EP2097635B1 - Fuel injection valve and fuel injection system - Google Patents

Abstract

A fuel injector, especially for the direct injection of fuel into a combustion chamber of an internal combustion engine, includes a nozzle body able to be inserted into a recess of a cylinder head, a valve housing, a plug abutting the valve housing, and at least one fixation element, which fixes the nozzle body in its position in the recess, the fixation element extending from a connection region (28) between the valve housing and the plug on the spray-discharge side. The at least one fixation element has a reinforcement having a spherical contour at an outer periphery, the reinforcement being formed by at least one outwardly projecting element having an outwardly curving end face and/or having a planar end face.

Description

State of the art

The invention relates to a fuel injection valve according to the preamble of claim 1 and of a fuel injection system according to the preamble of claim 12.

Since only a few high-pressure injection valves spray the fuel jet actually in the extension of the valve longitudinal axis, but usually the spray is inclined to the longitudinal axis of the valve, which also in multi-hole valves, the injection holes are arranged predominantly asymmetric, it is important, the high-pressure injection valve in the cylinder head, in which it is used to fix so that no rotation of the valve can take place and the spray angle always corresponds to the interpretation.

For example, known solutions for fixing a high-pressure injection valve in a cylinder head include providing a rib at a portion of the outer circumference of the valve body which is inserted into the cylinder head, which then engages in a correspondingly provided in the cylinder head groove. For this purpose, however, it is necessary that the groove must be milled in accordance with the cylinder head. In addition, in the area in which the rib engages in the milled groove, for reasons of space no insertion bevels can be attached, which facilitate insertion of the valve when installed in the cylinder head. Due to the lack of these chamfers, the assembly of the high-pressure injection valve into the cylinder head is made more difficult and an assembly of a FCA, ie a rail in which several valves are already mounted, then all high-pressure injection valves are mounted with the rail simultaneously in the cylinder head are even almost impossible or at least not suitable for series production, since during assembly all valves must be re-aligned according to their position.

Another solution for positionally fixing a high-pressure injection valve in a cylinder head provides the known use of a hold-down, which then passes the position to the rail and the cylinder head.

However, a transfer of the position from the high-pressure injection valve on the hold-down and then on the rail is only possible if the use of a corresponding hold-down is possible and on the rail a corresponding milling, in this case, a wrench size attached.

In DE 197 35 665 A1 For example, a fuel injection system for direct injection of fuel into a combustion chamber of an internal combustion engine is described, wherein a cylinder head for each fuel injection valve has a opening into the associated combustion chamber receiving bore for receiving the Abspritzabschnitts of the fuel injection valve. The receiving bore is formed there as a stepped bore and has a tapered portion on which a first sealing element sealingly abuts and the Abspritzabschnitt seals against the cylinder head. The fuel injection valve is pivotally mounted on the first designed as an O-ring sealing member so that it is within a predetermined limits by a solid angle α slightly pivoted. In the DE 197 35 665 A1 described arrangement allows pivoting of the fuel injection valve relative to the longitudinal axis within the solid angle range α, wherein by a clamping claw in the entire pivoting range, a sufficient hold-down force is transferable to the fuel injection valve. By tightening the clamping screws Spannspatzen, which are screwed into the cylinder head, the fuel injection valves are rigidly fixed to the cylinder head.

A disadvantage of all known from the prior art solutions for fixing the high-pressure injection valve, however, is that associated with their implementation expensive milling processes.

Advantages of the invention

In contrast, the fuel injection valve according to the invention with the characterizing feature of claim 1 and the fuel injection system according to the invention with the characterizing feature of independent claim 12 have the advantage that a cost-effective solution for fixing the fuel injection valve in a cylinder head is made possible on the one hand sufficient insertion bevels for a problem-free assembly allows the individual high-pressure injection valves and a FCAs and on the other hand ensures accurate positioning of the valve.

According to the invention, a fixing element is provided, which fixes the nozzle body in its position in the first recess, and which is designed in the form of a thickening with a spherical contour. The fixing element has outwardly curved end surfaces and / or plane end surfaces. The cylinder head has a corresponding second recess, in which the fixing element can be inserted, in the form of a slot. The fixing element may preferably z. Example, be provided as a molded pin on the outer periphery of the valve housing, which then engages in the bore or recess in the cylinder head (or in the rail) and thus fixes the fuel injection valve securely in position.

The longitudinal axis of the fixing element is provided substantially coaxially with the longitudinal axis of the fuel injection valve.

Preferably, the convex contour of the fixing element has an undercut above the convex contour, so that a tilting of this Verdrehfixierung in the form of the fixing and thus breaking it is prevented.

In addition, it is particularly advantageous if the Verdrehfixierung in the form of the fixing below the convex contour downwards, d. H. in the direction of the discharge end of the fuel injection valve, tapered to provide a so-called insertion bevel to facilitate the mounting of the high-pressure injection valve.

If the fuel injection valve is not mounted by default with an intermediate sleeve to the rail, which acts as a compensation element, the provision of the slot or the one-sided open slot in the cylinder head is particularly advantageous. For tolerance compensation between the rail cup and the cylinder head bore, the high-pressure injection valve must be slightly inclined. This inclination causes a movement in the Verdrehfixierung. Therefore, it is important that there is sufficient space in the radial direction, so that the radial movement of the valve by the tolerance compensation does not lead to a transverse force (strain) on the Verdrehfixierung or on the fixing.

This can be achieved by the recess or bore in the cylinder head is executed around, but has a significantly larger diameter than the fixing element, which acts as Verdrehfixierung. However, this configuration would have a big game in the middle position and thus a large spray deviation. The execution of the recess or hole as a slot is in contrast particularly advantageous because the necessary assembly clearance between the cylinder head bore and the Verdrehfixierung is independent of the deflection between the rail cup and cylinder head bore. Thus, the assembly play between the cylinder head bore or recess and the Verdrehfixierung be kept constant and particularly small in the form of the fixing. Also, this type of design has a particularly favorable effect on the spray tolerances.

Furthermore, it is advantageous that the fuel injection valve is a multi-hole valve with asymmetrically arranged spray holes and that the sprayed through the injection holes fuel jet is inclined relative to the valve longitudinal axis.

Furthermore, it is advantageous if the bore or recess, in which engages the Verdrehfixierung or at least one fixing element, is designed as a one-sided open slot. This is particularly advantageous in tight spaces, because in this embodiment can be advantageously dispensed with the insertion.

Depending on the production method, the boundary of the recess can be designed, for example, with a radius or as an edge. Contours are also possible that can already be produced with the cast of the cylinder head.

drawing

Fig. 1

einen schematischen Querschnitt durch ein Brenn- stoffeinspritzventil mit Verdrehfixierung;

Fig. 2

eine Seitenansicht des erfindungsgemäßen Fixier- elements;

Fig. 3a - 3d

vier Schnittansichten verschiedener Ausführungsbeispiele von Fixierelementen;

Fig. 4

eine schematische teilweise geschnittene Seitenansicht des erfindungsgemäßen Fixierelements;

Fig. 5a - 5d

jeweilige Seitenansichten eines Abschnitts des Fixierelements mit balliger Kontur;

Fig. 6a - 6c

jeweilige Schnittansichten von unterschiedlich ausgeführten Ausnehmungen im Zylinderkopf mit dazugehörigen Draufsichten auf die Ausnehmungen; und

Fig. 7a, 7b

Schnittansichten eines Ausführungsbeispiels einer Verdrehfixierung in einer runden Zylinderkopfbohrung bzw. Ausnehmung und in einer als Langloch ausgebildeten Ausnehmung.

An embodiment of a fuel injection valve according to the invention and a fuel injection system according to the invention and a fuel injection system according to the prior art is shown in simplified form in the drawing and will be explained in more detail in the following description. Show it:

Fig. 1

a schematic cross section through a fuel injection valve with Verdrehfixierung;

Fig. 2

a side view of the fixing element according to the invention;

Fig. 3a - 3d

four sectional views of various embodiments of fixing elements;

Fig. 4

a schematic partially sectioned side view of the fixing element according to the invention;

Fig. 5a - 5d

respective side views of a portion of the fixing element with spherical contour;

Fig. 6a - 6c

respective sectional views of differently executed recesses in the cylinder head with associated plan views of the recesses; and

Fig. 7a, 7b

Sectional views of an embodiment of a Verdrehfixierung in a round cylinder head bore or recess and in a slot formed as a slot.

Description of the embodiment

Fig. 1 shows a schematic cross section through a fuel injection valve 1. The fuel injection valve 1 in the form of a direct-injection fuel injection valve is installed in a cylinder head 2 of an internal combustion engine.

The fuel injection valve 1 has, at an inlet end 3, a plug connection to a fuel distributor line 4, which is sealed by a seal 5 in the form of an O-ring between the fuel distributor line 4 and a feed nozzle 6 of the fuel injection valve 1. The fuel injection valve 1 has a plug 7 for the electrical contacting for actuating the fuel injection valve 1.

The fuel injection valve 1 has in a first recess 9 or receiving bore of the cylinder head 2 a washer 8, which serves as a compensation element for the fuel injection valve 1 in the receiving bore 9 and manufacturing tolerances of the individual components, such as the nozzle body 11 or a valve housing 13 as well as temperature-related tolerances compensated.

The nozzle body 11 has a sealing ring 12 plugged onto a discharge-side end. The fuel injection system shown here is an example at in which the fuel injection valve 1 is not mounted with an intermediate sleeve to the fuel distributor line 4, but there is only one sealing point between the fuel distributor line 4 and the fuel injection valve 1 in the form of an O-ring 5. Furthermore, this fuel injection valve 1 injects in the extension of a longitudinal axis 16 and is not inclined relative to this. A fixing element 15 extends from a connection region 28 between the plug 7 and the valve housing 13 on the discharge side. The fixing element 15 is received in the cylinder head 2 in a second recess or receiving bore 31 in the form of a blind hole. In this case, a longitudinal axis 29 of the fixing element 15 extends coaxially to the longitudinal axis 16 of the nozzle body 11. At the outer periphery of the fixing element 15, a thickening in the form of four outwardly projecting members 30 is provided, which have a spherical contour. However, the number of outwardly projecting members 30 is variable. Thus, instead of four elements 30, for example, only two or even more than four may be provided. The fixing element 15 is injection-molded, for example, as part of a plastic encapsulation.

Fig. 2 shows a side view of the fixing element 15 according to the invention. The housing 13 is provided with a plastic extrusion, which simultaneously forms the plug 7, on whose outer periphery an outwardly projecting fixing element 15 is formed, which forms a convex contour and as Verdrehfixierung the valve in the cylinder head (not shown) is used. For reinforcement purposes, a rib 17 is also provided along the longitudinal axis 29 on the outer circumference of the fixing element 15, which is molded onto the fixing element 15.

The fixing element 15 or its convex contour and the radially projecting from the fixing element 15 outwardly projecting elements 30, which form the thickening, are formed such that at its upper inflow end, an undercut 19 is provided and in the discharge direction of the fuel injection valve leash insertion 18 in the form of a continuous taper, which the assembly of the fuel injection valve. 1 facilitated. The undercut 19 at the upper end of the convex contour also prevents that after tilting 15 in the cylinder head bore or recess (not shown) tilted.

Fig. 3a to 3d show respective sectional views along the line III - III of Fig. 2 of various embodiments of the Verdrehfixierungen invention or the fixing element 15th

Fig. 3a shows a Verdrehfixierung having four outwardly projecting elements 30, which are provided at 90 ° intervals on the outer circumference of the fixing element 15 and thus form four spherical contours and the thickening of this.

Fig. 3b shows an embodiment which also has four outwardly projecting elements 30, of which, however, each two opposing elements differ in the length with which they protrude from the fixing element 15 radially outward. The outwardly projecting end surfaces 20 of the fixing elements 15 are here in contrast to the in Fig. 3a illustrated embodiment plan, but may also have a curvature, so that a convex contour is provided.

Fig. 3c shows an embodiment in which only two outwardly projecting elements 30 are provided and the remaining outer surfaces of the fixing member 15, where no outwardly projecting members 30 are provided, may be arbitrary.

Finally shows Fig. 3d an embodiment which is similar to that in Fig. 3a is shown, but in addition to the outer periphery of the fixing element 15 a reinforcement in the form of a transverse rib 17 is provided.

In Fig. 4 schematically shows the deviation of the longitudinal axis 29 of the fixing element 15 to the longitudinal axis 20 of the second recess 31 of the cylinder head 2, wherein the two longitudinal axes of a Angle α, which also includes the inclination of the fuel injection valve 1 between the pivot points of the position 23 of the O-ring 5 in the rail cup 21 and the position of the combustion chamber seal 22, for example in the form of a provided around the outer periphery of the nozzle body 11 sealing ring 12 (not shown) features. The Verdrehfixierung of the fuel injection valve 1 in the form of the fixing element 15 with spherical contour engages in the recess 31 a. By virtue of this configuration according to the invention, the rotational fixation in the recess 31 also inclines with a corresponding tolerance compensation. Had the Verdrehfixierung no spherical contour or no undercut above the convex contour, then the Verdrehfixierung or the fixing element 15 could tilt in the recess 31 and break under certain circumstances.

Fig. 5a to 5d show various side views of a portion of the fixing element 15, which has various embodiments of Verdrehungenungen or outwardly projecting members 30 at its outer periphery.

In Fig. 5a are provided on the outer periphery of the fixing element 15 radially outwardly projecting elements 30 which have a spherical contour. At the lower end, the fixing element 15 has an insertion bevel 18.

At the in Fig. 5b In contrast, no insertion bevel 18 is provided, and outwardly projecting elements 30 have a rounded shape.

Fig. 5c FIG. 12 shows an embodiment in which the outwardly projecting elements 30 are flat at their outer end faces 24 and not as in FIG Fig. 5b shown rounded and above and below the outer end surfaces 24 adjacent thereto respective undercuts 19 have.

Fig. 5d shows a further embodiment in which the outwardly projecting elements 30 with a convex, in the direction of the longitudinal axis 29 of the fixing member 15 stretched contour Undercut or have a recess 19 at the upper end.

Fig. 6a to 6c each show sectional views of differently executed second recesses 31 in the cylinder head 2 with associated plan views of the second recesses 31. In Fig. 6a is the second recess 31 or cylinder head bore executed round, in which the Verdrehfixierung of the fixing element 15 (not shown) engages. The second recess 31 must be formed significantly larger than the Verdrehfixierung to allow a radial movement of the fixing member 15 (not shown). The second recess 31 further has an upper hollow truncated cone-shaped portion 25 as an insertion bevel 18 and an adjoining hollow cylindrical portion 26. Fig. 6b shows a second recess 31 into which engages the Verdrehfixierung (not shown) of the fixing element 15, which is designed as a slot. It is particularly advantageous that the necessary assembly clearance between the cylinder head bore or recess 31 is independent of the deflection between the rail cup 21 and cylinder head bore 31. Thus, the mounting clearance between the cylinder head bore 31 and the Verdrehfixierung be kept constant and very small (see Fig. 7b ).

Finally shows Fig. 6c a further embodiment in which the second recess 31 is designed as a one-sided open slot. This is particularly advantageous in confined spaces, since it is possible to dispense with the insertion bevel 18. Depending on the manufacturing method, the boundary of the second recess 31 can be designed with a radius (indicated by the dashed line) or with a step 27 in an edged manner.

Fig. 7a and 7b show the different mounting game, which have formed on the fixing element 15 outwardly projecting elements 30 between a circular recess 31 and a recess formed as a slot 31. As with the distance a shown, there is a large clearance in the center position, which results in a large spray deviation, and which is also not constant when the fuel injection valve 1 is in an inclined position, as indicated by the distance b. As can be seen here, the mounting play in the middle position is greater than in the inclined position. This is not the case when the recess 31 is formed as a slot ( Fig. 7b ). Here the assembly play, which is marked with the distance c, remains constant both in the middle position and in the inclined position.

Claims (17)

1. Fuel injection valve (1), in particular for directly injecting fuel into a combustion chamber of an internal combustion engine, which fuel injection valve (1) has a nozzle body (11) which can be inserted into a recess (9) of a cylinder head (2), a valve housing (13), a plug (7) which adjoins the valve housing (13) and at least one fixing element (15) which fixes the nozzle body (11) in its position in the recess (9), with the fixing element (15) extending at the ejection side from a connecting region (28) between the valve housing (13) and the plug (7),
   characterized
   in that at least one fixing element (15) has a thickened portion on an outer circumference, with the thickened portion being formed by at least one outwardly projecting element (30) with an outwardly curved end surface (24) and/or with a planar end surface (24).
2. Fuel injection valve (1) according to Claim 1,
   characterized
   in that the valve housing (13) is provided with a plastic injection-moulded encapsulation which simultaneously forms the plug (7), with the fixing element (15) being integrally formed on the plastic injection-moulded encapsulation.
3. Fuel injection valve (1) according to Claim 1 or 2,
   characterized
   in that the fixing element (15) has, on its outer circumference, two thickened portions in the form of outwardly projecting elements (30) which are formed on the fixing element (15) at opposite sides.
4. Fuel injection valve (1) according to Claim 2 or 3,
   characterized
   in that four outwardly projecting elements (30) are formed on the outer circumference of the fixing element (15) at intervals of in each case 90°.
5. Fuel injection valve (1) according to one of Claims 2 to 4,
   characterized
   in that the at least one fixing element (15) is formed in the manner of a pin which is injection-moulded on.
6. Fuel injection valve (1) according to one of Claims 1 to 5,
   characterized
   in that at an undercut (19) is provided above the contour of the at least one outwardly projecting element (30) in the direction of the inflow-side end (3) of the fuel injection valve (1).
7. Fuel injection valve (1) according to one of Claims 1 to 6,
   characterized
   in that the contour of the element (30) tapers continuously in the direction of the ejection-side end (14) of the fuel injection valve (1).
8. Fuel injection valve (1) according to one of Claims 2 to 7,
   characterized
   in that a rib (17) is provided on the outer circumference of the fixing element (15), which rib (17) serves as a reinforcement.
9. Fuel injection valve (1) according to Claim 8,
   characterized
   in that the fuel injection valve (1) is sealed off with respect to the rail cup (21) of a fuel distributor line (4) by means of an O-ring (15).
10. Fuel injection valve (1) according to one of Claims 1 to 9,
    characterized
    in that the fuel injection valve (1) is a multi-hole valve with asymmetrically arranged spray holes.
11. Fuel injection valve (1) according to one of Claims 1 to 10,
    characterized
    in that the fuel jet ejected through the spray holes is inclined relative to the valve longitudinal axis (16).
12. Fuel injection system (10) which comprises a fuel injection valve (1) according to one of Claims 1 to 11 and a cylinder head (2) having at least one recess (9) for holding a nozzle body (11) of the fuel injection valve (1),
    characterized
    in that a second recess (31) is provided in the cylinder head (2) for holding the at least one fixing element (15), which recess (31) is formed in the manner of a slot.
13. Fuel injection system (10) according to Claim 12,
    characterized
    in that the slot is formed as a slot which is open at one side.
14. Fuel injection system (10) according to Claim 12 or 13,
    characterized
    in that the second recess (31) is in the shape of a truncated hollow cone in order to provide an insertion bevel (18).
15. Fuel injection system (10) according to one of Claims 12 to 14,
    characterized
    in that the second recess (31) is of hollow cylindrical design in at least one section (26).
16. Fuel injection system (10) according to one of Claims 12 to 15,
    characterized
    in that the fuel injection valve (1) can be connected, at its inflow-side end (3), to a rail cup (21) of a fuel distributor line (4).
17. Fuel injection system (10) according to one of Claims 12 to 16,
    characterized
    in that the at least one fixing element (15) is in engagement with the inner wall of the second recess (31).

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