Fuel Injection Valve

Abstract

To create a fuel injection valve of a new type, reduced in leakage of both of a fuel and a coolant.SOLUTION: An outer seal surface (25) and at least one inner seal surface (26) separated from the outer seal surface (25) by at least one recessed portion (24), are formed on an end surface (11a) of a nozzle body (11) and / or an end surface (12a) of a nozzle holder (12), that is, the end surface (12a) adjacent to the end surface (11a) of the nozzle body (11), each inner seal surface (26) seals a fuel supply line (15) communicated therewith in a region of the end surfaces adjacent to each other, and each outer seal surface (25) seals a coolant supply line (22) and a coolant discharge line (23) communicated therewith in a region of the end surfaces adjacent to each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The invention relates to a fuel injection valve as claimed in claim 1. [Background technology]

[0002] From DE 10 2004 013 A1 a fuel injection valve for an internal combustion engine is known. Thus, Patent Document 1 discloses a fuel injector having a nozzle body, a nozzle holder and a clamp nut, the nozzle body and the nozzle holder being axially clamped together via the clamp nut. The nozzle body accommodates a nozzle needle, in which at least one fuel supply line is led, the fuel supply line opening into a pressure chamber for fuel in the nozzle body surrounding the nozzle needle. At least one fuel supply line is similarly mounted within the nozzle holder, the nozzle holder being axially clamped together with the nozzle body via a clamp nut, and the fuel supply line communicating with the fuel supply line of the nozzle body, i.e. directly, without an adapter between the nozzle holder and the nozzle body. The end faces of the nozzle body and nozzle holder of the fuel injection valve, which are placed in an overlapping state, are pressed against each other via the clamping nut as a result of the axial clamping, thereby providing a seal at the end faces which are placed in an overlapping state.

[0003] According to this document a recess is introduced into the end face of the nozzle body, as a result of which a radially outer sealing surface is formed at the end face of the nozzle body. This radially outer sealing surface seals the communicating fuel supply line in the region of the end faces of the nozzle body and nozzle holder. Any leakage of fuel that travels past this seal surface can reach the outside.

[0004] From DE 10 2004 0136 A1 a further fuel injector for an internal combustion engine is known. The fuel injector includes a union nut that receives a plurality of injection modules, namely, an injection head, a servo body, a transfer body, an adapter body, and a nozzle body, stacked on top of each other. The end face of the injection head is provided with recesses which define outer and inner sealing surfaces. The inner sealing surface seals the fuel carrying line against the recess in the end face. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] DE 19827268 A1 [Patent Document 2] German Patent Publication No. 19914720 Summary of the Invention [Problem to be solved by the invention]

[0006] In the case of cooled injectors, problems have arisen with the sealing of the fuel and coolant lines.

[0007] Starting from this, the invention is based on the object of creating a new type of fuel injector which reduces leakage of both fuel and coolant. [Means for solving the problem]

[0008] This object is solved through a fuel injector as claimed in claim 1. According to the invention, coolant supply lines and coolant discharge lines communicating with each other are introduced into the nozzle body, into the nozzle holder and into the optional adapter, and via the nozzle body coolant supply lines and coolant discharge lines coolant can be supplied to and discharged from the nozzle body in order to cool the nozzle body. an end face of the nozzle body and / or an end face of the nozzle holder or adapter adjacent the end face of the nozzle body is formed with an outer sealing surface and at least one inner sealing surface separated from the outer sealing surface by at least one recess; each inner sealing surface sealing a respective communicating fuel supply line in an area of ​​the adjacent end surface; Each outer sealing surface seals a respective communicating coolant line at the region of the adjacent end faces.

[0009] The fuel injector of the present invention provides separate and distinct sealing surfaces for sealing the fuel supply line and for sealing the coolant line. each inner sealing surface is separated from a respective outer sealing surface by at least one recess; The respective inner sealing surfaces seal against a fuel supply line and the respective outer sealing surfaces seal against a coolant line of an adjacent fuel injector assembly in the region of their respective adjacent end faces. Fuel leakage is trapped in the area of ​​the recess and cannot reach the outside via the respective outer sealing surface. Also, coolant leaks can migrate into or out of the respective recesses. This allows for particularly advantageous sealing of the fuel injector while reducing fuel and coolant leakage.

[0010] Preferably, each recess communicates in the region of the nozzle holder with a leakage drain, via which leakage collecting in the region of the recess can be drained. As a result, leakage collecting in the area of ​​the respective recess can be evacuated particularly advantageously away from the fuel injection valve.

[0011] According to a first version, the respective outer sealing surface and the respective inner sealing surface are separated by a common recess for fuel leakage and for coolant leakage. According to a second version, each outer sealing surface and each inner sealing surface are separated by separate recesses for fuel leakage and coolant leakage. The first version, which provides a common recess for fuel and coolant leaks, has a simplified design. The second version, which provides separate recesses for fuel and coolant leaks, is a more complex design but allows separate drainage of fuel and coolant leaks.

[0012] Preferred further developments of the invention emerge from the dependent claims and the following description. Exemplary embodiments of the invention will now be explained in more detail via the drawings, without being limiting thereto. [Brief description of the drawings]

[0013] [Figure 1] 2 is an axial cross-sectional view showing a fuel injection valve. [Diagram 2] FIG. 2 shows detail II of FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention relates to a fuel injection valve. FIG. 1 shows an axial section through a fuel injector 10 for an internal combustion engine. The fuel injector 10 of the exemplary embodiment shown in FIG. 1 comprises a nozzle body 11, a nozzle holder 12 and a clamp nut 13.

[0015] The nozzle body 11 houses a nozzle needle 14 . The nozzle needle 14 is guided axially movably in a recess in the nozzle body 11 . At least one fuel supply line 15 is led into the nozzle body 11 , via which fuel can be supplied to a pressure chamber 16 of the nozzle body 11 which partially surrounds the nozzle needle 14 .

[0016] The nozzle body 11 is axially clamped together with the nozzle holder 12 via a clamp nut 13, and at least one fuel supply line 17 is similarly introduced into the nozzle holder 12, and the fuel supply line 17 communicates with each of the fuel supply lines 15 of the nozzle body 11.

[0017] The nozzle holder 12 houses a spring 18 which supports itself at a first end on a disc spring 19 and at an opposite second end on a disc spring 20 . On the disc spring 20 a push rod 21 is formed which acts on the nozzle needle 14 and abuts against it.

[0018] The spring force provided by the spring element 18 is transmitted via the push rod 21 to the nozzle needle 14 and tends to close the nozzle body 11 via the nozzle needle 14 . Against this spring force provided by the spring element 18, the nozzle needle 14 can be moved axially, whereby the nozzle body 11 opens when the force dependent on the pressure in the pressure chamber 16 is greater than the spring force of the spring element 18.

[0019] In the exemplary embodiment shown, the nozzle body 11 and the nozzle holder 12 are clamped together directly in the axial direction via the clamping nut 13, so that the end face 11a of the nozzle body 11 and the end face 12a of the nozzle holder 12, which are positioned opposite each other, are placed in direct abutment against each other such that the fuel supply lines 15, 17 are in direct communication with each other.

[0020] In contrast to this, it is also possible to arrange an adapter (not shown) between the nozzle body 11 and the nozzle holder 12, so that the nozzle body 11 and the nozzle holder 12 are indirectly clamped together via a clamping nut 13, with the adapter in between, and the end face 11a of the nozzle body 11 being placed in sealed abutment against an adjacent first end face of the adapter, and the opposite second end face of the adapter being placed in sealed abutment against an end face 12a of the nozzle holder 12.

[0021] In particular, if such an adapter is present, at least one fuel supply line is obviously also introduced into this adapter, so that the respective fuel supply line 15 of the nozzle body 11 communicates with the respective fuel supply line 17 of the nozzle holder 12 indirectly, i.e. via a fuel supply line of the adapter, not shown, running therebetween.

[0022] FIG. 3 shows a cross section taken along line III-III of FIG. 1, and thus a view of the end face 11a of the nozzle body 11. As is clear from FIG. 3, two fuel supply lines 15 are introduced into the nozzle body 11, and fuel can be supplied to a pressure chamber 16 of the nozzle body 11 via the fuel supply lines 15. Therefore, two fuel supply lines are then also introduced into the nozzle holder 12 , the fuel supply lines in the nozzle holder 12 communicating directly or indirectly with the fuel supply line 15 of the nozzle body 11 .

[0023] Coolant supply lines and coolant discharge lines communicating with each other are also introduced between the nozzle body 11 and the nozzle holder 12 and, if an optional adapter is arranged between the nozzle body 11 and the nozzle holder 12, also in the adapter; FIG. 3 shows the coolant supply lines 22 and the coolant discharge lines 23 of the nozzle body 11 in the region of the end face 11a, at which end face coolant can be supplied to and discharged from the nozzle body 11 in order to cool the nozzle body 11.

[0024] These coolant lines 22, 23 in the nozzle body 11 communicate with corresponding coolant lines (not shown) in the nozzle holder 12 and, when an adapter is present, with corresponding coolant lines in the adapter.

[0025] In order to seal the fuel lines 15, 17 on the one hand and the coolant lines 22, 23 on the other hand in the region of the adjacent end faces, in the shown exemplary embodiment a recess 24 is introduced into the end face 11a of the nozzle body 11, which recess 24 separates an outer sealing surface 25 of the end face 11a from at least one inner sealing surface 26 of the end face 11a. In the illustrated exemplary embodiment of FIG. 3, there are two inner sealing surfaces 26 , which are separated from the outer sealing surface 25 by a recess 24 .

[0026] The inner sealing surfaces 26 of the end faces 11a seal the communicating fuel lines 15, 17 of the nozzle body 11 and nozzle holder 12, respectively, in the areas of the adjacent abutting end faces 11a, 12a. If fuel leakage were to occur in the area of ​​these inner seal faces 26, the fuel leakage would enter the area of ​​the recesses 24.

[0027] The outer sealing surface 25 of the end face 11a seals the communicating coolant lines 22, 23 in the area of ​​the adjacent and abutting end faces 11a, 12a of the nozzle body 11 and the nozzle holder 12, so that any leakage of coolant flowing through the outer sealing surface 25 can flow inward in the area of ​​the recess 24 on the one hand and outward in the direction of the clamping nut 13 on the other hand.

[0028] In the illustrated exemplary embodiment in which the nozzle body 11 and the nozzle holder 12 are clamped together directly axially without an adapter, the sealing surfaces 25, 26, i.e. the outer sealing surface 25 and the inner sealing surface 26, are formed on the end face 11a of the nozzle body 11. However, alternatively or additionally, it is also possible to form these sealing surfaces 25, 26 on the end face 12a of the nozzle holder 12. In order to reduce manufacturing costs, however, only the end face 11a of the nozzle body 11 is provided with the above-mentioned sealing surfaces 25, 26.

[0029] Thus, each inner sealing surface 26 seals a respective fuel supply line 15 , 17 against a respective recess 24 adjoining each inner sealing surface 26 . Fuel leakage will enter the area of ​​recess 24 .

[0030] Respective outer sealing surfaces 25 seal respective coolant lines 22, 23 against recesses 24 and outwardly. Thus, coolant leakage can also enter the area of ​​recess 24 .

[0031] In particular, as shown in FIG. 3, when a common recess is formed between the outer sealing surface 25 and the inner sealing surface 26, fuel leakage and coolant leakage can jointly enter the recess 24 and be discharged from the recess 24 to be drained through the leakage drain 27 without pressure.

[0032] The leakage drain 27 in this case extends radially outward beyond the push rod 21 into the area of ​​the nozzle holder 12, through a hole 28 in the valve body 20 along the spring element 18 in the direction of a hole 29 in the valve body 19, so that the leakage drain is discharged from the leakage drain via a leakage drain hole 30 out of the fuel injection valve 10.

[0033] Each inner sealing surface 26 is a high pressure sealing surface for a respective fuel supply line 15,17. The outer sealing surface 25 is the low pressure sealing surface for each of the coolant lines 22,23.

[0034] A region of each inner sealing surface 26 may be formed with an interlocking edge. Such mating edges are plastically deformed during clamping together of the assemblies which are clamped together axially via the clamping nut, thus increasing the sealing effect.

[0035] In the exemplary embodiment shown, a common recess 24 is provided for the fuel leak and the coolant leak, but in contrast to this it is also possible to introduce separate recesses in the region of the end face 11a which separates the outer sealing face 25 from the inner sealing face 26, The first recess serves to collect fuel leakage and the second recess serves to collect coolant leakage in order to drain these leakages separately from the fuel injector 10 via separate leakage drains.

[0036] In particular, in contrast to the illustrated exemplary embodiment, when an adapter is arranged between the nozzle body 11 and the nozzle holder 12, and thus the nozzle body 11 and the nozzle holder 12 are indirectly clamped together in the axial direction due to the interposition of the adapter, On the one hand, on the end face 11a of the nozzle body 11, and on the other hand, on the end face of the adapter which faces away from the nozzle body 11 and is intended to be placed in abutment against the end face 12a of the nozzle holder 12, can be provided to form sealing surfaces 25, 26 which will be described with reference to FIG.

[0037] The adapter is provided with sealing surfaces 25, 26 on both end surfaces thereof, which are positioned opposite each other. The end faces 11a, 12a of the nozzle body 11 and the nozzle holder 12, which are to be placed in abutment against the end faces of the adapter, can likewise be formed conventionally, i.e. without the recesses 24 which form the sealing surfaces 25, 26 and separate them from one another.

[0038] The recesses 28 shown in FIG. 3 are holes for receiving alignment pins that serve to align the nozzle body 11 and nozzle holder 12 during assembly so as to align the fuel lines 15, 17 and coolant lines 22, 23, which extend within the nozzle body 11 and nozzle holder 12, accurately and in a defined manner relative to one another.

[0039] The invention therefore proposes a coolant-cooled fuel injector, in which the fuel line and the coolant line are sealed via spatially and functionally separated sealing surfaces. Leakage of fuel into the surroundings is prevented. Fuel and coolant leaks can be vented in a defined manner. [Explanation of symbols]

[0040] 10...fuel injector, 11...nozzle body, 11a...end face, 12...nozzle holder, 12a...end face, 13...clamp nut, 14...nozzle needle, 15...fuel supply line, 16...pressure chamber, 17...fuel supply line, 22...coolant supply line, 23...coolant discharge line, 24...recess, 25...outer sealing surface, 26...inner sealing surface, 30...leakage drain

Claims

1. A fuel injection valve (10) for an internal combustion engine, comprising: a nozzle body (11) housing a nozzle needle (14), in which at least one fuel supply line (15) is introduced, said fuel supply line (15) opening into a pressure chamber (16) of said nozzle body (11) surrounding said nozzle needle (14) in cross section; a nozzle holder (12) into which at least one fuel supply line (17) is introduced, the fuel supply line (17) indirectly communicating with each of the fuel supply lines (15) of the nozzle body (11) via each of the fuel supply lines of an adapter; a clamp nut (13) that seals an end face (11a) of the nozzle body (11) and an end face (12a) of the nozzle holder (12), which are placed in an overlapping state via the adapter, and indirectly holds the nozzle body (11) and the nozzle holder (12) together in the axial direction via the clamp nut (13) via the adapter; having a coolant supply line (22) and a coolant discharge line (23) communicating with each other are introduced into the nozzle body (11), into the nozzle holder (12) and into the adapter, and a coolant for cooling the nozzle body (11) can be supplied to the nozzle body (11) and discharged from the nozzle body (11) via the coolant supply line (22) and the coolant discharge line (23); a first end face of the adapter directly adjacent to the end face (11a) of the nozzle body (11) and a second end face of the adapter directly adjacent to the end face (12a) of the nozzle holder (12) and positioned opposite the first end face, each of which is formed with an outer sealing surface (25) and at least one inner sealing surface (26) separated from the outer sealing surface (25) by at least one recess (24); each of the inner sealing surfaces (26) seals the fuel supply lines (15, 17) communicating with each other in a region of the end face (11a) of the nozzle body (11) and the end face (12a) of the nozzle holder (12) adjacent to each other via the adapter; each of the outer sealing surfaces (25) seals the coolant supply line (22) and the coolant discharge line (23) which communicate with each other in the region of the end face (11a) of the nozzle body (11) and the end face (12a) of the nozzle holder (12) adjacent to each other via the adapter. Fuel injection valve.

2. characterised in that each recess (24) communicates in the region of the nozzle holder (12) with a leakage drain (30) via which leakage collecting in the region of each recess (24) can be discharged from the fuel injection valve, 2. The fuel injection valve according to claim 1.

3. each said inner sealing surface (26) seals a respective one of said fuel supply lines (15, 17) against a respective one of said recesses (24) leading to said respective inner sealing surface (26), 3. A fuel injection valve according to claim 1 or 2.

4. each said outer sealing surface (25) seals each said coolant supply line (22) and said coolant discharge line (23) against and towards the outside of each said recess (24) which leads to each said outer sealing surface (25), A fuel injection valve according to any one of claims 1 to 3.

5. each said outer sealing surface (25) sealingly faces outwardly against each said recess (24) which is adjacent to said respective outer sealing surface (25), A fuel injection valve according to any one of claims 1 to 4.

6. characterised in that each of said outer sealing surfaces (25) and each of said inner sealing surfaces (26) are separated by a common recess (24) for fuel and coolant leakage. A fuel injection valve according to any one of claims 1 to 5.

7. each said outer sealing surface and each said inner sealing surface are separated by separate recesses for fuel leakage and coolant leakage, A fuel injection valve according to any one of claims 1 to 6.

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