Fuel injector assembly

Abstract

 A fuel rail and injector assembly comprises a fuel delivery rail (14), a fuel injector (12) having an inner fuel delivery channel (22) and a mounting end (10), and mounting means (16) for mounting said fuel injector (12) to said fuel delivery rail (14), said mounting means being arranged on said fuel delivery rail. According to the invention, the said mounting means comprise a fitting (20) which is insertable into said fuel delivery channel (22) of said fuel injector, and clip means (28, 30) extending along an outer surface of said mounting end of said fuel injector when said fuel injector is mounted on said fuel delivery rail, said clip means for co-operating with retaining means (32) on said outer surface of said mounting end of said injector.

Description

Introduction

[0001] The present invention relates to a fuel rail and injector assembly for an internal combustion engine and more particularly to a connecting arrangement for snap fastening a fuel injector to a fuel rail.

[0002] It is known in the art relating to fuel rail and injector assemblies to mount a mounting end of a fuel injector in a fuel rail injector cup utilizing an assembly including an injector clip or other intermediary connecting member to effect the connection. A fuel rail assembly of this kind is disclosed e.g. in US patent 5,803,052. The well-known injection clip complicates the connection and increases the cost of the assembly.

[0003] In order to overcome this disadvantage US patent 5,724,946 proposes a fuel rail and injector assembly that snap fastens together and thus eliminates the necessity for an injector clip or other intermediary fastening member. The snap fastening means comprise a circumferential projection on an inner surface of the fuel rail cup and an associated circumferential groove on an outer surface of the mounting end of the injector. The circumferential projection on the fuel rail cup is located in the proximity of the open end of the cup. Accordingly, the circumferential groove is located on the injector at a certain distance from the mounting end, such that after insertion of the injector into the fuel rail cup, the circumferential projection of the cup will engage into the circumferential groove of the injector. An o-ring assembly is further arranged on the mounting end of the injector, which after insertion of the injector into the fuel rail cup, bears against the inner surface of the fuel rail cup.

[0004] A major problem with this type of snap fastening means is the rather complex design of both the injector mounting end and the fuel rail cup. In fact, in order to achieve a sealing function of the injector in the fuel rail cup, the o-ring must be mounted in such a way that it does not impair insertion of the mounting end past the retaining means of the cup but nevertheless abuts, after insertion, against the inner wall of the cup. This leads to a rather complex design of the injector mounting end. On the other hand, the circumferential projection of the fuel rail cup complicates the molding of the cup. In fact, the inner diameter of the cup immediately behind the projection is larger than on the projection. The molding of such an undercut in a cylindrical cup requires a rather complex multi-part mold. It is clear that the need for such complex molding equipment considerably increases the production costs for the fuel rail assembly.

Object of the invention

[0005] The object of the present invention is to provide an enhanced fuel rail and injector assembly with snap fit means.

General description of the invention

[0006] In order to overcome the above-mentioned problems, the present invention proposes a fuel rail and injector assembly having mounting means in which the sealing and the retaining function are performed by separate parts of the mounting means. Such a fuel rail and injector assembly comprises a fuel delivery rail, a fuel injector having an inner fuel delivery channel and a mounting end, and mounting means for mounting said fuel injector to said fuel delivery rail, said mounting means being arranged on said fuel delivery rail. According to the invention, the said mounting means comprise a fitting which is insertable into said fuel delivery channel of said fuel injector, and clip means extending along an outer surface of said mounting end of said fuel injector when said fuel injector is mounted on said fuel delivery rail, said clip means for co-operating with retaining means on said outer surface of said mounting end of said injector. With the mounting means used in the present invention, the fitting which is insertable into the inner channel of the injector provides for the leak-tight connection of the injector to the fuel delivery rail. Accordingly, the sealing function of the mounting means is achieved inside the inner channel of the injector. By contrast, the clip means, which retain the injector on the fitting, act on the outer surface of the injector.

[0007] It follows that the design of the clip means and the outer surface of the injector mounting end is much simpler than with the prior art assemblies. First of all, since the clip means does not perform any sealing function, it does not need to surround the mounting end of the injector on its entire periphery. A complex multi-part mould is thus not required for forming the clip means. Furthermore, no o-ring has to be mounted on the injector mounting end so as to not impair insertion of the mounting end past the clip means, which simplifies the design of the mounting end.

[0008] In a preferred embodiment of the invention, the fitting comprises sealing means associated to an inner surface of said fuel delivery channel of said injector. The sealing means can e.g. comprise at least one o-ring seal mounted in at least one necking portion having a reduced outer diameter of said fitting. It will be appreciated, that the o-ring mounted on the fitting will be inserted into the fuel delivery channel of the injector and accordingly does not need to be inserted past the clip means of the mounting means. It follows that the risk of damaging the o-ring on sharp edges of the clip means is prevented.

[0009] In a very simple embodiment, said retaining means on said outer surface of said injector mounting end comprise at least one notch and said clip means comprises at least one tab having hook means, said hook means for engaging into said notch of said outer surface of said mounting end of said injector. During insertion of the fitting into the inner channel of the injector, the hook means of the tab slides along the outer surface of the injector mounting end until it engages into the notch of the mounting end. It should be noted, that in a preferred version of this embodiment, two radially opposed notches are arranged on said mounting end of said injector and two tabs with hook means are provided.

[0010] In a further embodiment, said notch comprises a circumferential groove or at least two partial circumferential grooves and said clip means comprises at least two tabs having hook means, said tabs being distributed around the circumference of said mounting end of said injector. In this case, the hook means of the tabs can engage the notch independent of the orientation of the injector.

[0011] If a specific orientation of the injector is required said mounting means may further comprise at least one index lug for co-operating with an index notch of said mounting end of said injector. It follows that the orientation of the injector will be given once the index lug is locked in the index notch and the injector is secured against rotation about its longitudinal axis.

[0012] It will be appreciated that the mounting means can be advantageously formed of a sheet metal. In fact the fitting of the mounting means can be deep drawn from a sheet metal plate which is cut so as to comprise two radially opposed tabs. These tabs will then be folded by 90° so as to extend substantially in the same direction as the fitting. A rectangular section of each tab may be cut-out at three of its sides and slightly bend inwardly for forming the hook means.

[0013] If the fuel delivery rail is made of metal, the mounting means is preferably brazed onto said fuel delivery rail. If however the fuel delivery rail is a molded plastic part, the mounting means can advantageously be molded onto said fuel delivery rail.

[0014] The present invention further relates to a mounting means for a fuel rail and injector assembly, said fuel rail and injector assembly comprising a fuel delivery rail, and a fuel injector having an inner fuel delivery channel and a mounting end. The mounting means comprises a base plate for mounting said mounting means onto a fuel delivery rail, a fitting extending from said base plate and being insertable into said fuel delivery channel of said injector, and clip means extending from said base plate at a distance from said fitting such that said clip means extend along an outer surface of said mounting end of said injector when said injector is mounted to said fuel rail, said clip means co-operating with retaining means on said outer surface of said mounting end.

[0015] The fitting comprises preferably said sealing means associated to an inner surface of said fuel delivery channel of said injector. These sealing means can comprise at least one o-ring seal mounted on a necking portion of said fitting.

Detailed description with respect to the figures

[0016] The present invention will be more apparent from the following description of a not limiting embodiment with reference to the attached drawings, wherein

Fig.1:

shows a side view of a fuel rail and injector assembly, the injector mounting end being partially cut;

Fig.2:

a section of a blank for forming the mounting means,

Fig.3:

a top view of the blank of fig. 2;

Fig.4:

a side view of the finished mounting means;

Fig.5:

a top view of a specific embodiment of the injector with index notch.

[0017] A preferred embodiment of the fuel rail and injector assembly is shown in fig. 1. It shows a mounting end 10 of an injector 12, which is mounted to a fuel delivery rail 14 by means of mounting means 16.

[0018] The mounting means comprises a base plate 18, which is fixed to the fuel delivery rail 14. In case of a metal fuel rail, the base plate may e.g. be brazed onto the rail. A fitting 20 extends from the base plate 18 towards the injector 12. The fitting 20 is dimensioned so as to be insertable into a fuel delivery channel 22 of the injector 12. An O-ring 24 is mounted on the fitting for cooperating with the inner surface of the fuel delivery channel 22 of the injector. The o-ring 24 is preferably mounted on the fitting 20 in a necking portion 26 (see fig. 2) of the fitting, i.e. in a region of reduced diameter. The o-ring is received in the necking 26 and thus is secured against displacement during insertion of the fitting.

[0019] The mounting means further comprises two tabs 28, which are bend substantially by 90° from the base plate. The tabs 28 are radially opposed with respect to the fitting and extend closely along the outer surface of the injector mounting end 10. Each of the tabs 28 comprises a hook 30 extending inwardly towards the injector mounting end 10. The injector mounting end 10 comprises at its outer periphery a preferably circumferential notch 32. This notch is arranged on the mounting end 10 in such a way that the hooks 30 of the tabs 28 engage in the notch 32, when said injector mounting end is in its mounting position. The hooks 30 and the notch 32 form a snap-fastening which simplifies the mounting of the injector to the rail. After engaging into the notch 32, the hooks 30 retain the injector securely in place.

[0020] The mounting means is preferably an integral part formed of sheet metal. Figs 3 to 4 illustrate the manufacture of such a metal mounting means. After cutting out the base plate 18 with the attached tabs 28, the fitting 20 having a necking portion 26 is formed in on the base plate 18 in a deep-draw process. A rectangular section 30 of each tab is cut out on its three sides adjacent to the fitting 20. These rectangular sections are then slightly bend towards the fitting. Finally, the tabs are bend by 90° so as to extend substantially in the same direction than the fitting. The inwardly bend rectangular sections thus extend towards the fitting and form the hooks of the tabs. In a last step, an o-ring is mounted onto the fitting 12 and seated into the necking portion 26 of the fitting.

[0021] The embodiment of the mounting means shown in fig. 2 to 4 further comprises an index lug 34, which is bend at substantially 90° from the base plate. This index lug is provided for engaging into an axial notch 36 arranged in the outer surface of the injector mounting end. During the mounting of the injector to the rail, the index lug 34 is inserted into the notch 36 and thus secures the injector against rotation around its longitudinal axis.

Claims

1. Fuel rail and injector assembly comprising a fuel delivery rail, a fuel injector having an inner fuel delivery channel and a mounting end, and mounting means for mounting said fuel injector to said fuel delivery rail, said mounting means being arranged on said fuel delivery rail, characterised in that said mounting means comprise
a fitting which is insertable into said fuel delivery channel of said fuel injector, and
clip means extending along an outer surface of said mounting end of said fuel injector when said fuel injector is mounted on said fuel delivery rail, said clip means for co-operating with retaining means on said outer surface of said mounting end of said injector.

2. Fuel rail and injector assembly according to claim 1, wherein said fitting comprises sealing means associated to an inner surface of said fuel delivery channel of said injector.

3. Fuel rail and injector assembly according to claim 2, wherein said fitting comprises at least one necking portion having a reduced outer diameter and wherein said sealing means comprise at least one o-ring seal mounted on said fitting in said necking portion.

4. Fuel rail and injector assembly according to any one of the preceding claims, wherein said retaining means on said outer surface of said mounting end of said injector comprise at least one notch and wherein said clip means comprises at least one tab having hook means, said hook means for engaging into said notch of said outer surface of said mounting end of said injector.

5. Fuel rail and injector assembly according to claim 4, wherein said notch comprises a circumferential groove or at least two partial circumferential grooves and wherein said clip means comprises at least two tabs having hook means, said tabs being distributed around the circumference of said mounting end of said injector.

6. Fuel rail and injector assembly according any one of the preceding claims, wherein said mounting means further comprises at least one index lug for co-operating with an index notch of said mounting end of said injector.

7. Fuel rail and injector assembly according to any one of the preceding claims, wherein said mounting means is made of metal.

8. Fuel rail and injector assembly according to claim 7, wherein said fuel delivery rail is made of metal and wherein said mounting means is brazed onto said fuel delivery rail.

9. Fuel rail and injector assembly according to claim 7, wherein said fuel delivery rail is a molded plastic part and wherein said mounting means is molded onto said fuel delivery rail.

10. Mounting means for a fuel rail and injector assembly, said fuel rail and injector assembly comprising a fuel delivery rail, and a fuel injector having an inner fuel delivery channel and a mounting end, said mounting means comprising
a base plate, said base plate for mounting said mounting means onto a fuel delivery rail,
a fitting extending from said base plate, said fitting being insertable into said fuel delivery channel of said injector, and
clip means extending from said base plate at a distance from said fitting such that said clip means extend along an outer surface of said mounting end of said injector when said injector is mounted to said fuel rail, said clip means co-operating with retaining means on said outer surface of said mounting end.

11. Mounting means according to claim 10, wherein said fitting comprises sealing means associated to an inner surface of said fuel delivery channel of said injector.

12. Mounting means according to claim 11, wherein said fitting comprises at least one necking portion having a reduced outer diameter and wherein said sealing means comprise at least one o-ring seal mounted on said fitting in said necking portion.

13. Mounting means according to any one of claims 10 to 12, wherein said clip means comprises at least one tab having hook means, said hook means for engaging into a notch in said outer surface of said mounting end of said injector.

14. Mounting means according to claim 13, wherein said clip means comprises at least two tabs having hook means, said tabs extending from said base plate at different locations at the periphery of said fitting.

15. Mounting means according any one of claims 10 to 14, further comprising at least one index lug extending from said base plate for co-operating with an index notch of said mounting end of said injector.

Drawing