Gas injector with armature damper

Abstract

The invention relates to a gas injector for blowing in a gaseous medium, comprising a closing element (2) which releases and closes a through-hole (4) on a sealing seat (3); a restoring element (6) which resets the closing element (2) into a closed initial position; an electromagnetic actuator (5) having an armature (51) with a maximum armature travel (S0), the electromagnetic actuator (5) actuating the closing element (2); and an armature damper (7), which is designed to reduce the speed of the armature (51) before the armature (51) impinges on the armature stop (53) during the opening of the gas injector.

Description

Technical Field

[0001] The invention relates to a gas injector for injecting a gaseous medium, such as hydrogen, natural gas or the like, directly into a combustion chamber of an internal combustion engine, the gas injector having an armature damper. Background Art

[0002] A number of different designs of gas injectors are known from the prior art. Compared to injectors for liquid media, such as fuel injectors, gas injectors must perform a very large stroke, since they inject gaseous media. However, this can lead to high wear on components in the gas injector, in particular on sealing seats and stroke limits. The high switching forces required in the gas injector also increase the wear on components during operation. Summary of the invention

[0003] In contrast, the gas injector for blowing gaseous media, especially hydrogen or natural gas, according to the present invention, which has the features of claim 1, has the advantage that the wear of components, especially the wear on the armature, can be significantly reduced. In addition, the gas injector according to the present invention has a significantly improved noise performance. This is achieved according to the present invention in the following way: the gas injector has a closing element, which releases and closes the through hole on the sealing seat. The gas injector also includes a reset element, which resets the closing element to a closed initial position. In addition, the gas injector includes an electromagnetic actuator with an armature, wherein the electromagnetic actuator operates the closing element, and wherein the armature has a maximum armature stroke S0; in addition, an armature damper is provided, which is arranged to reduce the speed of the armature before the armature hits the armature stop, especially the inner pole of the electromagnetic actuator, during the opening process of the gas injector. Therefore, it is possible to achieve a significant reduction in the wear on the armature and the armature stop, and excessive wear on the contact point between the armature and the armature stop during the opening stroke of the gas injector can be prevented.

[0004] Dependent claims 4 disclose advantageous developments of the invention.

[0005] The armature damper is preferably arranged on the side of the armature facing away from the sealing seat. This does not restrict the function and performance of the electromagnetic actuator, and the armature can perform the maximum designed armature stroke S0 until the armature stop without interference by the armature damper in this area.

[0006] The armature damper preferably comprises a spring element, which is arranged on the side of the armature facing away from the sealing seat. In other words, the spring element is arranged on the back side of the armature. This results in many degrees of freedom in the configuration of the spring element and also enables a compact structure of the gas injector.

[0007] Further preferably, the closing element comprises a valve needle and an armature pin, wherein the armature is fixed to the armature pin. The two-part structure of the closing element also increases the degree of freedom with regard to the design of the gas injector component.

[0008] According to another preferred embodiment of the invention, the armature damper comprises a preferably pot-shaped support element, which is fixed to the inner housing of the gas injector. The support element is used to support the spring element. In the pot-shaped configuration of the support element, radial positioning of the spring element is also ensured when a cylindrical helical spring is used as the spring element.

[0009] Further preferably, the armature damper further comprises a pressure plate and a first adjustment plate. The spring element of the armature damper is arranged between the pressure plate and the support element of the armature damper. In addition, the position of the pressure plate in the axial direction is defined by means of the first adjustment plate. This creates an easy-to-operate adjustment possibility for the desired preload of the spring element of the armature damper.

[0010] According to another preferred configuration of the present invention, the armature damper further comprises a second adjusting disk, which is fixed on the closing element, wherein an axial gap S1 is defined between the pressure disk and the second adjusting disk in the closed state of the gas injector, wherein the axial gap S1 is smaller than the maximum armature stroke S0. The second adjusting disk is preferably fixed on the armature column.

[0011] It is further preferred that the support element has a guide region on its inner circumference for the closing element, in particular the armature pin.

[0012] Further preferably, the spring element of the armature damper is a cylindrical helical spring or a spring washer. The spring washer can be, for example, a wave spring or a disc spring.

[0013] Further preferably, the gas injector further comprises a hydraulic damper, which is arranged on the side of the closing element facing away from the sealing seat. The hydraulic damper is preferably provided to assist the closing element during the opening process as well as during the closing process. In this case, in combination with the armature damper, a particularly good damping of the armature is achieved during the opening process, so that wear phenomena on the armature and the armature pin can be avoided. The hydraulic damper can also compensate for temperature-induced length changes of components of the gas injector.

[0014] Further preferably, the armature damper is provided to be activated with a time delay after the start of the opening process of the gas injector, wherein the axial play between the pressure disk and the second adjusting disk defines the time delay.

[0015] The gas injector is preferably an outwardly opening gas injector. Further preferably, the gas injector is configured to inject the gaseous fuel directly into the combustion chamber of the internal combustion engine.

[0016] In addition, the present invention also relates to an internal combustion engine with a gas injector according to the present invention. Here, the gas injector preferably blows hydrogen, natural gas or other combustible gases directly into the combustion chamber of the internal combustion engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the accompanying drawings:

[0018] Figure 1 : A schematic cross-sectional view of a gas injector according to a first preferred embodiment of the present invention;

[0019] Figure 2 : In the closed state Figure 1 A schematic partial enlarged cross-sectional view of a gas injector;

[0020] Figure 3 : In partially open state Figure 1 A schematic partial enlarged cross-sectional view of a gas injector;

[0021] Figure 4 : A schematic cross-sectional view of a gas injector according to a second preferred embodiment of the present invention;

[0022] Figure 5 : Figure 4 Schematic representation of the individual components of the armature damper of the second exemplary embodiment of the gas injector. DETAILED DESCRIPTION

[0023] Refer to the following Figures 1 to 3 A gas injector 1 according to a first preferred embodiment of the present invention is described in detail.

[0024] As from Figure 1 It can be seen that a gas injector 1 for injecting a gaseous medium into a combustion chamber 30 of an internal combustion engine comprises a closing element 2 and an electromagnetic actuator 5 which actuates the closing element 2. The closing element 2 is designed in two parts and comprises a valve needle 20 and an armature pin 21.

[0025] The electromagnetic actuator 5 comprises an inner pole 50, an armature 51 and a coil 52. An armature stop 53 is formed on the inner pole 50, which limits the opening travel of the closing element 2.

[0026] The closing element 2 has a valve disk 20a on the valve needle 20 on the side pointing toward the combustion chamber 30, which seals on the sealing seat 3. During the opening process, the closing element 2 releases the annular through hole 4 on the sealing seat 3 and closes it. The gas injector is thus an injector that opens outwards, wherein the closing element 2 opens in the direction of the arrow A (see Figure 1 ) moves outward into the combustion chamber 30.

[0027] exist Figure 1 The arrow C indicates that the gaseous fuel is blown into the combustion chamber 30, wherein it should be noted that Figure 1 The closed state of the gas injector is shown.

[0028] A gas inlet 31 is provided at the opposite end of the sealing seat 3. Figure 1 It can be seen that the gas inlet 31 is arranged here colinearly with the closing element 2 on a central axis which defines the axial direction XX of the gas injector 1 .

[0029] exist Figure 1 In FIG. 1 , arrow B indicates that gas flows from the gas inlet 31 through the gas injector 1 to the sealing seat 3 .

[0030] The reset element 6 resets the gas injector 1 to the position after the opening process. Figure 1 In the closed state shown. In this embodiment, the restoring element is a cylindrical helical spring which is supported on a spring washer 60 and the housing component 10a.

[0031] The gas injector 1 further comprises an armature damper 7 which is provided for braking and damping the speed of the armature 51 before it strikes the armature stop 53 during the opening process of the gas injector 1 .

[0032] The armature damper 7 includes a pot-shaped supporting element 70, a spring element 75 and an inner housing 71. The inner housing 71 is fixed to the inner pole 50 in a sleeve-like manner.

[0033] The armature damper 7 further comprises a pressure plate 72, a first adjustment plate 73 and a second adjustment plate 74. Figure 2 It can be seen that the spring element 75 is arranged between the pressure disk 72 and the pot-shaped support element 70. The spring element 75, which is a cylindrical helical spring in this embodiment, is stabilized in the radial direction by the pot-shaped configuration of the support element 70. Figure 1 and Figure 2 In the closed state shown, the spring element 75 has a spring force F, by means of which the pressure disk 72 is pressed against the first adjusting disk 73 .

[0034] The first adjustment disk 73 is fixed on the inner circumference of the inner shell 71 .

[0035] A guide 70 a for the armature pin 21 is provided on the inner circumference of the support element 70 .

[0036] The second adjustment disk 74 is fixed to the closing element 2, more precisely to the armature column 21. Figure 2), there is an axial gap S1 between the second adjustment disk 74 and the pressure disk 72. Therefore, the preload force of the spring element 75 can be adjusted by positioning the first adjustment disk 73 in the axial direction XX (this positioning defines the axial position of the pressure disk 72).

[0037] The pressure disk 72 is arranged inside the inner housing 71 so as to be axially movable.

[0038] like Figure 1 and Figure 2 As shown, the armature pin 21 is guided freely movably by an inner pole 50, wherein preferably a guide 50a is provided for the armature pin 21. The armature 51 is fixedly connected to the armature pin 21 by means of a welded connection 51a.

[0039] In the closed state of the gas injector 1 , the maximum opening stroke of the closing element 2 is defined by the armature stroke S0 . The armature stroke S0 is formed between the armature 51 and the inner pole 50 . The armature stroke S0 is greater than the axial gap S1 between the second adjusting disk 74 and the pressure disk 72 .

[0040] By providing the axial gap S1, the armature damper 7 is activated with a time delay during the opening process of the gas injector. For the opening process of the gas injector, the coil 52 is energized, whereby the armature 51 is moved in the direction of the arrow D (see Figure 2 ) is attracted in the direction of the inner pole 50. By the movement of the armature 51, the armature pin 21 and thus the valve needle 20 are moved in the axial direction XX, so that the gas injector 1 is opened at the sealing seat 3 and the through-hole 4 is released.

[0041] As a result, gaseous fuel can be blown into the combustion chamber 30 (arrow C). Since the second adjustment disk 74 is fixedly connected to the armature column 21, the second adjustment disk 74 is also moved in the axial direction XX during the opening process. Here, the second adjustment disk 74 abuts against the pressure disk 72 after passing through the axial gap S1. This state is Figure 3 As shown in . Until the axial gap S1 is overcome, the armature damper 7 has not yet taken effect, thereby enabling delayed actuation of the armature damper 7 .

[0042] When the armature 51 is Figure 2 When the position shown continues to be attracted in the direction of arrow D toward the inner pole 50, the second adjustment disk 74 also continues to move in the direction of the sealing seat 3 and thereby entrains the pressure disk 72 arranged freely movably in the inner housing 71. As a result, the spring element 75 is compressed, thereby braking the armature 51 in terms of its movement speed. Figure 3In the state shown, the armature 51 still has to overcome the remaining partial axial gap S2 between the armature 51 and the inner pole 50 until the gas injector is fully opened. When the armature 51 abuts against the armature stop 53 on the inner pole 50, the gas injector is fully opened.

[0043] When the residual axial gap S2 is passed, the armature damper 7 is activated, so that the stop speed of the armature 51 hitting the inner pole 50 is significantly reduced, thereby reducing the wear on these components. In addition, the noise generated by the armature 51 hitting the inner pole 50 can also be reduced, thereby significantly improving the noise performance of the gas injector 1.

[0044] Once the blowing is finished, the coil 52 is de-energized so that the reset element 6 resets the closing element 2 to the position where the closing element 2 is closed. Figure 1 and Figure 2 In the initial position shown. Here, the armature 51 is reset from the armature stop 53 to the initial position. The pressure plate 72 is also reset to the initial position by means of the spring element 75. Figure 2 The first adjusting disk 73 is shown in the closed position.

[0045] The gas injector 1 further comprises a hydraulic damper 8, which is operatively connected to the closing element 2. The hydraulic damper 8 is provided for braking and damping the closing element 2, in particular when returning it from the open state to the closed state. This keeps the wear on the sealing seat 3 of the gas injector low. By providing the armature damper 7, the hydraulic damper 8 can be designed very simply and in particular only for damping the closing element 2 during the return process.

[0046] The armature damper 7 can therefore be designed optimally for the armature and for damping during the opening process, and the hydraulic damper 8 can be designed optimally for damping when the gas injector is closed.

[0047] Figure 4 and Figure 5 A gas injector 1 according to a second exemplary embodiment of the invention is shown, wherein identical or functionally identical components are denoted by the same reference numerals.

[0048] Especially from Figure 5 It can be seen that the armature damper 7 of the second exemplary embodiment comprises a wave spring as spring element 75. As in the first exemplary embodiment, the wave spring is arranged here between the support element 70 and the pressure disk 72. The support element 70 can again be designed as a simple disk.

[0049] Otherwise, this exemplary embodiment corresponds to the preceding exemplary embodiments, so that reference is made to the relevant description there.

Claims

1. A gas injector for blowing a gaseous medium, comprising: - a closing element (2) which releases and closes the through hole (4) on the sealing seat (3); - a reset element (6) which resets the closing element (2) into a closed initial position; an electromagnetic actuator (5) having an armature (51), the armature having a maximum armature stroke (S0), wherein the electromagnetic actuator (5) actuates the closing element (2); An armature damper (7) is provided for reducing the speed of the armature (51) before the armature (51) strikes an armature stop (53) during the opening process of the gas injector.

2. The gas injector according to claim 1, wherein: The armature damper (7) is arranged on a side of the armature (51) facing away from the sealing seat (3).

3. The gas injector according to claim 2, wherein: The armature damper (7) has a spring element (75) which is arranged on a side of the armature (51) facing away from the sealing seat (3).

4. A gas injector according to any one of the preceding claims, wherein: The closing element (2) comprises a valve needle (20) and an armature pin (21), wherein the armature (51) is fixed to the armature pin (21).

5. The gas injector according to any one of claims 3 or 4, wherein: The armature damper (7) comprises a support element (70) for the spring element (75) and an inner housing (71), wherein the support element (70) is fastened to the inner housing (71).

6. The gas injector according to claim 5, wherein: The armature damper (7) further comprises a pressure plate (72) and a first adjustment plate (73), wherein the spring element (75) is arranged between the pressure plate (72) and the support element (70), and wherein the position of the pressure plate (72) in the axial direction (XX) is defined by means of the first adjustment plate (73).

7. The gas injector according to claim 6, further comprising a second adjustment disk (74), the second adjustment disk being fixed on the closing element (2), wherein In a closed state of the gas injector, the second adjustment disk (74) defines an axial gap (S1) between the pressure disk (72) and the second adjustment disk (74), wherein the axial gap (S1) is smaller than a maximum armature stroke (S0).

8. A gas injector according to any one of the preceding claims, wherein: The support element (70) has a guide region (70a) for the closing element (2) on its inner circumference.

9. The gas injector according to any one of claims 3 to 8, wherein: The spring element (75) is a helical spring or a spring washer or a wave spring or a disc spring.

10. The gas injector according to any one of claims 7 to 9, wherein: The armature damper (7) is designed to be activated with a time delay after the start of an opening process of the gas injector, wherein an axial play (S1) between the pressure disk (72) and the second adjusting disk (74) defines the time delay.

11. The gas injector according to claim 1, further comprising a hydraulic damper (8), which is arranged on the end of the closing element (2) facing away from the sealing seat and is provided for damping at least during the opening process of the gas injector.

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