Gas injector with robust needle guide

Abstract

The present invention relates to a gas injector for injecting a gaseous fuel, comprising; a magnetic actuator (2) having an armature (20), an inner pole (21) and a coil (22); a closing element (3) having a valve needle (30), wherein the closing element (3) opens and closes a gas path (14) at a sealing seat (11), wherein the armature (20) is connected to the closing element (3); a closed lubricant chamber (4) which is filled with a lubricant and in which the armature (20) is arranged, wherein the lubricant ensures lubrication of the armature (20); a flexible sealing element (51) which seals the lubricant chamber (4) with respect to the gas path (14); a return element (10) which is arranged in the lubricant chamber (4) and which returns the closing element (3) to a closed starting position; and a first needle guide (31), a second needle guide (32) and a third needle guide (33) which are designed to guide the valve needle (30), wherein the first needle guide (31) and the second needle guide (32) are arranged in the gas path (14) and the third needle guide (33) is arranged in the lubricant chamber (4).

Description

[0001] Description

[0002] title

[0003] Gas injector with robust needle guide

[0004] State of the art

[0005] The present invention relates to a gas injector for injecting a gaseous fuel, in particular hydrogen or natural gas or the like, with very robust and durable guide properties for guiding a long valve needle of a closing element of the gas injector. The gas injector is designed in particular for direct injection into the combustion chamber of an internal combustion engine.

[0006] Gas injectors are known in various designs from the prior art. One problem with gas injectors is that, due to the gaseous medium being injected, lubrication by the medium is not possible, as is the case with fuel injectors that inject gasoline or diesel, for example. This results in excessive wear during operation compared to fuel injectors for liquid fuels, particularly in the area where a valve needle guides. Furthermore, due to the increasing miniaturization of internal combustion engines, a compact design is often necessary.

[0007] Disclosure of the invention

[0008] The gas injector according to the invention for injecting a gaseous fuel with the features of claim 1, however, has the advantage that the gas injector has particularly good guiding properties for a valve needle of a closing element of the gas injector. In particular, tilting moments, which can be exerted on the valve needle, for example, by a return element, can be reliably absorbed and do not lead to an inclined position of the valve needle on the sealing seat. The gas injector is therefore sealed at the sealing seat in the closed state in all operating situations. This is achieved according to the invention in that the gas injector comprises a magnetic actuator with an armature, an inner pole and a coil. Furthermore, the gas injector comprises a closing element with a valve needle, which opens and closes a gas path for the gaseous fuel at a sealing seat. The armature is connected to the closing element.Furthermore, a sealed lubricant chamber is provided, which is filled with lubricant and in which the movable armature is arranged. The lubricant ensures lubrication of the armature so that no wear occurs on the armature during operation. The lubricant chamber comprises at least one flexible sealing element, in particular a bellows, which seals the lubricant chamber from the gas path and thus ensures the axial mobility of the closing element. Furthermore, the gas injector comprises a return element, in particular a closing spring in the form of a cylindrical spring, wherein the return element returns the closing element to a closed initial position. Furthermore, the gas injector comprises a first, second and third needle guide, which guide the valve needle during the opening and closing processes.The first and second needle guides are arranged in the gas path, and the third needle guide is arranged in the lubricant chamber. The return element is also arranged in the lubricant chamber. Thus, movements of the return element and the third needle guide, which are lubricated by the lubricant in the lubricant chamber, generate no wear, or at most minimal, negligible wear. The first and second needle guides, which are arranged in the gas path, are thus located outside the lubricant chamber. If a tilting moment is exerted on the valve needle by the return element during operation, this tilting moment can be safely absorbed by the two first and second needle guides arranged in the gas path. This prevents any bending of the valve needle, which could be caused by the tilting moment that may occur, from the two first and second needle guides.This ensures that the sealing seat remains closed in all operating situations, preventing the valve needle from tilting at the sealing seat and thus failing to close properly. The valve needle is thus securely guided by a double guide outside the lubricant chamber and a guide inside the lubricant chamber.

[0009] The subclaims disclose preferred developments of the invention. Preferably, a first distance A1 between the first and second needle guides in the axial direction XX of the gas injector is smaller than a second distance A2 between the second and third needle guides in the axial direction XX. This provides particularly good absorption of any tilting moments that may occur by the first and second needle guides. The second distance A2 is preferably at least twice as large, more preferably at least three times as large, as the first distance A1.

[0010] Further preferably, the first and / or second and / or third needle guide each have an annular guide region which is connected to the valve needle of the closing element via webs, such that openings for fluid passage are present between the webs. This is particularly advantageous on the first and second needle guides, which are arranged in the gas guide region of the gas injector, in order to allow the largest possible quantities of gas to flow through the first and second guide regions when the gas injector is open. The annular guide region is preferably closed along its entire circumference. In order to keep friction during the opening and closing process of the closing element as low as possible, the width of the annular guide region is selected to be as small as possible. Particularly preferably, three webs are provided which connect the valve needle to the annular guide region.The webs are preferably arranged at equal distances along the circumference.

[0011] According to a particularly preferred embodiment of the invention, the webs between the valve needle and the annular guide regions are arranged at an acute angle to the annular guide region. This makes it possible to increase the flow cross-section in the region of the guides, which is particularly advantageous for the first and second needle guides, which are located in the gas guide region. The webs are preferably arranged downstream of the guide region in the flow direction through the openings. Alternatively, the webs between the valve needle and the annular guide region of the needle guides are arranged at a right angle to the valve needle. According to a further alternative embodiment of the invention, the first and / or second and / or third needle guides are designed exclusively as webs which run radially outwards from the valve needle and have guide regions at their free ends.Further alternatively, the first and / or second and / or third needle guide are designed as guide ribs which have a greater extension in the axial direction than in the radial direction.

[0012] According to a particularly preferred embodiment of the invention, a plate to which the flexible sealing element is fixed is also arranged on the valve needle. This allows for a simple connection between the closing element and the flexible sealing element, which seals the lubricant chamber.

[0013] Preferably, the first and second needle guides are guided on the same component. This component is preferably a cylindrical valve body, on which the sealing seat is also located. This makes it possible to manufacture the guide surfaces for the first and second needle guides in a single setup, which offers significant manufacturing advantages and further reduces manufacturing costs.

[0014] To further reduce the number of components, the third needle guide is preferably also designed to support the return element, which is arranged in the lubricant chamber. The third needle guide can preferably be designed as a spring plate with openings for the lubricant during the opening and closing process of the closing element.

[0015] More preferably, a third distance A3 between the first needle guide and the sealing seat is smaller than the first distance A1 between the first and second needle guides. The third distance A3 is preferably smaller than half of the first distance A1 and particularly preferably smaller than a third of the first distance A1. The closing element can be formed as one piece with the two lower needle guides and the disk for receiving the elastic element or as multiple pieces. For example, several disks, disks for the guide and the disk for receiving the elastic element, can be welded to a pin. The pin can also form one part with the seat plate to which the disks for the valve needle guides and for receiving the elastic element are welded.

[0016] The flexible sealing element is preferably a metal bellows. On the one hand, the metal bellows provides excellent mobility to enable the axial movements of the closing element, and on the other hand, it allows the metal bellows to be positioned as close as possible to the hot combustion chamber of the internal combustion engine. This allows the axial length of the gas injector to be further reduced. Alternatively, the flexible sealing element can be a plastic bellows, a diaphragm, or a rubber element.

[0017] The gas injector further preferably has a conical seat or a ball-and-conical seat. Preferably, the closing element comprises a sealing disc at an end facing the combustion chamber, which opens one or more through openings at a sealing seat. The gas injector is preferably designed as an outward-opening injector. This makes it possible to provide a sealing seat that lies in a plane perpendicular to the longitudinal direction of the gas injector.

[0018] Furthermore, the gas injector preferably comprises a braking device arranged in the lubricant chamber, which is configured to brake the closing element during a return process of the gas injector from the open to the closed state. The braking device comprises a braking bolt, a damping chamber fluidly connected to the lubricant chamber, and an elastic braking element, in particular a spring. The braking bolt and the elastic braking element are operatively connected to the closing element and / or the armature during the return process, wherein the braking bolt is further configured to displace lubricant from the damping chamber during the return process in order to dampen a return of the braking bolt.Since part of the braking process is provided by hydraulic adhesion between the brake bolt and a stop component against which the brake bolt rests when the gas injector is open, the provision of the damping chamber can prevent vapor bubble formation of the liquid lubricant when overcoming the hydraulic adhesion, so that, in particular, wear due to cavitation can be prevented.

[0019] The braking process is further assisted by the acceleration of the additional masses provided by the braking device. Furthermore, further deceleration is achieved by the displacement of the lubricant between the armature and the brake bolt. Friction between guide elements or similar elements and the brake bolt can also further reduce the return speed of the locking element. All of this reduces the impact force of the armature at the stop, thus further extending the service life of the armature.

[0020] Further preferably, the brake bolt comprises, in particular, a main body with a contact surface, which is arranged on a side of the main body of the brake bolt facing the locking element and can be brought into operative connection with the locking element and serves as a stop surface. The main body is preferably cylindrical. Further preferably, an annular flange is arranged on the side of the main body facing the locking element. The annular flange preferably serves as a stop surface.

[0021] According to a further preferred embodiment of the invention, the elastic braking element of the braking device is arranged in the damping chamber. This allows for a particularly compact design. The elastic braking element is preferably a compression spring, in particular a cylindrical spring.

[0022] Further preferably, the damping chamber is in fluid communication with the lubricant chamber via a guide play of the brake bolt.

[0023] The gas injector preferably further comprises a throttle that connects the damping chamber to the lubricant chamber. The throttle ensures that the damping process can proceed in a defined manner, since the lubricant is then transferred from the damping chamber to the lubricant chamber via the throttle. The throttle is preferably a small connecting bore between the damping chamber and the lubricant chamber. The damping behavior of the braking device can be adjusted by selecting the geometric dimensions of the connecting bore, for example, the diameter and / or length of the bore.

[0024] The gas injector further preferably comprises an anchor bolt that rests against the closing element, the anchor bolt being connected to the armature. An end of the anchor bolt facing away from a sealing seat of the gas injector is configured to contact the brake bolt when the gas injector is closed.

[0025] Preferably, an oil, especially a synthetic oil, is used as the lubricant. Alternatively, a liquid fuel, especially diesel or gasoline, is used. Further alternatively, a grease is used as the lubricant.

[0026] Short description of the drawing

[0027] An embodiment of the invention will be described in detail below with reference to the accompanying drawings. In the drawing:

[0028] Figure 1 is a schematic sectional view of a gas injector according to a first embodiment of the invention,

[0029] Figure 2 is a schematic partial sectional view of the gas injector of

[0030] Figure 1 ,

[0031] Figure 3 is a schematic perspective view of the first and second needle guides of the gas injector of Figure 1,

[0032] Figure 4 is a schematic perspective view of a first and second needle guide of a gas injector according to a second embodiment of the invention,

[0033] Figure 5 is a schematic, perspective view of a first and second needle guide of a gas injector according to a third embodiment of the invention, and Figure 6 is a schematic, perspective view of a first and second needle guide of a gas injector according to a fourth embodiment of the invention.

[0034] Preferred embodiments of the invention

[0035] A gas injector 1 according to a first preferred embodiment of the invention will be described in detail below with reference to Figures 1 to 3.

[0036] As can be seen from Figure 1, the gas injector 1 for introducing a gaseous fuel comprises a magnetic actuator 2, which moves an outwardly opening closure element 3 from a closed state to an open state. Figure 1 shows the closed state of the gas injector.

[0037] The magnetic actuator 2 comprises an armature 20, which is connected to the locking element 3 by means of an armature bolt 24. Furthermore, the magnetic actuator 2 comprises an inner pole 21, a coil 22, and a magnet housing 23, which ensures a magnetic return path of the magnetic actuator.

[0038] The gas injector 1 further comprises a main body 7 with a gas inlet 70 through which the gaseous fuel is supplied. A valve housing 8, in which the magnetic actuator 2 is arranged, is fixed to the main body 7. Adjoining the valve housing 8 is a housing sleeve 19, at the free end of which a sealing seat 11 is provided on a valve seat component 93, at which the closing element 3 opens and closes a passage for the gaseous fuel.

[0039] Figure 1 schematically shows an electrical connection 13 which is guided through the main body 7 and the magnet housing 8 to the magnet actuator 2.

[0040] Reference numeral 10 denotes a return element for the closing element 3, in order to return it to the closed state shown in Figure 1 after an opening process. Figure 1 also shows a gas flow as a gas path 14 through the gas injector 1. The gas flow begins at the gas inlet 70 and is then redirected into an annular space 80 between the valve housing 8 and the main body 7. The gas flow 14 continues past an outer region of the magnetic actuator 2 through a filter 15 up to the sealing seat 11. Corresponding openings are provided in the respective components, not all of which are shown in Figure 1.

[0041] When the gas injector 1 is opened, the gaseous fuel flows past the outer circumference of the magnetic actuator 2 and the opened sealing seat 11 into a combustion chamber 100 of an internal combustion engine, which is indicated in Figure 1 by the arrows A.

[0042] The closing element 3 comprises a valve needle 30 with a seat plate 30a, which is arranged at the end of the closing element facing the combustion chamber. The sealing seat 11 is formed between the seat plate 30a and the valve seat component 93, which is a cylindrical tube.

[0043] The closing element 3 further comprises a first needle guide 31, a second needle guide 32 and a third needle guide 33. The three needle guides 31, 32, 33 are formed in one piece or in multiple pieces with the valve needle 30.

[0044] The closing element 3 further comprises a plate 34 which is arranged in the axial direction XX between the second needle guide 32 and the third needle guide 33.

[0045] Furthermore, the gas injector 1 comprises a closed lubricant chamber 4. The closed lubricant chamber 4 is completely or partially filled with a liquid lubricant, e.g. oil.

[0046] As can be seen from Figure 1, the lubricant chamber 4 is defined by a first flexible sealing element 51, the inner pole 21, the magnet housing 23, a guide body 18, and a second flexible sealing element 52. The first and second flexible sealing elements 51, 52 are each designed as bellows. It should be noted that, instead of a bellows, the flexible sealing elements 51, 52 can also be, for example, a membrane or a hose or the like.

[0047] As can be further seen from Figure 1, the second flexible sealing element 52 is fixed to a storage spring plate 41, for example, by means of a welded connection. Furthermore, the gas injector 1 comprises a storage compression spring 40, which is supported on the main body 7 and preloads the second flexible sealing element 52 via the storage spring plate 41. Connecting bores 18a are provided in the guide body 18, so that the lubricant located in the lubricant chamber 4 is also located in the area within the second flexible sealing element 52.

[0048] The first flexible sealing element 51 is fixed directly to the closing element 3 at the plate 34 and is connected at the other end to a guide sleeve 9. The third needle guide 33 is guided within the guide sleeve 9.

[0049] Thus, the lubricant chamber 4 has two flexible sealing elements 51, 52 and the accumulator pressure spring 40. The accumulator pressure spring 40 exerts a certain preload, for example 1 x 10 5 Pa, onto the lubricant located in the lubricant chamber 4. If, during an opening process, the lubricant is displaced by the stroke of the closing element 3 or by thermal expansion or cooling of the lubricant, any overpressure / underpressure that may arise inside the lubricant chamber 4 can be compensated by deflection of the second flexible sealing element 52 in conjunction with a contraction of the accumulator compression spring 40. Thus, the flexible sealing element 51 cannot exert any unwanted force acting on the closing element 3 via the bellows effective surface.

[0050] The armature bolt 24 with the armature 20 fixed to it is also arranged in the enclosed lubricant chamber 4. Since the lubricant chamber 4 is filled with a lubricant, for example an oil with a viscosity of gasoline or diesel, or a grease or the like, the armature 20 is continuously lubricated. This compensates for the problem that occurs in the prior art with gaseous fuels, namely a lack of lubrication of the moving parts. The third needle guide 33 is also arranged in the lubricant chamber 4. As can be seen in particular from Figure 2, the third needle guide 33 is guided inside the guide sleeve 9. Also arranged inside the guide sleeve 9 is the return element 10, which is supported on a shoulder 9a of the guide sleeve 9 and the third needle guide 33.The third needle guide 33 thus has two functions: guiding the valve needle 30 and supporting the return element 10. Corresponding openings 33a are provided in the third needle guide 33 so that the lubricant located in the lubricant chamber 4 can pass through these openings.

[0051] The guide sleeve 9 is connected to the first flexible sealing element 51, for example by means of a welded connection.

[0052] Since the third needle guide 33 is arranged in the lubricant chamber 4, sufficient lubrication is available in all operating situations of the gas injector, so that no wear occurs on the third needle guide during operation.

[0053] The first needle guide 31 and the second needle guide 32, however, are arranged in the gas path 14. As can be seen in detail in Figure 3, the first needle guide 31 and the second needle guide 32 are constructed identically. The first needle guide 31 comprises an annular guide region 31a, which is connected to the valve needle 30 via three webs 31b. Openings 33c are formed between the webs for fluid passage. The webs are designed to be as thin as possible in order to provide the largest possible passage cross-section for the medium to be injected.

[0054] The second needle guide 32 is designed in the same way as the first needle guide 31 with an annular guide area 32a, three webs 32b and corresponding openings 32c formed between the webs.

[0055] The annular guide regions 31a and 32a on the first and second needle guides thus enable particularly secure and precise guidance of the closing element 3. During operation, tilting moments can be exerted on the closing element by the return element 10 and, if appropriate, also by the first flexible sealing element 51 designed as a bellows. However, these can be absorbed by the first and second needle guides, so that the valve needle 30, which is designed with the smallest possible cross-section and has a certain overall length in the axial direction XX, can be yielding and bending due to such tilting moments. Due to the flexibility of the valve needle, only minimal transverse forces act on the needle guides when tilting moments arise from the closing element or the elastic element.As can be seen from Figure 1, a first distance A1 between the first needle guide 31 and the second needle guide 32 is smaller than a second distance A2 between the second needle guide and the third needle guide 33.

[0056] This allows the gas injector to be designed very slim and with a certain overall length, without undesirable transverse forces being exerted on the valve needle during operation due to tilting moments of the return element 10 or the first flexible sealing element 51. This allows the gas injector to always seal in all operating situations and to be safely returned to the closed, sealing state even after an opening process. Wear on the valve needle guides is thus also negligible.

[0057] Furthermore, a third distance A3 between the first needle guide 31 and the sealing seat 11 is smaller than the first distance A1 between the first and second needle guides 31, 32. This additionally supports the closing process so that the sealing seat can always be closed correctly.

[0058] A braking device 6 is also arranged in the enclosed lubricant chamber 4. The braking device 6 comprises a brake bolt 60, a brake spring 61, and a damping chamber 62. The damping chamber 62 is in fluid communication with the lubricant chamber 4.

[0059] The brake bolt 60 and the elastic brake element 61 are operatively connected to the closing element 3 during a return process of the gas injector to the closed starting position. During the return process, lubricant is displaced from the damping chamber 62 into the lubricant chamber 4 to achieve additional damping during the return of the brake bolt 60 to the closed state of the gas injector (Figure 1). The brake bolt 60 is guided in the guide body 18.

[0060] As can be further seen from Figure 1, the damping chamber 62 is formed directly on the brake bolt 60, on a side of the brake bolt 60 facing away from the sealing seat 11. The damping chamber 62 is connected via a throttle 63, which is a small bore, to the connecting bores 18a and thus to the main area of ​​the lubricant chamber 4. The brake spring 61 is arranged in a spring chamber 67.

[0061] The brake bolt 60 has a contact surface that is in contact with the anchor bolt 24. In the closed state, which is shown in Figure 1, a first gap 101 is located between the brake bolt 60 and a stationary anchor bolt guide 25. The anchor bolt guide 25 guides the anchor bolt 24 during an opening and closing process.

[0062] As can be further seen from Figure 1, the brake spring 61 is arranged between the brake bolt 60 and the guide body 18. The brake bolt 60 has a flange which is provided with clearance relative to the guide body 18.

[0063] In the closed state, the first gap 101 is also formed between the contact surface of the brake bolt 60 and the armature bolt guide 25. The gap 101 has a first width which is smaller than a second width between the armature 20 and the inner pole 21 (see Figure 1) at a second gap 102. This ensures that a stroke of the brake bolt 60, which is preloaded in the axial direction by the compression spring 61, is smaller than a stroke of the armature 20. This allows sufficient fluid to flow from the lubricant chamber 4 via the throttle 63 into the damping chamber 62 during the injection process.

[0064] During the closing process, the armature pin 24 strikes the contact surface of the brake pin 60. This forces the brake pin 60 against the fluid in the damping chamber 62. Due to the throttle 63, the fluid cannot be forced out of the damping chamber 62 immediately, but rather slowly, thus enabling a damping effect during the closing process. This prevents excessive wear on the sealing seat 11 and the armature 20, since the closing process is dampened by the return of the brake pin 60.

[0065] The damping process is further supported by the brake spring 61 and hydraulic bonding of the brake bolt 60 to the anchor bolt guide 25. The damping chamber 62 prevents cavitation during the closing process in this area between the anchor bolt guide 25 and the contact surface of the brake bolt 60. Friction of the brake bolt 60 in the guide body 18 also delays the return process as well as the masses of the moving components to be accelerated in the entire lubricant chamber 4, which leads to a displacement of the lubricant in the enclosed lubricant chamber 4 and thus to additional deceleration during the closing process.

[0066] By selecting a diameter and / or a length of the throttle 63, the damping behavior can be adjusted individually for the respective gas injector.

[0067] It should be noted that a stop surface between the damping bolt 60 and the anchor bolt guide 25 can preferably be wedge-shaped, i.e., not at a right angle to a central axis XX of the gas injector. Alternatively or additionally, radial slots can be provided in the contact surface or the end face of the anchor bolt guide 25, which faces the brake bolt 60, thereby further reducing and preventing a cavitation effect.

[0068] The gas injector 1 shown in Figure 1 is pressure-compensated. This means that the closing element 3 is connected to the guide sleeve 9 via the first flexible sealing element 51. The first flexible sealing element 51, designed as a metal bellows, has an average diameter that is equal to the diameter of the sealing seat 11 against which the closing element 3 seals. This results in no pressure force acting on the closing element 3, so that the magnetic force required to open the closing element 3 can be kept very small and, in particular, is independent of the pressure of the gaseous fuel.

[0069] Thus, with the present invention, when the closing element 3 has been set in the open state by actuating the magnetic actuator 2 (movement of the closing element 3 to the left in Figure 1) and gas is injected, reliable damping can be carried out upon resetting the closing element 3 shortly before the closing element is pressed into the sealing seat 11. The brake bolt 60 is pressed in the direction of the damping chamber 62 by the armature bolt 24 and moves only as slowly as the lubricant is forced out of the damping chamber 62 through the throttle 63 into the lubricant chamber 4. Thus, a closing speed of the closing element 3 is significantly and effectively slowed down before the closing element hits the sealing seat 1. Thus, wear on the sealing seat 1 and the closing element 3 can be effectively reduced, whereby the braking device 6 continues to enable the gas injector to operate more quietly. A so-calledClosing bounce, in which an element hits a sealing seat hard and bounces back, can be effectively prevented.

[0070] The sealing seat 11 is designed as a conical sealing seat. The sealing seat 11 can also be designed as a flat sealing seat, so that the sealing surfaces on the seat plate 30a and the valve seat component 93 can be easily manufactured, e.g., by surface machining such as lapping.

[0071] Thus, the gas injector 1 can provide reduced wear on the moving parts, in particular on the sealing seat 11, armature 20, and in the armature pin 24, as well as the three needle guides. Tilting and bending of the valve needle 30 can be prevented, so that the opening and, in particular, closing processes can always be carried out smoothly. Furthermore, the sealed lubricant chamber 4 containing a liquid lubricant can significantly improve heat dissipation from the magnetic actuator 2. Furthermore, the two flexible sealing elements 51, 52 can prevent unwanted forces from acting on the closing element 3.

[0072] Figure 4 shows a gas injector with a closing element according to a second embodiment of the invention. Identical or functionally identical parts are designated by the same reference numerals as in the first embodiment.

[0073] In the second exemplary embodiment, the first and second needle guides 31, 32 are designed differently from the first exemplary embodiment. As in the first exemplary embodiment, the first and second needle guides 31, 32 each have an annular guide region 31a, 32a, but the webs are arranged such that a bowl-shaped needle guide is achieved. The webs are arranged at an acute angle a to the valve needle 30 and extend in the direction of the sealing seat 11. This allows a passage cross-section at the first and second needle guides 31, 32 to be significantly increased compared to the first exemplary embodiment. This allows larger quantities of gas to be guided through the first and second needle guides, which is an important aspect in gas injectors because the largest possible quantities of gas must be blown into the combustion chamber in the shortest possible time for the injection process.

[0074] The angle a between the webs of the first and second needle guides and the valve needle 30 is preferably in a range of 30° to 60° and is particularly preferably 45°. Otherwise, this embodiment corresponds to the previous embodiment, so reference can be made to the description given there.

[0075] Figure 5 shows a gas injector with a closing element according to a third exemplary embodiment of the invention. Identical or functionally identical parts are designated by the same reference numerals as in the previous exemplary embodiments. In the third exemplary embodiment, the first and second needle guides have exclusively webs without the annular guide region, which are arranged perpendicular to the valve needle 30. In this exemplary embodiment, three webs are provided. The guide regions 36 of the first and second needle guides 31, 32 are formed at the free ends of the webs; these guide regions, together with the valve seat component 93, guide the closing element 3.

[0076] Figure 6 shows a fourth embodiment of the invention, which is designed similarly to the third embodiment, wherein guide ribs are formed instead of the webs, which guide the needle in the valve seat component 93. A length L of the ribs in the axial direction is greater than a radial extent R, so that the elongated guide ribs are retained on the valve needle 30. Otherwise, this embodiment corresponds to the previous embodiments, so that reference can be made to the description given there. The third and fourth embodiments can be manufactured particularly cost-effectively by omitting the annular guide region.

Claims

Claims 1. Gas injector for injecting a gaseous fuel, comprising: - a magnetic actuator (2) with an armature (20), an inner pole (21) and a coil (22), - a closing element (3) with a valve needle (30), wherein the closing element (3) releases and closes a gas path (14) at a sealing seat (11), wherein the anchor (20) is connected to the closing element (3), - a closed lubricant chamber (4) which is filled with a lubricant and in which the armature (20) is arranged, wherein the lubricant ensures lubrication of the armature (20), - a flexible sealing element (51) which seals the lubricant chamber (4) against the gas path (14), - a return element (10) which is arranged in the lubricant chamber (4) and which returns the closing element (3) to a closed initial position, and - a first needle guide (31), a second needle guide (32) and a third needle guide (33), which are designed to guide the valve needle (30), - wherein the first needle guide (31) and the second needle guide (32) are arranged in the gas path (14) and the third needle guide (33) is arranged in the lubricant chamber (4).

2. Gas injector according to claim 1, wherein a first distance (A1) between the first needle guide (31) and the second needle guide (32) in the axial direction (XX) is smaller than a second distance (A2) between the second needle guide (32) and the third needle guide (33) in the axial direction (XX).

3. Gas injector according to one of the preceding claims, wherein the first needle guide (31) and / or the second needle guide (32) and / or the third needle guide (33) each have an annular guide area (31a, 32a) which is connected to the valve needle (30) via webs (31b, 32b) such that openings (31c, 32c) for fluid passage are provided between the webs. Gas injector according to claim 3, wherein the webs (31b, 32b) extend at an acute angle to the annular guide area (31a, 32a). Gas injector according to claim 4, wherein the webs are arranged in the flow direction downstream of the guide area. Gas injector according to claim 3, wherein the webs are arranged perpendicular to the valve needle (30).A gas injector according to claim 1 or 2, wherein the first needle guide (31) and / or the second needle guide (32) and / or the third needle guide (33) comprise exclusively webs arranged radially outward from the valve needle (30), with guide areas formed at the free ends of the webs, or wherein the first needle guide (31) and / or the second needle guide (32) and / or the third needle guide (33) are designed as guide ribs whose longitudinal extent (L) is greater than a radial extent (R). A gas injector according to any one of the preceding claims, wherein the closing element further comprises a plate (34) on which the flexible sealing element (51) is arranged. A gas injector according to any one of the preceding claims, wherein the first needle guide (31) and the second needle guide (32) are jointly guided on a valve seat component (93) on which the sealing seat (11) is also formed.A gas injector according to any of the preceding claims, wherein the third needle guide (33) is also configured to support the return element (10). A gas injector according to any of the preceding claims, wherein a third distance (A3) exists between the first needle guide (31) and the sealing seat. (11) is smaller than the first distance (A1) between the first needle guide (31) and the second needle guide (32).

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