Valve assembly, fluid injection valve and method for operating the fluid injection valve

Abstract

 A valve assembly (2) for a fluid injection valve (3) is disclosed. The valve assembly (2) has a longitudinal axis (L) and comprises a valve body (4) having a valve cavity (45) and a valve seat (40), a valve needle (1) and an armature (7), the valve needle (1) and the armature (7) being arranged in the valve cavity (45) in axially moveable fashion. The valve seat (40) has a first set of orifices (41) and a second set of orifices (42). The valve needle (1) comprises a tip portion (10), the tip portion (10) having a first section (11) and a second section (12). The first section (11) is operable to seal the first set of orifices (41). The second section (12) is operable to seal the second set of orifices (42) and is axially movable with respect to the first section (11). The armature (7) is operable to interact mechanically with the valve needle (1) for axially displacing the first section (11) away from the valve seat (40). Further, a fluid injection valve (3) and a method for operating the fluid injection valve (3) are disclosed.

Description

[0001] The present disclosure relates to a valve assembly for a fluid injection valve, to a fluid injection valve, and to a method for operating the fluid injection valve.

[0002] It is an object of the present disclosure to specify a valve assembly for a fluid injection valve and a method for operating the fluid injection valve which have a particular large working range with respect to the fluid doses to be dispensed during one injection event and which allow a particularly precise dosing of small fluid amounts.

[0003] This object is achieved by a valve assembly for a fluid injection valve and by a method for operating a fluid injection valve according to the independent claims. Advantages, advantageous embodiments and developments of the valve assembly, of a fluid injection valve comprising the valve assembly, and of the method are specified in the respective dependent claims.

[0004] According to one aspect, a valve assembly for a fluid injection valve is specified. According to another aspect, a fluid injection valve comprising the valve assembly is specified. According to yet another aspect, a valve needle for the fluid injection valve - more specifically, a valve needle for the valve assembly - is specified.

[0005] The fluid injection valve, in particular the valve assembly, may comprise a valve seat. The valve seat has a first set of orifices; in other words it has one first orifice or a plurality of first orifices. It further comprises a second set of orifices, i.e. a second orifice or a plurality of second orifices, different from the first orifice(s). The fluid injection valve and the valve assembly, respectively, are in particular operable to dispense fluid trough the first and second orifices.

[0006] The valve assembly in particular comprises the valve needle. The valve needle may expediently be provided for controlling fluid flow through the first and second sets of orifices by means of mechanical interaction with the valve seat.

[0007] The valve needle has a longitudinal axis. In particular the valve needle and the valve assembly share a common longitudinal axis. The longitudinal axis can also be a longitudinal axis of the fluid injection valve.

[0008] The valve needle comprises a tip portion. In particular, the valve needle extends along the longitudinal axis from a needle shaft to the tip portion. The tip portion has a first section and a second section. The first section of the tip portion is designed for sealing the at least one first orifice in the valve seat. The second section is designed for sealing the at least one second orifice in the valve seat. The second section is axially moveable with respect to the first section.

[0009] In one embodiment, the valve assembly comprises a valve body which has a valve cavity. The valve needle is preferably arranged in the valve cavity in axially moveable fashion. The valve seat may be in one piece with the valve body or it may be fixed to the valve body.

[0010] The valve assembly has a closing configuration. In the closing configuration, the first section of the tip portion is operable to seal the first set of orifices and the second section of the tip portion is operable to seal the second set orifices for preventing fluid flow from the valve cavity through the first and second sets of orifices.

[0011] The valve assembly further has a first opening configuration. In the first opening configuration, the valve assembly is operable to release fluid from the valve cavity trough the first set of orifices while the second section of the tip portion is operable to seal the second set of orifices also in the first opening configuration. The valve assembly is transferable from the closing configuration to the first opening configuration by means of an axial displacement of the first section of the tip portion of the valve needle relative to the valve body and to the second section of the tip portion in a direction away from the valve seat.

[0012] In addition, the valve assembly has a second opening configuration in which the valve assembly is operable to release fluid trough the first set of orifices and trough the second set of orifices. The valve assembly is transferable from the first opening configuration to the second opening configuration by means of an axial displacement of the second section of the tip portion of the valve needle relative to the valve body in a direction away from the valve seat. In one embodiment, the second section remains in the same axial position with respect to the first section at least during a portion of its axial movement for bringing the valve assembly from the first opening configuration to the second opening configuration. In other words, the first and second sections may at least partially move together away from the valve seat for transferring the valve assembly from the first opening configuration to the second opening configuration.

[0013] In this way, by means of the valve needle having the first and second sections of the needle tip which are axially displaceable with respect to each other, fluid can be dispensed from the valve assembly trough only a portion of the orifices in the valve seat, i.e. through the first set of orifices. In this way, the minimum amount of fluid which can be dispensed from the valve assembly is particularly low. Further, the dosing of small amounts of fluid is particularly precise, since the opening time during one injection event is larger as compared to a valve assembly where all orifices have to be opened also for dispensing small liquid amounts. Increased opening times, however, make the valve assembly more insensitive to tolerances of the opening and/or closing movements, for example. In addition, a particularly high working range of the valve assembly with respect to fluid amounts and working pressure is achievable with the valve needle of the present disclosure.

[0014] In one embodiment, the first section and the second section are arranged concentrically with respect to the longitudinal axis. In particular, the second section overlaps with the longitudinal axis. For example, the second section is a body of revolution having the longitudinal axis as a rotational axis. The first portion preferably surrounds a second section in a top view along the longitudinal axis. For example, the first section has a central opening in top view along the longitudinal axis in which central opening the second section is arranged. This design may be particularly advantageous with respect to the radial distribution of the fluid flow through the valve cavity of the valve assembly.

[0015] In one embodiment, the valve needle additionally comprises a spring element. The spring element is operable to bias the second section of the tip portion in the first axial direction, in particular with respect to the first section. Additionally or alternatively, the valve needle may comprise a stop element which is operable to limit axial displacement of the second section in the first axial direction with respect to the first section of the tip portion.

[0016] For example, the valve needle comprises a main body and the first section of the tip portion is in one piece with the main body. The needle cavity preferably extends in axial direction at least completely trough the first section of the tip portion. In one development, the needle cavity extends over the complete axial length of the main body. The central opening of the first section may be represented by a partial region of the needle cavity. The second section of the tip portion is in particular received in the needle cavity. In other words, the second section of the tip portion is arranged at least partially in the needle cavity. In an expedient development, the second section projects from the needle cavity - and preferably from the first section - in axial direction, in particular in the first axial direction.

[0017] In one embodiment, the spring element is arranged in the needle cavity. One end, in particular an end remote from the second section, of the spring element may be fixedly coupled to the main body, for example by means of a washer which is arranged in the needle cavity and rigidly fixed to the main body, for example by means of a friction fit.

[0018] In one embodiment, the stop element is also arranged in the needle cavity and rigidly fixed to the main body. In another embodiment, the stop element is comprised by the main body, for example it is represented by a step in the surface of the needle cavity.

[0019] These embodiments may, with advantage, allow for a particularly compact design and/or a particularly good reliability of the valve needle with respect to the relative axial movement of the first and second sections.

[0020] In one embodiment, the spring element is operable to press the second section against the valve seat when the valve assembly is in the closing configuration or in the first opening configuration.

[0021] In one embodiment, for transferring the valve assembly from the first opening configuration towards the second opening configuration, the main body of the valve needle is moveable in axial direction away from the valve seat. The valve needle may in particular be operable to take the second section with it by means of mechanical interaction of the second section with the stop element.

[0022] The valve assembly preferably has an armature for moving the valve needle. The fluid injection valve may have an actuator assembly for moving the armature. The actuator assembly is in particular an electromagnetic actuator assembly comprising a coil. In one embodiment, the armature is arranged in the valve cavity of the valve body and the coil surrounds the valve body. The armature is preferably arranged in the valve cavity of the valve body in axially moveable fashion.

[0023] The coil is, for example, operable to move the armature in axial direction away from the valve seat. The valve assembly may have an armature stop element which is operable to limit the axial displacement of the armature in the direction away from the valve seat. The armature stop element may be comprised by the valve body, for example. The valve assembly may be configured such that the armature abuts the armature stop element in the second opening configuration. In the first opening configuration, the armature is preferably positioned at a distance from the armature stop element.

[0024] The armature is operable to move the first section of the tip portion away from the valve seat. In particular, the armature takes the first section with it when it moves away from the valve seat for transferring the valve assembly from the closing configuration to the first opening configuration or from the first opening configuration to the second opening configuration. For example, the armature mechanically interacts with the shaft of the valve needle, which shaft is in particular fixedly coupled to the main body of the valve needle, for axially displacing the first section of the tip portion.

[0025] According to a further aspect, a method for operating the fluid injection valve is specified.

[0026] In one step of the method, a fluid quantity to be dispensed from the fluid injection valve during one injection event is determined. An operating mode of the injection valve is in particular selected in dependence of the determined fluid quantity. Expediently, the injection valve is operated in a first operating mode if the determined fluid quantity is less than a predetermined threshold and it is operated in a second operating mode if the determined fluid quantity exceeds the threshold.

[0027] According to the method, operating the fluid injection valve in the first operating mode for dispensing the determined fluid quantity comprises moving the first section of the tip portion of the valve needle away from the valve seat - in particular by means of mechanical interaction with the armature - so that the valve assembly is transferred from the closing configuration to the first opening configuration to release the determined fluid quantity trough the first set of orifices. In particular, the first set of orifices is unsealed by the displacement of the first section away from the valve seat. Subsequently, the first section of the tip portion is moved towards the valve seat for re-sealing the first set of orifices. However, during dispensing the determined fluid quantity trough the first set of orifices and in particular during axially moving the first section, the second section of the tip portion of the valve needle is retained in sealing contact with the second set of orifices when the fluid injection valve is operated in the first operating mode.

[0028] Operating the valve assembly in the second operating mode for dispensing the determined fluid quantity according to the method comprises moving the first section of the tip portion of the valve needle away from the valve seat and also moving the second section of the tip portion of the valve needle away from the valve seat - so that in particular the first set of orifices and the second set of orifices are unsealed - so that the valve assembly is transferred from the closing configuration to the second opening configuration for releasing the determined fluid quantity trough the first and second set of orifices. Subsequently, the first and second sections of the tip portion are moved towards the valve seat for re-sealing the first and second set of orifices.

[0029] In one embodiment of the method, transferring the valve assembly from the closing configuration to the second opening configuration in the second operating mode is effected in such fashion that the first section of the tip portion is moved away from the valve seat for transferring the valve assembly from the closing configuration to the first opening configuration to unseal the first set of orifices and, subsequently, the second section of the tip portion is moved away from the valve seat for unsealing the second set of orifices and transferring the valve assembly to the second opening configuration. Preferably, in this embodiment, the second section of the tip portion is moved towards the valve seat for re-sealing the second set of orifices and subsequently, the first section of the tip portion is moved relative to the second section toward from the valve seat re-sealing the first set of orifices.

[0030] In one development of this embodiment, the first section is axially displaced away from the valve seat by a first distance for bringing the valve assembly from the closing configuration to the first opening configuration. Subsequently, it is displaced further away from the valve seat in axial direction so that the stop element couples with the second section and takes the second section with it in the axial direction away from the valve seat until the second opening configuration is reached in which the first section is displaced by a second distance from the valve seat, the second distance being larger than the first distance. For example in this development, the maximum axial distance of the first section from the valve seat is larger in the second operating mode than in the first operating mode. In particular, the armature is always spaced apart from the armature stop element when the fluid injection valve is operated in the first operating mode.

[0031] In one embodiment of the method, the actuator assembly of the fluid injection valve is operated in such fashion that, in the first operating mode, the first section - and in particular the armature - start their movement towards the valve seat for returning to the closing configuration immediately after the movement away from the valve seat for reaching the first opening configuration is finished. In other words, the first section and the armature are not allowed to rest at the first distance. In particular, the acceleration of the first section is always non-zero at its transition through the reversal point at the first distance.

[0032] Further advantages, advantageous embodiments and developments of the valve needle, the valve assembly, the injection valve and the method will become apparent from the exemplary embodiments which are described below in association with schematic figures.

[0033] In the figures:

Figure 1

shows a schematic cross section of a valve assembly according to one exemplary embodiment in the closing configuration,

Figure 2

shows a schematic cross section of the valve assembly of figure 1 in the first opening configuration,

Figure 3

shows a schematic cross section of the valve assembly of figures one and two in the second opening configuration, and

Figure 4

shows a schematic cross section of an injection valve of comprising the valve assembly according to the embodiments of the figures 1, 2 and 3.

[0034] In the exemplary embodiments and figures, similar, identical or similarly acting elements are provided with the same reference symbols. The figures are not regarded to be true to scale. Rather, individual elements in the figures may be exaggerated in size for better representability and/or better understanding.

[0035] Figure 4 shows a schematic cross section of a fluid injection valve 3 comprising a valve assembly 2 which comprises a valve needle 1. The valve needle 1, the valve assembly 2 and the fluid injection valve 3 share a common longitudinal axis L.

[0036] Along the longitudinal axis L, the valve needle 1 extends from a shaft portion 19 to a tip portion 10. It is arranged in a valve cavity 45 of a valve body 4 of the valve assembly 2. The valve needle 1 is axially moveable in the valve cavity 45.

[0037] The valve body 4 extends from a fluid inlet end 31 to a fluid outlet end 32 where it has a valve seat which may be in one piece with the valve body 4, as in the exemplary embodiment of figure 4, but can also be a separate piece which is fixed to the valve body 4. The shaft portion 19 of the valve needle 1 is arranged adjacent to the fluid inlet end 31. The tip portion 10 of the valve needle 1 faces the valve seat 40 at the fluid outlet end 32. The valve body may comprise guide elements such as the lower guide elements 47 for guiding the valve needle 1 in the valve cavity 45. In this way, the risk of tilting of the valve needle 1 with respect to the longitudinal axis L is advantageously reduced.

[0038] The valve assembly further has an armature 7 for moving the valve needle 1. The fluid injection valve 3 has an actuator assembly for moving the armature 7. The actuator assembly, in the present embodiment, is an electromagnetic actuator assembly comprising a coil 8. The armature 7 is arranged in the valve cavity 45 and the coil 8 surrounds the valve body 4.

[0039] The armature 7 is arranged in the valve cavity 45 in axially moveable fashion. The coil 8 is operable to move the armature 7 in axial direction away from the valve seat 40. The armature 7 is operable to take the shaft portion 19 of the valve needle 1 with it when moving away from the valve seat 40 in axial direction, for example by means of a form fit connection between the armature 7 and the shaft portion 19.

[0040] The fluid injection valve 3 further comprises a calibration spring 9 for biasing the valve needle 1 in axial direction towards the valve seat 40. The calibration spring 9 is preloaded, for example by means of a calibration tube 49, so that it presses the tip portion 10 of the valve needle against the valve seat 40 when the actuator assembly is not energized. Further, the calibration tube 49, in the present embodiment, comprises an armature stop element 48 which limits the axial displacement of the armature 7 in the direction away from the valve seat 40. Alternatively, the armature stop element 48 may be separate from the calibration tube 49.

[0041] Figure 1 shows the tip portion 10 of the valve needle 1 in greater detail in a closing configuration of the valve assembly 2.

[0042] The tip portion 10 has a first section 11 and a second section 12. The first section 11 and the second section 12 are arranged concentrically with respect to each other. More specifically, the first section 11 of the tip portion 10 is comprised by the main body 15 of the valve needle 1 and extends circumferentially around the second portion 12 in a top view along the longitudinal axis L. The second section 12 is partially arranged in the needle cavity 17 and projects from the main body 15 with the first section 11 of the tip portion 10 in a first axial direction 51 along the longitudinal axis L towards the valve seat 40.

[0043] The main body 15 with the first section 11 of the tip portion 10 is pressed against the valve seat 40 by means of the preloaded calibration spring 9. The second section 12 of the tip portion 10 is axially moveable with respect to the first section 11 of the tip portion 10. However, it is biased in the first axial direction by means of a spring element 5 which is arranged in the needle cavity 17, so that it is also pressed against the valve seat 40. The spring element 5 may, for example, be preloaded by means of a washer 21 which is arranged in needle cavity 17 and rigidly coupled to the latter, for example by means of friction fit.

[0044] The valve seat 40 has a first set of orifices 41 and a second set of orifices 42. Each of the orifices is provided for enabling fluid flow from the valve cavity 45 to the outside of the valve assembly 2. For example, the second set of orifices 42 is arranged, in top view along the longitudinal axis L, within an imaginary ring shaped contour. The first set of orifices 41 may, for example, be also arranged in top view along the longitudinal axis L within another imaginary ring shaped contour. The first section 11 of the tip portion 10 is arranged to seal the first set of orifices 41 to prevent fluid flow through the first set of orifices 41. The second section 12 of the tip portion 10 is arranged to seal the second set of orifices 42 for preventing fluid flow through the second orifices 42.

[0045] The valve assembly 2 can be brought from the closing configuration to a first opening configuration. For transferring the valve assembly 2 from the closing configuration to the first opening configuration, the first section 11 of the tip portion 10 is moved in a second direction 52 along the longitudinal axis L, i.e. in a direction away from the valve seat 40. The axial displacement of the first section is in particular effected by activating the actuator assembly so that, in the present embodiment, the armature 7 moves the main body 15 - which comprises the first section 11 of the tip potion 10 - away from the valve seat 40. By means of the axial displacement of the first section 11, the first set of orifices 41 is unsealed, so that fluid may flow from the valve cavity 45 trough the first set of orifices 41 to be dispensed from the valve assembly 2.

[0046] When the main body 15 is moved for displacing the first section 11 of the tip portion 10 away from the valve seat 40 for transferring the valve assembly 2 from the closing configuration to the first opening configuration, the first section 11 moves in the second axial direction 52 with respect to the valve body 4 including the valve seat 40 and with respect to the second section 12 of the tip portion 10 of the valve needle 1.

[0047] The washer 21, which preloads the spring element 5 is also moved away from the valve seat 40 together with the main body 15. However, the preload of spring element 5 is set such, that the spring element 5 is operable to press the second section 12 onto the valve seat also in the first opening configuration of the valve assembly. In this way, the second set of orifices 42 remains sealed when the valve assembly 2 is in the first opening configuration.

[0048] By moving the main body 15 of the valve needle 1 further into the second axial direction 52, the valve assembly 2 can be brought from the first opening configuration to a second opening configuration, which is shown in the schematic cross section of figure 3.

[0049] The main body 15 has a stop element 6 which limits the axial displacement of the second section 12 with respect to the first section 11 of the tip portion 10 of the valve needle 1. When the main body 15 with the first section 11 is moved further in the second axial direction 52 away from the valve seat 40, the main body 15 takes the second section 12 with it by means of mechanical of interaction between the stop element 6 and the second section 12. For example, the stop element 6 is a step of the surface of the needle cavity 17 and the second section 12 has a collar which overlaps the step in top view along the longitudinal axis L. In this way, the second section 12 is moved away from the valve seat 40.

[0050] In the second opening configuration, both the first section 11 and the second section 12 of the tip portion 10 of the valve needle 1 are spaced apart from the valve seat 40, so that the first set of orifices 41 and the second set of orifices 42 are both unsealed. Thus, in the second opening configuration, fluid may flow from the valve cavity 45 through the first orifices 41 and trough the second orifices 42 the outside of the valve assembly 2.

[0051] In this way, the fluid injection valve 3 is operable to inject particularly small doses of fluid with a particularly high precision and repeatability when it is operated in a so called "ballistic" operation mode in which the actuator assembly is de-energized before the armature 7 has reached the armature stop element 48 and before valve needle 1 has reached its largest possible axial displacement. In particular, the fluid injection valve 3 may be operated in a first operating mode in which the valve assembly 3 is only switched between the closing configuration and the first opening configuration. The maximum axial displacement of the first section 11 of the tip portion 10 in the first operating mode is in particular smaller than in a second operating mode, where the valve assembly 2 is switched between the closing configuration and the second opening configuration. In this way, for example by switching between the first and the second operating modes, the injection valve 3 may have a large working range with respect to fluid doses to be dispensed during one injection event. At the same time, dosage of small fluid amounts is particularly precise in the first operating mode. The first operating mode also allows to dispense particularly small fluid amounts of fluid per injection event.

[0052] In a method for operating the fluid injection valve 3, a fluid quantity to be dispensed from the injection valve 3 during one injection event is determined. The operating mode of the fluid injection valve 3 is selected in dependence on the determined fluid quantity. If the determined fluid quantity is less than a predetermined threshold, the fluid injection valve 3 is operated in the first operating mode. If the determined fluid quantity exceeds the threshold, the injection valve 3 is operated in the second operating mode.

[0053] Operating the fluid injection valve 3 in the first operating mode for dispensing the determined fluid quantity comprises in particular moving the first section 11 of the tip portion 10 of the valve needle 1 away from the valve seat 40 so that the valve assembly 2 is transferred from the closing configuration to the first opening configuration for releasing the determined fluid quantity through the first set of orifices 41. Subsequently, the first section 11 of the tip portion 10 is moved towards the valve seat 40 again for re-sealing the first set of orifices 41. Preferably, the movement of the first section 11 towards the valve seat 40 is initiated immediately after the movement of the first section 11 away from the valve seat 40 has finished, so that the main body 15 of the valve needle 1 and the armature 7 are not allowed to come to rest before the first orifices 41 are re-sealed and so that the armature 7 does not reach the armature stop element 48 in the first operating mode, but is always at a distance from the armature stop element 48. The second section 12 of the tip portion 10 of the valve needle 1 remains in sealing contact with the second set of orifices 42 while the first set of orifices 41 is unsealed.

[0054] Operating the valve assembly 2 in the second operating mode for dispensing the determined fluid quantity comprises moving the first section 11 of the tip portion 10 of the valve needle 1 away from the valve seat 40 so that the valve assembly 2 is transferred from the closing configuration to the first opening configuration for un-sealing the first set of orifices 41. When the valve assembly 2 has reached the first opening configuration, the movement of the main body 15 away from the valve seat 40 in the second axial direction 52 is continued, preferably without a stop, so that the second section 12 is brought into contact with the stop element 6 for moving the second section 12 away from the valve seat 40, as well, so that the valve assembly 2 is transferred from the first opening configuration to the second opening configuration. In this way, the determined fluid quantity is released through both the first and second set of orifices 41, 42.

[0055] The valve assembly may be allowed to come to a rest in the second opening configuration in one development of the method. For example, the armature 7 abuts the armature stop element 48 in the second opening configuration.

[0056] Subsequently, the coil 8 is de-energized so that the calibration spring 9 moves the main body 15 with the first section 11 - and, by means of mechanical interaction via the washer 21 and the spring element 5, also the second section 12 - towards the valve seat 40. The main body 15 also takes the armature 7 with it in the direction 51 towards the valve seat 40. When the second section 12 reaches the valve seat 40, the second set of orifices 42 is re-sealed and the second section 12 decouples from the stop element 6 so that the main body 15 moves further towards the valve seat 40 until the first section 11 also contacts the valve seat 40 to seal the first set of orifices 41 and the valve assembly 2 is in the closing configuration, again.

[0057] The invention is not limited to specific embodiments by the description on basis of the above exemplary embodiments. Rather, it comprises any combination of elements of different embodiments and developments. Moreover, the invention comprises any combination of claims and any combination of features disclosed by the claims.

Claims

1. Valve assembly (2) for a fluid injection valve (3) having a longitudinal axis (L) and comprising a valve body (4) having a valve cavity (45) and a valve seat (40), a valve needle (1) and an armature (7), the valve needle (1) and the armature (7) being arranged in the valve cavity (45) in axially moveable fashion, wherein
the valve seat (40) has a first set of orifices (41) and a second set of orifices (42),
the valve needle (1) comprises a tip portion (10), the tip portion (10) has a first section (11) and a second section (12), the first section (11) being operable to seal the first set of orifices (41), the second section (12) being operable to seal the second set of orifices (42), and the second section (12) being axially movable with respect to the first section (11),
and the armature (7) being operable to interact mechanically with the valve needle (1) for axially displacing the first section (11) away from the valve seat (40).

2. The valve assembly (2) of claim 1, wherein the valve needle (1) is axially movably arranged in the valve cavity (45) in such fashion that

- the valve assembly (2) has a closing configuration in which the first section (11) of the tip portion (10) is operable to seal the first set of orifices (41) and the second section (12) of the tip portion (10) is operable to seal the second set of orifices (42) for preventing fluid flow from the valve cavity (45) through the first and second sets of orifices (41, 42),

- the valve assembly (2) is transferable from the closing configuration to a first opening configuration by means of an axial displacement of the first section (11) relative to the valve body (4) and the second section (12) in a direction away from the valve seat (40), in which first opening configuration the valve assembly (2) is operable to release fluid from the valve cavity (45) through the first set of orifices (41) while the second section (12) is operable to seal the second set of orifices (42), and

- the valve assembly (2) is transferable from the first opening configuration to a second opening configuration by means of an axial displacement of the second section (12) relative to the valve body (4) in a direction away from the valve seat (40), in which second opening configuration the valve assembly (2) is operable to release fluid through the first set of orifices (41) and the second set of orifices (42).

3. The valve assembly (2) of one of the preceding claims,
wherein the valve needle (1) additionally comprises a spring element (5) which is operable to bias the second section (12) of the tip portion (10) in a first axial direction (51) and a stop element (6) which is operable to limit axial displacement of the second section (12) in the first axial direction (51) with respect to the first section (11) of the tip portion (10).

4. The valve assembly (2) according to claim 3 in dependence on claim 2, wherein the spring element (5) is operable to press the second section (12) against the valve seat (40) when the valve assembly (2) is in the closing configuration or in the first opening configuration.

5. The valve assembly (2) of one of the preceding claims comprising a main body (15) with a needle cavity (17), wherein the first section (11) of the tip portion (10) is in one piece with the main body (15) and the second section (12) of the tip portion (10) is received in the needle cavity (17).

6. The valve assembly (2) of claim 5 in dependence on claim 4, wherein the spring element (5) is arranged in the needle cavity (17) and the stop element (6) is comprised by the main body (15).

7. The valve assembly (2) according to claim 6, wherein, for transferring the valve assembly (2) from the first opening configuration towards the second opening configuration, the main body (15) of the valve needle (1) is movable in an axial direction away from the valve seat (40) and is operable to take the second section (12) with it by means of mechanical interaction of the second section (12) with the stop element (6).

8. Fluid injection valve (3) comprising the valve assembly (2) according to one of the preceding claims and an electromagnetic actuator assembly having a coil (8) for moving the armature (7).

9. Method for operating a fluid injection valve (3) comprising the valve assembly of claim 2 or of any one of claims 3 to 7 in direct or indirect dependence on claim 2, the method comprising the following steps:

- determining a fluid quantity to be dispensed from the injection valve (3) during one injection event and

- operating the injection valve (3) in a first operating mode if the determined fluid quantity is less than a predetermined threshold and in a second operating mode if the determined fluid quantity exceeds the threshold, wherein
operating the fluid injection valve (3) in the first operating mode for dispensing the determined fluid quantity comprises

- moving the first section (11) of the tip portion (10) of the valve needle (1) away from the valve seat (40) so that the valve assembly (2) is transferred from the closing configuration to the first opening configuration for releasing the determined fluid quantity through the first set of orifices (41),

- subsequently moving the first section (11) of the tip portion (10) towards the valve seat (40) for re-sealing the first set of orifices (41), and

- retaining the second section (12) of the tip portion (10) of the valve needle (1) in sealing contact with the second set of orifices (42) during dispensing the determined fluid quantity
and operating the valve assembly in the second operating mode for dispensing the determined fluid quantity comprises

- moving the first section (11) of the tip portion (10) of the valve needle (1) away from the valve seat (40) and moving the second section (12) of the tip portion (10) of the valve needle (1) away from the valve seat (40) so that the valve assembly (2) is transferred from the closing configuration to the second opening configuration for releasing the determined fluid quantity through both the first and second set of orifices (41, 42),

- subsequently moving the first and second sections (11, 12) of the tip portion (10) towards the valve seat (40) for re-sealing the first and second set of orifices (41, 42).

10. The method of claim 9, wherein a maximum axial displacement of the first section (11) away from the valve seat (40) is larger in the second operating mode than in the first operating mode.

11. The method of claim 9 or 10, wherein

- the valve assembly (2) comprises an armature stop element (48) which is operable to limit the axial displacement of the armature (7) in a direction away from the valve seat (40)

- the armature (7) is always spaced apart from the armature stop element (48) when the fluid injection valve (3) is operated in the first operating mode and

- the armature (7) abuts the armature stop element (48) while the valve assembly (2) is in the second opening configuration.

12. The method of any one of claims 9 to 11, wherein the fluid injection valve (3) comprises an electromagnetic actuator assembly and the actuator assembly is operated in such fashion that, in the first operating mode, the first section (11) and the armature (7) start their axial movement towards the valve seat (40) for returning to the closing configuration immediately after the axial movement away from the valve seat (40) for reaching the first opening configuration is finished.

13. The method of any one of claims 9 to 12, wherein operating the fluid injection valve (3) in the second operating mode for dispensing the determined fluid quantity comprises moving the first section (11) of the tip portion (10) away from the valve seat (40) so that the valve assembly (2) is transferred from the closing configuration to the first opening configuration for un-sealing the first set of orifices (41) and subsequently moving the second section (12) of the tip portion (10) away from the valve seat (40) for un-sealing the second set of orifices (42).

Drawing