Gas injector

Abstract

The present invention relates to a gas injector for injecting a gaseous fuel, comprising a magnetic actuator with an armature, an inner pole and a coil, a closing element with a valve needle and an armature pin, wherein the valve needle opens and closes a gas path at a sealing seat arranged at a first end of the gas injector, wherein the armature is connected to the armature pin and the armature pin is in operative communication with the valve needle, a sealed lubrication chamber filled with a liquid as a lubricant and a gas, in which the armature and the armature pin are arranged, wherein the lubricant provides a lubricating effect in the lubrication chamber, a reset element which returns the closing element to the closed initial position, a damping device which is arranged in the lubrication chamber, wherein the damping device is configuredto dampen a closing movement of the closing element, and a compensation chamber which is part of the lubricant chamber and in which liquid and gas are arranged, wherein the compensation chamber has an eccentric area which is arranged eccentrically to a central axis of the gas injector.

Description

State of the art

[0001] 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 very safe operating behavior.

[0002] Gas injectors are known in various designs from the prior art. Due to the relatively high gas pressures, a hard impact of a closing element, especially a valve needle, against a sealing seat occurs, particularly during the closing process. To avoid unnecessarily shortening the service life of the gas injector, damping devices should be provided. To avoid unnecessarily increasing manufacturing and maintenance costs, simple solutions are preferable. Disclosure of the invention

[0003] In contrast, 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 during the closing process of the gas injector is possible. This damping is ensured throughout the entire service life of the gas injector. The damping is also particularly 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 also prevents vibration excitation of other components of the gas injector during the closing process, so that the loads on these other components during operation can be significantly reduced. Furthermore, the measures according to the invention prevent foaming processes inside a lubricant chamber containing a liquid and a gas.This ensures a 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, in particular horizontally. Thus, the gas injector according to the invention is suitable for use in internal combustion engines from various manufacturers, where the installation position may deviate slightly, especially from a vertical axis.

[0004] According to the invention, this is achieved by the gas injector comprising a magnetic actuator with an armature, an inner pole, and a coil. Furthermore, the gas injector includes 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. This allows gas to be injected, for example, into a combustion chamber or terminates the injection. The closing element also includes an armature pin, which is connected to the armature and is operatively connected to the valve needle. The valve needle and the armature pin are preferably rod-like components that rest loosely against each other at opposite end faces and are movable independently of each other. The gas injector further includes a lubricant chamber, enclosed by a lubricant housing, which is filled with a liquid lubricant and a gas.The anchor and anchor bolt are arranged in the lubricant chamber, with the lubricant providing lubrication for the components located therein. A return element returns the closing element to a closed initial position. The lubricant chamber is preferably designed as a sealed chamber by means of a flexible sealing element, in particular a bellows, the flexible sealing element being arranged on the closing element. The flexible sealing element seals the lubricant chamber against the injected gas via a gas path. Furthermore, the gas injector includes a damping device for dampening the closing action of the closing element, which is arranged in the lubricant chamber. The gas injector also includes a compensation chamber in which the liquid and the gas are arranged.The partially gas-filled lubricant chamber thus allows for simple volume expansion, particularly in the event of temperature-related volume changes in components and / or the fluid during operation. The compensation chamber is a sub-chamber of the lubricant chamber. This compensation chamber has an eccentric section. Due to this eccentric section, a portion of the compensation chamber protrudes on one side relative to other areas of the lubricant chamber, extending from the central axis of the gas injector. As a result, gas present in the lubricant chamber collects in the eccentric section when this protruding portion is oriented upwards in the installed position within an internal combustion engine.This allows for extreme tilt angles of 90° and more, for example for construction machinery, to be achieved for the installation position of the gas injector without negatively impacting the reliability and stability of the gas injector's damping function. This further extends the service life of the gas injector under extreme stress and, in particular, reduces wear on the sealing seat and / or the magnetic actuator and other components.

[0005] The compensation chamber is preferably located at the end of the gas injector furthest from the sealing seat. If the gas injector is installed vertically or substantially vertically, the gas in the lubricant chamber collects in the compensation chamber at the end furthest from the lubricant chamber. If extreme tilting of the internal combustion engine and the gas injector occurs during operation, the gas collects in the eccentric area of ​​the compensation chamber. This prevents the mixing of gas and liquid, which could lead to foaming or the introduction of gas bubbles into the liquid, even in extreme situations. Foaming must be avoided, in particular, to prevent gas droplets from entering the damping device and reducing the damping properties of the gas injector. This would shorten the service life of the gas injector.

[0006] According to the invention, a separation between liquid and gas in the lubricant chamber can be achieved, even during operation. This makes the gas injector particularly suitable for installation at angles deviating from the vertical. Depending on the internal combustion engine from a particular manufacturer, the gas injector cannot always be installed in a perfectly vertical position. The gas injector according to the invention thus offers increased flexibility regarding installation positions and provides very robust and stable operation throughout its entire service life.

[0007] The dependent claims describe preferred embodiments of the invention.

[0008] Preferably, the compensation chamber is designed to be completely eccentric. This allows for a large gas reservoir to be provided in the aforementioned eccentric area of ​​the compensation chamber.

[0009] Alternatively, the compensation chamber is designed such that it has a concentric and an eccentric region. This facilitates the connection of the compensation chamber to the damping device and, preferably, allows a calming zone to be introduced in the concentric region of the compensation chamber to at least partially dampen fluid movements during operation of the gas injector.

[0010] The eccentric region of the compensation chamber is preferably arranged at an end of the compensation chamber furthest from the sealing seat. The concentric region is thus located adjacent to the damping device.

[0011] Preferably, the compensation chamber includes a connecting channel that links the eccentric area to a bypass bore in the damping device. This allows for an increase in the gas volume of the lubricant chamber in cases of extreme installation positions of the gas injector or large inclinations occurring during operation. This ensures, in particular, that the gas bubble in the lubricant chamber is as far away as possible from a throttle in the damping device.

[0012] Preferably, the gas injector includes an anti-mixing device (separator) arranged in the compensation chamber and designed to prevent the mixing of liquid and gas within the chamber. This prevents foaming, which could negatively affect the function of the gas injector.

[0013] Preferably, the compensation chamber includes a settling chamber in the concentric area. Preferably, the anti-mixing device is also arranged in the settling chamber.

[0014] The anti-mixing device is preferably made of metal. Alternatively, the housing of the equalization chamber can be made of plastic. The anti-mixing device itself can also be made of plastic, preferably as an injection-molded component, or alternatively, a metallic insert can be incorporated as the anti-mixing device during the injection molding process. For cost reasons, the anti-mixing device can, for example, be manufactured as a stamped part.

[0015] The lubricant chamber is enclosed by the lubricant housing, which preferably comprises a plurality of components. The ratio of liquid, i.e., liquid lubricant, to gas in the lubricant chamber is preferably in the range of 70 / 30 vol.% to 95 / 5 vol.%. Particularly preferably, the liquid-to-gas ratio is in the range of 80 / 20 vol.% to 90 / 10 vol.%. Further preferably, the liquid-to-gas ratio in the lubricant chamber is approximately 85 to 15 vol.%.

[0016] The damping device preferably comprises a damping piston, a damping housing, a throttle, and a damping chamber formed within the damping housing. The throttle connects the damping chamber to the compensation chamber. A guide section is formed between the damping piston and the damping housing. This guides the damping piston within the damping housing. The guidance preferably extends over the entire axial length of the damping piston. The clearance between the damping piston and the damping housing is very small. The throttle is preferably located along the 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 velocities are slowed down by the anti-mixing device according to the invention to prevent foaming.

[0017] Preferably, the throttle of the damping device is designed such that the throttle length in the axial direction of the gas injector is less than or equal to the throttle diameter. By selecting the throttle length and / or diameter, the throttle characteristics can thus be easily adjusted. In particular, this allows the flow rates of the liquid through the throttle to be adjusted, thereby setting the damping characteristics.

[0018] The damping chamber is preferably pot-shaped, and the choke is located at the bottom of the pot-shaped damping chamber. This allows for a particularly compact and simple design.

[0019] The gas injector is preferably configured for the direct injection of gas into the combustion chamber of an internal combustion engine or for intake manifold injection. The gas injector is preferably an outwardly opening gas injector. Brief description of the drawings

[0020] A preferred embodiment of the invention is described in detail below with reference to the accompanying drawing. The drawing shows: Fig. 1 a schematic sectional view of a gas injector according to a preferred embodiment of the invention, and Fig. 2 an enlarged partial sectional view of a damping device and a compensation chamber of the gas injector of Fig. 1. Preferred embodiment of the invention

[0021] The following refers to the Fig. 1 and Fig. 2 a gas injector 1 according to a preferred embodiment of the invention is described in detail.

[0022] Fig. Figure 1 shows the closed state of gas injector 1.

[0023] As from Fig. As can be seen in 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 moves a closing element 3, which in this embodiment is an outwardly opening valve needle, from a closed state to an open state.

[0024] The magnetic actuator 2 comprises an armature 20, which rests against the closing element 3 by means of an armature bolt 24. Furthermore, the magnetic actuator 2 comprises an inner pole 21, a coil 22, and a magnetic housing 23, which ensures a magnetic return of the magnetic actuator.

[0025] The gas injector 1 further comprises a main body 7 with a connection area 70, through which the gaseous fuel is supplied into an inner region 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.

[0026] The closing element 3 opens or closes a passage at the sealing seat 11 for the injection of the gaseous fuel.

[0027] In Fig. Figure 1 schematically shows an electrical connection 13, which is led through the main body 7 to the magnetic actuator 2.

[0028] The locking element 3 is inserted into the Fig. 1. The closed position shown is a return from the open position. Fig. Figure 1 schematically indicates a gas path 14 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.

[0029] The gas injector 1 further comprises a sealed lubricant chamber 4, which is filled with a liquid 40 as a lubricant, preferably oil, and a gas 41, preferably air. As shown from Fig. As can be seen in Figure 1, the lubricant chamber 4 is defined 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 located at the end of the lubricant chamber 4 furthest from the sealing seat 11.

[0030] The gas injector 1 is shown in a horizontal installation position. The axial direction XX is aligned horizontally. In the Fig. 1 and Fig. 2 is a schematic representation of a dividing line 43 between gas 41 and liquid 40.

[0031] Most of the lubricant chamber 4 is filled with the liquid lubricant.

[0032] This ensures, in particular, lubrication of the armature 20 during operation. The return element 10 is also located in the lubricant chamber.

[0033] 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 from the sealing seat towards the armature 20.

[0034] The damping device 6 is described in detail on Fig. 2 is evident.

[0035] 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.

[0036] The damping piston 61 is cylindrical and has a through-opening 64 which runs in a central axis of the gas injector.

[0037] The damping device 6 further comprises a return element 65 for returning the damping piston 61 to its position. Fig. 2 Starting positions shown.

[0038] As from Fig. As can be seen in Figure 2, the end face 24a of the anchor bolt 24, facing away from the sealing seat, is in direct contact with an end face 61b of the damping piston 61. The anchor bolt 24 is guided in a stationary guide component 25. In the closed state of the gas injector, a gap 26 exists between the end face of the damping piston 61 facing the sealing seat and the guide component 25. The return element 65 is pre-tensioned and is supported between a flange 61a of the damping piston 61 and the damping housing 60.

[0039] The gas injector 1 further comprises an anti-mixing device 100. The anti-mixing device 100 is arranged in the compensation chamber 5.

[0040] The anti-mixing device 100 comprises an intermediate component 101 with several connecting openings 102. The connecting openings 102 serve for fluid connection in the compensation chamber 5. The connecting openings 102 are preferably small bores.

[0041] The anti-mixing device 100 is designed to prevent the 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 significant risk to the function of the gas injector and especially 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 may be damaged by a strong impact on the sealing seat 11.

[0042] It should be noted that the compensation chamber 5 may have a plastic housing. Preferably, the entire compensation chamber 5 is an injection-molded plastic component. It is also possible that the anti-mixing device 100 is a metallic insert and can be fixed in the compensation chamber 5 during the injection molding process. A filling opening for the lubricant chamber 4 may also be provided in the compensation chamber 5.

[0043] As from Fig. As can be seen in Figure 2, the compensation chamber 5 has an eccentric region 53 and a concentric region 54. The eccentric region 53 is located at the end of the compensation chamber 5 furthest from the sealing seat 11. The concentric region 54 is arranged in the axial direction XX between the eccentric region 53 and the damping device 6.

[0044] The concentric section 54 has a settling chamber 5a, which is located immediately downstream of the throttle 62. The settling chamber 5a serves to calm the fluid that flows into it from the throttle 62 during the damping process. This provides a first measure to calm the flow from the damping device 6 into the equalization chamber 5. A further measure to reduce the fluid velocity is then ensured by the anti-mixing device 100.

[0045] The compensation chamber 5 also has a connecting channel 55, which connects the eccentric area 53 with a bypass bore 67 in the damping housing 60. As shown from Fig. As can be seen in Figure 2, this increases the area in which gas 41 is present when the gas injector is arranged horizontally. The connecting channel 55 is also connected to the settling chamber 5a via a connection 56. This prevents a gas bubble from becoming trapped in the settling chamber 5a, which could lead to foam formation there.

[0046] The eccentric shape of the compensation chamber thus allows the liquid level to rise, so that the dividing line 43 between gas 41 and liquid 40 is higher. This allows, in particular, a greater distance between the liquid surface and the throttle 62 to be achieved. Since the flow of liquid exiting the throttle 62 can be generated in pulses, the more liquid is present in the area of ​​the throttle 62's outflow, the more the liquid flow velocity can be reduced. This reduces the risk of liquid and gas mixing in the compensation chamber 5. Therefore, even extreme installation positions, such as those found in the Fig. 1 and Fig. 2 shown in a horizontal installation position, which is made possible by the gas injector according to the invention without damage to the gas injector.

[0047] 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 rigidly connected to the armature bolt 24, towards the inner pole 21. Since the armature bolt 24 is in direct contact with the closing element 3, this lifts the closing element 3 from the sealing seat 11, allowing gas to be injected into the combustion chamber 30.

[0048] In the damping device 6, the spring force of the return element 65 moves the damping piston 61 towards the guide component 25, which in Fig. 2 is indicated by arrow A. This overcomes the gap 26 and increases the volume of the damping chamber 63. Lubricant can flow into the damping chamber 63 either through the throttle 62 or through the through-opening 64.

[0049] When the gas injector closes, the current to the magnetic actuator 2 is terminated, causing the reset element 10 to return the closing element 3 and the armature bolt 24 to their closed positions. In doing so, the armature bolt 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.

[0050] Since there is only a very narrow guide gap 6a between the damping piston 61 and the damping housing 60 at a guide area 66, the damping piston 60 must be reset by displacing this fluid from the damping chamber 63. Because the guide gap 6a is very narrow in the guide area 66, this displacement occurs essentially exclusively via the throttle 62 into the compensation chamber 5.

[0051] Thus, fluid exits the throttle 62 at high speed into the first sub-chamber 5a of the compensation chamber 5, which in Fig. 2 is represented by the arrows B. Without the anti-mixing device, a very strong flow would therefore be generated at the liquid surface in the compensation chamber 5 due to liquid entering at high speed, which could lead to foaming.

[0052] The anti-mixing device 100 according to the invention, with the intermediate component 101 in the compensation chamber 5 and the settling chamber 5a, prevents a direct inflow of the accelerated liquid. The accelerated liquid strikes the inner surface 101a of the intermediate component 100 and is significantly slowed down. Since the connecting openings 102 have very small diameters, it is prevented that rapidly flowing liquid enters the second sub-chamber 5b of the compensation chamber 5. Furthermore, the gas in the compensation chamber 5 is located mainly in the eccentric region 53. This allows for maximum distance between the gas and the throttle 62. As a result, the formation of foam during operation is prevented. Therefore, 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.

[0053] There, as in Fig.As shown in Figure 2, gas may also be present in the settling chamber 5a; this is forced into the connecting channel 55 via the connection 56 when liquid flows into the settling chamber 5a through the throttle 62.

[0054] Since the dimensions of the throttle 62 can be manufactured very precisely, in addition to precise damping of the closing element 3 via the anchor bolt and the damping piston 61, it is also possible to adjust the velocity of the fluid exiting the throttle. In particular, throttling is independent of the axial length of the guide section 66 between the damping piston 61 and the damping housing 60.

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 anchor bolt (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 anchor (20) is connected to the anchor bolt (24) and the anchor bolt (24) is in operative communication with the valve needle (31), - a closed lubricant chamber (4) which is filled with a liquid (40) as a lubricant and a gas (41), and in which the anchor (20) and the anchor bolt (24) are arranged, wherein the lubricant provides a lubricating effect in the lubricant chamber (4), - a reset element (10) which returns the closing element (3) to the closed starting position, - a damping device (6) which is arranged in the lubricant chamber (4), wherein the damping device (6) is configured to dampen a closing movement of the closing element (3), and - a compensation chamber (5) which is part of the lubricant chamber (4) and in which liquid (40) and gas (41) are arranged, - wherein the compensation space (5) has an eccentric area (53) which is arranged eccentrically to a central axis of the gas injector. [2] Gas injector according to claim 1, wherein the compensation chamber (5) is arranged completely eccentrically to the central axis of the gas injector. [3] Gas injector according to claim 1, wherein the compensation space (5) has a concentric region to the central axis of the gas injector and an eccentric region to the central axis of the gas injector. [4] Gas injector according to claim 3, wherein the eccentric region of the compensation chamber (5) is arranged at the end of the compensation chamber (5) facing away from the sealing seat (11). [5] Gas injector according to one of the preceding claims, wherein the compensation chamber (5) has a connecting channel (55) which connects the eccentric area (53) to a bypass bore (67) in the damping device (6). [6] Gas injector according to one of the preceding claims, further comprising an anti-mixing device (100) which is arranged in the compensation chamber (5) and is configured to prevent mixing of liquid (40) and gas (41) in order to prevent foam formation in the compensation chamber (5). [7] Gas injector according to one of claims 3 to 6, further comprising a settling chamber (5a) which is arranged in the concentric region of the equalization chamber (5). [8] Gas injector according to claim 6 or 7, wherein the anti-mixing device (100) is made of metal. [9] Gas injector according to one of the preceding claims, wherein a housing of the compensation chamber (5) is made of plastic.

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