GB2537642A

GB2537642A - Supply rail body

Info

Publication number: GB2537642A
Application number: GB1506800.0A
Authority: GB
Inventors: Donmez Mehmet; Altinol Cuneyt; Sert Nihat
Original assignee: Delphi International Operations Luxembourg SARL
Current assignee: Delphi International Operations Luxembourg SARL
Priority date: 2015-04-22
Filing date: 2015-04-22
Publication date: 2016-10-26
Also published as: GB201506800D0

Abstract

A supply rail body 2 for a common rail fuel injection system, having a body section 4 defining a high pressure gallery 9, and one or more mounting bracket 8 for mounting the supply rail body 2. The one or more mounting bracket 8 each comprises first and second mounting lugs 20, 21. The first mounting lug 20 has a first mounting aperture (23, Fig. 5) and the second mounting lug 21 has a second mounting aperture (24, Fig. 5). The first and second mounting apertures (23, 24, Fig. 5) are arranged coaxially along a first axis (X1, Fig. 5) for receiving a mechanical fastener (25, Fig. 2) to fasten the supply rail body 2. The inner surfaces of the mounting lugs 20, 21 may be inclined outwardly in opposite directions; the inner and outer surfaces of each lug may be parallel. This arrangement allows for weight saving due to the mass-efficient design of the mounting assembly, in which material is removed from a standard solid bracket.

Description

SUPPLY RAIL BODY

TECHNICAL FIELD

The present disclosure relates to a supply rail body. More particularly, but not exclusively, the present disclosure relates to a supply rail body for a common rail fuel supply system.

BACKGROUND

It is known to use a common rail fuel supply system to supply fuel to one or more fuel injector. The one or more fuel injector is adapted to inject high pressure fuel into a combustion chamber of an internal combustion engine. The fuel can be a diesel fuel which is injected at high pressure into the combustion chamber. A high pressure pump delivers fuel from a reservoir to a high pressure gallery disposed in a supply rail body. The supply rail body 102 can be manufactured from laser welded sections. The sections can be formed as separate components which are formed separately and then welded together.

An end elevation of a known supply rail body 102 is shown in Figure 6. The supply rail body 102 comprises a body section 104 and a series of mounting brackets 108 for mounting the supply rail body 102. The mounting brackets 108 each consist of a single mounting lug having a mounting aperture 123 extending along a first axis X1 to receive a bolt to fasten the supply rail body 102 to an engine block. As shown in Figure 6, the mounting brackets 108 each have a continuous profile. A first end of the mounting brackets 108 forms an engine interface; and a second end cooperates with a head of the bolt. The thickness of the mounting brackets can vary depending on the application. The mounting brackets 108 can be very thick as compared to the remainder of the supply rail body. Once these boundaries are applied to the forged body section 104, the forged body section 104 may have an excessive bar diameter, which can potentially create issues during the forging process. This can also lead to higher production costs.

The supply rail body can be forged integrally with the mounting brackets. Again, the relatively large thickness of the mounting brackets can cause problems during forging of the supply rail body.

It is against this backdrop that the present invention has been conceived. At least in certain embodiments the present invention seeks to provide a supply rail body which overcomes or reduces problems associated with the prior art arrangements.

SUMMARY OF THE INVENTION

Aspects of the present invention relate to a supply rail body for a common rail fuel injection system; and to a common rail fuel injection system.

According to a further aspect of the present invention there is provided a supply rail body for a common rail fuel injection system, the supply rail body comprising: a body section defining a high pressure gallery; and one or more mounting bracket for mounting the supply rail body; wherein the one or more mounting bracket each comprise first and second mounting lugs; the first mounting lug having a first mounting aperture and the second mounting lug having a second mounting aperture, the first and second mounting apertures being arranged coaxially along a first axis for receiving a mechanical fastener to fasten the supply rail body. By forming each mounting bracket from first and second mounting lugs, the mass of the supply rail body can be reduced. The first and second lugs can be in the form of projections for receiving the mechanical fastener.

In certain embodiments, a finished forge mass of the supply rail body can be reduced by up to approximately 10% compared to prior art arrangements. A cross-sectional area of the mounting bracket can be reduced by up to approximately 24% compared to prior art arrangements. The reduction in this cross-sectional area can facilitate fabrication of the supply rail body. For example, if the supply rail body is a forged component, the reduction in the cross-sectional area can facilitate forging.

The first and second mounting lugs can be spaced apart from each other along the first axis.

A concave recess can be formed between the first and second mounting lugs. A hollow region can be formed between the first and second mounting lugs. By forming the mounting bracket from first and second mounting lugs (rather than a single lug having a continuous section), the problems in forging the supply rail body can be overcome or ameliorated. In particular, the thickness of the first and second mounting lugs can more closely correspond to the thickness of the body section. At least in certain embodiments, the mounting bracket can provide a robust installation of the supply rail body using less material and providing appropriate proper draft angles. The interface with the internal combustion engine can remain unaffected when compared to the prior art arrangements. The material required to form the one or more mounting bracket can be reduced without affecting their functionality.

The one or more mounting bracket can each be a one-piece component. The first and second mounting lugs can be formed integrally in a single component. The one or more mounting bracket can, for example, be formed by forging, casting, machining or other fabrication techniques.

The one or more mounting brackets can be made of metal, for example steel or stainless steel.

The supply rail body can be a forged one-piece component. The body section and the one or more mounting bracket can be formed integrally. Alternatively, the supply rail body can be formed by welding a plurality of components together.

The first mounting lug can comprise a first inner surface. The first inner surface can be arranged substantially perpendicular to the first axis. Alternatively, the first inner surface can be inclined at a first angle relative to the first axis. The first angle can be an acute angle. The first angle can be in the range 15° to 45°. In certain embodiments, the first angle can be 30°.

The first angle can define a first draft angle of the first inner surface to facilitate removal of the first mounting lug from a die.

The second mounting lug can comprise a second inner surface. The second inner surface can be arranged substantially perpendicular to the first axis. Alternatively, the second inner surface can be inclined at a second angle relative to the first axis. The second angle can be an acute angle. The second angle can be in the range 15° to 45°. In certain embodiments, the second angle can be 30°. The second angle can define a second draft angle of the first inner surface to facilitate removal of the second mounting lug from a die.

The first and second inner surfaces can be opposing surfaces. The first inner surface and/or the second inner surface can be generally planar.

The first and second inner surfaces can be inclined in opposite directions such that the first and second inner surfaces open outwardly.

The first and second lugs have respective first and second outer surfaces. The first and second outer surfaces can be arranged substantially parallel to each other. The first and second outer surfaces can be arranged perpendicular to the first axis. The first outer surface can be configured operatively to engage a head of the mechanical fastener. The second outer surface can be configured operatively to engage a mounting surface. The mounting surface can, for example, be defined on an outer surface of an engine block or casing.

The first and second mounting apertures can be formed in each of the first and second lugs. The first and second mounting apertures can be in the form of first and second bores extending through the respective first and second mounting lugs.

The first and second mounting lugs can be arranged to form a C-shaped mounting bracket.

The supply rail body can comprise two or more mounting brackets. For example, the supply rail body can comprise three or four mounting brackets.

The high pressure gallery can extend at least partway along a length of the body section.

The high pressure gallery can extend along a central longitudinal axis of the body section. The supply rail body can comprise one or more inlet port; and/or one or more outlet port. The supply rail body can comprise a pressure relief port and/or a high pressure valve port and/or a sensor port.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the present invention will now be described, by way of example only, with reference to the accompanying figures, in which: Figure 1 shows a schematic representation of a common rail fuel injection system incorporating a supply rail body in accordance with an embodiment of the present invention; Figure 2 shows a first perspective view of the supply rail body shown in Figure 1; Figure 3 shows a second perspective view of the supply rail body shown in Figure 1; Figure 4 shows a third perspective view of the supply rail body shown in Figure 1; Figure 5 shows a section through the supply rail body shown in Figure 1; and Figure 6 shows an end view of a supply rail body according to a prior art arrangement.

DETAILED DESCRIPTION

A common rail fuel injection system 1 comprising a supply rail body 2 in accordance with an embodiment of the present invention will now be described with reference to Figures 1 to 5.

The common rail fuel injection system 1 is suitable for an internal combustion engine 3, as shown schematically in Figure 1. The internal combustion engine 3 is a compression ignition engine and the supply rail body 2 is configured to supply high pressure diesel fuel.

As shown in Figure 2, the supply rail body 2 comprises a body section 4, an inlet port 5, a plurality of outlet ports 6, a pressure relief port 7, and a plurality of mounting brackets 8. In the present embodiment the supply rail body 2 is a one-piece component and the mounting brackets 8 are formed integrally with the body section 4. The supply rail body 2 and the mounting brackets 8 are forged from a cylindrical bar. The supply rail body 2 can, for example, be formed from a low carbon micro-alloy steel. The body section 4 is generally tubular and defines a high pressure gallery 9 extending along a central longitudinal axis Y1 of the supply rail body 2. The inlet port 5 and the outlet ports 6 are in fluid communication with the high pressure gallery 9. The inlet port 5 is fluidly connected to a high pressure supply line 10 which is connected to a high pressure fuel pump 11. In use, the fuel pump 11 pumps fuel from a reservoir 12 to the supply rail body 2. In the present embodiment there are six (6) outlet ports 6 connected to respective fuel injectors 13 for controlling the injection of fuel into the combustion chambers of the internal combustion engine 3. A pressure relief valve 14 is connected to the pressure relief port 7. The pressure relief valve 14 opens if the pressure in the high pressure gallery 9 exceeds a predetermined maximum pressure. The pressure relief valve 14 is connected to a return line 15 through which fuel is returned to the fuel reservoir 12 when the pressure exceeds the predetermined maximum pressure. The pressure relief valve 14 can, for example, comprise a spring member which cooperates with a valve member to determine the maximum operating pressure. It will be appreciated that the supply rail body 2 can comprise fewer than or more than six (6) outlet ports 6 depending on the configuration of the internal combustion engine 3. The supply rail body 2 also comprises a pressure limiting valve port 16 for receiving a pressure limiting valve 17. The supply rail body 2 also comprises a high pressure sensor port 18 for receiving a high pressure sensor 19. The high pressure sensor port 18 in the present embodiment extends radially outwardly, but in modified arrangements can be arranged axially. The pressure relief valve 14 could be replaced by a high pressure valve. The supply rail body 2 can comprise more than one inlet port 5.

There are three (3) mounting brackets 8 for mounting the supply rail body 2 to the internal combustion engine 3. The first, second and third mounting brackets 8 are labelled separately as 8-1, 8-2, 8-3 in the accompanying figures for clarity. The first, second and third mounting brackets 8-1, 8-2, 8-3 have the same configuration and only one will now be described for the sake of brevity. The mounting brackets 8 each comprise a first mounting lug 20 and a second mounting lug 21. The first and second mounting lugs 20, 21 are spaced apart from each other along a first axis X1. The first and second mounting lugs 20, 21 in the present embodiment are arranged such that the mounting bracket 8 is generally C-shaped. A concave recess 22 is formed between the first and second mounting lugs 20, 21. The first and second mounting lugs 20, 21 extend outwardly by 20.5mm. The first mounting lug 20 has a thickness (measured along the first axis X1) or 10mm. It will be appreciated that the dimensions of the first and second mounting lugs 20, 21 can be varied for different applications.

The first and second mounting lugs 20, 21 have respective first and second mounting apertures 23, 24. The first and second mounting apertures 23, 24 in the present embodiment are in the form of first and second circular bores disposed coaxially on the first axis Xl. The first and second mounting apertures 23, 24 have a diameter of 12mm in the present embodiment, but this can be increased or decreased for different applications. As shown in Figure 2, a mechanical fastener 25 is inserted through the first and second mounting apertures 23, 24 in each mounting bracket 8 to fasten the supply rail body 2. The mechanical fastener 25 in the present embodiment is in the form of a threaded bolt for cooperating with a threaded aperture (not shown) formed in an engine block of the internal combustion engine 3. The supply rail body 2 is configured such that the first mounting lug 20 cooperates with a head portion of the mechanical fastener 25; and the second mounting lug 21 cooperates with a mounting surface (not shown) formed on the engine block.

As shown in Figure 5, the first mounting lugs 20 each have a first inner surface 26 and a first outer surface 27. The first inner surface 26 and the first outer surface 27 are arranged substantially perpendicular to the first axis Xl. In use, the mechanical fastener 25 engages the first outer surface 27. The second mounting lugs 21 each have a second inner surface 28 and a second outer surface 29. The second inner surface 28 is inclined at a first acute angle al relative to the first axis Xl. In the present embodiment the first acute angle al is 30°. The second outer surface 28 is arranged substantially perpendicular to the first axis Xl.

In use, the second outer surface 29 engages the mounting surface of the engine block. In alternate embodiments, the first inner surface 26 can be inclined at an acute angle relative to the first axis Xl. A sidewall 30 is formed between the first and second mounting lugs 20, 21.

The sidewall 30 is substantially planar and is disposed parallel to the first axis X1. In the present embodiment the sidewall 30 extends the length of the body section 4 and has a width of approximately 17mm. First and second radii are formed at each side of the sidewall 30 to form a progressive interface with the first and second inner surfaces 26, 28.

The first acute angle al is defined in a reference plane extending perpendicular to the central longitudinal axis Y1 of the body section 4. The second inner surface 28 is inclined at said first acute angle al to define a first draft angle. The first and second outer surfaces 27, 29 are substantially planar and are disposed substantially parallel to each other. A machining operation can be performed to perform the first and second outer surfaces 27, 29.

The parallel arrangement of the first and second outer surfaces 27, 29 helps ensure that loads are transmitted axially along the mechanical fastener 25. In the present embodiment the first and second outer surfaces 27, 29 are spaced apart by 52mm along said first axis X1. The configuration of the first and second outer surfaces 27, 29 is unaffected by the orientation of the first and second inner surfaces 26, 28.

As outlined above, the supply rail body 2 in the present embodiment is formed by a forging process. The mounting brackets 8 are formed during the forging process. In particular, the concave recess 22 is formed by the forge die during forging of the supply rail body 2. The profile of the concave recess 22 is adapted to ensure that the first and second mounting lugs 20, 21 provide a robust installation for the supply rail body 2. The profile of the concave recess 22 and/or the thickness of the mounting brackets 8 can be varied for different applications.

The supply rail body 2 has been described as a one-piece forged component. It will be appreciated that in a variant the supply rail body 2 can be assembled from separate components. In particular, the mounting brackets 8 can be welded to the body section 4. In this variant, the mounting brackets 8 can each be formed as a one-piece component. The mounting brackets 8 could, for example, be forged, cast, machined or fabricated using other techniques.

It will be appreciated that various changes and modifications can be made to the supply rail body 2 described herein without departing from the scope of the present application. For example, it will be appreciated that the first acute angle al can be adjusted. Alternatively, or in addition, the second inner surface 28 can be inclined at a second acute angle relative to the first axis Xl. Equally, spacing between the first and second mounting lugs 20, 21 can be altered for different applications.

Claims

CLAIMS: 1. A supply rail body (2) for a common rail fuel injection system (1), the supply rail body (2) comprising: a body section (4) defining a high pressure gallery (9); and one or more mounting bracket (8) for mounting the supply rail body (2); wherein the one or more mounting bracket (8) each comprise first and second mounting lugs (20, 21); the first mounting lug (20) having a first mounting aperture (23) and the second mounting lug (21) having a second mounting aperture (24), the first and second mounting apertures (23, 24) being arranged coaxially along a first axis (X1) for receiving a mechanical fastener (25) to fasten the supply rail body (2).
2. A supply rail body (2) as claimed in claim 1, wherein the one or more mounting bracket (8) is a forged one-piece component.
3. A supply rail body (2) as claimed in claim 1, wherein the supply rail body (2) is a forged one-piece component.
4. A supply rail body (2) as claimed in any one of claims 1, 2 or 3, wherein the first mounting lug (20) comprises a first inner surface (26), the first inner surface (26) being inclined at a first angle relative to the first axis (X1).
5. A supply rail body (2) as claimed in any one of the preceding claims, wherein the second mounting lug (21) comprises a second inner surface (28), the second inner surface (28) being inclined at a second angle relative to the first axis (X1).
6. A supply rail body (2) as claimed in claims 4 and 5, wherein the first and second inner surfaces (26, 28) are inclined in opposite directions such that the first and second inner surfaces (26, 28) open outwardly.
7. A supply rail body (2) as claimed in any one of the preceding claims, wherein the first and second mounting lugs (20, 21) have respective first and second outer surfaces (27, 29), the first and second outer surfaces (27, 29) being arranged substantially parallel to each 35 other.
8. A supply rail body (2) as claimed in any one of the preceding claims, wherein the first and second mounting apertures (23, 24) formed in each of the first and second mounting lugs (20, 21) are in the form of first and second bores extending through the respective first and second mounting lugs (20, 21).
9. A supply rail body (2) as claimed in any one of the preceding claims, wherein the first and second mounting lugs (20, 21) are arranged to form a C-shaped mounting bracket (8).