ELECTROMAGNETICALLY ACTUATABLE METERING VALVE, METHOD FOR OPERATING AN ELECTROMAGNETICALLY ACTUATABLE METERING VALVE

Abstract

The invention relates to an electromagnetically actuatable metering valve for liquids and/or gases, comprising: a valve housing (1); a valve seat element (2) which is connected to the valve housing (1) and in which at least one outlet opening (3) is formed; and a magnetic armature (4) which can move in a stroke-like manner relative to the valve seat element (2) and which is securely connected to a plate- or disc-shaped valve closing element (5) for opening and closing the at least one outlet opening (3) or which forms same; as well as a magnetic core (6) opposite the magnetic armature (4) at a working air gap (14) and at least one spring (7) pretensioning the magnetic armature (4) and the valve closing element (5) in the closing direction. According to the invention, the magnetic armature (4) and the valve closing element (5) are loaded in a targeted asymmetrical manner and/or are shaped in a targeted asymmetrical manner The invention also relates to a method for operating a metering valve for liquids and/or gases.

Claims

1. An electromagnetically actuatable metering valve for liquids and/or gases, the metering valve comprising a valve housing (1), a valve seat element (2) which is connected to the valve housing (1) and in which at least one outlet opening (3) is formed, and a magnetic armature (4) which is configured to move in a stroke-like manner relative to the valve seat element (2) and which is securely connected to a plate- or disc-shaped valve closing element (5) for opening and closing the at least one outlet opening (3), a magnetic core (6) opposite the magnetic armature (4) at a working air gap (14) and at least one spring (7) pretensioning the magnetic armature (4) and the valve closing element (5) in a closing direction, characterized in that the magnetic armature (4) and the valve closing element (5) are loaded in a targeted asymmetrical manner and/or are shaped in a targeted asymmetrical manner.

2. The metering valve as claimed in claim 1, characterized in that the magnetic armature (4) and the valve closing element (5) are asymmetrically loaded in a targeted manner by magnetic and/or spring forces.

3. The metering valve as claimed in claim 1, characterized in that the at least one spring (7) is arranged eccentrically relative to the magnetic armature (4) and the valve closing element (5).

4. The metering valve as claimed in claim 1, characterized in that the magnetic core (6) has a shape deviating from a rotationally symmetrical body and/or has at least one eccentrically arranged recess (8) or elevation (9).

5. The metering valve as claimed in claim 1, characterized in that the magnetic core (6) has an axial offset relative to the magnetic armature (4) and/or the valve closing element (5).

6. The metering valve as claimed in claim 1, characterized in that the magnetic armature (4) and/or the valve closing element (5) has a shape which deviates from a rotationally symmetrical body and/or has or, respectively, have at least one eccentrically arranged recess (8) or elevation (9).

7. The metering valve as claimed in claim 1, characterized in that the magnetic armature (4), the valve closing element (5) and/or the magnetic core (6) has or, respectively, have a peripheral bevel (10).

8. The metering valve as claimed in claim 1, characterized in that the magnetic armature (4) has a pole face (11) which in the closed position of the valve closing element (5) is inclined relative to a pole face (12) formed on the magnetic core (6).

9. A method for operating an electromagnetically actuatable metering valve for liquids and/or gases, wherein a magnetic armature (4) which can move in a stroke-like manner is acted upon, said magnetic armature being securely connected to a plate- or disc-shaped valve closing element (5) for opening and closing at least one outlet opening (3) which is formed in a valve seat element (2), wherein the valve closing element (5) is pretensioned by at least one spring (7) in the closing direction, the method comprising loading the magnetic armature (4) and the valve closing element (5) in a targeted asymmetrical manner such that with a stroke movement the magnetic armature (4) and the valve closing element (5) adopt a defined oblique position deviating from a plane-parallel ideal position.

10. The method as claimed in claim 9, characterized in that the magnetic armature (4) and the valve closing element (5) are loaded in a targeted asymmetrical manner by magnetic and/or spring forces.

11. The metering valve as claimed in claim 1, characterized in that the magnetic armature (4) and the valve closing element (5) are separate elements securely connected to each other.

12. The metering valve as claimed in claim 1, characterized in that the at least one spring (7) is arranged eccentrically relative to the magnetic armature (4) and the valve closing element (5), wherein a plurality of springs (7) are arranged at different angular spacings from one another and/or differ regarding the spring force thereof.

13. The metering valve as claimed in claim 1, characterized in that the magnetic armature (4) and the valve closing element (5) are loaded in a targeted asymmetrical manner.

14. The metering valve as claimed in claim 13, characterized in that the magnetic armature (4) and the valve closing element (5) are shaped in a targeted asymmetrical manner.

15. The metering valve as claimed in claim 1, characterized in that the magnetic armature (4) and the valve closing element (5) are shaped in a targeted asymmetrical manner.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Preferred embodiments of the invention are described in more detail hereinafter with reference to the accompanying drawings, in which:

[0020] FIG. 1 shows a schematic longitudinal section through a metering valve according to the invention according to a first preferred embodiment,

[0021] FIG. 2 shows in part a) a schematic longitudinal section through, and in part b) a plan view of, the magnetic armature of the metering valve of FIG. 1,

[0022] FIG. 3 shows in part a) a schematic longitudinal section through, and in part b) a plan view of, a magnetic armature of a metering valve according to the invention according to a second preferred embodiment,

[0023] FIG. 4 shows in part a) a schematic longitudinal section through, and in part b) a plan view of, a magnetic armature of a metering valve according to the invention according to a third preferred embodiment,

[0024] FIG. 5 shows in part a) a schematic longitudinal section through, and in part b) a plan view of, a magnetic armature and a magnetic core of a metering valve according to the invention according to a fourth preferred embodiment,

[0025] FIG. 6 shows a schematic longitudinal section through a magnetic armature and a magnetic core of a metering valve according to the invention according to a fifth preferred embodiment.

DETAILED DESCRIPTION

[0026] The electromagnetically actuatable metering valve shown in FIG. 1 serves for injecting a gaseous medium, in particular a gaseous fuel, into an intake section of an internal combustion engine. Said metering valve comprises a substantially hollow-cylindrical valve housing 1 into which a plate-shaped valve seat element 2 is inserted. A plurality of outlet openings 3, which run in a circular arc-shaped manner and which are arranged concentrically, are formed in the valve seat element 2, the gaseous medium being injected via said outlet openings into the intake section when the valve is open. In FIG. 1 the metering valve is shown closed, wherein a magnetic coil 13 of a magnetic actuator is de-energized or, respectively, no current is applied thereto. A magnetic armature 4, which can be moved in a stroke-like manner, may be acted upon by means of the magnetic coil 13, said magnetic armature being connected to a plate-shaped valve closing element 5 for closing the outlet openings 3 formed in the valve seat element 2. The stroke of the magnetic armature 4 and of the valve closing element 5 in this case is defined, on the one hand, by the valve seat element 2, and, on the other hand, by an annular stroke stop which surrounds a magnetic core 6 which is opposite the magnetic armature 4 at a working air gap 14. The valve closing element 5 and the magnetic armature 4 are pretensioned in the closing direction, i.e. counter to the valve seat element 2, by a plurality of springs 7.

[0027] To open the metering valve, the magnetic coil 13 is energized so that a magnetic field is formed, the magnetic force thereof acting on the magnetic armature 4 such that said magnetic armature moves in the direction of the magnetic core 6 in order to close the working air gap 14. The entrained valve closing element 5 at the same time lifts away from the valve seat element 2 and opens the outlet openings 3. To close the metering valve, the energization of the magnetic coil 13 is discontinued so that the spring forces of the springs 7 return the magnetic armature 4 and the valve closing element 5 into the initial position thereof.

[0028] When closing the metering valve, the sealing surfaces formed on the valve closing element 5 and on the valve seat element 2 are subjected to a high load and thus a high degree of wear. Over the service life of the metering valve, therefore, it may lead to leakages which reduce the metering accuracy. At the same time, the service life of the metering valve is reduced.

[0029] In order to counteract this, the metering valve of FIG. 1 has a modified magnetic armature 4. This magnetic armature is shown significantly enlarged and simplified in FIGS. 2a and 2b. As may be seen in FIGS. 2a and 2b, the magnetic armature 4 has an eccentrically arranged recess 8 in the form of a bore. As a result, the center of gravity of the magnetic armature 4 is displaced such that this magnetic armature adopts a defined oblique position during a stroke movement. In other words, the stroke movements of the magnetic armature 4 are influenced in a targeted manner by the shaping thereof so that an imperfect undefined movement becomes a movement which, whilst still imperfect, is defined and thus predictable.

[0030] As is shown by way of example in FIGS. 3a and 3b, 4a and 4b, 5a and 5b and 6, a defined preferred position may be achieved by further measures which may be used alternatively or in addition. Moreover, the measures may relate to the magnetic armature 4, the valve closing element 5 and/or the magnetic core 6.

[0031] As shown by way of example in FIGS. 3a and 3b, the magnetic armature 5 (and/or the valve closing element 5 and/or the magnetic core 6) have a peripheral bevel 10.

[0032] As also shown by way of example in FIGS. 4a and 4b, the magnetic armature 4 (or the magnetic core 6) may have an asymmetrical shoulder 15 which results in an eccentrically arranged elevation 9 in the region of a pole face 11 of the magnetic armature 4 (or in the region of a pole face 12 of the magnetic core 6).

[0033] Alternatively or additionally, a targeted axial offset may be implemented so that a longitudinal axis A.sub.1 of the magnetic armature 4 and a longitudinal axis A.sub.2 of the magnetic core 6 do not coincide but are spaced apart from one another at a distance x. This embodiment is shown by way of example in FIGS. 5a and 5b.

[0034] Moreover, an oblique position of the magnetic armature 4 relative to the magnetic core 6 may be already predetermined by non-parallel pole faces 11, 12. In other words, the working air gap 14 is varied across the pole faces 11, 12. This embodiment is shown in FIG. 6.

[0035] Alternatively or additionally, the springs 7 shown in FIG. 1 may be arranged at non-uniform angular spacings so that the pretensioning forces vary over the periphery of the valve closing element 5. Moreover, the use of springs 7 of variable strength is possible.