. A fuel feed according to claim 10 or 1 1, wherein the axis of the inclined bore runs tangentially into the blind hole and points towards and passes through the opening of the connecting piece.
13. A fuel feed according to any of claims 10 to 12, wherein the inclined.

bore terminates in a projection located in the longitudinal passage of the connecting piece, the end face of which extends at right angles to the axis of the inclined bore and faces the opening of the connecting piece.
14. A fuel feed according to any of claims 1 to 9, wherein the connecting passages are represented by a blind hole and an inclined bore connecting the blind hole to an inner chamber of the branch, which is open towards the longitudinal passage in the pipe section.
15. A fuel feed according to claim 14, wherein the axis of the inclined bore is aligned between the blind hole and the opening of the pipe section at the other end to the connection piece.
16. A fuel feed according to any preceding claim, wherein the surface of the connecting bracket which lies opposite the openings of the blind hole and the mounting hole lies approximately in a plane (E2 - E2), which also extends through the axis of the pipe section.
17. A fuel feed according to any of claims 9 to 16, wherein the mounting hole (22) is continued in a sleeve-like extension (26) of the branch (4, 4a).
18. A fuel feed according to any preceding claim, wherein the pipe section and the branch are stainless steel castings.
19. A fuel feed according to any preceding claim, wherein an antirotation element is provided on the branch. , l; i i;
20. A fuel feed substantially as hereinbefore described with reference to >' and as shown in the accompanying drawings. ' Id; ) \, \, i) ) i i ) 1;

19. A fuel feed according to any preceding claim, wherein an antirotation element is provided on the branch.

20. A fuel feed substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

21. Any novel feature or combination of features disclosed herein.

Amendments to the claims have been filed as follows Claims: 3 1. A fuel feed for an internal combustion engine with direct injection, the feed comprising a pipe section Integrally formed with a branch in the form of a connecting bracket designed for mounting on an engine housing, the feed having a connecting piece at one end to fit inside the other end of another such pipe section.

2. A fuel feed according to Claim 1, wherein the branch is installed in a joint area of two pipe sections.

3. A fuel feed according to Claim 1 or 2, wherein connecting passages for, . transferring fuel from the feed to a fuel injection unit are provided. . 4. A fuel feed according to any preceding claim, wherein the branch is, located at the end of the pipe section having the connecting piece. , l..

5. A fuel feed according to any preceding claim, wherein an outer surface 2''' of the connecting piece at one end of the feed matches an inner surface of a' the pipe section at the other end of the feed such that the connecting piece can fit inside the other end of another such pipe section.

6. A fuel feed according to Claim 5, wherein the outer diameter (AD) of the connecting piece matches the inner diameter (ID) at the other end of the feed.

7. A fuel feed according to any preceding claim, wherein the wall thickness (WD) of the connecting piece is less than the wall thickness (Wed at the other end of the pipe section.

8. A fuel feed according to claim 1 or 2, wherein a longitudinal passage in the connecting piece extends towards the end face of the connecting piece in a conically widening opening.

9. A fuel feed according to claim 3, wherein the branch is designed as a lateral connecting bracket in which both the connecting passages and a mounting hole are provided.

10. A fuel feed according to claim 9, wherein the connecting passages are represented by a blind hole in the connecting bracket and an inclined bore connecting the blind hole to the longitudinal passage in the connecting piece.

11. A fuel feed according to claim 10, wherein the axes of the blind hole and the mounting hole lie in a common plane (E - E) which lies parallel to a plane (El - El) extending through the axis of the longitudinal passage in the.

pipe section. -. . 12. A fuel feed according to claim 10 or 11, wherein the axis of the inclined r,' '''' bore runs tangentially into the blind hole and points towards and passes.. ,', through the opening of the connecting piece.

13. A fuel feed according to any of claims 10 to 12, wherein the inclined it bore terminates in a projection located in the longitudinal passage of the connecting piece, the end face of which extends at right angles to the axis of the inclined bore and faces the opening of the connecting piece.

14. A fuel feed according claim 9, wherein the connecting passages are represented by a blind hole and an inclined bore connecting the blind hole to an inner chamber of the branch, which is open towards the longitudinal passage in the pipe section.

15. A fuel feed according to claim 14, wherein the axis of the inclined bore is aligned between the blind hole and the opening of the pipe section at the other end to the connection piece.

16. A fuel feed according to any one of claims 9 to 15, wherein the surface of the connecting bracket which lies opposite the openings of the blind hole and the mounting hole lies approximately in a plane (E2- E2), which also extends through the axis of the pipe section.

17. A fuel feed according to any of claims 9 to 16, wherein the mounting hole (22) is continued in a sleeve-like extension (26) of the branch (4, 4a).

18. A fuel feed according to any preceding claim, wherein the pipe section and the branch are stainless steel castings.