Gas injector

Abstract

The present invention relates to a gas injector for injecting a gaseous fuel, comprising: a magnetic actuator (2) with an armature (20), an internal pole (21) and a coil (22); a closure element (3) with a valve needle (31) and an armature pin (24), wherein the valve needle (31) releases and closes a gas path (14) at a sealing seat (11) arranged at a first end of the gas injector, wherein the armature (20) is connected to the armature pin (24) and the armature pin (24) is effectively connected to the valve needle (31); a closed lubricant space (4) which is filled with a liquid (40), as lubricant, and with a gas (41) and in which the armature (20) and the armature pin (24) are arranged, wherein the lubricant provides a lubricating effect in the lubricant space (4); a return element (10) which returns the closure element (3) to the closed starting position; a damping device (6) which is arranged in the lubricant space (4), wherein the damping device (6) is designed to damp a closing movement of the closure element (3); a compensation space (5) which is part of the lubricant space (4) and in which liquid (40) and gas (41) are arranged; and an anti-mixing apparatus (100) which is arranged in the compensation space (5) and is designed to prevent a mixing of liquid (40) and gas (41) in order to prevent a production of foam in the compensation space (5).

Description

[0001] Description

[0002] title

[0003] State of the art

[0004] The present invention relates to a gas injector for injecting a gaseous medium, such as hydrogen, natural gas, methane, LPG, ammonia or the like, into a combustion chamber of an internal combustion engine with improved damping properties by means of a damper with a very safe operating behavior.

[0005] Gas injectors are known in various designs from the prior art. Due to the relatively high gas pressures, a closing element, especially a valve needle, makes a hard impact against a sealing seat, particularly during a closing process. To avoid unnecessarily shortening the service life of the gas injector, damping devices should be provided. To avoid unnecessarily increasing manufacturing costs and maintenance, simple solutions are preferable.

[0006] Disclosure of the invention

[0007] The gas injector according to the invention for injecting a gaseous fuel with the features of claim 1 has the advantage that simple and reliable damping of a closing element is possible during the closing process of the gas injector. The damping is ensured here over the entire service life of the gas injector. In particular, the damping is also very robust and cost-effective and thus suitable for mass production of gas injectors. Furthermore, the damping according to the invention requires only a very small installation space. The damping during the closing process also prevents vibration excitation of other components of the gas injector, so that loads on the other components during operation can be significantly reduced. Furthermore, the measures according to the invention can prevent foaming processes inside a lubricant chamber containing a liquid and a gas. This can ensure very stable function of the gas injector.Furthermore, it is also possible to arrange the gas injector not only vertically, i.e., with a central axis of the gas injector arranged vertically, but also in any inclined installation position. Thus, the gas injector according to the invention is suitable for use in internal combustion engines from different manufacturers, where the installation position may deviate slightly, particularly from a vertical axis.

[0008] This is achieved according to the invention in that the gas injector has a magnetic actuator with an armature, an inner pole and a coil. Furthermore, the gas injector comprises a closing element with a valve needle, wherein the closing element opens and closes a gas path at a first end of the gas injector at a sealing seat. As a result, gas is blown into a combustion chamber, for example, or the blowing in is terminated. The closing element further comprises an armature bolt which is connected to the armature and is operatively connected to the valve needle. The valve needle and the armature bolt are preferably rod-like components which rest loosely against one another at opposite end surfaces and are movable independently of one another. The gas injector further comprises a lubricant chamber which is closed off by means of a lubricant housing and is filled with a liquid as lubricant and a gas.The armature and the armature bolt are arranged in the lubricant chamber, wherein the lubricant provides a lubricating effect for the components located in the lubricant chamber. A return element returns the closing element to a closed initial position. The lubricant chamber is preferably provided as a closed chamber by means of a flexible sealing element, in particular a bellows, wherein the flexible sealing element is arranged on the closing element. The flexible sealing element seals the lubricant chamber against the gas to be injected on a passing gas path. Furthermore, the gas injector comprises a damping device for dampening a closing process of the closing element, which damping device is arranged in the lubricant chamber. Furthermore, the gas injector comprises a compensation chamber in which the liquid and the gas are arranged.The partially gas-filled lubricant chamber thus enables easy volume expansion in the event of temperature-related volume changes in components and / or the fluid during operation. The compensation chamber is a subchamber of the lubricant chamber. The gas in the lubricant chamber is located in the compensation chamber of the gas injector during operation. Furthermore, the gas injector includes an anti-mixing device located in the compensation chamber and designed to prevent mixing of fluid and gas in the lubricant chamber. This prevents foam formation, which could negatively impact the function of the gas injector.

[0009] The compensation chamber is preferably located at an end of the gas injector facing away from the sealing seat. If the gas injector is installed vertically or essentially vertically, the gas in the lubricant chamber collects in the compensation chamber at the opposite end of the lubricant chamber. The anti-mixing device located in the compensation chamber thus prevents foam formation. Foam formation must be avoided in particular to prevent gas bubbles from entering the damping device and reducing the damping properties of the gas injector. This would lead to a shortened service life of the gas injector.

[0010] According to the invention, a separation between liquid and gas in the lubricant chamber can thus be achieved, even during operation. This makes the gas injector particularly suitable for inclined installation positions other than vertical. Depending on the internal combustion engine of an internal combustion engine manufacturer, the gas injector cannot always be installed in an absolutely vertical position. The gas injector according to the invention thus enables increased flexibility with regard to installation positions and provides very robust and stable operation throughout its entire service life.

[0011] The subclaims show preferred developments of the invention.

[0012] The lubricant chamber is enclosed by the lubricant housing, which preferably comprises a plurality of components. The ratio of liquid, i.e., the liquid lubricant to the gas in the lubricant chamber, is preferably in a range from 70 / 30 vol.% to 95 / 5 vol. Particularly preferably, the ratio of liquid to gas is in a range from 80 / 20 vol.% to 90 / 10 vol. Further preferably, the ratio of liquid to gas in the lubricant chamber is approximately 85 to 15 vol.%.

[0013] The damping device preferably comprises a damping piston, a damping housing, a throttle, and a damping chamber formed in the damping housing. The throttle connects the damping chamber to the compensation chamber. A guide region is formed between the damping piston and the damping housing. This guides the damping piston in the damping housing. The guidance preferably takes place over the entire axial length of the damping piston. The guide play between the damping piston and the damping housing is very tight. The throttle is preferably located in a central axis of the gas injector. Due to the throttle, very high local flow velocities of the fluid in the lubricant chamber can occur during operation. These flow velocities are slowed down by the anti-mixing device according to the invention to prevent foam formation.

[0014] Preferably, the throttle of the damping device is designed such that a throttle length of the throttle in the axial direction of the gas injector is less than or equal to a throttle diameter. By selecting the throttle length and / or the throttle diameter, the throttle properties can be easily adjusted. This allows, in particular, the speeds at which the fluid flows through the throttle to be adjusted, thus adjusting the damping properties.

[0015] The damping chamber is preferably pot-shaped, and the throttle is located at the bottom of the pot-shaped damping chamber. This enables a particularly compact and simple design.

[0016] For a cost-effective design, the anti-mixing device preferably enables direct fluid communication between the liquid and the gas in the lubricant chamber. This allows the anti-mixing device, in particular, to be constructed very simply and cost-effectively, without the need for expensive special components such as membranes or the like. Thus, there is no fixed separation between the liquid and the gas in the lubricant chamber. The anti-mixing device preferably comprises an intermediate component which is arranged in the compensation chamber. The intermediate component is thus arranged in the axial direction between the damping device and the end of the lubricant chamber facing away from the sealing seat. The intermediate component divides the compensation chamber into a first and a second sub-chamber, wherein the intermediate component has at least one connecting opening which connects the first to the second sub-chamber.In the installed position, fluid is arranged on both the inside and outside of the intermediate component. In other words, the intermediate component is completely surrounded by fluid in the installed position. The connecting opening, which is preferably designed as a small-diameter bore, can thus reduce a potentially high fluid flow velocity, preventing the fluid from foaming in the lubricant chamber during operation.

[0017] Alternatively, the anti-mixing device comprises an intermediate component in the compensation chamber, which divides the compensation chamber into a first and a second sub-chamber. The intermediate component has a plurality of capillary connecting holes and is covered with liquid on both sides. The capillary connecting holes also provide only small connecting cross-sections between the first and second sub-chambers in the compensation chamber, thereby reducing flow velocities and thus the risk of foaming in the compensation chamber.

[0018] According to a further preferred alternative, the anti-mixing device comprises an intermediate component in the compensation chamber, which divides the compensation chamber into a first and a second sub-chamber, wherein the intermediate component has continuous connecting paths for connecting the first to the second sub-chamber. The connecting paths are preferably undefined and can be provided, for example, by porous sections and / or sieve meshes and / or steel wool inserts or the like. The continuous connecting paths have a very small maximum diameter, preferably less than 1 mm and in particular less than 0.5 mm. According to a further alternative embodiment of the invention, the anti-mixing device has an intermediate component which is arranged in the compensation chamber and has a chimney-like calming chamber for calming the flow of the liquid during operation.The chimney-like calming chamber of the intermediate component is directly connected to the damping device, so that during operation, a liquid supplied at high speed can be decelerated and calmed in the chimney-like calming chamber. The calming chamber is designed to be open or closed to the compensation chamber. The chimney-like calming chamber is preferably located in the central axis of the gas injector. If the chimney-like calming chamber is closed to the compensation chamber, the intermediate component preferably has an annular base with at least one connecting bore to connect the damping device to the remaining compensation chamber. If the chimney-like calming chamber is designed to be open to the compensation chamber, the chimney-like calming chamber has, for example, porous areas or areas provided with steel mesh or areas provided with steel wool or the like.Thus, the chimney-like settling chamber has liquid-permeable walls, which establishes the connection between the interior of the chimney-like settling chamber and the rest of the compensation chamber.

[0019] According to a further alternative of the present invention, the anti-mixing device in the compensation chamber comprises a first and a second inner diameter, which are different. The first inner diameter is directed toward the sealing seat and is smaller than the second inner diameter, which is formed in the region of the compensation chamber facing away from the sealing seat. The gas in the lubricant chamber is arranged in the region of the larger second inner diameter of the compensation chamber. The second inner diameter is preferably at least 1.5 times larger than the first inner diameter.

[0020] According to a further alternative embodiment of the invention, the anti-mixing device comprises a tubular device that projects into the compensation chamber. The compensation chamber and the damping device are fluidly connected via the tubular device. The tubular device is preferably a hollow cylinder, in particular arranged in a central axis of the gas injector, or a bent tube or the like with a lateral intake opening. According to a further preferred embodiment of the present invention, the anti-mixing device comprises a pressure-controlled valve. The pressure-controlled valve is configured to close a fluid connection between the compensation chamber and the damping device during the opening process of the gas injector and to open it during the closing process of the gas injector. The pressure-controlled valve is preferably a ball valve with a freely movable ball with two sealing seats.

[0021] Further preferably, the anti-mixing device is designed such that direct fluid communication between the liquid and the gas is prevented. This creates a clear separation between gas and liquid, so that no foaming can occur in the liquid during operation. The separating anti-mixing device is preferably a flexible element arranged in the compensation chamber, in particular a flexible membrane, which separates the liquid from the gas in the compensation chamber. Alternatively, the flexible element is an elastomer element filled with gas, which has a plurality of enclosed gas bubbles. The flexible element can also be prestressed by means of spring elements. According to a further alternative for a separating anti-mixing device, it is preferably provided that the anti-mixing device comprises a piston arrangement with a movable piston which separates the gas and the liquid.The piston is preferably spring-loaded and is moved by pressure differences in the lubricant chamber.

[0022] The gas injector is further preferably configured for directly injecting a gas into a combustion chamber of an internal combustion engine. The gas injector is further preferably an outward-opening gas injector.

[0023] Short description of the drawings

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

[0025] Figure 1 is a schematic sectional view of a gas injector according to a first preferred embodiment of the invention, Figure 2 is an enlarged partial sectional view of a damping device and a compensation chamber of the gas injector of Figure 1,

[0026] Figure 3 is a partial sectional view of a gas injector according to a second embodiment of the invention,

[0027] Figure 4 is a partial sectional view of a gas injector according to a third

[0028] Embodiment of the invention,

[0029] Figure 5 is a partial sectional view of a gas injector according to a fourth

[0030] Embodiment of the invention,

[0031] Figure 6 is a partial sectional view of a gas injector according to a fifth

[0032] Embodiment of the invention,

[0033] Figure 7 is a partial sectional view of a gas injector according to a sixth embodiment of the invention,

[0034] Figure 8 is a partial sectional view of a gas injector according to a seventh

[0035] Embodiment of the invention,

[0036] Figure 9 is a partial sectional view of a gas injector according to an eighth

[0037] Example of design in vertical installation position,

[0038] Figure 10 is a partial sectional view of the gas injector of Figure 9 in an angular installation position,

[0039] Figure 11 is a partial sectional view of a gas injector according to a ninth embodiment in a vertical installation position,

[0040] Figure 12 is a partial sectional view of the gas injector of Figure 11 in an angular installation position,

[0041] Figure 13 is a partial sectional view of a gas injector according to a tenth embodiment of the invention, Figure 14 is a partial sectional view of a gas injector according to an eleventh embodiment of the invention,

[0042] Figure 15 is a partial sectional view of a gas injector according to a twelfth embodiment of the invention, and

[0043] Figure 16 is a partial sectional view of a gas injector according to a thirteenth embodiment of the invention.

[0044] Preferred embodiments of the invention

[0045] A gas injector 1 according to a first preferred embodiment of the invention will be described in detail below with reference to Figures 1 and 2.

[0046] Figure 1 shows the closed state of the gas injector 1.

[0047] As can be seen from Figure 1, the gas injector 1 for injecting a gaseous fuel into a combustion chamber 30 comprises a magnetic actuator 2. The magnetic actuator 2 brings a closing element 3, which in this embodiment is an outwardly opening valve needle, from a closed state to an open state.

[0048] The magnetic actuator 2 comprises an armature 20, which rests against 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.

[0049] The gas injector 1 further comprises a main body 7 with a connection area 70, through which the gaseous fuel is supplied to an interior area of ​​the gas injector. A valve housing 8 is fixed to the main body 7, to which a housing sleeve 19 and a valve tube 90 are connected in the axial direction XX of the gas injector. A sealing seat 11 is provided at the free end of the valve tube 90.

[0050] The closing element 3 opens or closes a passage for the injection of the gaseous fuel. Figure 1 schematically shows an electrical connection 13, which is routed through the main body 7 to the magnetic actuator 2.

[0051] The closing element 3 is returned from the open position to the closed position shown in Figure 1 by means of a return element 10. In Figure 1, a gas path 14 is schematically indicated by the arrows in the gas injector. The gas path is essentially routed around the internal components of the gas injector. Accordingly, openings are arranged in the components of the gas injector.

[0052] The gas injector 1 further comprises a sealed lubricant chamber 4, which is filled with a liquid 40 as lubricant, preferably oil, and a gas 41, preferably air. As can be seen from Figure 1, the lubricant chamber 4 is formed by a bellows 51, which is fixed to the closing element 3, a sleeve 52, the inner pole 21, a damping housing 60, and a compensation chamber 5. The compensation chamber 5 is arranged at the end of the lubricant chamber 4 facing away from the sealing seat 11.

[0053] The gas injector 1 is shown in a vertical installation position. The axial direction XX is oriented vertically. This ensures that the gas 41 collects in the compensation chamber 5. A dividing line 43 between the gas 41 and the liquid 40 is schematically shown in Figures 1 and 2.

[0054] The largest part of the lubricant chamber 4 is filled with the liquid lubricant.

[0055] This ensures, in particular, lubrication of the armature 20 during operation. The return element 10 is also arranged in the lubricant chamber.

[0056] Furthermore, the gas injector 1 comprises a damping device 6, which is arranged in the lubricant chamber 4. The damping device 6 is arranged axially after the armature 20, starting from the sealing seat.

[0057] The damping device 6 is shown in detail in Figure 2. The damping device 6 comprises a damping piston 61, the damping housing 60, a throttle 62, and a damping chamber 63 arranged in the damping housing 60. The damping chamber 63 is pot-shaped, with the damping piston 61 being partially arranged in the damping chamber.

[0058] The damping piston 61 is cylindrical and has a through-opening 64 which runs in a central axis of the gas injector.

[0059] The damping device 6 further comprises a return element 65 for returning the damping piston 61 to the initial position shown in Figure 2.

[0060] As can be seen from Figure 2, a front end 24a of the armature bolt 24 facing away from the sealing seat is in direct contact with a front face 61b of the damping piston 61. The armature bolt 24 is guided in a stationary guide component 25. In the closed state of the gas injector, a gap 26 exists between the front face of the damping piston 61 facing the sealing seat and the guide component 25. The return element 65 is preloaded and supported between a flange 61a of the damping piston 60 and the damping housing 60.

[0061] The gas injector 1 further comprises an anti-mixing device 100. The anti-mixing device 100 is arranged in the compensation chamber 5. This divides the compensation chamber into a first sub-chamber 5a and a second sub-chamber 5b. The first sub-chamber 5a is completely filled with liquid, and the second sub-chamber 5b is partially filled with liquid and partially filled with gas.

[0062] The anti-mixing device 100 comprises an intermediate component 101 with a plurality of connecting openings 102. The connecting openings 102 serve to provide fluid communication between the first sub-chamber 5a and the second sub-chamber 5b. The connecting openings 102 are preferably small bores.

[0063] As can be seen in particular from Figure 2, the intermediate component 101 is thus covered with liquid on both an inner side 101a and an outer side 101b. In other words, the intermediate component 101 is arranged completely in the liquid in the lubricant chamber 4. The anti-mixing device 100 is designed to prevent mixing of gas and liquid in the compensation chamber 5 as far as possible, in particular to prevent foam formation during operation. Foam formation during operation poses a major threat to the function of the gas injector and in particular to the function of the damping device 6. Should gas bubbles enter the area of ​​the damping device 6, there is a risk that the damping device 6 will no longer provide adequate damping for the opening and closing process of the closing element.In particular, this can lead to time delays and inconsistent damping functions, so that during operation the closing element can be damaged by strong impact on the sealing seat 11.

[0064] The function of the gas injector according to the invention is as follows. When the gas injector is to be opened, the magnetic actuator 2 is energized, thereby pulling the armature 20, which is firmly connected to the armature bolt 24, toward the inner pole 21. Since the armature bolt 24 is in direct contact with the closing element 3, the closing element 3 is lifted from the sealing seat 11, allowing gas to be injected into the combustion chamber 30.

[0065] In the damping device 6, the spring force of the return element 65 moves the damping piston 61 toward the guide component 25, which is indicated by arrow A in Figure 2. This overcomes the gap 26 and increases the volume of the damping chamber 63. Lubricant can flow into the damping chamber 63 via the throttle 62 and the through-opening 64.

[0066] When the gas injector closes, the current supply to the magnetic actuator 2 is stopped, so that the return element 10 returns the closing element 3 and the armature pin 24 back toward their closed position. The armature pin 24 comes into contact with the end face 61b of the damping piston 61 and moves it in the opposite direction to the opening direction A.

[0067] Since only a very narrow guide gap 6a exists between the damping piston 61 and the damping housing 60 at a guide area 66, fluid must be displaced from the damping chamber 63 in order to return the damping piston 60. Since the guide gap 6a in the guide area 66 is very narrow, this displacement occurs essentially exclusively via the throttle 62 into the compensation chamber 5.

[0068] Thus, liquid from the throttle 62 enters the first sub-chamber 5a of the compensation chamber 5 at high velocity, which is shown in Figure 2 by the arrows B. Without the anti-mixing device, a very strong flow would be generated at the liquid surface in the compensation chamber 5 by liquid entering at high velocity, which could lead to foam formation.

[0069] The anti-mixing device 100 according to the invention with the intermediate component 101 in the compensation chamber 5 now prevents a direct inflow of the accelerated fluid. The accelerated fluid strikes the inner side 101a of the intermediate component 100 and is significantly decelerated. Since the connecting openings 102 have only very small diameters, this prevents rapidly flowing fluid from entering the second subchamber 5b of the compensation chamber 5. This prevents the generation of foam during operation. Thus, there is also no risk of gas bubbles entering the area of ​​the damping device 6 and in particular the area of ​​the throttle or the damping chamber 63.

[0070] Since the dimensions of the throttle 62 can be manufactured very precisely, in addition to precise damping of the closing element 3 via the armature bolt and the damping piston 61, it is also possible to adjust the speed of the fluid exiting the throttle. In particular, throttling is independent of the axial length of the guide area 66 between the damping piston 61 and the damping housing 60.

[0071] Further embodiments of the invention are described in detail below, wherein the same components are designated by the same reference numerals as in the first embodiment.

[0072] Figure 3 shows a gas injector 1 according to a second embodiment of the invention. The anti-mixing device 100 of the second embodiment comprises an intermediate component 101 with a plurality of capillary connecting bores 103. As shown in Figure 3, a plurality of capillaries are provided to connect the first subchamber 5a to the second subchamber 5b. The capillary connecting bores 103 effectively prevent gas bubbles from passing toward the damping device 6.

[0073] Figure 4 shows a third embodiment, wherein the anti-mixing device 100 comprises an intermediate component 101 with integrated, continuous connection paths. In the embodiment of Figure 4, this is implemented by areas provided with steel wool 104. The continuous connection paths with a very small maximum cross-section, in particular less than 1 mm, preferably less than 0.5 mm, can, however, also be provided by porous component areas and / or sieve meshes or the like.

[0074] The fourth embodiment shown in Figure 5 shows an intermediate component 101 with a chimney-like calming chamber 105. The chimney-like calming chamber 105 is provided in a hollow cylinder 106. The hollow cylinder 106 lies in the central axis, in which the throttle 62 is also located. A liquid escaping through the throttle 62 at high velocity (arrow B) enters the chimney-like calming chamber 105 and is thereby decelerated. The hollow cylinder 106 has an end 106a facing away from the sealing seat, which is firmly connected to the bottom of the compensation chamber 5. A connection between the first sub-chamber 5a and the second sub-chamber 5b is established via through openings 108 provided in a base 107 arranged like a flange around the hollow cylinder 106. The hollow cylinder 106 thus provides a radial separation between gas and liquid in the compensation chamber 5.

[0075] Figure 6 shows a gas injector 1 according to a fifth embodiment of the invention. In the fifth embodiment, the anti-mixing device 100 has an intermediate component 101 designed as a hollow cylinder 106. A free end 106a of the hollow cylinder 106 extends into the area of ​​the compensation chamber 5, in which the gas 41 is located. A liquid emerging from the hollow cylinder 106 with high acceleration is deflected and decelerated at the bottom of the compensation chamber 5. The liquid then drips from the bottom of the compensation chamber 5 into the liquid-filled area of ​​the compensation chamber 5 without excessive foam formation. Figure 7 shows a gas injector according to a sixth embodiment of the invention. The sixth embodiment has a hollow cylinder 109 with radial wall passages 109a. The hollow cylinder 109 extends from the damping device 6 to the bottom of the compensation chamber 5.The hollow cylinder 109 again has a chimney-like settling chamber in which the velocity of the liquid is reduced, whereby a further reduction in velocity can be achieved when passing through the wall passages of the hollow cylinder 109. Preferably, additional obstacles, such as steel wool 104 or the like, are provided in the chimney-like settling chamber of the hollow cylinder 109, or the hollow cylinder is made of a porous material.

[0076] In the seventh exemplary embodiment shown in Figure 8, the gas injector 1 has an anti-mixing device 100 which has two different inner diameters at the compensation chamber 5. A first inner diameter D1 is provided which defines the area in the compensation chamber 5 in which the liquid 40 is arranged. A second inner diameter D2 is the area in the compensation chamber 5 in which the gas 41 is located. The second diameter D2 is larger than the first diameter D1, preferably by a factor of 1.5 or larger. The gas bubble is therefore located in an area with a large radial installation space. The gas bubble is at a sufficient distance from the throttle of the damping device 6 so that liquid supplied at high speed can be slowed down by the liquid in the compensation chamber 5.

[0077] Figures 9 and 10 show a gas injector according to an eighth embodiment of the invention, wherein Figure 9 illustrates a vertical installation position and Figure 10 illustrates an angled installation position at an angle of approximately 45°. The anti-mixing device 100 comprises a tubular device 110. The tubular device 110 is designed as a hollow cylinder and arranged along a central axis of the gas injector. A base of the tubular device 110 is slightly conical. The tubular device 110 ends, as shown in the vertical arrangement in Figure 9, within the liquid region in the compensation chamber 5. An inner diameter of the tubular device 110 is significantly larger than an inner diameter of the throttle. This results in an initial calming of liquid entering at high velocity in the tubular device 110.The axial length of the tubular device 110 is selected such that, in every installation position, a free end of the tubular device 110 lies in the liquid area. This is schematically illustrated in Figure 10, which shows an angled installation position with an angle of approximately 45°. A free end of the tubular device 110 is still below the dividing line 43 (liquid surface) between gas 41 and liquid 40.

[0078] Figures 11 and 12 show a ninth exemplary embodiment of the invention, which is similar to the eighth exemplary embodiment. Figure 11 shows a vertical installation position of the gas injector, and Figure 12 shows an angled installation position with an angle of approximately 45°. In contrast to the eighth exemplary embodiment, in the ninth exemplary embodiment, the tubular device 110 is provided such that an outlet region 110a is provided laterally on the tubular device 110. As a result, the tubular device 110 has a deflection, in particular a deflection of 90° onto an inner jacket region of the compensation chamber 5, thus enabling further flow calming in the tubular device 110. This further reduces the risk of foam formation during operation.

[0079] Figure 13 shows a gas injector with an anti-mixing device 100 according to a tenth embodiment of the invention. The anti-mixing device 100 comprises a valve 111. The valve 111 comprises a ball 112, which seals against a sealing seat 113. The ball 112 is arranged with clearance 114 in a housing 115 of the valve 111. The valve 111 is pressure-controlled and opens during the closing process of the gas injector. Lateral openings are provided in the housing 115 so that the fluid can flow from the valve 111 into the compensation chamber 5.

[0080] Figure 14 shows a gas injector according to an eleventh embodiment of the invention. The gas injector of the eleventh embodiment has an anti-mixing device 100 with a membrane 116. The membrane 116 ensures a fluid-tight seal between the liquid-filled region and the gas-filled region in the compensation chamber 5. Thus, the anti-mixing device 100 of the eleventh embodiment is designed to prevent direct fluid communication between the gas 41 and the liquid 40. This reliably prevents foam formation. Figure 15 shows a gas injector with an anti-mixing device 100 according to a twelfth embodiment of the invention. The anti-mixing device 100 comprises an elastomer 120 with enclosed gas bubbles 41. This makes it possible for temperature-related volume changes of the liquid 40 to be easily compensated for by the elastomer 120 through deformation.The anti-mixing device 10 of the twelfth embodiment thus again ensures complete fluid separation between gas and liquid in the lubricant chamber. It should be noted that instead of enclosed gas bubbles, a type of porous, flexible sponge or the like can also be provided in the elastomer material, so that a connection between gas and liquid is theoretically possible. Upon expansion of the liquid, liquid can then also penetrate the sponge-like elastomer 120.

[0081] Figure 16 shows a gas injector 1 according to a thirteenth embodiment of the invention. The gas injector 1 comprises an anti-mixing device 100, which includes a piston assembly 130. The piston assembly 130 comprises a piston 131 axially preloaded by a spring 132. The piston 131 provides complete separation between the liquid 40 and the gas 41. Upon temperature-related expansion of the liquid 40, the piston 131 is moved in the axial direction XX. Upon cooling, the spring 132 then resets. Thus, the thirteenth embodiment also shows an anti-mixing device that provides complete fluid separation between gas and liquid.

[0082] With regard to all embodiments, it should be noted that it is also possible that any combination of the illustrated embodiments will be obvious to a person skilled in the art.

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 (31) and an armature bolt (24), wherein the valve needle (31) opens and closes a gas path (14) at a sealing seat (11) arranged at a first end of the gas injector, wherein the armature (20) is connected to the armature bolt (24) and the armature bolt (24) is operatively connected to the valve needle (31), - a closed lubricant chamber (4) which is filled with a liquid (40) as lubricant and a gas (41), and in which the armature (20) and the armature bolt (24) are arranged, wherein the lubricant provides a lubricating effect in the lubricant chamber (4), - a return element (10) which returns the closing element (3) to the closed initial position, - a damping device (6) arranged in the lubricant chamber (4), wherein the damping device (6) is designed to dampen a closing movement of the closing element (3), - a compensation chamber (5), which is part of the lubricant chamber (4) and in which liquid (40) and gas (41) are arranged, and - an anti-mixing device (100) which is arranged in the compensation chamber (5) and is designed to prevent mixing of liquid (40) and gas (41) in order to prevent foam formation in the compensation chamber (5).

2. Gas injector according to claim 1, wherein the anti-mixing device (100) enables direct fluid communication between the liquid (40) and the gas (41) in the compensation chamber (5).

3. Gas injector according to claim 2, wherein the anti-mixing device (100) comprises an intermediate component (101) which is arranged in the compensation chamber (5) wherein the intermediate component (101) has at least one connecting opening and divides the compensation chamber (5) into a first sub-chamber (5a) and a second sub-chamber (5b), wherein the intermediate component (101) is completely covered with liquid (40).

4. Gas injector according to claim 2, wherein the anti-mixing device (100) has an intermediate component (101) which is arranged in the compensation chamber (5), wherein the intermediate component (101) divides the compensation chamber (5) into a first sub-chamber (5a) and a second sub-chamber (5b), wherein the intermediate component (101) comprises a plurality of capillary connecting bores (103) which connect the first sub-chamber (5a) to the second sub-chamber (5b).

5. Gas injector according to claim 2, wherein the anti-mixing device (100) comprises an intermediate component (101) which is arranged in the compensation chamber (5), wherein the intermediate component (101) divides the compensation chamber (5) into a first sub-chamber (5a) and a second sub-chamber (5b), wherein the intermediate component (101) has continuous connecting paths and is designed in particular as a porous component and / or as a sieve mesh and / or as a region comprising steel wool.

6. Gas injector according to claim 2, wherein the anti-mixing device (100) comprises an intermediate component (101) arranged in the compensation chamber (5), wherein the intermediate component (101) has a component with a chimney-like calming chamber (105) for calming the flow of the liquid supplied from the damping device (6), wherein a fluid connection is present between the calming chamber (105) and the compensation chamber (5) or there is no fluid connection between the calming chamber (105) and the compensation chamber (5).

7. Gas injector according to claim 6, wherein the chimney-like calming chamber (105) is formed in a hollow cylindrical component.

8. Gas injector according to claim 2, wherein the anti-mixing device (100) is integrated into the compensation chamber (5), wherein the compensation chamber (5) has a region filled with gas (41) and a region filled with liquid (40), wherein a first inner diameter (D1) in the region filled with liquid (40) filled area is smaller than a second inner diameter (D2) in the area filled with gas (41).

9. Gas injector according to claim 2, wherein the anti-mixing device (100) comprises a tubular device (110), in particular a hollow cylinder which is arranged in the central axis of the gas injector or a bent tube with a lateral opening, wherein the tubular device (110) protrudes into the compensation chamber (5) and a free end of the tubular device (110) is covered with liquid.

10. Gas injector according to claim 2, wherein the anti-mixing device (100) comprises an intermediate component (110) which is arranged in the compensation chamber (5), wherein the intermediate component (110) comprises a pressure-controlled valve (111) which is designed to close a fluid connection between the compensation chamber (5) and the damping device (6) during an opening process of the gas injector and to open it during a closing process of the gas injector.

11. Gas injector according to claim 10, wherein the pressure-controlled valve is a ball valve with a limitedly freely movable ball, wherein the ball closes the valve at a sealing seat during the opening process of the gas injector.

12. Gas injector according to claim 1, wherein the anti-mixing device (100) prevents direct fluid communication between the gas (41) and the liquid (40).

13. Gas injector according to claim 12, wherein the anti-mixing device (100) is a flexible element arranged in the compensation chamber (5), in particular a flexible membrane or an elastomer element filled with gas (41).

14. Gas injector according to claim 12, wherein the anti-mixing device (100) comprises a piston assembly (130) with a movable piston (131), wherein the movable piston (131) separates the liquid (40) and the gas (41) in a fluid-tight manner.

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