Fuel injector of internal combustion engine and internal combustion engine

Abstract

To provide an internal combustion engine having a new type of fuel injector that has high operational stability and is easy to manufacture.SOLUTION: A fuel injector 10 of an internal combustion engine is for supplying fuel to a combustion chamber of the internal combustion engine. The fuel injector 10 comprises: a first nozzle needle 14 that is guided movably in a first nozzle guide 12 and operates to open or block a first fuel passing through a first fuel injection opening 16; a second nozzle needle 15 that is guided movably in a second needle guide 13 and operates to open or block a second fuel passing through a second fuel injection opening 17; at least one first fuel storage space 22 formed in the fuel injector 10 for the first fuel; and at least one second fuel storage space 23 for the second fuel. The first fuel storage space 22 and the second fuel storage space 23 are arranged next to one another in the transverse direction or the radial direction of the fuel injector 10 and overlap in the longitudinal direction or the axial direction of the fuel injector 10.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. [Background technology]

[0002] The present invention particularly relates to the field of so-called large engines or large internal combustion engines, whose cylinders have a piston diameter of at least 140 mm, in particular at least 175 mm. Such large internal combustion engines are, for example, marine engines. Dual-fuel internal combustion engines are already known as marine engines. Known dual-fuel internal combustion engines can operate in a first operating mode in which the dual-fuel internal combustion engine burns a first fuel, in particular a relatively easy-to-ignite fuel, and in a second operating mode in which the dual-fuel internal combustion engine burns a second fuel, in particular a relatively difficult-to-ignite fuel. The first relatively easy-to-ignite fuel can be, for example, diesel fuel. The second relatively difficult-to-ignite fuel can be, for example, methanol, ethanol, or ammonia. In the second operating mode, the second relatively difficult-to-ignite fuel, in particular methanol, ethanol, or ammonia, can be ignited via the first relatively easy-to-ignite fuel, in particular diesel fuel.

[0003] The patent document 1 discloses a fuel injector that can be used to introduce both a first, relatively easy-to-ignite fuel and a second, relatively difficult-to-ignite fuel into the combustion chamber of a cylinder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] German Patent No. 102013000048 Summary of the Invention [Problem to be solved by the invention]

[0005] Starting from this, the present invention is based on the object of creating a new type of fuel injector for an internal combustion engine, which has high operational stability and is simple to manufacture, and an internal combustion engine having such a fuel injector. This object is achieved through a fuel injector according to claim 1 and an internal combustion engine according to claim 11. [Means for solving the problem]

[0006] The fuel injector comprises a first nozzle needle movably guided in a first needle guide, which interacts with the first fuel injection opening in such a way that the first nozzle needle opens or blocks a fuel flow of a first fuel through the first fuel injection opening depending on the position of the first nozzle needle, and a second nozzle needle movably guided in a second needle guide, which interacts with the second fuel injection opening in such a way that the second nozzle needle opens or blocks a fuel flow of a second fuel through the second fuel injection opening depending on the position of the second nozzle needle. At least one first fuel storage space for a first fuel and at least one second fuel storage space for a second fuel are incorporated into the fuel injector, and the at least one first fuel storage space and the at least one second fuel storage space are arranged next to each other in the lateral or radial direction of the fuel injector and overlap each other in the longitudinal or axial direction of the fuel injector.

[0007] In the fuel injector according to the present invention, the at least one first fuel storage chamber and the at least one second fuel storage chamber are arranged adjacent to each other in the transverse or radial direction of the fuel injector and thus overlapping and parallel to each other in the longitudinal or axial direction of the fuel injector, which ensures high operational stability of the fuel injector on the one hand and easy manufacturing adaptability of the fuel injector on the other hand. Stresses in the region of the fuel storage chambers can be reduced even under high operating pressures. Autofrettage can be used to achieve the desired internal pressure resistance of the fuel storage chambers, thereby further reducing manufacturing costs.

[0008] Preferentially, the diameter of the at least one first fuel storage space is smaller than the diameter of the at least one second fuel storage space, and the ratio between the diameter of the second fuel storage space and the diameter of the at least one first fuel storage space is 1.05 to 1.25. This is advantageous because the operating pressure of the first fuel is typically higher than the operating pressure of the second fuel. Therefore, the diameter of the at least one first fuel storage space is smaller than the diameter of the at least one second fuel storage space. This can ensure high operational stability.

[0009] Preferentially, the ratio between the distance between a first fuel storage space and an adjacent second fuel storage space of a fuel injector according to the invention and the distance between two adjacent second fuel storage spaces of a fuel injector according to the invention is between 0.75 and 1.25, preferentially between 0.75 and 0.95, which also helps to achieve a high operational stability of the fuel injector according to the invention.

[0010] Preferentially, at least two first fuel storage spaces having different lengths are incorporated into the fuel injector according to the invention, the length ratio between the shorter or shortest first fuel storage space length and the longer or longest first fuel storage space length being 0.5 to 0.95, preferentially 0.5 to 0.75. Alternatively or additionally, at least two second fuel storage spaces having different lengths are incorporated into the fuel injector, the length ratio between the shorter or shortest second fuel storage space length and the longer or longest second fuel storage space length being 0.5 to 0.95, preferentially 0.5 to 0.75.

[0011] By opening and closing the nozzle needles through different lengths of the fuel storage spaces for the first fuel and / or the second fuel in the fuel injector according to the present invention, vibrations of different wavelengths are excited in the respective fuel circuits, which at least partially overlap and cancel each other out, which also helps to improve the operational stability of the fuel injector according to the present invention.

[0012] Preferred further developments of the invention emerge from the dependent claims and the following description.Exemplary embodiments of the invention are explained in more detail by means of the drawings, without being limited thereto. [Brief explanation of the drawings]

[0013] [Figure 1] 2 is a longitudinal or axial cross-section through a first fuel injector according to the present invention; FIG. [Figure 2] 2 is a detailed view of the fuel injector of FIG. 1 according to the present invention. [Figure 3] FIG. 2 is a further detailed view of the fuel injector of FIG. 1. [Figure 4] FIG. 4 is a detailed view of a second fuel injector according to the present invention. [Figure 5] FIG. 5 is a further detailed view of the fuel injector of FIG. 4. [Figure 6] FIG. 10 is a detailed view of the third fuel injector. [Figure 7] FIG. 10 is a detailed view of a fourth fuel injector. [Figure 8] 4 is a timing chart for the fuel injector of FIGS. 1, 2 and 3. FIG. [Figure 9] 6 is a timing chart for the fuel injector of FIGS. 4 and 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention relates to a fuel injector for an internal combustion engine. Such a fuel injector is designed to supply fuel to the combustion chamber of a cylinder of an internal combustion engine.

[0015] The fuel injector according to the invention is useful for supplying different fuels to an internal combustion engine, in particular designed as a dual-fuel internal combustion engine, i.e. a first, relatively easy-to-ignite fuel in a first operating mode and a second, relatively hard-to-ignite fuel in a second operating mode, and for igniting the first, relatively easy-to-ignite fuel in order to ignite the second, relatively hard-to-ignite fuel via the first, relatively easy-to-ignite fuel.

[0016] The first, relatively easy-to-ignite fuel is specifically diesel fuel, and the second, relatively hard-to-ignite fuel may be methanol, ethanol, or ammonia.

[0017] 1 shows a cross-section through a first fuel injector 10 according to the invention, which comprises a nozzle needle receiver 11 which provides a first needle guide 12 for a first nozzle needle 14 and a second needle guide 13 for a second nozzle needle 15. Furthermore, the nozzle needle receiver 11 provides a first fuel injection opening 16 and a second fuel injection opening 17. Depending on the position of the nozzle needles 14, 15, the nozzle needles 14, 15 open or block the fuel flow through the fuel injection openings 16, 17.

[0018] The fuel injector 10 according to the present invention further comprises a fuel storage space receiver 18 and, in the exemplary embodiment shown, a solenoid valve receiver 19 disposed between the fuel storage space receiver 18 and the nozzle needle receiver 11.

[0019] A first solenoid valve 20 disposed in the solenoid valve receiver 19 serves to control the first nozzle needle 14 to either open or block fuel flow through the first fuel injection opening 16 by changing the position of the first nozzle needle 14.

[0020] A second solenoid valve 21 arranged in the solenoid valve receiving body 19 serves to control the second nozzle needle 15 in order to change the position of the second nozzle needle 15 and, depending thereon, to either open or block the second fuel flow through the second fuel injection opening 17.

[0021] As already explained, the fuel injector 10 comprises a fuel storage space receiver 18. Incorporated within the fuel injector 10, i.e., within the fuel storage space receiver 18 of the fuel injector 10, are at least one first fuel storage space 22 for a first fuel and at least one second fuel storage space 23 for a second fuel.

[0022] At least one first fuel storage space 22 is connected to a high-pressure circuit for a first fuel via a high-pressure connector 24 of the fuel injector 10, while at least one second fuel storage space 23 is connected to a high-pressure circuit for a second fuel via a further high-pressure connector 25.

[0023] At least one first fuel storage space 22 of the fuel injector 10 according to the present invention is connected to the nozzle needle receiving body 11 via a first fuel line 26 and to at least one second fuel storage space 26 of the fuel injector 10 according to the present invention via a second fuel line 27, these fuel lines 26, 27 extending from the fuel storage space receiving body 18 through the solenoid valve receiving body 19 and, preferentially, through a plate-shaped intermediate body 28 arranged between the solenoid valve receiving body 19 and the nozzle needle receiving body 11 in the direction of the nozzle needle receiving body 11.

[0024] 1 further shows the sleeve body 29, with the solenoid valve receiving body 19 and the intermediate body 28 partially and completely disposed within the sleeve body 29 and the nozzle needle receiving body 11 and the fuel storage space receiving body 18. By means of the sleeve body 29, the fuel injector 10 can be mounted, for example, in a corresponding recess in the cylinder head of a cylinder of an internal combustion engine.

[0025] According to the present invention, the at least one first fuel storage space 22 for the first fuel and the at least one second fuel storage space 23 for the second fuel are arranged next to each other in the transverse or radial direction R of the fuel injector 10, and the at least one first fuel storage space 22 for the first fuel and the at least one second fuel storage space 23 for the second fuel overlap each other in the longitudinal or axial direction A of the fuel injector 10 and also extend parallel to each other in the longitudinal or axial direction A of the fuel injector 10.

[0026] 1, 2, and 3, a single first fuel storage space 22 and a single second fuel storage space 23 are incorporated into the fuel injector 10, i.e., its fuel storage space receiver 18. Here, the diameter D1 of the first fuel storage space 22 is smaller than the diameter D2 of the second fuel storage space 23. Furthermore, the length L1 of the first fuel storage space 22 is longer than the length L2 of the second fuel storage space 23, the difference in length between the two fuel storage spaces 22, 23 being indicated by ΔL in FIG.

[0027] The fuel injector 10 can be easily manufactured while achieving high operational stability in that the fuel storage spaces 22, 23 are arranged adjacent to each other in the lateral or radial direction R. Because the fuel storage spaces 22, 23 arranged adjacent to each other in the lateral or radial direction R have relatively small diameters D1 and D2, the area over which the high pressure existing in each fuel storage space 22, 23 acts is reduced, resulting in reduced stress.

[0028] Furthermore, the small diameter fuel storage spaces 22, 23 can function to the desired internal pressure resistance by autofrettage, and as a result, there is no need to employ gas nitriding to achieve the internal pressure resistance. Therefore, the fuel injector 10 according to the present invention is easier to manufacture overall.

[0029] In addition to the high pressure connectors 24, 25, Figure 1 also shows low pressure connectors 30, 31 of the fuel injector 10, namely a low pressure connector 30 for a fuel circuit of a first fuel and a low pressure connector 31 for a fuel circuit of a second fuel.

[0030] 2 and 3 show details of the fuel injector 10 of FIG. 1 according to the present invention in the region of the fuel storage space receiver 18. A single first fuel storage space 22 and a single second fuel storage space 23 are incorporated into the fuel injector 10, i.e., the fuel storage space receiver 18. The single first fuel storage space 22 and the single second fuel storage space 23 have different diameters D1 and D2 according to FIG. 2. According to FIG. 2, the diameter D1 of the first fuel storage space 22 for the first fuel is smaller than the second diameter D2 of the second fuel storage space 23 for the second fuel. The second fuel storage space 23 for the second fuel has a length L2 in the axial direction A, which is shorter than the length L1 of the first fuel storage space 22 for the first fuel.

[0031] The diameter D1 of the first fuel storage space 22 for the first fuel can match the diameter D2 of the second fuel storage space 23 for the second fuel, but it is preferred that the diameter D2 of the second fuel storage space 23 for the second fuel is larger than the diameter D1 of the first fuel storage space 22 for the first fuel.

[0032] In particular, it is provided that the ratio D2-D1 between the diameter D1 of the second fuel storage space 23 for the second fuel and the diameter D1 of the first fuel storage space 22 for the first fuel is between 1.05 and 1.25.

[0033] 2 shows a distance X12 between the two fuel storage spaces 22, 23. This distance X12 corresponds to the wall thickness of the fuel storage space receiver 18 between the fuel storage spaces 22, 23 arranged next to each other in the lateral or radial direction R.

[0034] Figures 4 and 5 again show details of the fuel injector 10 according to the invention in the region of the fuel storage space receiver 18. In Figures 4 and 5, two first fuel storage spaces 22 for a first fuel and two second fuel storage spaces 23 for a second fuel are incorporated into the fuel injector 10, the geometry of which together creates four fuel storage spaces 22, 23, as can be seen from Figure 4. Figure 5 helps to explain the different lengths of the fuel storage spaces 22, 23.

[0035] According to FIG. 5, the fuel storage spaces 22, 23 viewed in the transverse or radial direction R are again arranged next to each other, with the two first fuel storage spaces 22 for the first fuel having the same diameter D1, which is smaller than the identical diameter D2 of the two second fuel storage spaces 23 for the second fuel.

[0036] The fuel storage spaces 22, 23 are arranged relative to one another in such a way that two adjacent second fuel storage spaces 23 for the second fuel have a distance X22, which corresponds to the distance between a second fuel storage space 23 for the second fuel and an adjacent first fuel storage space 22 for the first fuel.

[0037] According to FIG. 4, the distance X22 between two adjacent second fuel storage spaces 23 for the second fuel is greater than the distance X12 between the first fuel storage space 22 for the first fuel and the adjacent second fuel storage space 23 for the second fuel, and the ratio X12:X22 between the distance X12 and the distance X22 is 0.75 to 0.95.

[0038] In contrast to the exemplary embodiment shown, it is also possible for the ratio X12:X22 between the distance X12 and the distance X22 to be between 1.05 and 1.25. It is also possible for the distance X12 to match the distance X22, with the ratio X12:X22 being 1.0.

[0039] As shown in Figure 5, the two first fuel storage spaces 22 for the first fuel have different lengths, with the longer or longest of the two first fuel holes 22 having a length L1L and the shorter or shortest of the two first fuel storage spaces 22 having a length L1K. Similarly, the two second fuel storage spaces 23 in Figure 5 have different lengths, with the shorter or shortest of the two second fuel storage spaces 23 having a length L2K and the longer or longest of the two second fuel storage spaces 23 having a length L2L. The difference in length is noted by ΔL1 and ΔL2, respectively.

[0040] In particular, it is provided that the length ratios L1K:L1L and / or the length ratios L2K:L2L each amount to 0.5 to 0.95, preferentially 0.5 to 0.75. When opening and closing the fuel injection openings 16 and 17, respectively, via the respective nozzle needles 14 and 15 through these different lengths of the first fuel storage space 22 and / or the different lengths of the second fuel storage space 23, pressure oscillations with different wavelengths in the respective high-pressure circuits of the respective fuels can be generated, which pressure oscillations overlap and at least partially cancel each other out.

[0041] Thus, Figure 8 shows a time curve of a pressure oscillation 32 forming in one of the two high-pressure fuel circuits for the fuel injector 10 of Figures 2 and 3, with the period Δt indicating the time at which the pressure oscillation 32 occurs as a result of reduced nozzle needle closing. Figure 9 shows three time curves of pressure oscillations 33, 34, and 35 over time t, i.e., for the fuel injector 10 of Figures 4 and 5, with pressure oscillations 33 and 34 superimposed on pressure oscillation 35. Pressure oscillations 32 and 34 partially cancel each other, so that the resulting pressure oscillation 35 of Figure 9 decays significantly more rapidly than pressure oscillation 32 of Figure 8. In this way, the period between two successive injection events can be reduced.

[0042] In the exemplary embodiment of Figures 1 to 5, the number of first fuel storage spaces 22 matches the number of second fuel storage spaces 23. In contrast, Figures 6 and 7 show an exemplary embodiment of a fuel injector 10 according to the present invention, in which the number of first fuel storage spaces 22 is less than the number of second fuel storage spaces 23. Thus, two second fuel storage spaces 23 for the second fuel and a single first fuel storage space 22 for the first fuel are incorporated into the fuel injector 10 in Figure 6. In Figure 7, four second fuel storage spaces 23 for the second fuel and a single first fuel storage space 22 for the first fuel are incorporated into the fuel injector 10. Figures 6 and 7 then show the diameters D1 and D2 of the first fuel storage spaces 22 and second fuel storage spaces 23, as well as the distances X12 and X22 therebetween.

[0043] In the exemplary embodiment of Figures 6 and 7, the second fuel storage spaces 23 may then also have different lengths in order to achieve overlapping and at least partial cancellation of pressure waves in the high-pressure system of the second fuel.

[0044] As shown in particular in Figures 5 and 6, when a single first fuel storage space 22 for a first fuel is incorporated into the fuel injector 10, the first fuel storage space 22 can be arranged on the longitudinal axis of the fuel injector 10 according to Figure 6, and the second fuel storage spaces 23 for the second fuel are arranged around the first fuel storage space 22 for the first fuel in a point-symmetrical manner with respect to the longitudinal axis of the fuel injector 10. In Figure 5, the first fuel storage space 22 for the first fuel extends off-center, i.e., distributed with respect to the longitudinal axis of the fuel injector 10. In Figure 4, the first fuel storage space 22 for the first fuel and the second fuel storage spaces 23 for the second fuel are incorporated off-center, i.e., distributed with respect to the longitudinal axis of the fuel injector 10, but are therein in a point-symmetrical manner with respect to the longitudinal axis of the fuel injector 10.

[0045] The first fuel is a relatively easy-to-ignite fuel, specifically diesel fuel, and the second fuel is a relatively hard-to-ignite fuel, specifically methanol, ethanol, or ammonia. In particular, in one operating mode, the second, relatively hard-to-ignite fuel, specifically methanol, ethanol, or ammonia, is to be burned, and the second fuel can be ignited via the first fuel. [Explanation of symbols]

[0046] 10 fuel injector 11 Nozzle needle receiver 12 First needle guide 13 Second needle guide 14 First nozzle needle 15 Second nozzle needle 16 First fuel nozzle 17 Second fuel nozzle 18 Fuel storage space receiver 19 Solenoid valve receiver 20 First solenoid valve 21 Second solenoid valve 22 First fuel storage space 23 Second fuel storage space 24 First high voltage connector 25 Second high voltage connector 26 First fuel line 27 Second fuel line 28 Intermediates 29 Sleeve body 30 First low voltage connector 31 Second low voltage connector 32 Pressure oscillations 33 Pressure oscillations 34 Pressure oscillations 35 Pressure oscillations

Claims

1. A fuel injector (10) for an internal combustion engine, designed to supply fuel to a combustion chamber of a cylinder of said engine, comprising: a first nozzle needle (14) movably guided in a first needle guide (12), which interacts with the first fuel injection opening (16) in such a way that, depending on the position of the first nozzle needle (14), the first nozzle needle (14) opens or blocks a fuel flow of a first fuel through the first fuel injection opening (16); a second nozzle needle (15) movably guided in a second needle guide (13) and interacting with the second fuel injection opening (17) in such a way that, depending on the position of the second nozzle needle (15), the second nozzle needle (15) opens or blocks a fuel flow of a second fuel through the second fuel injection opening (17); at least one fuel storage space (22) for said first fuel incorporated in said fuel injector (10); at least one second fuel storage space (23) for said second fuel integrated in said fuel injector (10); Equipped with The at least one first fuel storage space (22) and the at least one second fuel storage space (23) are arranged adjacent to each other in a lateral or radial direction of the fuel injector (10) and overlap each other in a longitudinal or axial direction of the fuel injector (10).

2. The fuel injector (10) of claim 1, wherein the number of the first fuel storage spaces (22) matches the number of the second fuel storage spaces (23).

3. The fuel injector (10) of claim 1, wherein the number of first fuel storage spaces (22) is less than the number of second fuel storage spaces (23).

4. 2. The fuel injector (10) of claim 1, wherein a diameter (D1) of the at least one first fuel storage space (22) is smaller than a diameter (D2) of the at least one second fuel storage space (23) or matches the diameter (D2) of the at least one second fuel storage space (23).

5. 5. The fuel injector (10) of claim 4, wherein the diameter (D1) of the at least one first fuel storage space (22) is smaller than the diameter (D2) of the at least one second fuel storage space (23), and a ratio D2:D1 between the diameter (D2) of each of the second fuel storage spaces (23) and the diameter (D1) of each of the first fuel storage spaces (22) is between 1.05 and 1.

25.

6. 2. The fuel injector (10) according to claim 1, wherein a ratio X12:X22 between a distance (X12) between a first fuel storage space (22) and an adjacent second fuel storage space (23) and a distance (X22) between two adjacent second fuel storage spaces (23) is between 0.75 and 1.

25.

7. The fuel injector (10) of claim 6, wherein the ratio X12:X22 is between 0.75 and 0.

95.

8. 2. The fuel injector (10) of claim 1, wherein at least two first fuel storage spaces (22) having different lengths are incorporated into the fuel injector (10), and a length ratio L1K:L1L between the length L1K of the shorter or shortest first fuel storage space (22) and the length L1L of the longer or longest first fuel storage space (22) is between 0.5 and 0.

95.

9. 2. The fuel injector (10) of claim 1, wherein at least two second fuel storage spaces (23) having different lengths are incorporated into the fuel injector (10), and the length ratio L2K:L2L between the length L2K of the shorter or shortest second fuel storage space (23) and the length L2L of the longer or longest second fuel storage space (23) is 0.5 to 0.

95.

10. a first solenoid valve (20) for controlling the first nozzle needle (14) and a second solenoid valve (21) for controlling the second nozzle needle (15); 2. The fuel injector (10) of claim 1, wherein the first solenoid valve (20) and the second solenoid valve (21) are arranged between the fuel storage space (22, 23) and the nozzle needle (14, 15) in the longitudinal direction or the axial direction of the fuel injector (10).

11. An internal combustion engine having cylinders, each cylinder being provided with a fuel injector (10) according to any one of claims 1 to 10.

Images