Gas injector equipped with a hydraulic damping device with free stroke

Abstract

The invention relates to a gas injector for injecting a gaseous medium, comprising a closure element (2) for opening and closing a through opening (4) in a sealing seat (3), a return element (6) for returning the closure element (2) to its closed initial position, an actuator (5) for operating the closure element (2), a hydraulic damping device (7) for damping the movement of the closure element (2), the hydraulic damping device (7) being adjusted to provide damping by means of a liquid in a closed hydraulic chamber (8), and a free stroke assembly (20) arranged between the closure element (2) and the hydraulic damping device (7) and adjusted to effect damping of the movement of the closure element (2) only after it has traveled a predefined free stroke (S1).

Description

Technical Field

[0001] Background Art The present invention relates to a gas injector for injecting a gaseous medium, particularly hydrogen or noble gas or the like, with a hydraulic damping device having a free stroke in order to damp the movement of a valve needle, particularly in both the opening process and the closing process.

[0002] Gas injectors are known in various configurations based on the prior art. Depending on the gaseous medium injected by the gas injector, the gas injector has to perform a very large stroke compared to an injector for a liquid medium, for example a fuel injector. However, in a gas injector, this can lead to significant wear and stroke limitations in the components, particularly in the sealing sheet. Based on the large switching forces required in a gas injector, the wear occurring in the components during operation is further amplified.

[0003] Disclosure of the Invention A gas injector according to the present invention, having the features described in claim 1, for injecting a gaseous medium, particularly hydrogen or a noble gas, has the following advantages over conventional injectors: Namely, despite the large stroke due to the large gas volume to be injected, the damping device can be provided in an extremely small and inexpensive manner. This damping device also reduces wear on the components of the gas injector. Furthermore, the gas injector according to the present invention has significantly improved noise characteristics, particularly during impact with the terminal stopper in the opening process and during the closing of the seal sheet in the closing process. This is achieved according to the present invention by the following configuration: Namely, the gas injector has a closing element that opens and closes a through-opening provided in a seal sheet. Furthermore, the gas injector includes a return element that returns the closing element from an open state to an initial closed state. Furthermore, an actuator for operating the closing element and a hydraulic damping device are provided. The hydraulic damping device is tuned to dampen the motion of the closing element. Damping in this case is performed using a liquid, which carries out the damping process within the closed hydraulic chamber of the damping device when the closing element is opening and / or closing. Furthermore, a free stroke assembly is provided, which is functionally positioned between the closing element and the hydraulic damping device. The free stroke assembly is adjusted so that damping of the closing element's motion only occurs after it has advanced a predetermined free stroke, both in the opening and closing processes. This allows for an extremely inexpensive and compact structure for the damping device. Therefore, due to the free stroke of the free stroke assembly, the opening and closing processes are performed first without damping, and the damping device only acts after it has advanced the free stroke. Thus, excessive wear on the contact components of the gas injector, particularly the seal sheet and / or the stopper that limits the opening stroke of the gas injector, can be avoided. Furthermore, based on hydraulic damping using the damping device, significantly improved noise characteristics are obtained during the opening and closing processes of the gas injector.

[0004] The dependent claims describe advantageous improvements to the present invention.

[0005] It is even more advantageous if the complete opening stroke of the closing element includes the free stroke of the free stroke assembly and the damping stroke of the hydraulic damper. In this case, the damping stroke of the hydraulic damper is smaller than the free stroke. Therefore, for example, during the opening process, a correspondingly large amount of air is achieved simultaneously with a very rapid opening, and then the opening motion is damped by the damper after advancing the free stroke, which slightly slows down the opening process. Similarly, during the closing motion of the closing element, the majority of the closing stroke of the closing element is advanced first by advancing the free stroke, and then the hydraulic damper acts to enable damping to avoid wear and noise when the closing element collides with the seal sheet.

[0006] The ratio of the damped stroke to the free stroke is preferably in the range of 0.06 to 0.12, particularly in the range of 0.08 to 0.10, and especially advantageously 0.9.

[0007] It is even more advantageous if the free stroke assembly includes a free stroke housing, a control element disposed within the free stroke housing, and a stopper element, particularly a stopper ring, fixed to the free stroke housing. In this case, the free stroke is formed between the control element and the stopper element, or, in an alternative configuration, between the control element and the free stroke housing. This allows the free stroke assembly to be made extremely compact and small.

[0008] It is even more advantageous if the free-stroke housing is coupled to a hydraulic damper and the control element is coupled to a closing element. In an alternative configuration, the free-stroke housing is coupled to a closing element and the control element is coupled to a hydraulic damper. Thus, the free-stroke assembly is incorporated axially between the closing element and the hydraulic damper of the gas injector.

[0009] It is even more advantageous if the hydraulic damping device includes a base body and a centering pin axially movable within the base body, wherein the centering pin is coupled to a free-stroke assembly. This allows the coupling between the hydraulic damping device and the free-stroke assembly to be easily achieved via the centering pin. The centering pin preferably protrudes into the interior of the hydraulic damping device.

[0010] For the simplest possible structure, the hydraulic damping device has a first control chamber and a second control chamber, both of which are connected to each other via a fluid connection. In this case, two control chambers are provided, one of which is responsible for damping the opening motion of the closing element, and the other is responsible for damping the closing motion of the closing element.

[0011] The fluid connection between the first control chamber and the second control chamber preferably includes a throttling. This throttling is preferably located in a control cylinder that separates the first and second control chambers. Through this throttling, the closing element is damped by the volume change in the first and second control chambers during the opening and closing processes. The throttling may be formed, for example, as a small hole provided in the control cylinder, or it may be provided via a radial gap provided in the control cylinder, either optionally or additionally.

[0012] It is even more advantageous if the first control chamber and the second control chamber are formed within the base body, and in particular in the form of an open hole or similar opening located on one side of the central axis of the gas injector.

[0013] To achieve the most compact structure possible, the damping device preferably comprises a base body, a first flexible element, and a second flexible element. In this case, the closing element is coupled to the first flexible element, and the first and second flexible elements together form a housing region of a closed hydraulic chamber. Thus, the first flexible element allows the movement of the closing element.

[0014] The first and second flexible elements are preferably metal diaphragms. In an alternative configuration, the first and second flexible elements are metal bellows.

[0015] It is even more advantageous if a first flexible element is positioned on the base body of the damping device, and a first subchamber of the hydraulic chamber is formed between the base body and the first flexible element. Furthermore, a second flexible element is positioned on the base body, and a second subchamber of the hydraulic chamber is formed between the base body and the second flexible element. In this case, the first subchamber and the second subchamber are fluidly connected to each other via a connecting region, preferably a groove or hole or similar.

[0016] It is even more advantageous if the first control room and the second control room are connected to the connection area via a lateral opening.

[0017] To minimize the temperature influence on the damping device during operation, the damping device and free stroke assembly are preferably positioned on the side of the actuator opposite the seal sheet, in the axial direction XX of the gas injector. Thus, the actuator protects the damping device and free stroke assembly from thermal influences that may occur, especially when the gas injector is tuned for direct injection into the combustion chamber of an internal combustion engine.

[0018] The gas injector is, more preferably, a gas injector that opens outward. The gas injector is preferably formed to directly inject gaseous fuel into the combustion chamber of an internal combustion engine.

[0019] To provide the most compact, pre-assembled unit possible, the hydraulic damping device is preferably formed as a pre-assembled module together with the free-stroke assembly. The pre-assembled module is preferably located within an operating module housing through which a closing element is guided.

[0020] To avoid large leaks from the first and second control chambers into the hydraulic chamber, the centering pin is preferably guided by a first flexible element, particularly a metal diaphragm, and a sealing disc. In this case, the sealing disc is pre-biased axially by a spring disc. This means that the radial gaps within the damping device can be made extremely small, so that leaks occurring through these radial gaps can be minimized.

[0021] The spring disc is preferably formed in a pot shape and includes a retaining edge, an axially projecting projection, and an axial notch. The spring disc is preferably located in a second control chamber of a hydraulic damping device. Preferably, the spring disc applies an axial force to the seal disc, thereby sealing the seal disc to the base body of the hydraulic damping device.

[0022] In an alternative advantageous configuration, the seal disc described above is pressed against the base body of the hydraulic damper by a press-fitted disc. This allows for an extremely good seal, particularly in the contact area between the seal disc and the base body. In this case, the seal disc, along with a first flexible element, particularly a metal diaphragm, guides the centering pin. Preferably, a radius is formed on the inner circumferential surface of the seal disc. This allows for the formation of an extremely small radial gap, thereby minimizing leakage from the hydraulic chamber to the first and second control chambers through these radial gaps. In this case, the press-fitted disc is bonded to the base body by press bonding.

[0023] Preferably, a compensation chamber filled with liquid is provided on the radially outer circumferential surface of the seal disc.

[0024] Furthermore, the present invention relates to an internal combustion engine equipped with a gas injector according to the present invention. In this case, the gas injector preferably directly injects hydrogen, a noble gas, or another combustible gas, particularly into the combustion chamber of the internal combustion engine.

[0025] Advantageous embodiments of the present invention will be described in detail below with reference to the attached drawings. [Brief explanation of the drawing]

[0026] [Figure 1] This is a schematic cross-sectional view of a gas injector according to an advantageous first embodiment of the present invention. [Figure 2]It is a schematic enlarged partial cross-sectional view showing the damping device and the free stroke assembly of the gas injector shown in FIG. 1 in a closed state of the gas injector. [Figure 3] It is a schematic enlarged partial cross-sectional view showing the damping device and the free stroke assembly of the gas injector shown in FIG. 1 in a partially open state after the free stroke has advanced. [Figure 4] It is a schematic enlarged partial cross-sectional view showing the damping device and the free stroke assembly of the gas injector shown in FIG. 1 in a fully open state after the free stroke has advanced. [Figure 5] It is a schematic enlarged partial cross-sectional view showing the damping device and the free stroke assembly of the gas injector shown in FIG. 1 in a partially closed state after the free stroke has advanced. [Figure 6] It is a schematic partial cross-sectional view showing the damping device and the free stroke assembly of the gas injector according to the second embodiment of the present invention in a closed state. [Figure 7] It is a schematic partial cross-sectional view showing the damping device and the free stroke assembly of the gas injector according to the third embodiment of the present invention in a closed state. [Figure 8] It is a schematic partial cross-sectional view showing the damping device and the free stroke assembly of the gas injector according to the fourth embodiment of the present invention in a closed state. [Figure 9] It is a schematic cross-sectional view of the spring disk shown in FIG. 8. [Figure 10] It is a schematic plan view of the spring disk shown in FIG. 9. [Figure 11] It is a schematic partial cross-sectional view showing the damping device and the free stroke assembly of the gas injector according to the fifth embodiment of the present invention in a closed state.

[0027] Hereinafter, with reference to FIGS. 1 to 5, the gas injector 1 according to the first advantageous embodiment of the present invention will be described in detail.

[0028] As can be seen from Figure 1, the gas injector for injecting a gaseous medium into the combustion chamber 30 of an internal combustion engine includes a closing element 2 and an actuator 5 for operating the closing element 2. The closing element 2 is a valve needle. The actuator 5 is a magnetic actuator comprising an inner magnetic pole 50 and an armature 51 coupled to the closing element 2. A stopper 52 is formed on the inner magnetic pole 50 to limit the opening stroke of the closing element.

[0029] In this case, the closing element 2 opens and closes the through-opening 4 provided in the seal sheet 3. When the through-opening 4 is open, it becomes an annular passage, and in this case, the gas injector 1 is an injector that opens outward. That is, when the closing element 2 is open, it moves outward in the direction of arrow A toward the combustion chamber 30.

[0030] A gas inlet 31 is provided at the end opposite to the seal sheet 3. As can be seen from Figure 1, in this case, the gas inlet 31 is aligned with the closing element 2 and is positioned along the central axis that defines the axial direction XX of the gas injector.

[0031] In Figure 1, arrow B indicates the gas flow through the gas injector 1, starting from the gas inlet 31 and reaching the seal sheet 3.

[0032] Furthermore, as can be seen from Figure 1, the actuator 5 is sealed to the gaseous medium by a metal diaphragm 9. In this case, the metal diaphragm 9 is connected to the closing element 2 by welding. The metal diaphragm 9 has an opening in the middle, through which the closing element 2 is guided.

[0033] Furthermore, the gas injector 1 includes a return element 6. In this embodiment, the return element 6 is a cylindrical coil spring. The return element 6 returns the closing element 2 from the open state back to the initial closed state. In this case, the return element 6 is supported by a spring receiver 60 and a housing component 10a.

[0034] The gas injector 1 further includes a hydraulic damping device 7. This damping device 7 will be explained in particular in detail with reference to Figures 2 to 5.

[0035] The hydraulic damping device 7 is tuned to dampen the motion of the closing element 2. In this case, both the motion during the opening process and the motion during the closing process are damped. The hydraulic damping device in this case is tuned to perform damping using the liquid in the closed hydraulic chamber 8 provided in the damping device 7.

[0036] In this case, the hydraulic damping device 7 includes a first control chamber 80 and a second control chamber 88. Both control chambers 80 and 88 are located within the base body 17 of the hydraulic damping device 7. The first control chamber 80 works to dampen the return motion of the closing element, and the second control chamber 88 works to dampen the opening motion of the closing element.

[0037] As can be seen in Figure 2, a control cylinder 13 is positioned on the centering pin 18. The control cylinder 13 has multiple holes 13a, which connect the first control chamber 80 and the second control chamber 88. In this case, one aperture 14 is positioned in each of these holes, and the strength of the damping during the opening and closing processes can be adjusted by setting the diameter of the holes for the aperture 14.

[0038] Furthermore, the damping device 7 includes a first flexible element 11 and a second flexible element 12. In this embodiment, the first flexible element 11 and the second flexible element 12 are metal diaphragms. As can be seen from Figure 2, the closed hydraulic chamber 8 is formed by a hollow chamber provided in the base body 17, the first flexible element 11, and the second flexible element 12. In this case, the first flexible element 11 has a central opening through which a centering pin 18 is guided. In this case, the first flexible element 11 is connected to the centering pin 18 by welding.

[0039] The closed hydraulic chamber 8 is filled with a liquid, such as oil. As can be seen in Figure 2, in this case the centering pin 18 is formed with a through hole 18a, which is closed by a ball 86. In this case, easy filling of the closed hydraulic chamber 8 is possible.

[0040] The second flexible element 12 is fluid-tightly positioned on the base body 17 at the end face of the base body 17 facing the gas inlet 31. Since the first flexible element 11 and the second flexible element 12 are preferably metal diaphragms, a fluid seal with the base body 17 can be easily formed by welding.

[0041] A first subchamber 81 of the hydraulic chamber is formed between the base body 17 and the first flexible element 11. A second subchamber 82 is formed between the base body 17 and the second flexible element 12. The first subchamber and the second subchamber are fluidly connected to each other via a connecting region 83, which is a connecting hole.

[0042] Furthermore, the gas injector 1 includes a free stroke assembly 20. The free stroke assembly 20 is positioned between the hydraulic damper 7 and the actuator 5 in the axial direction XX (see Figure 1).

[0043] The free stroke assembly 20 includes a free stroke housing 21, a control element 22 which is a control disc in this embodiment, and a stopper element 23. As can be seen from Figure 2, the stopper element 23 is firmly bonded to the free stroke housing 21 by a weld. The control element 22 is located on the side of the closing element 2 opposite to the combustion chamber 30. In this case, a firm bond is formed between the control element 22 and the end of the closing element 2. This may be, for example, a weld, a press bond, or any other fixed mechanical bond.

[0044] The free-stroke housing 21 is coupled to the centering pin 18, in which case the free-stroke housing 21 and the centering pin 18 are formed, for example, as a single common component. However, the structure of the free-stroke housing 21 and the centering pin may be formed from multiple parts.

[0045] The gas injector 1 further includes a pot-shaped operating module housing 100, within which a free stroke assembly 20 and a partially damped device 7 are arranged. In this case, the operating module housing is coupled to the outer circumference of the base body 17 of the damped device 7 by welding.

[0046] The function of the gas injector 1 according to the present invention, which has a damping function optimized with respect to stroke, is as follows: Starting from the closed position of the gas injector 1 shown in Figures 1 and 2, the actuator 5 is activated. As a result, the armature 51 is attracted in the direction of the inner magnetic pole 50, so that the closing element 2 is lifted from the seal sheet 3 and the through opening 4 is opened. At this time, the return element 6 is preloaded.

[0047] Figure 2 shows the opening process for the closing element 2 indicated by arrow C. When the gas injector is closed, there is an axial free stroke S1 between the stopper element 23 and the control element 22. Since the control element 22 is coupled to the closing element 2, this free stroke S1 advances during the opening process, and as a result, the control element 22 comes into contact with the stopper element 23. This state is shown in Figure 3.

[0048] No damping occurs during the opening process of the gas injector until the state shown in Figure 3 is reached. However, the gas injector is not yet fully open. Subsequently, the remaining opening stroke of the gas injector is damped by the hydraulic damping device 7.

[0049] As indicated by arrow C in Figure 3, the closing element 2 continues to move in the opening direction, so the contact between the control element 22 and the stopper element 23 causes the free stroke housing 21 to move in the direction of arrow C, and consequently the centering pin 18 to move in the direction of arrow C. This is indicated by arrow D drawn on the centering pin 18 in Figure 4. Since the control cylinder 13 is tightly coupled to the centering pin 18, the control cylinder 13 also moves in the opening direction, as indicated by arrow E. However, this changes the volumes of the first control chamber 80 and the second control chamber 88. More precisely, the volume of the first control chamber 80 increases, and the volume of the second control chamber 88 decreases. Since the two control chambers 80 and 88 are fluidly connected to each other via the hole 13 and the throttling 14, this dampens the motion of the closing element until the armature 51 finally contacts the inner magnetic pole 50.

[0050] Figure 4 shows the damping stroke S2 ​​advanced by the control cylinder 13 in this case. Therefore, the maximum opening stroke of the closing element 2 is the sum of the free stroke S1 and the damping stroke S2. The damping strength can be easily adjusted in this case by setting the diameter of the hole for the aperture 14.

[0051] Furthermore, as can be seen from Figure 4, the volumes of the first subchamber 81 and the second subchamber 82 also change. This is because the first flexible element 11 is directly coupled to the centering pin 18 which moves in the axial direction XX. More precisely, the volume of the first subchamber 81 increases, and the volume of the second subchamber 82 decreases accordingly (see Figure 4).

[0052] For the gas injector closing process, the power supply to the actuator 5 is terminated, and a return force is applied to the closing element 2 by the preloaded return element 6. Figure 5 shows the first motion stroke for the return process in this case, in which the control element 22 coupled to the closing element 2 first moves along the free stroke S1, and then the control element 22 contacts the stepped portion 21a provided in the free stroke housing 21. This state is shown in Figure 5. Up to this point during the return process, the hydraulic damping device 7 remains without damping action.

[0053] As soon as the control element 22 contacts the stepped portion 21a of the free stroke housing 21, the free stroke housing 21 is also returned by the subsequent return movement of the return element 6, and consequently the centering pin 18 coupled to the free stroke housing 21 is also returned. As a result, the control cylinder 13 is also returned to the initial position shown in Figure 2. The return movements of these components are indicated by arrows F in Figure 5.

[0054] Therefore, as soon as the control element 22 contacts the free-stroke housing 21, damping is performed by the hydraulic damping device 7 due to the movement of the centering pin 18. This is because the volume in the first control chamber 80 and the volume in the second control chamber 88 return to the initial position shown in Figure 2. In Figure 5, the maximum damping stroke S2 ​​that must be advanced until the closing element 2 is completely sealed by the seal sheet 3 is shown by a dashed line. Therefore, only the final movement during the return of the gas injector is damped.

[0055] Therefore, according to the present invention, by appropriately setting the free stroke S1 with the free stroke assembly 20, damping during the opening process can be limited to only the final opening stroke of the closing element. Similarly, during the closing process, the damping action of the hydraulic damping device 7 is limited to the final axially advanced stroke (damping stroke S2) of the closing element 2. This makes it possible to form the hydraulic damping device 7 in an extremely small size and particularly inexpensive manner using a single flexible element 11, 12 provided at each end of the base body. Furthermore, the inner and outer diameters of the first control chamber 80 and the second control chamber 88 are equal. This allows the base body 17 to be formed in a particularly simple manner. In this case, the mobility of the centering pin 18 can be ensured by a correspondingly formed radial gap between the centering pin 18 and the base body 17 or between the control element 22 and the base body 17. In this case, another means is also provided to influence the damping action by setting the gap height of the radial gap provided in the centering pin 18 or the control element 22.

[0056] Therefore, according to the present invention, damping can be limited to the final stroke section during the opening and closing of the gas injector. In this case, the free stroke S1 is greater than the damped stroke S2. This allows for a rapid switching time, and subsequently, large-scale gas injection can be rapidly performed by the initial, undamped movement of the closing element during opening. The same applies to the closing process, which is made possible on a large scale by the initial, undamped closing stroke.

[0057] Figure 6 schematically shows a partial cross-sectional view of a gas injector according to a second embodiment of the present invention. Parts that are identical in terms of their function or function are indicated by the same reference numerals as in the first embodiment.

[0058] Unlike the first embodiment, in the second embodiment, the free stroke housing 21 is directly coupled to the closing element 2. Furthermore, the free stroke assembly 20 includes a control pin 24, which has a head 24a located within the free stroke housing 21 and a shaft portion 24b coupled to the centering pin 18. The coupling between the control pin 24 and the centering pin 18 can be achieved, for example, by welding. Thus, in the second embodiment, during the opening process, the free stroke housing 21 is moved together with the closing element 2 until the free stroke S1 is advanced. Then, as the opening motion of the closing element 2 continues, the control pin 24 is also moved axially, as the head of the control pin 24 contacts the stopper element 23. Since the control pin 24 is tightly coupled to the centering pin 18, it is then damped by a hydraulic damping device 7 for the remainder of the opening stroke, as described in the first embodiment. During the closing process, the control pin 24 first moves along the free stroke S1, as in the first embodiment, and then the head of the control pin 24 contacts the stopper surface 21b provided on the free stroke housing 21, after which the centering pin 18 can be returned via the control pin 24. In this case, the final closing stroke of the closing element 2 is also damped by the damping device 7. For other points, this embodiment corresponds to the first embodiment, so you can refer to the description given in the first embodiment.

[0059] Figure 7 shows a partial cross-sectional view of a gas injector according to a third embodiment of the present invention. Parts that are identical in terms of function or function are indicated by the same reference numerals as in the previous embodiments.

[0060] The third embodiment is substantially equivalent to the second embodiment, in which the free stroke assembly 20 also includes the control pin 24. However, in the third embodiment, the centering pin 18 is formed from two parts, in which case a sleeve 28 is provided to connect the centering pin 18 to the control pin 24. Furthermore, in the third embodiment, the control cylinder that was present in the first two embodiments is formed integrally with the centering pin 18. This is indicated by reference numeral 18b in Figure 7. In other respects, this embodiment corresponds to the prior embodiments, so the description given in the prior embodiments can be referenced.

[0061] Figures 8 to 10 show a gas injector according to a fourth embodiment of the present invention. Parts that are identical in any respect to the same part or function are indicated by the same reference numerals as in the preceding embodiments.

[0062] The fourth embodiment makes it possible to reduce leakage from the first control chamber 80 and the second control chamber 88 into the hydraulic chamber 8 compared to the prior embodiments. Thus, reliable function of the hydraulic damping device 7 can be ensured, especially over extremely long operating times. To this end, the fourth embodiment has a modified guide for the centering pin 18, unlike the prior embodiments. As can be seen from Figure 8, the centering pin 18 is guided by the seal disc 19. Since the inner circumferential region of the seal disc 19 has a radius R1, a contact line for guidance is obtained between the seal disc 19 and the centering pin 18. This allows the gap in the region between the seal disc 19 and the centering pin 18 to be kept extremely small.

[0063] Furthermore, a spring disc 110 is provided that applies a spring force F to the seal disc 19 in the axial direction XX. This provides an axial seal between the seal disc 19 and the base body 17 of the hydraulic damping device 7.

[0064] As can be seen in detail from Figures 9 and 10, which show the spring disc 110 in a cross-sectional view (Figure 9) and a plan view (Figure 10), the spring disc 101 has a substantially pot-like shape, in which the bottom has a central opening through which the centering pin 18 is guided. The spring disc 101 includes a retaining region 102, which is located on the outer circumferential surface of the spring disc 101 and is fixed in position to the base body 17 by frictional connection. Furthermore, three protrusions 103 are provided, which are arranged at equal intervals of 120° (see Figure 10) and are in contact with the seal disc 19. A spring force F is applied to the seal disc 19 through these protrusions 103. Notches 104 are provided between these protrusions, which allows for sufficient movement of the centering pin 18 when it moves in the axial direction XX.

[0065] In this case, the control cylinder 13 is located at least partially inside the pot-shaped spring disc 101. As can be seen particularly in Figure 8, the control cylinder 13 has a flange 113 that is directed radially outward, and in this case, a throttling gap 14 is formed between the flange 113 and the base body 17. Through this throttling gap 14, fluid can flow from the first control chamber 80 into the second control chamber 88 and from the second control chamber 88 into the first control chamber 80.

[0066] Furthermore, a seal ring 15 is provided, and a second R portion R2 and a conical portion 15a are formed on the inner circumferential surface of this seal ring 15. As a result, the first control chamber 80 is sealed relatively well from the hydraulic chamber 8.

[0067] Furthermore, as can be seen from Figure 8, in the base body 17, a conical portion 17a is formed between the base body and the centering pin 18, so that the fluid reaches from the hydraulic chamber 8 to the seal disc 19. This ensures good mobility of the centering pin 18 in particular.

[0068] The first flexible element 11, coupled to the centering pin 18, has relatively high rigidity in the radial direction. Therefore, the first flexible element 11 cannot compensate for radial errors, or can only compensate to a limited extent. Thus, in the fourth embodiment, the centering pin 18 is guided radially to the seal disk 19. In this case, an extremely small radial gap can be achieved.

[0069] By providing a conical portion 17a on the base body 17 and a conical portion 15a on the seal ring 15, the tilt position of the centering pin 18 that may occur during operation can be compensated very well. In this case, the cone apex angle is preferably in the range of 0.5° to 30°, and particularly in the range of 1° to 10°. For other points, this embodiment corresponds to a prior embodiment, so you can refer to the description in the prior embodiment.

[0070] Next, with reference to Figure 11, a gas injector according to a fifth embodiment of the present invention will be described in detail. Parts that are identical in any respect to their function are indicated by the same reference numerals as in the previous embodiments.

[0071] The fifth embodiment is substantially equivalent to the fourth embodiment, in which, instead of the spring disc used in the fourth embodiment, the fifth embodiment uses a press-fitted disc 119, which presses the seal disc 19 against the base body 17 of the hydraulic damping device 7. In this case, a press joint is formed between the press-fitted disc 119 and the base body 17. Similar to the fourth embodiment, the seal disc 19 guides the centering pin 18 in the inner circumferential region having R portion R1. On the radially outer circumferential surface, a fluid-filled chamber 120 remains in the seal disc 19, so the centering pin can also perform a compensatory motion directed radially, if possible. In other respects, this embodiment is equivalent to the preceding embodiment, so refer to the description in the preceding embodiment.

Claims

1. A gas injector for blowing in a gaseous medium, A closing element (2) that opens and closes a through-opening (4) provided in the seal sheet (3), The closing element (2) is returned to its initial closed position by a return element (6), An actuator (5) that operates the closing element (2), A hydraulic damping device (7) for damping the motion of the closed element (2), wherein the hydraulic damping device (7) is adjusted to provide damping using liquid in a closed hydraulic chamber (8), A free stroke assembly (20) is positioned between the closing element (2) and the hydraulic damping device (7), and is adjusted to dampen the motion of the closing element (2) only after it has advanced a predetermined free stroke (S1), A gas injector for blowing in a gaseous medium, including [a specific substance].

2. The gas injector according to claim 1, wherein the complete opening stroke of the closing element (2) includes the free stroke (S1) and the damping stroke (S2) of the hydraulic damping device (7).

3. The gas injector according to claim 2, wherein the damping stroke (S2) is smaller than the free stroke (S1).

4. The gas injector according to claim 3, wherein the ratio of the damped stroke (S2) to the free stroke (S1) is in the range of 0.06 to 0.12, and particularly in the range of 0.08 to 0.

10.

5. The free stroke assembly (20) includes a free stroke housing (21), a control element (22) disposed within the free stroke housing (21), and a stopper element (23) fixed in position within the free stroke housing (21), wherein the free stroke (S1) is formed between the control element (22) and the stopper element (23), or The free stroke (S1) is formed between the control element (22) and the free stroke housing (21). A gas injector according to claim 1 or 2.

6. The gas injector according to claim 5, wherein the free stroke housing (21) is coupled to the hydraulic damping device (7) and the control element (22) is coupled to the closing element (2), or the free stroke housing (21) is coupled to the closing element (2) and the control element (22) is coupled to the hydraulic damping device (7).

7. The gas injector according to claim 1 or 2, wherein the hydraulic damping device (7) includes a base body (17) and a centering pin (18) axially movable within the base body (17), the centering pin (18) being actuatedly coupled to the free stroke assembly (20).

8. The gas injector according to claim 1 or 2, wherein the hydraulic damping device (7) has a first control chamber (80) and a second control chamber (88), and the two control chambers are connected to each other via a fluid connection.

9. The gas injector according to claim 8, wherein the fluid connection portion includes a throttle (14), the throttle (14) is located in a control cylinder (13) that separates the first control chamber (80) and the second control chamber (88), and the closing element (2) is attenuated by the volume change in the first control chamber and the second control chamber via the throttle (14) during the opening and closing processes.

10. The gas injector according to claim 7, wherein the damping device (7) comprises a base body (17), a first flexible element (11), and a second flexible element (12), the centering pin (18) is coupled to the first flexible element (11), and the first flexible element (11) and the second flexible element (12) form a housing region of the closed hydraulic chamber (8).

11. The gas injector according to claim 10, wherein the first flexible element and / or the second flexible element is a metal diaphragm and / or the first flexible element and the second flexible element are bellows.

12. The first flexible element (11) is positioned on the base body (17), and a first partial chamber (81) of the hydraulic chamber (8) is formed between the base body (17) and the first flexible element (11). The second flexible element (12) is positioned on the base body (17), and a second sub-chamber (82) of the hydraulic chamber (8) is formed between the base body (17) and the second flexible element (12). The gas injector according to claim 10, wherein the first subchamber (81) and the second subchamber (82) are fluidly connected to each other via a connecting region (83).

13. The gas injector according to claim 1 or 2, wherein the free stroke assembly (20) and the damping device (7) are arranged in the axial direction (X-X) of the gas injector on the side of the actuator (5) opposite to the seal sheet (3).

14. The gas injector according to claim 13, wherein the free stroke assembly (20) and the hydraulic damping device (7) are formed as a pre-assembled module (100).

15. The gas injector according to claim 10, wherein the centering pin (18) is guided by the first flexible element (11) and a seal disc (19), the seal disc (19) being pre-biased by a spring disc (101).

16. The gas injector according to claim 15, wherein the spring disc (101) is formed in a pot shape and includes a retaining edge (102), a projection (103) protruding in the axial direction (X-X), and an axial notch (104).

17. The gas injector according to claim 10, wherein the centering pin (18) is guided by the first flexible element (11) and a seal disc (19), the seal disc (19) being pre-biased axially by a press-fitted disc (119) which is bonded to the base body (17) of the hydraulic damping device by press bonding.

18. The gas injector according to claim 17, wherein a compensation chamber (120) filled with liquid is provided on the radially outer circumferential surface of the seal disc (19).

Images