Fuel injector of internal combustion engine, and internal combustion engine

Abstract

To provide a new type fuel injector of an internal combustion engine, and the internal combustion engine with the injector.SOLUTION: A fuel injector (10) of an internal combustion engine comprises: a first nozzle needle (14) interacted with a first fuel injection orifice (16) to open or block a flow of first fuel with comparatively low ignitability passing through the first fuel injection orifice (16); and a second nozzle needle (15) to block a flow of second fuel with comparatively high ignitability passing through both of a second fuel injection orifice (17a) and a third fuel injection orifice (17b), or open the flow of the second fuel passing through the second fuel injection orifice (17a) and block the flow of the second fuel passing through the third fuel injection orifice (17b), or open the flow of the second fuel passing through both of the second fuel injection orifice (17a) and the third fuel injection orifice (17b).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fuel injector for an internal combustion engine. Furthermore, the present invention relates to an internal combustion engine having 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, the cylinders of which have a piston diameter of at least 140 mm, in particular at least 175 mm. Such large internal combustion engines are, for example, ship engines.

Background Art

[0003] Dual-fuel internal combustion engines are already known as ship engines. The actually known dual-fuel internal combustion engines can operate in a first operating mode in which a first fuel, in particular a less ignitable fuel, is combusted, and a second operating mode in which a second fuel, in particular a relatively ignitable fuel, is combusted.

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

[0005] Patent Document 1 discloses a fuel injector that can introduce both a first fuel with relatively low ignitability and a second fuel with relatively high ignitability into the combustion chamber of a cylinder in a first operating mode of a dual-fuel internal combustion engine. The fuel injector disclosed therein has two nozzle needles that are movably guided within corresponding needle guides. A first fuel injection orifice that interacts with the first nozzle needle and a second fuel injection orifice that interacts with the second nozzle needle are each arranged along a circular contour. When injecting fuel into the combustion chamber of the cylinder, there are significant restrictions, and the combustion space of the combustion chamber cannot be optimally utilized.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention has been made in view of such circumstances, and its object is to provide a new type of fuel injector and an internal combustion engine equipped with the same.

Means for Solving the Problems

[0008] This problem is solved by the fuel injector according to claim 1 and the internal combustion engine according to claim 10.

[0009] The fuel injector comprises a first nozzle needle movably guided within a first needle guide, and the first nozzle needle interacts with a first fuel injection orifice so as to open or block a flow of a first relatively low ignitability fuel through the first fuel injection orifice according to its position. Further, the fuel injector comprises a second nozzle needle movably guided within a second needle guide, and the second needle guide interacts with a second fuel injection orifice and a third fuel injection orifice so as to block a flow of a second relatively high ignitability fuel through both the second fuel injection orifice and the third fuel injection orifice, or to open a flow of a second fuel through the second fuel injection orifice and block a flow of the second fuel through the third fuel injection orifice, or to open a flow of the second fuel through both the second fuel injection orifice and the third fuel injection orifice, according to its position.

[0010] The first fuel injection orifice is provided for injecting a first fuel within a first spray cone into a combustion space at a first cone angle. The second fuel injection orifice is provided for injecting a second fuel within a second spray cone into the combustion space at a second cone angle. The third fuel injection orifice is provided for injecting the second fuel within a third spray cone into the combustion space at a third cone angle.

[0011] According to the fuel injector of the present invention, both the first fuel with relatively low ignitability and the second fuel with relatively high ignitability can be optimally introduced into the combustion space in the cylinder. For example, in the first operating mode, when the first fuel with relatively low ignitability that is ignited with the assistance of the second fuel with relatively high ignitability is combusted, the first fuel with relatively low ignitability can be injected through the first fuel injection orifice, and in order to ignite this, the second fuel with relatively high ignitability can be injected into the combustion chamber of the cylinder through the second fuel injection orifice. In this first operating mode, the third fuel injection orifice is preferentially and permanently closed. In the second operating mode, only the second fuel with relatively high ignitability is combusted, the first fuel injection orifice is permanently closed, and the second fuel is introduced into the combustion space of each cylinder through the second fuel injection orifice and the third fuel injection orifice. Therefore, the combustion space of the combustion chamber can be optimally utilized in both operating modes.

[0012] Preferably, the second conical angle is smaller than the third conical angle. In particular, when the second conical angle is smaller than the third conical angle, the second fuel with relatively high ignitability that is used in the first operating mode to ignite the first fuel with relatively low ignitability can be injected into the combustion space of the cylinder particularly advantageously.

[0013] The first conical angle is preferably smaller than the second conical angle. Alternatively, the first conical angle is larger than the second conical angle and smaller than the third conical angle, or larger than the third conical angle.

[0014] Preferably, the first fuel injection orifice is arranged along a pitch circle contour, the second fuel injection orifice is arranged along a first circular contour, the third fuel injection orifice is arranged along a second circular contour, the first circular contour and the second circular contour are arranged concentrically with each other, and the distance between the center point of the pitch circle contour and the center points of the first and second circular contours is greater than the sum of the radius of the pitch circle contour and the radius of the first circular contour and greater than the sum of the radius of the pitch circle contour and the radius of the second circular contour. This arrangement of the first, second, and third fuel injection orifices is particularly preferred for optimally utilizing the combustion space of the combustion chamber of the cylinder.

[0015] Preferably, the second and / or third fuel injection orifices protrude deeper or further into the combustion chamber of the cylinder than the first fuel injection orifice in the installed state of the fuel injector. Therefore, the second fuel can be introduced particularly advantageously into the combustion chamber of each cylinder, especially in the second operating mode in which only the second fuel with relatively high ignitability is combusted.

[0016] Preferably, the second fuel injection orifice and the third fuel injection orifice are at least partially offset from each other when viewed in the circumferential direction. This also helps to optimally introduce fuel into the combustion chamber of the cylinder, especially in the second operating mode, in which only the second fuel with relatively high ignitability, i.e., through the second and third fuel injection orifices, is introduced into the combustion chamber of each cylinder.

[0017] Preferred further developments of the invention result from the dependent claims and the following description. Hereinafter, embodiments of the invention will be described in detail with reference to the drawings, but the invention is not limited thereto.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention relates to a fuel injector for an internal combustion engine. Such a fuel injector supplies fuel to the combustion chamber of a cylinder of an internal combustion engine. The fuel injector according to the present invention functions to supply different fuels to an internal combustion engine designed as a dual-fuel internal combustion engine, for example, in a first operating mode, a first fuel with relatively low ignitability and a second fuel with relatively high ignitability are introduced, and the first fuel with relatively low ignitability is ignited in the first operating mode through the second fuel with relatively high ignitability. Also, in a second operating mode in which only the second fuel with relatively high ignitability is burned, the same fuel is injected into the combustion chamber of the cylinder through the fuel injector. The first fuel with relatively low ignitability can be methanol, ethanol or ammonia. The second fuel with relatively high ignitability is particularly diesel fuel.

[0020] FIGS. 1 to 3 show different views of a fuel injector 10 according to the present invention. The fuel injector 10 has a body 11 with two needle guides 12, 13. A first nozzle needle 14 is movably guided in the first needle guide 12, and a second nozzle needle 15 is movably guided in the second needle guide 13.

[0021] The first fuel injection orifice 16 interacts with the first nozzle needle 14 such that the first nozzle needle 14 opens or blocks the flow of the first fuel with relatively low ignitability through the first fuel injection orifice 16 according to its position within the first needle guide 12.

[0022] The second fuel injection orifice 17a and the third fuel injection orifice 17b interact with the second nozzle needle 15.

[0023] At the first relative position of the second nozzle needle 15, in the second needle guide 13, the flow of the second relatively easily ignitable fuel passing through both the second fuel injection orifice 17a and the third fuel injection orifice 17b is blocked.

[0024] At the second relative position of the second nozzle needle 15 in the second needle guide 13, the flow of the second relatively easily ignitable fuel passing through the second fuel injection orifice 17a is opened, but the flow of fuel passing through the third fuel injection orifice 17b is blocked.

[0025] At the third relative position of the second nozzle needle 15 in the second needle guide 13, the flow of the second relatively easily ignitable fuel passing through both the second fuel injection orifice 17a and the third fuel injection orifice 17b is opened.

[0026] The first fuel injection orifice 16 is for introducing the first fuel with relatively low ignitability into the combustion chamber of the cylinder, and is provided for injecting the first fuel in the first spray cone into the combustion space of each cylinder at the first cone angle β. The second fuel injection orifice 17a is for injecting the second fuel with relatively high ignitability in the second spray cone into the combustion space of each cylinder at the second cone angle α1. The third fuel injection orifice 17b is for injecting the second fuel with relatively high ignitability in the third spray cone into the combustion space of each cylinder at the third cone angle α2. These cone angles α1, α2, and β shown in FIGS. 1 to 4 are the angles formed by the side surface of each spray cone and the longitudinal central axis of each spray cone.

[0027] Accordingly, according to the present invention, in order to introduce a second fuel with relatively high ignitability, a second nozzle needle 15 that interacts with both the second fuel injection orifice 17a and the third fuel injection orifice 17b is utilized. When an internal combustion engine having such a fuel injector is operated in a first operation mode in which a first fuel that is relatively difficult to ignite is combusted and ignited via a second fuel that is relatively easy to ignite, the first fuel that is relatively difficult to ignite is introduced into the combustion space of each cylinder via the first fuel injection orifice 16, and the second fuel that is relatively easy to ignite is preferentially and exclusively introduced via the second fuel injection orifice 17a. At this time, in the first operation mode, the third fuel injection orifice 17b is not utilized. On the other hand, when the internal combustion engine is operated in a second operation mode in which only the second fuel with relatively high ignitability is combusted, the first fuel injection orifice 16 is permanently closed, and the second fuel with relatively high ignitability is introduced into the combustion chamber of each cylinder via the second fuel injection orifice 17a and the third fuel injection orifice 17b.

[0028] The second conical angle α1 is preferably smaller than the third conical angle α2. Accordingly, the second conical angle α1 at which the second fuel injection orifice 17a injects the second fuel with relatively high ignitability into the combustion chamber of each cylinder is smaller than the third conical angle α2 of the third spray cone at which the third fuel injection orifice 17b injects the second fuel with relatively high ignitability into the combustion chamber of each cylinder. The third conical angle α2 is between 66° and 88°, preferably between 68° and 86°. The second conical angle α1 is smaller than the third conical angle α2. Preferably, the second conical angle α1 is smaller than 68°, preferably smaller than 66°.

[0029] The first conical angle β is preferably smaller than the second conical angle α1. Alternatively, the first conical angle β is larger than the second conical angle α1 and smaller than the third conical angle α2. Alternatively, the first conical angle β is larger than the third conical angle α2.

[0030] The first fuel injection orifice 16 is for injecting a first fuel with relatively low ignitability and is preferentially arranged along the pitch circle contour. The pitch circle contour where the first fuel injection orifice 16 is arranged extends over an angular range of 360° to δ, where δ defines the residual pitch circle contour where the first fuel injection orifice 16 is not arranged.

[0031] Both the second fuel injection orifice 17a and the third fuel injection orifice 17b are arranged along circular contours. That is, the second fuel injection orifice 17a is arranged along a first circular contour, and the third fuel injection orifice 17b is arranged along a second circular contour. The first circular contour and the second circular contour are arranged concentrically with each other.

[0032] The distance x between the center point of the pitch circle contour where the first fuel injection orifice 16 is arranged and the center points of the first and second circular contours where the second fuel injection orifice 17a and the third fuel injection orifice 17b are respectively arranged is greater than the sum of the radius r3 of the pitch circle contour and the radius r1 of the first circular contour, and is further greater than the sum of the radius r3 of the pitch circle contour and the radius r2 of the second pitch circle contour.

[0033] Since the first circular contour and the second circular contour are arranged concentrically with each other, they do not bisect the pitch circle contour where the first fuel injection orifice 16 is located.

[0034] The residual pitch circle contour defined by the angle δ where the first fuel injection orifice 16 is not arranged faces the first circular contour and the second circular contour.

[0035] The second fuel injection orifice 17a is a fuel injection orifice for a second relatively high ignitability fuel that opens earlier than the third fuel injection orifice 17b in a second operation mode in which only the second relatively high ignitability fuel is combusted. The second fuel injection orifice 17a preferably has a smaller cross-sectional opening than the third fuel injection orifice 17b.

[0036] The second and / or third fuel injection orifices 17a, 17b are disposed deeper in the combustion chamber of the cylinder or protrude deeper into the combustion chamber of the cylinder than the first fuel injection orifice 16 when the fuel injector is installed. The second and third fuel injection orifices 17a, 17b are deeper or protrude further into the combustion chamber than the first fuel injection orifice 16.

[0037] FIGS. 3 and 4 show that the relative positions of the second fuel injection orifice 17a and the third fuel injection orifice 17b are different based on the depth of penetration into the combustion chambers of the respective cylinders. Accordingly, the second fuel injection orifice 17a in FIG. 3 is disposed at a deeper position in the combustion chamber than the third fuel injection orifice 17b. In contrast, in FIG. 4, the third fuel injection orifice 17b is disposed at a deeper position in the combustion chamber than the second fuel injection orifice 17a. In FIG. 3, the nozzle needle 15 is flowed by and also penetrated by the second fuel, whereas the nozzle needle 15 in FIG. 4 is only flowed by the second fuel.

[0038] As already explained, the third fuel injection orifice 17b has a larger cross-sectional area than the second fuel injection orifice 17a. The number of the third fuel injection orifices 17b may be larger than the number of the second fuel injection orifices 17a. However, the number of the second fuel injection orifices 17a can also correspond to the number of the third fuel injection orifices 17b. Preferably, at least some, particularly preferably all, of the second and third fuel injection orifices are offset from each other in the circumferential direction, i.e., are disposed on concentric paths.

[0039] According to the present invention, the combustion chamber of the cylinder of an internal combustion engine can be optimally filled with fuel not only when a first fuel with relatively low ignitability is to be combusted by ignition with the assistance of a second fuel with relatively high ignitability, but also especially when only the second fuel with relatively high ignitability is to be combusted. Thereby, the efficiency can be improved. Also, the NOx emission can be reduced.

Explanation of Signs

[0040] 10 Fuel injector 11 Main body 12 First needle guide 13 Second needle guide 14 First nozzle needle 15 Second nozzle needle 16 First fuel injection orifice 17a Second fuel injection orifice 17b Third fuel injection orifice

Claims

1. 1. A fuel injector (10) for an internal combustion engine for supplying fuel to a combustion chamber of a cylinder of the internal combustion engine, comprising: a first nozzle needle (14) movably guided in a first needle guide (12) and interacting with a first fuel injection orifice (16) in such a way that, depending on its position, the first nozzle needle (14) opens or blocks the flow of a first, relatively low-ignition fuel through the first fuel injection orifice (16); a second nozzle needle (15) movably guided in a second needle guide (13), which interacts with the second and third fuel injection orifices in such a way that, depending on its position, the second nozzle needle (15) either blocks the flow of the second relatively ignitable fuel through both the second and third fuel injection orifices (17a) and (17b), or opens the flow of the second fuel through the second fuel injection orifice (17a) and blocks the flow of the second fuel through the third fuel injection orifice (17b), or opens the flow of the second fuel through both the second and third fuel injection orifices (17a) and (17b); Equipped with said first fuel injection orifice (16) for injecting said first fuel in a first spray cone at a first cone angle (β) into said combustion space; said second fuel injection orifice (17a) is for injecting a second fuel in a second spray cone with a second cone angle (α1) into said combustion space; said third fuel injection orifice (17b) is for injecting a second fuel in a third spray cone at a third cone angle (α2) into said combustion space; Fuel injectors.

2. The fuel injector of claim 1 , wherein the second cone angle (α1) is smaller than the third cone angle (α2).

3. 3. The fuel injector according to claim 1 or 2, wherein the first cone angle (β) is smaller than the second cone angle (α1).

4. 3. The fuel injector according to claim 1 or 2, wherein the first cone angle (β) is greater than the second cone angle (α1) and less than the third cone angle (α2).

5. The first fuel injection orifices (16) are arranged along a pitch circle contour; the second fuel injection orifices (17a) are arranged along a first circular contour; the third fuel injection orifices (17b) are arranged along a second circular contour; the first circular contour and the second circular contour are arranged concentrically with each other; 4. The fuel injector according to claim 1, 2 or 3, wherein a distance (x) between a center point of the pitch circle contour and a center point of the first and second circular contours is greater than a sum of a radius (r3) of the pitch circle contour and a radius (r1) of the first circular contour, and is greater than a sum of a radius (r3) of the pitch circle contour and a radius (r2) of the second circular contour.

6. 6. A fuel injector as claimed in claim 5, wherein the second and / or third fuel injection orifices (17a, 17b) in an installed state of the fuel injector protrude deeper or further into the combustion chamber of a cylinder than the first fuel injection orifice (16).

7. 7. The fuel injector according to claim 5 or 6, wherein the second fuel injection orifice (17a) and the third fuel injection orifice (17b) are at least partially offset relative to each other in a circumferential view.

8. 8. A fuel injector as claimed in claim 5, 6 or 7, wherein the first and second circular contours on which the second and third fuel injection orifices (17a, 17b) are arranged respectively cover an angular range of 360°.

9. 9. A fuel injector according to claim 5, 6, 7 or 8, wherein the pitch circle contour in which the first fuel injection orifices (16) are located covers an angular range of 360° to δ, and the remaining pitch circle contour defined by δ in which the first fuel injection orifices (16) are not located faces the first and second circular contours.

10. a cylinder equipped to ignite a first fuel with the assistance of a second fuel, the cylinder being for combusting the first fuel therein; An internal combustion engine, wherein each cylinder is equipped with a fuel injector (10) according to any one of the preceding claims.

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