Gas valve

Abstract

Gas valve for metering a gaseous fuel into an intake manifold of an internal combustion engine, comprising an electromagnet (1) and a movable armature (2) cooperating with the electromagnet (1), which is acted upon by the spring force of at least one closing spring (5) in the direction of a valve seat element (3) in which at least one flow opening (4) is formed, wherein the armature (2) is designed as a disk and has a sealing surface (6) cooperating with the flow opening (4), so that the armature (2) can also be used as a movable sealing element and wherein the armature (2) has at least one recess (7) and / or geometry (8) by which the armature (2) is guided, centered and / or secured against rotation, characterized in that a central recess (7) is provided in the armature (2) in which a positionally fixed dowel pin (9) is received,and the closing spring (5) is a central helical compression spring or a wave spring that surrounds a pot-shaped magnet housing (13) at least partially, or several decentrally arranged helical compression springs are provided as the closing spring (5).

Description

The invention relates to a gas valve for metering a gaseous fuel into an intake manifold of an internal combustion engine, having the features of the preamble of claim 1. State of the art A gas valve of the type described above can be used, in particular, for supplying fuel to gas or gas-diesel engines in passenger cars or commercial vehicles, in rail vehicles and / or on ships. Further possible applications include gas or gas-diesel engines in power generation and / or energy recovery plants. German patent application DE 103 53 011 A1 discloses, by way of example, a gas valve designed in particular for use in a gas engine and serving to regulate a gas flow from an inlet side to an outlet side. The gas valve has a valve housing in which an actuating unit for a magnetic armature is accommodated. The magnetic armature is guided axially displaceably within the valve housing. The magnetic armature is provided with a valve closing element, on the end face of which a sealing element is arranged. This sealing element interacts with a valve seat formed on a seat plate in such a way that a gas flow can be controlled through outlet openings of the seat plate. To reduce wear in the area of ​​the valve seat, the sealing element is made of a plastic material containing a filler. Furthermore, US patent 3,001,757 A discloses a fuel injector in which a disc-shaped armature serves directly as a sealing element. DE 10 2007 050 817 A1 discloses a valve with a tubular armature, US patent 2014 / 0 123 937 A1 discloses a two-fluid injector with an element secured against rotation on its outer circumference, GB patent 1,236 062 A also discloses a valve with a disc-shaped armature, and US patent 5,398,724 A discloses a gas valve with a valve seat element having flow-through openings. The present invention is based on the objective of providing a wear-optimized gas valve that is also particularly compact. To solve the problem, the gas valve with the features of claim 1 is proposed. Advantageous embodiments of the invention can be found in the dependent claims. Disclosure of the invention The proposed gas valve for metering a gaseous fuel into the intake manifold of an internal combustion engine comprises an electromagnet and a movable armature that interacts with the electromagnet. The armature is subjected to the spring force of at least one closing spring in the direction of a valve seat element in which at least one flow opening is formed. According to the invention, the armature is designed as a disk and has a sealing surface that interacts with the flow opening, so that the armature can also be used as a movable sealing element. The armature also has at least one recess and / or geometry by which the armature is guided, centered, and / or secured against rotation. A central recess is provided in the armature in which a positionally fixed dowel pin is received, by which the armature is centered and guided.The closing spring is designed as a central helical spring or a wave spring that surrounds the pot-shaped magnet housing at least partially, or the closing spring is formed by several decentrally arranged helical compression springs. The disc shape of the armature allows for a reduction in the overall height, i.e., the axial dimension, of the gas valve. Since the armature also forms the sealing element, a separate sealing element is unnecessary. This further reduces the overall height. The disc shape of the armature and the elimination of a separate sealing element result in a reduction of the moving mass. This means that the impact energy of the armature when closing the flow opening is lower, and wear in the seating area is reduced. The reduction in moving mass also leads to lower control current consumption. To minimize wear, the anchor is also guided, centered and / or prevented from rotating. The guide is designed to counteract a strong tilting position of the anchor and thus prevent the anchor from becoming wedged. The centering and / or anti-rotation device ensures that the sealing surface formed on the anchor can be brought into contact with at least one flow opening of the valve seat element. Preferably, the central recess in the anchor is designed as an axial bore with a circular cross-section. Such a bore is simple and inexpensive to manufacture. The cross-section of the dowel pin is preferably adapted to the cross-section of the recess in the anchor. The recess and / or the dowel pin provided in the anchor may also have a cross-section that deviates from a circular shape. In this way, in addition to guidance and centering, the anchor can also be prevented from rotating. To fix the position of the dowel pin, it is preferably firmly connected to the valve seat element. Alternatively, the anchor can have at least one circumferential recess and / or geometry and be surrounded by a ring body that is fixed in position. This means that the anchor has an outer contour that deviates from a circular shape. The ring body surrounding the anchor has, at least in some areas, an inner contour adapted to the outer contour of the anchor, so that the anchor is at least guided and centered by the ring body. Preferably, several recesses and / or geometries are provided on the outer circumference of the anchor, which are further preferably arranged at equal angular intervals from each other, i.e. evenly distributed over the outer circumference. To fix the ring body in position, it can be supported on the housing side and / or axially clamped. Preferably, at least one circumferential recess of the anchor is shaped like a circular segment. Such a recess is easy and inexpensive to produce, for example, by grinding or flattening. Alternatively, the recess can also be shaped like a circular arc. Due to the flat disc shape of the anchor, such recesses can be produced cost-effectively by waterjet cutting. The outer circumferential recesses of the anchor can be combined with the formation of outer circumferential geometries, so that both recesses and geometries are formed on the outer circumference of the anchor. The recesses then primarily serve to clear the geometries. Guidance, centering, and / or anti-rotation is then preferably achieved via the geometries. A geometry formed on the outer circumference of the anchor can, for example, have the shape of a tooth. Such a geometry is achieved by incorporating circular segment-shaped recesses into the outer circumference of the anchor, which do not directly adjoin each other. Between these recesses, a tooth-shaped geometry remains. The tooth can have a radially outer surface that guides and centers the anchor. Preferably, at least one geometry on the outer circumference of the anchor simultaneously provides anti-rotation protection. This geometry engages with the ring body. For example, a slot can be formed in the ring body to partially accommodate the geometry. Alternatively, a geometry can be formed on the ring body that engages with the recess of the anchor, through which the anchor geometry is exposed. Furthermore, it is proposed that the at least one flow opening of the valve seat element be radial or arc-shaped. Preferably, several radially or arc-shaped flow openings are formed in the valve seat element to enable high mass flow rates. If the at least one flow opening of the valve seat element is radial, the angular position of the armature relative to the valve seat element can be crucial for the reliable closure of the gas valve. This is not the case if the flow opening of the valve element is arc-shaped. In this case, it is essential that the armature is centered relative to the valve seat element. A dowel pin provided for centering is therefore preferably fixed to the valve seat element. Advantageously, the armature has / have at least one flow opening and / or pressure equalization opening, which is / are arranged offset from the at least one flow opening of the valve seat element. The gas is supplied to the flow opening in the valve seat element via the at least one flow opening provided in the armature. To ensure a uniform flow, several flow openings are preferably provided in the armature. Pressure equalization is achieved via the at least one pressure equalization opening during an opening or closing movement of the armature. The offset arrangement of the at least one flow opening or pressure equalization opening of the armature relative to the flow opening of the valve seat element ensures that the gas valve closes tightly. Another advantage is that the moving mass is further reduced by the at least one flow opening and / or pressure equalization opening in the armature. Furthermore, it is proposed that the electromagnet be housed in a pot-shaped magnet casing, which preferably has at least one inlet opening. The inlet opening is intended to ensure a uniform distribution of the incoming gas. For this reason, several inlet openings are preferably provided, evenly distributed around the circumference of the magnet casing. Preferably, the at least one inlet opening is designed as a cutout in an end face of the magnet casing facing the armature. Such an inlet opening is simple and inexpensive to manufacture. The closing spring that loads the anchor in the closing direction can be a helical compression spring that is centrally located and thus loads the anchor in the middle. The closing spring acts radially on the outer side of the armature, preferably in the area of ​​the sealing surface. This ensures a tight closure of the gas valve. If several decentrally arranged helical compression springs are provided as closing springs, they are preferably arranged at the same angular distance from each other to ensure a uniform distribution of the closing force. Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a schematic longitudinal section through a first preferred embodiment of a gas valve according to the invention, Fig. 2 a perspective view of the armature of the gas valve of Fig. 1, Fig. 3 a perspective view of a modified armature for a gas valve according to the invention, Fig. 4a a perspective view of an armature in combination with a valve seat element, Fig. 4b a top view of the armature of Fig. 4a, Fig. 4c a detail of Fig. 4b in an enlarged view, Fig. 5 a schematic longitudinal section through a second preferred embodiment of a gas valve according to the invention, Fig. 6 a schematic longitudinal section through a third preferred embodiment of a gas valve according to the invention, Fig.Fig. 7 shows a schematic longitudinal section through a fourth preferred embodiment of a gas valve according to the invention, and Fig. 8 shows a schematic longitudinal section through a fifth preferred embodiment of a gas valve according to the invention. Detailed description of the drawings The gas valve schematically depicted in Fig. 1 comprises an electromagnet 1 for acting on an armature 2, which is designed as a flat disk. The armature 2 has a sealing surface 6 that can be brought into contact with flow openings 4, which are formed in a plate-shaped valve seat element 3, to close the gas valve. The armature 2 thus also forms a sealing element. Furthermore, the armature 2 is subjected to the spring force of a closing spring 5 in the direction of the valve seat element 3. In this case, the closing spring is designed as a Smalley wave spring. The Smalley wave spring is arranged radially outwards with respect to a pot-shaped magnet housing 13, in which the electromagnet 1 is received. To ensure optimal gas flow, the magnet housing 13 has end faces with cutouts that form inlet openings 15.The armature 2 also includes flow openings 11 and pressure equalization openings 12, which also ensure a uniform distribution of the gas (see Fig. 2). The gas valve is supplied with flow radially via radial bores 14 formed on the housing side. To open the gas valve, the electromagnet 1 is energized. A magnetic field builds up, the magnetic force of which moves the armature 2 towards the electromagnet 1. The armature 2 then lifts off the valve seat element 3 and exposes the flow openings 4 formed in the valve seat element 3. To close the valve, the energization of the electromagnet 1 is stopped, the magnetic field dissipates, and the armature 2 is returned to its initial position by the spring force of the closing spring 5, whereby the sealing surface 6 formed on the armature closes the flow openings 4 formed in the valve seat element 3. To guide and center the disc-shaped armature 2 of the gas valve in Fig. 1, a central recess 7 is provided in the armature 2, in which a dowel pin 9 is received and which is fixed in position by the valve seat element 3. The armature 2 is guided and centered by the dowel pin 9 received in the recess 7 (see also Fig. 2). An alternative embodiment of an anchor 2 is shown in Fig. 3. Here, guidance and centering are achieved by means of geometries 8 formed on the outer circumference, which are evenly distributed around the outer circumference of the anchor 2. To form the geometries 8, three arc-shaped recesses 18 were made in the outer circumference of the anchor 2, so that three tooth-like geometries 8 remain between them. Guidance and centering are achieved by means of the radially outer surfaces of the geometries 8. In the embodiments shown in Figs. 2 and 3, the flow openings 11 of the armature 2 are each shaped like circular arcs. This is particularly the case when the flow openings 4 of the valve seat element 3 also have a circular arc shape. However, this is not strictly necessary. Figures 4a to 4c show an alternative embodiment of an anchor 2 serving as a sealing element and a valve seat element 3. Here, the flow openings 4 and 11 are each radially oriented. To ensure a permanently tight closure of the gas valve, the anchor 2 must be secured against rotation relative to the valve seat element 3. In order to achieve anti-rotation protection in addition to guiding and centering the anchor 2, the recess 7 and / or the dowel pin 9 in the embodiment of Fig. 1 can have a cross-sectional shape that deviates from the circular shape. If the anchor 2 has at least one geometry 8, this can be brought into engagement with a recess (not shown), which is preferably formed on a ring body 10 that surrounds the anchor 2. Further preferred embodiments of the invention are shown in Figs. 5, 6, 7 to 8. The gas valve shown in Fig. 5 is essentially the same as that in Fig. 1, with the difference that a plate 16 for receiving the dowel pin 9 is inserted into the valve seat element 3. In addition, the magnet housing 13 is modified. If the Smalley wave spring of the gas valve in Fig. 5, which serves as the closing spring 5, is replaced by several decentrally arranged helical compression springs, the embodiment shown in Fig. 7 is obtained. A ring 17 is provided to support the helical compression springs, which in turn is supported on the magnet housing 13. Figure 6 shows an embodiment of a gas valve according to the invention, which, instead of a central recess 7 provided in the armature 2, has several geometries 8 formed on the outer circumference of the armature 2 for guiding and centering the armature 2. The armature 2 rests radially against an annular body 10, which surrounds the armature 2, via these geometries 8. In the embodiment of Figure 6, the closing spring 5 is a Smalley wave spring. Replacing the Smalley wave spring of the gas valve in Fig. 6 with several decentrally arranged helical compression springs results in the embodiment shown in Fig. 8. A ring 17 is again provided to support the helical compression springs, which is itself supported on the magnet housing 13.

Claims

Gas valve for metering a gaseous fuel into an intake manifold of an internal combustion engine, comprising an electromagnet (1) and a movable armature (2) cooperating with the electromagnet (1), which is acted upon by the spring force of at least one closing spring (5) in the direction of a valve seat element (3) in which at least one flow opening (4) is formed, wherein the armature (2) is designed as a disk and has a sealing surface (6) cooperating with the flow opening (4), so that the armature (2) can also be used as a movable sealing element and wherein the armature (2) has at least one recess (7) and / or geometry (8) by which the armature (2) is guided, centered and / or secured against rotation, characterized in that a central recess (7) is provided in the armature (2) in which a positionally fixed dowel pin (9) is received,and the closing spring (5) is a central helical compression spring or a wave spring that surrounds a pot-shaped magnet housing (13) at least partially, or several decentrally arranged helical compression springs are provided as the closing spring (5). Gas valve according to claim 1, characterized in that the recess (7) and / or the dowel pin (9) has or have a cross-section that deviates from the circular shape. Gas valve according to one of the preceding claims, characterized in that the valve seat element (3) has at least one radially or arcuately extending flow opening (4), wherein preferably several radially or arcuately extending flow openings (4) are formed in the valve seat element (3). Gas valve according to one of the preceding claims, characterized in that at least one flow opening (11) and / or pressure equalization opening (12) is / are formed in the armature (2), which is / are arranged offset from the at least one flow opening (4) of the valve seat element (3). Gas valve according to one of the preceding claims, characterized in that the electromagnet (1) is received in the pot-shaped magnet housing (13), which preferably has at least one inlet opening (15).

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