Fuel injector of an internal combustion engine and internal combustion engine

Abstract

A fuel injector (10) of an internal combustion engine, which is designed to supply fuel to a combustion chamber of a cylinder of the internal combustion engine, comprising a first nozzle needle (14) which is movably guided in a first needle guide (12) and which interacts with first fuel injection openings (16) in such a way that the first nozzle needle (14), depending on its position, either allows or blocks a fuel flow of a first, relatively unignitable fuel through the first fuel injection openings (16), comprising a second nozzle needle (15) which is movably guided in a second needle guide (13) and which interacts with second fuel injection openings (17) in such a way that the second nozzle needle (15), depending on its position, either allows or blocks a fuel flow of a second, relatively ignitable fuel, which serves to ignite the first fuel, through the second fuel injection openings (17),wherein the first fuel injection openings (16) are arranged along a partial circle contour (18) and the second fuel injection openings (17) are arranged along a circular contour (19) such that a distance (x) between the center point (20) of the partial circle contour (18) and the center point (21) of the circular contour (19) is greater than the sum of the radius (r1) of the partial circle contour (18) and the radius (r2) of the circular contour (19), and wherein, in the installed state of the fuel injector, the second fuel injection openings (17) protrude deeper or further into a combustion chamber of the cylinder than the first fuel injection openings (16).

Description

[0001] The invention relates to a fuel injector of an internal combustion engine. Furthermore, the invention relates to an internal combustion engine with at least one fuel injector.

[0002] The present invention relates in particular to the field of so-called large engines or large internal combustion engines, whose cylinders have piston diameters of at least 140 mm, in particular of at least 175 mm. Such large internal combustion engines include, for example, marine engines.

[0003] Dual-fuel internal combustion engines are already known as marine engines. Dual-fuel internal combustion engines known from practice can be operated in a first operating mode, in which they burn a first fuel, in particular a relatively unignitable fuel, and in a second operating mode, in which they burn a second fuel, in particular a relatively ignitable fuel.

[0004] The first, relatively unignitable fuel can be, for example, methanol, ethanol, or ammonia. The second, relatively ignitable fuel can be, for example, diesel fuel. In the first operating mode, the first, relatively unignitable fuel, in particular methanol, ethanol, or ammonia, can be ignited by the second, relatively ignitable fuel, in particular diesel fuel.

[0005] DE 10 2013 000 048 B3 discloses a fuel injector by means of which, in the first operating mode of a dual-fuel internal combustion engine, both the first, relatively unignitable fuel and the second, relatively readily ignitable fuel can be introduced into the combustion chamber of a cylinder. The fuel injector disclosed therein is designed as a so-called double-needle injector, which has two nozzle needles that are movably guided in corresponding needle guides. First fuel injection openings that interact with a first nozzle needle and second fuel injection openings that interact with a second nozzle needle are each arranged along a circular contour, wherein, in the installed state of the fuel injector, the first fuel injection openings and the second fuel injection openings extend to the same depth or distance into the combustion chamber of the cylinder.This results in significant limitations in the injection of fuel into the combustion chamber of a cylinder, meaning that the combustion chamber cannot be used optimally. For example, if only relatively ignitable fuel is to be burned in a second operating mode, a significant portion of the combustion chamber's combustion chamber can no longer be filled with the relatively ignitable fuel.

[0006] Based on this, the present invention is based on the object of creating a novel fuel injector for an internal combustion engine and an internal combustion engine with such a fuel injector. This object is achieved by a fuel injector according to claim 1 and an internal combustion engine according to claim 7.

[0007] The fuel injector has a first nozzle needle which is movably guided in a first needle guide and which interacts with first fuel injection openings in such a way that the first nozzle needle, depending on its position, either releases or blocks a fuel flow of the first, relatively unignitable fuel through the first fuel injection openings.

[0008] The fuel injector further comprises a second nozzle needle which is movably guided in a second needle guide and which interacts with second fuel injection openings in such a way that the second nozzle needle, depending on its position, either releases or blocks a fuel flow of a second, relatively ignitable fuel, which serves to ignite the first fuel, through the second fuel injection openings.

[0009] The first fuel injection openings of the fuel injector are arranged along a partial circle contour and the second fuel injection openings are arranged along a circular contour such that a distance between the center of the partial circle contour and the center of the circular contour is greater than the sum of the radius of the partial circle contour and the radius of the circular contour.

[0010] When the fuel injector is installed, the second fuel injection ports extend deeper or further into the combustion chamber of the cylinder than the first fuel injection ports.

[0011] In the fuel injector according to the invention, it is provided that those fuel injection openings of the fuel injector which serve to introduce the relatively ignitable fuel into the combustion chamber of a cylinder protrude deeper or further into the combustion chamber of the cylinder when the fuel injector is installed than the first fuel injection openings which serve to introduce the relatively unignitable fuel into the combustion chamber of the cylinder. As a result, both the first, relatively unignitable fuel and the second, relatively ignitable fuel can be advantageously introduced into the combustion chamber, so that a combustion chamber of the combustion chamber can be optimally utilized. In particular, when, in a corresponding operating mode of the internal combustion engine, only relatively ignitable fuel is to be burned, the ignitable fuel can be optimally introduced into the combustion chamber.

[0012] Preferably, the partial circle contour on which the first fuel injection openings are arranged covers an angular range of 360°-δ, where δ is between 15° and 60°, in particular between 20° and 60°, preferably between 20° and 45°, and where the partial circle contour defined by the angle δ faces the circular contour on which the second fuel injection openings are arranged. The circular contour on which the second fuel injection openings are arranged covers an angular range of 360°. This allows for optimal introduction of both the first, relatively unignitable fuel and the second, relatively readily ignitable fuel into the combustion chamber of a cylinder.

[0013] Preferably, a ratio between a height offset of the circular contour on which the second fuel injection openings are arranged and the partial circle contour on which the first fuel injection openings are arranged, and the distance between the center of the partial circle contour and the center of the circular contour is between 0.1 and 0.4, in particular between 0.15 and 0.35, preferably between 0.17 and 0.29. This is also advantageous for the optimal introduction of the first, relatively unignitable fuel and the second, relatively ignitable fuel into the combustion chamber of the cylinder.

[0014] Preferably, the first fuel injection openings are configured to inject the first fuel into the combustion chamber in a first spray cone with a first cone angle, wherein the second fuel injection openings are configured to inject the second fuel into the combustion chamber in a second spray cone with a second cone angle, wherein the first cone angle is smaller than the second cone angle. The first cone angle is preferably between 66° and 88°, in particular between 68° and 86°, particularly preferably between 70° and 84°. The second cone angle is preferably between 70° and 92°, in particular between 72° and 90°, particularly preferably between 74° and 88°. This makes it possible to further improve the introduction of the first, relatively unignitable fuel and the second, relatively ignitable fuel into the combustion chamber of the respective cylinder.

[0015] Preferred developments of the invention will become apparent from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail, without being limited thereto, with reference to the drawings. Herein: Fig. 1: a schematic side view of a fuel injector according to the invention; Fig. 2: a bottom view of the fuel injector according to the invention; Fig. 3: a schematic cross section through the fuel injector according to the invention of the Fig. 1 .

[0016] The invention relates to a fuel injector of an internal combustion engine. Such a fuel injector is designed to supply fuel to a combustion chamber of a cylinder of the internal combustion engine. The fuel injector according to the invention serves to supply different fuels to an internal combustion engine, in particular designed as a dual-fuel internal combustion engine, for example, in a first operating mode, the introduction of a first, in particular relatively unignitable fuel, and a second, relatively ignitable fuel in order to ignite the first, relatively unignitable fuel via the second, relatively unignitable fuel in the first operating mode. Furthermore, in a second operating mode, in which exclusively the second, relatively unignitable fuel is combusted, the fuel injector is to inject the fuel into the combustion chamber of the cylinder.The first, relatively unignitable fuel can be methanol, ethanol, or ammonia. The second, relatively ignitable fuel is, in particular, diesel fuel.

[0017] Fig. 1 to 3 show different views of a fuel injector 10 according to the invention. The fuel injector 10 has a base body 11 which provides two needle guides 12, 13.

[0018] A first nozzle needle 14 is movably guided in a first needle guide 12, and a second nozzle needle 15 is movably guided in a second needle guide 13. First fuel injection openings 16 interact with the first nozzle needle 14 such that, depending on its position in the first needle guide 12, the first nozzle needle 14 either allows or blocks a fuel flow of a first, relatively unignitable fuel through the first fuel injection openings 16. Second fuel injection openings 17 interact with the second nozzle needle 15 such that, depending on its position in the second needle guide 13, the second nozzle needle 15 either allows or blocks a fuel flow of a second, relatively unignitable fuel through the second fuel injection openings 17.

[0019] Accordingly, if the internal combustion engine 10 is operated in an operating mode in which the first, relatively unignitable fuel is to be combusted and ignited with the aid of the second, relatively ignitable fuel, the first, relatively unignitable fuel is introduced into the combustion chamber of the cylinder via the first fuel injection openings 16 and the second, relatively ignitable fuel via the second fuel injection openings 17. If, in a second operating mode of the internal combustion engine, only the second, relatively unignitable fuel is to be combusted, the second fuel is introduced into the combustion chamber of the cylinder via the second fuel injection openings 17; the first fuel injection openings 16 are then permanently closed by the first nozzle needle 14.

[0020] The first fuel injection openings 16 are arranged along a partial circle contour 18, and the second fuel injection openings 17 are arranged along a circular contour 19. The partial circle contour 18 has a radius r1, and the circular contour 19 has a radius r2. A distance x between the center point 20 of the partial circle contour 18 and the center point 21 of the circular contour 19 is greater than the sum of the two radii r1 and r2.

[0021] The partial rice contour 18 and the circular contour 19 are therefore not arranged concentrically to each other and do not intersect.

[0022] In the installed state of the fuel injector 10, the second fuel injection openings 17 are arranged deeper or further in the combustion chamber of the cylinder than the first fuel injection openings 16. In Fig. 1the height offset h visualizes the distance of the plane of the partial circle contour 18 from the plane of the circular contour 19. The circular contour 19 with the second fuel injection openings 17 therefore projects, in the installed state of the fuel injector 10, deeper or further into the combustion chamber of the cylinder by the height offset h than the partial circle contour 18 with the first fuel injection openings 16.

[0023] The circular contour 19, on which the second fuel injection openings 17 are arranged, covers an angular range of 360°. Preferably, but not exclusively, the second fuel injection openings 17 are arranged at equal spacing on this circular contour 19. The second, relatively ignitable fuel can therefore be injected into the combustion chamber via the second fuel injection openings 17 within an angular range of 360°.

[0024] The pitch circle contour 18, on which the first fuel injection openings 16 are arranged, covers an angular range of 360°-δ. δ is between 15° and 65°, in particular between 20° and 60°, particularly preferably between 20° and 45°. δ accordingly defines a remaining pitch circle contour on which no first fuel injection openings 16 are arranged. On the pitch circle contour 18, the first fuel injection openings 16 are preferably, but not exclusively, arranged at equal spacing. The remaining pitch circle contour defined by δ, on which no first fuel injection openings 16 are arranged, faces the circular contour 19 on which the second fuel injection openings 17 are arranged.

[0025] Preferably, a ratio h / x between the height offset h of the circular contour 19, on which the second fuel injection openings 17 are arranged, and the partial circle contour 18, on which the first fuel injection openings 16 are arranged, and the distance x between the center point 20 of the partial circle contour 18 and the center point 21 of the circular contour 19 is between 0.1 and 0.4, in particular between 0.15 and 0.35, preferably between 0.17 and 0.29.

[0026] As already explained, the height offset h is the distance between the plane of the circular contour 19, on which the second fuel injection openings 17 are arranged, and the plane of the partial circle contour 18, on which the first fuel injection openings 16 are arranged. The distance x corresponds to the distance between the center point 20 of the partial circle contour 18 and the center point 21 of the circular contour 19.

[0027] As already explained, the first fuel injection openings 16 are configured to inject the first, relatively unignitable fuel into the combustion chamber of the cylinder, specifically with a first spray cone characterized by the cone angle β. This cone angle β corresponds to the angle between the outer surface of the spray cone and a longitudinal center axis thereof. The second fuel injection openings 17 are configured to inject the second, relatively ignitable fuel into the combustion chamber in a second spray cone with a second cone angle α, wherein the second cone angle α is in turn the angle between the outer surface of the second spray cone and its longitudinal center axis.

[0028] The first cone angle β is smaller than the second cone angle α. In particular, the first cone angle β is between 66° and 88°, in particular between 68° and 86°, particularly preferably between 70° and 84°. The second cone angle α is between 70° and 92°, in particular between 72° and 90°, particularly preferably between 74° and 88°.

[0029] The invention allows for the optimal introduction of fuel into the combustion chamber of a cylinder in different operating modes of an internal combustion engine, preferably designed as a dual-fuel internal combustion engine. Thus, in a first operating mode, both a first, relatively unignitable fuel and, for igniting the same, a second, relatively ignitable fuel can be optimally introduced into the combustion chamber of a cylinder and thus combusted. In a second operating mode, the second, relatively ignitable fuel can be optimally introduced into the combustion chamber of a cylinder and thus combusted. List of reference symbols

[0030] 10Fuel injector 11Main body 12First needle guide 13Second needle guide 14First nozzle needle 15Second nozzle needle 16First fuel injection opening 17Second fuel injection opening 18Partial circle contour 19Circular contour 20Center point 21Center point

Claims

1. A fuel injector (10) of an internal combustion engine, which is designed to supply fuel to a combustion chamber of a cylinder of the internal combustion engine, comprising a first nozzle needle (14) which is movably guided in a first needle guide (12) and which interacts with first fuel injection openings (16) in such a way that the first nozzle needle (14), depending on its position, either allows or blocks a fuel flow of a first, relatively unignitable fuel through the first fuel injection openings (16), comprising a second nozzle needle (15) which is movably guided in a second needle guide (13) and which interacts with second fuel injection openings (17) in such a way that the second nozzle needle (15), depending on its position, either allows or blocks a fuel flow of a second, relatively ignitable fuel, which serves to ignite the first fuel, through the second fuel injection openings (17),wherein the first fuel injection openings (16) are arranged along a partial circle contour (18) and the second fuel injection openings (17) are arranged along a circular contour (19) such that a distance (x) between the center point (20) of the partial circle contour (18) and the center point (21) of the circular contour (19) is greater than the sum of the radius (r1) of the partial circle contour (18) and the radius (r2) of the circular contour (19), wherein in the installed state of the fuel injector, the second fuel injection openings (17) protrude deeper or further into a combustion chamber of the cylinder than the first fuel injection openings (16).

2. Fuel injector (10) according to claim 1, wherein the circular contour (19) on which the second fuel injection openings (17) are arranged covers an angular range of 360°.

3. Fuel injector (10) according to claim 1 or 2, the partial circle contour (18) on which the first fuel injection openings (16) are arranged covers an angular range of 360°-δ, wherein δ is between 15° and 60°, in particular between 20° and 60°, preferably between 20° and 45°, wherein the remaining partial circle contour defined by δ, on which no first fuel injection openings (16) are arranged, faces the circular contour (19) on which the second fuel injection openings (17) are arranged.

4. Fuel injector (10) according to claim 1, 2 or 3, wherein a ratio between a height offset (h) of the circular contour (19) on which the second fuel injection openings (17) are arranged and the partial circle contour (18) on which the first fuel injection openings (16) are arranged and the distance (x) between the center point (20) of the partial circle contour (18) and the center point (21) of the circular contour (19) is between 0.1 and 0.4, in particular between 0.15 and 0.35, preferably between 0.17 and 0.

29.

5. Fuel injector (10) according to one of claims 1 to 4, wherein the first fuel injection openings (16) are configured to inject the first fuel into the combustion chamber in a first spray cone with a first cone angle (β), wherein the second fuel injection openings (17) are configured to inject the second fuel into the combustion chamber in a second spray cone with a second cone angle (α), wherein the first cone angle (β) is smaller than the second cone angle (α).

6. Fuel injector (10) according to one of claims 1 to 5, the first cone angle (β) is between 66° and 88°, in particular between 68° and 86°, preferably between 70° and 84°. The second cone angle (α) is between 70° and 92°, in particular between 72° and 90°, preferably between 74° and 88°.

7. Internal combustion engine, having cylinders which are arranged to ignite a first fuel with the aid of a second fuel for combustion thereof in the cylinders, each cylinder having a fuel injector (10) according to one of claims 1 to 6.

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