EP1099043A1

EP1099043A1 - Method for controlling an electromagnetic valve drive mechanism for a gas exchange valve in an internal combustion piston engine

Info

Publication number: EP1099043A1
Application number: EP00935052A
Authority: EP
Inventors: Günter Schmitz; Christian Boie; Frank Van Der Staay; Lutz Kather
Original assignee: FEV Motorentechnik GmbH and Co KG
Current assignee: FEV Europe GmbH
Priority date: 1999-05-19
Filing date: 2000-05-17
Publication date: 2001-05-16
Anticipated expiration: 2020-05-17
Also published as: DE10081384D2; WO2000071861A1; JP2003500587A; EP1099043B1; ATE306013T1; DE50011289D1; US6474276B1

Abstract

A method for controlling an electromagnetic actuator for a cylinder valve in a piston-type internal combustion engine with the actuator being operatively connected to the cylinder valve and moveable back and forth between two electromagnetics, counter to the force of at least one restoring spring. The current supplied to the electromagnetics is controlled with the aid of a sensor arrangement and via an engine control unit such that the current supply to the catching electromagnet, i.e., the electromagnet being approached by the moveable armature of the actuator, is controlled so as to move the armature slowly toward the respective pole face. Moreover, in order to regulate the valve play during the closing movement of a cylinder valve, the current supply to the catching electromagnet is controlled such that the valve initially touches down softly on its seat and that following the valve play, the armature touches down softly on the pole face.

Description

Name: Method for controlling an electromagnetic valve train for a gas exchange valve on a piston internal combustion engine

In the case of electromagnetic valve drives for actuating a gas exchange valve on a piston internal combustion engine, there is a major problem, particularly in the presence of valve clearance, in regulating the speed at which the valve touches down to very small values (below 0.2 m / s), since the impact point of the valve in the Operation changes for thermal reasons (variation of the valve clearance). In addition, the armature must still safely reach the pole face after the valve strikes. If the current is too low, the armature reverses early and knocks the valve loose. If the current is too high, the armature touch-up speeds are high, which is acoustically problematic on the one hand, but on the other hand also leads to bouncing processes and, in the worst case, also to renewed, uncontrolled valve openings and thus to failure of the entire system.

The invention is explained in more detail with reference to schematic drawings. Show it:

Fig. 1 with an electromagnetic valve train

control

Fig. 2 shows the course of the speed of the valve and armature during the closing movement

Fig. 3 shows the course of the speed of the valve and armature on reaching the closed position on a larger scale

Fig. 4 shows the course of the path of the valve and armature and the current as a function of time in a control according to the prior art technology

Fig. 5 shows the course of the speed of the valve and armature during the closing movement in a control according to the inventive method

Fig. The course of the path of the armature and the current as a function of time when using the inventive method

Fig. 7 shows the basic structure of the control in the form of a block diagram

8 shows the sequence of the control method according to the invention on the basis of a block diagram

9 the block diagram according to FIG. 8 supplemented by an "observer"

10 shows the block diagram according to FIG. 9 with a link between motor control and observer

FIG. 11 shows the block diagram according to FIG. 10 supplemented by a pre-estimation unit

12 and 12.1 modifications of the circuit when using an "observer"

Fig. 12 to 15 construction and function of a magnetoresistive motion sensor

16 and 17 embodiments of microwave resonator displacement sensors 18 shows an optical variant of a resonator displacement sensor

In Fig. 1, the basic principle of such an electromagnetic valve train with its control is shown schematically.

An electromagnetic valve train for actuating a gas exchange valve 2 consists essentially of an actuator 1 with a closing magnet 3 and an opening magnet 4, which are arranged at a distance from one another and between which an armature 5 against the force of return springs, namely an opening spring 7 and one Closing spring 8 is guided to move back and forth.

In Fig. 1 the "classic" arrangement of the opening spring and the closing spring is shown in the closed position. In this arrangement, the closing spring 8 acts directly via a spring plate 2.2 connected to the shaft 2.1 of the gas exchange valve 2. The guide rod 11 of the electromagnetic

Actuator is separated from the shaft 2.1, as a rule there is a gap in the closed position in the form of the so-called valve clearance VS. The opening spring 7 is in turn supported on a spring plate 11.1 on the guide rod 11, so that the guide rod 11 is supported on the stem 2.1 of the gas exchange valve 2 in the middle position when the magnets are de-energized under the opposing effect of the opening spring 7 and closing spring 8. Instead of the opening spring 7, it is also possible to provide only a single restoring spring which is designed such that it builds up a corresponding restoring force each time the armature 5 swings over the central position. A separate closing spring 8 is therefore omitted. In such an arrangement, however, the guide rod 11 must be connected to the shaft 2.1 of the gas exchange valve via a corresponding coupling element, which in the same way prevents the armature from moving back and forth transmits the gas exchange valve 2, although permits valve clearance.

The electromagnets 3 and 4 of the actuator 1 are controlled via an electronic motor control 9 in accordance with the specified control programs and depending on the operating data supplied to the motor control, such as speed, temperature, etc.

A sensor 10 is assigned to the actuator 1, which enables the detection of the actuator functions. The sensor 10 is shown schematically here. Depending on the design of the sensor, the path of the armature 5 can be detected, for example, so that the respective armature position of the motor control 9 can be transmitted. The armature speed can then optionally also be determined in the motor controller 9 by means of corresponding arithmetic operations, so that the energization of the two electromagnets 3, 4 can be controlled as a function of the armature position and / or as a function of the armature speed.

The sensor 10 does not necessarily have to be laterally assigned to the extended guide rod 11, as shown, but it is also possible to arrange corresponding sensors in the region of the pole face of the respective electromagnet or to assign it laterally to the armature 5.

The motor controller 9 also has corresponding means for detecting the current and the voltage for the respective electromagnet 3 and 4 and for changing the current profile and the voltage profile. The actuator 1 of the gas exchange valve 2 can then be controlled in a fully variable manner as a function of predefinable operating programs, possibly based on corresponding characteristic diagrams, for example with regard to the start and end of the

Opening hours. Also a control with regard to the height the opening stroke or the number of opening strokes during a closing time is possible.

In order to achieve low landing speeds of the armature 5, a current control is required which, as an input signal, requires information about the current movement or position of the armature. As long as there is no valve clearance, regulation based on the anchor position is sufficient. However, if there is a valve clearance on the closer side, the situation is quite problematic. The speed of the armature and thus of the valve must already be a very small value of approx. 0.2 m / s or less when the valve is placed in the valve seat (at least in the range of low speeds).

In Fig. 2 the situation for a "normal" valve dropping, i. H. without using the method according to the invention. The solid line shows the speed of the anchor over the anchor path. The position for the opened case is shown on the far right. An anchor stroke of 8mm was chosen as an example. The leftmost position at 0.0 shows the armature position when it contacts the pole face of the make magnet. A closing movement accordingly starts at the position on the far right in the picture at 8mm and speed 0. The speed now increases until the middle between the pole faces is reached (at approx. 4mm). If the armature is operated "normally" (uncontrolled), the valve still has a very high speed of about 1.1 m / s, especially when there is a clear valve clearance of, for example, 0.4 mm (cold OMotor) on arrival in the valve seat. This position separates the armature movement from the valve movement. The valve is braked abruptly (broken line), the speed even goes below zero, i.e. the valve bounces off again.

The Ankex slows down at first, but shortly before it hits, its speed increases again and it hits with it at a speed of approx. 0.5 m / s. The anchor speed had meanwhile been reduced to almost zero; if the capture current level were reduced further, the armature would reverse before reaching the pole face, and the system would fail.

In Fig. 3 the area of valve placement and armature placement is shown enlarged. The separate movements of the armature and valve can be clearly seen. First, armature and valve move together without valve play (curve part v _{A + v} ). As soon as the valve hits its seat, the valve and armature separate and carry out their own movements due to the valve play. (Valve broken line, armature solid line).

4 shows the courses of the anchor position (solid line), the valve position (broken line) and the current (dash-dotted line) over time. In the current level, one can first see that a constant current value is maintained, which, however, initially drops when the armature comes very close, since the counter-induced voltage exceeds the supply voltage. The current specification for the current level is then increased in order to catch the armature safely. Because the anchor almost comes to rest, the new level can also be reached, since no further counter-tension is initially induced by the immobility of the anchor.

5 and 6 show the relationships when using the method according to the invention for the exemplary embodiment according to FIGS. 2 and 4. 5 again shows the course of the speed over the anchor path. The course of the anchor speed differs significantly from the unregulated course. First, the armature is accelerated more after disconnection from the valve than in the uncontrolled / uncontrolled case. With a strong approach, however, the current is drastically reduced again to the level required to hold the anchor (here in the example approx. 1, 5A).

If the armature and yoke are designed accordingly, counter-current flow (reversing the current direction) can even be useful in order to generate repulsive forces.

6 shows the courses of anchor path and current over time. A valve impact speed of around 0.2 m / s can be achieved by regulating the current flow.

7 shows a block diagram of the actuation of the actuator. The motor controller 9 specifies the point in time when the movement process (valve closing) is initiated. This is done by switching off the current through the make coil in the current driver 12 (no power supply to the make coil is shown here). Depending on the respective armature position, which is controlled by a position detection device 13, for example sensor 10 plus processing circuit, the current is now regulated, for example, in such a way that the armature maintains a predefinable travel-speed profile, if possible.

In Fig. 8 it is now shown that two regulating or control processes are provided. First, during the flight of the gas exchange valve, the control is taken over by the block now referred to here as valve position controller 14. This block can be designed identically to that block 14 in FIG. 7, but must take into account that the target which can be reached at low speed does not represent the pole face but rather the valve seat, that is to say the position of the pole face plus valve clearance.

As soon as it is recognized that the valve has arrived in the seat (or is at least in the immediate vicinity), the armature control is switched over. This is shown in FIG. This is illustrated by the fact that a "valve separation detector" 17 determines that the valve has arrived in the seat and thus switches the current specification for the current driver 12 to the output of the armature position controller 15 The valve separation detector can obtain its information from the sensor 10 of the position detector or the output signal of the position detection 13, deduce the separation of the valve and armature from the current and / or voltage curve on the magnet or determine it via a separate sensor 16 . Such a sensor can simply consist of a contact that is closed when the two electrically conductive parts separate (eg anchor bolt and valve stem). In order to avoid problems with contamination of the contacts, however, a change in capacitance between the separating components can also be determined; this requires a non-conductive separating layer between the two components.

The armature current regulator can also function via a

Carry out time control since only the distance of the valve clearance still has to be bridged. For this purpose, the current curve is specified over time, for example, depending on the existing valve clearance. It is therefore also possible to use a valve position sensor instead of the armature position sensor, since the information about the armature position is no longer so important.

FIG. 9 shows an expansion of the control system, which is particularly useful if the position is to be detected using inexpensive sensors. This is because there is the problem that the path signal must be differentiated in order to obtain speed information. However, this is only very inadequately possible with a noisy or disturbed signal. Remedial action can now be taken with an observer 19 which contains a model of the actuator (for example in the form of differential equations for the relationship between see acceleration, speed and position of the armature as well as information about mass of armature and valve, spring forces etc.). After all, the possible course of the speed in principle by the system is predictable within limits. The model can now be initialized at the start of the movement. The exact position and the speed are known at this time. The new information about the measured position 13 and possibly the state variables determined by the model flow into the observer (into the model) as new input variables and can in turn be used to correct the currently output variables via path and speed. The model contained in the observer can also be self-calibrated (adapted). If, for example, the observer determines that the friction is greater than previously provided in the model, the corresponding size can be automatically re-parameterized.

Certain parameters can also be used by the engine control system to improve the model parameters, e.g. depending on the load (gas forces at the exhaust valve) or the engine temperature (estimate valve clearance, friction etc.) are fed into the model (see also Fig. 10, connection from 11 to 19).

In addition to the purely mechanical modeling, the magnetic forces can of course also be taken into account. For this purpose, knowledge of the current current supply must be available. This is shown in Figure 6 (connection from 12 to 19 in Fig. 10).

The quality of the controller itself can also be improved if one can make a forward-looking estimate of the influence the measures introduced (change in the current level) will have on the armature. According to 11 provides the controller 14 with a "pre-estimation unit", a predictor 20. This predictor 20 also contains again a model of the system and can therefore estimate the effects of the measures. If the measures are considered insufficient or too strong, the controller can be corrected accordingly ("reverted").

The predictor 20 can also be designed to be “learnable” so that it automatically adapts to changed model parameters.

Particular attention must be paid to the position of the armature or the valve, on the one hand, which is to be designed economically and, on the other hand, is as accurate as possible. Especially in the phase of the last approximation, when the speed is already relatively low and the path information has to be very precise, the resolution limit of a possibly required analog / digital conversion (quantization) can be problematic. This resolution can be improved by converting the currently estimated value of the position (e.g. from observer 19) from that of before the conversion

Sensor value is subtracted before the value is digitized. The return 21 of the position signal from the observer 19 into the position detection 13 can be seen in FIG.

An embodiment of the position detection is shown as an example in FIG. 12.1. The feedback signal 21, which is provided digitally by the observer, is fed to a D / A converter 22. The output of the D / A converter 22 thus delivers the value for the position currently determined by the observer in analog form. This value is subtracted with the aid of a subtractor 24 from the signal of a position sensor, which was first raised to the correct level by a processing circuit 23. Behind the subtractor there is only the difference to the position currently determined by the observer. The signal range of this signal is naturally much smaller than that of the original Chen position signal. It can thus be raised in level with the aid of an amplifier 25 before the A / D conversion 26. The A / D converter then feeds the difference signal between the ascertained by the observer and the current, new path information to the observer 19 again in digital form. If necessary, the latter can obtain the new position information by adding the previously determined signal 21 and the new difference information.

Other embodiments are also possible. For example, the A / D converter and / or the D / A converter can be integrated in the observer. (Fig.12.1)

According to the invention, the position and / or the speed of the armature is continuously measured with the aid of a sensor in order to control a gentle impact and is used for closed-loop control of the actuator. The invention is based on the fact that an effective closed-loop control of the armature or valve speed is only possible in the last part of the movement, ie shortly before reaching the respective end position, due to the dynamic properties of the system. Nevertheless, it is necessary to intervene at an earlier point in time in order to be able to reach the required current level at all. In the first part of the movement, the invention provides for the determination of parameters which are correlated with the cylinder internal pressure. This is done using the least squares method by considering the trajectory v (s) in the state space (v = speed, s = position). Depending on the size of the parameters, the voltage is switched on constantly when a certain path position s _{x is} reached. When the equilibrium of forces is reached (dv / dt = 0), a non-linear controller is preferably activated, which switches the voltage on or off as a function of the deviation (v - v (s)) of the measured speed from a desired curve v (s). According to the invention, when the voltage is switched off via a bridge circuit, energy is fed back into the electrical system with little loss, ie the respective one Coil operated with the supply voltage. Due to the resulting speed of the current drop when switching off, a closed-loop control according to the invention is possible particularly effectively.

In a preferred arrangement, the condition dv / dt = 0 is recognized directly by deriving and filtering the path signal.

In a further preferred arrangement, the condition dv / dt = 0 is replaced by the condition I> = I _max , ie the voltage is switched off and the regulator is activated when a predetermined current level I _{max is reached} .

In a preferred arrangement, the switch-on position s _on and the current threshold I _{max are expressed} as a function of the measured supply voltage and the parameters which reflect the internal cylinder pressure. This can be done by a functional relationship or a map.

In a preferred arrangement, the desired curve v (s) is chosen to be flat in the last part of the movement, so that the control can ensure a low touchdown speed even in the event of sensor errors.

In a preferred arrangement, the target curve v (s) runs at speeds less than 0.3 m / s, since in this case the response time of the control is short enough compared to the dead time of the system in order to implement a closed-loop control.

In a preferred arrangement, the flat target curve is expanded so far that the area of the valve clearance can be bridged so that the valve and armature touch down at low speed.

In a preferred arrangement, the valve clearance is measured in the first part of the opening phase of the valve by the abrupt drop in the speed of the armature upon impact with the valve is detected. The extent of the slow movement section can thus be adapted to the current valve clearance.

In a preferred arrangement, the spring-mass system is designed so that the distance from the point at which the force equilibrium is reached as early as possible to the end position on the opener and closer side is large enough to bridge the valve clearance and to compensate for sensor errors. A low eddy current armature, for example made of a sintered material, is preferably used in order to increase the scope by lowering the maximum required current level for the balance of forces.

To increase the travel range of low speed before the end position, the detachment process is designed by briefly energizing the holding magnet in such a way that a lower maximum speed is reached and the waypoint at which a force equilibrium can be reached at the earliest is further away from the end position. In a preferred arrangement, the mechanically withdrawn energy is fed back electrically by using a low-eddy current armature and a corresponding clocking stage, preferably in a bridge circuit.

In a preferred arrangement, a digital displacement sensor is used for the sensor.

In a preferred embodiment, the sensor

Raw signals are processed with the aid of a status observer so that the quality of the displacement, speed and current signals is improved by using information about the system behavior of the actuator. In a particularly preferred arrangement, the condition observer uses the parameters obtained with the back pressure in the initial phase of the movement, ie when the armature is detached, by measurement are correlated. In a particularly preferred arrangement, the sensor signal is averaged during the phase of the armature being in contact with one of the two end positions with the aim of compensating for any offset error and / or amplification error of the sensor and thus reducing the demands on the sensor with regard to temperature stability .

In a particularly preferred arrangement, the controller consists of a two- or three-point controller with a feedback branch, which contains a digital filter. This filter is preferably a low-pass filter with a suitably matched characteristic. The sampling time of the entire arrangement is preferably 20 μs.

In a particularly preferred arrangement, the output stage is a switching output stage with rise and fall times of less than 5 μs.

In a preferred arrangement there is communication between the impact control of the actuator and the driving engine control in such a way that the engine control provides information about the expected internal cylinder pressure, which is used in addition to the parameters determined by measurement, which are correlated with the actual internal cylinder pressure become. Furthermore, the impact control returns information to the engine control, such as measured valve clearance, further parameters which are correlated with the actual internal cylinder pressure, further parameters which are correlated with the wear of the actuator, furthermore parameters which correlate with the temperature of the actuator are.

In another preferred embodiment, the invention is used in the presence of a hydraulic valve lash adjuster. The fact that vibrations in the speed-path course, which at Impact of the anchor bolt on the valve in the presence of valve clearance normally occur and make it difficult to determine parameters that are correlated with the back pressure, here they are strongly damped.

When regulating actuators, in particular for carrying out the method according to the invention, high demands are placed on the quality of information. The requirements for resolution, reproducibility and accuracy are above what conventional analog sensors can achieve in this area of application today. One of the reasons for this is that the concentration, electrical interference fields in the immediate vicinity of the motor is immense and the interference levels coupled into the cables are very high.

For this reason, digital signal transmission is a possible solution to achieve the desired quality.

Another advantage is achieved if the measurement signal is obtained directly from a digital measurement process. The advantages are: no A / D conversion, inexpensive robust electronics, etc.

Some of the principles presented are based on digital measurement methods. A digital pulse or a binary bit pattern is output for each route. When determining the relative position, the absolute position must be derived using an algorithm, taking into account the rest position and the maximum anchor travel. The speed can be determined from the time difference between the pulses or bit pattern changes.

Preferred measuring methods are those that can be implemented as an integrated component including signal processing.

Digital methods for a relative position measurement: - Optical process with slotted disc

optical methods based on the interferometer principle, as described below,

magnetic methods with magnetoresistive matrix without binary coding, as described below,

- resonator measuring principles (frequency depending on the geometric position of the anchor path), as described below,

Absolute measuring methods that logically output a binary code corresponding to the position:

- optical processes with e.g. CCD line,

- Magnetic methods with a magnetoresistive matrix, one or two-dimensional structure, in contrast to singular magnetoresistive sensors, as previously known.

A path measurement using a magnetoresistive measuring principle based on measuring cell matrices is shown and described with reference to FIGS. 13 to 17. The magnetoresistive matrix 30 (XMR matrix) can be arranged, as can be seen in FIGS. 13 and 14. A position magnet 31 is attached to the guide rod 11. The evaluation circuit for the XMR matrix 30 outputs which sensor of the matrix of the sensor line receives a maximum signal. This is the position with which the position magnet 31 is correlated on the guide rod 11, i. H. the current path position.

A further embodiment is shown in FIG. 14. The signal processing is limited to the generation of pulses when the maximum changes from one individual sensor to the next. A preferred embodiment is the generation of a pulse code shifted by 90 ° for direction detection. To increase the resolution, a version with a special magnet geometry is suitable, e.g. For example, the embodiment in Fig. 15. The arrangement of two position magnets 30.1 and 30.2 in the middle creates a narrow area with horizontally running field lines created, which allows a larger distance between the matrix and the position magnet.

Another way to increase the resolution is to use the vernier principle. For this purpose, several position magnets are mounted on the guide rod 11.

Compensation for mechanical tolerances with regard to the rotation geometry of the guide rod is possible by evaluating the level distribution.

To further increase the accuracy, the use of two matrices in a special arrangement to one another is conceivable, for example opposite one another, to compensate for mechanical tolerances.

A path and speed measurement using a microwave resonator measuring principle is shown and described with reference to FIGS. 16 to 18.

16 shows an arrangement that can be placed on top of an actuator. The valve stem is non-positively connected to the EMC armature and the guide rod 11, so that the guide rod 11 reflects the position of the anchor plate.

The free end of the guide rod 11 protrudes into a resonator housing 35 which is partially, preferably in the areas which the guide rod does not reach during its linear movement, filled with a dielectric 36. An oscillator 37 is coupled to the resonator via a coupling device 38 (capacitive or inductive). This arrangement allows the armature path to be used as a frequency-determining component of an oscillator 37. Via a reference oscillator 38, in a mixer or a frequency demodulator 39 with subsequent filtering and signal processing 40, both the path signal 41 and the speed input formation 42 of the motor control are made available.

17 shows a comparable arrangement which can also be placed on top of an actuator. The guide rod 11 indicates the path position of the anchor plate. The guide rod 11 forms a displaceable part of a coaxial resonator 35, the fixed part of which is filled with a dielectric. The guide rod 11 can travel the linear path and thus change the reflection properties of such a coaxial resonator arrangement as a function of the EMC armature movement.

The oscillator 37 is coupled to the fixed resonator part between the center conductor 44 and the housing via an insulation 43. Via a reference oscillator 38, both path signal 41 and speed information 42 can be made available in a mixer or a frequency demodulator 39 with subsequent filtering and signal processing.

A distance and speed measurement using an optical resonator dimension principle is shown and described with reference to FIG. 21.

18 shows an arrangement in which an optical variant of a resonator measuring principle is shown, which can also be attached to the guide rod 11 of an actuator.

The guide rod 11 indicates the path position of the anchor plate. A magnetic arrangement 45, which effects the effect of the magnetic field on the zone 46, is connected to the shaft in order to convey the anchor position. The component 46 represents an optical conductor, the optical properties, preferably the refractive index, of which are a function of the magnetic field strength. The entire arrangement is shielded against interference and external fields. The optical conductor 46 is sealed on one side by an optical mirror 47 and is connected to semiconductor fiber via coupling elements 48, for example a glass fiber and / or a polarization-rotating element and / or an optical impedance matching, which is controlled via current signal 50 and driver 51 . An HL laser 49 emits a beam in the direction of the sensor 52, on which the second beam of the HL laser 49 also interferes via element 48, 46, 47, 46, 48, 49. The detector signal 53 thus measures interference due to path length changes in the two beam paths. A path length is now implicitly changed by means of magnetic field by magnet 45 by varying the refractive index in element 46 and thus forms a measure for the path of the guide rod 11. Another possibility for changing the length of element 46 when using optical materials whose refractive index is not The function of the magnetic field strength is obtained by gluing magnetostrictive material 46.1 to the optical element 46, so that a mechanical length change of element 46 occurs due to the magnetic field.

A path and speed signal is to be determined by evaluating the detector signal.

Claims

Expectations

1. Method for controlling an electromagnetic actuator for actuating a gas exchange valve on a piston internal combustion engine, which has an actuator which is operatively connected to the gas exchange valve and which is guided back and forth between two electromagnets against the force of at least one return spring, the energization of which is carried out with the aid a sensor system is controlled via a motor control system so that the energization of the capturing magnet is controlled in such a way that the armature is "creeped" towards the pole face.

2. The method according to claim 1, characterized in that for regulating a valve clearance during the closing movement of the

Gas exchange valve, the energization of the capturing magnet is controlled so that first the valve is seated gently and after passing through the valve clearance the armature on the pole face.

3. The method according to any one of claim 1 or 2, characterized in that depending on a position detection of the armature and / or the valve is controlled so that the armature adheres to a predetermined path-speed profile.

4. The method according to any one of claims 1 to 3, characterized in that in particular in the presence of a valve clearance when the valve strikes its seat, the flow of the catching magnet is switched to "armature control" and the armature is brought separately to the pole face.

5. The method according to claim 4, characterized in that the impact of the valve on its seat is detected via a valve separating detector.

6. The method according to any one of claims 1 to 5, characterized in that the energization of the electromagnet for guiding the armature takes place over a predeterminable time after the valve strikes its seat as a function of the given valve clearance.

7. The method according to any one of claims 1 to 6, characterized in that the position detection of the valve and / or armature following by sensors takes place via an electronic model of the actuator, which contains the functionally essential parameters of the actuator.

8. The method according to any one of claims 1 to 7, characterized in that to improve the model parameterization in the electronic model current operating data are applied from the engine control.

9. The method according to any one of claims 1 to 8, characterized in that the control measures initiated in each case via a containing an electronic model of the actuator

Preliminary estimate unit are checked with regard to their future effects and the controller is corrected if necessary.

10. The method according to any one of claims 1 to 9, characterized in that at the beginning of the movement of the gas exchange valve, the parameters are determined which are correlated with the cylinder internal pressure.

11. The method according to any one of claims 1 to 10, characterized in that energy is fed back into the vehicle electrical system via a bridge circuit when the voltage applied to the capturing electromagnet is switched off.

12. The method according to any one of claims 1 to 11, characterized in that each time the valve opening in the first part of the opening phase, the valve clearance in particular on the Er- Detection of the speed drop of the armature when it hits the valve is detected.

13. The method according to any one of claims 1 to 12, characterized in that the spring mass system formed by the actuator, the return spring and the gas exchange valve is designed so that the distance from the point of reaching the equilibrium of forces as soon as possible to the end position on the Is large enough to bridge the valve clearance and compensate for sensor errors.

14. The method according to any one of claims 1 to 13, characterized in that information about the movement of the gas exchange valve of the engine control system is supplied via the impact control.

15. The method according to any one of claims 1 to 14, characterized in that digital signals are generated to detect the path and / or speed of the armature and are made available to the motor control.