Fuel injection valve

Abstract

Described is a fuel injection valve (10.1) comprising: a housing having a control fluid inlet, a fuel inlet and a nozzle body with an injection valve seat; a high pressure control chamber (32) arranged in the housing and connected to the control fluid inlet; a fuel chamber (22) arranged in the housing and extending from the fuel inlet to the injection valve seat; a control piston (51) which is arranged in the housing and which can be adjusted along a longitudinal axis (L) and which is acted upon by a control pressure spring with a closing force towards the injection valve seat; the hydraulic control device is used for controlling the control piston to adjust along the longitudinal axis; a nozzle needle arranged at an end of the control piston facing the injection valve seat, the nozzle needle being designed to interact with the injection valve seat to inject fuel into a combustion chamber of the internal combustion engine, the nozzle needle being movable by adjusting the control piston along the longitudinal axis.

Description

Technical Field

[0001] The present invention relates to a fuel injection valve for intermittently injecting fuel into the combustion chamber of an internal combustion engine. Background Technology

[0002] Fuel injection valves are used to inject fuel into the combustion chamber of internal combustion engines, especially diesel engines. In recent years, in addition to traditional diesel, various gaseous or liquid fuels, such as hydrogen, methane, methanol, and ammonia, have been proposed, especially as green and low-pollution alternatives.

[0003] Because of the wide variety of fuels that can be used, it may be advantageous to adapt the fuel injection valve to possible variations. One option is to provide a multi-fuel injection valve that can be used for a variety of fuels. Such an option is a dual-fuel system that can use, for example, liquid fuels (such as diesel or marine diesel) or gaseous fuels (such as hydrogen, methane, or biogas).

[0004] WO2015 / 101406A1 describes such a dual-fuel fuel injection system having a first axially travelable nozzle needle for dispensing liquid fuel via a first nozzle assembly of a dual-fuel fuel injector. The first nozzle needle is preferably housed within the nozzle body of the fuel injector. The dual-fuel fuel injector also includes a plurality of axially travelable second nozzle needles (e.g., two, three, four, five, or more) arranged around the first nozzle needle for dispensing gaseous fuel via the second nozzle assembly of the dual-fuel fuel injector. Specifically, an apparatus is provided having a central first nozzle needle and second nozzle needles arranged eccentrically relative to it, preferably concentrically with the first nozzle needle. Similar to the first nozzle needle, the second nozzle needles are also preferably housed within the nozzle body. Within the second nozzle assembly, each of the second nozzle needles is, for example, provided with one or more gas injection nozzle openings on the injector, which can be released via the second nozzle needle. Summary of the Invention

[0005] Known multi-fuel injection systems, such as the dual-fuel injection system described at the beginning (which uses multiple nozzle needles), result in correspondingly higher space requirements and complexity. The increased space requirements are also due to the presence of multiple independent loops for the first and second nozzle needles, even if only a specific fuel is needed in a particular application. Furthermore, these systems are relatively immutable because the number and structure of the nozzle needles and nozzle body are fixed and cannot be changed. This can be particularly disadvantageous because the type of fuel required for a particular application is often unknown in advance. Their manufacture and maintenance are relatively expensive due to the complexity of the injector design, for example, according to WO2015 / 101406A1. Moreover, long-term operational reliability can be compromised by the complex design. Since internal combustion engines with such injection systems are used in fields such as mining, marine, or other heavy applications, injector failure leading to engine failure can quickly incur high costs. Therefore, the reliability and durability of the injectors are of particular importance.

[0006] In this regard, it is desirable to provide a fuel injection valve that has an advantageously simpler structure and provides reliable controllability of the injection process while having improved adaptability to different fuels.

[0007] Therefore, the object of the present invention is to provide a fuel injection valve that at least partially improves upon the prior art.

[0008] This objective is achieved by a fuel injection valve having the features of the independent claim. Advantageous embodiments of the invention are provided in the dependent claims, as well as in this specification and the accompanying drawings.

[0009] This invention relates to a fuel injection valve for intermittently injecting fuel into the combustion chamber of an internal combustion engine, comprising: a housing extending along a longitudinal axis having a control fluid inlet, a fuel inlet, and a nozzle body with an injection valve seat; a high-pressure control chamber disposed within the housing and connected to the control fluid inlet; a fuel chamber disposed within the housing and extending from the fuel inlet to the injection valve seat; a control piston disposed within the housing for adjustment along the longitudinal axis, the control piston being acted upon by a control pressure spring with a closing force toward the injection valve seat; a hydraulic control device for controlling the adjustment of the control piston along the longitudinal axis; and a nozzle needle disposed at the end of the control piston facing the injection valve seat, the nozzle needle being at least partially disposed within the nozzle body and designed to interact with the injection valve seat to inject fuel into the combustion chamber of the internal combustion engine, wherein the nozzle needle can be moved by adjusting the control piston along the longitudinal axis.

[0010] In known solutions, the position of the nozzle needle is controlled by adjusting the adjusting section of the nozzle needle. Compared to known solutions, providing a separate control piston and control fluid in the high-pressure control chamber allows for more precise control, especially since it can be designed independently of the characteristics of the fuel used. The nozzle needle, injection valve seat, and / or injection opening can also be adapted to the requirements of the fuel in the fuel chamber.

[0011] Therefore, in this fuel injection valve, the control components and the injection components can be structurally decoupled from each other, at least in their main parts. This improves the fuel injection valve's adaptability to the requirements of the control system or fuel, both for the control components (e.g., the control piston and / or the control fluid in the high-pressure control chamber) and for the injection components (e.g., the nozzle needle, the injection valve seat, at least one injection opening, and / or the fuel chamber).

[0012] For example, due to the separation of the control and injection components, the fuel injection valve can be operated with gaseous fuel and liquid control fluid for hydraulic control. However, the fuel injection valve can also be used with liquid fuel by replacing the injection components.

[0013] The separate design of the control piston and nozzle needle offers a further advantage: individual, independent guides can be provided for each. Because the control piston and nozzle needle are designed as separate components, slight misalignment of the control piston and nozzle needle during injector assembly has only a minor or negligible effect. The control piston and nozzle needle can each be guided by their respective guides, and slight misalignment will not cause harmful friction in the respective guides. This ensures perfect and low-friction operation.

[0014] Preferably, the end face of the control piston facing the injection valve seat interacts with the end face of the nozzle needle facing away from the injection valve seat to move the nozzle needle. In one variation, the end face of the control piston facing the injection valve seat is larger than the end face of the nozzle needle facing away from the injection valve seat. In an alternative variation, the end face of the control piston facing the injection valve seat is smaller than the end face of the nozzle needle facing away from the injection valve seat. In another alternative variation, the end face of the control piston facing the injection valve seat is the same size as the end face of the nozzle needle facing away from the injection valve seat.

[0015] Preferably, the high-pressure control chamber and the fuel chamber are fluid-separated.

[0016] Fluid separation between the high-pressure control chamber and the fuel chamber allows for a separate loop for the control fluid and fuel. This improves the decoupling of the control components and the injection components. In this context, those skilled in the art will understand that fluid separation can be achieved in a manner that minimizes leakage from the high-pressure control chamber to the fuel chamber (within acceptable limits).

[0017] In one embodiment, the fuel injection valve has an intermediate body in which a control piston and a high-pressure control chamber are at least partially arranged, and a nozzle body is adjacent to the downstream end face of the intermediate body.

[0018] The intermediate body can accommodate the control piston, allowing its end facing the injection valve seat to interact with the nozzle needle.

[0019] In one embodiment, the intermediate body has a transverse wall that defines a high-pressure control chamber axially relative to the nozzle body. The transverse wall of the intermediate body can provide spatial separation between the high-pressure control chamber and the fuel chamber.

[0020] In one embodiment, the nozzle body or intermediate body has a guide hole in which an adjusting section of the control piston arranged at its end facing the injection valve seat and / or an adjusting section of the nozzle needle arranged at its end opposite to the injection valve seat are guided in a sliding fit.

[0021] The sliding fit in the guide hole allows for fluid separation between the high-pressure control chamber and the fuel chamber. Furthermore, the guide hole can provide a seat or passage for adjusting sections of the control piston and / or nozzle needle, allowing them to meet or interact. In one variation, for example, the adjusting section of the control piston can be guided in the guide hole such that the control piston protrudes through the guide hole into the nozzle body and meets the nozzle needle there. In another variation, the adjusting section of the nozzle needle can be guided in the guide hole such that the nozzle needle protrudes through the guide hole into the intermediate body and meets the control piston there. In yet another variation, both the adjusting section of the control piston and the adjusting section of the nozzle needle can protrude into the guide hole such that the control piston and the nozzle needle meet directly or indirectly (e.g., through the adjusting chamber) in the guide hole.

[0022] In one embodiment, the guide hole has a circumferential annular space, and the fuel injection valve has a leakage outlet and a leakage discharge passage extending from the annular space to the leakage outlet.

[0023] Control fluid leaking from the pilot hole can be collected in the annular space and discharged to the leak outlet through the leak discharge channel. This minimizes or reduces control fluid leakage from the high-pressure control chamber to the fuel chamber through the pilot hole.

[0024] In one embodiment, the leakage discharge passage has a check valve designed to open at an opening pressure between the control fluid inlet pressure and the fuel chamber pressure, wherein the opening pressure is preferably closer to the fuel chamber pressure than the control fluid inlet pressure.

[0025] In one embodiment, the opening pressure is less than 10% or about 10% higher than the fuel chamber pressure.

[0026] Preferably, the leak discharge channel primarily or solely discharges control fluid. Preferably, the leak discharge channel does not discharge any fuel.

[0027] Therefore, a check valve set to the appropriate opening pressure can be used to activate the leak discharge channel when leakage needs to be discharged. Using the leak discharge channel and check valve, sealing oil can be advantageously eliminated.

[0028] In an internal combustion engine with multiple cylinders, a check valve can be individually arranged in / on each fuel injection valve. In a variant, a common check valve can be arranged in / on a combined leak discharge channel that collects leaked emissions from multiple fuel injection valves.

[0029] The check valve can be located inside or outside the housing of the fuel injection valve.

[0030] Check valves can be designed as mechanically spring-loaded valves with a specific, set, or adjustable opening pressure. Alternatively, check valves can be designed as solenoid-controlled valves with an electrically or electronically adjustable opening pressure. The electrically or electronically adjustable opening pressure can be flexibly set to the optimal opening pressure required based on the operating conditions of the internal combustion engine. For example, if the control fluid inlet pressure is variable, the opening pressure can be changed according to the load and engine speed to better control the fuel injection of the internal combustion engine.

[0031] Preferably, a jet pressure spring is arranged in the nozzle body, which presses the nozzle needle against the control piston.

[0032] The injection pressure spring ensures that the nozzle needle follows the movement of the control piston, especially when the control piston moves away from the injection valve seat to open the fuel injection valve. Preferably, the injection pressure spring is designed such that the end face of the nozzle needle contacts the end face of the control piston due to the injection pressure spring. The injection pressure spring can be particularly advantageous in the case of gaseous fuel and liquid control fluid, because in this case the pressure in the fuel chamber is typically significantly lower than the pressure in the high-pressure control chamber.

[0033] In one embodiment, a fluid-closed regulating chamber is arranged between the control piston and the nozzle needle, the regulating chamber being radially defined by the nozzle body or intermediate body and axially defined by the control piston and the nozzle needle.

[0034] In this context, those skilled in the art will understand that, except for minor (within acceptable limits) leaks, the regulating chamber should be fluid-closed.

[0035] The regulating chamber can be particularly advantageous in the case of liquid fuel, because in this case the pressure in the fuel chamber is usually high enough, and the nozzle needle can be regulated by controlling the axial movement of the piston and via the regulating chamber.

[0036] In one embodiment, the fuel injection valve has an actuator housing, to which the nozzle body is preferably releasably fastened by a cap nut, such that the nozzle body and the nozzle needle are replaceable.

[0037] The interchangeability of the nozzle body and nozzle needle offers the advantage that the fuel injection valve can be easily adapted to different fuels. The control components can remain unchanged because these components, particularly the control circuit, are decoupled from the injection components and fuel circuit, which simplifies adaptability. Therefore, depending on the fuel, fuel-adapted injection components can be used, such as nozzle bodies with adapted injection seats and / or injection openings and / or nozzle needles.

[0038] Therefore, fuel injection valves can be easily adapted to different applications.

[0039] In one embodiment, both the intermediate body and the nozzle body are releasably fastened to the actuator housing using a cap nut. The cap nut allows the nozzle body to be pressed onto the intermediate body and the intermediate body to be pressed onto the actuator housing in a known manner.

[0040] In one embodiment, the nozzle body is releasably fastened to the intermediate body using a cap nut.

[0041] In one embodiment, the nozzle needle is guided in the needle guide section of the nozzle body, wherein the nozzle needle preferably has at least one recess that extends longitudinally and opens radially outward.

[0042] Due to the separate design of the nozzle needle and control piston, it is not necessary to align the needle guide section with the control piston, as the needle guide section is associated with the nozzle needle. Fuel can flow longitudinally through the nozzle needle within the nozzle body to reach at least one injection opening due to at least one radially outward-opening recess.

[0043] In one embodiment, the nozzle body has concentric injection openings.

[0044] Concentric injection openings can provide a sufficiently large flow cross-section, which is particularly advantageous for gaseous fuels.

[0045] In one embodiment, the nozzle body has a plurality of spray openings arranged eccentrically.

[0046] Multiple injection openings arranged eccentrically are particularly advantageous for liquid fuels, in order to provide spatially uniform injection into the combustion chamber of an internal combustion engine.

[0047] In one embodiment, a cap is disposed at the downstream end of the nozzle body, the cap extending to cover at least one injection opening and having a concentric or at least one eccentric opening.

[0048] The cap provides the advantage that fuel exiting from the nozzle body through at least one injection opening can flow directly into the combustion chamber of the internal combustion engine in the direction of either a concentric or at least an eccentric opening, depending on the cap.

[0049] In one embodiment, the fuel chamber has a fuel supply section with a diameter larger than that of the control fluid supply section of the high-pressure control chamber.

[0050] Especially for gaseous fuels, a sufficiently large flow cross-section can be provided through the fuel supply section.

[0051] In one embodiment, the hydraulic control device is designed to move a control piston along a longitudinal axis by changing the pressure in the control chamber, wherein the hydraulic control device has an intermediate valve having an intermediate valve member that opens a first connection between a control fluid inlet connected to the high-pressure control chamber and the control chamber in a controlled open position, and interrupts the first connection between the control fluid inlet and the control chamber in a controlled closed position, and separates the control chamber from the valve chamber except for a throttling passage, wherein the fuel injection valve includes an electromagnetically actuated actuator device for connecting the valve chamber to a low-pressure control fluid return and separating the valve chamber from the low-pressure control fluid return.

[0052] By connecting the valve chamber to the low-pressure control fluid return, the intermediate valve member can be moved to the control closed position, causing the control piston to move away from the injection valve seat and thus lift the nozzle needle from the injection valve seat. By disconnecting the valve chamber from the low-pressure control fluid return, the intermediate valve member can be moved to the control open position, causing the control piston to move toward the injection valve seat and thus press the nozzle needle onto the injection valve seat.

[0053] The valve chamber can be connected to and separated from the low-pressure control fluid return via a push rod, which is pressed by an actuator device onto the low-pressure control fluid outlet of the valve chamber to close the low-pressure control fluid outlet and lifted from the low-pressure control fluid outlet to open it.

[0054] A portion of the control chamber is preferably located between the intermediate valve member and the control piston, such that the intermediate valve member and / or the control piston can be moved by changing the pressure in the control chamber.

[0055] A portion of the valve chamber is preferably located on the side of the intermediate valve member facing away from the control chamber.

[0056] In one embodiment, the control piston has a guide section at one end facing away from the injection valve seat, the guide section being guided in a guide sleeve in a sliding fit, wherein the fuel injection valve has an intermediate component that, together with the guide sleeve and the control piston, defines a control chamber, wherein the intermediate valve member is mushroom-shaped and has a shaft and a head guided in a guide recess of the intermediate component, wherein the intermediate valve has an intermediate valve seat formed on the head-facing side of the intermediate component and engaging with the head.

[0057] The mushroom-shaped intermediate valve component enables stable control via an intermediate valve, for example, compared to a disc-shaped intermediate valve component. Furthermore, the mushroom-shaped intermediate valve component offers the advantage of precise control using a small amount of control fluid. Therefore, due to the decoupling and replaceability of injection components for different fuels (e.g., gaseous or liquid fuels), fuel injection valves offer the possibility of utilizing the hydraulic control advantages of intermediate valves with mushroom-shaped intermediate valve components.

[0058] Several alternative, desirable green and climate-neutral fuels typically have poor ignition characteristics and may require relatively high ignition energies for clean combustion in piston internal combustion engines. This is likely especially true if the combustion process, like most large engines, involves autoignition and simultaneous high compression, such as in diesel engines. Since high compression leads to higher engine efficiency, i.e., lower fuel consumption, this can result in significant operating cost savings for large engines that typically operate at high loads for thousands of hours per year.

[0059] To ignite the alternative fuel during auto-ignition, a small amount of diesel fuel is typically injected under high pressure. This can be optimally provided by a micro-ignition injector or by a jet injector that allows the engine to run on diesel fuel up to full load and provides only a small ignition jet to ignite the alternative fuel when the engine is under high load with the alternative fuel.

[0060] Therefore, the hydraulic control for the fuel injection valve disclosed herein can also be advantageously operated with diesel fuel. This allows for the advantageous omission of a third, separate control fuel.

[0061] The throttling channel is preferably formed on the intermediate valve member, particularly preferably on the head of the intermediate valve member. However, the throttling channel may also be formed on an intermediate component. In other variations, the throttling channel may be formed between the intermediate valve member and another component, for example through a gap between the intermediate valve member and the intermediate component. The throttling channel formed on the intermediate valve member may lead into a blind hole formed in the intermediate valve member and belonging to the valve chamber on the side opposite to the control chamber. Preferably, the throttling channel is formed in the intermediate valve member adjacent to the control chamber. The throttling channel and the blind hole are preferably formed centered relative to the longitudinal axis. This allows the throttling channel to be formed to the desired length, and the blind hole to form part of the valve chamber.

[0062] In one embodiment, the intermediate valve member releases the second connection between the control fluid inlet and the valve chamber in the controlled open position of the intermediate valve member, and interrupts the second connection between the control fluid inlet and the valve chamber in the controlled closed position of the intermediate valve member.

[0063] Because the intermediate valve member releases the second connection between the control fluid inlet and the valve chamber in the open position, the valve chamber can be filled with control fluid through the second connection, which enables a faster opening movement of the intermediate valve member. In particular, the second connection improves valve chamber filling compared to fuel injection valves where, for example, the valve chamber is filled only from the control chamber through a throttling channel. Advantageously, the valve chamber can therefore be filled through the second connection even with only a small opening movement of the intermediate valve member. With the throttling channel, it is advantageous that only a small initial opening movement of the intermediate valve member caused by the flow of control fluid from the control chamber into the valve chamber through the throttling channel is sufficient, as a large amount of control fluid can subsequently fill the valve chamber through the second connection. By interrupting the second connection between the control fluid inlet and the valve chamber in the closed position of the intermediate valve member, adverse fuel losses and wear caused by the release of control fluid from the high-pressure chamber into the valve chamber during the injection process can be reduced or minimized, while releasing the second connection allows for rapid filling of the valve chamber for the opening movement of the intermediate valve member. Attached Figure Description

[0064] Embodiments of the invention will be explained in more detail with reference to the following figures and accompanying description. Schematic illustration:

[0065] Figure 1 A longitudinal sectional view of an embodiment of the fuel injection valve;

[0066] Figure 2 for Figure 1 An enlarged view of a portion of the longitudinal section;

[0067] Figure 3 for Figure 1 Another longitudinal section of the fuel injection valve, wherein the cross-sectional plane is relative to Figure 1 It rotated 90°;

[0068] Figure 4 for Figure 3 An enlarged view of a portion of the longitudinal section;

[0069] Figure 5 for Figure 4 A further enlarged view of the central valve area;

[0070] Figure 6 A longitudinal section is shown to illustrate another embodiment of the fuel injection valve. Detailed Implementation

[0071] In the description of the accompanying drawings, the same reference numerals are used for the corresponding parts of the embodiments.

[0072] Figure 1 A longitudinal sectional view of an embodiment of a fuel injection valve 10.1 is shown, the fuel injection valve having a housing 12 extending along a longitudinal axis L. The housing 12 has a fuel inlet 21 and a nozzle body 13 with an injection valve seat 131. The nozzle body 13 also has a centrally arranged injection opening 132 through which fuel can be discharged from the nozzle body 13 to inject fuel into the combustion chamber of an internal combustion engine. A fuel chamber 22 extends within the housing 12 from the fuel inlet 21 to the injection valve seat 131. A cap 14 is arranged at the downstream end of the nozzle body 13, extending to cover the central injection opening 132 of the nozzle body 13 and having a concentric opening 141. The cap 14 is arranged such that an axial clearance exists between the cap 14 and the nozzle body 13.

[0073] A control piston 51 is arranged in the housing 12 such that it can be adjusted along the longitudinal axis L. A control pressure spring 52 acts on the control piston 51 with a closing force toward the injection valve seat 131. The control piston 51 is guided in a guide sleeve 18 at its end section opposite the injection valve seat 131, and one end of the control pressure spring 52 is supported against the guide sleeve.

[0074] The fuel injection valve 10.1 also has a hydraulic control device with an intermediate valve 53 for controlling the adjustment of the control piston 51.

[0075] The nozzle needle 61 is arranged in the nozzle body 13 at the end of the control piston 51 facing the injection valve seat 131. The nozzle needle 61 abuts against the control piston 51 with its end face facing away from the injection valve seat 131, thereby pressing the end face of the control piston 51 facing the injection valve seat 131 by the injection pressure spring 62.

[0076] The housing 12 also includes an actuator housing 16 in which an electromagnetically actuated actuator device 43 is housed. An intermediate body 15 is adjacent to the actuator housing 16, and a portion of a control pressure spring 52 and a control piston 51 is disposed within this intermediate body. A nozzle body 13 is adjacent to the downstream end face of the intermediate body 15, thereby allowing the intermediate body 15 and the nozzle body 13 to be releasably fastened to the actuator housing 16 by a cap nut 17. Therefore, the nozzle body 13 and the nozzle needle 61 can be replaced by loosening the cap nut 17. A low-pressure control fluid return 42 is also disposed in the housing 12, the function of which will be described below. Figure 5 Further description.

[0077] Figure 2 It shows Figure 1 Enlarged view of the longitudinal section. The intermediate body 15 has a central guide hole 151 in which the adjusting section 512 of the control piston 51, located at its end facing the injection valve seat 131, is guided in a sliding fit. A control pressure spring 52, which applies a closing force to the control piston 51 in the direction toward the injection valve seat 131, rests its lower end against the shoulder 511 of the control piston 51 and its upper end against the guide sleeve 18, in which the guiding section 514 of the control piston 51 is guided in a sliding fit.

[0078] The downstream end face 513 of the control piston 51 and the upstream end face 611 of the nozzle needle 61 contact each other, thereby pressing the nozzle needle 61 against the injection pressure spring 62 of the control piston 51, with its lower end resting on the shoulder 134 of the nozzle body 13 and its upper end resting on the shoulder 612 of the nozzle needle 61. The upstream end face 611 of the nozzle needle 61 has a larger area than the downstream end face 513 of the control piston 51. However, in some embodiments, the upstream end face of the nozzle needle may also have a smaller area than the downstream end face of the control piston. Due to the individual design of the nozzle needle 61 and the control piston 51, as well as the design of the end faces 611 and 513, there are tolerances in the radial orientation of the nozzle needle 61 and the control piston 51 relative to each other. In particular, the nozzle needle 61 and the nozzle body 13 do not need to be precisely aligned with the guide hole 151 of the intermediate body 15, which is necessary, for example, in the case of a one-piece control injection piston. This simplifies the replacement of the nozzle needle 61 and the nozzle body 13.

[0079] The nozzle needle 61 is guided in the needle guide section 133 of the nozzle body 13 and has a plurality of recesses 613 extending in the longitudinal direction L of the nozzle needle 61 and opening radially outward, through which fuel can flow through the nozzle needle 61 in the longitudinal direction L.

[0080] The intermediate valve 53 has a mushroom-shaped intermediate valve member 54 and is designed to move the control piston 51 along the longitudinal axis, so that the control piston 51 can move the nozzle needle along the longitudinal axis.

[0081] Figure 3 It shows Figure 1 Another longitudinal section of the fuel injection valve 10.1, wherein the cross-sectional plane is relative to Figure 1 It is rotated 90° about the longitudinal axis L. The housing 12 has a control fluid inlet 31 and a high-pressure control chamber 32 connected to the control fluid inlet 31. A portion of the high-pressure control chamber 32 is located in the intermediate body 15, and another portion is located in the actuator housing 16.

[0082] For gaseous fuels, such as hydrogen or methane, the gas injection pressure is typically relatively low. For example, the gas injection pressure for hydrogen can range from about 10 to 60 bar, and in some cases up to about 100 bar. For methane, the gas injection pressure can also be within these ranges, exceeding about 100 bar in other specific cases, and reaching about 250 bar in even more specific cases. The control fluid pressure in the high-pressure control chamber is typically about 70 to 200 bar higher than the gas injection pressure.

[0083] For liquid fuels, such as methanol or its derivatives, like dimethyl ether (DME) or oxymethyl ether (OME), or ammonia or diesel, fuel injection pressures are typically relatively high. For example, the fuel injection pressure for methanol or its derivatives (such as DME or OME) can be around 400-600 bar, and in some cases up to about 1100 bar. The control fluid pressure in the high-pressure control chamber is typically about 100-300 bar higher than the fuel injection pressure. For ammonia, the fuel injection pressure is typically above about 1000 bar, and in some cases up to 1300 bar. Similar to diesel, the fuel injection pressure can vary depending on engine load and engine speed, and therefore can be below about 1000 bar in some cases. The control fluid pressure in the high-pressure control chamber is typically 10-20% higher than the fuel injection pressure. Therefore, for ammonia, the control fluid pressure in the high-pressure control chamber can be similar to that of diesel.

[0084] A leakage discharge channel 72 is arranged in the housing 12, which discharges leaks occurring in the guide hole 151 to the leakage outlet 73. The leakage discharge channel 72... Figure 4 The enlarged view shows this again. The guide hole 151 of the intermediate body 15 has a circumferential annular space 71, from which the leakage discharge channel 72 extends to the leakage outlet 73 (in...). Figure 3 (as shown in the figure) so that even though the adjusting section 512 of the control piston 51 is slidingly fitted, leakage occurring through the guide hole 151 can be discharged, and fluid separation between the high-pressure control chamber 32 and the fuel chamber 22 can be ensured or improved.

[0085] In some embodiments, the leakage discharge passage 72 may have a check valve (not shown) designed to open at an opening pressure between the control fluid inlet pressure of the high-pressure control chamber 32 and the fuel chamber pressure of the fuel chamber 22, preferably closer to the fuel chamber pressure than the control fluid inlet pressure.

[0086] In some embodiments, for gaseous fuels (such as hydrogen or methane), where the fuel chamber pressure is relatively low, the low-pressure control fluid return can be combined with a leak discharge channel. The low-pressure control fluid return and the leak discharge channel can then share a common control fluid outlet. The low-pressure control fluid return pressure will be the same as the leak discharge channel return pressure, which corresponds to the check valve opening pressure. With this design, one outlet can be advantageously omitted.

[0087] The intermediate body 15 has a transverse wall 152 that axially defines the high-pressure control chamber 32. The transverse wall 152 also provides spatial separation between the high-pressure control chamber 32 and the fuel chamber 22. The transverse wall 152 of the intermediate body 15 and the adjusting section of the control piston 51 (which is guided in a guide hole 151 in a sliding fit) achieve fluid separation between the high-pressure control chamber 32 and the fuel chamber 22.

[0088] Figure 5 It shows Figure 4 A further enlarged view of the intermediate valve 53 region. The intermediate valve 53 has a mushroom-shaped intermediate valve member 54 with a head 541 and a shaft 542. The shaft 542 is guided in a guide recess of the intermediate member 56. A guide sleeve 18 and a guide section 514 of the control piston, together with the intermediate member 56, define a control chamber 55. The intermediate valve 53 has an intermediate valve seat formed on the side of the intermediate member 56 facing the head 541, which is designed to interact with the head 541 in a sealing manner. The intermediate valve member 54 is axially movable between a control open position and a control closed position. In the control open position, the first connection between the control fluid inlet 321 connected to the high-pressure control chamber 32 and the control chamber 55 is released. In the control closed position, the first connection between the control fluid inlet 321 and the control chamber 55 is interrupted. Furthermore, in the control closed position, the control chamber 55 is separated from the valve chamber 44, except for the throttling passage 544. The valve chamber 44 is raised or lowered. Figure 1 The actuator 43 shown in the diagram has a push rod 431 that is either connected to or disconnected from the low-pressure control fluid return 42. The intermediate valve member 54 also has a port 543 that connects to the valve chamber 44 and is adjacent to the throttling passage 544.

[0089] The design of intermediate valve 53 substantially corresponds to the embodiments shown in publications WO2016 / 041739A1, WO2020 / 260285A1, or WO2021 / 165275A1, the disclosures of which are incorporated herein by reference. However, other known hydraulic control devices, such as those shown in WO2021 / 110663A1 or EP0753658B1, may also be used for intermediate valve 53, the disclosures of which are incorporated herein by reference.

[0090] Figure 6 A longitudinal sectional view of another embodiment of a fuel injection valve 10.2 is shown. The housing 12 has a nozzle body 13, an intermediate body 15, and an actuator mount 16, the nozzle body 13 and intermediate body 15 being releasably fastened to the actuator mount by a cap nut 17. A nozzle needle 61 is guided in the downstream region, within a needle guide section 133 of the nozzle body 13, and has a plurality of longitudinally extending and radially outwardly opening recesses.

[0091] and Figure 1-5 Compared to the fuel injection valve shown, the nozzle body 13 has a guide hole 135 in which the adjusting section 614 of the nozzle needle 61 and the adjusting section 512 of the control piston 51 are guided in a sliding fit. Because the adjusting section 614 of the nozzle needle 61 is guided in the guide hole 135, embodiments in which the nozzle needle 61 is not guided in the section 133 of the nozzle body 13 are also feasible. In these embodiments, a gap exists between the nozzle needle 61 and the lower section 133 of the nozzle body 13, through which fuel can flow.

[0092] Between the control piston 51 and the nozzle needle 61, an adjusting chamber 136 exists in the nozzle body 13. This adjusting chamber is radially defined by the nozzle body 13 and axially defined by the control piston 51 and the nozzle needle 61, and is fluid-closed. The guide orifice 135 has an annular space 71, such as... Figure 3 and Figure 4 In one embodiment, the leakage discharge channel extends from the annular space to the leakage outlet ( Figure 6 (Not visible in the center), and leakage occurring in the guide hole 135 can be discharged through this annular space.

[0093] As an alternative to the annular space 71, the leakage can also be discharged from the regulating chamber 136, making the annular space 71 unnecessary.

[0094] During injector assembly, slight misalignment may occur between the nozzle body 13, intermediate body 15, and actuator housing 16, for example, within a few hundredths of a millimeter. Because the adjusting section 512 of the one-piece control piston 51 is guided in a tight sliding fit within the nozzle body 13, and because the guide sleeve 18 for controlling the piston 51 is located within the actuator housing 16, the guide sleeve 18 for controlling the piston 51 is not tightly guided in the radial direction. Figure 6 As shown, the guide sleeve 18 therefore has a radial clearance with the actuator housing 16.

[0095] The high-pressure control chamber 32 is axially defined by the end face of the nozzle body 13 adjacent to the intermediate body 15. The adjusting sections 512 and 614 of the control piston 51 and the nozzle needle 61, which are guided in the guide hole 135 in a sliding fit, realize fluid separation between the high-pressure control chamber 32 and the fuel chamber 22.

[0096] The nozzle needle 61 engages with the injection valve seat 131 of the nozzle body 13 to inject fuel into the combustion chamber of the internal combustion engine. For this purpose, a plurality of eccentrically arranged injection openings 132 are arranged in the nozzle body 13 downstream of the injection valve seat 131. Figure 6 The arrangement of the injection opening 132 shown is generally advantageous for liquid fuels.

[0097] Figure 1-5 The fuel injection valve 10.1 shown is particularly advantageous for gaseous fuels, while Figure 6 The fuel injection valve 10.2 shown is specifically designed for use with liquid fuels. Depending on the requirements of the fuel used, the nozzle body 13 and nozzle needle 61 can be replaced in fuel injection valves 10.1 and 10.2. On the other hand, hydraulic control with intermediate valve 53 can be retained regardless of the fuel used.

[0098] Several alternative, targeted green and climate-neutral fuels typically have poor ignition characteristics and may require relatively high ignition energy for clean combustion in internal combustion engines. This is especially true if the combustion process, like most large engines, involves autoignition and simultaneous high compression, such as in diesel engines. Since high compression leads to higher engine efficiency, i.e., lower fuel consumption, this can result in significant operating cost savings for large engines that typically operate at high loads for thousands of hours per year.

[0099] To ignite the alternative fuel during auto-ignition, a small amount of diesel fuel is typically injected under high pressure. This can be optimally provided by a micro-ignition injector or by a jet injector that allows the engine to run on diesel fuel up to full load and provides only a small ignition jet to ignite the alternative fuel when the engine is under high load with the alternative fuel.

[0100] Therefore, this article focuses on Figure 1-6 The hydraulic control disclosed in the fuel injection valve shown can also be advantageously operated with diesel fuel. Thus, a third separate control fuel can be advantageously omitted.

Claims

1. A fuel injection valve (10.1, 10.2) for intermittently injecting fuel into the combustion chamber of an internal combustion engine, said fuel injection valve comprising: A housing (12) extending along a longitudinal axis (L) has a control fluid inlet (31), a fuel inlet (21), and a nozzle body (13) with an injection valve seat (131). A high-pressure control chamber (32) is arranged in the housing and connected to the control fluid inlet. A fuel chamber (22) is arranged in the housing and extends from the fuel inlet to the injection valve seat. A control piston (51) arranged in the housing for adjustment along the longitudinal axis is acted upon by a control pressure spring (52) with a closing force toward the injection valve seat. A hydraulic control device (53) for controlling the adjustment of the control piston along the longitudinal axis. A nozzle needle (61) is disposed at one end of the control piston facing the injection valve seat. The nozzle needle is at least partially disposed in the nozzle body and is designed to interact with the injection valve seat to inject fuel into the combustion chamber of the internal combustion engine. The nozzle needle is movable by adjusting the control piston along the longitudinal axis.

2. The fuel injection valve (10.1, 10.2) according to claim 1, characterized in that, The high-pressure control chamber (32) and the fuel chamber (22) are fluid-separated.

3. The fuel injection valve (10.1, 10.2) according to claim 1 or 2, characterized in that, The fuel injection valve has an intermediate body (15), in which the control piston (51) and the high-pressure control chamber (32) are at least partially arranged, and the nozzle body (13) is adjacent to the downstream end face of the intermediate body.

4. The fuel injection valve (10.1, 10.2) according to claim 3, characterized in that, The nozzle body (13) or the intermediate body (15) has guide holes (151, 135), and the adjustment section (512) of the control piston (51) arranged at its end facing the injection valve seat (131) and / or the adjustment section (614) of the nozzle needle (61) arranged at its end opposite to the injection valve seat are guided in the guide holes in a sliding fit.

5. The fuel injection valve (10.1, 10.2) according to claim 4, characterized in that, The guide holes (151, 135) have a circumferential annular space (71), and the fuel injection valve has a leakage outlet (73) and a leakage discharge passage (72) extending from the annular space to the leakage outlet.

6. The fuel injection valve according to claim 5, characterized in that, The leakage discharge channel has a check valve designed to open at an opening pressure between the control fluid inlet pressure and the fuel chamber pressure, preferably closer to the fuel chamber pressure than the control fluid inlet pressure.

7. The fuel injection valve according to claim 6, characterized in that, The opening pressure is less than 10% or about 10% higher than the fuel chamber pressure.

8. The fuel injection valve according to claim 6 or 7, characterized in that, The check valve is located inside the housing.

9. The fuel injection valve according to claim 6 or 7, characterized in that, The check valve is located outside the housing.

10. The fuel injection valve (10.1) according to any one of the preceding claims, characterized in that, A jet pressure spring (62) is arranged in the nozzle body (13), which presses the nozzle needle (61) against the control piston (51).

11. The fuel injection valve (10.2) according to any one of the preceding claims, characterized in that, A fluid-closed regulating chamber (136) is arranged between the control piston (51) and the nozzle needle (61), the regulating chamber being radially defined by the nozzle body (13) or the intermediate body and axially defined by the control piston (51) and the nozzle needle (61).

12. The fuel injection valve (10.1, 10.2) according to any one of the preceding claims, characterized in that, The fuel injection valve has an actuator housing (16), and the nozzle body (13) is preferably releasably fastened to the actuator housing by means of a cap nut (17), such that the nozzle body and the nozzle needle (61) are replaceable.

13. The fuel injection valve (10.1, 10.2) according to any one of the preceding claims, characterized in that, The nozzle needle (61) is guided in the needle guide section (133) of the nozzle body (13), wherein the nozzle needle preferably has at least one recess (613) that extends in the longitudinal direction and opens radially outward.

14. The fuel injection valve (10.1) according to any one of the preceding claims, characterized in that, The nozzle body (13) has concentric injection openings (132).

15. The fuel injection valve (10.2) according to any one of claims 1 to 13, characterized in that, The nozzle body has multiple spray openings (132) arranged eccentrically.

16. The fuel injection valve (10.1) according to any one of the preceding claims, characterized in that, A cap (14) is arranged at the downstream end of the nozzle body (13), the cap extending to cover at least one injection opening (132) and having a concentric or at least one eccentric opening (141).

17. The fuel injection valve (10.1) according to any one of the preceding claims, characterized in that, The fuel chamber (22) has a fuel supply section, the diameter of which is larger than the diameter of the control fluid supply section of the high-pressure control chamber (32).

18. The fuel injection valve (10.1, 10.2) according to any one of the preceding claims, characterized in that, The hydraulic control device (53) is designed to move the control piston (51) along the longitudinal axis (L) by changing the pressure in the control chamber (55), wherein the hydraulic control device includes an intermediate valve (53) having an intermediate valve member (54) that opens a first connection between the control fluid inlet (321) connected to the high-pressure control chamber (32) and the control chamber (55) in a controlled open position, and interrupts the first connection between the control fluid inlet and the control chamber in a controlled closed position, and separates the control chamber from the valve chamber (44) except for the throttle passage (544), wherein the fuel injection valve includes an electromagnetically actuated actuator device (43) for connecting the valve chamber to the low-pressure control fluid return (42) and separating the valve chamber from the low-pressure control fluid return.

19. The fuel injection valve (10.1, 10.2) according to claim 18, characterized in that, The control piston (51) has a guide section (514) at one end facing away from the injection valve seat (131), the guide section being guided in a guide sleeve (18) in a sliding fit, wherein the fuel injection valve has an intermediate component (56), the intermediate component together with the guide sleeve and the control piston defining the control chamber (55), wherein the intermediate valve member (54) is mushroom-shaped and has a shaft (542) and a head (541) guided in a guide recess of the intermediate component, wherein the intermediate valve (53) has an intermediate valve seat formed on the side of the intermediate component facing the head and engaging with the head.

20. The fuel injection valve according to claim 19, characterized in that, The intermediate valve component releases the second connection between the control fluid inlet and the valve chamber in the controlled open position of the intermediate valve component, and interrupts the second connection between the control fluid inlet and the valve chamber in the controlled closed position of the intermediate valve component.

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