Gas injector with reduced temperature at seal seat

Abstract

The invention relates to a gas injector for blowing in a gaseous medium, in particular hydrogen, comprising: a closing element (2) which releases and closes a through-opening (3) on a sealing seat (4) of a valve body (6), the closing element (2) comprising a valve needle (20) and a valve disk (21); an actuator (5) for actuating the closing element (2); a plurality of cooling ribs (7; 71; 72) which are arranged downstream of the sealing seat (4) in the flow direction of the gas injector.

Description

Technical Field

[0001] The invention relates to a gas injector for injecting gaseous fuel, such as hydrogen or methane, directly into a combustion chamber of an internal combustion engine, the gas injector having a measure for reducing the temperature at its sealing seat. Background Art

[0002] Gas injectors are known from the prior art in different configurations. The technical requirements for gas injectors are significantly different compared to fuel injectors for liquid fuels. In particular, in addition to the lack of lubrication achieved by liquid fuels, there is also the problem that the volume of the gaseous medium is significantly larger. As a result, problems may arise with regard to the precise metering for the injection process. In addition, high temperatures are generated during operation, especially in the area of ​​the sealing area between the closing element and the valve seat of the gas injector. Since the combustion gas may reach the sealing area between the closing element and the valve seat during operation, increased temperatures may occur in the sealing area, which leads to increased wear of the components and possible increased deformation (Verzug). As a result, leakage may occur, especially in the area of ​​the valve seat. Summary of the invention

[0003] In contrast, the gas injector according to the invention for injecting gaseous media, in particular for injecting gaseous hydrogen, with the features of claim 1 has the advantage that the heat input to the components by the combustion gas can be reduced by utilizing the temperature reduction of the combustion gas itself during the injection process. Due to the cooling effect caused by the expansion, which is present to a large extent, in particular in the case of a supersonic outflow from the gas injector, a large temperature reduction potential is obtained, which can be utilized according to the invention. As a result, the valve seat wear at the sealing seat is reduced, so that the necessary sealing requirements can be met throughout the service life of the gas injector in both operating and stationary conditions. For example, in the stationary state, if the combustion gas enters the exhaust system or the intake system of the internal combustion engine, there may be an explosion risk. In addition, the wear on the valve disk due to high temperature loads can be reduced, so that the sealing seat is reliably sealed during the service life of the gas injector. According to the invention, this is achieved in that the gas injector comprises a closing element, which opens and closes the through-opening at the sealing seat of the valve body. In this case, the closing element comprises a valve needle and a valve disk, wherein the valve disk seals at the sealing seat. Furthermore, an actuator is provided for actuating the closing element. Furthermore, the gas injector comprises a plurality of cooling ribs which are arranged behind the sealing seat in the flow direction of the gas injector. The cooling ribs make it possible to utilize the temperature reduction of the combustion gas caused by the expansion of the combustion gas, since the flow cross section increases significantly behind the sealing seat of the gas injector. As a result, the region of the gas injector facing the combustion chamber is effectively cooled.

[0004] At a gas inflow temperature of approximately 30° C., very low gas temperatures of up to approximately −150° C. can be achieved locally. This cooling potential can be utilized by using cooling ribs on the gas injector in a convective manner, which are preferably arranged in the coldest outflow region of the combustion gas. This reduces the temperature of the components of the gas injector, in particular the valve disk and the valve body, which are directed toward the combustion chamber and are directly exposed to the hot combustion chamber gases.

[0005] The dependent claims reveal preferred developments of the invention.

[0006] Preferably, the cooling ribs are formed on the valve disk. The cooling ribs are preferably arranged on the outer circumference of the valve disk and protrude radially. Thus, when the gas injector is open, the combustion gas flows through the intermediate region between the cooling ribs and cools them in particular, which in turn cool the valve disk. Since a part of the sealing seat of the gas injector is located on the valve disk, the sealing seat is also cooled accordingly.

[0007] Further preferably, cooling ribs are arranged on the valve body of the gas injector. Since the second part of the sealing seat of the gas injector is located on the valve body, a cooling effect is also produced here, thereby reducing component wear of the sealing seat of the gas injector.

[0008] Preferably, cooling ribs are formed both on the valve disk and on the valve body, so that both components can be cooled simultaneously in the region of the sealing seat, which is formed between the two components.

[0009] Preferably, the cooling ribs are arranged on the additional component. As a result, the components of the valve disc and the valve body forming the sealing seat can be designed geometrically optimized for reliable sealing, and cooling can be achieved by means of the additional component. The additional component is preferably arranged on the valve disc and / or the valve body.

[0010] It is further preferred that the additional component comprises a core region. The core region may be hollow and have a vacuum, or be filled with nitrogen or other gases, or alternatively, the core region has an insert.

[0011] According to another preferred embodiment of the invention, the additional component is a component with high porosity. Due to the high porosity, the surface area of ​​the additional component can be increased, so that in combination with the cooling ribs a very large surface can be provided, which can cool the valve disk and / or the valve body. The additional component is preferably a sintered component.

[0012] Further preferably, an insulating layer is provided on the valve disk and / or the valve body. Here, this layer is preferably configured completely on the valve disk on the side directed toward the combustion chamber.

[0013] The insulating layer is preferably arranged on regions of the gas injector which are not formed with cooling ribs.

[0014] Preferably, the insulating layer is also arranged on the cooling ribs.

[0015] Further preferably, the insulating layer is also arranged on the valve body. The insulating layer is preferably applied by material bonding, for example by means of welding or flame spraying, etc. Preferably, a phase change material is also used, which can absorb a relatively large amount of heat by phase change in the combustion chamber of the internal combustion engine during the highest temperature range.

[0016] In addition to the integrally bonded connection, the additional component can also be fastened to the valve disk and / or the valve body by means of a force-locking connection.

[0017] Further preferably, the additional component comprises a shielding element, which is arranged on the side of the valve disc pointing toward the combustion chamber. The shielding element protects the valve disc from heat from the combustion chamber. The shielding element is preferably connected to the valve disc by means of a material-locking connection, such as welding. An insulating layer or a hollow area, etc., as described above, can also be provided on the shielding element.

[0018] Further preferably, the gas injector comprises a jet forming cap, which is arranged on the valve disc in order to shape and define the blow-in jet of the combustion gas into the combustion chamber. The jet forming cap can thus predetermine a preferred jet shape in the combustion chamber in order to support an optimized ignition in the combustion chamber. Another advantage of the jet forming cap is that the blow-in jet can be adapted individually to different internal combustion engines, for example internal combustion engines of different manufacturers. This results in the advantage that the gas injector can be manufactured as a mass component, and the blow-in jet can then be adapted in a user-specific manner by the jet forming cap.

[0019] Preferably, the cooling ribs extend parallel to the central axis of the gas injector. The intermediate spaces between adjacent cooling ribs are preferably open in the direction of the combustion chamber.

[0020] The gas injector is preferably an outwardly opening injector in which, due to the proximity to the combustion chamber during direct injection, temperature issues are of great significance.

[0021] Preferably, the gas injector also has a first needle guide and a second needle guide for the closing element. In this case, the first needle guide is located further away from the sealing seat in the axial direction than the second needle guide. The second needle guide is therefore arranged close to the valve disk and can also be protected from high combustion chamber temperatures by the invention. As a result, the guiding properties of the gas injector during opening and closing are very good over its entire service life, so that the planned injection amount can always be reliably achieved.

[0022] According to a preferred embodiment of the invention, the valve disk and the valve needle of the closing element are constructed in one piece. This has the advantage, among other things, that the valve disk does not have to be connected to the valve needle by a welding connection or the like, since an incorrectly arranged welding connection could result in deformations at the valve disk and thus in a non-tight seal at the sealing seat.

[0023] Furthermore, the invention relates to an internal combustion engine, in particular an internal combustion engine of a vehicle, which has a gas injector according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the accompanying drawings:

[0025] Figure 1 A schematic cross-sectional view showing a gas injector in a closed state according to a first preferred embodiment of the present invention,

[0026] Figure 2 Show Figure 1 A schematic cross-sectional view of the sealing seat of the gas injector in the open state,

[0027] Figure 3 Show Figure 2 A schematic cross-sectional view of the combustion chamber side end of the gas injector along line III-III,

[0028] Figure 4 A schematic partial cross-sectional view showing a combustion chamber side end portion of a gas injector according to a second embodiment of the present invention,

[0029] Figure 5 Shown along Figure 4 A schematic cross-sectional view of line VV of FIG.

[0030] Figure 6 A schematic partial cross-sectional view showing a combustion chamber side of a gas injector according to a third embodiment of the present invention,

[0031] Figure 7 Shown along Figure 6 A schematic cross-sectional view of line VII-VII of FIG.

[0032] Figure 8 A schematic partial cross-sectional view showing a combustion chamber side of a gas injector according to a fourth embodiment of the present invention,

[0033] Fig. 9 A schematic partial cross-sectional view showing a combustion chamber side of a gas injector according to a fifth embodiment of the present invention,

[0034] Fig.10 A schematic partial cross-sectional view showing a combustion chamber side of a gas injector according to a sixth embodiment of the present invention,

[0035] Fig.11 A schematic partial cross-sectional view showing a combustion chamber side of a gas injector according to a seventh embodiment of the present invention,

[0036] Fig.12 Shown along Fig.11 A schematic cross-sectional view of line XII-XII of FIG.

[0037] Fig.13 A schematic partial cross-sectional view showing a combustion chamber side of a gas injector according to an eighth embodiment of the present invention. DETAILED DESCRIPTION

[0038] Below, refer to Figure 1 and Figure 2 A gas injector 1 according to a first preferred embodiment of the present invention will be described in detail.

[0039] like Figure 1 As shown, a gas injector 1 for injecting a gaseous medium, in particular gaseous hydrogen, comprises a closing element 2 and an actuator 5 .

[0040] The closing element 2 releases and closes the through-opening 3 at the sealing seat 4. The resetting element 8 resets the closing element 2 to the closed initial position. Figure 1 The closed initial position is shown, from which the opening process of the gas injector 1 takes place.

[0041] The closing element 2 comprises a valve needle 20 and a valve disk 21. In this case, the valve needle 20 extends through the gas injector 1 in an axial direction XX.

[0042] The sealing seat 4 is formed between the valve disk 21 and the valve body 6. Here, the closing element 2 is a closing element that opens outwards. The closing element 2 also includes two needle guides 22, which guide the closing element in the valve body 6.

[0043] In this embodiment, the actuator 5 is an electromagnetic actuator and comprises an armature 50 which can be moved in the axial direction XX of the gas injector in order to move the closing element 2 from Figure 1 The closed position shown in Figure 2 in the open position shown in .

[0044] A spring disk 23 is also arranged on the closing element 2, on which a reset element 8 is supported, which is used to reset the closing element 2 into the closed position. The reset element 8 is a cylindrical spring, which is supported between the spring disk 23 and a shoulder 80 on the valve body 6.

[0045] The gas injector 1 further comprises a plurality of cooling ribs 7 which are arranged behind the sealing seat 4 in the flow direction through the gas injector. In this exemplary embodiment, the cooling ribs 7 are arranged only on the closing element 2. More precisely, the cooling ribs 7 are arranged on the valve disk 21 along the outer circumference of the valve disk 21. The cooling ribs are integrally formed with the valve disk 21 and are open in the direction of the combustion chamber 10. In this case, when the gas injector is open, the gas flow can be as follows: Figure 2 As shown, the flow passes between the cooling ribs 7 .

[0046] from Figure 3 It can be seen from the sectional view of that the cooling ribs 7 are uniformly configured on the combustion chamber side end of the valve disc 21 along the outer circumference of the valve disc 21. Here, the cooling ribs 7 extend from the conical part of the valve disc 21 to the combustion chamber side end of the valve disc 21.

[0047] As a result, the combustion gases have already expanded to a great extent in the region of the valve disk 21 due to the volume increase caused by the intermediate regions 7a between the cooling ribs 7. Due to the expansion of the combustion gases, a cooling effect on the combustion gases is obtained, which is transmitted to the surrounding components, in particular to the cooling ribs 7 and the intermediate regions 7a, by convection. As a result, a temperature reduction of the valve disk 21 is obtained, in particular also in the region of the sealing seat 4, whereby excessive wear at the sealing seat can be avoided during operation of the gas injector.

[0048] Therefore, when the gas injector 1 is in operation, a temperature reduction can be achieved at the sealing seat 4, which significantly reduces the temperature load of the components at the sealing seat 4. As a result, the gas injector can be arranged as close as possible to the combustion chamber 10 of the internal combustion engine, so that the gaseous fuel can be injected directly into the combustion chamber.

[0049] exist Figure 1 In FIG. 1 , the gas feed through the gas injector 1 is indicated by arrow A. Arrow B schematically indicates the outflow of the combustion gas from the gas injector, wherein, due to the shape of the valve disk 21 , a hollow-conical spray is produced which is blown into the combustion chamber 10 .

[0050] Figure 4 and Figure 5 A gas injector 1 according to a second preferred embodiment of the invention is shown. Components which are identical or have the same function as in the first embodiment are denoted by the same reference numerals.

[0051] like Figure 4 and Figure 5 As shown, in the second embodiment, the cooling ribs 71 are arranged only on the valve body 6. The valve plate 21 has no cooling ribs. Here, the cooling ribs 71 on the valve body 6 are arranged in such a way that they enable a flow from the inside to the outside at the combustion chamber-side end of the valve body 6. Therefore, in the top view of the valve body 6 ( Figure 5), a toothed structure is obtained, wherein the cooling ribs 71 are designed to be relatively thin, so as to provide the largest possible opening cross section through the intermediate spaces between the cooling ribs 71. This embodiment is particularly suitable for blowing in large gas quantities. In other respects, this embodiment corresponds to the first embodiment, so that reference can be made to the description given there.

[0052] Figure 6 and Figure 7 A gas injector according to a third embodiment of the invention is shown. Components which are identical or have the same function as in the previous embodiments are again denoted by the same reference numerals.

[0053] like Figure 6 As shown, in the third embodiment, the cooling ribs 72 are arranged on the additional component 11. The additional component 11 is fixed to the valve body 6 by means of a welded connection 12. The additional component 11 has a core area 11a and a peripheral area 11b. The cooling ribs 72 are constructed between the core area 11a and the peripheral area 11b. Here, the additional component 11 is preferably constructed in one piece.

[0054] Thus, when the gaseous fuel flows out at the combustion chamber-side end of the gas injector, the additional component 11 reduces the temperature. In this case, the valve body 6 is cooled better in particular because it is directly connected to the additional component 11. The additional component 11 of this embodiment is a gasket. However, it should be noted that the geometry of the additional component 11 can also be configured differently. In other respects, this embodiment corresponds to the previous embodiment, so that reference can be made to the description given there.

[0055] Figure 8 A gas injector 1 according to a fifth embodiment of the invention is shown. Components which are identical or have the same function as in the previous embodiments are denoted by the same reference numerals.

[0056] like Figure 8 As shown, the fifth embodiment corresponds essentially to the third embodiment, wherein the cooling ribs 71 are arranged on the valve body 6. In addition, an additional component 11 is provided on the valve disk 21 at the closing element 2. The additional component 11 comprises a pot-shaped housing 13, which is welded to the combustion chamber side end of the valve disk 21. A cavity 14 is provided between the pot-shaped housing 13 and the valve disk 21. The cavity 14 is used for insulation and can be constructed as a vacuum, for example, or filled with a gas, such as nitrogen or air. Alternatively, the cavity 14 can also be filled with a porous material or other material with good insulation properties. Therefore, in the fifth embodiment, on the one hand, the cooling of the valve body 6 is achieved by the cooling ribs 71, and on the other hand, excessive heat input into the closing element 2 is prevented by the additional component 11 having the cavity 14. In other respects, this embodiment corresponds to the previous embodiment, so reference can be made to the description given there.

[0057] Fig. 9 A gas injector 1 according to a fifth embodiment of the invention is shown. Components which are identical or have the same function as in the previous embodiments are denoted by the same reference numerals.

[0058] like Fig. 9 As shown, an additional component 15 is provided on the valve disk 21 at the closing element 2, which additional component is made of a material with a high porosity. The additional component 15 is, for example, a sintered metal. The additional component 15 covers the entire surface of the valve disk 21 pointing in the direction of the combustion chamber 10. As a result, the thermal resistance on the side of the valve disk 21 pointing in the direction of the combustion chamber is increased. As a result, the thermal load of the valve disk 21 in the area of ​​the sealing seat 4 is reduced. Figure 5 and Figure 8 Similarly to the embodiment of the present invention, cooling ribs 71 are provided on the valve body 6. Since the additional component 15 is also located in the expansion area of ​​the gaseous fuel to be injected, like the cooling ribs 71, a cooling effect is also obtained on the additional component 15 and the valve disk 21. In other respects, this embodiment corresponds to the previous embodiment, so reference can be made to the description given there.

[0059] Fig.10 A gas injector 1 according to a sixth embodiment of the invention is shown. Components which are identical or have the same function as in the previous embodiments are denoted by the same reference numerals.

[0060] like Fig.10 As shown, the gas injector of the sixth exemplary embodiment has a shielding element 16 as an additional component, which is fastened to the side of the valve disk 21 pointing toward the combustion chamber. The shielding element 16 is fastened to the valve disk 21 by means of a welded connection 17. The shielding element 16 protects the valve disk 21 from very high temperatures from the combustion chamber 10. Figure 5 , Figure 8 and Fig. 9 As in the embodiment of the present invention, cooling ribs 71 are formed on the valve body 6. The shielding element 16 is designed in a mushroom shape and has a flat shielding part and a foot part for connecting to the valve disk 21, the diameter of which corresponds to the maximum diameter of the valve disk 21. In other respects, this embodiment corresponds to the previous embodiment, so reference can be made to the description given there.

[0061] Fig.11 and Fig.12 A gas injector 1 according to a seventh embodiment of the invention is shown. Components which are identical or have the same function as in the previous embodiments are again denoted by the same reference numerals.

[0062] like Fig.11As shown, the gas injector of the seventh embodiment has an additional component 18, which has an open hollow area 18a. The hollow area 18a is open on four sides toward the combustion chamber 10 (see Fig.12 ). The hollow area 18a thus has a cross shape. Here, the additional component 18 with the hollow area also serves to shield the valve disc 21 in order to reduce the temperature of the valve disc 21 during operation. Here, the additional component 18 completely covers the surface of the valve disc 21 that is directed toward the combustion chamber. This measure for reducing the temperature at the valve disc 21 has the advantage, in particular, that it can be realized simply and cost-effectively. In other respects, this embodiment corresponds to the previous embodiment, so reference can be made to the description given there.

[0063] Fig.13 A gas injector 1 according to an eighth embodiment of the invention is shown. Components which are identical or have the same function as in the previous embodiments are denoted by the same reference numerals.

[0064] like Fig.13 As shown, the gas injector 1 of the eighth embodiment has cooling ribs 7 on the valve disk 21 and cooling ribs 71 on the valve body 6. Therefore, the temperature can be reduced simultaneously on the valve disk 21 and the valve body 6 by the expanding gaseous fuel. Therefore, a particularly good temperature protection of the sealing seat 4 between the valve disk 21 and the valve body 6 is achieved. In addition, an insulating layer 9 is also provided on the side of the valve disk 21 pointing toward the combustion chamber 10. The insulating layer 9 insulates the valve disk 21 from the hot combustion gas from the combustion chamber 10.

[0065] It should be noted that, in all the above-mentioned embodiments, such an insulating layer 9 can also be provided on the valve disk 21 or an additional component.

[0066] Therefore, in the eighth embodiment, the heat resistance of the components of the gas injector directed toward the combustion chamber can be significantly improved by doubly arranging cooling ribs on the valve disk 21 and the valve body 6. In other respects, this embodiment corresponds to the previous embodiment, so reference can be made to the description given there.

[0067] For all the described embodiments, it should be noted that any combination of the features shown in these embodiments is possible. In particular, in order to be able to achieve insulation with respect to the combustion chamber, an insulating layer can always be provided on the valve disk 21 and / or on the valve body 6 or, if present, on the additional component. In addition, in all embodiments, a shielding element can also be provided on the valve disk 21 or on the additional component. In this case, the shielding element can also have a hollow area that is sealed and filled with a vacuum or gas or filled with a solid material, in particular a sintered material. In all embodiments, the cooling ribs can be provided either only on the valve disk 21, only on the valve body 6, or on both components.

Claims

1. A gas injector for blowing a gaseous medium, the gaseous medium being in particular hydrogen, the gas injector comprising: a closing element (2) which releases and closes a through-opening (3) at a sealing seat (4) of a valve body (6), wherein the closing element (2) comprises a valve needle (20) and a valve disk (21); an actuator (5) for operating the closing element (2); A plurality of cooling ribs (7; 71; 72) are arranged behind the sealing seat (4) along the flow direction of the gas injector.

2. The gas injector according to claim 1, wherein: The cooling ribs (7; 71; 72) are arranged on the valve disk (21) and / or the valve body (6).

3. The gas injector according to claim 1, wherein: The cooling ribs (72) are arranged on an additional component (11), wherein the additional component (11) is arranged on the valve body (6) and / or the valve disk (21).

4. The gas injector according to claim 3, wherein: The additional component has a core region (11a) which is hollow and filled with a vacuum or a gas, or which is filled with an insert.

5. The gas injector according to claim 3 or 4, wherein: The additional component has a high porosity and is in particular a sintered component.

6. A gas injector according to any one of the preceding claims, wherein: An insulating layer (9) is arranged on the valve disk (21) and / or the valve body (6), the insulating layer being directed toward the combustion chamber (10).

7. The gas injector according to any one of claims 3 to 6, wherein: The additional component comprises a shielding element (16), which is arranged on a side of the valve disk (21) pointing toward the combustion chamber (10) and shields the valve disk from heat coming from the combustion chamber (10).

8. The gas injector according to claim 1, further comprising a jet forming cap which is arranged on the valve disk (21) in order to form a blowing jet (B) into the combustion chamber (10).

9. The gas injector according to any one of the preceding claims, wherein: The closing element is a closing element that opens outward.

10. The gas injector according to any one of the preceding claims, wherein: The cooling ribs extend parallel to a centre axis (XX) of the gas injector.

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