A fuel rail having a sheet metal support and a production method thereof

Abstract

The present invention proposes a fuel rail (10) comprises at least one sheet metal support (20) to support and fix the mounting bracket (30) onto the tubular body (11) of the fuel rail (10) wherein the sheet metal support (20) is arranged between the mounting bracket (30) and an outer wall (12) of the tubular body (11). Also, present invention proposes a production method of the fuel rail (10) having production steps of: the sheet metal support (20) is brazed on the tubular body (11) of the fuel rail (10) such as forming a first brazing area (41) on the fuel rail (10), the mounting bracket (30) is brazed on the sheet metal support (20) such as forming a second brazing area (42) on the sheet metal support (20) and, the fuel rail (10) is exposed to heat.

Description

[0001] SPECIFICATION

[0002] A FUEL RAIL HAVING A SHEET METAL SUPPORT AND A PRODUCTION METHOD THEREOF

[0003] Technical Field of the Invention

[0004] The present invention relates to fuel rail having a sheet metal support for a mounting bracket for fuel rails providing connection of the fuel rail to the engine. In particular, the present invention relates to a fuel rail according to the preamble of the appended independent claim.

[0005] Background of the Invention

[0006] In internal combustion engines, fuel transfer to fuel injectors is provided by means of a fuel rail provided in the form of a pipe. A high pressurized fuel is provided through the fuel rail during operation of the fuel injectors. The fuel rail is mounted and fixed on an internal combustion engine via mounting brackets.

[0007] In general, the mounting bracket must be mounted on a part of an engine body in order to absorb operational loads and to fix the fuel rail onto the engine block. The fuel rail is formed via brazing to form a tubular body and the material is a stainless- steel alloy.

[0008] In the prior art, an US11434860B2 document is published. According to the disclosure, a mounting support is formed by two metal brackets, each configured as a sheet-metal formed part. Each metal bracket has a holding portion adapted to the outer contour of the base body, a leg angled relative to the holding portion, and a mounting flange at the free end of the leg and angled away therefrom. A length portion of the base body is received between the holding portions. The holding portions partially surround the base body.

[0009] Another prior art document is published with the priority number TR201613691. The present invention relates to a connection plate providing connection of a holder to a fuel rail transferring fuel to injectors in internal combustion gasoline engines and comprising an assembly region for connecting the connection plate to the holder, a brazing region for brazing the connection plate to the fuel rail, and an intermediate region extending between the assembly region and the brazing region.

[0010] The connection plates which are attached to the fuel rail by brazing which expose to high stress when the engine in use. During operation of the engine, the motor heats up and a thermal expansion causes a high stress. Said high stress especially affects the mounting bracket through brazed sharp corners.

[0011] The brazing connection between any connection embodiment and the fuel rail or (directly the mounting bracket can be brazed onto the fuel rail body) mounting bracket and the fuel rail may break before the final fixation, which consequently results in scrapped pieces. In addition, high stressed portions of the mounting bracket may weaken the connection to the fuel rail.

[0012] Brief Description of the Invention

[0013] Primary object of the present invention is to overcome the abovementioned shortcomings of the prior art. Depending on this phenomenon, the main object of the present invention is to reduce the number of the type of the mounting brackets by using one type reliable mounting bracket in a strength and reliable manner.

[0014] Another object of the present invention is to provide a mounting bracket where the stress, occurring in brazed section, is reduced.

[0015] Another object of the present invention is to provide a mounting bracket in which sharped brazing corners resulting in high stress values are eliminated.

[0016] Another object of the present invention is to provide a mounting bracket having less material (i.e. without a support bracket) which in results cost reduction.

[0017] Another object of the present invention is to provide a mounting bracket in which stress values on critical areas, because of a braze area due to smooth transition on corners, is reduced.

[0018] The present invention proposes a fuel rail transferring pressurized fuel to fuel injectors in an internal combustion engine, having a tubular body and at least one mounting bracket to fix the fuel rail on an engine block. According to the present invention, the fuel rail comprises at least one sheet metal support to support and fix the mounting bracket onto the tubular body of the fuel rail wherein the sheet metal support is arranged between the mounting bracket and an outer wall of the tubular body. Thus, stress on brazing between mounting bracket and tubular body of the fuel rail, is reduced. Also, a widen brazing area with the sheet metal support is provided on the tubular body.

[0019] In a possible embodiment of the subject matter invention, the sheet metal support has rounded edges. Thus, sharped brazing corners resulting in high stress values are eliminated and smooth transition on corners is provided.

[0020] In a possible embodiment of the subject matter invention, the fuel rail has a number of mounting brackets and a number of sheet metal support corresponding to the mounting brackets. Thus, the fuel rail has enough numbered mounting bracket to mount the fuel rail onto the engine block.

[0021] In a possible embodiment of the subject matter invention, the sheet metal support has a radius shaped body portion such that the radius shaped body portion corresponds to an outer shape of the outer wall of the tubular body. Thus, a reliable holder solder and a holder brazing interfaces are provided on the tubular body. This impacts lifetime and strength of the brazing regions. In addition to that, lifetime and strength of the brazing region on the tubular body are enhanced.

[0022] In a possible embodiment of the subject matter invention, the sheet metal support has a wall thickness less than a wall thickness of the mounting bracket.

[0023] In a possible embodiment of the subject matter invention, the sheet metal support has a less weight than a total weight of the mounting bracket.

[0024] Although it weighs less, the sheet metal support has the capacity to carry the mounting bracket by overcoming the stresses on the sheet metal support. Therefore, the sheet metal support carries the mounting bracket, which has much more weight and a wider wall thickness than its own weight and wall thickness.

[0025] The present invention proposes also proposes a production method of the fuel rail having production steps of: - the sheet metal support is brazed on the tubular body of the fuel rail such as forming a first brazing area on the fuel rail and,

[0026] - the mounting bracket is brazed on the sheet metal support such as forming a second brazing area on the sheet metal support and,

[0027] - the fuel rail is exposed to heat.

[0028] Thus, stresses on the brazing areas between the mounting bracket and the tubular body of the fuel rail and also between the mounting bracket and the sheet metal support, are reduced. In addition to that, a widened first brazing area according to a prior art brazing region on the tubular body is provided so as to decrease the stresses on the fuel rail.

[0029] In a possible method of the subject matter invention, the sheet metal support is shaped as having a radius shaped body portion such that the radius shaped body portion will be corresponding to a radius shaped outer wall of the tubular body. Thus, a reliable holder solder and a holder brazing interfaces are provided on the tubular body. This impacts lifetime and strength of the brazing regions. In addition to that, lifetime and strength of the brazing region on the tubular body are enhanced.

[0030] In a possible method of the subject matter invention, the sheet metal support is shaped as having rounded edges. Thus, formation of sharp edges in braze accumulated in the first brazing area is prevented, and thus, the stress accumulation on braze is reduced.

[0031] In a possible method of the subject matter invention, the sheet metal support is formed as having a wall thickness less than a wall thickness of the mounting bracket. Although, the sheet metal support has a less wall thickness, the sheet metal support provides reliable brazing interface having less stress values when comparing with the prior art brazing region.

[0032] In a possible method of the subject matter invention, the sheet metal support is fixed on the outer wall of the fuel rail via spot welding before brazing process. Thus, a reliable fixation is provided for preparation to brazing process. In a possible method of the subject matter invention, the mounting bracket is fixed on the sheet metal support via spot welding before brazing process. Thus, a reliable fixation is provided for preparation to brazing process.

[0033] In a possible method of the subject matter invention, a copper material as a solder filling material is used to braze the metals for brazing process. Thus, a reliable solder filling material is provided for brazing.

[0034] In a possible method of the subject matter invention, a brazing interface on the sheet metal support is provided as 190 mm2. Thus, a safe and durable brazing interface on the sheet metal support is provided without the wall thickness of the sheet metal support expanding too much.

[0035] Brief Description of the Figures

[0036] The figures, whose brief explanations are herewith provided, are solely intended for providing a better understanding of the present invention and are as such not intended to define the scope of protection or the context in which said scope is to be interpreted in the absence of the description.

[0037] Figure 1 shows a perspective view of a part of a fuel rail having a mounting bracket and a sheet metal support fixed to each other and onto the fuel rail, according to the present invention.

[0038] Figure 2 shows a perspective view of a part of a fuel rail having a mounting bracket and a sheet metal support where just the sheet metal support is fixed to the fuel rail and the mounting bracket is not yet fixed, according to the present invention.

[0039] Figure 3A shows a front perspective view of a sheet metal support, according to the present invention.

[0040] Figure 3B shows a rear perspective view of a sheet metal support, according to the present invention.

[0041] Figure 4 shows a perspective view of another end of a fuel rail having a mounting bracket and a sheet metal support fixed to each other and onto the fuel rail, according to the present invention.

[0042] Figure 5 shows a perspective view of another end of a fuel rail having a mounting bracket and a sheet metal support not yet fixed onto the fuel rail, according to the present invention.

[0043] Figure 6 shows a perspective view of a part of the fuel rail and a sheet metal support which will be brazed onto the fuel rail, according to the present invention.

[0044] Figure 7 shows a perspective view of a part of the fuel rail with a sheet metal support which is brazed onto the fuel rail, according to the present invention in a brazing process.

[0045] Figure 8 shows a prior art brazing process where the mounting bracket is directly brazed onto the fuel rail, in the prior art.

[0046] Figure 9 shows a brazed mounting bracket and brazing areas, according to the present invention in a brazing process.

[0047] Figure 10 shows a side view of a prior art directly brazed mounting bracket onto the fuel rail, in the prior art.

[0048] Figure 11 shows a side view of an indirectly mounted mounting bracket onto the fuel rail, according to the present invention.

[0049] Figure 12 shows a perspective view of a prior art directly brazed mounting bracket onto the fuel rail, in the prior art.

[0050] Figure 13 shows a perspective view of a prior art mounting bracket and the fuel rail not yet mounted to each other, in the prior art.

[0051] Figure 14 shows a perspective view of a prior art mounting bracket onto mounted the fuel rail, in the prior art.

[0052] Figure 15 shows a perspective view of another kind of a prior art mounting bracket in the prior art. Figure 16 shows a perspective view of a prior art mounting bracket onto mounted the fuel rail, in the prior art.

[0053] Figure 17 shows a perspective front view of a prior art fuel rail.

[0054] Figure 18 shows a two-dimensional bottom side view of a prior art fuel rail.

[0055] Figure 19 shows a representative view of stress accumulations occurring on brazed section of the mounting bracket according to the prior art.

[0056] Figure 20 shows a representative view of stress accumulations occurring on brazed section of the mounting bracket and of the sheet metal support according to the present invention.

[0057] Detailed Description of the Invention

[0058] The present invention proposes a fuel rail (10) having at least one sheet metal support (20) for at least one mounting bracket (30) and a production method of the fuel rail (10) having the mounting bracket (30).

[0059] The fuel rail (10) according to the present invention is a common rail having a tubular body (11) and having a number of mounting bracket (30) and a number of sheet metal support (20) to braze and fix the mounting brackets (30) onto the fuel rail (10). Alternative embodiments of the fuel rail (10) can be seen from the figures 17 and 18.

[0060] The tubular body (11) of the fuel rail (10) is at an elongated cylindrical tube form and has a radius outer wall (12). The tubular body (11) is like a line having pressurized fuel feed through inside from one end of the fuel rail (10). A number of injector cup (60) is also uniformed with the tubular body (11) or fixed or brazed onto the tubular body (11) and near to the mounting brackets (30) of the fuel rail (10). A number of fuel injector (not shown in the figures) is mounted to a number of injector cup (60). Therefore, the pressurized fuel is feed towards fuel injectors. The fuel rail (10) must be reliably fixed onto the engine block (not shown in the figures). The mounting brackets (30) are brought into an integrated embodiment with the tubular body (11 ) of the fuel rail (10) via a brazing method of the mounting bracket (30) onto the tubular body (11 ) according to the prior art embodiment (see Figures 8, 10, 12, 16 and 17). The fuel rail (10) is fixed onto the engine block via passing a pin (not shown in the figures) through a hole (33) of the mounting bracket

[0061] (30).

[0062] The mounting brackets (30) have some types having different shapes. In the given figures 13, 14 ,15 and 16; different types of mounting brackets (30) are seen. One of the types of the mounting brackets (30) mostly and essentially has a cylindrical body

[0063] (31 ). As can be seen from the figures 15 and 16; the mounting bracket (30) can have additional mounting and fixing embodiments on itself, in the prior art embodiments. Also, in the figure-14, the mounting bracket (30) can have a support bracket (50) on an upper side of the mounting bracket (30), according to the prior art.

[0064] Figure 12 shows a perspective view of a prior art directly brazed mounting bracket (30) onto the fuel rail (10) such as forming a prior art brazing region (40), in the prior art. Figure 13 shows a perspective view of a prior art mounting bracket (30) and the fuel rail (10) which are not yet mounted to each other, in the prior art. This kind of mounting bracket (30) is also used for the present invention and can be seen form the figure 1 and 2. Therefore, a reliable mounting bracket (30) is selected from the prior art mounting brackets (30). Figure 8 shows a prior art brazed process where the mounting bracket (30) is directly brazed onto the fuel rail (10), in the prior art.

[0065] While the mounting bracket (30) is selected, also a distance of the mounting bracket (30) to the fuel rail (10) should be considered. The distance of the mounting bracket (30) should not be so far from the tubular body (11) such as bringing mounting problems on the engine block and packaging problems for the fuel rail (10). Therefore, a first distance (a) is defined for a distance from a center of the mounting bracket (30) to a center of the injector cup (60) on a Y- vertical axis according to the figure-18. Prior art mounting brackets (30) can be seen from the figures: 15 and 16. For instance, the prior art mounting brackets (30) such as in the figures 15 and 16 bring additional mounting distance at an X-horizontal axis (axis can change according to the position of the figures). Also, a second distance (b) can be considered during forming the mounting bracket (30) and during finding a method to mount and fix the mounting bracket (30) to the fuel rail (10). The second distance (b) is defined as a distance at a Z-diagonal axis and shown in the figure-18 and the second distance (b) is defined from a center of the mounting bracket (30) to a center of the injector cup (60).

[0066] A main object of the present invention is to reduce the number of the type of the mounting brackets (30) by using one type reliable mounting bracket (30) in a strength and reliable manner.

[0067] The sheet metal support (20) is a planar metal form which is proceeded to bending process. Therefore, the sheet metal support (20) has a radius body portion (21) which is bended at a corresponding angle to a radius outer wall (32) of the fuel rail (10). Four of the corners of the rectangular sheet metal are rounded by machining or cutting and thus, the sheet metal support (20) has rounded edges (22).

[0068] Also, the mounting bracket (30) has a cylindrical body (31) and has radius outer wall (32). When the mounting bracket (30) is directly brazed onto the fuel rail (10), a maximum stress on the prior art brazing region (40) on the fuel rail (10) is seen as 521 Mpa. This stress is calculated under only pressure load.

[0069] In another test, when the mounting bracket (30) is directly brazed onto the fuel rail

[0070] (10), a maximum stress on the prior art brazing region (40) on the fuel rail (10) is seen as 428 Mpa. This stress is calculated under temperature load. The prior art brazing region (40) which is under a maximum stress is shown in the figure-19. In the prior art, the mounting bracket (30) is directly brazed on the tubular body (11 ) of the fuel rail (10).

[0071] In a detail description of the present invention, the mounting bracket (30) is directly brazed on a sheet metal support (20) which has a weight less than a weight of the mounting bracket (30).

[0072] In a production method of the fuel rail (10), the sheet metal support (20) is directly brazed on the tubular body (11) of the fuel rail (10) such as forming a first brazing area (41 ) on the fuel rail (10). The junction of the radius body portion (21 ) of the sheet metal support (20) corresponds to the radius outer wall (12) of the tubular body

[0073] (11 ). The sheet metal support (20) has a wall thickness less than a wall thickness of the mounting bracket (30) and the sheet metal support (20) has a less weight than a total weight of the mounting bracket (30). This impacts lifetime and strength of the brazing regions. After that, the mounting bracket (30) is brazed on the sheet metal support (20) such as forming a second brazing area (42) on the sheet metal support (20).

[0074] In the first step of the brazing processes, the sheet metal support (20) is fixed on the outer wall (12) of the fuel rail (10) via spot welding. After that, the mounting bracket (30) is fixed on the sheet metal support (20) via spot welding. After the fixation processes, the main brazing process are realized. A solder filling material is used to braze the metals. This material is a copper material. The first brazing area (41 ) and the second brazing area (42) are filled with the solder filling. After that the fuel rail (10) is exposed to heat. Then a reliable fixation of the mounting brackets (30) and the sheet metal supports (20) for the integration to the fuel rail (10) is realized.

[0075] Figure 19 shows a representative view of stress accumulations occurring on brazed section of the mounting bracket (30), according to the prior art. Figure 20 shows a representative view of stress accumulations occurring on brazed section of the mounting bracket (30) and of the sheet metal support (20) according to the present invention.

[0076] A maximum stress on the prior art brazing region (40) of the fuel rail (10) is seen as 521 Mpa in the prior art of the fuel rail (10). With the present invention and the method according to this invention, the maximum stress on the tubular body (11 ) is decreased from 521 Mpa to Mpa 271 Mpa under pressure loads. Therefore, the stress, occurring in brazed section on the tubular body (11), is reduced.

[0077] A maximum stress on the prior art brazing region (40) of the fuel rail (10) is seen as 428 Mpa in the prior art of the fuel rail (10). With the present invention and the method according to this invention, the maximum stress on the tubular body (11 ) is decreased from 428 Mpa to Mpa 347 Mpa under temperature loads. Therefore, the stress, occurring in brazed section on the tubular body (11), is reduced.

[0078] In addition, a brazing interface on the prior art brazing region (40) was 96 mm2. With the invention, a brazing interface on the sheet metal support (20) is increased to 190 mm2. Thus, this area has not expanded much as negatively impacting the first distance (a) and the second distance (b) but also, the brazing interface on the sheet metal support (20) provides a strength embodiment.

[0079] Therefore, the present invention provides a mounting bracket (30) in which sharped brazing corners resulting in high stress values are eliminated.

[0080] The present invention provides a mounting bracket (30) having less material (i.e. without a support bracket (50) especially on the mounting bracket (30) (see. Figure- 11) or without additional embodiments (34) on the mounting bracket (30)) which in results cost reduction. Advantageously, the present invention provides a mounting bracket (30) in which stress values on critical areas, because of a braze area due to smooth transition on corners, is reduced.

[0081] Reference numbers:

[0082] 10. Fuel rail

[0083] 11. Tubular body

[0084] 12. Outer wall

[0085] 20. Sheet metal support

[0086] 21. Body portion

[0087] 22. Rounded edge

[0088] 30. Mounting bracket

[0089] 31. Cylindrical body

[0090] 32. Radius outer wall

[0091] 33. Hole

[0092] 34. Additional embodiment

[0093] 40. Prior art brazing region

[0094] 41. First brazing area

[0095] 42. Second brazing area

[0096] 50. Support bracket

[0097] 60. Injector cup a. first distance b. second distance

Claims

CLAIMS:

1. A fuel rail (10) transferring pressurized fuel to fuel injectors in an internal combustion engine, having a tubular body (11) and at least one mounting bracket (30) to fix the fuel rail (10) on an engine block characterized in that, the fuel rail (10) comprises at least one sheet metal support (20) to support and fix the mounting bracket (30) onto the tubular body (11 ) of the fuel rail (10) wherein the sheet metal support (20) is arranged between the mounting bracket (30) and an outer wall (12) of the tubular body (11).

2. The fuel rail (10) according to claim 1 , wherein the sheet metal support (20) has rounded edges (22).

3. The fuel rail (10) according to claim 1 or 2, wherein the fuel rail (10) has a number of mounting brackets (30) and a number of sheet metal support (20) corresponding to the mounting brackets (30).

4. The fuel rail (10) according to anyone of the preceding claims, wherein the sheet metal support (20) has a radius shaped body portion (21) such that the radius shaped body portion (21) corresponds to an outer shape of the outer wall (12) of the tubular body (11).

5. The fuel rail (10) according to anyone of the preceding claims, wherein the sheet metal support (20) has a wall thickness less than a wall thickness of the mounting bracket (30).

6. The fuel rail (10) according to anyone of the preceding claims, wherein the sheet metal support (20) has a less weight than a total weight of the mounting bracket (30).

7. A production method of the fuel rail (10) characterized in that having production steps of:- the sheet metal support (20) is brazed on the tubular body (11) of the fuel rail (10) such as forming a first brazing area (41 ) on the fuel rail (10),- the mounting bracket (30) is brazed on the sheet metal support (20) such as forming a second brazing area (42) on the sheet metal support (20) and,- the fuel rail (10) is exposed to heat.

8. The production method of the fuel rail (10) according to claim 7, wherein the sheet metal support (20) is shaped as having a radius shaped body portion (21 ) such that the radius shaped body portion (21) will be corresponding to a radius shaped outer wall (12) of the tubular body (11 ).

9. The production method of the fuel rail (10) according to claim 7 or 8, wherein the sheet metal support (20) is shaped as having rounded edges (22).

10. The production method of the fuel rail (10) according to anyone of the claims 7 - 9, wherein the sheet metal support (20) is formed as having a wall thickness less than a wall thickness of the mounting bracket (30).

11. The production method of the fuel rail (10) according to anyone of the claims 7 - 10, wherein the sheet metal support (20) is fixed on the outer wall (12) of the fuel rail (10) via spot welding before brazing process.

12. The production method of the fuel rail (10) according to claim 11 , wherein the mounting bracket (30) is fixed on the sheet metal support (20) via spot welding before brazing process.

13. The production method of the fuel rail (10) according to anyone of the claims 7- 12, wherein a copper material as a solder filling material is used to braze the metals for brazing process.

14. The production method of the fuel rail (10) according to anyone of the claims 7- 13, wherein a brazing interface on the sheet metal support (20) is provided as 190

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