Nozzle, hydrogen injector and method for supplying hydrogen to combustion chamber of internal combustion engine

Abstract

The invention relates to a nozzle (2) for supplying a combustion chamber of an internal combustion engine with hydrogen, comprising a housing (3) and a needle valve (5) which can be slid in the housing and which comprises a shaft (6) and a valve disk (7) which adjoins the shaft and expands towards a nozzle opening, the needle valve (5) and the valve disc (7) are arranged in the housing (3) such that an annular flow channel (4) is formed between the needle valve (5) and the inner wall (10) of the housing (3), which flow channel extends from a channel inlet (8) at the transition between the shaft (6) of the needle valve (5) and the valve disc (7) to a channel outlet (9) at the end of the needle valve (5), the opening area of the channel inlet (8) being variable as a result of the slidability of the needle valve (5), and the opening area of the channel outlet (9) being variable as a result of the slidability of the needle valve (5). The channel outlet (8) at the end of the needle valve (5) has a constant cross-sectional area over the entire range of movement of the needle valve (5).

Description

Technical Field

[0001] This invention relates to nozzles configured for supplying hydrogen to the combustion chamber of an internal combustion engine, particularly a reciprocating piston engine. The invention also relates to hydrogen injectors for internal combustion engines, and methods for supplying hydrogen to the combustion chamber of an internal combustion engine designed as a reciprocating piston engine. Background Technology

[0002] DE 10 2021 208 649 A1 discloses a gas injector for injecting hydrogen, which includes a shut-off element that opens and closes a through opening at a sealing seat. The shut-off element of a known gas injector includes a valve needle and a valve disc, wherein an insulating device is located on the valve disc, arranged on the side of the valve disc facing the combustion chamber of an internal combustion engine. The valve seat of the gas injector according to DE 10 2021 208 649 A1 includes a plurality of through holes through which hydrogen can flow in the direction of the sealing seat.

[0003] DE 10 2021 212 897 A1 discloses an injector for an internal combustion engine, which is also configured for injecting hydrogen, wherein the conical valve sealing surface of a valve needle interacts with the sealing surface of a valve body. According to DE 102021 212 897 A1, the valve needle is radially guided and is designed to be hollow within the valve body.

[0004] An injection device for directly injecting gaseous fuel into the combustion chamber of an internal combustion engine, as described in DE 10 2021 212 503 A1, includes an inlet valve and a fuel line section for the gaseous fuel located near the valve seat of the inlet valve. According to DE 10 2021 212 503 A1, the gas injection, provided at a pressure of approximately 700 bar, should be performed in a pressure-controlled manner.

[0005] Another gas injector for injecting gaseous fuel is known from DE 10 2014 224 344 A1. This gas injector, i.e., the fuel injector, has an outwardly opening valve closing element and a flow guiding element for forming a gas jet. Using the gas injector according to DE 10 2014 224 344 A1, it should be possible to form a gas jet with a defined geometric relationship to the axial axis of the gas injector. Summary of the Invention

[0006] Compared with the prior art mentioned above, the present invention is based on the purpose of further developing hydrogen injection in internal combustion engines, wherein the objective is to achieve at least approximately homogeneous mixture formation within the maximum possible range of different operating states of the engine.

[0007] According to the invention, this objective is achieved by a nozzle having the features of claim 1. This nozzle is adapted to be installed in a hydrogen injector according to claim 6. This objective is also achieved by a method according to claim 7 for supplying hydrogen to the combustion chamber of an internal combustion engine designed as a reciprocating piston engine.

[0008] A nozzle designed to supply hydrogen to the combustion chamber of an engine includes a housing and a nozzle needle capable of displacement within the housing. The nozzle needle includes a shaft and an adjacent valve disc that widens toward the nozzle opening, forming an annular flow channel between the nozzle needle and the inner wall of the housing, widening in the direction of hydrogen flow. This flow channel extends from a channel inlet located at the transition between the nozzle needle's shaft and the valve disc to a channel outlet located at the end of the nozzle needle. Here, the opening area of ​​the channel inlet is variable due to the displacement of the nozzle needle, while the channel outlet at the end of the nozzle needle has a constant cross-sectional area throughout the entire adjustment range of the nozzle needle.

[0009] It has been shown that the design of the nozzle, including the nozzle needle which can be displaced along its longitudinal direction, allows for targeted switching between different flow states of hydrogen injected into the combustion chamber of an internal combustion engine by means of direct injection.

[0010] The hydrogen flow pattern at the nozzle outlet depends on the adjustment of the nozzle needle, the hydrogen pressure at the nozzle channel inlet, and the back pressure in the combustion chamber, assuming that hydrogen is supplied to the combustion chamber only after the inlet valve is closed. During the short period available for gaseous fuel supply, the cross-sectional area of ​​the channel inlet can be altered by longitudinally shifting the nozzle needle, causing the flow to reverse within the nozzle after the channel outlet. Therefore, a control cross-section is provided at the channel inlet, i.e., at the narrowest point of the nozzle gap. Overall, the nozzle is designed as a supersonic nozzle.

[0011] The transition between different flow states occurs while maintaining a constant geometry at the channel outlet, which is positioned at the tip of the nozzle needle. Sequentially adjusting different flow conditions during the injection process significantly contributes to the uniform distribution of gaseous fuel in the combustion chamber. Flow states that can be adjusted in a targeted manner can be viewed as hollow conical jets that differ from each other in their opening angles. Here, one of the hollow conical jets can degenerate into a practically non-fanning straight jet.

[0012] Generally, a method for supplying hydrogen to the combustion chamber of an internal combustion engine designed as a reciprocating piston engine is characterized by the delivery of hydrogen through a nozzle designed according to claim 1 and having a movable nozzle needle, wherein, downstream of the valve disc of the nozzle needle, in a first adjustment of the nozzle needle, a hydrogen flow supported against the inner wall of the nozzle in the sense of a coanda flow is generated at a corresponding point, and in a second adjustment of the nozzle needle, a hydrogen flow separated from the inner wall is generated at the corresponding point. The flow state given in the first adjustment is particularly suitable for producing a wide fan-shaped jet, while the flow separation in the second adjustment means that the hydrogen exiting the nozzle flows into the combustion chamber of the engine in the form of a relatively narrow jet. By adjusting the nozzle needle multiple times during the piston stroke of the reciprocating piston engine, the flow can be switched multiple times between a coanda flow, i.e., a flow supported against the housing wall, and an unsupported flow, especially when the inlet valve is closed.

[0013] Specifically, the transition between different flow states of the hydrogen to be injected can be controlled by changing the ratio between the variable cross-sectional area of ​​the flow channel at the inlet located at the transition between the nozzle needle shaft and the valve disc, and the cross-sectional area of ​​the same flow channel at the outlet located on the planar end surface of the valve disc. Alternatively, the transition between different flow states of hydrogen can be influenced by increasing the pressure in the combustion chamber of the internal combustion engine. Here, a higher internal cylinder pressure than the static pressure of the hydrogen flowing from the nozzle favors the flow supported against the curved inner wall of the nozzle, i.e., the Coanda flow.

[0014] According to possible embodiments of the nozzle, the valve disc of the nozzle needle terminates at the channel outlet with a planar end surface, which remains within the housing during any adjustment of the nozzle needle. Here, the central axis of the nozzle needle's shaft represents the surface normal relative to the plane containing the end surface. Regardless of the specific shape of the nozzle needle, it can consist of one or more parts.

[0015] The nozzle housing may have a cylindrical region of inner wall in a section protruding beyond the valve disc of the nozzle needle, and an adjacent curved, widened end section extending to the end face plane at the outlet side opening of the housing. If the nozzle operates with a targeted Coanda flow, the hydrogen flow will be supported against the housing wall, particularly in the end section. Conversely, a separated flow state means that the flow in the end section does not follow the contour of the inner wall of the housing, but is generally axially aligned relative to the longitudinal direction of the nozzle needle axis. Specifically, the tangent applied to the end section of the housing in the cross-sectional plane containing the longitudinal axis of the nozzle needle intersects the surface normal of the end face plane at an angle not exceeding 60°, starting from zero and increasing in the direction of hydrogen flow.

[0016] The inner wall of the housing is characterized by multiple curved curves in cross-section, extending from a first cylindrical wall section surrounding the axis of the nozzle needle to the aforementioned end face plane. These curves include a first convex section adjacent to the first cylindrical wall section, a concave section adjacent to the first convex section, a second cylindrical section adjacent to this section whose diameter is larger than that of the first cylindrical section, and a convex, curved end section adjacent to the second cylindrical section. Here, the displaceability of the nozzle needle can be limited such that the planar end surface of the nozzle needle's valve disc can only displace within the cylindrical section described by the second cylindrical section.

[0017] This nozzle is suitable not only for use in hydrogen injectors but also for use in injectors for other gaseous fuels, such as methane or ammonia. As for the actuator used to adjust the nozzle needle, proven solutions described in the prior art can be utilized. In addition to electromagnetic actuators, piezoelectric actuators can also be used to actuate the nozzle needle, for example, in fuel injectors. Attached Figure Description

[0018] In the following, exemplary embodiments of the present invention will be explained in more detail with reference to the accompanying drawings. In the drawings: Figure 1 The image shows a nozzle in its first adjustment for supplying hydrogen to the combustion chamber of an internal combustion engine. Figure 2 The basis for the second regulation is shown. Figure 1 The nozzle, Figure 3 The basis for the third regulation is shown. Figure 1 The nozzle, Figure 4 It shows that according to Figure 1 A diagram of the first operating mode of the nozzle. Figure 5 It shows that according to Figure 1 A diagram of the second operating mode of the nozzle. Figure 6 The internal combustion engine shown has according to Figure 1 A schematic diagram of the nozzle section. Detailed Implementation

[0019] A hydrogen injector, generally indicated by reference numeral 1, is provided for use in a hydrogen-operated gas engine (not further shown). In this example, the gas engine is a reciprocating piston engine of a motor vehicle. Alternatively, the hydrogen injector 1 may be an injector for, for example, a stationary gas engine in a combined heat and power generation system. The actuator of the hydrogen injector 1, i.e., the fuel injector, is not shown. Figures 1 to 3A cross-section of the nozzle 2 of the hydrogen injector 1 is shown. A device located upstream of the nozzle 2 for reducing the pressure of the hydrogen to be burned in the gas engine is not shown.

[0020] Fuel injector 1, i.e., gas injector, has the function of... Figures 1 to 3 The housing 3 is only partially visible. The nozzle needle 5 is displaceably guided within the housing 3, i.e., the injector housing. The axis of the nozzle needle 5 is indicated by reference numeral 6, and the valve disc of the nozzle needle 5 is indicated by reference numeral 7. An annular flow channel 4 is formed between the valve disc 7 and the inner wall of the housing 3, in the direction of hydrogen flow— Figures 1 to 3 In the arrangement shown, the width increases from right to left, with the inner wall of the housing generally indicated by reference numeral 10. The channel inlet 8 is defined as the narrowest point of the nozzle cross-section, located at the transition between the shaft 6 of the nozzle needle 5 and the valve disc 7. By definition, the channel outlet, indicated by reference numeral 9, is located at the combustion chamber side end of the valve disc 7, which takes the form of the end face 13 of the valve disc 7, also referred to as the end surface. In this example, the end surface 13 has a planar shape, where the central axis of the shaft 6 represents the surface normal of the end surface 13. The diameter of the shaft 6 is indicated by reference numeral d6. The diameter is indicated by reference numeral d3. Figure 1 The diameter of the shell 3 shown does not necessarily represent the maximum size of the shell 3; rather, the diameter d3 refers only to the cylindrical section of the shell 3 shown.

[0021] The valve disc 7 of the nozzle needle 5 has a curved surface segment 11 and an adjacent cylindrical surface segment 12, wherein the cylindrical surface segment 12 extends to an end surface 13 except for any rounded edges. The diameter of the valve disc 12, indicated by reference numeral d12, corresponds to the diameter of the cylindrical surface segment 12, and in this example, the diameter of the valve disc is greater than 1.5 times, but not more than four times, the diameter d6 of the shaft 6.

[0022] The end face plane 14, applied to the end face of the housing 3 on the outlet side of the hydrogen injector 1, is a plane representing the end face plane. This end face plane 14 is parallel to the end face plane 13 of the valve disc 7, and there is a distance a2_7 between it and the end face plane 14. During any adjustment of the hydrogen injector 1, the end face 13 is located within the interior formed by the housing 3.

[0023] In the section of the housing 3 that protrudes beyond end face 13 and extends to end face plane 14, the housing 3 has a curved end section 15, which, as part of the inner wall 10, abuts the outer cylindrical region 16 of the inner wall 10. During each adjustment of the nozzle needle 5, at least one region of the cylindrical surface section 12 of the valve disc 7, abutting the end face 13, is concentrically arranged within the outer cylindrical region 16 of the inner wall 10, such that the geometry of the channel outlet 9 located on the valve disc 7 of the nozzle needle 5 remains unchanged.

[0024] In the direction of axis 6, the outer cylindrical region 16 of the inner wall 10 is incorporated into the concave wall section 18, which is adjacent to the convex wall section 17. The convex wall section 17 located in the region of the channel entrance 8 is adjacent to the inner cylindrical region of the inner wall 10, indicated by reference numeral 19. In an exemplary embodiment, the diameter of the inner cylindrical region 19, indicated by reference numeral d19, is at least one-third but no more than 80% of the diameter of the outer cylindrical region 16 of the inner wall 10, indicated by reference numeral d16.

[0025] exist Figure 1 In the adjustments outlined herein, nozzle 2 is opened as wide as possible, i.e., the channel inlet 8 is adjusted to its maximum cross-sectional area. In this adjustment, distance a2_7 is minimized. Compared to all other possible adjustments of nozzle 2, hydrogen flows at the highest velocity at channel outlet 9, where it exists as an underexpanded jet. The hydrogen jet expands inward in the direction of the central axis of nozzle 2, i.e., this is accompanied by the jet separating from the inner wall 10 at the transition between the outer cylindrical region 16 and the end section 15. Therefore, hydrogen is introduced into the combustion chamber as a narrow, at most slightly widened, hollow jet emerging from the annular gap formed between the cylindrical surface section 12 of the valve disc 7 and the same cylindrical region 16 of the inner wall 10 of the housing 3.

[0026] If the flow cross-section at the channel inlet 8 is narrowed by the retracting nozzle needle 5, thus leading to Figure 2 The adjustment shown indicates that the expansion ratio within flow channel 4 is... Figure 1 The expansion ratio shown in the adjustment is more extreme. This results in a lower static outlet pressure of hydrogen at channel outlet 9, meaning the flowing hydrogen has a lower tendency to expand towards the central axis of nozzle 2. Conversely, the hydrogen flow remains supported against the inner wall 10 of the housing 3 in the end region 15. This Coanda effect ensures that the hydrogen jet forms a hollow conical jet with a large opening angle. The angle denoted by α between the tangent applied to the curved end section 15 and the end face plane 14 is 45° ± 15°. Even a slight, limited axial movement of the nozzle needle 5 is sufficient to divert the hydrogen flow from the nozzle 2 according to the... Figure 1 The regulated separated flow is changed according to Figure 2 The forced Coanda flow during regulation. Finally, Figure 3 The closed state of nozzle 2 is shown.

[0027] When operating an internal combustion engine equipped with a hydrogen injector 1, there are various switching methods between the separated hydrogen flow on one hand and the flow applied in the sense of a Coanda flow on the other hand, as described below based on Figure 4 and Figure 5 The explanation given.

[0028] Figure 4 and Figure 5The diagram illustrates the idealized dependence of various pressures, generally indicated by reference numeral p, and the stroke H of nozzle needle 5 on the crankshaft angle KW of the internal combustion engine. The compression stroke of the internal combustion engine, designed as a gasoline engine, is considered. IVC represents the closure of the inlet valve. SOI and EOI represent the start and end of the injection process, i.e., the direct injection of hydrogen into the combustion chamber. It is assumed that the internal combustion engine operates under forced intake, such as turbocharging. In the considered time window, the cylinder pressure pZ is increasing. The half-pressure setting, indicated by reference numeral HD, means that the pressure upstream of nozzle 2 is half the comparison pressure and occurs only after the injection EOI ends but before top dead center.

[0029] exist Figure 4 In the operating mode shown, the system switches between a separated hydrogen stream and a coanda stream multiple times during the compression stroke. With the start of SOI injection, nozzle needle 5... Figure 3 The closed position shown begins with an actuation speed that is at least approximately linear (e.g., Figure 4 (As shown) Open until the nozzle 2, indicated by the attached reference numeral MD, reaches its maximum opening, i.e., according to... Figure 1 Until the adjustment is made. Nozzle 2 remains in this state, thus injecting hydrogen in the form of a narrow, hollow jet, until the time point indicated by the attached reference numeral ST, which marks the beginning of the partial stroke of nozzle needle 5, i.e., the beginning of the retraction of nozzle needle 5. This partial closure of nozzle 2 also occurs at at least an approximately constant actuation speed, corresponding to the opening of nozzle 2. This reduces the pressure of the hydrogen injected from nozzle 2. If the hydrogen pressure p has dropped to approximately the level of the pressure pZ commonly present in the combustion chamber, the hydrogen flow changes to a support flow, i.e., a coanda flow. This flow change is indicated by the attached reference numeral SW.

[0030] exist Figure 4 In the operating mode shown, it is not intended that nozzle 2 be completely closed subsequently. Instead, a coanda flow is maintained for a short period of time, specifically ensuring that the area of ​​the combustion chamber near the wall is filled with hydrogen. After the channel inlet 8 has been nearly but not completely closed, the nozzle needle 5 moves again in the direction of full opening of nozzle 2. The resulting release of a larger opening cross-section at the channel inlet 8 causes another flow change SW, this time again becoming a separated hydrogen flow. The opening process continues until the maximum opening MD of nozzle 2 is reached again. Figure 4 As can be seen, the described process is repeated multiple times, alternating between a phase with a separated flow and a phase in which a coanda flow is present. Although no airflow enters the combustion chamber, this method achieves very good mixing of air and hydrogen.

[0031] and Figure 4 The operating mode shown is the opposite, according to Figure 5The intention is to achieve a single switch between different flow states during the compression stroke, where initially a Coanda flow exists, followed by a separated flow as the cylinder pressure pZ increases. Upstream of nozzle 2, hydrogen is at rail pressure, which, in the case considered, is 20 bar, 30 bar, or 40 bar. The pressure is adjusted on the outlet side of nozzle 2 according to the rail pressure, which is... Figure 5 The figures are labeled P2, P3, or P4. For example... Figure 5 As shown, the higher the orbital pressure and therefore the higher the pressures P2, P3, and P4 on the outlet side of hydrogen injector 1, the later the flow change SW occurs.

[0032] Figure 6 The illustration shows various possible flow states in the combustion chamber 21 of an internal combustion engine, specifically a multi-cylinder reciprocating piston engine, generally indicated by reference numeral 20. The piston is indicated by reference numeral 22; the spark plug by reference numeral 23. The gas exchange valve of the internal combustion engine 20 is not shown.

[0033] The adjustable coanda flow is indicated by reference numeral CS, and can also be adjusted in a targeted manner and separated from the flow of the curved end section 15 having a narrow hollow jet form, indicated by reference numeral HS. The variation between the different flows CS and HS depends particularly on the static pressure at the end of the nozzle 2. Here, the static pressure is the pressure of the flowing hydrogen acting on the flow parallel surface, in this case the inner wall 10. The flow inside the combustion chamber 21, indicated by reference numeral CS, is not necessarily formed entirely as a narrow coanda flow. In any case, the coanda flow CS inside the nozzle 2 is supported against the inner wall 10 of the nozzle, particularly against the inner wall of the nozzle in the curved end section 15, which supplies hydrogen to the combustion chamber 21, particularly in the region near its wall, such as... Figure 6 It is presented in an idealized form.

[0034] On the other hand, if the hydrogen injector 1, including the nozzle 2, is operated such that the hydrogen flow in the end section 15 is separated from the wall, thereby forming a relatively sharp hollow jet HS that is mainly guided to the center of the combustion chamber 21, the pressure conditions are adjusted such that the static pressure of the hydrogen flowing out of the nozzle 2 is greater than the cylinder internal pressure acting in the combustion chamber 21.

[0035] Hydrogen gas is supplied to injector 1 at orbital pressures P2, P3, and P4, as already based on Figure 5The variations in orbital pressures P2, P3, and P4, as well as the changes in the area ratio of the channel cross-sections 8 and 9, affect the flow state of the hydrogen, resulting in either a Coanda flow (CS) or a hollow jet (HS) with a relatively small opening angle. In this context, the aforementioned area ratio is adjusted by the stroke of the nozzle needle 5. Furthermore, the flow state depends on the internal cylinder pressure. If the static outlet pressure of the hydrogen is less than the internal cylinder pressure, this results in a support flow with a large opening angle in the sense of a Coanda flow (CS).

[0036] To switch between different flow states, typically only one parameter needs to be changed. These parameters include the stroke of nozzle needle 5, the rail pressures P2, P3, and P4 (i.e., the gas pressure upstream of nozzle 2), and the cylinder internal pressure. This switching process can also be triggered in a targeted manner by adjusting two of the three parameters or by adjusting all three parameters simultaneously. In all cases, switching the flow state once or multiple times during the compression stroke significantly contributes to the efficient filling of combustion chamber 21 with hydrogen and its good mixing with air.

[0037] List of reference numerals 1. Hydrogen Injector 2 nozzles 3. Shell 4. Flow channel 5 Nozzle needles 6-axis 7 Valve disc 8 entrance channels 9-channel exit 10. Inner wall of the shell 11. Curved surface section of the valve disc 12. Cylindrical surface section of the valve disc 13. End surface and end face of the valve disc 14. The end face plane at the opening of the shell. 15. The curved end section of the shell 16 Outer cylindrical area of ​​inner wall 17. Convex wall section 18. Concave wall section 19. Wall section, inner cylindrical area of ​​the inner wall. 20 Internal Combustion Engine 21 Combustion Chamber 22 Pistons 23 Spark plugs α angle a2_7 Distance between the end face of the valve disc and the end face of the housing CS Coanda Flow d3 is the diameter of the shell. The diameter of the d6 axis d16 is the diameter of cylindrical region 16. d19 Diameter of cylindrical region 19 d12 is the diameter of the valve disc. End of EOI injection process H stroke HD Half Pressure Setting HS separated flow, narrow hollow jet IVC closes the inlet valve KW crankshaft angle Maximum opening of MD nozzle p pressure P2 nozzle outlet side pressure (at 20 bar rail pressure) Pressure at the P3 nozzle outlet side (at 30 bar rail pressure) P4 Pressure at the nozzle outlet (at 40 bar rail pressure) pZ Cylinder Pressure Start of the SOI injection process ST - Start of partial stroke SW flow changes

Claims

1. A nozzle (2) for supplying hydrogen to a combustion chamber, the nozzle having a housing (3) and a nozzle needle (5) which is displaceable in the housing (3) and comprises a shaft (6) and an adjoining valve disc (7), the valve disc widening towards a nozzle opening such that between the nozzle needle (5) and an inner wall (10) of the housing (3) an annular flow channel (4) is formed which widens in the flow direction of the hydrogen, the flow channel extending from a channel inlet (8) at a transition between the shaft (6) and the valve disc (7) of the nozzle needle (5) to a channel outlet (9) at an end of the nozzle needle (5), wherein Due to the displaceability of the nozzle needle (5), the opening area of ​​the channel inlet (8) is variable, while the channel outlet (8) located at the end of the nozzle needle (5) has a constant cross-sectional area throughout the entire adjustment range of the nozzle needle (5).

2. Nozzle (2) according to claim 1, characterized in that The valve disc (7) of the nozzle needle terminates at the channel outlet (9) with a planar end surface (13), which is located inside the housing (3) in any adjustment of the nozzle needle (5).

3. The nozzle (2) according to claim 1 or 2, characterized in that, In the section of the valve disc (7) that protrudes beyond the nozzle needle (5), the housing (3) has a cylindrical region (16) of the inner wall (10) and an adjacent curved, widened end section (15) that extends far to the end face plane (14) located at the outlet side opening of the housing (3).

4. The nozzle (2) according to claim 3, characterized in that, The tangent applied to the end segment (15) intersects the surface normal of the end face plane (14) at an angle (α) not exceeding 60°, the angle starting from zero and increasing along the flow direction.

5. The nozzle (2) according to claim 3 or 4, characterized in that, The inner wall (10) of the housing (3) is depicted in cross-section as a multi-bend curve extending from a first cylindrical wall section (19) surrounding the axis (6) of the nozzle needle (5) to the end face plane (14). The multi-bend curve includes a first convex section (17) adjacent to the first cylindrical wall section (19), a concave section (18) adjacent to the first convex section, a second cylindrical section (16) adjacent to the section (18), and a convexly curved end section (15) adjacent to the second cylindrical section (16).

6. A hydrogen injector (1) for an internal combustion engine, the hydrogen injector comprising a nozzle (2) according to claim 1.

7. A method for supplying hydrogen to the combustion chamber (21) of an internal combustion engine (20) designed as a reciprocating piston engine, wherein, Hydrogen is delivered through a nozzle (2) designed according to claim 1 and having a movable nozzle needle (5), wherein, downstream of the valve disc (7) of the nozzle needle (5), in a first adjustment of the nozzle needle (5), a hydrogen flow supported against the inner wall (10) of the nozzle (2) in the sense of a Coanda flow is generated at a corresponding point, and in a second adjustment of the nozzle needle (5), a hydrogen flow separated from the inner wall (10) is generated at a corresponding point.

8. The method according to claim 7, characterized in that, During the piston stroke, the nozzle needle (5) is adjusted several times to alternate between coanda flow and flow not against the wall support.

9. The method according to claim 7 or 8, characterized in that, The transition between different flow states is controlled by changing the ratio between the cross-sectional area of ​​the flow channel (4) at the channel inlet (8) at the transition between the shaft (6) of the nozzle needle (5) and the valve disc (7) and the cross-sectional area of ​​the flow channel (4) at the channel outlet (9) at the planar end surface (13) of the valve disc (7).

10. The method according to any one of claims 7 to 9, characterized in that, The transition between different flow states is particularly affected by the increased pressure in the combustion chamber (21) of the internal combustion engine (20).

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