EP1073837B1 - Fuel injection valve - Google Patents

Description

State of the art

The invention is based on a fuel injection valve according to the preamble of claim 1, claim 13 and of Claim 14.

From DE 197 57 299 A1 is already a Fuel injector known at the downstream a valve seat arranged a fuel injection chamber is. With the valve seat acts to open and close the Valve an axially movable valve needle together, the according to the contour of the valve seat a conical has extending closing section. Upstream of the Valve seat is on the outer circumference of the valve needle obliquely extending swirl duct provided. The swirl channel opens into an annular vortex chamber, which is between the Valve needle and an outer valve housing is formed. From this vortex chamber, the fuel becomes the valve seat guided. From the valve seat following Fuel injection chamber, the fuel flows into one Outlet opening slightly offset from the center the bottom surface of the fuel injection chamber begins and obliquely inclined to the valve longitudinal axis downstream runs.

Advantages of the invention

The fuel injection valve according to the invention with the characterizing features of claim 1 has the advantage that it is in a very simple way and Way is inexpensive to produce. That's it Injector especially at its downstream end simple and yet very accurate mountable. Furthermore is with the fuel injection valve according to the invention a very good atomization and a very precise spray of the fuel e.g. directly into a cylinder one Internal combustion engine reached. It will be a special one even front of sprayed spray achieved. In addition, single strands can be sprayed with large Avoid penetration depth and speed.

In a particularly advantageous manner, the valve seat is in Valve seat element swirling fuel on a supplied extremely short flow path. This very short one Flow path is also guaranteed in that the Outlet already at the end of the Valve seat surface while avoiding any Collecting rooms begins.

The fuel injection valve according to the invention with the Characteristic features of claim 1 has in addition to the advantages already mentioned have the advantage that due the "wiridschiefen" arrangement of the outlet opening swirly, finest atomized fuel sprays all over specifically in particularly desired edge areas, e.g. one Cylinders can be sprayed off without e.g. a wanted one Hohlkegelverteilung must be abandoned.

By the measures listed in the dependent claims are advantageous developments and improvements in the Claim 1 specified fuel injection valve possible.

The disk-shaped swirl element according to claim 1 is very simply structured and therefore easy to form. the Swirl element is the task, a swirl or To generate rotational movement in the fuel. Since it is at the Swirl element is a single component, are in its Handling in the manufacturing process no restrictions too expect.

Ideally, one and the same disc-shaped Twist element for both left and right twist be used. By installing the swirl element either with the front or with the back of the Facing valve seat, this variation is extremely just do it.

Compared to swirl bodies, which grooves on one end or similar spin-producing depressions may in the swirl element with the simplest means an inner Opening area to be created, which extends over the entire axial thickness of the swirl element extends and from a surrounded by the outer peripheral edge area.

To a clear installation position of the swirl element to guarantee and a confusion between right spin and To avoid left twist or a rotation of the To form swirl elements are on the outer circumference of the Swirl elements formed in an advantageous manner installation aids.

By training one of the leadership of the valve needle serving guide element with alternating tooth-shaped protruding areas and intervening Recesses on the outer circumference is a simple way Possibility to create an optimal flow into the Swirl channels of the underlying swirl element to to guarantee.

The modular structure of the elements guide, swirl and Valve seat element and the associated separation of functions has the advantage that the individual components are very flexible can be designed so that by simple variation of an element different sprays to be sprayed (Spray angle, static spray rate) can be generated.

drawing

Embodiments of the invention are in the drawing simplified and in the following Description explained in more detail. 1 shows a Embodiment of a fuel injection valve, FIG 2a is a plan view of a central region of a Valve seat member for a so-called by definition "Right Twist Valve", Figure 2b is a plan view of a middle region of a valve seat member for a after Definition so-called "left-twist valve", Figure 2c a Top view of a middle area of a Valve seat element with two-dimensional offset of Outlet, Figure 3 is a section along the line III-III in Figure 2a, Figure 4 is a section along the line IV-IV in Figure 3 as a first invention Embodiment, Figure 5 shows a fourth embodiment in a representation analogous to Figure 4, Figure 6 a fifth Exemplary embodiment in a representation analogous to FIG. 4, Figure 7 is a simplified symbolic section through a Spray cone, which when spraying fuel from valves according to the embodiments according to FIGS. 5 and 6, Figure 8 shows an embodiment of a disc-shaped Swirl elements in a plan view, Figure 9 a Embodiment of a guide element in one Top view, Figure 10 a second swirl element and Figure 11 a third spin element.

Description of the embodiments

That in the figure 1, for example, as a Embodiment illustrated electromagnetically actuatable valve in the form of an injector for Fuel injection systems of spark-ignited Internal combustion engine has one of a magnetic coil. 1 at least partially surrounded, as the inner pole of a Magnetic circuit serving, tubular, largely hollow cylindrical core 2. The fuel injector is particularly suitable as a high-pressure injection valve for direct injection of fuel into a combustion chamber of a Internal combustion engine. An example stepped Bobbin 3 plastic takes a winding of the Solenoid 1 on and allows in conjunction with the core 2 and an annular, non-magnetic, of the Magnet coil 1 partially surrounded intermediate part 4 with a L-shaped cross section a particularly compact and short Construction of the injection valve in the region of the magnetic coil 1.

In the core 2 is a continuous longitudinal opening. 7 provided, which extends along a valve longitudinal axis. 8 extends. The core 2 of the magnetic circuit also serves as Fuel inlet, wherein the longitudinal opening 7 a Fuel supply channel represents. With the core 2 above the Magnetic coil 1 is firmly connected to an external metal (eg ferritic) housing part 14, which is used as external pole or outer guide element closes the magnetic circuit and the Magnet coil 1 at least in the circumferential direction completely surrounds. In the longitudinal opening 7 of the core 2 is on the inlet side a fuel filter 15 is provided for the Provides filtering out of such fuel components that due to their size in the injector blockages or Could cause damage. The fuel filter 15 is z. B. fixed by pressing in the core 2.

The core 2 forms with the housing part 14, the inlet side End of the fuel injection valve, wherein the upper Housing part 14, for example, in the axial direction just downstream seen on the solenoid coil 1 extends beyond. At the upper housing part 14 closes tightly and firmly a lower tubular housing part 18, the Z. B. an axially movable valve member consisting of an armature 19 and a rod-shaped valve needle 20 and an elongated valve seat carrier 21 encloses or receives. The two housing parts 14 and 18 are z. B. with a circumferential weld firmly connected.

In the embodiment shown in Figure 1 are the lower housing part 18 and the substantially tubular Valve seat carrier 21 by screwing firmly together connected; Welding, soldering or flanging pose as well possible joining methods. The seal between the Housing 18 and the valve seat carrier 21 is z. B. by means of a sealing ring 22. The valve seat carrier 21 has over its entire axial extent an inner Through hole 24, concentric with the Valve longitudinal axis 8 runs.

With its lower end 25, which also at the same time the downstream completion of the entire Represents fuel injector surrounds the Valve seat carrier 21 a in the passage opening 24th fitted disc-shaped valve seat member 26 with a tapering downstream of the truncated cone Valve seat surface 27. In the through hole 24 is the z. B. rod-shaped, a largely circular Cross-section valve needle 20 is arranged, the its downstream end a valve closing portion 28th having. This example, spherical or partial spherical or rounded or conical tapered valve closing portion 28 acts in a known Way with the provided in the valve seat member 26 Valve seat surface 27 together.

Downstream of the valve seat surface 27 is in Valve seat member 26 has an outlet opening 32 for the Fuel introduced. In Figure 1 this is Outlet opening 32 only shown as a blind hole, since it is in the sectional view in Figure 1 about a central Section through the fuel injector is the Outlet opening 32, however, an obliquely inclined extent to the valve longitudinal axis 8 has, as Figure 2a illustrates. The outlet opening 32 in Figure 1 thus runs either in the drawing plane into or out of it.

The actuation of the injection valve takes place in known Way electromagnetic. A piezoelectric actuator as excitable Actuator is also conceivable. Likewise is an actuation via a controlled pressure-loaded piston conceivable. For the axial movement of the valve needle 20 and thus for opening against the spring force in the longitudinal opening 7 of the core 2 arranged return spring 33 and closing of the injection valve is the electromagnetic circuit with the magnetic coil 1, the core 2, the housing parts 14 and 18th and the armature 19. The armature 19 is connected to the Valve closing portion 28 facing away from the end of the valve needle 20 z. B. connected by a weld and the core. 2 aligned. To guide the valve needle 20 during her Axial movement with the armature 19 along the valve longitudinal axis 8 serves on the one hand in the valve seat carrier 21 on the anchor 19 facing the end provided guide opening 34 and on the other hand, an upstream of the valve seat member 26th arranged disc-shaped guide member 35 with a precise guide opening 55. The armature 19 is during surrounded by its axial movement of the intermediate part 4.

Between the guide member 35 and the valve seat member 26th is another disk-shaped element, and one Swirl element 47 is arranged so that all three elements 35, 47 and 26 lie directly on top of each other and in Valve seat carrier 21 Find recording. The three Disc-shaped elements 35, 47 and 26 are for example cohesively firmly connected to each other.

An inserted in the longitudinal opening 7 of the core 2, Pressed or screwed adjusting sleeve 38 is used for Adjustment of spring preload via a centering piece 39 with its upstream side of the adjusting 38th adjacent return spring 33, which is with her opposite side supported on the armature 19. In the anchor 19 are one or more bore-like flow channels 40 provided by the fuel from the longitudinal opening. 7 in the core 2 from over downstream of the flow channels 40th trained connecting channels 41 near the guide opening 34 in the valve seat carrier 21 into the passage opening 24th can get.

The stroke of the valve needle 20 is determined by the mounting position of the Valve seat member 26 predetermined. An end position of Valve needle 20 is in non-energized solenoid 1 by the system of the valve closing portion 28 at the Valve seat surface 27 of the valve seat member 26 set, while the other end position of the valve needle 20 at energized solenoid 1 by the system of the armature 19 at the downstream end face of the core 2 results. The Surfaces of the components in the latter stop area For example, they are chrome plated.

The electrical contacting of the magnetic coil 1 and thus their excitement via contact elements 43, which still outside the bobbin 3 with a Plastic extrusion 44 are provided. The Plastic extrusion 44 may also have more Components (eg housing parts 14 and 18) of the Fuel injection valve extend. From the Plastic extrusion 44 out runs an electrical Connecting cable 45, via which the energization of the solenoid coil 1 he follows. The plastic extrusion 44 protrudes through the in this area interrupted upper housing part 14th

Figure 2a is a plan view of a central region of the Valve seat member 26 for a so-called by definition "Right hand twist valve". Concentric to the valve longitudinal axis 8 is within the middle range located in downstream direction tapered tapered Valve seat surface 27 is formed, with the Valve closing portion 28 of the valve needle 20 to a Seat valve cooperates. To define the location of Outlet opening 32 in the valve seat member 26 is it necessary, two perpendicular axes 49, 50th to declare that in their extension direction respectively spanning imaginary levels, being at the intersection of the two Axles 49, 50 or the two imaginary vertical planes the valve longitudinal axis 8 runs. The first axis 49 is the in Figure 2a horizontally extending axis, and the second Axis 50 is the axis perpendicular in FIG. 2a.

The two axes 49, 50 run in Figure 2a only for better clarification vertically and horizontally. You can but also take any other position rotated 360 °.

Decisive is only their vertical position to each other and their intersection at the valve longitudinal axis 8.

The valve seat surface 27 forms a conical section in Valve seat member 26, which at its downstream end in a bottom portion 51 (Figures 3 and 4) with low Diameter expires. According to the invention lies the deepest Point of the bottom portion 51 not on the valve longitudinal axis 8, but offset on one of the axes 49 or 50, in FIG 2a is an offset z to the axis 50 before. From the deepest Starting from the bottom portion 51, the base extends Outlet opening 32 in the downstream direction. The Entry level 52 of the outlet opening 32 coincides with the Floor area 51 together and so is also with a Offset z to the axis 50 before. However, there is the Center 54 of the entrance plane 52 on the axis 49th lying. The extension of the outlet opening 32 up to its exit plane 53 is parallel to the along the Axis 50 imagined spanned level, but not parallel to the valve longitudinal axis 8. Rather, the runs Outlet opening 32 obliquely inclined to the valve longitudinal axis 8 in downstream direction away from it, being the midpoint 54 'of the exit plane 53 in a projection of the Exit plane 53 into the plane of entry plane 52 also has the same offset z to the axis 50. In Short form allows the geometry of the outlet opening 32nd characterize with eccentric and oblique. The figures 3 and 4 illustrate the described geometry vividly. FIG. 3 shows a section along the Line III-III in Figure 2a, while Figure 4 is a section illustrated along the line IV-IV in Figure 3.

Figures 2a, 3 and 4 illustrate a first Inventive embodiment in which the offset z the central axis 58 of the outlet opening 32, on which the two centers 54, 54 ', the axis 50 is smaller as the radius of the outlet opening 32. Especially the Figures 2a and 4 can be clearly seen that the right Edge of the outlet opening 32 from the central axis 58 from seen over the axis 50 and the valve longitudinal axis. 8 survives. Another constructive feature of Outlet opening 32 is that at a projection the entrance plane 52 and the exit plane 53 in a There is no overlap of the two planes 52, 53, as Figures 2a and 3 can be removed. This is going through a corresponding inclination angle of the central axis 58 to Longitudinal valve axis 8 and the axial length of Outlet opening 32 reached. The outlet opening 32 ends For example, in a convex curved Abspritzbereich 66. With a correspondingly selected swirl element 47 (Figure 11) is in combination with that in Figure 2a Valve seat member 26 shown a so-called "right twist valve" in front.

If the outlet opening 32 is mirrored about the axis 50 in Valve seat member 26 introduced, as Figure 2b as second embodiment shows, then arises Valve seat member 26, which together with a corresponding formed and upstream swirl element 47 (Figure 10) a so-called "left-twist valve" results.

FIG. 2c shows a third exemplary embodiment, which largely corresponds to that shown in Figure 2a. however is the entrance level 52 of the outlet opening 32 now two-dimensionally offset. In addition to the offset z to the axis 50 is in this example, the center 54 of Entry level 52 also by an amount y to the axis 49 before. Other embodiments not shown can be designed such that the center 54 of the Entry level 52 at various points with Center axis 58 designated axis lies. In an advantageous manner Way should the offset y to both sides of the axis 49th however, be small such that the entrance plane 52 e.g. yet has a certain overlap with the axis 49. One puts by turning the two perpendicular to each other Axes 49, 50, the axis 49 such that they turn through the center 54 and the valve longitudinal axis 8 runs, so one notes that the parallelism of central axis 58 and axis 50 is canceled. The two-dimensional offset y, z thus has the effect that the outlet opening 32 now "crooked" runs.

An upstream of the valve seat 27 arranged Swirl element 47 will be described in more detail with reference to FIG. In a particularly advantageous manner, the cone section with the valve seat surface 27 in the valve seat member 26th swirling fuel on an extremely short Flow path supplied. This very short flow path will also guaranteed in that the outlet opening 32 already directly at the end of the valve seat 27 under Avoidance of any collection spaces begins. The Guide element 35 has a dimensionally accurate inner Guide opening 55, through which the valve needle 20th moved through during their axial movement. From the outside Extend forth has the guide member 35 over the circumference distributed a plurality of recesses 56 (see also Figure 9), which a fuel flow at the outer periphery of Guide member 35 along into the swirl element 47 and further towards the valve seat surface 27 guaranteed is.

In Figures 5 and 6 are a fourth and a fifth Embodiment in a sectional view analogous to FIG 4. These examples differ only by the Size of the offset z of the example according to FIGS. 2a, 3 and 4. In the embodiment shown in Figure 5 is the offset z of the central axis 58 of the outlet opening 32, on which the two centers 54, 54 'lie, to Axis 50 is chosen so that it equals the radius of the Outlet opening 32 is. Thus, the right edge of the Outlet opening 32 on the axis 50. In contrast, is the outlet opening 32 in the example of Figure 6 so arranged offset far to the axis 50 that the offset z is greater than the radius of the outlet opening 32nd

With the latter two versions of the Outlet opening 32 are in an advantageous manner Special beam shapes of the sprayed fuel can be achieved. These are especially desirable when certain difficult installation conditions on the internal combustion engine predominate or very oblique, but not rotationally symmetric fuel sprays e.g. in the Gasoline direct injection into the cylinder one Internal combustion engine to be injected. Figure 7 shows an idealized symbolic cut by one Spray cone 67, which when spraying fuel from Valves according to the embodiments of Figures 5 and 6 arises, whereby by a certain shading area 68 a deviation from the rotational symmetry of a cone is present. On the side of the shading area 68, the Spray cone 67 as cut off.

In Figure 8 is a between guide element 35 and Valve seat member 26 embedded swirl element 47 as Single component shown in a plan view. The Swirl element 47 can cost, for example by means of Punching, wire eroding, laser cutting, etching or others known methods of a sheet or by galvanic Deposition are made. In the swirl element 47 is an inner opening portion 90 formed over the entire axial thickness of the swirl element 47 extends. Of the Opening area 90 is from an inner swirl chamber 92, through which the valve closing portion 28 of the valve needle 20 extends through, and a plurality of in the Swirl chamber 92 forming swirl channels 93 formed. The Swirl channels 93 open tangentially into the swirl chamber 92 and Stand with their swirl chamber 92 facing away from the ends 95th not with the outer periphery of the swirl element 47 in FIG Connection. Rather, between the as Inlet pockets formed ends 95 of the swirl channels 93 and the outer circumference of the swirl element 47 a circumferential Edge area 96.

When installed valve needle 20, the swirl chamber 92 is after inside of the valve needle 20 (valve closing portion 28) and outwardly through the wall of the opening portion 90 of the Swirl elements 47 limited. Through the tangential junction the swirl channels 93 in the swirl chamber 92 gets the Fuel imparted an angular momentum in the further Flow is maintained up to the outlet opening 32. Due to the centrifugal force of the fuel is largely hohlkegelförmig hosed. The ends 95 of the swirl channels 93 serve as collection bags, the large area a reservoir for form low-turbulence inflow of the fuel. After Flow deflection occurs slowly and the fuel low turbulence in the actual tangential swirl channels 93rd a, whereby a largely trouble-free swirl generated is.

FIG. 9 is an embodiment of a Guide element 35 can be removed, but in many other Embodiments is also applicable. About his outer circumference has the guide member 35 alternately Recesses 56 and tooth-shaped protruding portions 98th The tooth-shaped regions 98 may be e.g. rounded be formed. The production of the guide element 35 occurs e.g. by punching. In the example of Figure 9 are the Ausnehmungsgrunde 99 inclined, so that the Ausnehmungsgrunde 99 in an advantageous manner perpendicular to the Axes of the swirl channels 93 of the underlying Swirl elements 47 run.

Figures 10 and 11 are intended to indicate that it is always is possible, a fuel injection valve according to the invention with either a left twist or a right twist equip generating swirl element 47. Corresponding then according to the formation of the swirl element 47 the Valve seat elements 26 with differently directed To vary outlet openings 32, as the figures 2a and 2b clarify. Ideally, one and the same thing disk-shaped swirl element 47 both for left-hand twist as can also be used for right-handed spin. Like the figures 10 11 and 11, the swirl element 47 of FIG. 11 is only that mirrored or placed on the back swirl element 47th to figure 10. To a clear position of the To guarantee swirling 47 and a mix-up between right twist and left twist to avoid or one To make anti-rotation of the swirl element 47 are on outer circumference of the swirl element 47, e.g. Installation aids 100 formed. These installation aids 100 may, for example, the Shape of notches, grooves or other depressions, from Flattening or protruding noses or have other surveys.

Claims (4)

1. Fuel injection valve for fuel injection systems of internal combustion engines, in particular for the direct injection of fuel into a combustion chamber of an internal combustion engine, having an excitable actuating element (1, 2; 19), having a valve needle (20) which is movable axially along a valve longitudinal axis (8) and, at its downstream end, has a valve-closing section (28) which interacts with a fixed valve seat (27) in order to open and close the valve, the valve seat (27) being formed on a valve-seat element (26), having an outlet opening (32) which is formed in the valve-seat element (26) downstream of the valve seat (27) and has an inlet plane (52), an outlet plane (53) and a centre axis (58), the centre point (54) of the inlet plane (52) lying offset with respect to the valve longitudinal axis (8) and the centre axis (58) extending at an oblique inclination with respect to the valve longitudinal axis (8), and a first imaginary horizontal axis (49) extending through the centre point (54) of the inlet plane (52) of the outlet opening (32), a second imaginary horizontal axis (50) extending perpendicularly with respect to the first axis (49), and the valve longitudinal axis (8) extending in the point of intersection of the first and second axes (49, 50), and having swirl-generating means (47) arranged upstream of the valve seat (27), characterized in that the outlet opening (32) is arranged in such a way that, if projected into the plane of the inlet plane (52), the centre point (54') of the outlet plane (53) of the outlet opening (32) has a different offset z with respect to the second axis (50) than the centre point (54) of the inlet plane (52) with respect to the second axis (50).
2. Fuel injection valve according to Claim 1, characterized in that the swirl-generating means are configured in the shape of a disc-shaped swirl element (47).
3. Fuel injection valve according to Claim 1 or 2, characterized in that, if the inlet plane (52) and the outlet plane (53) are projected into one plane, there is no overlapping of the two planes (52, 53).
4. Fuel injection valve according to one of Claims 1 to 3, characterized in that the valve seat forms a conical section in the valve-seat element (26) as valve-seat face (27), which conical section tapers at one downstream end into a bottom region (51) which directly forms the inlet plane (52) of the outlet opening (32).

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