Electromagnetically actuatable gas valve, and method for increasing the seal of an electromagnetically actuatable gas valve

Abstract

The invention relates to an electromagnetically actuatable gas valve for metering a gaseous fuel into a suction tract of a motor, in particular a gas or diesel gas motor, comprising a valve seat (1) which is designed as a flat seat and which has multiple annular webs (3) that are arranged in a concentric manner and are connected via at least one radially running web (4) in order to delimit circular or semicircular through-flow openings (2). The electromagnetically actuatable gas valve further comprises a movable valve plate (5) which sealingly interacts with the valve seat (1) and which has multiple annular sealing webs (6) that are arranged in a concentric manner and can be brought into an overlapping arrangement with the circular or semicircular through-flow openings (2) of the valve seat (1). According to the invention, the rigidity of the valve seat (1) and/or the valve plate (5) is substantially constant in the radial direction, the rigidity of the valve seat (1) being greater than the rigidity of the valve plate (5). The invention further relates to a method for increasing the seal of an electromagnetically actuatable gas valve.

Claims

1. An electromagnetically actuatable gas valve for metering a gaseous fuel into a suction tract of an engine, the gas valve comprising a valve seat (1), which is designed as a flat seat and which, to delimit circular or partially circular through-flow openings (2), has a plurality of concentrically arranged annular webs (3), which are connected by at least one radially extending web (4), further comprising a movable valve disk (5), which interacts sealingly with the valve seat (1) and which has a plurality of concentrically arranged annular sealing webs (6), which can be brought into overlap with the circular or partially circular through-flow openings (2) of the valve seat (1), wherein a stiffness of at least one of the valve seat (1) and the valve disk (5) is substantially constant in a radial direction, wherein the stiffness of the valve seat (1) is greater than the stiffness of the valve disk (5), wherein at least one of a web (3) of the valve seat (1) having through-flow openings (2) on both radial sides thereof and a web (6) of the valve disk (5) having openings on both radial sides thereof has a substantially L-shaped cross section, and wherein a first leg (S.sub.1) of the substantially L-shaped cross section forms a seat surface (A.sub.S) or a sealing surface (A.sub.D), and at least one second leg (S.sub.2) reinforces the first leg (S.sub.1).

2. The gas valve as claimed in claim 1, characterized in that a cross-sectional area of a web (3) of the valve seat situated radially on an outside is greater than that of a web (3) situated radially on an inside.

3. The gas valve as claimed in claim 1, characterized in that at least one web (3) of the valve seat (1) having through-flow openings (2) on both radial sides thereof has a substantially L-shaped cross section.

4. The gas valve as claimed in claim 3, characterized in that the second leg (S.sub.2) encloses a right angle with the first leg (S.sub.1).

5. The gas valve as claimed in claim 4, characterized in that the second leg (S.sub.2) is arranged radially on the outside with respect to the radial extent of the first leg (S.sub.1), on the side facing away from the seat surface (A.sub.S) or the sealing surface (A.sub.D).

6. The gas valve as claimed in claim 1, characterized in that the second leg (S.sub.2) is arranged radially on an outside with respect to a radial extent of the first leg (S.sub.1), on a side facing away from the seat surface (A.sub.S) or the sealing surface (A.sub.D).

7. The gas valve as claimed in claim 1, characterized in that the webs (3) of the valve seat (1) are connected by a plurality of radially extending webs (4).

8. The gas valve as claimed in claim 1, characterized in that the sealing webs (6) of the valve disk (5) are connected by at least one radially extending web (7).

9. The gas valve as claimed in claim 1, wherein the stiffness of the valve seat (1) is substantially constant in a radial direction.

10. The gas valve as claimed in claim 1, wherein the stiffness of the valve disk (5) is substantially constant in a radial direction.

11. The gas valve as claimed in claim 1, characterized in that the cross-sectional area of a sealing web (6) of the valve disk situated radially on the outside is greater than that of a sealing web (6) situated radially on the inside.

12. The gas valve as claimed in claim 1, characterized in that at least one sealing web (6) of the valve disk (5) having openings on both radial sides thereof has a substantially L-shaped cross section.

13. The gas valve as claimed in claim 12, characterized in that the second leg (S.sub.2) encloses a right angle with the first leg (S.sub.1).

14. The gas valve as claimed in claim 13, characterized in that the second leg (S.sub.2) is arranged radially on the outside with respect to the radial extent of the first leg (S.sub.1), on the side facing away from the seat surface (A.sub.S) or the sealing surface (A.sub.D).

15. The gas valve as claimed in claim 1, characterized in that the webs (3) of the valve seat (1) are connected by a plurality of radially extending webs (4), which are arranged at equal angular intervals.

16. The gas valve as claimed in claim 1, characterized in that the sealing webs (6) of the valve disk (5) are connected by at least one radially extending web (7), wherein a plurality of radially extending webs (7) is provided.

17. The gas valve as claimed in claim 1, characterized in that the sealing webs (6) of the valve disk (5) are connected by at least one radially extending web (7), wherein a plurality of radially extending webs (7) is provided, which are furthermore arranged at equal angular intervals.

18. An electromagnetically actuatable gas valve for metering a gaseous fuel into a suction tract of an engine, the gas valve comprising a valve seat (1), which is designed as a flat seat and which, to delimit circular or partially circular through-flow openings (2), has a plurality of concentrically arranged annular webs (3), which are connected by at least one radially extending web (4), further comprising a movable valve disk (5), which interacts sealingly with the valve seat (1) and which has a plurality of concentrically arranged annular sealing webs (6), which can be brought into overlap with the circular or partially circular through-flow openings (2) of the valve seat (1), wherein a stiffness of at least one of the valve seat (1) and the valve disk (5) is substantially constant in a radial direction, wherein the stiffness of the valve seat (1) is greater than the stiffness of the valve disk (5), wherein a web (3) of the valve seat (1) having through-flow openings (2) on both radial sides thereof has a substantially L-shaped cross section, and wherein a first leg (S.sub.1) of the substantially L-shaped cross section forms a seat surface (A.sub.S) or a sealing surface (A.sub.D), and at least one second leg (S.sub.2) reinforces the first leg (S.sub.1).

19. The gas valve as claimed in claim 18, wherein a web (6) of the valve disk (5) having openings on both radial sides thereof has a substantially L-shaped cross section, and wherein a first leg (S.sub.1) of the substantially L-shaped cross section of the web (6) of the valve disk forms a seat surface (A.sub.S) or a sealing surface (A.sub.D), and at least one second leg (S.sub.2) of the substantially L-shaped cross section of the web (6) of the valve disk reinforces the first leg (S.sub.1) of the substantially L-shaped cross section of the web (6) of the valve disk.

20. An electromagnetically actuatable gas valve for metering a gaseous fuel into a suction tract of an engine, the gas valve comprising a valve seat (1), which is designed as a flat seat and which, to delimit circular or partially circular through-flow openings (2), has a plurality of concentrically arranged annular webs (3), which are connected by at least one radially extending web (4), further comprising a movable valve disk (5), which interacts sealingly with the valve seat (1) and which has a plurality of concentrically arranged annular sealing webs (6), which can be brought into overlap with the circular or partially circular through-flow openings (2) of the valve seat (1), wherein a stiffness of at least one of the valve seat (1) and the valve disk (5) is substantially constant in a radial direction, wherein the stiffness of the valve seat (1) is greater than the stiffness of the valve disk (5), wherein a web (6) of the valve disk (5) having openings on both radial sides thereof has a substantially L-shaped cross section, and wherein a first leg (S.sub.1) of the substantially L-shaped cross section forms a seat surface (A.sub.S) or a sealing surface (A.sub.D), and at least one second leg (S.sub.2) reinforces the first leg (S.sub.1).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is explained in greater detail below with reference to the attached drawings (FIGS. 1 to 7), which relate to preferred embodiments of the invention. In the drawings:

(2) FIG. 1 shows a longitudinal section through a gas valve according to the invention according to a first preferred embodiment,

(3) FIG. 2 shows a perspective illustration of a valve seat of a known gas valve,

(4) FIG. 3 shows a perspective illustration of a valve disk of a known gas valve,

(5) FIG. 4 shows a perspective sectioned view through the valve seat and the valve disk of a known gas valve,

(6) FIG. 5 shows a perspective sectioned view through the valve seat and the valve disk of a gas valve according to the invention according to a second preferred embodiment,

(7) FIG. 6 shows a perspective sectioned view through the valve seat and the valve disk of a gas valve according to the invention according to a third preferred embodiment, and

(8) FIG. 7 shows a perspective sectioned view through the valve seat and the valve disk of a gas valve according to the invention according to a fourth preferred embodiment.

DETAILED DESCRIPTION

(9) The gas valve illustrated in longitudinal section in FIG. 1 has a valve housing 13, in which a plate-shaped body is inserted to form a valve seat 1. The valve seat 1 is formed by a plurality of concentrically arranged annular webs 3, which are connected by radially extending webs 4 in such a way that partially circular through-flow openings 2 are formed between the webs 3 and 4. In this way, each web 3 forms a sealing seat with a seat surface A.sub.S, which interacts sealingly with a sealing surface A.sub.D of an annular sealing web 6 of a valve disk 5 accommodated movably in the valve housing 13 when the gas valve closes and the plurality of concentrically arranged annular sealing webs 6 of the valve disk 5 are each brought into overlap with a partially circular through-flow opening 2 of the valve seat 1.

(10) A magnet subassembly 9 having a magnet coil 10 for actuating the gas valve is furthermore accommodated in the valve housing 13. Here, the magnet subassembly 9 interacts with an armature 8 capable of a stroke motion, which is operatively connected to the valve disk 5 by an armature pin 11. If the magnet coil 10 of the magnet subassembly 9 is energized, a magnetic field builds up, bringing about a stroke motion of the armature 8 in the direction of the magnet coil 10. Owing to the connection via the armature pin 11, the armature 8 takes the valve disk 5 along at the same time, counter to the spring force of a closing spring 12. The gas valve opens. The maximum stroke of the armature 8 or of the valve disk 5 is predetermined by a stop plate 15 accommodated in the valve housing 13.

(11) If the energization of the magnet coil 10 is ended, the spring force of the closing spring 12 returns the valve disk 5 to its initial position. Owing to the connection via the armature pin 11, the armature 8 is taken along this time and, in this way, is likewise returned to its initial position. The spring force of the closing spring 12 presses the valve disk 5 against the valve seat 1, with the result that the sealing surfaces A.sub.D of the sealing webs 6 of the valve disk 5 rest sealingly on the seat surfaces A.sub.S of the webs 3 of the valve seat 1, and the sealing webs 6 of the valve disk 5 close the through-flow openings 2 of the valve seat 1.

(12) In order to increase the seal in the region of the valve seat 1, the valve disk 5 is less stiff than the valve seat 1. Furthermore, the webs 3 of the valve seat 1 have different cross-sectional areas in order to prevent jumps in stiffness between the individual sealing seats of the valve seat 1.

(13) As can be seen from FIG. 1, the cross-sectional area of the webs 3 of the valve seat 1 increases with the radial distance thereof from a central axis 16 of the gas valve. To this extent, the valve seat 1 of the gas valve in FIG. 1 differs from a conventional valve seat 1 of the kind illustrated by way of example in FIG. 2. This is because the webs 3 in a conventional valve seat 1 each have the same cross-sectional area. Since, with the distance of a web 3 from the central axis 16, the arc length thereof also increases, wherein the arc length corresponds to the length of a web 3 between two radially extending webs 4, the stiffness of a web 3 increases accordingly. The valve seat 1 of a conventional gas valve thus has jumps in stiffness between the individual sealing seats, with the result that, in particular, the webs 3 situated radially on the outside tend to deform, as illustrated by way of example in FIG. 4. In this case, sealing contact between the sealing surfaces A.sub.D and the seat surfaces A.sub.S is not assured. This applies, in particular, because the sealing webs 6 of a conventional valve disk 5 of the kind illustrated by way of example in FIG. 3 also tend to undergo such deformations.

(14) As can be seen from FIG. 3, the sealing webs 6 of the valve disk 5 can also be connected to one another by radially extending webs 7. In the present case, the valve disk 5 shown has three radially extending webs, which are arranged at equal angular intervals. The same applies to the known valve seat 1 shown in FIG. 2. By means of the radially extending webs 4, 7, the stiffness of a web 3 or of a sealing web 6 can be increased since the arc length of the webs 3 or sealing webs 6 can be shortened by increasing the number of webs 4, 7.

(15) The stiffness of a web 3 of the valve seat 1 and/or of a sealing web 6 of the valve disk 5 can accordingly depend on various factors. These factors can be taken into account, in particular, by adapting the cross-sectional area of a web 3 and/or of a sealing web 6 in an appropriate manner.

(16) In the illustrative embodiment in FIG. 1, the webs 3 have an increased cross-sectional area with increasing distance from the central axis 16. The enlargement of the cross-sectional area is brought about by an increase in the overall height of the webs 3 with the respective radial distance thereof from the central axis 16. Here, the height is dimensioned in such a way that the webs 3 have a substantially constant stiffness in the radial direction and jumps in stiffness from sealing seat to sealing seat are avoided.

(17) In order to counteract deformation of the sealing webs 6 of the valve disk 5, they can be designed to correspond to the webs 3 of the valve seat 1. This embodiment is shown by way of example in FIG. 5.

(18) Instead of a rectangular cross section, all the webs or individual webs 3 and/or sealing webs 6 can also have an L-shaped cross section, as shown by way of example in FIGS. 6 and 7. An L-shaped cross section increases torsional stiffness. The L-shaped cross section comprises a first leg S.sub.1 and a second leg S.sub.2, which together enclose a right angle. The second leg S.sub.2 is offset radially outward and is in each case arranged on that side of the first leg S.sub.1 which faces away from the seat surface A.sub.S or the sealing surface A.sub.D. In order to change the cross-sectional area of a web 3 or of a sealing web 6, all that is required is to change the height of the second leg S.sub.2 in an appropriate manner.

(19) The invention is not restricted to the embodiments illustrated. On the contrary, modifications which, in particular, relate to the number and configuration of the webs 3 and/or of the sealing webs 6 and of the radially extending webs 4 and 7 are conceivable. Moreover, different cross sections of the webs 3 and/or of the sealing webs 6 can be combined. The aim of a substantially constant stiffness of the valve seat 1 and/or of the valve disk 5 in the radial direction can be achieved in different ways.

(20) Moreover, it is possible to take further measures to increase the seal of a gas valve according to the invention. For example, a sealing element 14 can be placed between the valve seat 1 and the valve housing 13 to prevent leakage between the valve seat 1 and the valve housing 13 (see FIG. 1).