EP2461012B1 - Electromagnetic actuator module and injection valve - Google Patents

Description

State of the art

The invention relates to an electromagnetic actuator module, suitable in particular for fuel injection valves or fluid injectors, and an injection valve with an electromagnetic actuator module.

From the US 5,903,204 respectively. EP 2 177 748 An electromagnetic actuator is known. Such electromagnetic actuators based on the eddy current principle can be applied inter alia in the metal forming technique, for plastic, in particular thermoplastic, and explosive processing and shaping of small metallic construction elements with complex geometries. In order to achieve a mechanical stress in the known electromagnetic actuator, which allows the plastic deformation of metal, very high currents are briefly impressed in specially designed excitation coils of the actuator. The current densities can reach several 100 amperes per mm ² . The rapidly variable currents in turn induce very dynamic eddy currents in the metal to be processed. These interact with the magnetic field of the excitation current and form a very high repulsive impulse force which, with a corresponding construction of the working mold, is able to deform the small workpiece located there. The temporal courses of these exciting currents have a pulse-like character and a very short duration compared to their working period. As a result, the resulting heat is absorbed quasi-adiabatically by the construction. Thereafter, this is returned to the cooling system in the relatively long energization break. The The resulting magnetic field of the exciting coil can reach values of more than 10 Tesla for a short time and in a very limited space.

To generate such current pulses, it is conceivable that circuits are used in which the electrical energy is converted into the electromagnetic energy of the actuator by an extremely fast discharge of a suitably dimensioned capacitor or capacitor banks.

For the design of eddy current actuators, however, relatively large pulse capacitors and switches are required for this purpose. For example, using these components with a rated voltage well in excess of 1000 V results in large volumes and costs, which are heavily dependent on the voltage level used. Another problem is the impedance of the leads. This should be as small as possible. However, this is in contradiction to the volume of construction of the elements and the necessary isolation distances for high voltage components used. The consequence is that the components, such as capacitors, isolators, switches and the charger, are correspondingly expensive. In addition, it is relatively difficult to achieve an inexpensive and meaningful and automitive suitable integration of the entire actuator.

To generate pulses of higher voltage, it is conceivable that a multi-stage arrangement, such as a Marx generator, is used. Such a Marx generator consists of a series connection of several discharge circuits with capacitors. This gives a multi-stage arx generator. With a charging DC voltage, all surge capacitors can be charged in parallel and at the same time. If all of the surge capacitors are charged to their quasi-steady end value of the voltage, then followed by a trigger circuit, the closure of multiple switches, each associated with a surge capacitor. This changes the topology of the circuit and all capacitors are discharged seriel via the excitation winding of the actuator. The voltage is multiplied and the resulting currents of the exciting coil of the actuator significantly higher and faster. The ignition

(Switching) of the individual pitch circles can also be done sequentially or with a delay. However, the problem of the high voltage of the circuit components and the required dielectric strength is also in this embodiment. In particular, the circuit elements are in the end electrically connected to each other and large electrical potential differences are present. Thus, a reduction based on the Marx generator circuit, a cost reduction for the chargers and partly the capacitors can be achieved. During the discharge, however, the electrical components are again connected in series, which results in large voltage differences, which again causes high costs and space problems in this regard.

Thus, in this way the formation of the time course of Aktorstoßkraft is not possible and not suitable for the construction of appropriate force controls. In particular, only a shock pulse can be generated. Furthermore, the time profile of the generated pulse can not be influenced.

Disclosure of the invention

The electromagnetic actuator module according to the invention with the features of claim 1 and the injection valve according to the invention with the features of claim 15 have the advantage that an improved design is possible. Specifically, an amplified amplitude can be achieved in a low-cost configuration.

The measures listed in the dependent claims advantageous refinements of the specified in claim 1 electromagnetic actuator module and the injection valve specified in claim 15 are possible.

Advantageously, the injection valve can serve as a fuel injection valve or as a fluid injector for exhaust aftertreatment. However, the injector is also suitable for other applications.

In the embodiment as a fuel injection valve or the like, the necessary ejection of the fluid, in particular of the fuel, from the nozzle is generated by a shock wave in the liquid. For the generation of the shock wave, it is necessary that very large energy densities are generated in a very short time. For example, the shock wave may be amplified in one channel, thereby directing high pressure to the nozzle. With this actuator principle, the question of physical limits is central to the impulsive development of force. Here, the magnetic saturation of the ferromagnetic materials, the time constants in the energy transfer chain and the dissipation of the resulting heat are essential. The demands on the dynamics of the shock wave injector for the injection systems of motor vehicles are very high. For the initiation of the shock wave in the fuel, the energy of a few joules in the time range of a few microseconds must be implemented. This results purely mathematically a pulse power in the megawatt range.

In an actuator based on the eddy current principle, it is possible that the magnetic flux propagates completely in a non-ferromagnetic environment. In this principle, it is advantageous that the inductance considered by the primary coil or the primary coils is very small. This allows the realization of very fast current rising edges and a relatively small parameter dispersion. With this principle, it is possible to meet the high demands.

A possible goal is the design of a fast, efficient and cost-effective electromagnetic actuator module for the direct control of a shock wave injector. The actuator module should be as small and robust as possible and suitable for the operating conditions in the automotive industry. One possible focus is that in the fluid of the injector, a shock wave is generated, the fuel injection should allow the most accurate possible dosage. By an advantageous embodiment of the power transmission and the use of the electromagnetic actuator module with an active membrane and a passive membrane energy conversion can be improved and the excitation force of the shock wave can be significantly increased. Such an actuator module can be used together with the associated Fuel injection valve used in an injection system of a motor vehicle.

Advantageously, the time profile of the impact force of the actuator module can be formed. In particular, more than one shock can be generated in one operation. In addition, the spatial pressure distribution, for example as a function of a membrane diameter, can be influenced. It is also possible that the current density in the membrane and thus also the local heat distribution in the membrane are influenced. In addition, the shockwave can be generated with a reduced voltage. As a result, the costs for the insulation, capacitors, switching elements, in particular thyristors or relays, and the corresponding safety measures can be reduced. In addition, the required parameters of the shock wave, in particular force values and their time derivatives, can be better influenced by the available voltage.

Thus, a fast, efficient and inexpensive electromagnetic actuator module can be created. In this case, a variable force shaping is possible, which is important for the requirements for the formation of shock waves in a liquid or a solid. Depending on the configuration of the actuator module and its control, temporal changes in the impact force shaping can be achieved. The actuator module can also be made small and robust. As a result, the actuator module is particularly suitable for automotive applications, in particular for fuel injection systems and fuel injection valves. In this case, the structure can be designed so that the application of components with higher voltage, in particular of more than 1000 V, is avoided.

Advantageously, the actuator module can be modular. In this case, the stator may be formed from a plurality of separate windings (exciter windings), which act in a specific order on the diaphragms of the actuator module. The currents of these windings can be set independently of each other and individually in an advantageous manner.

The electromagnetic actuator module can be used to generate shock waves in liquids or solids. The first application is so-called shock wave injectors. The controlled ejection of the fluid from a nozzle is generated by a shock wave in the liquid. For the generation of shock waves, it is necessary to generate very high energy densities in a very short time. The shock wave can then be amplified in a channel and directed at high pressure on the nozzle.

The generation of a very high and dynamic useful force of the actuator module can take place between a primary coil (winding) and the active membrane, which is preferably arranged in the immediate vicinity, with the active membrane acting quasi as a short-circuited secondary coil. The useful force comes about through the interaction of the very dynamic electromagnetic field of excitation of the primary coil and the eddy currents induced by it in the active membrane. This impulse force has a spatially and temporally variable power density. The force density results here at least approximately from the magnetic induction of the field and the current density in the membrane. The excitation field is generated by a brief impression of extremely high currents in the primary coil of the actuator module. Short term here means preferably in the microsecond range. Extremely high currents mean peak values of several 100 A per mm ² . The temporal courses of the excitation currents are rapidly changeable and shaped so that their derivation can likewise reach very high values. The resulting magnetic field of the excitation coil can thus reach values above 10 Tesla for a short time. As an advantage, significantly smaller nominal voltages of the components of the actuator module, in particular of the capacitors, switches and the insulation can thus be made possible. In addition, a flexible temporal shaping of the impact force of the actuator module is possible. Furthermore, the impact force is optionally adjustable. In addition, a compact design can be achieved.

Preferably, the system is modular. In this case, instead of a single excitation coil and several sub-coils, that is, several windings are used. The resulting flooding of the actuator module is then composed of the sum of the partial flows through the individual Windings are caused. The partial flux of a winding results here as a product with a multiplier which is equal to the current through the considered coil or winding, and a multiplicand, which is equal to the number of turns of the considered coil or winding.

Due to the effect of these partial flows in the region of a membrane arise in the volume of the respective membrane position-dependent, in particular as a function of the radius, and time-dependent eddy currents. These eddy currents create their own reaction field. The resulting magnetic field in turn has a certain flux density and results from the sum of the excitation fields of the individual coils (windings) and the generated reaction field. The vectorial force density in the membrane results at least approximately as a cross product of the flux density of the resulting magnetic field and the time-dependent eddy current in the membrane under consideration. The total force resulting from the force density results from integration of this force density across the membrane surface.

Each of the partial vortex currents in the membrane generates a repulsive force on the inducing primary coil via the magnetic field generated by it. The resulting repulsive force between the excitation coils in the stator and the membrane is formed by the addition of the optionally staggered partial forces of the coil sections.

Thus, a shock wave can be generated in a liquid or in a solid having a desired shape. The necessary course of the acceleration of the masses, which comprises the membrane mass and the time-dependent mass of the accelerated liquid at the front of the shockwave to be generated, can hereby be designed accordingly. The acceleration of the membrane results here as a product with a multiplier, which is the sum of the optionally staggered partial forces of the partial coils on the membrane, and a multiplicand, which is a fractional value with a dividend equal to 1, and a divisor, the is the sum of the membrane mass and the time-dependent mass of the accelerated liquid at the front of the shock wave to be generated. The dependence of the mass of the medium on the time describes the Formation of the shock wave in the medium, which is driven by the membrane. Depending on the application and operating conditions as well as the operating mode, the resulting acceleration may differ significantly.

In conventional systems, this build-up of force is rigid and dependent on the electrical parameters of the system, particularly the capacitance, the line impedance, the number of turns, the impedance of the excitation coil, and the position of the diaphragm. The vote of the current build-up and the membrane force can then be done only by the charging voltage of the surge capacitor and optimal formation of the shock wave is possible only by consuming adjustments to the design parameters.

In the system according to a possible embodiment of the invention, there is the possibility that this force is formed by the variable time offset of the pulse distribution of the currents in the sub-coils. In addition, the design of design parameters of the partial coils, in particular the number of turns, the winding cross-section and their arrangement, an improved spatial distribution of the mechanical stress and the temperature distribution can be achieved in the membrane.

Another advantage results from a segmentation of the excitation coil into a plurality of partial coils (windings), since this makes it possible to lower the operating voltage. If, for example, N partial coils are provided, then the resistance and the inductance of each of the individual partial coils can be at least approximately smaller by a factor of 1 / N than that of a non-segmented coil.

Since the instantaneous maximum value is substantially dependent on the resistance of the coil, a much smaller voltage is sufficient to produce a comparable peak value of the current.

On the other hand, the pulse currents in a segmented discharge circuit can be substantially shorter than in a large single coil. Starting from the same energetic content and a (1 / N) -fold voltage at the sub-coils result There are N partial capacitors with a capacitance that is a fractional value with a dividend that is the total capacitance of a single coil and a divisor that is the square root of N. For the frequency of the overshoot of the first half-wave, this means multiplying the frequency by a factor that is a power with a base equal to the number N of the sub-coils or sub-capacitors and a potential exponent that is 1.5. This means that the currents of the sub-coils run much steeper and their duration is shorter.

The operating principle of the electromagnetic actuator module can in this case use the interaction between the current-carrying conductors or areas. With an electronic circuit, a pulse-like current can be impressed in the primary coil or the primary coils. Due to the very steep rising edge of the current eddy currents are induced in all surrounding conductors. The size and shape of these currents depends on the geometry of the conductors and their material compositions. The actuator module is designed so that the eddy currents propagate mainly in the highly conductive membranes. The thickness and, if required, material composition of the two membranes can be chosen differently and depend strongly on the operating temperature. A hybrid construction comprising a copper layer in the inner region and a layer of amorphous ferromagnetic material, for example Metglas, with a very narrow hysteresis loop of the magnetization characteristic is advantageous here. Such a construction may increase the effective size and penetration depth of the eddy currents, depending on the level of magnetic induction.

Preferably, the eddy current generation takes place with a high efficiency. For this purpose, it is advantageous that highly conductive materials, in particular copper, are used in the exciter coil.

In the timing of the control of the electromagnetic actuator module, the ratio of the operating period and the active time, which is dependent on the rotational speed of the internal combustion engine, for example, be greater than 2000. This results in a short active time in the millisecond range, in which very high Current densities occur. The heating of the electrical conductors is thus very fast, almost adiabatic. After the brief energization follows a relatively long phase of heat dissipation from the electrical conductors in the cooling system. Consequently, the physical limits to force generation are primarily not heat generation but high mechanical forces within the winding. These forces must be sufficiently absorbed and supported. For this purpose, the stator can be configured in an advantageous manner by an open titanium band. The construction parts of the actuator module, in particular of the housing, are in this case, as far as possible, made of non-ferromagnetic materials, these having, if possible, a very good thermal conductivity.

The electromechanical design of the actuator module is designed so that after a pulse-like energization first the lighter active membrane responds, deforms and generates the first steep tip of the shock wave front in the fluid or solid. The structural design can be done in particular on the strength of the membranes and the stiffness of spring elements or the like. The active membrane reacts first, as it is preferably located immediately adjacent to the winding and thus repelled directly from the winding. The passive membrane on the other side reacts with a slight delay. For this purpose, the passive membrane may additionally be made thicker and heavier, so that the mechanical and electromechanical time constants are greater than in the case of the active membrane. The time constants are adjusted by the geometry and material choice so that the build up of the electromagnetic response in the passive membrane occurs with a slight delay.

Due to the reaction force of the housing, which can be composed of several housing parts, a second wave of impact force is generated. This second wave of impact strength enhances the first wave of impact force. By designing the time constants in the two subsystems of the membranes, the resulting impact force, which results from the sum of the two waves of impact force, at the interface between the active membrane and the fluid or the Solid body reinforced. Thus, as it were, there is a superposition, whereby a total shock wave is designed.

It is advantageous that an outer side of the passive membrane is at least substantially coated with an amorphous layer. The amorphous layer gives a high relative permeability. For example, an amorphous metal layer having a relative permeability greater than 10,000 may be selected. The membrane itself can be designed here as a copper membrane. As a result, the flow is concentrated even at high frequencies without significant losses. The passive membrane is preferably designed to be ideally rigid. Accordingly, it is advantageous that the active membrane is at least substantially coated with an amorphous layer. In particular, an amorphous metal coating with a relative permeability of more than 10,000 may also be selected in this case. Thus, the magnetic flux is partially amplified and concentrated at high frequencies without significant losses through the active membrane.

It is advantageous that the passive membrane has at least one passage opening, which is arranged at least approximately in a center of an outer side of the passive membrane, and that an electrical supply line for the winding is guided through the passage opening to the stator. If several windings are provided, the electrical supply line is then led to the plurality of windings. Thus, a primary coil can be formed from a single coil, i. a single winding, or several sub-coils, i. several windings, be formed. Here, it is also advantageous that the electrical supply line is designed as a flexible and movable electrical supply line. In the case of a rigid electrical supply line there is the problem that it breaks if necessary. Due to the flexible and movable design, the operation over the life of the actuator module can be guaranteed.

Moreover, it is advantageous that the passive membrane is supported on the housing part via a non-linear spring element. Here, it is also advantageous that a stamp is provided, which is connected via a screw connection with a housing part. Specifically, the screw can be connected via a Fine thread be configured. Here, it is also advantageous that a ceramic part is provided, which is arranged between one of the passive membrane facing side of the punch and the passive membrane, that the passive membrane is supported on the non-linear spring element on the ceramic part and that by the screw a bias of the non-linear spring element is adjustable. Thus, the spring constant of the spring element in the initial state can be adjusted via the bias. As a result, a precise adjustment of the desired spring constant is possible. In particular, if necessary, a readjustment is possible. The plunger may thus serve to adjust the primary stiffness of the passive membrane with respect to the housing part. The spring constant is then set in zeroth approximation to the desired value. Through the ceramic part of the desired pressure can be generated.

It is also advantageous that on the active membrane in an edge region of the active membrane, a spring receptacle is designed which receives an annular spring element and that the active membrane is supported via the annular spring element at least on a housing part.

Thus, the two membranes can be clamped between one or more housing parts in an advantageous manner. Here, it is also advantageous that the active membrane is biased against the passive membrane and that the active membrane is pressed via the stator to the passive membrane. In this way, a pressure of the passive membrane, the stator and the active membrane is given in this order. A gap can be configured laterally between the two diaphragms, so that the two diaphragms do not bear against one another but are stretched over the stator with respect to one another.

It is also advantageous that the passive membrane has an approximately lenticular recess, that a cross-sectional area of the lenticular recess perpendicular to an actuating direction of the active membrane comprises at least approximately a cross-sectional area of the winding of the stator and that a cooling system is provided which a cooling fluid through the lenticular Recess of the passive membrane leads. By the Lens-shaped recess of the passive membrane, the stiffness of the passive membrane can be improved in the operating direction. In addition, the lenticular recess allows for improved cooling of the passive membrane. Cooling of the passive membrane is then indirectly followed by cooling of the remaining components, in particular of the windings of the stator.

It is also advantageous that at least one cooling passage is configured in at least one housing part. As a result, the cooling of the actuator module can be further improved.

Advantageously, a plurality of windings are provided, which are individually controllable, wherein a controller and a plurality of windings associated shock capacitances are provided and wherein the controller is designed to generate the impulse capacitances to generate pulse currents through the windings at predetermined times. In this case, the impact capacitances are preferably designed such that the generated pulse currents have steep rising edges. As a result, instead of a single coil (winding) a division into several sub-coils (windings) take place. As a result, the control of the actuator module can be improved.

Brief description of the drawings

• Fig. 1 ein Brennstoffieinspritzventil mit einem elektromagnetischen Aktormodul in einer auszugsweisen, schematischen Schnittdarstellung entsprechend einem ersten Ausführungsbeispiel der Erfindung;
• Fig. 2 ein Brennstoffeinspritzventil mit einem elektromagnetischen Aktormodul entsprechend einem zweiten Ausführungsbeispiel der Erfindung in einer auszugsweisen, schematischen Schnittdarstellung;
• Fig. 3 ein Signalverlaufdiagramm in einer schematischen Darstellung zur Erläuterung der Funktionsweise der Erfindung;
• Fig. 4 eine schematische Darstellung eines elektromagnetischen Aktormoduls entsprechend einem dritten Ausführungsbeispiel der Erfindung und
• Fig. 5 ein Signalverlaufdiagramm zur Erläuterung der Funktionsweise des elektromagnetischen Aktormoduls entsprechend dem dritten Ausführungsbeispiel der Erfindung.

Preferred embodiments of the invention are explained in more detail in the following description with reference to the accompanying drawings, in which corresponding elements are provided with corresponding reference numerals. It shows:

• Fig. 1 a Brennstoffieinspritzventil with an electromagnetic actuator module in a partial, schematic sectional view according to a first embodiment of the invention;
• Fig. 2 a fuel injection valve with an electromagnetic actuator module according to a second embodiment of the invention in a partial, schematic sectional view;
• Fig. 3 a signal waveform diagram in a schematic representation for explaining the operation of the invention;
• Fig. 4 a schematic representation of an electromagnetic actuator module according to a third embodiment of the invention and
• Fig. 5 a waveform diagram for explaining the operation of the electromagnetic actuator module according to the third embodiment of the invention.

Embodiments of the invention

Fig. 1 shows an injection valve 1 designed as a fuel injection valve 1 with an electromagnetic actuator module 2 in a partial, schematic sectional view according to a first embodiment of the invention.

The fuel injection valve 1 is particularly suitable for a fuel injection system of a motor vehicle. The electromagnetic actuator module 2 is preferably used in such a fuel injection valve 1. Another preferred use of the injection valve 1 or the actuator module 2 is in systems for exhaust aftertreatment. The injection valve 1 is suitable for fluid production, in particular in an exhaust aftertreatment in vehicles, for. B. for a denoxification. However, the fuel injection valve 1 according to the invention and the electromagnetic actuator module 2 according to the invention are also suitable for other applications.

The electromagnetic actuator module 2 has housing part 3, 4. Furthermore, the fuel injection valve 1 has a valve body 5. The valve body 5 can in this case serve as a further housing part 5 of the electromagnetic actuator module 2. As a result, the electromagnetic actuator module 2 can be made compact.

The electromagnetic actuator module 2 has a stamp 6. The punch 6 has on its outer side 7 a fine thread 8, with which the punch 6 in a corresponding fine thread 9 of the valve body 5 is screwed. The punch 6, the housing part 3 and the housing part 4 are aligned with respect to a longitudinal axis 10 of the actuator module 2.

The electromagnetic actuator module 2 has an active membrane 15, a passive membrane 16 and a stator 17 with a winding 18. Between the active membrane 15 and the passive membrane 16, a gap 20 is provided in an edge region 19. As a result, the two membranes 15, 16 do not touch each other directly. The stator 17 with the winding 18 is disposed between the membranes 15, 16. In this case, there is a pressure between the passive membrane 16 and the stator 17 and the active membrane 15. Thus, a mechanical operative connection between the membranes 15, 16 via the stator 17th

The active membrane 15 has an outer side 21. Furthermore, the passive membrane 16 has an outer side 22. The outer side 21 of the active membrane 15 faces away from the outer side 22 of the passive membrane 16. On the outer side 21, the active membrane 15 is at least substantially coated with an amorphous layer 23. Furthermore, the passive membrane 16 is coated on its outer side 22 substantially with an amorphous layer 24. The amorphous layers 23, 24 are configured, for example, as amorphous metal layers having a relative permeability of more than 10,000. The magnetic flux that can be generated by the winding 18 can thereby be bundled even at high frequencies without significant losses. The membranes 15, 16 may be formed of copper, for example.

The passive membrane 16 has a passage opening 25 in the middle of the outer side 22. Through the passage opening 25, an electrical supply line 26 with conductors 27, 28 is guided to the stator 17. Via the electrical supply line 26, the winding 18 is connected to a controller 29. The conductors 27, 28 of the electrical supply line 26 are designed to be flexible and movable. Thus, a certain movement of the stator 17 is made possible relative to the housing part 5, without the electrical supply line 26 is damaged.

The electromagnetic actuator module 2 has an annular spring element 30. The spring element 30 is in this case preferably designed as a non-linear spring element 30. The passive membrane 16 is supported on the housing parts 3, 5 via the spring element 30. In particular, the passive membrane 16 is supported via the non-linear spring element 30 on a disk-shaped ceramic part 31, which is held over the punch 6. Here, the punch 6 acts on the ceramic part 31, the non-linear spring element 30 with a bias. The ceramic part 31 is arranged between a passive membrane 16 facing side 11 of the punch 6 and the passive membrane 16. The spring element 30 is thereby biased, wherein a certain spring constant is set according to the biasing force. Thus, the spring constant of the non-linear spring element 30 can be adjusted in zeroth approximation via the plunger 6.

In addition, a further spring element 32 is provided. The further spring element 32 is in this case arranged between the housing part 4 and the active membrane 15. The active membrane 15 has in a peripheral region 33 of the outer side 21 a receptacle 34 which receives the annular spring element 32. The annular spring element 32 may in this case have a circular cross-section in the initial state. Thus, the active membrane 15, the stator 17 and the passive membrane 16 between the housing part 4 and the housing part 3 are reliably positioned. This allows a degree of flexibility.

If the system were freely arranged from the membranes 15, 16 and the stator 17, then, when the winding 18 is energized, a repulsive force would act both on the active membrane 15 and on the passive membrane 16. In this case, the active diaphragm 15 would be actuated in an actuating direction 35 of the active diaphragm, while the passive diaphragm 16 would be actuated counter to the actuating direction 35. However, since the passive membrane 16 is supported on the housing parts 3, 5, there is an increased actuation of the active membrane 15 in the actuation direction 35. Thus, it is precisely by the presence of the passive membrane 16 to an increased actuation of the active membrane 15th

When the winding 18 is energized, a magnetic force is exerted by the winding 18 on the active membrane 15. In addition, a magnetic force is exerted by the winding 18 on the passive membrane 16. In the course of time, therefore, there is a first pulse, which is caused on the direct actuation of the active membrane 15 due to the energization of the winding 18. Furthermore, there is subsequently a second pulse, which is based on the magnetic force exerted by the winding 18 on the passive membrane 16. This results in a mechanical shock, which is reflected by the other components, in particular the ceramic part 31, the punch 6 and the housing part 5. This additional, reflected shock then acts via the stator 17 in addition to the active membrane 15. The second pulse thus amplifies the first pulse. Thus, essentially two power pulses add up. Depending on the design of the electromagnetic actuator module 2, these two force pulses may be more or less resolved. In particular, it is possible that the two force pulses are superimposed so far that they are no longer resolved and in the sum only results in an amplified force pulse. Due to the design of the electromagnetic actuator module 2, however, it is also possible that by a certain time interval between the two force pulses, a resolution takes place, whereby the two force pulses are at least partially separated perceptible.

The fuel injection valve 1 has a fuel passage 40. During operation of the fuel injection valve 1, the fuel channel 40 is filled with fuel 41. By the deflection of the active membrane 15 of the electromagnetic actuator module 2 shock waves 42 are generated in the fuel 41. Depending on the resolution of the two force pulses, this results in a corresponding configuration of the shock waves 42 in the fuel 41. The shock waves 42 pass through the fuel channel 40, wherein according to the configuration of the fuel channel 40, a pressure gain is possible. Thereby, an exciting force for injecting fuel into a combustion chamber of an internal combustion engine or the like can be suitably generated.

For example, the electromagnetic actuator module 2 may be configured so that after a pulse-like energization of the winding 18, a first Force pulse for the deflection of the active membrane 15 is generated. The passive membrane 16 may be made thicker than the active membrane 15 so that it is heavier and thus the mechanical and electromechanical time constants are greater. As a result, the passive membrane 16 reacts with respect to the active membrane 15 with a slight delay. By the reaction force of the housing, the force pulse is then returned and guided to the active membrane 15. Thus, there is a second deflection of the active membrane 15, which can also enhance the first deflection. By the interpretation of the time constant, the resulting impact force and thus the generated shape of the shock wave 42 can be designed.

In order to dissipate the thermal energy generated during operation, the housing part 3 has cooling channels 43, 44 in this exemplary embodiment. Through the cooling channels 43, 44, a coolant is passed. In this embodiment, the passage opening 25 is sealed by a sealing element 45.

In order to advantageously transfer the high mechanical forces to the active membrane 15, the stator 17 has an opened titanium band 46. On the titanium band 46, the winding 18 is arranged. As a result, the winding 18 is suspended stiff.

Thus, the passive membrane 16 serves as a reaction membrane 16. The additional impact energy that arises in the passive membrane 16, thus transmits via the stator 17, in particular the winding 18 of the stator 17, on the active membrane 15 and amplifies the shock wave. By designing the rigidity of the connection or support of the passive membrane 16 with respect to the housing, in particular the housing parts 3, 5, the time course of the mechanical stress in the active membrane 15 and thus also the shape of the shock wave of the electromagnetic actuator module 2 can be amplified and be shaped.

The controller 29 may include a power electronic assembly. In this case, for example, by rapid discharge of pulse capacitors, a pulse voltage can be generated. The leads, in particular the electrical supply line 26, and the winding 18 have inductances. By the Co-operation of the inductors and the pulse capacitor, a stator current in the winding 18 is constructed like a pulse. In the magnetic system of the stator coil (winding) 18 and the two membranes 15, 16 creates a magnetic field, which can be described by concatenated magnetic fluxes. The coupling of the magnetic fluxes is comparable to a three-winding transformer. The chained flows generate eddy currents in the two membranes 15, 16 with a corresponding delay.

The size, spatial and temporal distribution of these eddy currents can be designed by the geometry, in particular thickness, and the material of the membranes 15, 16 so that their interaction with the stator generates the desired, in particular maximum, effect of the shock wave force. The interaction of the stator current and the eddy currents produces a force or a force impulse which flows directly via the active membrane 15 to the front of the shock wave 42 in the Fuel 41 is transmitted. The second force or the second force pulse is added as a second, delayed wave the first force pulse. Thus, the first power pulse can be amplified. A portion of this force pulse is transmitted directly to the active membrane 15 via the stator 17. Another part comes as a delayed reaction via the spring element 30, which is arranged between the passive membrane 16 and the mechanical support (housing), and in turn via the stator 17 to the active membrane 15 and at the front of the shock wave in the fuel 41st The sum of all forces acting on the active membrane 15 gives the resulting distributed mechanical stress in the active membrane 15. Here, there is a temporal dependence. By a suitable embodiment of the electromagnetic actuator module 2 and especially the active membrane 15, the shape of the shock wave 42 can be focused.

Fig. 2 shows a fuel injector 1 with an electromagnetic actuator module 2 in a partial, schematic sectional view according to a second embodiment of the invention. In this embodiment, the passive membrane 16 has a lenticular recess 50. A cross-sectional area 51 of the lenticular recess 50 perpendicular to The actuation direction 35 in this case comprises at least approximately a cross-sectional area 52 of the winding 18. The cross-sectional areas 51, 52 are oriented perpendicular to the actuation direction 35 and thus perpendicular to the longitudinal axis 10. In particular, the cross-sectional area 51 of the lenticular recess 50 may be at least approximately the same size as the cross-sectional area 52 of the winding 18. Due to the lenticular recess 50, the passive membrane 16 has inner sides 53, 54, which face each other. The passive membrane 16 may in this case be designed in the shape of a vault, whereby a mechanical stability, in particular rigidity, is improved. Specifically, the passive membrane 16 can thus be made stiff with respect to the actuation direction 35.

In addition, in this embodiment, a cooling system 60 is provided, which leads a cooling liquid into the lenticular recess 15 in and out again. For this purpose, an inlet channel 61 and a drainage channel 62 are guided together with the electrical supply line 26 through the passage opening 25 on the outer side 22 of the passive membrane 16 in the lenticular recess 50. In this case, cooling liquid can flow from the inlet channel 61 into the lenticular recess 50 in a suitable manner. Accordingly, cooling liquid can flow out of the lenticular recess 50 via the drainage channel 62 in a suitable manner. In this case, a flow can be generated in the lenticular recess 50, which is illustrated by arrows 63, 64. Thus, the cooling capacity is significantly increased.

Fig. 3 shows a signal flow diagram in a schematic representation for explaining the operation of the invention. In this case, the time is plotted on the abscissa 65, while at the ordinate 66, the resultant force acting on the active membrane 15, that is, the sum of all forces, is plotted. On the active membrane 15 acts first a first momentum 67, which is caused by the magnetic force from the winding 18 to the active membrane 15. This is followed by second fuel 68, which partially overlaps with the first force 67. In the illustration here is a partial resolution of the two force pulses 67, 68 shown, as illustrated by the two peaks. Due to the superposition of the two power surges 67, 68 is a maximum Total force 69 greater than a maximum force 70 of the first impulse 67. This causes a correspondingly greater deflection of the active membrane 15. By the two force impulses 67, 68 at least approximately an active time 71 of the electromagnetic actuator module 2 is determined. After an operating period 72 of the electromagnetic actuator module 2, further force pulses 67 ', 68' are connected. In this case, the second impulse 68 'overlaps with the first impulse 67'. The length of the operating period 72 is variable within certain limits. For example, the length of the operating period 72 depends on the speed of the internal combustion engine. For example, a ratio of the operating period 72 to the active time 71 may typically be greater than 2000. The active time 71 and the operating period 72 are shown in the diagram only schematically and not to scale.

Fig. 4 shows the controller 29 with a plurality of windings 18A, 18B, 18C of the electromagnetic actuator module 2 of a fuel injection valve 1 according to a third embodiment in a schematic representation. In this embodiment, three windings 18A to 18C are shown. These three windings 18A-18C are used instead of a single winding 18 and are disposed between the membranes 15,16. In this embodiment, the active membrane 15 is shown schematically.

The controller 29 has a pulse generator 80. Further, charging circuits 81A, 81B, 81C are provided which serve to charge surge capacitances 82A, 82B, 82C. The charging circuits 81A to 81C are fed by a charging voltage. For this example, a high-voltage transformer may be provided, the high voltage is converted via a rectifier in the rectified charging voltage for the charging circuits 81A to 81C. The charging circuits 81A to 81C have suitable charging resistors, for example, to charge the surge capacitors 82A to 82C in the desired time. The charging process takes place here, for example, relatively slowly, for example in the millisecond range. The pulse generator 80 generates trigger signals which are fed via lines 83A, 83B, 83C to electronic switches 84A, 84B, 84C for triggering a switching operation. The switches 84A to 84C may be used as thyristors, for example be designed. When switching the electronic switches 84A to 84C, the surge capacitances 82A to 82C are switched to the individual windings 18A to 18C. As a result, pulse currents are generated in the windings 18A to 18C. The surge capacitances 82A to 82C discharge in this case via the pulse currents. The pulse generator 80, which serves as a trigger device 80, can output the individual switching signals for switching the switches 84A, 84B, 84C at freely programmable times. Thus, the pulse currents for the windings 18A-18C may be generated at appropriate times and not necessarily simultaneously.

Due to the very high rising edges of the pulse currents for the windings 18A to 18C eddy currents are induced in all surrounding conductors as a function of the penetration depth. The size and time of these eddy currents depends on the geometry of the conductors, their material composition and the penetration depth. The electromagnetic actuator module 2 is designed so that the eddy currents propagate, especially in the highly conductive membranes 15, 16.

In the Fig. 4 For example, magnetic fluxes 85A, 85B, 85C of the individual windings 18A, 18B, 18C are illustrated. In total, this results in a magnetic field or magnetic flux 86. This magnetic flux 86 penetrates in particular the active membrane 15, so that the eddy currents are generated in the active membrane 15. This results in an actuation of the active membrane 15 in the actuation direction 35.

The controller 29 may include further components. In particular, a freewheeling diode can be connected in each case between the individual lines. For example, a freewheeling diode may be connected between lines 87, 88 connecting the electronic switch 84A to the winding 18A. The same applies to the other windings 18B, 18C. Thus, in a current direction change, the respective winding 18A to 18C can be shorted. Such freewheeling diodes are advantageously in the in the Fig. 4 illustrated switches 84A, 84B, 84C integrated.

The eddy current generation in the membranes 15, 16 can be carried out with high efficiency by using highly conductive materials, in particular copper, for the membranes 15, 16.

Fig. 5 shows a waveform diagram illustrating the operation of the electromagnetic actuator module 2 with the controller 29 according to the third embodiment of the invention. In this case, the time is plotted on the abscissa. On the ordinate, the current pulses 90A, 90B, 90C, the resulting force 91 to the active membrane 15 and, for comparison, the deflection 92 in a single winding 18, wherein a structure of the electromagnetic actuator module 2 without passive membrane 16 is used. The additional effect of the passive membrane 16 is therefore in the illustration of Fig. 5 not considered.

By way of illustration, trigger times 93A, 93B, 93C are given to which the pulse generator 80 actuates the individual switches 84A through 84C. As a result, the individual windings 18A to 18C are successively passed through, which is illustrated by the current pulses 90A to 90C. The individual magnetic fluxes 85A to 85C result in a magnetic field 86 which exerts a resultant force 91 on the active membrane 15. Corresponding to the resulting force 91, there is also a deflection of the active membrane 15. Here, in particular, the steep rise is significant compared to a single-winding excitation, as illustrated by the curve 92.

Depending on the choice of the trigger times 93A to 93C, the force amplitude 91 can thus be formed. In particular, a total duration 94 can be influenced in a targeted manner. Due to the configuration of this temporal force form 91 and thus the corresponding excitation force for generating the shock wave 42, the energy conversion in the electromagnetic actuator module 2 can be made particularly effective and much better adapted to the specific properties of the medium 41, in particular of the fuel 41.

The ratio of the operating period of the electromagnetic actuator module 2 and the active energizing time of the individual exciting coils (windings) 18A to 18C may typically be greater than 1000. As a result, very high current densities can be applied in the microsecond range. The heating of the conductors is very fast, almost adiabatic. After the brief energization, a relatively long phase of heat dissipation from the conductors into the cooling system 60 follows. As a result, the physical limit to force generation is primarily not heat generation but high mechanical forces within windings 18A-18C. These forces can be adequately intercepted and supported. The structural parts of the actuator module 2 are in this case made of non-ferromagnetic materials which, if possible, have a very good thermal conductivity.

The electromechanical construction of the electromagnetic actuator module 2 is designed so that after a pulse-like energization first the lighter active membrane 15 responds, which is repelled by the windings 16A to 16C, and the first steep peak of the shockwave front is generated. The electromechanical design can be designed in particular on the strength of the membranes 15, 16 and their stiffnesses.

Thus, the electromagnetic actuator module 2 may include a plurality of windings 18A to 18C. The windings 18A to 18C are individually controllable by the controller 29 here. The controller 29 has a plurality of impact capacitances 82A to 82C associated with the individual windings 18A to 18C, which are discharged at predetermined timings (trigger times) 83A to 83C. By discharging the surge capacitances 82A to 82C at the trigger times 83A to 83C, pulse currents 90A to 90C are generated in the windings 18A to 18C. The surge capacitances 82A to 82C are configured such that the generated pulse currents 90A to 90C have steep rising edges 95A, 95B, 95C.

The invention is not limited to the described embodiments.

Claims (16)

1. Electromagnetic actuator module (2) in particular for fuel injection valves or fluid injectors, which is based on the eddy current principle, having a first diaphragm (15), which is called the active diaphragm in the text which follows, a second diaphragm (16), which is called the passive diaphragm in the text which follows, and a stator (17) which is arranged between the active diaphragm (15) and the passive diaphragm (16), wherein the stator (17) has at least one winding (18), so that eddy currents are induced and therefore repelling forces act on the diaphragms when current is applied to the winding, and wherein the passive diaphragm (16) is supported at least indirectly on at least one housing part (3, 5), so that operation of the active diaphragm (15) can be intensified when current is applied to the winding (18).
2. Electromagnetic actuator module according to Claim 1, characterized in that an outer side (22) of the passive diaphragm (16) is coated at least substantially with an amorphous layer (24).
3. Electromagnetic actuator module according to Claim 1 or 2, characterized in that the passive diaphragm (16) has at least one passage opening (25) which is arranged at least approximately in a centre of an outer side (22) of the passive diaphragm (16), and in that an electrical feed line (26) for the winding (18) is routed to the stator (17) through the passage opening (25).
4. Electromagnetic actuator module according to Claim 3, characterized in that the electrical feed line (26) is in the form of a flexible and/or movable electrical feed line (26).
5. Electromagnetic actuator module according to one of Claims 1 to 4, characterized in that the passive diaphragm (16) is supported on the housing part (3, 5) at least by means of a non-linear spring element (30).
6. Electromagnetic actuator module according to Claim 5, characterized in that a punch (6) is provided, the said punch being connected to a housing part (5) by means of a screw connection (7, 9), in that a ceramic part (31) is provided, the said ceramic part being arranged between a side (11) of the punch (6) which faces the passive diaphragm (16) and the passive diaphragm (16), in that the passive diaphragm (16) is supported on the ceramic part (31) by means of the non-linear spring element (30), and in that a preload of the non-linear spring element (30) can be adjusted by the screw connection (7, 9).
7. Electromagnetic actuator module according to one of Claims 1 to 6, characterized in that an outer side (21) of the active diaphragm (15) is coated at least substantially with an amorphous layer (23).
8. Electromagnetic actuator module according to one of Claims 1 to 7, characterized in that a spring receptacle (34) is designed on the active diaphragm (15) in an edge region (33) of the active diaphragm (15), the said spring receptacle accommodating an annular spring element (32), and in that the active diaphragm (15) is supported at least indirectly on a housing part (4, 5) by means of the annular spring element (32).
9. Electromagnetic actuator module according to one of Claims 1 to 8, characterized in that the passive diaphragm (16) has an at least approximately lens-like recess (50), and in that a cross-sectional area (51) of the lens-like recess (50) at least approximately includes a cross-sectional area (52) of the winding (18) of the stator (17) perpendicular to an operating direction (35) of the active diaphragm (16).
10. Electromagnetic actuator module according to Claim 9, characterized in that a cooling system (60) is provided, and in that the cooling system (60) is designed to route a cooling liquid through the lens-like recess (50) in the passive diaphragm (16).
11. Electromagnetic actuator module according to one of Claims 1 to 10, characterized in that at least one cooling channel (43, 44) is formed in at least one housing part (3).
12. Electromagnetic actuator module according to one of Claims 1 to 11, characterized in that the active diaphragm (15) acts on the passive diaphragm (16) with a preload, and in that the active diaphragm (15) is pressed against the passive diaphragm (16) by means of the stator (17).
13. Electromagnetic actuator module according to one of Claims 1 to 12, characterized in that a plurality of windings (18A, 18B, 18C) are provided, in that the windings (18A, 18B, 18C) can be driven individually, in that a controller (29) and a plurality of surge capacitors (82A, 82B, 82C) which are associated with the windings (18A, 18B, 18C) are provided, and in that the controller (29) is designed to discharge the surge capacitors (82A, 82B, 82C) at prespecified times (93A, 93B, 93C) in order to generate pulse currents (90A, 90B, 90C) through the windings (18A, 18B, 18C).
14. Electromagnetic actuator module according to Claim 13, characterized in that the surge capacitors (82A, 82B, 82C) are designed such that the generated pulse currents (90A, 90B, 90C) have steep rising flanks (95A, 95B, 95C).
15. Injection valve (1), in particular injector for fuel injection systems or fuel injectors, having an electromagnetic actuator module (2) according to one of Claims 1 to 14.
16. Method for operating an electromagnetic actuator module, which is based on the eddy current principle, or an injection valve having an electromagnetic actuator module of this kind, in which method a first diaphragm, which is called the active diaphragm in the text which follows, a second diaphragm, which is called the passive diaphragm in the text which follows, and a stator are provided, wherein the stator is arranged between the active diaphragm and the passive diaphragm and has at least one winding, so that eddy currents are induced and therefore repelling forces act on the diaphragms when current is applied to the winding, wherein the passive diaphragm is supported at least indirectly on at least one housing part, so that operation of the active diaphragm is intensified when current is applied to the winding (18).

Images