CN112863806B

CN112863806B - Method for triggering a solenoid valve and evaluation and control unit

Info

Publication number: CN112863806B
Application number: CN202011355552.6A
Authority: CN
Inventors: A·莱希勒; G·施托克迈尔
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2019-11-28
Filing date: 2020-11-27
Publication date: 2023-02-28
Anticipated expiration: 2040-11-27
Also published as: DE102019218480A1; CN112863806A

Abstract

The invention relates to a method for controlling a solenoid valve, comprising a magnet assembly having an electrical coil and a movably mounted magnet armature having a closing element, which is moved in a movement direction counter to the force of a return spring by means of the activation of the magnet assembly, wherein the closing element rests sealingly against a valve seat in the closed state of the solenoid valve and lifts off from the valve seat in the open state of the solenoid valve and adjusts the effective opening cross section of the solenoid valve, wherein at least one input variable influencing the armature movement or influenced by the armature movement is detected, wherein an armature stroke is estimated on the basis of the detected at least one input variable, and at least one electromagnetic damping variable for influencing the armature movement is calculated and output to the magnet assembly, wherein at least one characteristic map or at least one mathematical function is used to estimate the armature stroke and to calculate the at least one electromagnetic damping variable.

Description

Method for triggering a solenoid valve and evaluation and control unit

Technical Field

The invention relates to a method for triggering a solenoid valve and to an evaluation and control unit for carrying out the method.

Background

For conventional vehicle brake systems, normally closed solenoid valves are usually used as switching valves for achieving different safety functions. Switching noise is generated when such a solenoid valve is opened or closed. The noise is generated because the armature of the solenoid valve strikes the pole piece (stopper) of the valve at a high speed when the valve is open. When closed, the armature strikes the valve seat with the closing element. This results in a greater deceleration at the armature and thus a greater time-dependent pulse force in the valve. This can lead to switching noise and wear of the valve seat or valve closure element. In principle, this fact applies also to other switching valves which implement an ABS or ESP safety function.

A method and a device for triggering a solenoid valve are known, for example, from DE 10 2018 221 930 A1, which is published below. The solenoid valve comprises a closing body and a rest position, wherein the closing body can be moved away from the rest position in a movement direction. The method comprises the following steps:

a) presetting a target position of the closing body, b) receiving at least one input variable influenced by an actual position of the closing body, c) determining an estimated actual position from the at least one input variable, d) determining a control deviation from a difference between the target position and the actual position, e) generating a trigger voltage for triggering the solenoid valve by using the controlled variable, f) outputting the trigger voltage for triggering the solenoid valve.

Disclosure of Invention

The advantage of the proposed method for triggering a solenoid valve having the features according to the invention is that the impact speed of the closing element or the armature can be reduced. Switching noise and wear in the valve seat and at the armature are thereby reduced. In addition, the open period and the closed period of the switching valve can be variably set by the proposed method. This means that the switching valve can be switched slowly or quickly.

When the solenoid valve is switched, a voltage is induced in the magnetic circuit by the armature movement or the armature speed (this is also referred to as armature reaction) and is superimposed on the trigger voltage. This effect can cause a sudden drop in current, which reduces the magnetic force generated during switching. This effect is analogous to a velocity-dependent damping force which acts on the armature opposite to the direction of movement. The idea of the present invention application is to implement this effect as "electromagnetic damping" with adjustable gain and as a method for triggering a solenoid valve in an evaluation and control unit, so as to influence the armature movement or the armature speed. The effectiveness of the electromagnetic damping can be variably adjusted. In addition, the method for triggering the solenoid valve can be used for switching valves and regulating valves.

In the case of a regulating valve, the reciprocating oscillations can be damped in an advantageous manner. In addition, in position-controlled control valves, the desired position can be better controlled by means of an adjustable damping, so that the stability of the position control loop is increased or only possible in this way. In the case of a switching valve, the impact speed of the closing element or armature at the stop can advantageously be reduced by adjustable damping when opening and closing the solenoid valve. Switching noise and valve wear can thereby be reduced. The magnitude of the variably adjustable damping can be selected such that the switching valve can be operated as a "quasi-control valve" under a fluid flow which generates a hydraulic pressure having a destabilizing effect on the closing element. This means that an adjustable damping allows a variable selection of the opening or closing period of the switching valve.

In addition, in the embodiment of the method according to the invention for triggering an electromagnetic valve, armature position control is not required in the case of a switching valve. The switching valve does not have to have any stable working point. This means that the forces acting on the armature (for example magnetic forces, hydraulic forces and spring forces) which depend, among other physical variables, on the armature stroke do not necessarily have a working point at which the force balance is stable. The switching valve can be opened and closed very slowly and very quickly by adjustable damping. In the "quasi control valve" operating mode, it is not possible to maintain the partial stroke position with a constant stroke over a longer period of time.

Furthermore, the embodiment of the method according to the invention for triggering a solenoid valve can be combined with the armature position control of DE 10 2018 930 A1, which is disclosed later. The switching valve can thus be operated as a control valve. The stability of the armature position control loop is improved by electromagnetically adjustable armature damping. This applies in particular to higher fluid temperatures, since in this case the hydraulic viscous damping of the closing element or of the armature is reduced. By means of the proposed electromagnetic damping of the method for triggering a solenoid valve, a position-controlled solenoid valve of DE 10 2018 221 930 A1, which is disclosed subsequently, can have sufficient damping. In the "regulating valve" operating mode, the partial stroke position can be maintained with a constant stroke over a longer period of time.

Embodiments of the invention provide a method for triggering a solenoid valve comprising a magnet assembly with an electrical coil and a movably supported magnet armature with a closing element, which is moved in a direction of movement against the force of a return spring by triggering of the magnet assembly. In addition, the closing element rests sealingly in the valve seat in the closed state of the solenoid valve and, in the open state of the solenoid valve, is lifted off the valve seat and sets the effective opening cross section of the solenoid valve. In this case, at least one input variable which influences the armature movement or is influenced by the armature movement is detected. An armature stroke is estimated based on the detected at least one input variable, and at least one electromagnetic damping variable for affecting armature motion is calculated and output to the magnet assembly. In order to estimate the armature travel and to calculate at least one electromagnetic damping variable, at least one characteristic map or at least one mathematical function is used.

Furthermore, an evaluation and control unit is proposed, which is designed to carry out such a method for triggering a solenoid valve.

An evaluation and control unit is understood here to be an electrical device, such as a controller, in particular a brake controller, which processes or evaluates the detected sensor signals. The evaluation and control unit can have at least one interface which can be designed on the basis of hardware and/or software. In a hardware-based configuration, the interface can be, for example, a part of a so-called ASIC system that contains the various functions of the evaluation and control unit. It is also possible that the interface is a separate integrated circuit or is at least partly composed of discrete components. In a software-based configuration, the interface may be, for example, a software module that is present on the microcontroller together with other software modules. Also advantageous is a computer program product with a program code, which can be stored on a machine-readable carrier such as a semiconductor memory, a hard disk memory or an optical memory, and which is used to carry out the method for triggering the solenoid valve, in particular when the program is run by an evaluation and control unit.

The method for triggering a solenoid valve described above can be advantageously improved by the measures and improvements listed below.

It is particularly advantageous if the at least one input variable can be the coil current or the trigger voltage or the ohmic resistance of the coil.

In a further advantageous embodiment of the method, the at least one characteristic field can be a field characteristic describing the flux linkage as a function of the armature travel and the coil current, or a moving inductance characteristic field derived from a partial derivative of the flux linkage with respect to the armature travel, or a current inductance characteristic field derived from a partial derivative of the flux linkage with respect to the coil current. The armature travel can be determined, for example, as a function of the input variables coil current, trigger voltage and ohmic resistance of the coil and the characteristic field of the magnetic circuit, as described, for example, in DE 10 2018 930 A1 of the subsequent publication. The armature speed can be calculated, for example, by the time derivative of the armature travel. In addition, the electromagnetic damping variable may be calculated as a damping voltage that is superimposed on the trigger voltage of the solenoid valve and reduces or damps the armature speed.

In a further advantageous embodiment of the method, the first damping voltage can be calculated from the product of a first transfer function and the armature speed, wherein the first transfer function is calculated from a value resulting from a multiplication of a first motion inductance characteristic diagram and a first gain factor, by means of which the damping effect can be set. For calculating the electromagnetic damping variable, a family of characteristic curves can be used to describe the dynamic behavior of the armature reaction. For this purpose, for example, the above-mentioned family of characteristic curves of the motion inductance can be used, which can be stored in the evaluation and control unit. The characteristic field depends on the armature travel and the coil current and exhibits a gradient of the armature travel of the flux linkage. And obtaining the value of the motion inductance according to the current and the armature stroke. This value is multiplied by the armature speed and an adjustable first gain factor to derive a first damping voltage that is subtracted from the trigger voltage. The first damping voltage is proportional to the voltage induced by the motion inductance. The magnitude of the first damping voltage or the magnitude of the electromagnetic damping effect can be set by the magnitude of the first gain factor. For smaller armature strokes, the value of the first movement inductance is smaller and increases with increasing armature stroke. Thus, at a predetermined armature speed, for a larger armature travel, a larger second damping voltage will be achieved, and thus a larger damping action will be achieved than for a smaller travel. The armature travel and the coil current are used as input variables. These input variables must be measured or calculated. The armature speed is obtained from the time derivative of the armature travel. For example, DE 10 2018 221 930 A1, which is published below, discloses a method with which the armature travel can be determined from the measured variables, the trigger voltage, the coil current and the ohmic resistance of the coil, as well as the characteristic field of the magnetic circuit. Instead of the characteristic map of the motion inductance, other characteristic maps can also be used.

In a further advantageous embodiment of the method, the second damping voltage can be calculated from the product of a second transfer function and the armature speed, wherein the second transfer function is calculated from a value resulting from multiplication of a corresponding second series of motion inductance characteristic curves and a second gain factor, by means of which the damping action can be set. The value of the second movement inductance is greater when the armature stroke is smaller and decreases with increasing armature stroke. Thus, at a predetermined armature speed, for a smaller armature travel, a greater second damping voltage will be achieved, and thus a greater damping action will be achieved than for a larger travel. The reverse is true for the first damping voltage, which, due to the values of the first movement inductance and the armature speed, produces a greater damping effect at a greater armature travel than at a smaller armature travel. By combining the first damping voltage and the second damping voltage, the common damping effect can be better adapted to the armature stroke by a suitable selection of the respective gain factor.

In a further advantageous embodiment of the method, the third damping voltage can be calculated from the product of a third transfer function and a third gain factor, by means of which the damping action can be set, wherein the third transfer function is the inverse transfer function of the magnetic circuit of the magnet assembly. The third transfer function may add a first product of the current inductance and the armature acceleration to a second product of the ohmic resistance of the coil and the armature speed, wherein the current inductance may be obtained from a corresponding family of characteristics, and the armature acceleration may be calculated from a time derivative of the armature speed. A delayed damping action at the armature caused by the magnetic circuit can thereby be avoided. The main advantage is that the damping action at the armature no longer has a time delay, but the damping can act immediately, since the time delay of the magnetic circuit caused by the transfer function of the magnetic circuit will be compensated by the third transfer function achieved. In this way, the damping effect is improved compared to the other specified triggering methods. To trigger, the armature travel, armature speed, armature acceleration and armature current are detected, measured or calculated. Furthermore, the third gain factor may depend on the armature travel and the coil current.

Drawings

Embodiments of the invention are illustrated in the drawings and are explained in detail in the following description. In the drawings, the same reference numerals denote parts or elements performing the same or similar functions.

Fig. 1 shows a schematic cross-sectional view of an embodiment of a normally closed solenoid valve, which is triggered by the method according to the invention for triggering a solenoid valve.

Fig. 2 shows a schematic circuit diagram of an assembly with an evaluation and control unit and the solenoid valve of fig. 1.

FIG. 3 shows a schematic flow chart of an embodiment of a method for triggering a solenoid valve according to the present invention.

Fig. 4 shows a schematic block diagram of the action chain of the assembly in fig. 2 with a first embodiment of electromagnetic damping.

Fig. 5 shows a schematic block diagram of the action chain of the assembly in fig. 2 with a second embodiment of electromagnetic damping.

Fig. 6 shows a schematic block diagram of the action chain of the assembly in fig. 2 with a third embodiment of electromagnetic damping.

Fig. 7 shows a schematic characteristic diagram of the flux linkage of the solenoid valve in fig. 1 as a function of the working air gap and the coil current.

Fig. 8 shows a schematic characteristic diagram of the flux linkage of the solenoid valve from fig. 1 as a function of the armature travel and the coil current.

Fig. 9 shows a schematic first characteristic diagram of a kinematic inductance, which is derived from the characteristic diagram of the flux linkage of fig. 8.

Fig. 10 shows a schematic second characteristic diagram of the motion inductance, which is derived from the characteristic diagram of the flux linkage of fig. 7.

Fig. 11 shows characteristic diagrams of the actuation voltage, the armature travel, the armature speed and the coil current over time when the solenoid valve in fig. 1 is actuated without electromagnetic damping.

Fig. 12 shows characteristic diagrams of the actuation voltage, the armature travel, the armature speed and the coil current over time when the solenoid valve in fig. 1 is actuated with electromagnetic damping.

Detailed Description

As can be seen from fig. 1, the illustrated embodiment of the solenoid valve 1 comprises a magnet assembly 3 with an electrical coil 4 and a movably supported magnet armature 6 with a closing element 6.1, which magnet armature 6 is moved in the direction of movement against the force of a return spring 8 by triggering of the magnet assembly 3. In the closed state of the solenoid valve 1 shown, the closing element 6.1 rests sealingly in the valve seat 7.1. In the open state of the solenoid valve 1, which is not shown, the closing element 6.1 is lifted off the valve seat 7.1 and sets the effective opening cross section WQ of the solenoid valve 1.

As can also be seen from fig. 1, the solenoid valve 1 shown corresponds to a normally closed 2/2 solenoid valve, in which the ball cone seat is in the closed armature position. As can also be seen from fig. 2, the voltage uE acts on the magnet arrangement 3, so that a coil current J flows in the electrical coil 4, as a result of which a magnetic flux Ψ is established in the iron circuit and in the working air gap ALS. As can also be seen from fig. 1, in the working air gap ALS, the magnetic force Fm (x, J) acts on the magnet armature 6 against the spring force Ff (x) of the return spring 8. Thereby opening the solenoid valve 1. This means that the closing element 6.1 is lifted off the valve seat 7.1 and releases the effective opening cross section WQ at the ball cone seat. The magnetic force Fm (x, J) depends on the armature travel x or the working air gap ALS and the coil current J. The spring force Ff (x) depends on the armature travel x. If a volume flow q flows in the direction of the arrow in the solenoid valve 1 during the opening process, a hydraulic force Fh (x, p 12) acts on the magnet armature 6 in the closing direction. The hydraulic force Fh (x, p 12) depends on the armature travel x and on a pressure difference p12, which is the difference between a first pressure p1 on the inflow side of the solenoid valve 1 and a second pressure p2 on the outflow side of the solenoid valve 1. During the movement of the armature, a damping force Fd (v) acts, which is dependent on the armature speed v. Since this damping force Fd (v) always acts counter to the armature speed direction, the magnet armature 6 is braked. This means that the damping force Fd (v) acts downwards (Fd +) when the solenoid valve 1 is open and upwards (Fd-) when the solenoid valve 1 is closed. When the solenoid valve 1 is opened, the armature speed v increases and strikes a stop at a maximum impact speed, in this case the pole core 2. Due to the greater armature deceleration, a greater time-dependent pulse force acts on the stop or pole core 2. These forces can cause noise and wear at the pole core 2 or the magnet armature 6. Similarly, when the solenoid valve 1 is closed, noise and wear can occur in the valve seat 7.1 due to the impact of the closing element 6.1 in the valve seat 7.1.

As can also be seen from fig. 2, the electrical coil 4 comprises an ohmic resistance R and an inductance L (x, J) which is dependent on the armature travel x or the working air gap ALS. Equations (1) and (2) show the voltage balance of the illustrated components.

uE _(t) ＝u _ind +u _R (1)

Equations (1) and (2) indicate that the coil current J is determined by a predetermined input voltage uE (t) that varies with time, which is equal to the voltage drop uR across the ohmic resistance R and the induced voltage u across the inductance L (x, J) _ind The sum, which is equal to the time variation of the flux linkage Ψ (x, J). Equation 3 shows the temporal change of the flux linkage ψ (x, J).

The time variation of the flux linkage Ψ (x, J) is determined by the instantaneous current gradient and the current inductance

Product of (d) with armature velocity v and motion inductance

The sum of the products of (a) and (b) is determined. The current inductance and the motion inductance are functions of the armature travel x or the working air gap ALS and the coil current J.

As can also be seen from fig. 3, in the exemplary embodiment of the method 100 according to the invention for triggering the solenoid valve 1, at least one input variable influencing or influenced by the armature movement AB is detected in a step S100. Based on the detected at least one input variable, the armature travel x is estimated in step S110, and at least one electromagnetic damping variable affecting the armature movement AB is calculated in step S120. The electromagnetic damping variable is output to the magnet assembly 3 in step S130. In this case, at least one characteristic map or at least one mathematical function is used for estimating the armature travel x and for calculating at least one electromagnetic damping variable.

As can be seen from fig. 4 to 6, the dashed box describes the dynamic behavior of the magnetic circuit dynamics MKD as coil current J, which depends on the input voltage uE applied to the coil 4 and the armature travel x. The magnetic circuit dynamics MKD can be derived from the circuit of the magnetic circuit of fig. 2 by the laplace transform of equations (2) and (3). The first block describes the transfer characteristic of the magnetic circuit as a transfer function GM(s), which here corresponds to the PT1 characteristic. Equation (4) shows the transfer function GM(s).

Wherein the time constant τ = Ψ _J /R。

The output variable of the transfer function GM(s) of the magnetic circuit is the coil current J. In a further block representing the armature movement AB, the armature travel x is generated as an output variable from the input coil current J as an input variable. For the adjustable effective cross section WQ, in the corresponding block the armature travel x and the pressure difference p12 exerted on the solenoid valve 1 between the inflow side and the outflow side of the solenoid valve 1 are input as input variables. The differential pressure p12 and the armature travel x produce a volume flow q through the ball-cone valve seat. The reaction of the armature speed v via the motion inductance Ψ x generates an induced electromotive force uiB, which is subtracted from the predetermined input voltage uE (t). This process is referred to herein as an anchoring reaction. The resulting magnetic circuit voltage um is the input variable of the magnetic circuit transfer function GM(s). The induced electromotive force voltage uiB is determined as a transfer function GAB(s) of the armature reaction by the second block of the magnetic circuit dynamics MKD according to equation (5). In this case, the armature speed v or the time-dependent armature stroke x is input as an input variable into the transfer function GAB(s) of the armature reaction.

GAB(s)＝Ψ _x *s (4)

The induced electromotive force uiB is calculated according to equation (5).

uiB(s)＝GAB(s)*x(s) (5)

It can also be seen in fig. 4 to 6 that, in the exemplary embodiment shown, the evaluation and control units 10A, 10B, 10C, which are shown in dashed lines, each produce a damping action or an electromagnetic damping variable which influences the armature movement AB. The evaluation and control units 10A, 10B, 10C can be implemented, for example, as ASICs (application specific integrated circuits) for triggering the solenoid valves 1. As can also be seen from fig. 4 to 6, in the exemplary embodiment shown, the electromagnetic damping variables are calculated as damping voltages ud1, ud2, ud3, which are superimposed on the actuation voltage U of the solenoid valve and damp the armature movement AB or the armature speed v. For calculating the damping variable, a characteristic map is used in the exemplary embodiment shown, which describes the dynamic behavior of the armature reaction. Fig. 7 thus shows, for example, a characteristic diagram of the flux linkage Ψ (ALS, J) as a function of the working air gap ALS and of the coil current J of the solenoid valve 1 shown in fig. 1. Fig. 8 shows, for example, the flux linkage Ψ (x, J) as a function of the armature travel x and the coil current J of the solenoid valve 1 shown in fig. 1. The current inductance can be determined from the characteristic curves of the flux linkage Ψ (x, J) shown in fig. 7 and 8

And a moving inductor

The current inductance is derived from the partial derivative of the flux linkage Ψ (x, J) with respect to the coil current J, and the motion inductance is derived from the partial derivative of the linkage flux Ψ (x, J) with respect to the armature travel (x). Fig. 9 exemplarily shows the motion inductance Ψ _x A first family of characteristics of (x, J), which is calculated from the family of characteristics of the flux linkage Ψ (x, J) shown in fig. 8. Fig. 10 exemplarily shows the motion inductance Ψ _x (x _max -x, J), which is likewise calculated from the family of characteristic curves of the flux linkage Ψ (x, J) shown in fig. 8.

As can also be seen from fig. 4, the first block in the illustrated evaluation and control unit 10A represents the first transfer function G1(s) for generating the "electromagnetic damping". Here, the first transfer function G1(s) is determined by equation (7).

G1(s)＝k ₁ *Ψ _x (x，J) (7)

In order to calculate the "electromagnetic damping" using the first transfer function G1(s), the coil current J (t) is measured over time and the armature travel x (t) is determined over time from the other physical measurement variables. For this purpose, for example, the method disclosed in DE 10 2018 221 930 A1, which is published below, can be used, which determines the armature travel x from the measured variables, the trigger voltage U, the coil current J and the ohmic resistance R, and the characteristic field of the magnetic circuit. The armature speed v is calculated by the differential dx/dt of the armature travel x over time. In the transfer function of the laplace transform, the differential is the product of the armature travel x and the variable s. The calculated armature velocity v is then multiplied by a first gain factor k1 and by the motion inductance Ψ _x (x, J). The first damping voltage ud1 is then calculated using equation (8).

ud1(s)＝G1(s)*s*x(s)＝G1(s)*v(s) (8)

Thus, the first damping voltage ud1 is calculated from the product of the first transfer function G1(s) and the armature speed v. As can be seen from equations (7) and (8), the calculated armature speed v is compared with the corresponding first characteristic field of motion inductances Ψ from fig. 9 _x The value obtained in (x, J) is multiplied by a first gain factor k1 that can be used to adjust the damping action to calculate a first damping voltage ud1.

The calculated first damping voltage ud1 is then subtracted from the preset trigger voltage U. This means that the evaluation and control unit 10A applies the magnetic circuit by means of the movement inductance Ψ by means of the first transfer function G1(s) implemented _x Similar principles of armature reaction. The magnitude of the armature reaction can be set by a first factor k 1. The adjustable armature reaction has a similar effect to the hydraulic damping force which acts against the armature movement AB or the armature speed v and increases with increasing armature speed v. The first damping voltage ud1 superimposed on the predetermined trigger voltage U increases with increasing armature speed v. Thus, when the magnet armature 6 is stroked at a positive armature velocity vWhen on, the preset trigger voltage U is decreased by the first damping voltage ud1, and thus the coil current J is also decreased. As a result, a smaller magnetic force Fm acts on the opening magnet armature 6 than in the case of an activation without the first damping voltage ud1. This fact can be explained as follows: during the opening process, an opening magnetic force is exerted on the armature, which is generated by a coil current J, which is in turn generated by a predetermined trigger voltage U. At the same time, the first damping voltage ud1 causes a negative current, the magnetic force it generates braking of the armature 6. For this reason, the triggering shown is referred to as electromagnetic damping. However, the effect of the electromagnetic damping on the magnet armature 6 is delayed by the transfer characteristic of the magnetic circuit, described by the PT1 characteristic, according to the transfer function GM(s) of the magnetic circuit of the solenoid valve 1. When the magnet armature 6 closes with a negative armature speed v, the magnetic force generated by the first damping voltage ud1 acts against the spring force Ff of the return spring 8 and moves the armature or dampens the negative armature speed v.

The operating characteristics of the solenoid valve 1 shown in fig. 1 without or with electromagnetic damping are explained below with reference to fig. 11 and 12. Fig. 11 shows the preset trigger voltage U, the armature travel x, the armature speed v and the coil current J at time t with a conventional triggering of the solenoid valve 1 without electromagnetic damping, and fig. 12 shows the preset trigger voltage U, the armature travel x, the armature speed v and the coil current J at time t with a triggering of the solenoid valve 1 with electromagnetic damping according to the invention. As can be seen from fig. 11, the magnet armature 6 opens the solenoid valve 1 for a first time period Δ t1 of, for example, approximately 1.5ms, and closes the solenoid valve 1 for a second time period Δ t2 of, for example, approximately 1.1 ms. It can also be seen from fig. 11 that the magnet armature 6 strikes the stop or pole piece 2 when opening at a first impact velocity vm1 of, for example, 1.1 m/s. When closing, the closing element 6.1 connected to the magnet armature 6 strikes the valve seat at a second impact velocity vm2 of, for example, 1.2 m/s. It can also be seen from fig. 11 that the inductance Ψ for the movement is generated by the movement of the solenoid valve 1 during the opening phase _x (x, J) armature reaction, combined with armature velocity v, causes a current dip JEB. During the closing of the solenoid valve 1, the armature reaction causes the current to rise JAN.

As can also be seen from fig. 12, the preset trigger voltage U corresponds to the trigger voltage U in fig. 11. The first damping voltage ud1 is subtracted from the preset voltage U. A first damping voltage ud1 for the "electromagnetic damping" of the magnet armature 6 is generated by the evaluation and control unit 10A in fig. 4. The input voltage uE applied to the magnet assembly 3 is derived from the difference between the trigger voltage U and the first damping voltage ud1. It can also be seen from fig. 12 that the input voltage uE is significantly lower than the predetermined trigger voltage U when the solenoid valve 1 is open. This results in a larger current dip JEBD for a longer period of time compared to the conventional triggering in fig. 11. This means that the opening time Δ t1D of, for example, approximately 10ms is much longer than the opening time Δ t1 of the conventional trigger in fig. 11. Furthermore, the resulting first impact velocity vm1D of the magnet armature 6 against the stop or pole core 2 is significantly lower, for example 0.2m/s, than the conventionally triggered first impact velocity vm 1. When the solenoid valve 1 is closed, the coil current J has a greater current rise JAND for a longer period of time than the conventional triggering in fig. 11. As a result, the closing time Δ t1 is increased to approximately 9.8ms in comparison with the conventional triggering in fig. 11, and the impact speed vm2D of the closing element 6.1 connected to the magnet armature 6 is reduced to, for example, 0.1m/s.

The impact speed vm1D, vm D of the magnet armature 6 or of the closing element 6.1 can be significantly reduced by electromagnetic damping when the solenoid valve 1 opens and closes. Since the strength of the electromagnetic damping can be adjusted by the first gain factor k1, the opening and closing times are variable.

As can also be seen from fig. 5, the evaluation and control unit 10B shown differs from the evaluation and control unit 10A shown in fig. 4 by a second block which represents a second transfer function G2(s) for generating the "electromagnetic damping". Here, the second transfer function G2(s) is determined by equation (9).

G2(s)＝k ₂ *Ψ _x (x _max -x，J) (9)

In order to calculate the "electromagnetic damping" using the second transfer function G2(s), similarly to the first transfer function G1(s), the coil current J (t) is measured as a function of time, and the armature travel x (t) as a function of time is determined from the other physical measurement variables. Armature ironThe velocity v is calculated by the differential dx/dt of the armature travel x over time. The calculated armature velocity v is then multiplied by a second gain factor k2 and by the motion inductance Ψ _x (x _max -x, J). The second damping voltage ud2 is then calculated using equation (10).

ud2(s)＝G2(s)*s*x(s)＝G2(s)*v(s) (10)

The second damping voltage ud2 is thus calculated from the product of the second transfer function G2(s) and the armature speed v. As can be seen from equations (9) and (10), the calculated armature speed v is compared with the corresponding second characteristic field Ψ of the motion inductance, which is shown in fig. 10 _x (x _max -x, J) and a second gain factor k2 usable for adjusting the damping effect to calculate a second damping voltage ud2. In contrast to the evaluation and control unit in fig. 4, the evaluation and control unit 10B generates a second damping voltage ud2 in addition to the first damping voltage ud1. It can also be seen from fig. 10 that for the motion inductance Ψ _x (x _max -x, J), the value of the moving inductance Ψ x is greater at smaller armature strokes x and decreases with increasing armature strokes x. Thus, at a predefined armature speed v, a greater second damping voltage ud2 and thus a greater damping action will be achieved with a smaller armature stroke x than with a larger armature stroke. It can also be seen from fig. 9 that the opposite applies to the first damping voltage ud1, which is derived from the first series Ψ of the characteristic curves of the motion inductances _x (x, J) and armature velocity v. In this embodiment, the damping action can advantageously be better adapted to the armature travel x by a suitable choice of the respective gain factor k1, k 2.

As can also be seen from fig. 6, the evaluation and control unit 10C shown differs from the evaluation and control units 10A, 10B shown in fig. 4 and 5 by a third transfer function G3(s) for generating "electromagnetic damping" which is represented by a block. Here, the third transfer function G3(s) is determined by equation (11).

The third transfer function G3(s) is intended to avoid a delay in the damping action of the magnetic circuit on the magnet armature 6, which is represented by the PT1 characteristic of the transfer function GM(s). For this purpose, the third transfer function G3(s) is realized as the inverse transfer function of the transfer function GM(s) of the magnetic circuit. Similarly to the first transfer function G1(s) and the second transfer function G2(s), in order to calculate the "electromagnetic damping" using the third transfer function G3(s), the coil current J (t) is measured over time and the armature travel x (t) is determined over time from the other physical measurement variables. The armature speed v is calculated by the differential dx/dt of the armature travel x over time. The armature acceleration a is calculated by the differential dv/dt of the armature velocity v over time. The third damping voltage ud3 is then calculated using equations (12) and (13).

ud3(s)＝G3(s)*s*x(s) (12)

ud3(s)＝k3(x，J)*[Ψ _J (x，J)*s ² +R*s] (13)

The third damping voltage ud3 is the current inductance Ψ J (x, J) and the armature acceleration a(s) ² ) And the sum of the product of ohmic resistance R and armature speed v(s). The calculated sum is then multiplied by a third gain factor k3 (x, J), which in the illustrated embodiment also depends on the armature travel x and the coil current J. Similar to the first and second damping voltages ud1 and ud2, the third damping voltage ud3 is subtracted from the preset trigger voltage u. The main advantage of this embodiment is that the damping action at the magnet armature 6 no longer has a time delay, but acts immediately. The time delay of the magnetic circuit caused by the transfer function GM(s) of the magnetic circuit is compensated by a third transfer function G3(s) implemented as an inverse transfer function. As a result, the damping effect is improved compared to the other embodiments described.

The method 100 can be implemented, for example, in the evaluation and control unit 10 in software or hardware or in a hybrid form of software and hardware.

The embodiment of the method for triggering a solenoid valve according to the invention can be used for any hydraulic or pneumatic valve actuated by a magnetic circuit, without requiring hardware modifications to the valve.

Claims

1. A method (100) for triggering a solenoid valve (1) comprising a magnet assembly (3) having an electrical coil (4) and a movably supported magnet armature (6) having a closing element (6.1), the magnet armature (6) being moved in a movement direction counter to the force of a return spring (8) by triggering of the magnet assembly (3), wherein the closing element (6.1) rests sealingly in a valve seat (7.1) in a closed state of the solenoid valve (1) and, in an open state of the solenoid valve (1), lifts off from the valve seat (7.1) and adjusts an effective opening cross section (WQ) of the solenoid valve (1), wherein at least one input variable influencing an armature movement (AB) or being influenced by the armature movement (AB) is detected, wherein an armature travel (x) is estimated on the basis of the detected at least one input variable, and at least one electromagnetic damping variable for influencing the armature movement (AB) is calculated and output to the magnet assembly (3), wherein the at least one electromagnetic damping variable is calculated and the at least one mathematical stroke characteristic function (x) is used.

2. The method (100) according to claim 1, wherein the at least one input variable is a coil current (J) and/or a trigger voltage (U) and/or an ohmic resistance (R) of the coil (4).

3. The method (100) according to claim 1 or 2, wherein the at least one characteristic family is a family of characteristics describing a flux linkage (Ψ) as a function of the armature travel (x) and the coil current (J), or a motion inductance (Ψ) derived from a partial derivative of the flux linkage (Ψ (x, J)) with respect to the armature travel (x) _x (x,J)、Ψ _x (x _max -x, J)) or a current inductance (Ψ) derived from a partial derivative of the flux linkage (Ψ (x, J)) with respect to the coil current (J) _J (x, J)) of a family of characteristic curves.

4. A method (100) according to claim 3, wherein the armature stroke (x) is determined from the input variable coil current (J), a trigger voltage (U), an ohmic resistance (R) of the coil (4) and one or more characteristic fields of a magnetic circuit of the magnet assembly (3).

5. The method (100) according to claim 4, wherein the armature speed (v) is calculated by a time derivative of the armature stroke (x).

6. The method (100) according to claim 1 or 2, wherein the electromagnetic damping variable is calculated as a damping voltage (ud 1, ud2, ud 3) superimposed on a trigger voltage (U) of the solenoid valve and damping an armature velocity (v).

7. The method (100) according to claim 6, wherein the first damping voltage (ud 1) is calculated from the product of a first transfer function (G1 (s)) and the armature velocity (v), wherein the first damping voltage (ud 1) is calculated from a first family of motion inductance characteristics (Ψ) _x (x, J)) is multiplied by a first gain factor (k 1) that can be used to adjust the damping effect to calculate the first transfer function (G1 (s)).

8. Method (100) according to claim 6, wherein the second damping voltage (ud 2) is calculated from the product of a second transfer function (G2 (s)) and the armature velocity (v), wherein the second damping voltage (ud 2) is calculated from a second series of motion inductance characteristic curves (Ψ) _x (x _max -x, J)) and a second gain factor (k 2) usable for adjusting the damping effect by multiplying said second transfer function (G2 (s)).

9. The method (100) according to claim 6, wherein the third damping voltage (ud 3) is calculated from the product of a third transfer function (G3 (s)) and a third gain factor (k 3 (x, J)) that can be used to adjust the damping effect, wherein the third transfer function (G3 (s)) is the inverse transfer function (1/GM (s)) of the magnetic circuit of the magnet assembly (3).

10. According to claimThe method (100) of claim 9, wherein the third transfer function (G3 (s)) is a function of the current inductance (Ψ) _J (x, J)) and armature acceleration (a) is added to a second product of the ohmic resistance (R) of the coil (4) and the armature velocity (v), wherein the current inductance (Ψ) is _J (x, J)) are obtained from a corresponding family of characteristic curves, and the armature acceleration (a) is calculated from the time derivative of the armature speed (v).

11. The method (100) according to claim 9 or 10, wherein the third gain factor (k 3 (x, J)) is dependent on the armature stroke (x) and the coil current (J).

12. An evaluation and control unit (10) arranged to perform the method according to any one of claims 1 to 11.