Long injector for fuel injection into an internal combustion engine

The present invention relates to a long injector for fuel injection into an internal combustion engine, and in particular to an electrical connection between a base portion and an extension portion of a long injector, wherein the long injector is formed by connecting the extension portion to the base portion.

In common internal combustion engines, fuel injector systems are used to inject highly pressurized gasoline directly into combustion chambers of the internal combustion engines. Therein an injector for fuel injection must be inserted deep into an internal combustion chamber of an internal combustion engine, in order to improve the efficiency of the engine. Such a fuel injector in common internal combustion engines typically has a length of about 90 mm. Due to the restricted space in the cylindrical volume inside the cylinder block and densely arranged equipment around the cylinder head, which also limits the space available outside the cylinder block, long injectors have been designed by connecting an extension portion to such a common fuel injector. In particular, by connecting an extension portion to a common fuel injector, the length of the fuel injector can be extended from about 90 mm to a length ranging from about 150 mm to about 190 mm.

The document US 7,213,578 B2 discloses a mounting structure for an injector for fuel injection into an internal combustion engine, wherein a fixing member is inserted into a hole of a cylinder head in an axial direction. Thus, the injector is fixed between the fixing member and the cylinder head. A connector portion of the fixing member is inserted into the hole of the cylinder head together with the fixing member, and the connector portion of the fixing member is connected to a connector portion of the injector. A first socket provided on an end of the connector portion of the fixing member opposite from the injector is disposed outside the cylinder head, wherein this socket is connected to a power source.

It is an object of the present invention to provide an improved long injector, which can easily be inserted deeply into an internal combustion engine.

This object is solved by the subject matter of the independent claims. Further advantageous features are subject matter of the dependent claims.

According to an embodiment of the invention, this object is solved by a long injector for fuel injection into an internal combustion engine. The long injector comprises a base portion and an extension portion. In the present context, a "long injector" is in particular understood to be an injector with a base portion and an extension portion, longitudinally extending the base portion .

The extension portion is electrically connected to the base portion, wherein an end of the extension portion comprises an electrically conductive terminal with one or more contact clips, wherein the one or more contact clips are spaced at a distance from each other or from a side wall of the electrically conductive terminal, wherein an end of the base portion comprises one or more electrical contacts, wherein each of the one or more electrical contacts is positioned at the end of the base portion in such a way, that each of the one or more electrical contacts can slide into a respective contact clip of the electrically conductive terminal when connecting the extension portion to the base portion, and wherein the electrically conductive terminal has a latch mechanism, wherein an electrical connection between the base portion and the extension portion is created, when each of the one or more electrical contacts is inserted into the re- spective contact clip and held by the latch mechanism.

Thereby, an improved long injector is provided, which can easily be inserted deeply into an internal combustion engine. In particular the one or more electrical contacts on the base portion and the respective contact clips on the electrically conductive terminal are located and orientated in such a way, that their outline, when they are connected to each other, lies within the cylindrical shape of the long injector. Thus, it can be ensured that the electrical connection between the base portion and the extension portion does not protrude out of the cylindrical shape of the long injector and the long injector can be inserted deeply into the cylindrical opening of the cylinder block of the engine. Therein the extension portion can be fixed onto the cylinder head and acts as a mechanical fixture of the base portion of the long injector. The latch mechanism of the electrical connection provides a mechanical stop during the assembly process of the extension portion to the base portion and stabilizes the assembly mechanically in such a way, that a stable electrical connection between the extension portion and the base portion is maintained.

Therein the long injector can further comprise an encapsulation body which encapsulates the electrical connection. The en ^¬ capsulation body provides a one-body design of the long injector and mechanically protects the electrical connection, wherein additionally the electrical connection is protected against ingress of solid objects and liquids in order to prevent corrosion that could lead to a destruction of the electrical connection. In one embodiment, the encapsulation body is an overmolded body. The overmolded encapsulation body in particular comprises or consists of a resin or a thermoplastic material. Preferably, the encapsulation body fixes the base portion to the extension portion such that the base portion and the extension portion are not nondestructively separable from one another. To put it differently, the base portion and the extension portion are non-detachably fixed to each other by means of the overmolded encapsulation body. In this way, the long injector can be handled as one piece during installation. With advantage, a particular precise positioning of the base portion to the extension portion is achievable.

Further the one or more contact clips can comprise an elastic material, wherein the latch mechanism is realized by the elastic material in such a way, that the one or more electric contacts are compressed by the elastic material of the one or more contact clips. Thus, the latch mechanism can be realized by the design of the contact clips, and thus by fewer components compared to a design, wherein the latch mechanism is realized by separate components within the electrically conductive terminal. Thereby material cost and process time of the assembly of the extension portion and the base portion can be reduced, whereby the overall costs of the long injector are reduced.

Further the end of the base portion may comprise one or more ribs that are positioned in such a way, that each of the one or more ribs can be inserted into a respective distance between two contact clips of the electrically conductive terminal or a respective distance between a contact clip and a side wall of the electrically conductive terminal. By the ribs the one or more contact clips can be stabilized during insertion of the electrical contacts and stably kept in the position, in which the electrical connection is created, and prevented from losing the electrical connection by expanding. This is also important during encapsulating the electrical connection, as the encapsulation material is injected with pressure and heat onto the electrical connection, in particular the electrical connection that is formed by the electrical contacts and the contact clips.

According to a further embodiment of the invention, a fuel injection system of an internal combustion engine is provided, which comprises a long injector as described above. The advantage of such a fuel injection system is that it comprises a long injector that can easily be inserted deeply into a combustion chamber of an internal combustion engine, wherein the extension portion is in particular fixed onto a cylinder head of the engine and acts as a mechanical fixture for the base portion of the injector.

Preferably, the long injector is shaped and configured such that the electrical connection is arrangeable inside a bore of the cylinder head of the engine. The electrical connection from the top of the extension portion to the base portion is preferably realized in such a way, that it does not protrude out of the cylindrical shape of the long injector.

According to one embodiment, the fuel injection system also comprises a fuel rail having an outlet port. Expediently, the fuel rail may be an elongated tubular body comprising a plurality of outlet ports, each outlet port in particular being assigned to a respective cylinder of the combustion engine. The long injector is hydraulically and mechanically coupled to the outlet port - in particular to one of the outlet ports - in nondestructively separable fashion. In particular the extension portion of the long injector is shifted into an injector cup which is fixed to the outlet port and may additionally be clamped or screwed to the injector cup in some embodiments. In one embodiment, the fuel delivery assembly comprises the cylinder head of the internal combustion engine and the electrical connection of the long injector is arranged in a bore of the cylinder head. In this way, the same base portions and fuel rails can be used for engines with differently shape cylinder heads by using long injectors with different extension portions.

According to a further embodiment of the invention, a vehicle is also provided, which comprises a fuel injection system that comprises a long injector as described above. The advantage of such a vehicle is that the long injector can easily be inserted deeply into an internal combustion chamber of an internal combustion engine, wherein the extension portion is fixed onto the cylinder head and acts as a mechanical fixture for the base portion of the injector and wherein the electrical connection from the top of the extension portion to the base portion is realized in such a way, that it does not protrude out of the cylindrical shape of the long injector. According to still a further embodiment of the invention, a method is provided for electrically connecting a base portion to an extension portion to produce a long injector for fuel injection into an internal combustion engine, wherein the method comprises the following steps: Providing an extension portion, wherein an end of the extension portion comprises an electrically conductive terminal with one or more contact clips, wherein the one or more contact clips are spaced at a distance from each other or from a side wall of the electrically conductive terminal, providing a base portion, wherein an end of the base portion comprises one or more electrical contacts, wherein each of the one or more electrical contacts is positioned at the end of the base portion in such a way, that each of the one or more electrical contacts can slide into a respective contact clip of the electrically conductive terminal when connecting the extension portion to the base portion, electrically connecting the extension portion to the base portion by inserting the one or more electrical contacts into the respective contact clips, until each of the one or more electrical contacts is held by a latch mechanism of the electrically conductive terminal.

Thereby, a method for producing an improved long injector, which can easily be inserted deeply into an internal combustion engine, is provided.

In particular by providing an extension portion, comprising an electrically conductive terminal, which comprises one or more contact clips and a base portion, comprising one or more electrical contacts, wherein the one or more electrical contacts on the base portion and the respective contact clips on the electrically conductive terminal are located and orientated in such a way, that it can be ensured that the electrical connection between the base portion and the extension portion does not protrude out of the cylindrical shape of the long injector. Thus the long injector can be inserted deeply into the cylindrical opening of the cylinder block of the engine.

The method may further comprisea step of encapsulating the electrical connection. By encapsulating the electrical con- nection an encapsulation body is provided, through which a one-body design of the long injector can be provided, which mechanically protects the electrical connection, wherein ad ^¬ ditionally the electrical connection is protected against ingress of solid objects and liquids in order to prevent corrosion that could lead to a destruction of the electrical connection. Preferably, the method comprises a step of overmolding the electrical connection - in particular with a resin or a thermoplastic material - to produce the encapsulation body which encapsulating the electrical connection between the base portion and the extension portion.

Further, the one or more contact clips can comprise an elastic material, wherein the step of electrically connecting the extension portion to the base portion comprises compressing the one or more electric contacts by the elastic material of the one or more contact clips. Thus, the latch mechanism can be realized by the design of the contact clips, and thus by fewer components compared to a design, wherein the latch mechanism is realized by separate components within the electrically conductive terminal. Thereby material cost and process time of the assembly of the extension portion and the base portion can be reduced, whereby the overall costs of the long injector are reduced.

The method may further comprise the step of providing one or more ribs on the end of the base portion that are positioned in such a way, that each of the one or more ribs can be inserted into a respective distance between two contact clips of the electrically conductive terminal or a respective distance between a contact clip and a side wall of the electrically conductive terminal. By the ribs the one or more contact clips can be stabilized during insertion of the electrical contacts and stably kept in the position in which the electrical connection is created and prevented from losing the electrical connection by expanding. This is also important during encapsulating the electrical connection, that may be an overmolding process with a resin or thermo-plastic material, as the encapsulation material is injected with pressure and heat onto the electrical connection, in particular the electrical connection between the electrical contacts and the contact clips.

Embodiments of the invention will now be described with reference to the accompanying drawings . Figure 1 illustrates a schematic drawing of a long injector for fuel injection into an internal combustion engine, according to embodiments of the present invention;

Figure 2a illustrates a schematic drawing of the electrical connection between the extension portion and the base portion of a long injector before encapsulating the electrical connection, according to embodiments of the present invention;

Figure 2b illustrates a schematic drawing of the electrical connection between the extension portion and the base portion of a long injector after encapsulating the electrical connection, according to embodiments of the present invention;

Figure 3 is a flow chart illustrating a method for elec- trically connecting a base portion to an extension portion to produce a long injector for fuel injection into an internal combustion engine, according to embodiments of the present invention;

Figure 1 illustrates a schematic drawing of a long injector 1 for fuel injection into an internal combustion engine, according to embodiments of the present invention.

In common internal combustion engines, an injector for fuel injection must be inserted deep into the internal combustion chamber in order to improve the efficiency of the engines. Due to the restricted space inside the cylinder block and the densely arranged equipment around the cylinder head, which limits the space available outside the cylinder block, long injectors have been developed to insert the injector deeply into the cylinder head of internal combustion chambers. In particular by adding an extension portion to a base portion of an injector a long injector with a length in the range of about 150 mm to about 190 mm is provided.

According to the embodiments shown in Figure 1, the long injector

1 comprises a base portion 2 and an extension portion 3, wherein an end 9 of the base portion 2 is connected mechanically and electrically to an end 4 of the extension portion 3. An electrical connection 12 is realized from the end 9 of the base portion 2 to the top of the extension portion 3, where an external power source can be connected to the injector with a connector device by using a standard plug connector.

Figure 2a illustrates a schematic drawing of the electrical connection 12 between the extension portion 3 and the base portion

2 of a long injector 1 before encapsulating the electrical connection, according to embodiments of the present invention.

As shown in Fig. 2a, the base portion 2 comprises an end 9 facing to the extension portion 3 of the long injector 1, on which two electrical contacts 10 are provided. The extension portion 3 comprises an end 4 facing the base portion 2, on which an electrically conductive terminal 5 with two contact clips 6 is provided. The contact clips 6 are spaced at a distance 7 from each other and from a side wall 8 of the electrically conductive terminal 5, and thus, the contact clips 6 are provided in a fork design. Therein the contact clips 6 are positioned and orientated in such a way, that they do not protrude out of the cylindrical shape of the injector. Furthermore the two electrical contacts 10 are positioned relative to the respective contact clips 6 in such a way, that each of two electrical contacts 10 can slide into a respective contact clip 5 of the electrically conductive terminal 5 when connecting the extension portion 3 to the base portion 2. Further, the electronically conductive terminal 5 of the extension portion 3 has a latch mechanism 11. Therein, an electrical connection 12 is created, when each of the two electrical contacts 10 is inserted into the respective contact clip 5 and held by the latch mechanism 11.

Thus, the electrical connection between the base portion and the extension portion does not protrude out of the cylindrical shape of the long injector and the long injector can be inserted deeply into the cylindrical opening of the cylinder block of the engine and thus, an improved long injector is provided, which can easily be inserted deeply into an internal combustion engine.

According to the embodiment shown in Fig. 2a, the two contact clips 6 comprise an elastic material 14, wherein the latch mechanism 11 is realized by the elastic material 14 of the contact clips 6 in such a way, that the two electric contacts 10 are compressed by the elastic material 14 of the two contact clips 6. However, that the latch mechanism 11 is realized by the elastic material 14 of the contact clips 6 should merely be understood as an example, and the latch mechanism 11 can also be realized by a plurality of other components, for example by a mechanical latch mechanism. The end 9 of the base portion 2 further comprises three ribs 15 that are positioned in such a way, that each rib 14 can be inserted into a distance 7 between two contact clips 6 of the extension portion 3 or a distance 7 between a contact clip 6 and a side wall 8 of the electrically conductive terminal 5. Therein the ribs can be formed by plastic material within the base portion 2.

Figure 2b illustrates a schematic drawing of the electrical connection 12 between the extension portion 3 and the base portion 2 of a long injector 1 after encapsulating the electrical connection, according to embodiments of the present invention.

As shown in Figure 2b, the encapsulation body 13 formed by encapsulating of the electrical connection encloses the end 9 of the base portion 2 that is attached to the end 4 of extension portion 3 by the electrical connection 12, wherein the body can consist of a resin material or a thermo-plastic material used in an overmolding process. The design realizes a single body for the injector, wherein both portions are mechanically connected in a stable way by the encapsulation body 13 that can only be dismantled with destruction.

Figure 3 is a flow chart illustrating a method for electrically connecting a base portion 2 to an extension portion 3 to produce a long injector 1 for fuel injection into an internal combustion engine, according to embodiments of the present invention.

According to Figure 3, the process starts with step 20. In step 21 an extension portion is provided, wherein an end of the extension portion comprises an electrically conductive terminal with one or more contact clips, wherein the one or more contact clips are spaced at a distance from each other or from a side wall of the electrically conductive terminal.

In step 22 a base portion is provided, wherein an end of the base portion comprises one or more electrical contacts, wherein each of the one or more electrical contacts is positioned in such a way, that each of the one or more electrical contacts can slide into a respective contact clip of the extension terminal when connecting the extension portion to the base portion.

In step 23 the extension portion is electrically connected to the base portion, by inserting the one or more electrical contacts into the respective contact clip until each of the one or more electrical contacts is held by a latch mechanism of the electronically conductive terminal. Thus, the electrical connection is created, when each of the one or more electrical contacts is inserted into the respective contact clip and held by the latch mechanism.

Further, the method shown in Fig. 3 comprises the additional step 24 of encapsulating the electrical connection with an encap- sulation body. Encapsulating the electrical connection can be an overmolding process with a resin or thermo-plastic material.