Gas injector with robust needle guide

Abstract

The invention relates to a gas injector for injecting gaseous fuel, comprising an electromagnetic actuator (2) having an armature (20), an inner pole (21) and a coil (22); a closing element (3) having a valve needle (30), the closing element (3) releasing and closing a gas path (14) on a sealing seat (11), the armature (20) being 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, the lubricant ensuring lubrication of the armature (20); a flexible sealing element (51) which seals the lubricant chamber (4) with respect to the gas path (14); a restoring element (10) which is arranged in the lubricant chamber (4) and which resets the closing element (3) into a closed initial position; and a first needle guide (31), a second needle guide (32) and a third needle guide (33) provided for guiding the valve needle (30), the first needle guide (31) and the second needle guide (32) being arranged in the gas path (14) and the third needle guide (33) being arranged in the lubricant chamber (4).

Description

Technical Field

[0001] The invention relates to a gas injector for injecting gaseous fuels, in particular hydrogen or natural gas, etc., which has very robust and durable guidance characteristics for a long valve needle of a closing element of the gas injector. The gas injector is designed in particular for direct injection into a combustion chamber of an internal combustion engine. Background Art

[0002] Gas injectors of various designs are known from the prior art. The problem with gas injectors is that, due to the gaseous medium to be injected, lubrication by the medium is not possible, as is the case, for example, with fuel injectors that inject gasoline or diesel. This results in excessive wear during operation, especially in the area for guiding the valve needle, compared to fuel injectors for liquid fuels. Furthermore, due to the increasingly reduced size of internal combustion engines, a compact design is often required. Summary of the invention

[0003] However, the gas injector for injecting gaseous fuel according to the present invention with the features of claim 1 has the following advantages: the gas injector has particularly good guiding characteristics for the valve needle of the closing element of the gas injector. In particular, the tilting moment that may be applied to the valve needle by the reset element can be reliably absorbed and will not cause the valve needle to be tilted on the sealing seat. Therefore, the gas injector is sealed in a closed state on the sealing seat in all operating conditions. According to the present invention, this is achieved by the gas injector including an electromagnetic actuator with an armature, an inner pole and a coil. In addition, the gas injector includes a closing element with a valve needle, which releases and closes the gas path for the gaseous fuel on the sealing seat. The armature is connected to the closing element here. In addition, a closed lubricant chamber is provided, which is filled with a lubricant and a movable armature is arranged in the lubricant chamber. Here, the lubricant ensures lubrication of the armature so that no wear occurs on the armature during operation. Here, the lubricant chamber includes at least one flexible sealing element, especially a bellows, which seals the lubricant chamber relative to the gas path and thus ensures the axial movability of the closing element. In addition, the gas injector comprises a reset element, in particular a closing spring in the form of a cylindrical spring, wherein the reset element resets the closing element to a closed initial position. In addition, the gas injector comprises a first needle guide, a second needle guide and a third needle guide, which guide the valve needle during the opening process and the closing process. Here, the first needle guide and the second needle guide are arranged in the gas path, and the third needle guide is arranged in the lubricant chamber. The reset element is also arranged in the lubricant chamber. Therefore, the movement of the reset element and the third needle guide lubricated by the lubricant of the lubricant chamber does not produce wear or at most produces minimal, negligible wear. The first needle guide and the second needle guide arranged in the gas path are therefore located outside the lubricant chamber. If a tilting moment is applied to the valve needle by the reset element during operation, the tilting moment can be reliably absorbed by both the first needle guide and the second needle guide arranged in the gas path. Thus, the valve needle is prevented from bending by both the first needle guide and the second needle guide, which may be caused by the tilting moment that may occur. Thus, the sealing seat remains closed in all operating conditions or can prevent the valve needle from tilting on the sealing seat and thereby an insufficient closing process. Therefore, the valve needle is reliably guided by a dual guide outside the lubricant chamber and a guide in the lubricant chamber.

[0004] The dependent claims reveal preferred embodiments of the invention.

[0005] Preferably, a first distance A1 between the first needle guide and the second needle guide in the axial direction XX of the gas injector is smaller than a second distance A2 between the second needle guide and the third needle guide in the axial direction XX. As a result, any tilting moments that may occur are particularly well absorbed by the first needle guide and the second needle guide. The second distance A2 is preferably at least twice, more preferably at least three times, the first distance A1.

[0006] Further preferably, the first needle guide and / or the second needle guide and / or the third needle guide each have an annular guide area, which is connected to the valve needle of the closing element via a tab, so that there is a gap between the tabs for the passage of fluid. This is particularly advantageous for the first needle guide and the second needle guide arranged in the gas guide area of ​​the gas injector, so that the largest possible amount of gas can flow through the first guide area and the second guide area when the gas injector is opened. Here, the annular guide area is preferably closed along the entire periphery. In order to keep the friction as small as possible during the opening and closing process of the closing element, the width of the annular guide area is selected to be as small as possible. Particularly preferably, three tabs are provided here, which connect the valve needle to the annular guide area. Preferably, the tabs are arranged equidistantly along the periphery.

[0007] According to a particularly preferred configuration of the present invention, the tab between the valve needle and the annular guide area is arranged at an acute angle relative to the annular guide area. This makes it possible to increase the flow cross section in the area of ​​the guide, which is particularly advantageous for the first needle guide and the second needle guide located in the gas guide area. Preferably, the tab is arranged behind the guide area along the flow direction through the notch. Alternatively, the tab between the valve needle and the annular guide area of ​​the needle guide is arranged at a right angle relative to the valve needle.

[0008] According to another alternative configuration of the present invention, the first needle guide and / or the second needle guide and / or the third needle guide are only configured as tabs extending radially outward from the valve needle and having a guide area at their free end. Further alternatively, the first needle guide and / or the second needle guide and / or the third needle guide are configured as guide ribs, which have a larger extension in the axial direction than in the radial direction.

[0009] According to a particularly preferred embodiment of the present invention, a disk is also arranged on the valve needle, to which the flexible sealing element is fixed. This allows a simple connection between the closing element and the flexible sealing element that seals the lubricant chamber.

[0010] The first needle guide and the second needle guide are preferably guided on the same component. This component is preferably a cylindrical valve body on which the sealing seat is also arranged. As a result, the guide surfaces for the first needle guide and the second needle guide can be produced in one clamping, which provides great advantages in terms of manufacturing technology and also reduces manufacturing costs.

[0011] In order to further reduce the number of components, the third needle guide is preferably also provided for supporting a reset element arranged in the lubricant chamber. The third needle guide can preferably be configured as a spring disk having a notch for lubricant during the opening and closing of the closing element.

[0012] Further preferably, the third distance A3 between the first needle guide and the sealing seat is smaller than the first distance A1 between the first needle guide and the second needle guide. The third distance A3 is preferably smaller than half of the first distance A1 and particularly preferably smaller than one third of the first distance A1.

[0013] The closing element can be constructed in one piece or in multiple pieces with the two needle guides below and the disc for receiving the elastic element. For example, multiple discs, the disc for the guide and the disc for receiving the elastic element can be welded to the pin. The pin can also be formed in one piece with a seat disc, to which the disc for the valve needle guide and the disc for receiving the elastic element are welded.

[0014] The flexible sealing element is preferably a metal bellows. On the one hand, the metal bellows offers very good mobility in order to enable an axial movement of the closing element and, on the other hand, the metal bellows can thereby be arranged as close as possible to the hot combustion chamber of the internal combustion engine. This can further reduce the axial length of the gas injector. Alternatively, the flexible sealing element is a plastic bellows or a diaphragm or a rubber element.

[0015] It is further preferred that the gas injector has a conical seat or a spherical cone seat. Preferably, the closing element comprises a sealing disk at the end pointing toward the combustion chamber, which releases one or more through-holes on the sealing seat. The gas injector is preferably designed as an injector that opens outwards. This makes it possible to provide a sealing seat that is perpendicular to the longitudinal direction of the gas injector in a plane.

[0016] Furthermore, the gas injector preferably comprises a braking device arranged in the lubricant chamber, which is provided for braking the closing element during a resetting process of the gas injector from the open state into the closed state. The braking device comprises a stopper, a damping chamber which is in fluid connection with the lubricant chamber and an elastic braking element, in particular a spring. During the resetting process, the stopper and the elastic braking element are in operative connection with the closing element and / or the armature, wherein the stopper is also provided during the resetting process for displacing lubricant from the damping chamber in order to dampen the resetting of the stopper. Since part of the braking process is caused by the hydraulic bonding between the stopper and the stop member, against which the stopper rests in the open state of the gas injector, the formation of vapor bubbles in the liquid lubricant can be prevented by providing the damping chamber when overcoming the hydraulic bonding, so that wear due to cavitation can be prevented in particular.

[0017] The braking process is additionally assisted by utilizing the acceleration of the additional mass provided by the brake device. In addition, further braking is achieved by displacing lubricant between the armature and the tumbler. The return speed of the closing element can also be further reduced by the friction between the guide element and the tumbler. All of this reduces the impact force of the armature on the stop, so that the service life of the armature can also be further extended.

[0018] Further preferably, the tumbler comprises in particular a body with a stop surface, which is arranged on the side of the body of the tumbler pointing toward the closing element and can be operatively connected to the closing element and serves as a stop surface. The body is preferably cylindrical. Further preferably, an annular flange is arranged on the side of the body pointing toward the closing element. The annular flange preferably serves as a stop surface.

[0019] According to another preferred embodiment of the present invention, the elastic brake element of the brake device is arranged in the damping chamber, thereby achieving a particularly compact structure. The elastic brake element is preferably a compression spring, in particular a cylindrical spring.

[0020] Further preferably, the damping chamber is in fluid connection with the lubricant chamber via a guide gap of the tumbler.

[0021] Preferably, the gas injector further comprises a throttle which connects the damping chamber to the lubricant chamber. The throttle ensures that the damping process can be carried out in a defined manner, since the lubricant is then transferred from the damping chamber via the throttle into the lubricant chamber. The throttle is preferably a small connecting hole between the damping chamber and the lubricant chamber. The damping behavior of the brake device can be adjusted by selecting the geometric dimensions of the connecting hole, for example the diameter and / or the length of the hole.

[0022] Further preferably, the gas injector comprises an armature pin which bears against the closing element, wherein the armature pin is connected to the armature. The end of the armature pin facing away from the sealing seat of the gas injector is provided for contacting the tumbler in the closed state of the gas injector.

[0023] Preferably, oil, in particular synthetic oil, is used as lubricant. Alternatively, liquid fuel, in particular diesel or gasoline, is used. Further alternatively, grease is used as lubricant. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the accompanying drawings:

[0025] Figure 1 : A schematic cross-sectional view of a gas injector according to a first embodiment of the present invention;

[0026] Figure 2 : Figure 1 A schematic partial cross-sectional view of a gas injector;

[0027] Figure 3 : Figure 1 A schematic perspective view of a first needle guide and a second needle guide of a gas injector;

[0028] Figure 4 : A schematic perspective view of a first needle guide and a second needle guide of a gas injector according to a second embodiment of the present invention;

[0029] Figure 5 : A schematic perspective view of a first needle guide and a second needle guide of a gas injector according to a third embodiment of the present invention, and

[0030] Figure 6 : A schematic perspective view of a first needle guide and a second needle guide of a gas injector according to a fourth embodiment of the present invention. DETAILED DESCRIPTION

[0031] Refer to the following Figures 1 to 3 A gas injector 1 according to a first preferred embodiment of the present invention is described in detail.

[0032] As from Figure 1 It can be seen that a gas injector 1 for introducing gaseous fuel comprises an electromagnetic actuator 2 which moves an outwardly opening closing element 3 from a closed state into an open state. Figure 1 The closed state of the gas injector is shown here.

[0033] The electromagnetic actuator 2 comprises an armature 20 which is connected to the closing element 3 by means of an armature pin 24. Furthermore, the electromagnetic actuator 2 comprises an inner pole 21, a coil 22 and a magnet housing 23 which ensures a magnetic circuit of the electromagnetic actuator.

[0034] Furthermore, the gas injector 1 comprises a body 7 with a gas inlet 70, through which the gaseous fuel is supplied. Here, a valve housing 8 is fixed to the body 7, in which the electromagnetic actuator 2 is arranged. A housing sleeve 19 is connected to the valve housing 8, at the free end of which a sealing seat 11 is arranged on a valve seat component 93, on which the closing element 3 releases and closes the passage for the gaseous fuel.

[0035] exist Figure 1 Schematically shown in FIG. 1 are electrical connections 13 which are led via the body 7 and the magnet housing 8 to the electromagnetic actuator 2 .

[0036] Reference numeral 10 designates a reset element for the closing element 3 in order to reset the reset element to the position after the opening process. Figure 1 Shown in the closed state.

[0037] exist Figure 1 1 also shows the gas flow as a gas path 14 through the gas injector 1. Here, the gas flow starts at the gas inlet 70 and is then guided into the annular space 80 between the valve housing 8 and the body 7. The gas flow 14 continues here from the outer area of ​​the electromagnetic actuator 2 through the filter 15 to before the sealing seat 11. Here, the corresponding recesses provided in the corresponding components are Figure 1 Not all gaps are shown.

[0038] When the gas injector 1 is opened, the gaseous fuel then flows past the outer circumference of the electromagnetic actuator 2 and the opened sealing seat 11 into the combustion chamber 100 of the internal combustion engine. Figure 1 Indicated by arrow A.

[0039] The closing element 3 comprises a valve needle 30 having a seat disk 30a, which is arranged on the end of the closing element pointing toward the combustion chamber. The sealing seat 11 is formed here between the seat disk 30a and a valve seat component 93, which is a cylindrical tube.

[0040] 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 constructed integrally with the valve needle 30 or in multiple parts.

[0041] The closing element 3 further comprises a disc 34 arranged between the second needle guide 32 and the third needle guide 33 in the axial direction XX.

[0042] The gas injector 1 further comprises a closed lubricant chamber 4. The closed lubricant chamber 4 is completely or partially filled with a liquid lubricant, such as oil.

[0043] As from Figure 1 It can be seen that the lubricant chamber 4 is delimited by the first flexible sealing element 51, the inner pole 21, the magnet housing 23, the guide body 18 and the second flexible sealing element 52. The first flexible sealing element 51 and the second flexible sealing element 52 are each designed as a bellows.

[0044] It should be noted that, instead of a bellows, for example, a diaphragm or a hose or the like may also be used as the flexible sealing element 51 , 52 .

[0045] If further from Figure 1 As can be seen in the figure, the second flexible sealing element 52 is fixed to the energy storage spring disk 41, for example by means of a welded connection. In addition, the gas injector 1 comprises an energy storage pressure spring 40, which is supported on the body 7 and the second flexible sealing element 52 is prestressed by the energy storage spring disk 41. The connecting hole 18a is arranged in the guide body 18, so that the lubricant located in the lubricant chamber 4 is also in the area within the second flexible sealing element 52.

[0046] The first flexible sealing element 51 is fastened directly to the disk 34 on the closing element 3 and is connected at the other end to the guide sleeve 9. The third needle guide 33 is guided in the guide sleeve 9.

[0047] Therefore, the lubricant chamber 4 has two flexible sealing elements 51, 52 and an energy storage pressure spring 40. The energy storage pressure spring 40 applies a certain preload, for example 1×10 5 Pa to the lubricant in the lubricant chamber 4. If the lubricant is now squeezed out during the opening process due to the stroke of the closing element 3 or also due to thermal expansion or cooling of the lubricant, the overpressure / negative pressure that may be formed in the interior of the lubricant chamber 4 is compensated by the bias on the second flexible sealing element 52 in combination with the contraction of the energy storage pressure spring 40. Therefore, the flexible sealing element 51 cannot exert undesirable forces acting via the bellows effective surface on the closing element 3.

[0048] An armature pin 24, to which the armature 20 is fixed, is also arranged in the closed lubricant chamber 4. Since the lubricant chamber 4 is filled with a lubricant, such as oil or grease with a gasoline or diesel viscosity, etc., continuous lubrication of the armature 20 is achieved. This can compensate for the lack of lubrication of moving parts that occurs in the prior art when using gaseous fuels.

[0049] Here, the third needle guide 33 is also arranged in the lubricant chamber 4. Figure 2As can be seen in the figure, the third needle guide 33 is guided inside the guide sleeve 9. A reset element 10 is also arranged inside the guide sleeve 9, which is supported on the flange 9a of the guide sleeve 9 and the third needle guide 33. Therefore, the third needle guide 33 has two functions, namely guiding the valve needle 30 and supporting the reset element 10. Here, notches 33a are correspondingly provided in the third needle guide 33 so that the lubricant in the lubricant chamber 4 can pass through these notches.

[0050] The guide sleeve 9 is connected to the first flexible sealing element 51 , for example, by means of a welded connection.

[0051] Since the third needle guide 33 is arranged in the lubricant chamber 4 , sufficient lubrication is present here in all operating conditions of the gas injector, so that no wear occurs on the third needle guide during operation.

[0052] However, the first needle guide 31 and the second needle guide 32 are arranged in the gas path 14. Figure 3 As can be seen in detail, the first needle guide 31 and the second needle guide 32 are constructed identically. Here, the first needle guide 31 comprises an annular guide area 31a, which is connected to the valve needle 30 via three webs 31b. Between the webs, gaps 33c are formed for the fluid to pass through between the webs. The webs are designed to be as thin as possible in order to provide the largest possible flow cross section for the medium to be blown in.

[0053] The second needle guide 32 is constructed in the same manner as the first needle guide 31 with an annular guide region 32 a , three webs 32 b and corresponding recesses 32 c formed between the webs.

[0054] A particularly safe and precise guiding of the closing element 3 is thus possible by means of the annular guide areas 31a and 32a on the first needle guide and the second needle guide. During operation, tilting moments can now be applied to the closing element by means of the reset element 10 and, if necessary, also by means of the first flexible sealing element 51 which is constructed as a bellows. However, these tilting moments can be absorbed by the first needle guide and the second needle guide, so that the valve needle 30, which is constructed with the smallest possible cross-section and has a certain structural length in the axial direction XX, can be flexible and bendable due to such tilting moments. Due to the flexibility of the valve needle, only small lateral forces are present on the needle guide in the event of a tilting moment from the closing element or the elastic element. As can be seen from Figure 1 It can be seen that the first distance A1 between the first needle guide 31 and the second needle guide 32 is smaller than the second distance A2 between the second needle guide 31 and the third needle guide 33 .

[0055] Therefore, the gas injector can be designed to be very slender and have a certain structural length, and during operation, no undesirable lateral forces can be applied to the valve needle due to the tilting moment of the reset element 10 or the first flexible sealing element 51, so that the gas injector can always be sealed in all operating conditions and can be reliably reset to the closed sealing state even after the opening process. Therefore, the wear on the valve needle guide can also be negligible.

[0056] Furthermore, the third distance A3 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. This additionally assists the closing process so that the sealing seat can always be closed correctly.

[0057] A brake device 6 is also arranged in the closed lubricant chamber 4. The brake device 6 comprises a brake tumbler 60, a brake spring 61 and a damping chamber 62. The damping chamber 62 is in fluid connection with the lubricant chamber 4.

[0058] The stopper 60 and the elastic brake element 61 are in operative connection with the closing element 3 during the return of the gas injector to the closed initial position. During the return process, the lubricant is displaced from the damping chamber 62 into the lubricant chamber 4 so that when the stopper 60 is returned to the closed state of the gas injector ( Figure 1 ) to achieve additional damping. The tumblers 60 are guided in the guide body 18 .

[0059] If further from Figure 1 It can be seen that the damping chamber 62 is formed directly on the tumbler 60 on the side of the tumbler 60 facing away from the sealing seat 11. The damping chamber 62 is connected to the connecting hole 18a and thus to the main area of ​​the lubricant chamber 4 via a throttle 63, which is a small hole. The brake spring 61 is arranged in the spring chamber 67.

[0060] The brake tumbler 60 has a contact surface that contacts the armature tumbler 24. Figure 1 In the closed state shown, there is a first gap 101 between the tumbler 60 and the stationary armature bolt guide 25. The armature bolt guide 25 guides the armature bolt 24 during the opening and closing process.

[0061] If further from Figure 1 It can be seen in FIG. 1 that the brake spring 61 is arranged between the brake tumbler 60 and the guide body 18. The brake tumbler 60 has a collar which is provided with a clearance with the guide body 18.

[0062] In the closed state, a first gap 101 is also formed between the stop surface of the brake tumbler 60 and the armature bolt guide 25. The gap 101 has a first width, which is smaller than the second width between the armature 20 and the inner pole 21 at the second gap 102 (see Figure 1 ). This ensures that the stroke of the tumbler 60 preloaded in the axial direction by the compression spring 61 is smaller than the stroke of the armature 20. Therefore, during the injection process, sufficient fluid can flow from the lubricant chamber 4 via the throttle 63 into the damping chamber 62.

[0063] During the closing process, the armature pin 24 strikes the stop surface of the stop tumbler 60. As a result, the stop tumbler 60 is pressed against the fluid in the damping chamber 62. Due to the throttle 63, the fluid cannot be pressed out of the damping chamber 62 immediately, but rather slowly, so that a damping effect can be achieved during the closing process. This prevents excessive wear on the sealing seat 11 and the armature 20, since the closing process is damped by the return of the stop tumbler 60.

[0064] The damping process is further assisted by the hydraulic bonding of the brake spring 61 and the tumbler 60 to the armature bolt guide 25. During the closing process, cavitation can be prevented in the region between the armature bolt guide 25 and the stop surface of the tumbler 60 by the damping chamber 62. The friction of the tumbler 60 in the guide body 18 also delays the return process and also the mass of the moving part to be accelerated in the entire lubricant chamber 4, which mass leads to the displacement of lubricant in the closed lubricant chamber 4 and thus to additional braking during the closing process.

[0065] By selecting the diameter and / or the length of the throttle 63 , the damping behavior can be adjusted individually for each gas injector.

[0066] It should be noted that the stop surface between the damping pin 60 and the armature pin guide 25 can preferably be designed in a wedge-shaped manner, i.e. not at right angles to the central axis XX of the gas injector. Alternatively or additionally, a radial gap can be provided in the stop surface or end face of the armature pin guide 25 pointing toward the brake pin 60, thereby further reducing and preventing cavitation effects.

[0067] exist Figure 1 The gas injector 1 shown in FIG is pressure-balanced here. That is, the closing element 3 is connected to the guide sleeve 9 via a first flexible sealing element 51, wherein the first flexible sealing element 51, which is designed as a metal bellows, has an average diameter that is equal to the diameter at the sealing seat 11, on which the closing element 3 seals. As a result, no pressure is generated on the closing element 3, so that the magnetic force required for opening the closing element 3 can be kept very low and is in particular independent of the pressure of the gaseous fuel.

[0068] Therefore, according to the present invention, when the closing element 3 has been adjusted to the open state by actuating the electromagnetic actuator 2 (the closing element 3 is in the open state), Figure 1When the closing element 3 is repositioned (movement to the left in the cylinder) and gas is injected, reliable damping can be performed shortly before the closing element is pressed into the sealing seat 11 when the closing element 3 is reset. Here, the brake tumbler 60 is pressed by the armature bolt 24 in the direction of the damping chamber 62 and moves only as slowly as the lubricant is pressed out of the damping chamber 62 through the throttle 63 into the lubricant chamber 4. Therefore, the closing speed of the closing element 3 is significantly and effectively braked before the closing element hits the sealing seat 1. As a result, the wear on the sealing seat 11 and the closing element 3 can be effectively reduced, wherein the brake device 6 can continue to realize the operation of the gas injector in a quieter manner. The so-called closing bounce can also be effectively prevented, in which the element hits the sealing seat hard and bounces back.

[0069] The sealing seat 11 is configured as a conical sealing seat. The sealing seat 11 can also be configured as a flat sealing seat, so that the sealing surfaces on the seat plate 30a and the valve seat member 93 can be simply manufactured, for example, by surface treatment such as grinding.

[0070] Thus, the gas injector 1 can provide reduced wear on the moving parts, in particular on the sealing seat 11, the armature 20, and in the armature pin 24 and the three needle guides. Tilting and bending of the valve needle 30 can be prevented, so that the opening process and in particular the closing process can always be carried out without problems. In addition, the heat dissipation from the electromagnetic actuator 2 can be significantly improved by the closed lubricant chamber 4 with liquid lubricant. In addition, the two flexible sealing elements 51, 52 can prevent undesirable forces from acting on the closing element 3.

[0071] Figure 4 A gas injector with a shut-off element according to a second exemplary embodiment of the invention is shown. Identical or functionally identical components are denoted by the same reference numerals as in the first exemplary embodiment.

[0072] In the second embodiment, the first needle guide 31 and the second needle guide 32 are constructed differently from the first embodiment. The first needle guide 31 and the second needle guide 32 respectively have annular guide areas 31a, 32a as in the first embodiment, but the webs are arranged so as to realize a bowl-shaped needle guide. Here, the webs are arranged at an acute angle α to the valve needle 30 and extend in the direction of the sealing seat 11. As a result, the flow cross-section on the first needle guide 31 and the second needle guide 32 can be significantly increased compared to the first embodiment. As a result, a larger amount of gas can be guided through the first needle guide and the second needle guide, which is an important aspect in gas injectors because the largest possible amount of gas must be blown into the combustion chamber in the shortest possible time for the injection process.

[0073] The angle α between the webs of the first and second needle guide and the valve needle 30 is preferably in the range of 30° to 60° and is particularly preferably 45°. Otherwise, this embodiment corresponds to the preceding embodiment, so that reference can be made to the description given there.

[0074] Figure 5 A gas injector with a closing element according to a third embodiment of the invention is shown. Identical or functionally identical components are indicated with the same reference numerals as in the previous embodiments. In the third embodiment, the first needle guide and the second needle guide only have tabs without annular guide areas, which are arranged perpendicular to the valve needle 30. In this embodiment, three tabs are provided. The guide areas 36 of the first needle guide 31 and the second needle guide 32 are formed at the free ends of the tabs, which guide areas and the valve seat component 93 are responsible for guiding the closing element 3.

[0075] Figure 6 A fourth exemplary embodiment of the invention is shown, which is constructed similarly to the third exemplary embodiment, wherein guide ribs are provided instead of webs, which guide ribs provide guidance for the needle in the valve seat component 93. The length L of the ribs in the axial direction is greater than the radial extension R, so that elongated guide ribs are obtained on the valve needle 30. Otherwise, this exemplary embodiment corresponds to the preceding exemplary embodiments, so that reference can be made to the description given there.

[0076] The third and fourth exemplary embodiments can be produced particularly cost-effectively by dispensing with the annular guide region.

Claims

1. A gas injector for blowing gaseous fuel, comprising: - an electromagnetic 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 the gas path (14) on the 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) relative to the gas path (14), a restoring element (10) which is arranged in the lubricant chamber (4) and which resets the closing element (3) into a closed initial position, and a first needle guide (31), a second needle guide (32) and a third needle guide (33) arranged 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. The gas injector according to claim 1, wherein: A first distance (A1) between the first needle guide (31) and the second needle guide (32) along the axial direction (XX) is smaller than a second distance (A2) between the second needle guide (32) and the third needle guide (33) along the axial direction (XX).

3. A gas injector according to any one of the preceding claims, wherein: The first needle guide member (31) and / or the second needle guide member (32) and / or the third needle guide member (33) respectively have an annular guide area (31a, 32a), which is connected to the valve needle (30) via a web (31b, 32b) so that a gap (31c, 32c) for fluid to pass through exists between the webs.

4. The gas injector according to claim 3, wherein: The webs (31b, 32b) extend at an acute angle to the annular guide region (31a, 32a).

5. The gas injector according to claim 4, wherein: The web is arranged downstream of the guide region in the flow direction.

6. The gas injector according to claim 3, wherein: The web is arranged perpendicular to the valve needle (30).

7. The 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) have only webs arranged radially outward from the valve needle (30), wherein a guide region is formed at the free end 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 constructed as guide ribs, and the longitudinal extension dimension (L) of the guide ribs is greater than the radial extension dimension (R).

8. A gas injector according to any one of the preceding claims, wherein: The closing element further comprises a disk (34) on which the flexible sealing element (51) is arranged.

9. A gas injector according to any one of the preceding claims, wherein: The first needle guide element (31) and the second needle guide element (32) are guided together on a valve seat component (93), on which the sealing seat (11) is also formed.

10. A gas injector according to any one of the preceding claims, wherein: The third needle guide (33) is also configured to support the resetting element (10).

11. A gas injector according to any one of the preceding claims, wherein: A third distance (A3) between the first needle guide (31) and the sealing seat (11) is smaller than a first distance (A1) between the first needle guide (31) and the second needle guide (32).

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