Holding component and fuel injection assembly for an internal combustion engine

The present disclosure relates to a holding component for securing a fuel injector to an injector cup. It also relates to a fuel injection assembly for an internal combustion engine, particularly but not exclusively, for a gasoline direct injection internal combustion engine, comprising the holding component.

Fuel injection assemblies are widely used for injecting fuel into an internal combustion engine, particularly having an injector for each cylinder of a multi-cylinder engine in which the fuel is supplied from a reservoir in the form of a common rail to which each of the injectors is connected. The assembly is also suitable for use in a single cylinder engine. In known systems the injectors are secured directly to the cylinder head of the engine to project into the combustion chamber. Such arrangements have a disadvantage in that noise generated by the injection and combustion process is transmitted through the engine to the exterior. In order to reduce noise transmission one known solution is to isolate the injector from direct mechanical connection with the engine. One solution to this problem is to suspend the injector in a fuel rail injector cup by means of a holding element, commonly called a fork clip. The injector cup itself is secured to the fuel rail and the engine. In this way there is no direct mechanical coupling between the injector and the engine components.

A further problem arises in that it possible for the fuel injector to pivot about the axis of the injector cup during assembly. It is necessary, however, for the angular position of the fuel injector to be precisely positioned relative to the injector cup so that the fuel injector fuel output is in the correct position for fuel injection into the combustion chamber. In the known arrangements this is achieved by means of a further component known as an indexing clip. Such arrangements are shown for example in US Patent No.8, 479, 710 and WO 2015/135732.

US 2015/330347 Al discloses a system, which is used especially as a fuel injection system for the high-pressure injection in internal combustion engines. It includes a fuel distributor and a plurality of fuel injectors. Each fuel injector is situated on a cup of the fuel distributor. At least one of the fuel injectors is fastened to the associated cup by a holding element. The holding element has an at least essentially straight first leg and an at least essentially straight second leg. The cup includes at least one recess, which extends through a wall of the cup. The first leg and the second leg are guided through the at least one recess. Furthermore, the connection sleeve of the fuel injector has a collar, which is braced on the first leg of the holding element and on the second leg of the holding element in order to secure the fuel injector on the cup. This makes it possible to fasten the fuel injector on the cup in a reliable manner.

It is an object to of the present disclosure to provide an improved holding component. It is a further object of the present disclosure to provide a fuel injection assembly which has less components than the known arrangement, in which the holding element and the indexing clip are combined into one component.

This object is achieved by a holding component and a fuel injection assembly according to the independent claims. Further advantages, advantageous embodiments and developments are specified in the dependent claims, in the following description and in the drawings . The present disclosure provides a holding component for securing a fuel injector to an injector cup. It comprises a generally U-shaped holding element having two generally parallel sup ^¬ porting arms for engaging opposite sides of an annular groove in a fuel injector to secure the fuel injector in an injector cup. To put it differently, the two generally parallel supporting arms are adapted - i.e. they are shaped and arranged - to engage opposite sides of an annular groove in a fuel injector to secure the fuel injector in an injector cup.

The holding component further includes two resilient arms extending from a base part of the holding component for engaging the outer surface of the injector cup. In other words, the two resilient arms are adapted to engage the outer surface of the injector cup.

The holding element also has at least one depending leg engageable in a corresponding receiving part on the fuel injector to accurately position the fuel injector angularly relative to the injector cup.

According to the present disclosure there is also provided a fuel injection assembly having a longitudinal axis and comprising an elongate fuel injector having a fuel inlet port and a fuel outlet port, an injector cup, and a holding component for securing the fuel injector in the injector cup.

The injector cup comprises a generally cylindrical body extending along the axis and having an upper and a lower end. The cup has a recess at its lower end adapted to receive a fuel inlet port of the fuel injector. In particular, the fuel inlet port is received in the recess. A first opening is formed or first openings are formed in the peripheral wall of the injector cup for receiving a holding element of the holding component. In particular, the holding element is received in the first opening (s) .

The holding element is generally U-shaped having two generally parallel supporting arms engaging opposite sides of an annular groove in the fuel injector to secure the fuel injector in the injector cup. The holding component further includes two re- silient arms extending from a base part of the holding component and engaging the outer surface of the injector cup and at least one depending leg engaged in a corresponding receiving part on the fuel injector to accurately position the fuel injector angularly relative to the injector cup.

Embodiments in accordance with this disclosure have the advantage of a low-cost solution to the known problems both because of the reduction in the number of individual components, the lower cost of production of the component and the speeding up of assembly. Assembly of the fuel injector and injector cup is a simple two stage operation; the injector is inserted in the injector cup, the holding component is pushed into place to locate the injector in the injector cup and then the depending leg is clipped into place to give accurate rotary alignment of the injector and the injector cup.

In a preferred embodiment, the two parallel supporting arms of the holding element comprise a double thickness of material, the two resilient arms being formed of a single thickness of material .

In a further embodiment, the roots of the resilient arms extend from a resilient web part of the base part which enable the resilient arms to move in the direction of their longitudinal extent . In yet another embodiment, the two resilient arms have inwardly extending projections at their free ends which, when the holding component is inserted in the injector cup, engage the injector cup to lock the holding component in position.

In a preferred embodiment, the holding element is a one-piece component formed from a sheet metal material. In another em ^¬ bodiment the holding component is formed of a moulded plastics material. When formed of a sheet material, the two parallel supporting arms of the holding element comprise a double thickness of material, the two resilient arms being formed of a single thickness of material . For example in this case, the double thickness of material may be achieved by folding the material over on itself.

In another embodiment, the holding component has two depending legs in spaced parallel relationship, each leg being engageable in a corresponding receiving part on the fuel injector. In an assembled state of the fuel injector assembly, each leg may expediently engage the corresponding receiving part on the fuel injector. Preferably, the receiving parts comprise recesses in the fuel injector. In another preferred embodiment, the recesses are formed in a plastics component part of the fuel injector. In this way, the recesses can be preformed in a mould from which the plastics component is manufactured.

A preferred embodiment of the present invention will now be described by way of example with reference to the accompanying drawings, in which: -

Figure 1 shows a fuel injector assembly of an injector cup and a fuel injector, Figure 2 shows a holding component for securing the fuel injector to the injector cup,

Figure 3 shows a schematic view of the holding component po- sitioned in the injector cup.

In this description reference is made to upper and lower ends but this nomenclature is used solely for descriptive convenience. In the installed condition, the orientation of the assembly depends upon the particular configuration.

Figure 1 shows a fuel injector cup 2 for receiving a fuel injector 4, the cup comprising a generally cylindrical body. The cup 2 is fastened to a tubular fuel rail (not shown) in a mechanically secure and hydraulically fluid tight manner. For example, the cup 2 may have and one or more openings adjacent its upper end through which the cup 2 is fastened to the fuel rail. In the illustrated embodiment, the cup 2 has an arcuate cutaway 6 through which the cup 2 is fastened to the fuel rail. At its lower end the cup 2 has an opening 8 for receiving the fuel inlet 10 of the fuel injector 2. The fuel injector inlet 10 engages with the hydraulic connection to the fuel rail to provide a direct fuel path between the common rail reservoir and the fuel injector 4. The fuel injector has a annular groove 11 which is engageable by a holding component 14, described hereinafter, which locates the fuel injector securely in the injector cup 2.

Referring now to Figure 2 there is shown a holding component 14 formed by shaping from a resilient sheet metal material. The component 14 has a base part 16 from which two supporting arms 18 extend in spaced generally parallel relationship. The arms 18 are formed of a double thickness material by folding the material over on itself as can seen from the free ends 20. The base part 16 also has depending therefrom two legs 22 which are adapted to engage in corresponding recesses in a part of the fuel injector 4 when the holding component secures the fuel injector 4 to the injector cup 2.

Extending from the base part 16 is a curved web 24, U-shaped in cross-section, and, from a part 26 of the web remote from the base part 16, two resilient arms 28 extend to lie generally on the outer side, but spaced from, the supporting arms 20. The resilient arms 28 lie on the outside of the injector cup 2 and are resiliently biased inwardly so as to contact the exterior of the injector cup 2. At their outer free ends 30, the resilient arms 28 have inwardly projecting latches 32 which, when the holding component 14 is inserted in the injector cup 2, clip into corresponding recesses or detents in the injector cup surface to thereby lock the holding component 14 to the injector cup 2. Although shown in the schematic sketch of Figure 2 as straight, it will be appreciated that the resilient arms 28 will be shaped to the general profile of the injector cup 2.

Referring also to Figure 3, this shows a schematic view of the holding component 14 inserted in the injector cup 2. In operation, when securing a fuel injector 4 in the injector cup 2, the inlet port 10 of the injector 4 is first inserted in the injector cup 2 and the supporting arms 18 of the holding component 14 are inserted through openings in opposed sides of the injector cup wall so that the supporting arms 18 support the fuel injector 4 by engaging on opposite sides of the groove 11 in the fuel injector 4.

Thereafter, the supporting arms 18 are fully inserted in the injector cup 2 until the base part 16 abuts the outer wall of the injector cup 2. Thereupon, the angular position of the fuel injector 4 is adj usted until the recesses therein are aligned with the two legs 22. Then, by pressing on the web part 26 against the resilient bias of the web 24, the resilient arms 28 are moved longitudinally in the direction of the arrow A until the latches 32 engage in detents or catches on the injector cup 2. In this way, the two legs 22 are firmly located in the recesses in the fuel injector 4 to fasten the fuel injector securely in the correct orientation.

The holding component 14 thus serves the function of the two or more components of the known prior art, namely the holding element and the indexing clip. The use of the single component therefore greatly reduces assembly time on the production line, and eliminates a potential source of errors when two or more components have to be used. It also reduces the cost of inventory and logistics in transporting compared with using two or three separate components. Manufacturing the holding component from a single flat sheet of metal by simply folding and shaping the material into the component is particularly advantageous in providing a very cost-effective and speedy solution.

In an alternative embodiment, it is possible for the holding component to be formed of a moulded plastics material.