EP1780403B1 - Fuel injection valve - Google Patents

Description

State of the art

The invention is based on a fuel injection valve according to the preamble of the main claim.

To compensate for manufacturing tolerances of a fuel injection valve various types of installation are known in the art.

From the DE 197 35 665 A1 For example, a fuel injection valve is known, wherein a compensation element, which consists of a support body having a dome-shaped support surface is used to compensate for tolerances in the manufacture and in the assembly of the fuel injection valves. The fuel injection valve is supported on this compensating element in a receiving bore of a cylinder head. Since the fuel injection valve rests on the spherical shaped Kalottenfläche with a support surface, the fuel injection valve can be mounted to a certain angle to the axis of the receiving bore and firmly into the receiving bore by suitable means such. B. a clamping claw, are pressed. By this arrangement, an adjustment of the fuel supply lines is possible, however requires the support body a complex production and a precisely manufactured spherical surface. The rigid support body can not be compressed, and it can thus take place no compensation in the axial direction of the receiving bore of the cylinder head. The compensation of tolerances can continue to take place only on the given geometry of the spherical surface.

Another solution to compensate for tolerances is according to DE 101 40 797 A1 proposed to provide a compensating element in the form of an intermediate ring, which is arranged between the valve housing of the fuel injection valve and a wall of a receiving bore of the cylinder head. The intermediate ring further has webs which extend along the valve housing and on which support segments are fixed, which surround the valve housing, whereby the valve housing is spaced from the wall of the receiving bore. However, in this arrangement, with low inclination, significant lateral forces are produced during installation on the fuel injector and gaskets.

Furthermore, in the DE 197 35 665 A1 a fuel injector is described, which uses a tubular intermediate piece, which is arranged between the fuel inlet opening of each fuel injection valve and the associated fuel outlet opening to compensate for positional and angular deviations resulting from the manufacturing tolerances and assembly-related tolerances and which with the fuel Inlet opening of the associated fuel injection valve and the fuel outlet opening of the fuel rail sealing and is movably connected within predetermined limits, so that the inlet portion of the fuel injection valve via the intermediate piece on the fuel rail is flexibly mounted. The disadvantage here, however, that two sealed with respective O-rings seal with the resulting disadvantages, such as the resulting costs and the additional risk of leakage arise. Furthermore, the intermediate piece is an additional component which requires appropriate space, which is particularly at central installation position of disadvantage, since the installation space is very cramped.

In the DE 103 38 715 A1 a fuel injection valve is proposed with a compensation element for supporting the valve in a cylinder head of an internal combustion engine, wherein the compensation element is annular and is disposed between the valve housing of the fuel injection valve and a wall of a receiving bore of the cylinder head. The compensation element has at least two legs, which are supported on the fuel injection valve and the cylinder head. However, in this embodiment, a disadvantage that also here an additional element, namely the support element and the corresponding space are provided for it.

A disadvantage, therefore, in all fuel injection valves mentioned above, that they require a complex construction and additional components must be used to compensate for tolerances, which increases the cost accordingly.

Advantages of the invention

From the EP 1 445 474 A1 A fuel injection valve is already known, which is particularly suitable for the direct injection of fuel into a combustion chamber of an internal combustion engine. The fuel injection valve has a nozzle body which can be inserted into a recess of a cylinder head. In addition, the valve housing has an inlet-side end, which is connectable to a connection piece of a fuel distributor line, wherein the inlet-side end is formed as an elongated connection sleeve. The connecting sleeve is formed as a flexible bellows or corrugated bellows with a plurality of axially successive folds or waves.

From the EP 1460 264 A1 A fuel injection system is already known, in which the fuel injection valves are connected in each case via elongated connecting sleeves with connecting pieces of a fuel distributor line. The connecting sleeves are characterized in that they have a constant inner diameter and a large wall thickness, so that there is a rigid connecting component, the two axial ends to seal against the fuel rail and the nozzle body of the fuel injection valve, a sealing arrangement with an O-ring and a locking ring having. Apart from the two axial end regions with the sealing arrangements, the connecting sleeve also has a constant outside diameter.

From the DE 101 48 824 A1 A fuel injection valve is already known, which is particularly suitable for the direct injection of fuel into a combustion chamber of an internal combustion engine. The fuel injection valve has a nozzle body which can be inserted into a recess of a cylinder head. In addition, the valve housing has an inlet-side end, which is connectable to a connection piece of a fuel distributor line, wherein the inlet-side end is provided with a longitudinal opening into which an elongated connection sleeve can be used as a separate individual component. This connection sleeve serves to connect the fuel injection valve to the fuel distributor line. In this case, the connecting sleeve is arranged so that a flow path of the fuel through the Brennstoffeinspritzventli length and diameter moderately formed such that the frequency of natural oscillations, which are excited by the fuel injection valve flowing through the fuel, is matched to the closing intervals of the fuel injection valve.

From the US 2005/0211225 A1 A fuel injection valve is already known, which is particularly suitable for the direct injection of fuel into a combustion chamber of an internal combustion engine. The fuel injection valve has a nozzle body which can be inserted into a recess of a cylinder head. In addition, the valve housing has an inlet-side end, which is connectable only indirectly to a connecting piece of a fuel distributor line, namely, the inlet-side end is formed so that an elongated connection sleeve can be plugged as a separate attachment. This connection sleeve is used for indirectly connecting the fuel injection valve to the fuel distributor line. The fuel injector is insertable into a stepped receiving bore of the cylinder head, wherein the fuel injection valve rests with a collar of the nozzle body on a sealing ring which is introduced on a stage of the receiving bore.

In contrast, the fuel injection valve according to the invention with the characterizing feature of the main claim has the advantage that due to the elongated design of the connection sleeve for the purpose of tolerance compensation this has a low resistance moment and deformed even at low shear forces accordingly. Thus, the tolerance compensation is effected in a simple manner and without expensive additional parts.

In order to further reduce the moment of resistance, the connecting sleeve preferably has a constriction, which can be arranged at different positions and with different lengths on the connecting sleeve.

Especially advantageous is the support of the fuel injection valve in the cylinder head. When the fuel injector is on a slope of z. B. 45 ° is supported in a correspondingly congruent formed recess of the cylinder head, this brings the advantage that the fuel injector is centered during installation simultaneously. The deformation of the connection sleeve for tolerance compensation takes place only under the action of the hold-down force and the pressure in the so-called rail, which acts on the cross section of the rail cup instead. The fuel injector must absorb only small lateral forces that do not lead to a change in its function or its strength.

The fuel injection valve according to the invention therefore brings particular advantages during installation, which is especially true for central installation, and reduced in the production of the number of parts to be assembled.

drawing

Fig. 1A

einen schematischen Querschnitt durch ein Brennstoffeinspritzventil gemäß dem Stand der Technik;

Fig. 1B

einen schematischen Querschnitt durch ein weiteres Brennstoffeinspritzventil gemäß dem Stand der Technik;

Fig. 2

ein Ausführungsbeispiel des erfindungsgemäßen Brennstoffeinspritzventils;

Fig. 3A - 3F

verschiedene Ausführungsbeispiele von Anschlusshülsen des erfindungsgemäßen Brennstoffeinspritzventils;

Fig. 4A - 4E

schematische Querschnitte durch weitere Ausführungsbeispiele von Anschlusshülsen des Brennstoffeinspritzventils; und

Fig. 5A, 5B

Ausschnitte eines abspritzseitigen Endes des erfindungsgemäßen Brennstoffeinspritzventils.

Embodiments of a fuel injection valve according to the invention and of a fuel injection valve according to the prior art are shown in simplified form in the drawing and are explained in more detail in the following description. Show it:

Fig. 1A

a schematic cross section through a fuel injection valve according to the prior art;

Fig. 1B

a schematic cross section through another fuel injection valve according to the prior art;

Fig. 2

an embodiment of the fuel injection valve according to the invention;

Figs. 3A - 3F

various embodiments of connection sleeves of the fuel injection valve according to the invention;

Fig. 4A - 4E

schematic cross sections through further embodiments of connection sleeves of the fuel injection valve; and

Fig. 5A, 5B

Cutouts of a discharge end of the fuel injection valve according to the invention.

Description of the embodiments

Fig. 1A shows a schematic cross section through a fuel injection valve 1 according to the prior art, which uses an intermediate piece 17 to compensate for manufacturing tolerances and assembly-related tolerances. A combustion chamber 18 of the internal combustion engine is closed by means of a cylinder head 12. The cylinder head 12 has a receiving bore or recess 14 into which a discharge-side end 8 of a fuel injection valve 1 can be inserted. The recess 14 is sealed to a ring seal 19 against the combustion gases of the combustion chamber 18.

On the side remote from the combustion chamber 18, a recess 20 formed in the cylinder head 12 adjoins the recess 14 and accommodates a flange 21 of the fuel injection valve 1 inserted into the recess 14. The flange 21 rests on a flat support surface 22 of the cylinder head 12 and is pressed against the support surface 22 of the cylinder head 12 by means of a hold-down device designed as a clamping claw 23. The holding force exerted by the clamping claw 23 is greater than the opposing force exerted by the combustion pressure of the combustion gases in the combustion chamber 18, so that the discharge-side end 8 of the fuel injection valve 1 is securely fixed to the cylinder head 12 even at high combustion pressure.

To supply the fuel injection valve 1, a fuel rail 24 is provided. The fuel rail 24 is tubular and extends along an axis 26 oriented perpendicular to the longitudinal axis 25 of the fuel injector 1 and the recess 14 of the cylinder head 12. The fuel rail 24 has at the position of each fuel injector 1 a connecting piece 27, formed in the form of a stepped hollow cylinder and having a guide portion 28 which communicates via a connecting channel 29 with the main channel 30 of the fuel rail 24 in communication.

In the region of the connection piece 27, the fuel distributor line 24 has a fuel outlet opening 31 for each fuel injection valve 1. Downstream of the fuel outlet port 31 of the fuel rail 24, the intermediate piece 17 connects, which supplies the fuel to a fuel inlet port 32 at an inlet portion 33 of the fuel injection valve 1. The intermediate piece 17 has an upstream, tapered portion 34 which is insertable into the guide portion 28 of the connecting piece 27 and is sealed by a designed as an O-ring first sealing member 35 relative to the connecting piece 27 of the fuel rail 24.

The upstream tapered portion 34 of the intermediate piece 17 is slidable in the guide portion 28 of the connecting piece 27 by the first sealing member 35 slides on the inner wall of the guide portion 28 along. Furthermore, that is Intermediate piece 17 with respect to the connecting piece 27 pivotable within predetermined limits, wherein the pivoting gap between the gap between the upstream tapered portion 34 of the intermediate piece 17 and the guide portion 28 of the connecting piece 27 is compensated by the first sealing member 35. The intermediate piece 17 further has a downstream portion 36, on the inner diameter of a guide portion 37 is formed for the inlet portion 33 of the fuel injection valve 1.

The inlet section 33 has a second sealing element 38 designed as an O-ring, which seals the gap distance between the downstream section 36 and the inlet section 33 of the fuel injection valve 1. The inflow portion 33 is also slidable in the guide portion 37 by the second seal member 38 slides on the inner wall of the downstream portion 36 of the intermediate piece 17 along. Furthermore, the inlet section 33 is pivotable with respect to the intermediate piece 17 within predetermined limits, wherein the sealing element 38 is slightly deformed during pivoting and compensates for the change in the gap distance between the downstream portion 36 of the intermediate piece 17 and the inlet portion 33 of the fuel injection valve 1 accordingly.

Due to the displaceable and pivotable arrangement of the intermediate piece 17 on the connecting piece 27 on the one hand and the displaceable and pivotable arrangement of the inlet portion 33 of the fuel injection valve 1 on the intermediate piece 17 on the other hand is an articulated bendable and shortened or extendable Telescope connection between the fuel rail 24 and the fuel injection valve 1 achieved, which allows flexible mounting of the fuel rail 24. Installation-related angular or positional offset of the inlet section 33 can be compensated by means of the intermediate piece 17. However, the provision of the intermediate piece, as already mentioned, structurally complex, and the use of two sealing elements leads to the already mentioned problems associated with a possible leakage.

Fig. 1B shows a schematic partial cross-section through another fuel injection valve 1 according to the prior art, which has a standard length. This in Fig. 1B illustrated fuel injector 1 is designed in the form of a direct-injection fuel injector, which is used for direct injection of fuel into a combustion chamber of a non-illustrated, in particular mixture-compression spark-ignition internal combustion engine in a valve seat of a cylinder head. The fuel injection valve 1 has at an inlet end 2 a plug connection to a receiving socket of a fuel distributor line 3, which is sealed by a gasket 4 between the fuel distributor line 3 and a supply nozzle 5 of the fuel injection valve 1. The fuel injection valve 1 has an electrical connection 6 for an electrical contact for actuating the fuel injection valve 1.

Compared to the fuel injection valve 1 of the standard length is in Fig. 2 the fuel injection valve 1 according to the invention shown, which also at a supply end 2, a plug connection to a receiving socket of a fuel distribution line 3, which is not shown here, has. A gasket 4 is provided on a supply pipe 5 to seal the fuel injection valve 1. Furthermore, the fuel injection valve 1 according to the invention also has an electrical connection 6. The inlet-side end 2 of the fuel injection valve 1 is designed as an elongated tube to provide a low moment of resistance and be deformable under the action of radial forces, whereby manufacturing tolerances are compensated. At a discharge-side end 8 of the fuel injection valve can be inserted into a recess of a cylinder head nozzle body 9 is formed. A the inlet-side end of the fuel injection valve 1 forming and running as part of the valve housing connection sleeve 7 is z. B. formed by deep drawing. The connecting sleeve 7 and the electrical connection 6 can continue to be encased with a plastic extrusion.

Figs. 3A and 3F show various embodiments of connection sleeves 7 of the fuel injection valve according to the invention 1. The connection sleeve 7 may be provided in various forms. In Fig. 3A a connection sleeve 7 is shown, which has a constriction 10 in a remote from the supply pipe section 5, which extends over about 1/5 of the total length of the connection sleeve 7. On the other hand shows Fig. 3B a connecting sleeve 7 with constant diameter and constant wall thickness, wherein the diameter, the wall thickness and the length of the connecting sleeve 7 for the moment of resistance are decisive. In Fig. 3C is a connection sleeve 7 shown, in which the constriction extends over almost the entire length of the tube.

Fig. 3D shows a connection sleeve 7, the z. B. is formed in sections in the form of a bellows or shaft tube. Fig. 3E represents a connection sleeve 7, wherein the inner tube diameter is constant, but the wall thickness of the connecting sleeve 7 varies over the length thereof. Fig. 3F shows a connection sleeve 7, which similar to the in Fig. 3A shown connecting sleeve 7 is, but with the difference that the constriction 10 is provided in a central portion and extends over about 1/4 of the total length of the connecting sleeve 7.

Fig. 4A to 4E are schematic cross sections and partial sections through further embodiments of connection sleeves 7 of the fuel injection valve 1, wherein FIGS. 4A and 4B each show connection sleeves 7, which are designed with different diameter steps, ie the connection sleeve 7 has different constrictions 10, 11 of different diameters. On the other hand shows Fig. 4C a connecting sleeve 7, whose shape is characterized by a conical shape. In Fig. 4D Furthermore, a connection sleeve 7 is shown, which has two oppositely tapered portions 40 which are separated by a constriction 10 therebetween. Ultimately, in Fig. 4E a connecting sleeve 7 is shown, which has a convex portion 41.

A further alternative embodiment of the connection sleeve 7 has a concave shape, which is indicated by the dashed line 42 in FIG Fig. 4E is indicated. The Embodiments illustrate that in order to reduce the moment of resistance of the connecting sleeve 7, many possibilities are given by a corresponding embodiment of the same; the constriction 10 can be arranged at different positions and with different lengths on the connection sleeve 7; the connecting sleeve 7 can be designed with a constant diameter and a constant wall thickness, the diameter, the wall thickness and the length of the connecting sleeve 7 then being decisive for the moment of resistance or the connecting sleeve 7 can be designed with a constant inner or outer diameter and the wall thickness can vary. In any case, a deformation for tolerance compensation is made possible by the inventive design. The connection sleeve 7 may be made by deep drawing or rotary swaging.

Figs. 5A and 5B show sections of a discharge-side end 8 of the fuel injection valve 1 according to the invention, which show various support options of the fuel injection valve 1 in a cylinder head 12. According to the in Fig. 5A shown embodiment, a recess 14 which is provided in the cylinder head 12 for receiving the nozzle body 9 of the fuel injection valve 1, a z. B. at an angle of 45 ° beveled surface 15. The nozzle body 9 of the fuel injection valve 1 also has a beveled at an angle of 45 ° surface 16. The two surfaces 15, 16 are formed congruent shape and abut each other. In contrast, according to the in Fig. 5B However, the fuel injection valve 1 but also directly rest on a formed in the recess 14 of the cylinder head 12 plane surface 13 or be supported. The provision of the tapered surfaces 15, 16, in particular at an angle of 45 °, has the advantage that the fuel injection valve 1 is centered.

Claims (5)

1. Fuel injection valve (1), in particular for the direct injection of fuel into a combustion chamber (18) of an internal combustion engine, having a nozzle body (9) which is insertable into a recess (14) of a cylinder head (12), and having a valve housing with an inflow-side end (2) which is connectable to a connecting piece (27) of a fuel distributor line (24), wherein the inflow-side end (2) is in the form of an elongate connector sleeve (7),
   characterized
   in that the connector sleeve (7) is formed as part of the valve housing and, on its end which faces toward the fuel distributor line (24), there is formed a feed line connector (5) on which there is provided a seal (4) which is insertable into the connecting piece (27), and
   in that the connector sleeve (7) has at least one narrowed portion (10) for reducing its section modulus such that said connector sleeve is deformable under the action of radial forces, and
   in that the nozzle body (9) has, on its section that can be received in the cylinder head (12), a flat surface by way of which the fuel injection valve (1) lies directly on a flat surface (13) formed in the recess (14) of the cylinder head (12).
2. Fuel injection valve (1) according to Claim 1, characterized in that the connector sleeve (7) has a constant internal diameter, wherein the wall thickness of the connector sleeve (7) varies over its length.
3. Fuel injection valve (1) according to either of Claims 1 and 2, characterized in that the connector sleeve (7) is of thin-walled form.
4. Fuel injection valve (1) according to one of Claims 1 to 3, characterized in that the connector sleeve (7) is produced by deep-drawing or rotary swaging.
5. Fuel injection valve (1) according to one of Claims 1 to 4, characterized in that the fuel injection valve (1) is surrounded by an injection-moulded plastics encapsulation.

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