Gas injector

Abstract

The present invention relates to a gas injector for injecting a gaseous medium, comprising a magnetic actuator, comprising an armature, an inner pole and a coil, and a closing element that opens and closes a passage opening on a sealing seat, wherein the armature is formed in two parts with a first armature element and a second armature element, wherein the first armature element is directed towards the inner pole and has a first stop surface for contact with a second stop surface of the inner pole, wherein the closing element is firmly connected to the second armature part, wherein the first armature element and the second armature element are loosely joined together, and wherein a conical contact area is formed between the first armature element and the second armature element.

Description

[0001] R.414685

[0002] - 1 -

[0003] Description

[0004] title

[0005] Gas injector

[0006] State of the art

[0007] The present invention relates to a gas injector for injecting a gaseous medium, in particular a gaseous fuel or urea.

[0008] Gas injectors are known in various designs from the prior art. Magnetic actuators are also used, particularly for cost reasons. However, the physical limitations of the base materials used for the magnetic actuator components can lead to actuator failure and thus to the failure of the gas injector. Another problem area with gas injectors concerns their wear behavior. In particular, sudden stress peaks can occur at the contact surfaces between an inner pole and a magnetic armature of the actuator, as well as uncontrolled flexing and rolling behavior of the two components, which can lead to damage.

[0009] Disclosure of the invention

[0010] The gas injector according to the invention for injecting a gaseous medium with the features of claim 1 has the advantage that wear during operation can be significantly reduced. In particular, wear between an inner pole of a magnetic actuator and an armature can be reduced. Furthermore, the gas injector exhibits significantly simpler and safer operating behavior, whereby various individual parts of the gas injector can be optimized with regard to their function. This is achieved according to the invention by the fact that the gas injector has a magnetic actuator with R.414685

[0011] - 2 - The gas injector comprises an inner pole, an armature, and a coil. Furthermore, the gas injector includes a closing element that opens and closes at least one through-opening at a sealing seat. The gaseous medium to be injected is injected through the through-opening into a subsequent chamber. The armature is designed in two parts, consisting of a first and a second armature element. The first armature element faces the inner pole and has a first stop surface for contact with a second stop surface of the inner pole. The second armature element is fixedly connected to the closing element and thus moves together with it. The first and second armature elements are loosely joined, with a conical contact area formed between them. The two-part armature design allows, in particular, the critical areas of the armature to be optimized independently of one another.The first contact surface of the first armature element can be optimized with regard to contact with the inner pole. The conical contact area between the first and second armature elements mutually dampens dynamic effects between them during operation, particularly during the opening of the gas injector. This protects the components and extends the service life of the gas injector. Furthermore, the conical contact area between the first and second armature elements offers the advantage that, due to the conical contact surfaces on both, the first armature element is additionally centered during opening, preventing it from tilting or similar movement when it impacts the second contact surface on the inner pole.During the closing process, the closing element is protected because the self-centering action of the conical contact area between the first and second anchor elements ensures that the closing element engages the sealing surface securely and precisely, creating a tight seal. Furthermore, unwanted flexing movements and / or critical rolling behavior are prevented during both the opening and closing processes of the two anchor elements, thus significantly reducing the stress on the gas injector components.

[0012] The dependent claims describe preferred embodiments of the invention. R.414685

[0013] - 3 -

[0014] Preferably, the first anchor element has a mass that is smaller than the mass of the second anchor element. This has the advantage that, during the opening process, a smaller mass impacts the second stop surface of the inner pole. This reduces stress on the components.

[0015] The anchor preferably comprises a hinged bearing between the first and second anchor elements. The hinged bearing is preferably formed by an arcuate section on one of the two anchor elements and a cylindrical section on the other. The arcuate section is preferably a circular segment. Thus, the hinged bearing is realized by contact between an arc and a cylinder. The cylindrical section is particularly preferably formed on the first anchor element and the arcuate section on the second anchor element. Preferably, an annular gap is provided in the axial direction between the hinged bearing and the conical contact area, which further improves the mobility of the two anchor elements relative to each other.

[0016] According to a further preferred embodiment of the invention, the anchor is guided on the first and / or the second anchor element. It is possible that only one of the two anchor elements has a guide area, or preferably both anchor elements have a guide area. The guide areas are particularly preferably guided on an inner circumference of a cylindrical valve sleeve.

[0017] Furthermore, the gas injector preferably includes a return element, in particular a spring element, for returning the armature to a closed starting position. The return element is preferably arranged in the inner region of the inner pole. This allows for a space-optimized design of the gas injector. The return force of the return element can preferably be adjusted by means of an adjusting sleeve, the axial position of which can be set during assembly and against which the return element is supported.

[0018] Preferably, a first center of gravity of the first anchor element and a second center of gravity of the second anchor element lie on a central axis XX of the gas injector. The first and second centers of gravity are located apart. See R.414685

[0019] - 4 - Preferably, the combined center of gravity of the first and second anchor elements is also located on the central axis of the gas injector. The combined center of gravity is preferably located closer to the sealing seat than the center of gravity of the first and second anchor elements.

[0020] By positioning the centers of gravity of the first and second anchor elements on the central axis, it can be ensured that the centers of gravity of the moving masses can be arranged centrally in an overall component geometry.

[0021] Preferably, the first and second centers of gravity of the first and second anchor elements are arranged near their respective guide areas. That is, in the axial direction of the central axis XX, the first center of gravity lies at the level of a first guide area of ​​the first anchor element, and the second center of gravity lies at the level of a second guide area of ​​the second anchor element.

[0022] Preferably, the gaseous medium is guided at least partially through the armature towards the sealing seat. Preferably, the first armature element has a central through-opening, and the second armature element also preferably has a central through-opening. Additionally, preferably, branch bores to the outer surface of the second armature element are provided, so that the gaseous medium can flow towards the sealing seat both through the interior and around the outer circumference of the second armature element. This allows for injection advantages, since gaseous media typically have larger volumes compared to liquid media, and therefore a larger volume flow rate, for example in the case of fuels per unit of power, needs to be injected.

[0023] The sealing seat is preferably annular in shape between the closing element and a sealing seat component. Preferably, an elastomer component or the like is provided on at least one of the two sealing partners of the sealing seat. The elastomer component is particularly preferably arranged on the closing element and further preferably has a sleeve-like shape with a radially outwardly extending, circumferential flange. The through-openings are preferably arcuate or kidney-shaped. R.414685

[0024] - 5 -

[0025] Preferably, the gas injector is configured to inject a gaseous fuel into an intake manifold and / or directly into a combustion chamber and / or an anode module of a fuel cell.

[0026] Furthermore, the invention relates to an internal combustion engine with a gas injector according to the invention.

[0027] Brief description of the drawings

[0028] A preferred embodiment of the invention is described in detail below with reference to the accompanying drawing. The drawing shows:

[0029] Figure 1 shows a schematic partial sectional view of a gas injector according to a preferred embodiment of the invention.

[0030] Figure 2 is a schematic, enlarged partial sectional view of the

[0031] Gas injector of Figure 1 and

[0032] Figure 3 shows a schematic partial sectional view of a section of a

[0033] Anchor of the gas injector according to the invention.

[0034] Preferred embodiments of the invention

[0035] A gas injector 1 according to a preferred embodiment of the invention is described in detail below with reference to Figures 1 to 3.

[0036] The gas injector 1 is preferably configured to inject a gaseous medium, in particular a fuel or urea, into an internal combustion engine.

[0037] The gas injector 1 comprises a magnetic actuator 20 with an armature 2, an inner pole 3 and a coil 4.

[0038] The inner pole 3 is fixed in a valve sleeve 13. R.414685

[0039] - 6 -

[0040] The inner pole 3 and the armature 2 are preferably made of materials with magnetic properties. The inner pole 3 may also have a magnetic separator, for example a nickel coating. The armature may also have a coating.

[0041] The gas injector 1 further comprises a closing element 5. A sealing seat component 7 preferably has several through-openings 8, which can be arcuate or kidney-shaped. The closing element 5 releases and closes the through-openings 8 at a sealing seat 6.

[0042] As can be seen from Figures 1 and 2, the sealing seat 6 is annular in shape radially outside the through-openings 8 and radially inside the through-openings 8. The closing element 5 has an elastomeric sealing element 10, which has a cylindrical main body 10a and a radially outwardly projecting sealing flange 10b.

[0043] Thus, the sealing seat 6 comprises two annular sealing areas radially inside and radially outside the through-openings 8. The closing element 5 is essentially sleeve-shaped, which allows the elastomeric sealing element 10 to be easily and securely fixed to an inner circumference of the closing element 5. Gaseous medium can therefore be guided along the outer circumference and also through a central opening 50 of the closing element 5. This is indicated schematically by arrow A in Figure 1.

[0044] The anchor 2 of the gas injector is designed in two parts and comprises a first anchor element 21 and a second anchor element 22. The anchor 2 can be seen in detail in Figures 2 and 3.

[0045] The locking element 5 is, as can be seen from Figure 2, firmly connected to the second anchor element 22 and moves together with the second anchor element.

[0046] Through the anchor 2, a central bore 16 is formed through both anchor elements 21 and 22, which guides gaseous medium along a central axis XX of the gas injector to the central opening 50 in the closing element 5. The second anchor element 22 also has several lateral bores 17, R.414685

[0047] - 7 - whereby additional gaseous medium is guided to the outside of the anchor 2 and to the outside of the closing element 5, whereby in the open state of the gas injector gaseous medium can be guided on the outside of the closing element 5 on the one hand and on the other hand through the central opening 50 in the closing element 5 to the through openings 8 in the sealing seat component 7.

[0048] A first guide area 11 is formed on the outer circumference of the first anchor element 21, which guides the first anchor element 21 in the valve sleeve 13. A second guide area 12 is formed on the second anchor element 22, which guides the second anchor element 22 in the valve sleeve 13.

[0049] A conical contact area 23 is formed between the anchor element 21 and the second anchor element 22. As shown in Figure 3, the first anchor element 21 has a first conical surface 21a and the second anchor element 22 has a second conical surface 22a. The cone angle of both conical surfaces 21a and 22a is the same. The conical contact area 23 opens towards the sealing seat 6.

[0050] Furthermore, a hinged bearing 24 is provided between the first anchor element 21 and the second anchor element 22. This can be seen in detail in Figure 3. The hinged bearing 24 comprises a cylindrical section 25, which is formed on the first anchor element 21, and an arcuate section 26, which is arranged on the second anchor element 22. The arcuate section 26 is preferably a partial spherical segment.

[0051] As can be seen further in Figure 3, an annular gap 27 is provided in the axial direction between the articulated bearing 24 and the conical contact area 23. The annular gap 27 ensures the articulated bearing between the two anchor elements 21, 22 even when the first anchor element 21 is close to contacting the second anchor element 22 at the conical contact area 23. Furthermore, a buffer space 28 is formed at an end face 22b of the second anchor element 22 in relation to the first anchor element 21. The articulated bearing 24 between the two anchor elements 21, 22 can thus be realized by simple geometric components on the first and second anchor elements. R.414685

[0052] - 8 -

[0053] The cone angle of the conical contact area 23 to the central axis XX is preferably < 20°, particularly < 15° and more preferably < 10°. The cone angle is particularly preferably between 10° and 20°.

[0054] An annular gap 29 is formed on the outer circumference of the anchor 2 between the first and the second anchor element when the two anchor elements are in contact at the contact area 23.

[0055] Furthermore, the first armature element 21, which is directed towards the inner pole 3, has a first stop surface 21b which, when the magnetic actuator is activated, comes into contact with a second stop surface 3b on the inner pole 3. That is, when the magnetic actuator is activated, the first armature element 21 is pulled towards the inner pole 3 and strikes the second stop surface 3b.

[0056] Since the first armature element 21 is freely movable relative to the second armature element 22, it can be ensured that, upon activation of the magnetic actuator, the first armature element 21 makes full contact with the inner pole 3. In particular, the division of the armature into two parts prevents the first armature element 21 from tilting and thus from striking the inner pole 3 at an angle.

[0057] Since the second armature element 22, like the first armature element 21, is made of a magnetic material, it is also attracted towards the inner pole 3 during the opening process, albeit with a minimal time delay, so that the first armature element 21 can be briefly detached from the second armature element 22 during the opening process. As soon as the first armature element 21 is in contact with the inner pole 3 during the opening process, the second armature element 22 immediately comes back into contact with the first armature element 21 at the conical contact area 23.

[0058] Figures 1 to 3 show the closed state of the gas injector 1. To return to the closed position after an opening process, the gas injector 1 has a return element 9 in the form of a cylindrical spring. The return element 9 is in contact at one end with the first anchor element 21 and at the other end with an adjusting sleeve 15. R.414685

[0059] - 9 -

[0060] The adjusting sleeve 15 is fixedly arranged inside the inner pole 3, preferably by means of a press fit. Depending on how deeply the adjusting sleeve 15 is inserted into the interior of the inner pole 3 in the direction of the central axis XX, a preload of the return element 9 can be set. A shoulder 21c is provided on the first armature element 21 to receive the return element 9.

[0061] As can be seen in Figure 2, a first center of gravity S1 of the first anchor element 21 and a second center of gravity S2 of the second anchor element 22 are arranged on the central axis XX. The overall center of gravity SO of the anchor 2 is therefore also arranged on the central axis XX. As can be seen in Figure 2, the overall center of gravity SO is located closer to the sealing seat 6 than the first center of gravity S1 and the second center of gravity S2. This central arrangement of the overall center of gravity SO of the two moving masses of the anchor 2 thus results in improved dynamic behavior.

[0062] As can be seen in Figure 2, the first center of gravity S1 is located in the direction of the central axis XX at the level of the first guide area 11. The second center of gravity S2 is located in the direction of the central axis XX at the level of the second guide area 12. This measure also results in improved dynamic behavior of the anchor during the opening and closing processes.

[0063] Preferably, the center of gravity S1 of the first anchor element 21, the center of gravity S2 of the second anchor element 22, and the overall center of gravity SO of the anchor 2 are located in the region of the second anchor element. Thus, the individual centers of gravity of the two components of the anchor and the overall center of gravity of the anchor are very close to each other in the axial direction of the gas injector.

[0064] The mass of the first anchor element 21 is significantly less than the mass of the second anchor element 22. Preferably, the mass of the first anchor element is less than half the mass of the second anchor element. R.414685

[0065] - 10 -

[0066] The function of the gas injector 1 is as follows: starting from the closed state shown in Figures 1 to 3, in which an armature gap 14 exists between the first armature element 21 of the armature 2 and the inner pole 3 (see Figure 2), the coil 4 of the magnetic actuator 20 is energized. This attracts the armature 2 towards the inner pole 3. Since the armature 2 is designed in two parts and the first armature element 21 has a significantly lower mass than the second armature element 22, the first armature element 21 is attracted to the inner pole 3 first. This reduces the abrupt impulse when the first armature element 21 strikes the inner pole 3. This, in particular, extends the service life of the armature and inner pole components. The overall stress on the contact surfaces between the armature and inner pole is also reduced, thus protecting the components.In the fully open state, this results in a uniform surface pressure between the inner pole 3 and the first armature element 21.

[0067] Since the second anchor element 22 is also made of magnetically active material, during the opening process, the second anchor element 22 is also pulled immediately after the first anchor element 21 is pulled, at which point it is no longer in contact with the first anchor element. This allows the closing element 5 to be quickly lifted from the sealing seat 6, which is firmly connected to the second anchor element 22. Because the movement of the second anchor element 22 begins immediately after the movement of the first anchor element 21, there is practically no delay in the opening process at the sealing seat 6 during operation.

[0068] Furthermore, due to the articulated mounting 24 between the first and second anchor elements 21, 22, no critical flexing or rolling movements occur between the two anchor elements when the second anchor element 22 comes back into contact with the first anchor element 21, which is then in contact with the inner pole 3.

[0069] The articulated bearing 24 between the first and second anchor elements 21, 22 also enables optimal adaptation of the anchor components to changing dynamic conditions. R.414685

[0070] - 11 -

[0071] Furthermore, the two-part design of the anchor prevents undesirable movement of the second anchor element 22 at the sealing seat 6 during the opening process. Additionally, the conical contact area 23 ensures that a three times larger contact surface is formed between the first anchor element 21 and the second anchor element 22 compared to an annular contact surface.

[0072] Preferably, the first center of mass S1 and the second center of mass S2 are located in the inner area of ​​the guide surfaces of the anchor elements 21, 22, and in particular in the area of ​​the second anchor element 22. This results in a small offset of the centers of mass S1, S2 in the direction of the central axis XX, thereby achieving reliable opening and closing behavior of the gas injector.

[0073] During the closing process, the coil 4 of the magnetic actuator 20 is no longer energized, so that a rapid closing process is achieved by the weight of the armature 2 and the return element 9. The first armature element 21 and the second armature element 22 are each guided separately on their respective guide areas 11 and 12. The conical contact area 23 between the armature elements ensures centering between the two armature elements even during the closing process.

[0074] The overall center of gravity SO is also located in the area of ​​the second anchor element 22 (compare Figure 2).

[0075] The gas injector 1 according to the invention can thus be used for injecting a wide variety of gaseous media, in particular natural gas, hydrogen, methane, ammonia, CNG, urea, etc. In the closed state, the elastomer sealing element 10 provides a reliable seal at the sealing seat 6.

Claims

R.414685 - 12 - Claims 1. Gas injector for injecting a gaseous medium, comprising: - a magnetic actuator (20) comprising an armature (2), an inner pole (3) and a coil (4), and - a closing element (5) which opens and closes a through-opening (8) at a sealing seat (6), - wherein the anchor (2) is formed in two parts with a first anchor element (21) and a second anchor element (22), - wherein the first anchor element (21) is directed towards the inner pole (3) and has a first stop surface (21 b) for contact with a second stop surface (3b) of the inner pole (3), - wherein the locking element (5) is firmly connected to the second anchor part (22), - wherein the first anchor element (21) and the second anchor element (22) are loosely joined together and - wherein a conical contact area (23) is formed between the first anchor element (21) and the second anchor element (22).

2. Gas injector according to claim 1, wherein the mass of the first anchor element is smaller than the mass of the second anchor element.

3. Gas injector according to one of the preceding claims, wherein the anchor (2) has a hinged bearing (24) between the first anchor element (21) and the second anchor element (22).

4. Gas injector according to one of the preceding claims, wherein the first anchor element (21) is guided on a first guide area (11) and the second anchor element (22) is guided on a second guide area (12).

5. Gas injector according to one of the preceding claims, further comprising a reset element (9) which is used to reset the armature (2) R.414685 - 13 - is set up from an open to a closed starting position, with the reset element (9) engaging the first anchor element (21).

6. Gas injector according to one of the preceding claims, wherein a first center of gravity (S1) of the first anchor element (21) and a second center of gravity (S2) of the second anchor element (22) are located on a central axis (XX) of the gas injector.

7. Gas injector according to claim 6, wherein an overall center of gravity (SO) of the armature (2) lies on the central axis (XX) of the gas injector.

8. Gas injector according to claim 7, wherein the overall center of gravity (SO) is closer to the sealing seat (6) than the first center of gravity (S1) and the second center of gravity (S2).

9. Gas injector according to claim 7 or 8, wherein the overall center of gravity (SO), the first center of gravity (S1) and the second center of gravity (S2) are located in the region of the second anchor element (22).

10. Gas injector according to one of the preceding claims, wherein the armature (2) and the closing element (5) have openings for supplying the gaseous medium.

11. Gas injector according to one of the preceding claims, wherein the sealing seat (6) is formed in an annular shape between the closing element (5) and a sealing seat component (7).

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