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, comprising a first nozzle needle (14) guided in a first needle guide (12) which interacts with first fuel injection openings (16) in such a way that, depending on its position, it opens or closes a flow of a first, non-ignitable fuel through the first fuel injection openings, and comprising a second nozzle needle (15) guided in a second needle guide (13) which interacts with second and third fuel injection openings (17a, 17b) in such a way that, depending on its position, it opens or closes a flow of a second, ignitable fuel through the second and third fuel injection openings, or opens or closes a flow through the second fuel injection openings and closes or closes a flow through the third fuel injection openings, or opens or closes a flow through the second and third fuel injection openings,wherein the first fuel injection openings (16) are configured to inject the first fuel in a first spray cone with a first cone angle (β), wherein the second fuel injection openings (17a) are configured to inject the second fuel in a second spray cone with a second cone angle (α1), wherein the third fuel injection openings (17b) are configured to inject the second fuel in a third spray cone with a third cone angle (α2).

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 has two nozzle needles that are movably guided in corresponding needle guides. First fuel injection openings interacting with a first nozzle needle and second fuel injection openings interacting with a second nozzle needle are each arranged along a circular contour. There are significant limitations when injecting the fuel into the combustion chamber of a cylinder, so that the combustion chamber cannot be used optimally.

[0006] Based on this, the present invention is based on the object of creating a novel fuel injector 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 10.

[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.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 and with third fuel injection openings in such a way that the second nozzle needle, depending on its position, either blocks a fuel flow of a second, relatively ignitable fuel through both the second fuel injection openings and the third fuel injection openings or releases it through the second fuel injection openings and blocks it through the third fuel injection openings or releases it through both the second fuel injection openings and the third fuel injection openings.

[0008] 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. 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. The third fuel injection openings are configured to inject the second fuel into the combustion chamber in a third spray cone with a third cone angle.

[0009] With the fuel injector according to the invention, both the first, relatively unignitable fuel and the second, relatively readily ignitable fuel can be optimally introduced into the combustion chamber of a cylinder. If, for example, in a first operating mode, the first, relatively unignitable fuel is to be combusted with ignition by means of the second, relatively readily ignitable fuel, the first, relatively unignitable fuel can be injected into the combustion chamber of the cylinder via the first fuel injection openings, and to ignite the first, relatively readily ignitable fuel, the second, relatively readily ignitable fuel can be injected into the combustion chamber of the cylinder via the second fuel injection openings. In this first operating mode, the third fuel injection openings are preferably permanently closed.In the second operating mode, in which only the second, relatively flammable fuel is to be burned, the first fuel injection ports are permanently closed, and the second fuel is then injected into the combustion chamber of the respective cylinder via the second fuel injection ports and the third fuel injection ports. The combustion chamber of a combustion chamber can thus be optimally utilized in both operating modes.

[0010] Preferably, the second cone angle is smaller than the third cone angle. If the second cone angle is smaller than the third cone angle, the second, relatively ignitable fuel used to ignite the first, relatively unignitable fuel can be injected particularly advantageously into the combustion chamber of a cylinder in the first operating mode.

[0011] The first cone angle is preferably smaller than the second cone angle. Alternatively, the first cone angle is larger than the second cone angle and smaller than the third cone angle, or alternatively, even larger than the third cone angle.

[0012] Preferably, the first fuel injection openings are arranged along a partial circular contour, the second fuel injection openings along a first circular contour and the third fuel injection openings along a second circular contour, wherein the center point of the partial circular contour is arranged on a longitudinal central axis of the first needle guide, wherein the first circular contour and the second circular contour are arranged concentrically to one another in the projection along a longitudinal central axis of the second needle guide, such that the center point of the first circular contour and the center point of the second circular contour are both arranged on the longitudinal central axis of the second needle guide,wherein a distance between the longitudinal center axis of the first needle guide and the longitudinal center axis of the second needle guide is greater than the sum of the radius of the pitch circle contour and the radius of the first circle contour and greater than the sum of the radius of the pitch circle contour and the radius of the second circle contour. This arrangement of the first, second, and third fuel injection openings is particularly preferred for optimal use of the combustion chamber of a cylinder.

[0013] When the fuel injector is installed, the second and / or third fuel injection openings preferably extend deeper or further into a combustion chamber of the cylinder than the first fuel injection openings. This allows the second fuel to be introduced into the combustion chamber of the respective cylinder particularly advantageously, particularly in the second operating mode, in which only the second, relatively ignitable fuel is to be burned.

[0014] Preferably, the second fuel injection openings and the third fuel injection openings are at least partially offset from one another in the circumferential direction. This also serves to optimally introduce fuel into the combustion chamber of a cylinder, particularly in the second operating mode, in which only the second, relatively ignitable fuel is introduced into the combustion chamber of the respective cylinder, namely via the second and third fuel injection openings.

[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 first schematic, partial cross-section through the fuel injector according to the invention of Fig. 1; Fig. 3 a second schematic, partial cross-section through the fuel injector according to the invention of Fig. 1, Fig. 4 an alternative to Fig. 3.

[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. In a first operating mode, it introduces a first, relatively unignitable fuel and a second, relatively ignitable fuel in order to ignite the first, relatively unignitable fuel via the second, relatively ignitable fuel in the first operating mode. Furthermore, in a second operating mode, in which exclusively the second, relatively ignitable fuel is combusted, the fuel injector is intended 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 that provides two needle guides 12, 13. 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.

[0018] First fuel injection openings 16 interact with the first nozzle needle 14 in such a way that the first nozzle needle 14, depending on its position in the first needle guide 12, either releases or blocks a fuel flow of a first, relatively unignitable fuel through the first fuel injection openings 16.

[0019] Second fuel injection openings 17a and third fuel injection openings 17b interact with the second nozzle needle 15.

[0020] In a first relative position thereof in the second needle guide 13, the second nozzle needle 15 blocks the fuel flow of the second, relatively ignitable fuel through both the second fuel injection openings 17a and the third fuel injection openings 17b.

[0021] In a second relative position of the second nozzle needle 15 in the second needle guide 13, the second nozzle needle releases the fuel flow of the second, relatively ignitable fuel through the second fuel injection openings 17a, but blocks the fuel flow through the third fuel injection openings 17b.

[0022] In a third relative position of the second nozzle needle 15 in the second needle guide 13, the same releases the fuel flow of the second, relatively ignitable fuel through both the second fuel injection openings 17a and the third fuel injection openings 17b.

[0023] The first fuel injection openings 16, which serve to introduce the first, relatively unignitable fuel into the combustion chamber of a cylinder, are configured to inject the first fuel into the combustion chamber of a respective cylinder in a first spray cone with a first cone angle β. The second fuel injection openings 17a are configured to inject the second, relatively ignitable fuel into the combustion chamber of the respective cylinder in a second spray cone with a second cone angle α1. The third fuel injection openings 17b are configured to inject the second, relatively ignitable fuel into the combustion chamber of the respective cylinder in a third spray cone with a third cone angle α2. These cone angles α1, α2 and β are, according to the Fig. 1 to 4 each by an angle which a lateral surface of the respective spray cone encloses with a longitudinal central axis of the respective spray cone.

[0024] It is therefore within the scope of the invention to use the second nozzle needle 15, which interacts with both the second fuel injection openings 17a and the third fuel injection openings 17b, to introduce the second, relatively ignitable fuel. If an internal combustion engine with such a fuel injector is operated in the first operating mode, in which a first, relatively unignitable fuel is to be combusted and ignited via the second, relatively ignitable fuel, the first, relatively unignitable fuel is introduced into the combustion chamber of the respective cylinder via the first fuel injection openings 16, and the second, relatively ignitable fuel is preferably introduced exclusively via the second fuel injection openings 17a. In the first operating mode, the third fuel injection openings 17b are then not used.If, however, such an internal combustion engine is to be operated in a second operating mode in which only the second, relatively ignitable fuel is burned, the first fuel injection openings 16 are permanently closed and the second, relatively ignitable fuel is introduced into the combustion chamber of the respective cylinder via both the second fuel injection openings 17a and the third fuel injection openings 17b.

[0025] The second cone angle α1 is preferably smaller than the third cone angle α2. The second cone angle α1, with which the second fuel injection openings 17a inject the second, relatively ignitable fuel into the combustion chamber of a respective cylinder, is therefore smaller than the third cone angle α2 of the third spray cone, via which the third fuel injection openings 17b inject the second, relatively ignitable fuel into the combustion chamber of the respective cylinder. The third cone angle α2 is between 66° and 88°, preferably between 68° and 86°. The second cone angle α1 is smaller than the third cone angle α2. Preferably, the second cone angle α1 is smaller than 68°, more preferably smaller than 66°.

[0026] The first cone angle β is preferably smaller than the second cone angle α1. Alternatively, the first cone angle β is larger than the second cone angle α1 and smaller than the third cone angle α2. Alternatively, the first cone angle β is larger than the third cone angle α2.

[0027] The first fuel injection openings 16, which serve to inject the first, relatively unignitable fuel, are preferably arranged along a pitch circle contour. This pitch circle contour, on which the first fuel injection openings 16 are arranged, extends over an angular range of 360°-δ, where δ defines a remaining pitch circle contour on which no first fuel injection openings 16 are arranged. The center point of this pitch circle contour is arranged on a longitudinal center axis of the first needle guide 12, which coincides with a longitudinal center axis of the first nozzle needle 14 and the longitudinal center axis of the first spray cone of the first fuel injection openings 16.

[0028] The second fuel injection openings 17a and the third fuel injection openings 17b are both arranged along a circular contour, specifically the second fuel injection openings 17a along a first circular contour and the third fuel injection openings 17b along a second circular contour. The center point of the first circular contour and the center point of the second circular contour are both arranged on a longitudinal center axis of the second needle guide 13, which coincides with a longitudinal center axis of the second nozzle needle 15 and with the longitudinal center axis of the second spray cone of the second fuel injection openings 17a and the longitudinal center axis of the third spray cone of the third fuel injection openings 17b.

[0029] The first circular contour and the second circular contour are therefore arranged concentrically to one another in the projection along the longitudinal center axis of the second needle guide 13 and thus in the projection along the longitudinal center axis of the second nozzle needle 15. This means that the center point of the first circular contour, on which the second fuel injection openings 17a are arranged, and the center point of the second circular contour, on which the third fuel injection openings 17b are arranged, are both arranged on the longitudinal center axis of the second needle guide 13 and thus on the longitudinal center axis of the second nozzle needle 15, but are offset from one another in the direction of the longitudinal center axis of the second needle guide 13 and thus in the direction of the longitudinal center axis of the second nozzle needle 15.

[0030] A distance x between the longitudinal center axis of the first needle guide 12 and the longitudinal center axis of the second needle guide 13 is greater than the sum of the radius r3 of the pitch circle contour and the radius r1 of the first circle contour and further greater than the sum of the radius r3 of the pitch circle contour and the radius r2 of the second pitch circle contour.

[0031] Neither the first circular contour on which the second fuel injection openings 17a are arranged, nor the second circular contour on which the third fuel injection openings 17b are arranged, which are arranged concentrically to one another in the projection along the longitudinal center axis of the second needle guide 13 and thus in the projection along the longitudinal center axis of the second nozzle needle 15, therefore intersect the partial circle contour on which the first fuel injection openings 16 are positioned.

[0032] The remaining pitch circle contour defined by the angle δ, on which no first fuel injection openings 16 are arranged, faces the first circular contour and the second circular contour.

[0033] The second fuel injection openings 17a are the fuel injection openings for the second, relatively ignitable fuel that open before the third fuel injection openings 17b in the second operating mode, in which only the second, relatively ignitable fuel is combusted. The second fuel injection openings 17a preferably have a smaller cross-sectional opening than the third fuel injection openings 17b.

[0034] When the fuel injector is installed, the second and / or third fuel injection openings 17a, 17b are arranged deeper or further into a combustion chamber of the cylinder or protrude deeper or further into the combustion chamber of the respective cylinder than the first fuel injection openings 16. Preferably, both the second and third fuel injection openings 17a and 17b protrude deeper or further into the combustion chamber than the first fuel injection openings 16.

[0035] Fig. 3 and Fig. 4 differ in the relative position of the second fuel injection openings 17a and the third fuel injection openings 17b with respect to the penetration depth of the same into the combustion chamber of the respective cylinder. Fig. 3 the second fuel injection openings 17a are arranged deeper in the combustion chamber than the third fuel injection openings 17b. In Fig. 4, however, the third fuel injection openings 17b are arranged deeper or further into the combustion chamber than the second fuel injection openings 17a. While in Fig. 3 of the nozzle needle 15 is both flowed around by the second fuel and flowed through by the second fuel, is in Fig. 4 the nozzle needle 15 is exclusively flowed around by the second fuel.

[0036] As already explained above, the third fuel injection openings 17b have a larger flow cross-section than the second fuel injection openings 17a. The number of third fuel injection openings 17b can also be greater than the number of second fuel injection openings 17a. However, the number of second fuel injection openings 17a can also correspond to the number of third fuel injection openings 17b. Preferably, at least some of the, particularly preferably all, second and third fuel injection openings are offset from one another in the circumferential direction, specifically on concentric circular paths as seen in the projection along the longitudinal center axis of the second needle guide 13 and thus in the projection along the longitudinal center axis of the second nozzle needle 15.

[0037] The invention allows a combustion chamber of a cylinder of an internal combustion engine to be optimally filled with fuel, both when a first, relatively unignitable fuel is to be combusted by ignition with the aid of a second, relatively ignitable fuel, and when only the second, relatively ignitable fuel is to be combusted. This can increase efficiency and reduce NOx emissions. List of reference symbols 10 Fuel injector 11 Basic body 12 first needle guide 13 second needle guide 14 first nozzle needle 15 second nozzle needle 16 first fuel injection port 17a second fuel injection opening 17b third fuel injection port QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2013 000 048 B3

[0005]

Claims

[1] 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, with a first nozzle needle (14) movably guided in a first needle guide (12) which interacts with first fuel injection openings (16) in such a way that the first nozzle needle (14) either releases or blocks a fuel flow of a first, relatively unignitable fuel through the first fuel injection openings (16), depending on its position, with a second nozzle needle (15) movably guided in a second needle guide (13) which interacts with second fuel injection openings (17a) and with third fuel injection openings (17b) in such a way that the second nozzle needle (15), depending on its position, either blocks a fuel flow of a second, relatively ignitable fuel through both the second fuel injection openings (17a) and the third fuel injection openings (17b) or releases it through the second fuel injection openings (17a) and blocks it through the third fuel injection openings (17b) or releases it through both the second fuel injection openings (17a) and the third fuel injection openings (17b), wherein the first fuel injection openings (16) are arranged 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 (17a) are arranged to inject the second fuel into the combustion chamber in a second spray cone with a second cone angle (α1), wherein the third fuel injection openings (17b) are arranged to inject the second fuel into the combustion chamber in a third spray cone with a third cone angle (α2). [2] Fuel injector (10) according to claim 1, wherein the second cone angle (α1) is smaller than the third cone angle (α2). [3] Fuel injector (10) according to claim 1 or 2, wherein the first cone angle (β) is smaller than the second cone angle (α1). [4] Fuel injector (10) according to claim 1 or 2, wherein the first cone angle (β) is greater than the second cone angle (α1) and smaller than the third cone angle (α2). [5] Fuel injector (10) according to claim 1, 2 or 3, wherein the first fuel injection openings (16) are arranged along a partial circle contour, the center of which is arranged on a longitudinal center axis of the first needle guide (12), wherein the second fuel injection openings (17a) are arranged along a first circular contour, wherein the third fuel injection openings (17b) are arranged along a second circular contour, wherein the first circular contour and the second circular contour are arranged concentrically to one another in the projection along a longitudinal central axis of the second needle guide (13), such that the center of the first circular contour and the center of the second circular contour are both arranged on the longitudinal central axis of the second needle guide (13), wherein a distance (x) between the longitudinal center axis of the first needle guide (12) and the longitudinal center axis of the second needle guide (13) is greater than the sum of the radius (r3) of the partial circle contour and the radius (r1) of the first circle contour and is greater than the sum of the radius (r3) of the partial circle contour and the radius (r2) of the second circle contour. [6] Fuel injector (10) according to claim 5, wherein in the installed state of the fuel injector, the second and / or third fuel injection openings (17a, 17b) protrude deeper or further into a combustion chamber of the cylinder than the first fuel injection openings (16). [7] Fuel injector (10) according to claim 5 or 6, wherein the second fuel injection openings (17a) and the third fuel injection openings (17b) are at least partially offset from one another in the circumferential direction. [8] Fuel injector (10) according to claim 5, 6, or 7, wherein the first and second circular contours on which the second and third fuel injection openings (17a, 17b) are arranged each cover an angular range of 360°. [9] Fuel injector (10) according to claim 5, 6, 7 or 8, wherein the partial circle contour on which the first fuel injection openings (16) are arranged covers an angular range of 360°-δ, wherein the remaining partial circle contour defined by δ, on which no first fuel injection openings (16) are arranged, faces the first and second circular contour. [10] Internal combustion engine, with cylinders which are arranged to ignite a first fuel with the aid of a second fuel for combustion thereof in the cylinders, wherein each cylinder has a fuel injector (10) according to any one of claims 1 to 9.

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