Electromagnetic fuel injector with two independent coils and associated control method

Abstract

An electromagnetic fuel injector (1) has: a tubular support body (4); a spray nozzle (3) arranged at an end of the support body (4); an injection valve (7) coupled to the injection nozzle (3); a plunger (8) which is movable in order to adjust the flow of fuel through the injection nozzle (3) between a closed position and an open position of the injection valve (7); an electromagnetic actuator (6) provided with a primary electromagnet (11) configured to apply a force to the plunger (8) when activated, the force urging the plunger (8) towards the open position of the injection valve (7), and a secondary electromagnet (12) configured to apply a force to the plunger (8) when activated, the force urging the plunger (8) towards the closed position of the injection valve (7); and a closing spring (10) configured to urge the plunger (8) toward the closed position of the injection valve (7).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims the priority of Italian patent application No. 102023000014394 filed on July 10, 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to electromagnetic fuel injectors and associated control methods.

[0004] The present invention is advantageously applied to electromagnetic hydrogen injectors, and without loss of generality, the following discussion will explicitly refer to electromagnetic hydrogen injectors. Background Art

[0005] Typically, an electromagnetic fuel injector, such as described in patent application EP1611384A2, comprises a cylindrical tubular support body provided with a central supply channel, which serves as a fuel conduit and terminates in an injection nozzle regulated by an injection valve controlled by an electromagnetic actuator. The injection valve is provided with a plunger which moves between a closed position and an open position of the injection nozzle by the action of the electromagnetic actuator against the action of a closing spring which pushes the plunger towards the closed position. The plunger terminates in a gate head adapted to sealingly abut against a valve seat of the injection valve.

[0006] The electromagnetic actuator comprises (at least one) coil, which is arranged externally around a support body and is located in a fixed position; a movable armature made of ferromagnetic material, which is rigidly connected to a plunger and movably mounted in the support body; and a fixed armature (or bottom) made of ferromagnetic material, which is arranged in the support body in the area of ​​the coil and is suitable for magnetically attracting the armature when the coil is energized.

[0007] When liquid fuel is injected, the presence of liquid fuel inside the support body constitutes a relevant obstacle to the movement of the movable armature, in effect forming a hydraulic damper that limits the speed of movement of the movable armature; however, when gaseous fuel is injected (in particular when hydrogen is injected, which is a very light gas), the presence of gaseous fuel inside the support body does not constitute a relevant obstacle to the movement of the movable armature, so that the movable armature moves at a high speed and violently impacts the armature at the end of the opening movement. This violent impact of the movable armature against the armature at the end of the opening movement causes high noise levels and accelerated degradation (wear); moreover, this violent impact of the movable armature against the armature at the end of the opening movement also causes a relevant rebound phenomenon, which introduces a certain amount of randomness in the amount of injected fuel.

[0008] At this point it is important to observe that hydrogen has a reduced density (having a very simple molecule consisting of only two hydrogen atoms), so in order to be able to inject a sufficient amount (mass) of hydrogen into the combustion chamber, it is necessary to inject a correspondingly relevant volume of hydrogen, which requires, among other things, a large area of ​​the passage area of ​​the hydrogen through the injection valve (i.e. the opening through which the hydrogen must pass in order to leave the hydrogen injector must be large). In order for the passage area of ​​the hydrogen through the injection valve to have a large area, it is necessary for the plunger (and therefore the movable armature) to have a long movement between the closed position and the open position, which further increases the impact speed of the movable armature on the armature at the end of the opening movement.

[0009] In order to limit the impact speed of the movable armature against the armature at the end of the opening movement, a specific curve of the current passed through the coil of the electromagnetic actuator is currently used, and when the movable armature is close to the armature, the specific curve of the current should be able to reduce the magnetic force that attracts the movable armature towards the armature; however, when the movable armature is close to the armature, the control of the magnetic force that attracts the movable armature towards the armature is extremely complex and relatively imprecise, because in this position, the magnetic force that attracts the movable armature towards the armature is very non-linear (that is, when the air gap between the movable armature and the armature becomes very small, the magnetic force increases exponentially).

[0010] Patent application DE10101060A1 describes a fuel injector for a diesel engine, comprising: a throttle needle for locking an injection channel, an armature mounted on the needle, an electric opening solenoid for applying an induced magnetic field to the armature (the induced magnetic field moves the armature toward the open position of the injection channel), and an electric closing solenoid for applying an induced magnetic field to the armature (the induced magnetic field moves the armature toward the closed position of the injection channel). Summary of the invention

[0011] The object of the present invention is to produce an electromagnetic fuel injector which does not have the above-mentioned disadvantages, ie has a low noise level and moderate degradation (wear), while being easy and inexpensive to produce.

[0012] According to the present invention, as claimed in the accompanying claims, there is provided an electromagnetic fuel injector and an associated control method.

[0013] The claims describe preferred embodiments of the invention and are an integral part of the present description. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will now be described with reference to the accompanying drawings, which illustrate non-limiting example embodiments of the present invention, in which:

[0015] Figure 1 is a longitudinal cross-sectional view of a portion of a fuel injector manufactured in accordance with the present invention;

[0016] Figure 2 yes Figure 1 an enlarged view of a detail; and

[0017] Figure 3 is a graph showing the opening and subsequent closing of the injection valve. Figure 1 Diagram of the time evolution of the position of the two electromagnets of the fuel injector's activated and movable components. DETAILED DESCRIPTION

[0018] exist Figure 1 1 , reference numeral 1 generally denotes a gaseous (in particular hydrogen) electromagnetic fuel injector having cylindrical symmetry about a longitudinal axis 2 and being adapted to be controlled for injecting hydrogen through an injection nozzle 3, the hydrogen flowing directly into a combustion chamber of a cylinder of an internal combustion engine (not shown).

[0019] The electromagnetic injector 1 comprises a support body 4 having a cylindrical tubular shape with a variable section along the longitudinal axis 2 and having a supply channel 5 extending along the entire length of the support body 4 for supplying hydrogen under pressure towards the injection nozzle 3 .

[0020] The support body 4 houses an electromagnetic actuator 6 and an injection valve 7 ; in use, the injection valve 7 is operated by the electromagnetic actuator 6 for regulating the flow of hydrogen through the injection nozzle 3 , the hydrogen flow being obtained in the region of the injection valve 7 .

[0021] The electromagnetic actuator 6 is configured to move a movable assembly axially (i.e. along the longitudinal axis 2), the movable assembly being provided with a plunger 8, which ends with a gate 9. The gate 9 cooperates with the valve seat of the injection valve 7 for regulating the flow of hydrogen through the injection nozzle 3. In other words, the support body 4 ends with (at least one) through-going opening, the valve seat is defined in the through-going opening, and the through-going opening is engaged with the gate 9. In particular, the electromagnetic actuator 6 is configured to move the gate 9 between a closed position and an open position of the injection valve 7. In addition, the electromagnetic actuator 6 is coupled to a closing spring 10, which keeps the electromagnetic injector 1 normally closed, that is, the closing spring 10 pushes the gate 9 to the closed position of the injection valve 7. In other words, the injection valve 7 is usually closed under the action of the closing spring 10, which pushes the plunger 8 into the closed position, in which the gate 9 of the plunger 8 is pressed against the valve seat of the injection valve 7.

[0022] In the embodiment shown in the drawings, the injection valve 7 opens with an axial movement toward the inside, and preferably, the gate 9 has a spherical shape; according to a different embodiment not shown, the injection valve 7 opens with an axial movement toward the outside, and preferably, the gate 9 has a truncated cone shape.

[0023] according to Figure 2 As better shown in FIG. 1 , the electromagnetic actuator 6 comprises a main electromagnet 11 and a secondary electromagnet 12, which are controlled in an independent manner, the main electromagnet 11 being configured to exert a force on the plunger 8 (when it is activated) to open the injection valve 7 (thus opposing the elastic force generated by the closing spring 10), while the secondary electromagnet 12 is configured to exert a force on the plunger 8 (when it is activated) to close the injection valve 7 (thus consistent with the elastic force generated by the closing spring 10). In other words, the two electromagnets 11 and 12 are configured to exert forces on the plunger 8 that are opposite to each other.

[0024] The main electromagnet 11 comprises a main coil 13 housed outside relative to the support body 4 and a main armature 14 (magnetic pole or bottom or magnetic expansion) made of ferromagnetic material, the main armature 14 being housed inside the support body 4, in a fixed position in the area of ​​the main coil 13 and having a central hole 15 allowing the fuel to flow to the injection nozzle 3; that is, the armature 14 is inserted into the support body 4 and is integral with the support body 4 (usually it is welded to the support body 4).

[0025] The secondary electromagnet 12 comprises a secondary coil 16 housed outside relative to the support body 4 and a secondary armature 17 (magnetic pole or bottom or magnetic expansion) made of ferromagnetic material, the secondary armature 17 being housed inside the support body 4, in a fixed position in the region of the secondary coil 16, and having a central hole 17 for allowing the fuel to flow to the injection nozzle 3; that is, the armature 17 is inserted into the support body 4 and is integral with the support body 4 (the armature 17 is welded to the support body 4).

[0026] In the embodiment shown in the figures, a single armature 19 is provided, which is integral with the plunger 8 (i.e., is part of a movable assembly), is arranged between the two armatures 14 and 17, and is shared by the two electromagnets 11 and 12; i.e., the armature 19 is magnetically coupled to the primary coil 13, because it is traversed by the magnetic current generated by the primary coil 13, and the armature 19 is also magnetically coupled to the secondary coil 17, because it is traversed by the magnetic current generated by the secondary coil 17. That is, by energizing the primary coil 13, the magnetic field generated attracts the armature 19 towards the primary armature 14, and in a similar manner, by energizing the secondary coil 16, the magnetic field generated attracts the armature 19 towards the secondary armature 17. According to a different embodiment, not shown, each electromagnet 11 or 12 comprises its own armature 19, so that two armatures 19 are provided, which are separate and independent from each other and are both integral with the plunger 8 (i.e., are part of a movable assembly); in this embodiment, each electromagnet 11 or 12 is configured to magnetically attract only the corresponding armature 19.

[0027] The electromagnetic injector 1 includes (is connected to) a control unit 20 (in Figure 1), the control unit 20 electrically powers the two coils 13 and 16 of the two electromagnets 11 and 12 independently of each other; that is, the control unit 20 drives (electrically powers) the main coil 13 of the main electromagnet 11 independently of the secondary coil 16 of the secondary electromagnet 12. In particular, the control unit 20 includes a controller 21 and a controller 22, the controller 21 is only connected to the main coil 13 for electrically powering the main coil 13, and the controller 22 is only connected to the secondary coil 16 for electrically powering the secondary coil 16.

[0028] In other words, the electromagnets 11 and 12 are independently controlled, ie the two coils 13 and 16 are not connected to each other in series or in parallel, but are energized by two different controllers 21 and 22 so as to be passed different and distinct currents (as better explained below).

[0029] In use, when the electromagnets 11 and 12 are de-energized, the armature 19 is not subjected to any force of magnetic origin and is therefore only subjected to the elastic force generated by the closing spring 10, which pushes the armature 19 together with the plunger 8 to the closed position (i.e. downward), and in this case, the injection valve 7 is closed; preferably, in the closed position, the armature 19 is close to (approaching) the secondary armature 17, but not in contact with the secondary armature 17, i.e., there is free space between the armature 19 and the secondary armature 17 (therefore, the "stop" of the closed position is established by the contact of the gate 9 against the valve seat of the injection valve 7 rather than by the contact of the armature 19 against the secondary armature 17).

[0030] In use, in order to open the injection valve 7, the main electromagnet 11 is activated (i.e. the main coil 13 is energized) so that the main electromagnet 11 generates a magnetic force that attracts the armature 19 towards the main armature 14 (i.e. towards the open position), overcoming the elastic force of the closing spring 10; thus, the armature 19 moves towards the main armature 14 (i.e. towards the open position), determining the gradual opening of the injection valve 7. When the armature 19 approaches the main armature 14 (i.e. approaches the open position), the secondary electromagnet 12 is also activated (i.e. the secondary coil 16 is energized) so that the secondary electromagnet 12 generates a magnetic force that attracts the armature 19 towards the secondary armature 17, thereby slowing down the movement of the armature 19 towards the main armature 14 (i.e. towards the open position). It is important to observe that the magnetic force generated by the secondary electromagnet 12 cannot (i.e. is not strong enough) stop or reverse the movement of the armature 19 towards the main armature 14 (i.e. towards the open position), and only has the effect of slowing down (braking) the movement of the armature 19 towards the main armature 14 (i.e. towards the open position). Therefore, at the end of the opening step, the armature 19 ends its movement against the main armature 14 (the "stop" of the open position is established by the contact of the armature 19 against the main armature 14), and the armature 19 hits the main armature 14 at a relatively moderate speed through the deceleration (braking) action applied by the secondary electromagnet 12 (more generally, the "stop" of the open position is established by the contact of an element of the movable component against a fixed element integral with the support body 4).

[0031] As soon as the armature 19 comes into contact with the main armature 14, in order to keep the injection valve 7 open, only the main electromagnet 11 remains activated (usually by energizing the main coil 13 with a current of lesser intensity, since the reduced magnetic force is sufficient to maintain the open position), while the secondary electromagnet 12 is switched off (since its function is useless when the armature 19 is stationary and in contact with the main armature 14).

[0032] In use, to close the injection valve 7, the main electromagnet 11 is closed, so that the armature 19, no longer subject to any force having a magnetic source, is pushed towards the closed position (i.e. downwards) by the elastic force generated by the closing spring 10, so that the armature 19 is separated from the main armature 14 and moves towards the secondary armature 17 (the armature 19 will never reach, that is, never reach to contact with the secondary armature 17, because the "stop" of the closed position is established by the contact of the gate 9 against the valve seat of the injection valve 7 before the contact of the armature 19 against the secondary armature 17 occurs). Usually, during the entire closing step, the secondary electromagnet 12 remains closed, because the elastic force generated by the closing spring 10 is sufficient for the rapid closing of the injection valve 7; according to an alternative embodiment, at least in the initial part of the closing step, the secondary electromagnet 12 can be activated (by energizing the secondary coil 16) for increasing the speed of the armature 19 towards the main armature 14, thereby accelerating the closing step.

[0033] When the gate 9 approaches the valve seat of the injection valve 7, the main electromagnet 11 is briefly activated (reactivated) (i.e. the main coil 13 is energized) so that the main electromagnet 11 generates a magnetic force that attracts the armature 19 towards the main armature 14, thereby slowing down the movement of the armature 19 towards the closed position. It is important to observe that the magnetic force generated by the main electromagnet 11 at the end of the closing step is not able (i.e. not strong enough) to stop or reverse the movement of the armature 19 towards the closed position, and only has the effect of slowing down (braking) the movement of the armature 19 towards the closed position. Therefore, at the end of the closing step, when the gate 9 hits the valve seat of the injection valve 7 (the "stop" of the closed position is established by the contact of the gate 9 against the valve seat of the injection valve 7), the armature 19 ends its movement and, through the deceleration (braking) effect applied by the main electromagnet 11, the gate hits the valve seat of the injection valve 7 at a relatively moderate speed.

[0034] Figure 3 The above description is schematically shown in FIG. Figure 3 The upper area of ​​shows the temporal trend of the position of the movable components (i.e. the armature 19, the plunger 8 and the gate 9) which move between the closed position (“CLOSED”) and the open position (“OPEN”), Figure 3 The middle area of ​​​​the diagram shows the time trend of the state of the main electromagnet 11, which changes between a deactivated state ("off") and an activated state ("on"), and Figure 3 The lower region of shows the time trend of the state of the secondary electromagnet 12 , which changes between a deactivated state (“off”) and an activated state (“on”).

[0035] according to Figure 3 As shown, before time t1, both electromagnets 11 and 12 are turned off, so that the armature 19 (i.e., the movable component) is still in the closed position. At time t1, the main electromagnet 11 is activated, and (under the action of electromagnetic inertia and mechanical inertia) at time t2, the main electromagnet 11 begins to move the armature 19 from the closed position to the open position, reaching the open position at time t5. Between time t3 and time t4, the secondary electromagnet 12 is also activated to slow down (brake) the armature 19 approaching the open position (i.e., just before the armature 19 hits the main armature 14); the action of the secondary electromagnet 12 is not immediately affected by the electromagnetic inertia and mechanical inertia, and the secondary electromagnet 12 is deactivated before the armature 19 reaches the open position in order to take into account the effects of electromagnetic inertia and mechanical inertia. At time t6, the main electromagnet 11 is deactivated, so that (through the action of electromagnetic inertia and mechanical inertia) at time t7, the action of the closing spring 10 pushes the armature 19 towards the open position at time t 10Between time t8 and time t9, the main electromagnet 11 is activated to slow down (brake) the armature 19 to the open position (i.e., just before the gate 9 hits the valve seat of the injection valve 7); the action of the main electromagnet 11 is not immediately affected by electromagnetic inertia and mechanical inertia, and the main electromagnet 11 is deactivated before the armature 19 reaches the closed position in order to take into account the influence of electromagnetic inertia and mechanical inertia.

[0036] According to a preferred embodiment, the electromagnets 11 and 12 are open-loop controlled so that a predetermined current trend (curve) circulates in the corresponding coils 13 and 16; a self-calibration logic can be provided, which estimates the actual opening and / or closing time of the injection valve 7, and based on the actual opening and / or closing time of the injection valve 7, the self-calibration logic can provide (if necessary) a correction to the predetermined current trend (curve).

[0037] According to a possible embodiment, during the entire closing step, the main electromagnet 11 remains closed (especially if the secondary electromagnet 12 also remains closed).

[0038] According to an alternative embodiment, when the armature 19 approaches the “stop” of the closed position (established by the contact of the gate 9 against the valve seat of the injection valve 7), the main electromagnet 11 is activated (i.e. the main coil 13 is energized) so that the main electromagnet 11 generates a magnetic force that attracts the armature 19 towards the main armature 14, thereby slowing down the movement of the armature 19 towards the main armature 14. It is important to observe that during the closing step, the magnetic force generated by the main electromagnet 11 is not able (i.e. not strong enough) to stop or reverse the movement of the armature 19 towards the secondary armature 17, and only has the effect of slowing down (braking) the movement of the armature 19 towards the secondary armature 17. Therefore, at the end of the closing step, when the gate 9 reaches contact (impact) with the valve seat of the injection valve 7 (i.e. reaches the “stop” of the closed position), the armature 19 ends its movement, the contact (impact) occurring at a relatively moderate speed under the influence of the deceleration (braking) effect exerted by the main electromagnet 11.

[0039] According to a preferred embodiment, the two coils 13 and 16 are different from each other because they must generate magnetic forces of different strengths under different conditions: the primary coil 13 (in combination with the primary armature 14) must generate a magnetic force sufficient to overcome the elastic force of the closing spring 10 and attract the armature 19 toward the primary armature 14, while the secondary coil 16 (in combination with the secondary armature 17) must slow down (not stop) the end portion of the movement of the armature 19 toward the primary armature 14. Therefore, the two coils 13 and 16 are usually different from each other in the number of turns and therefore also in shape and / or size.

[0040] Summarizing what has been described above, the movable assembly (thus the plunger 8 carrying the shutter 9) is subjected (in addition to the elastic force generated by the closing spring 10) to two mutually independent magnetic forces, since they are generated by two electromagnets 11 and 12 driven independently of each other.

[0041] In the preferred embodiment described above, the electromagnetic injector 1 is configured to inject hydrogen, but alternatively, the electromagnetic injector 1 can be configured to inject any other type of gaseous fuel, such as methane, or can be configured to also inject liquid fuel or water (usually when a high injection flow rate is required, which particularly requires a long movement of the plunger 8).

[0042] The embodiments described herein may be combined with each other without departing from the scope of protection of the present innovation.

[0043] The electromagnetic fuel injector 1 described above has many advantages.

[0044] Firstly, the electromagnetic fuel injector 1 described above has a low noise level and moderate degradation (wear) due to the fact that the impact of the armature 19 on the main armature 14 (at the end of the opening step) and the impact of the gate 9 on the valve seat of the injection valve 7 (at the end of the closing step) occur at a relatively reduced impact speed. In addition, in this way, the rebound phenomenon, which introduces a certain amount of randomness in the injected fuel quantity, is also reduced.

[0045] Furthermore, the electromagnetic fuel injector 1 described above is simple and inexpensive to produce, since it has few structural differences relative to similar known electromagnetic injectors which facilitate manufacture.

[0046] LIST OF REFERENCE NUMBERS FOR THE DRAWINGS

[0047] 1 Fuel Injector

[0048] 2 Longitudinal axis

[0049] 3 spray nozzles

[0050] 4 Support body

[0051] 5 Supply channels

[0052] 6 Electromagnetic actuator

[0053] 7 Injection valve

[0054] 8 Plunger

[0055] 9 Gates

[0056] 10 Closing spring

[0057] 11 Main solenoid

[0058] 12 Secondary electromagnet

[0059] 13 Main coil

[0060] 14 Main armature

[0061] 15 center hole

[0062] 16 Secondary coil

[0063] 17 Secondary Armature

[0064] 18 center hole

[0065] 19 Armature

[0066] 20Control Unit

[0067] 21 Controller

[0068] 22 Controller

Claims

1. An electromagnetic fuel injector (1), comprising: A tubular support body (4); a spray nozzle (3) arranged at the end of the support body (4); an injection valve (7) connected to the injection nozzle (3); a plunger (8) movable to regulate the flow of fuel through the injection nozzle (3) between a closed position and an open position of the injection valve (7); An electromagnetic actuator (6), the electromagnetic actuator being provided with a main electromagnet (11) and a secondary electromagnet (12), the main electromagnet being configured to apply a force to the plunger (8) when it is activated, the force pushing the plunger (8) toward the open position of the injection valve (7), and the secondary electromagnet being configured to apply a force to the plunger (8) when it is activated, the force pushing the plunger (8) toward the closed position of the injection valve (7); a closing spring (10) configured to push the plunger (8) toward a closed position of the injection valve (7); and A control unit (20) configured to open the injection valve (7) to activate the main electromagnet (11) so that the main electromagnet (11) generates a magnetic force that moves the plunger (8) toward the open position, overcoming the elastic force of the closing spring (10); The electromagnetic injector (1) is characterized in that the control unit (20) is configured to also activate the secondary electromagnet (12) during the opening of the injection valve (7) and when the plunger (8) is close to the open position, so that the secondary electromagnet (12) generates a magnetic force to slow down the movement of the plunger (8) towards the open position.

2. The electromagnetic injector (1) according to claim 1, wherein: The electromagnetic actuator (6) comprises a single armature (19) which is movable, integral with the plunger (8) and shared by two electromagnets (11, 12) because the armature is acted upon by magnetic forces generated by the two electromagnets (11, 12).

3. The electromagnetic injector (1) according to claim 2, wherein: The main electromagnet (11) comprises a main armature (14) which is integral with the support body (4) and a main coil (13) which is arranged in the region of the main armature (14); The secondary electromagnet (12) comprises a secondary armature (17) which is integral with the support body (4) and a secondary coil (16) which is arranged in the region of the secondary armature (17); and The armature (19) is arranged between the primary armature (14) and the secondary armature (17).

4. The electromagnetic injector (1) according to claim 3, wherein: The closed position of the injection valve (7) is determined by the contact of the gate (9) of the plunger (8) against the valve seat of the injection valve (7); and The open position of the injection valve (7) is determined by the contact of the movable armature (19) against the main armature (14).

5. The electromagnetic injector (1) according to claim 3, wherein: The two coils (13, 16) of the two electromagnets (11, 12) are not connected in series or in parallel with each other; and The control unit (20) is configured to supply power to the two coils (13, 16) of the two electromagnets (11, 12) independently of each other.

6. The electromagnetic injector (1) according to claim 3, wherein: The control unit (20) is configured to open the injection valve (7) so as to: activating the main electromagnet (11) so that the main electromagnet (11) generates a magnetic force that attracts the armature (19) toward the main armature (14), overcoming the elastic force of the closing spring (10), thereby moving the armature (19) toward the open position; and When the armature (19) approaches the open position, the secondary electromagnet (12) is also activated so that the secondary electromagnet (12) generates a magnetic force that attracts the armature (19) toward the secondary armature (17), thereby slowing down the movement of the armature (19) toward the open position.

7. The electromagnetic injector (1) according to claim 6, wherein: The control unit (20) is configured to deactivate the secondary electromagnet (12) before the armature (19) reaches the open position.

8. The electromagnetic injector (1) according to claim 6, wherein: The control unit (20) is configured to close the injection valve (7) so as to: The main electromagnet (11) is closed, so that the armature (19) is pushed to the closed position by the elastic force generated by the closing spring (10); and When the armature (19) approaches the closed position, the main electromagnet (11) is activated so that the main electromagnet (11) generates a magnetic force that attracts the armature (19) toward the main armature (14), thereby slowing down the movement of the armature (19) toward the closed position.

9. The electromagnetic injector (1) according to claim 8, wherein: The control unit (20) is configured to deactivate the main electromagnet (11) before the armature (19) reaches the closed position.

10. The electromagnetic injector (1) according to any one of claims 1 to 9, wherein: The control unit (20) is configured to deactivate the secondary electromagnet (12) before the plunger (8) reaches the open position.

11. The electromagnetic injector (1) according to any one of claims 1 to 9, wherein: The control unit (20) is configured to close the injection valve (7) so that The main electromagnet (11) is closed, so that the plunger (8) is pushed to the closed position by the elastic force generated by the closing spring (10); and When the plunger (8) approaches the closed position, the main electromagnet (11) is activated so that the main electromagnet (11) slows down the movement of the plunger (8) towards the closed position.

12. The electromagnetic injector (1) according to claim 11, wherein: The control unit (20) is configured to deactivate the main electromagnet (11) before the plunger (8) reaches the closed position.

13. A method for controlling an electromagnetic fuel injector (1), comprising: A tubular support body (4); a spray nozzle (3) arranged at the end of the support body (4); an injection valve (7) connected to the injection nozzle (3); a plunger (8) movable to regulate the flow of fuel through the injection nozzle (3) between a closed position and an open position of the injection valve (7); An electromagnetic actuator (6), the electromagnetic actuator being provided with a main electromagnet (11) and a secondary electromagnet (12), the main electromagnet being configured to apply a force to the plunger (8) when it is activated, the force pushing the plunger (8) toward the open position of the injection valve (7), and the secondary electromagnet being configured to apply a force to the plunger (8) when it is activated, the force pushing the plunger (8) toward the closed position of the injection valve (7); and a closing spring (10) configured to push the plunger (8) toward a closed position of the injection valve (7); In order to open the injection valve (7), the control method comprises the steps of activating the main electromagnet (11) so that the main electromagnet (11) generates a magnetic force that moves the plunger (8) towards the open position, overcoming the elastic force of the closing spring (10); The control method is characterized in that it includes the step of activating the secondary electromagnet (12) during the opening of the injection valve (7) and when the plunger (8) is close to the open position, so that the secondary electromagnet (12) generates a magnetic force that slows down the movement of the plunger (8) towards the open position.

14. The control method according to claim 13, comprising the following steps: Turning off the main electromagnet (11) causes the plunger (8) to be pushed to the closed position by the elastic force generated by the spring (10); and When the armature (19) approaches the closed position, the main electromagnet (11) is activated so that the main electromagnet (11) slows down the movement of the plunger (8) towards the closed position.

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