Gas injector

Abstract

The present invention relates to a gas injector comprising a magnetic actuator, 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 lubricant chamber filled with a liquid as lubricant and a gas, in which the armature and the armature pin are arranged, a reset element which returns the closing element to the closed initial position, a damping device which is arranged in the lubricant chamber, wherein the damping device is configured to dampen a closing movement of the closing element, a compensation chamber,which is part of the lubricant chamber and in which liquid and gas are arranged, wherein the damping device has a damping chamber, wherein the damping chamber is fluidly connected to the compensation chamber via a throttle, and wherein the throttle is arranged off-center from a central axis XX 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] The gas injector according to the invention for injecting a gaseous medium, 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. In particular, the damping is 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 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, 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.This ensures a very stable function of the gas injector. Therefore, 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.

[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. During operation, the gas contained in the lubricant chamber is located in the compensation chamber of the gas injector. The damping device comprises a damping chamber with a base and a damping piston, which is arranged within the damping chamber. The damping chamber is fluidly connected to the compensation chamber via a throttle. The throttle is positioned off-center on the central axis of the gas injector. This allows for any installation position of the gas injector, particularly at an angle between 0° and 90° from the central axis of the gas injector, without the risk of gas entering the damping chamber when refilling it with fluid.If gas is present in the damping chamber, the damping performance of the gas injector may be significantly impaired. In extreme cases, the damping function could fail completely. The off-center arrangement of the throttle ensures that, regardless of the installation position, even when the gas injector is mounted at an angle, the throttle is always covered with liquid, thus preventing gas from entering the damping chamber of the damping device.

[0005] This allows the damper volume to be refilled completely without any gas entering the damping chamber. The off-center placement of the throttle, through which the damping chamber is refilled, is thus positioned at a greater distance from any gas bubble in the compensation chamber, thereby reducing the risk of gas entering the damping chamber.

[0006] The dependent claims describe preferred embodiments of the invention.

[0007] Preferably, the throttle is arranged in a base of the damping chamber, the base being directed towards the compensation chamber.

[0008] Alternatively or additionally, the throttle is located in a wall area of ​​the damping chamber. The throttle in the wall area is positioned as close as possible to the bottom of the damping chamber to prevent it from being closed by the movement of a damping piston.

[0009] Preferably, the gas injector has an installation position with an angle to a central axis XX of the gas injector in a range between 0° ≤ a ≤ 90°.

[0010] Preferably, the lubricant chamber contains approximately 80% liquid and 20% gas by volume at an ambient temperature of 20°C. Preferably, the proportion of gas is reduced when the gas injector's installation position is rotated towards 90°.

[0011] Preferably, the damping piston has a through-hole which is arranged centrally in the central axis XX of the gas injector. This improves the damping dynamics of the damping device.

[0012] Preferably, the gas injector includes an anti-mixing device located in the compensation chamber. This device is designed to prevent the mixing of liquid and gas, thereby preventing foam formation in the compensation chamber. This measure also reduces the risk of gas entering the damping chamber.

[0013] 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.

[0014] 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 further preferably an outwardly opening gas injector. Brief description of the drawings

[0015] Preferred embodiments of the invention are 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 first preferred embodiment of the invention in a vertical installation position, Fig. 2 an enlarged partial sectional view of a damping device and a compensation chamber of the gas injector of Fig. 1, Fig. 3 a partial sectional view of the gas injector of Fig. 1 in an installation position deviating from the vertical, and Fig. 4 a partial sectional view of a gas injector according to a second embodiment of the invention. Preferred embodiments of the invention

[0016] The following refers to the Fig. 1 to 3 a gas injector 1 according to a first preferred embodiment of the invention is described in detail.

[0017] Fig. Figure 1 shows the closed state of gas injector 1.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] The closing element 3 opens or closes a passage for the injection of gaseous fuel at the sealing seat 11.

[0022] In Fig. Figure 1 schematically shows an electrical connection 13, which is led through the main body 7 to the magnetic actuator 2.

[0023] 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.

[0024] 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.

[0025] Gas injector 1 is in the Fig. 1 and Fig. Figure 2 shows the gas injector in a vertical installation position. A central axis XX of the gas injector is vertically oriented. This ensures that the gas 41 collects in the upper area of ​​the compensation chamber 5. Fig. 1 and Fig. 2 is a schematic representation of a dividing line 43 between gas 41 and liquid 40.

[0026] Most of the lubricant chamber 4 is filled with the liquid lubricant.

[0027] This ensures, in particular, lubrication of the armature 20 during operation. The return element 10 is also located in the lubricant chamber.

[0028] 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 11 towards the armature 20.

[0029] The damping device 6 is described in detail on Fig. 2 is evident.

[0030] 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 a bottom 63a, wherein the damping piston 61 is partially arranged in the damping chamber.

[0031] The damping piston 61 is cylindrical and has a through-opening 64 which runs in the central axis XX of the gas injector.

[0032] The damping device 6 further comprises a return element 65 for returning the damping piston 61 to its position. Fig. 2 Starting positions shown.

[0033] 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.

[0034] 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 subchamber 5a and a second subchamber 5b. The first subchamber 5a is completely filled with liquid, and the second subchamber 5b is partially filled with liquid and partially with gas.

[0035] The anti-mixing device 100 comprises an intermediate component 101 with several connecting openings 102. The connecting openings 102 serve for fluid connection between the first sub-chamber 5a and the second sub-chamber 5b. The connecting openings 102 are preferably small bores.

[0036] As especially from Fig. As can be seen in Figure 2, the intermediate component 101 is thus covered with liquid on both an inner surface 101a and an outer surface 101b. In other words, the intermediate component 101 is completely immersed in the liquid in the lubricant chamber 4.

[0037] 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.

[0038] What's next? Fig. As can be seen in Figure 2, the throttle 62 is located in the base 63a of the damping chamber 63. The throttle 62 provides a fluid connection between the damping chamber 63 and the compensation chamber 5. The throttle 62 is located off-center from the central axis XX of the gas injector.

[0039] In a situation like the one in the Fig. 1 and Fig. In the vertical installation position of the gas injector shown in Figure 2, there is always a sufficient amount of liquid above the throttle 62, so that during refilling (arrow B in Figure 2) Fig. 2) of the damping chamber 63 with liquid 40 through the throttle 62 there is no danger that a gas may enter the damping chamber 63.

[0040] In a situation like in Fig. In the installation position of the gas injector shown in Figure 3, which deviates by 90° from a vertical YY, there could be a risk of gas entering the damping chamber 63 if the throttle is arranged centrally on the central axis XX of the gas injector. This is prevented by the inventive idea of ​​arranging the throttle 62 off-center from the central axis XX in the base 63a. Naturally, the injector is installed such that the throttle 62 is positioned correctly in a 90° installation position, as shown in Figure 3. Fig. Figure 3 shows that it lies below the central axis XX. This also ensures that no gas can enter the damping chamber 63 when it is refilled.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] Thus, liquid from the throttle 62 enters the first sub-chamber 5a of the compensation chamber 5 at high speed. Without the anti-mixing device, a very strong flow would therefore be generated at the liquid surface in the compensation chamber 5 due to the high-speed inflow of liquid, which could lead to foaming.

[0046] The anti-mixing device 100 with the intermediate component 101 in the compensation chamber 5 prevents a direct flow of the accelerated liquid. The accelerated liquid strikes the inner surface 101a of the intermediate component 101 and is significantly slowed down. Since the connecting openings 102 have very small diameters, this prevents rapidly flowing liquid from entering the second sub-chamber 5b of the compensation chamber 5. This prevents the formation of foam during operation. Consequently, 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.

[0047] Thus, in particular, the combination of the anti-mixing device 100 with the off-center arrangement of the throttle 62 prevents the introduction of gas or gas bubbles into the damping chamber 63.

[0048] 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.

[0049] A further embodiment of the invention is described in detail below, wherein identical components are designated with the same reference numerals as in the first embodiment.

[0050] Fig. Figure 4 shows a gas injector according to a second embodiment of the invention. The gas injector again has an installation position with an angle a = 90° to a vertical YY. In contrast to the previous embodiment, in the second embodiment the throttle 62 is arranged in a wall region 63b of the damping chamber 63. As shown in Figure 4, the throttle 62 is arranged in a wall region 63b of the damping chamber 63. Fig. As can be seen in Figure 4, the throttle 62 is arranged as close as possible to the level of the bottom 63a of the damping chamber 63 in order to prevent the damping piston 61 from closing the throttle. This embodiment ensures further improved safety against the introduction of gas or gas bubbles during operation. The gas injector 1 is arranged at a 90° angle to the vertical YY such that the throttle 62 lies below the central axis XX.

Claims

[1] Gas injector for injecting a gaseous medium, 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), - a compensation chamber (5) which is part of the lubricant chamber (4) and in which liquid (40) and gas (41) are arranged, - wherein the damping device (6) has a damping chamber (63) with a bottom (63a) and a damping piston (61), - wherein the damping piston (61) is arranged in the damping chamber (63), - wherein the damping chamber (63) is fluidly connected to the compensation chamber (5) via a throttle (62), and - wherein the throttle (62) is arranged off-center on a central axis XX of the gas injector. [2] Gas injector according to claim 1, wherein the throttle (62) is arranged in the bottom (63a) of the damping chamber (63), the bottom (63a) being directed towards the compensation chamber (5). [3] Gas injector according to one of the preceding claims, wherein the throttle (62) is arranged in a wall region (63b) of the damping chamber (63). [4] Gas injector according to one of the preceding claims, wherein the gas injector has an installation position at an angle a between 0° ≤ a ≤ 90°. [5] Gas injector according to one of the preceding claims, wherein the lubricant chamber contains approximately 80 vol% liquid and approximately 20 vol% gas at an ambient temperature of 20°C. [6] Gas injector according to one of the preceding claims, wherein the damping piston (61) has a through-opening (64) which is located centrally in the central axis XX of the gas injector. [7] 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).

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