EP1630363B1 - Method to determine the phase of a camshaft in an internal combustion engine - Google Patents

Abstract

The method is for the determining of the rotational angular position of the camshaft (11) of a reciprocating piston engine in relation to the crankshaft (12). An assessed value is extrapolated for the rotational angle from at least two adjusting shaft rotational angle measurements, the time difference between the adjusting shaft measurement time points, and the interval between the last measurement time point and reference time point, and from this assessed value, the crankshaft rotational angle measured value, and the transmission characteristic, the value of the rotational angular position is determined magnetically.

Description

The invention relates to a method for determining the rotational angle position of the camshaft of a reciprocating internal combustion engine relative to the crankshaft, wherein the crankshaft via a variable speed drive with the camshaft is in drive connection, which is designed as a three-shaft gear with a crankshaft fixed drive shaft, a camshaft fixed output shaft and an adjusting that is in driving connection with an adjusting motor, wherein for at least one crankshaft measuring time a measured value for the crankshaft rotation angle is detected, wherein for at least two Verstellwellen measuring times each measured value for the Verstellwellenendrehwinkel digitally detected, wherein for at least one reference time, the crankshaft and Verstellwellen-measuring times is based on at least one crankshaft rotation angle measurement, at least one Verstellwellenendrehwinkel measured value and a transmission characteristic of the three-shaft transmission, a value for the Dr ehwinkellage the camshaft is determined relative to the crankshaft.

Such a method is known in practice. See eg DE 103 15 317 A1 , In this case, an epicyclic gear is provided as adjusting, with the drive shaft rotatably connected to a camshaft rotatably mounted relative to the camshaft gear, which is in driving connection via a drive chain with a crankshaft gear. An output shaft of the variable speed drive is in drive connection with the camshaft and an adjusting shaft with an adjusting motor. When the drive shaft is stationary, there is a gear ratio predetermined by the adjusting gear between the adjusting shaft and the output shaft, the so-called stationary gear ratio. When the adjusting rotates, increases or decreases depending on the direction of rotation of the adjusting relative to the camshaft gear, the gear ratio between the input and the output shaft, whereby the phase angle of the camshaft relative to the crankshaft changes. Compared to a method in which the internal combustion engine is operated with a constant phase position, by adjusting the phase position better cylinder filling of the internal combustion engine can be achieved, whereby fuel can be saved, the pollutant emissions can be reduced and / or the output line of the internal combustion engine can be increased. In order to control the phase position to a setpoint signal, the rotational angle of the crankshaft and the adjusting shaft are first measured by means of inductive sensors and then using the known stationary gear ratio, an actual value signal for the phase angle of the camshaft is determined relative to the crankshaft. At a reference time, an interrupt is triggered in a microprocessor-based electronic control unit, in which the measured value for the Verstellwellenendrehwinkel is read into a control device and compared with a provided setpoint signal. When a deviation between the measured value and the setpoint signal occurs, the control device controls the EC motor in such a way that the deviation is reduced. The measurement of the Verstellwellenendrehwinkels using magnetic field sensors, which detect the position of arranged on the circumference of the EC motor rotor magnet segments digitally. However, due to the digitization of the measured values and the reference time deviating from the adjusting shaft measuring instants, there are measurement inaccuracies which cause the measured relative rotational position of the camshaft to make a sawtooth-shaped oscillation around the actual angular position. This adversely affects the control accuracy and also has an increased energy consumption of the EC motor result.

It is therefore an object to provide a method of the type mentioned above, which allows an accurate determination of the angular position of the camshaft relative to the crankshaft.

This object is achieved by extrapolating from at least two Verstellwellenendrehwinkel measured values, the time difference between the Verstellwellen-measuring times and the time interval between the last Verstellwellen-measuring time and the reference time for the angle of rotation, which has the adjusting shaft at the reference time, and that the value for the rotational angular position is determined on the basis of the estimated value, the at least one crankshaft rotational angle measured value and the transmission characteristic.

Advantageously, therefore, the accuracy of the values for the phase angle is increased by the fact that the angle by which the adjusting shaft has rotated further between the last adjusting shaft measuring time and the respective current reference time is estimated and taken into account in the determination of the values for the phase position , The amplitude of the sawtooth-shaped oscillation, which executes the measured Verstellwellenendrehwinkelverlauf to the actual Verstellwellenendrehwinkelverlauf, thereby reduced accordingly. The inventive method thus enables a high precision in the determination of the phase position and a low power consumption of the adjusting motor.

In a preferred embodiment of the invention, a value for the angular velocity of the adjusting shaft is determined at least for the respectively last adjusting shaft measuring time, wherein the estimated value for the rotational angle which the adjusting shaft has at the reference time consists of the last adjusting shaft rotational angle measured value, the time difference between the Reference time and the last Verstellwellen measuring time and the angular velocity value is determined. The Verstellwellenendrehwinkel measured value at the reference time is thus determined by linear interpolation from the last Verstellwellenendrehwinkel measured value using the angular velocity value. The angular velocity value can be calculated from the angular difference of the last two measured angular velocity values and the time difference between the measuring instants associated with these angular velocity values.

In an advantageous embodiment of the invention, the adjusting motor is an EC motor having a stator with a winding and a rotatably connected to the adjusting rotor, are arranged on the circumferentially offset from each other, magnetized in opposite directions magnetized magnet segments, the tolerances with respect to their positioning and / or their dimensions, wherein the position of the magnet segments relative to the stator is detected for detecting the Verstellwellenendrehwinkel measured values and / or the angular velocity values, wherein at least one correction value for compensating the influence of at least one tolerance on the Verstellwellenendrehwinkel measured values detected and wherein the Verstellwellenendrehwinkel measured values and / or the angular velocity values are corrected by means of the correction value. This embodiment is based on the finding that, in the case of a multiple passing movement of a magnetic segment of the rotor on a stationary magnetic sensor, the position measurement signal detected with the aid of the magnetic sensor always corresponds to the same magnet each time the magnetic sensor passes , Having error caused by the tolerance of the magnet segment. This error is determined by measurement or otherwise, to then determine a correction value with which the Verstellwellenendrehwinkel measured values are corrected at a later time when the relevant magnetic segment passes the magnetic field sensor again. Thus, a measurement inaccuracy caused by a tolerance of a magnet segment can be easily corrected in the speed signal. It is even possible to carry out this correction online at the currently measured speed value without a time delay occurring between the corrected speed value and the uncorrected speed value.

It is advantageous if the position of the magnetic segments is detected with the aid of a measuring device which has a plurality of magnetic field sensors on the stator, which are offset from one another in the circumferential direction of the stator in such a way that a number of magnetic segment sensor pulses are produced per revolution of the rotor relative to the stator. Combinations are traversed, and if for each of these magnetic segment sensor combinations each determines a correction value, stored and used to correct the Verstellwellendrehwinkel measured values and / or the angular velocity values. The phase angle of the camshaft relative to the crankshaft can then be adjusted with even greater precision. The number of magnetic segment-sensor combinations preferably corresponds to the product of the number of magnetic field sensors and the number of magnetic poles of the rotor.

In a preferred embodiment of the invention, the rotor is rotated relative to the stator in such a way that a number of magnetic segment sensor combinations are traversed, with the aid of the measuring device detecting first uncorrected adjustment shaft rotation angle measurement values and / or angular velocity values for these magnetic segment sensor combinations In addition, reference values for the Verstellwellenendrehwinkel and / or the angular velocity are detected, which has a greater accuracy than that of the first Verstellwellenendrehwinkel measured values or angular velocity values, wherein using the first uncorrected Verstellwellenendrehwinkel measured values or angular velocity values, the correction values are determined as correction factors wherein the magnetic segment-sensor combinations assigned to the first uncorrected adjustment shaft rotation angle measurement values or angular velocity values again pass through and in this case with the aid of the measurement device second e uncorrected Verstellwellenendrehwinkel measured values or angular velocity values are detected, and wherein these values are corrected using the previously determined correction factors. The correction values are thus determined in the form of correction factors, which makes it possible to correct the measurement errors caused by the tolerances of the magnet segment at different rotational speeds. The reference signal may be a measurement signal that is detected, for example, in the manufacture of the EC motor by means of an additional position measuring device. The reference signal may also be a speed and / or an integrated acceleration signal of a shaft coupled to the EC motor.

In an expedient embodiment of the invention, the reference values are formed by smoothing the first uncorrected adjustment shaft rotation angle measurement values or angular velocity values by filtering. As a result, an additional sensor for measuring the reference signal can be saved.

It is advantageous if the rotor is rotated relative to the stator such that the individual magnet segment sensor combinations occur at least twice, if a correction factor for the adjustment shaft rotation angle measurement values or angular velocity values is determined for the individual magnet segment sensor combinations if an average value is formed in each case from the correction factors determined for the individual magnet segment-sensor combinations, and if the mean values thus obtained are stored as new correction factors and the adjustment shaft rotation angle measurement values or angular velocity values when the magnet segment sensor combinations are re-run using the these correction factors are corrected. The individual magnetic segment sensor combinations are preferred to run through as often as possible, which is easily possible with an EC motor for an electronic camshaft adjustment, since this constantly rotates during operation of the internal combustion engine.

In one embodiment of the invention, the mean value is formed in each case as the arithmetic mean value. All the correction factors used for averaging enter into the mean value with the same weight.

In a preferred embodiment of the invention, a mean moving average is formed in each case, preferably in such a way that the weight with which the correction factors enter the mean value decreases with increasing age of the correction factors. New correction factors are therefore taken more into account in the mean value than correction factors which are assigned to a date that lies further back. Should an error occur which leads to a situation where a magnetic segment / sensor combination is not recognized and thus the correction factors already determined are assigned to the wrong magnet segments, the incorrect correction factor assignment only has a short-term effect on the correction of the rotational speed signal, i. the wrong correction factors are "forgotten" relatively quickly.

It is advantageous if the moving average values F _Neu [i (tT)] for the individual magnet segment sensor combinations are cyclically calculated according to the formula F _New [i (tT)] = λ F _Alt [i (tT)] + (1-λ F [i (tT)], where i is an index identifying the respective magnetic segment-sensor combination, t is the time, T is a delay time between the actual angular velocity and the measured angular velocity values, F _Alt [i (tT)] Mean value determined for the last mean value at the index i and λ mean a forgetting factor which is greater than zero and less than 1 and preferably in the interval between 0.7 and 0.9. Such averaging is well suited for online calculation. The Time T depends on the speed and decreases with increasing speed (event-controlled system).

1. a) der Läufer relativ zu dem Stator verdreht und die Korrekturfaktoren für die einzelnen Magnetsegment-Sensor-Kombinationen ermittelt und gespeichert werden,
2. b) dass danach die entsprechenden Magnetsegment-Sensor-Kombinationen erneut durchlaufen werden, wobei ein Satz neuer Korrekturfaktoren ermittelt wird,
3. c) dass die Korrekturfaktoren des alten Korrekturfaktorsatzes relativ zu denen des neuen Korrekturfaktorsatzes zyklisch vertauscht und die Korrekturfaktorsätze danach miteinander verglichen werden,
4. d) dass Schritt c) wiederholt wird, bis alle Vertauschungskombinationen des alten Korrekturfaktorsatzes mit dem neuen Korrekturfaktorsatz verglichen wurden,
5. e) dass die Vertauschungskombination, bei der eine maximale Übereinstimmung mit dem neuen Korrekturfaktorsatz auftritt, ermittelt wird,
6. f) und dass mit der dieser Vertauschungskombination zugeordneten Anordnung der Korrekturwerte des alten Korrekturfaktorsatzes die Winkelgeschwindigkeitswerte korrigiert werden.

In an advantageous embodiment of the invention, it is provided that

1. a) the rotor is rotated relative to the stator and the correction factors for the individual magnetic segment sensor combinations are determined and stored,
2. b) thereafter the respective magnetic segment-sensor combinations are run through again, whereby a set of new correction factors is determined,
3. c) that the correction factors of the old correction factor set are cyclically reversed relative to those of the new correction factor set and the correction factor sets are then compared with each other,
4. d) that step c) is repeated until all commutation combinations of the old correction factor set have been compared with the new correction factor set,
5. e) that the commutation combination at which a maximum match with the new correction factor set occurs is determined,
6. f) and that with the arrangement of the correction values of the old correction factor set assigned to this permutation combination, the angular velocity values are corrected.

In this way, the assignment of the correction factors to the magnet segments can be restored if, for example, it should have been changed unintentionally due to a disturbance of the measurement signal. Thus, the already determined correction factors can be used even after the occurrence of the fault. In this case, an identifier on the rotor of the EC motor, which allows an absolute measurement of the position of the rotor relative to the stator can be saved. In an advantageous manner, however, the method can also be used after the EC motor has been switched back on to associate correction factors, which were determined during an earlier switch-on phase of the EC motor and stored in a non-volatile memory, with those magnet segment-sensor combinations for which they were determined during the earlier switch-on phase.

Optionally, the correction factors can also be determined under ideal conditions in the manufacture of the EC motor, preferably in an end stage of production.

It is advantageous if, in the case of the permutation combination in which a maximum match between the correction factor sets occurs, respectively assigned correction factors of the old correction factor set and the new correction factor set are each averaged and stored as a new correction factor, and if obtained with the averaging obtained by this averaging Correction factor set the angular velocity values are corrected. Thus, both the correction factors of the first data set and those of the second data set are taken into account in the correction of the angular velocity values.

1. a) dass der Läufer derart relativ zu dem Stator verdreht wird, dass alle Magnetsegment-Sensor-Kombinationen mindestens einmal durchlaufen werden,
2. b) dass dabei ein Lagemesssignal der Magnetfeldsensoren derart generiert wird, dass pro Umdrehung des EC-Motors für jedes Polpaar des Läufers jeweils eine Anzahl von Messsignal-Zuständen durchlaufen wird,
3. c) dass ein erster Datensatz mit einer der Anzahl der Magnetsegment-Sensor-Kombinationen entsprechenden Anzahl Wertekombinationen, jeweils bestehend zumindest aus einem Korrekturfaktor für die betreffende Magnetsegment-Sensor-Kombination und einem dieser zugeordneten Messsignal-Zustand, ermittelt und gespeichert wird,
4. d) dass danach die entsprechenden Magnetsegment-Sensor-Kombinationen erneut durchlaufen werden, wobei ein neuer, zweiter Datensatz mit Wertekombinationen ermittelt und gespeichert wird,
5. e) dass bei einer Abweichung zwischen den Messsignal-Zuständen des ersten und denen des zweiten Datensatzes die Wertekombinationen des ersten Datensatzes derart zyklisch relativ zu denen des zweiten Datensatzes verschoben werden, dass die Messsignal-Zustände der Datensätze übereinstimmen,
6. f) dass danach die jeweils einander zugeordneten Korrekturfaktoren der Datensätze miteinander verglichen werden,
7. g) dass die Korrekturfaktoren des einen Datensatzes um eine der doppelten Anzahl der Magnetfeldsensoren entsprechende Anzahl Schritte relativ zu den Korrekturfaktoren des anderen Datensatzes zyklisch vertauscht und danach die jeweils einander zugeordneten Korrekturfaktoren der Datensätze miteinander verglichen werden,
8. h) dass Schritt g) gegebenenfalls wiederholt wird, bis alle Vertauschungskombinationen bearbeitet wurden,
9. i) dass eine Vertauschungskombination, bei der eine maximale Übereinstimmung zwischen den Korrekturfaktoren der Datensätze auftritt, ermittelt wird,
10. j) und dass mit der dieser Vertauschungskombination zugeordneten Anordnung der Korrekturwerte des ersten Datensatzes die Winkelgeschwindigkeitswerte korrigiert werden.

In a preferred embodiment of the invention it is provided that

1. a) that the rotor is rotated relative to the stator such that all magnetic segment sensor combinations are traversed at least once,
2. b) that in this case a position measurement signal of the magnetic field sensors is generated in such a way that in each case a number of measurement signal states are passed through per revolution of the EC motor for each pole pair of the rotor
3. c) that a first data set having a number of value combinations corresponding to the number of magnetic segment sensor combinations, each consisting of at least one correction factor for the relevant magnetic segment sensor combination and a measurement signal state assigned to it, is determined and stored,
4. d) that thereafter the corresponding magnetic segment sensor combinations are run through again, whereby a new, second data set with value combinations is determined and stored,
5. e) that in case of a deviation between the measurement signal states of the first and those of the second data set, the value combinations of the first data record are cyclically shifted relative to those of the second data record such that the measurement signal states of the data records match,
6. f) that thereafter the respective mutually associated correction factors of the data sets are compared with each other,
7. g) that the correction factors of one data set are cyclically interchanged by a number of steps corresponding to twice the number of magnetic field sensors relative to the correction factors of the other data set, and then the respective mutually associated correction factors of the data sets are compared with each other,
8. h) if necessary, step g) is repeated until all commutation combinations have been processed,
9. i) that a permutation combination in which a maximum match between the correction factors of the data sets occurs is determined,
10. j) and that the angular velocity values are corrected with the arrangement of the correction values of the first data set assigned to this permutation combination.

As a result of these measures, the assignment of the correction factors to the magnet segment-sensor combinations can be restored with relatively few permutation or shifting operations and thus correspondingly short time expenditure.

In this case, it is even possible for an average to be formed from the mutually associated correction factors of the first and second data sets in the case of the permutation combination in which a maximum match between the correction factors of the data sets is formed and stored as a new correction factor and that with the latter Averaging obtained correction factor set angular velocity values are corrected. Thus, both the correction factors of the first data set and those of the second data set are taken into account in the correction of the speed signal.

In an expedient embodiment of the method, the fluctuation ranges of the uncorrected angular velocity values and the corrected angular velocity values are each determined in a time window and compared with one another, wherein in the event that the fluctuation range of the corrected angular velocity values is greater than that of the uncorrected angular velocity values, the correction factors are newly determined and / or the assignment of the correction factors to the magnetic segment sensor combinations is restored. It is assumed that, in the event that the fluctuation of the corrected angular velocity values is greater than that of the uncorrected angular velocity values, an error has occurred in the assignment of the correction factors to the individual magnet segment-sensor combinations, for example by EMC irradiation. To correct this error, the correction factors can be reset to the value 1 and then re-adapted or the original assignment is restored, for example by cyclically interchanging the correction factors.

Conveniently, the correction factors are limited to a predetermined value range, which is preferably between 0.8 and 1.2. As a result, outliers in the corrected speed signal, which are caused by implausible, outside the predetermined value range lying correction factors can be suppressed.

In an advantageous embodiment of the invention, a moment of inertia for the mass moment of inertia of the rotor is determined, wherein a current signal I is detected by a respective current value l (k) is determined for the individual Verstellwellen measuring times for the electric current in the winding, wherein for the individual angular velocity values ω (k) are respectively determined from an angular velocity value ω _k (k-1) associated with a previous displacement wave measurement time, the current signal I and the moment of inertia value an estimated value ω _s (k) for the angular velocity value ω (k), this estimated value ω _s (k) is assigned a tolerance band in which the estimated value ω _s (k) is included, and wherein in the case that the angular velocity value w (k) is outside the tolerance band, the angular velocity value w (k) by one within the Tolerance band located angular velocity value ω _k (k) is replaced. Thus, angular velocity values w (k) which lie outside the tolerance band and which are therefore not plausible are limited to the tolerance band, the limit values for the tolerance band being determined dynamically. As a result, fluctuations in the angular velocity values can be easily smoothed without there being any appreciable time delay between the smoothed angular velocity signal and the measured angular velocity signal. The limitation is based on the dynamic equation of the electrical machine: $$\mathrm{J}\cdot \mathrm{d\; \omega }/\mathrm{d}\mathrm{t}={\mathrm{K}}_{\mathrm{t}}\cdot \mathrm{l}$$

J is the mass moment of inertia of the rotor, w the rotor speed, K _t a constant of the electric machine, I the winding current and t the time. The speed estimate ω _s (k) can be determined as follows, where T is a sampling period: $${\omega }_s\left(k\right)={\omega }_k\left(k-\mathit{1}\right)+\begin{array}{c}T\cdot K_t\cdot \mathrm{I}\left(\mathrm{k}\mathrm{-}\mathrm{1}\right)\\ \mathrm{J}\end{array}$$

$${\mathrm{\omega }}_{\mathit{LowLim}}\left(\mathrm{k}\right)={\mathrm{\omega }}_{\mathrm{s}}-\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{Grenz}}=\mathrm{\omega }\left(\mathrm{k}-1\right)+T{K}_t\cdot I\left(k-1\right)/J-\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{Grenz}}$$

When the width of the tolerance band is set to ± Δω _limit , the upper _limit value ω _HighLim (k) and the lower _limit value ω _LowLim (k) of the tolerance _band for the k-th speed _measurement value w (k) can be derived from the estimated value ω _s as follows be determined: $${\mathrm{\omega }}_{\mathit{HighLim}}\left(\mathrm{k}\right)={\mathrm{\omega }}_{\mathrm{s}}+\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{border}}=\mathrm{\omega }\left(\mathrm{k}-1\right)+T{K}_t\cdot I\left(k-1\right)/\mathrm{J}+\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{border}}$$

$${\mathrm{\omega }}_{\mathit{LowLim}}\left(\mathrm{k}\right)={\mathrm{\omega }}_{\mathrm{s}}-\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{border}}=\mathrm{\omega }\left(\mathrm{k}-1\right)+T{K}_t\cdot I\left(k-1\right)/J-\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{border}}$$

In this case, the width ± Δω _{limit of} the tolerance band is preferably selected to be significantly smaller than the fluctuation range of the rotational speed measured values w (k) in order to achieve a noticeable reduction in the fluctuation of the angular velocity values.

In an advantageous embodiment of the invention, the rotor is loaded with a load torque, wherein a load torque signal M _{L is} provided for the load torque, and wherein the estimated value ω _s (k) is in each case from the angular velocity value ω _k (k-1) assigned to the earlier sampling instant. , the current signal I, the load torque signal M _L and the moment of inertia value is determined. The dynamic equation of the EC motor is then: $$\mathrm{J}\cdot \mathrm{d}\mathrm{\omega }/\mathrm{d}\mathrm{t}={\mathrm{K}}_{\mathrm{t}}\cdot \mathrm{l}-{\mathrm{M}}_{\mathrm{L}}$$

$${\mathrm{\omega }}_{\mathit{HighLim}}\left(\mathrm{k}\right)={\mathrm{\omega }}_{\mathrm{S}}+\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{Grenz}}=\mathrm{\omega }\left(\mathrm{k}-1\right)+T/\mathrm{J}\left[K_t\cdot \mathit{l}\left(k-1\right)-{\mathrm{M}}_{\mathrm{L}}\left(\mathrm{k}-1\right)\right]+\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{Grenz}}$$

$${\mathrm{\omega }}_{\mathit{LowLim}}\left(\mathrm{k}\right)={\mathrm{\omega }}_{\mathrm{S}}-\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{Grenz}}=\mathrm{\omega }\left(\mathrm{k}-1\right)+T/\mathrm{J}\left[K_t\cdot I\left(k-1\right)-{\mathrm{M}}_{\mathrm{L}}\left(\mathrm{k}-1\right)\right]-\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{Grenz}}$$

From this, the angular velocity estimate ω _s (k) and the upper boundary value ω _HighLim (k) and the lower boundary value ω _LowLim (k) of the tolerance _band can be determined as follows: $${\omega }_S\left(k\right)={\omega }_k\left(k-\mathit{1}\right)+\begin{array}{c}T\cdot K_t\cdot \mathrm{l}\left(\mathrm{k}-1\right)\\ \mathrm{J}\end{array}-\begin{array}{c}T\cdot {\mathrm{M}}_L\left(\mathrm{k}-1\right)\\ \mathrm{J}\end{array}$$

$${\mathrm{\omega }}_{\mathit{HighLim}}\left(\mathrm{k}\right)={\mathrm{\omega }}_{\mathrm{S}}+\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{border}}=\mathrm{\omega }\left(\mathrm{k}-1\right)+T/\mathrm{J}\left[K_t\cdot \mathit{l}\left(k-1\right)-{\mathrm{M}}_{\mathrm{L}}\left(\mathrm{k}-1\right)\right]+\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{border}}$$

$${\mathrm{\omega }}_{\mathit{LowLim}}\left(\mathrm{k}\right)={\mathrm{\omega }}_{\mathrm{S}}-\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{border}}=\mathrm{\omega }\left(\mathrm{k}-1\right)+T/\mathrm{J}\left[K_t\cdot I\left(k-1\right)-{\mathrm{M}}_{\mathrm{L}}\left(\mathrm{k}-1\right)\right]-\mathrm{\Delta }{\mathrm{\omega }}_{\mathit{border}}$$

In an expedient embodiment of the invention, the voltage applied to the winding electrical voltage is detected, wherein the current values l (k) indirectly from the voltage, the impedance of the winding, the optionally corrected speed measurement w (k) and an engine constant K _{e is} determined. The corresponding system equation is: $$\mathrm{U}={\mathrm{R}}_{\mathrm{A}}\cdot \mathrm{l}+{\mathrm{L}}_{\mathrm{A}}\cdot \mathrm{d}\mathrm{l}/\mathrm{d}\mathrm{t}+{\mathrm{K}}_{\mathrm{e}}\cdot {\mathrm{\omega }}_{\mathrm{k}}$$

Here, R _{A is} the ohmic resistance of the winding, L _{A is} the inductance of the winding and K _{e is} the motor constant of the EC motor. The method is preferably used in EC motors, in which the winding current is adjusted by pulse width modulation of an electrical voltage applied to the winding.

It is advantageous if the width and / or position of the tolerance band is selected as a function of the angular velocity value ω _k (k-1) assigned to the previous adjustment shaft measuring time and is preferably reduced with increasing angular velocity and / or increased with decreasing angular velocity. If there is an average value for the load torque of the camshaft, the accuracy of which depends on the rotational speed, the speed dependency of the accuracy in determining the width of the tolerance band can be taken into account.

In an expedient embodiment of the invention, the width and / or position of the tolerance band is selected as a function of the current signal I and preferably increased with increasing current and / or reduced with decreasing current. It is assumed that in a large winding current of the rotor is usually accelerated so that the speed increases accordingly. The width and / or position of the tolerance band is thus adapted to the expected due to the energization of the winding speed changes of the rotor.

If the speed signal is subject to interference, such as ripple, usually the winding current fluctuates accordingly. In this case, it may be advantageous for the current signal I to be smoothed by filtering, in particular by moving averaging, and when the estimated values ω _s (k) for the angular velocity values w (k) are determined with the aid of the filtered current signal l.

In an advantageous embodiment of the invention, in each case at least two crankshaft rotation angle measurement values, the time difference between the crankshaft rotation angle measurement times assigned to these measurement values and the time interval between the last crankshaft measurement time and the reference time, an estimated value for the angle of rotation which the crankshaft has at the reference time , extrapolated, wherein the time difference between the reference time and the last crankshaft measuring time is determined, and wherein the estimated value of the crankshaft rotation angle measured value at the last crankshaft measuring time, the time difference and the angular speed value is determined. By this measure, in combination with the extrapolation of Verstellwellen measuring times a particularly high precision in the adjustment of the phase angle can be achieved.

Fig. 1:

eine schematische Darstellung eine Kurbelwellen-Nockenwellenanordnung eines Hubkolben-Verbrennungsmotors, die eine Verstellvorrichtung zum Verändern der Drehwinkellage der Nockenwelle relativ zur Kurbelwelle aufweist,

Fig. 2

eine graphische Darstellung des tatsächlichen Drehwinkelverlaufs und von Drehwinkel-Messwerten des Rotors eines Verstellmotors der Verstellvorrichtung, wobei auf der Abszisse die Zeit und auf der Ordinate der Drehwinkel aufgetragen ist,

Fig. 3

eine graphische Darstellung des tatsächlichen Drehwinkelverlaufs des Verstellmotors, wobei die Stellen, an denen Hallsensor-Pulse auftreten, im Drehwinkelverlauf markiert sind, wobei auf der Abszisse die Zeit und auf der Ordinate der Drehwinkel aufgetragen ist,

Fig. 4

eine schematische Ansicht auf die Stirnseite des Läufers eines EC-Motors, wobei am Umfang des Läufers Magnetsegmente angeordnet sind, und wobei eine Lagemesseinrichtung zur Detektion der Lage des Läufers relativ zum Stator vorgesehen ist,

Fig. 5

eine graphische Darstellung eines mit Hilfe der Lagemesseinrichtung erfassten Lagemesssignals,

Fig. 6

ein Ablaufdiagramm, welches die einzelnen Schritte bei der Korrektur eines aus dem Lagemesssignal erzeugten Winkelgeschwindigkeitssignals verdeutlicht, und

Fig. 7

eine graphische Darstellung von Korrekturfaktoren, wobei die Beträge der Korrekturfaktoren als Balkendiagramm dargestellt sind, wobei unterhalb des Balkens jeweils ein Wert eines dem betreffenden Korrekturfaktor zugeordneten Lagemesssignals und darunter jeweils ein Index abgebildet sind, der den betreffenden Korrekturfaktor einer Magnetsegment-Sensor-Kombination zuordnet.

Below are exemplary embodiments of the invention are explained in more detail with reference to the drawing. Show it:

Fig. 1:

1 is a schematic representation of a crankshaft camshaft arrangement of a reciprocating internal combustion engine having an adjusting device for changing the rotational angle position of the camshaft relative to the crankshaft,

Fig. 2

a graphical representation of the actual rotation angle curve and rotational angle measured values of the rotor of an adjusting motor of the adjusting device, wherein the abscissa is the time and plotted on the ordinate of the rotation angle,

Fig. 3

a graphical representation of the actual rotation angle curve of the variable displacement motor, wherein the locations at which Hall sensor pulses occur, are marked in the rotation angle curve, wherein the abscissa is the time and plotted on the ordinate of the rotation angle,

Fig. 4

a schematic view of the front side of the rotor of an EC motor, wherein magnet segments are arranged on the circumference of the rotor, and wherein a position measuring device is provided for detecting the position of the rotor relative to the stator,

Fig. 5

a graphical representation of a detected by means of the position measuring position measurement signal,

Fig. 6

a flowchart illustrating the individual steps in the correction of an angular velocity signal generated from the position measurement signal, and

Fig. 7

a graphical representation of correction factors, the amounts of the correction factors are shown as a bar graph, below the bar each having a value of the respective correction factor associated position measurement signal and below each an index are mapped, which assigns the relevant correction factor of a magnetic segment sensor combination.

An adjusting device for adjusting the angle of rotation or phase of the camshaft 11 of a reciprocating internal combustion engine relative to the crankshaft 12 has an adjusting 13, which is designed as a three-shaft gear with a crankshaft fixed drive shaft, a camshaft fixed output shaft and a standing with the rotor of an adjusting motor in drive connection adjusting shaft , To determine measured values for the phase angle, a measured value for the crankshaft rotation angle is detected at each crankshaft measuring time. In addition, a measured value for the Verstellwellenendrehwinkel is measured at Verstellwellen-measuring times. From the measured value for the crankshaft rotation angle and the adjustment shaft rotation angle, a value for the phase position is determined with the aid of a known stationary gear ratio of the three-shaft transmission.

In Fig. 1 It can be seen that an inductive sensor 15 is provided for measuring the crankshaft rotation angle, which detects the tooth flanks of a gear rim 16 consisting of a magnetically conductive material arranged on the crankshaft 12. One of the tooth gaps or teeth of the toothed rim 16 has a greater width than the other tooth gaps or teeth and serves as a reference mark. When passing the reference mark on the sensor 15, the measured value for the crankshaft rotation angle is set to a starting value. Thereafter, the measured value is tracked until the reference mark is passed by the sensor 15 each time a tooth flank is detected. The tracking of the measured value for the crankshaft angle takes place with the aid of a control device in whose operating program an interrupt is triggered in each case when a tooth flank is detected. The crankshaft rotation angle is therefore measured digitally.

As an adjusting motor, an EC motor 14 is provided, which has a rotor, on the circumference of a series of magnet sections alternately magnetized in opposite directions is arranged, which has an air gap with teeth of a stator interact magnetically. The teeth are wound with a winding, which is energized via a drive device.

The position of the magnet segments relative to the stator and thus the Verstellwellenendrehwinkel is detected by means of a measuring device 17 having a plurality of magnetic field sensors A, B, C, which are arranged offset to one another in the circumferential direction of the stator to each other, that per revolution of the rotor a number is traversed by magnetic segment sensor combinations. As reference value generator for the camshaft rotation angle, a Hall sensor 18 is provided, which cooperates with a arranged on the camshaft 11 trigger 19. If the Hall sensor 18 detects an edge of the trigger wheel 19, an interrupt is triggered in the operating program of the control unit, in which the crankshaft rotation angle and the Verstellwellenendrehwinkel be cached. This interrupt will also be referred to as a camshaft interrupt below.

The camshaft-triggered absolute angle ε _Abs and the relative displacement angle Δε _Rel are _currently calculated at the actual displacement angle ε. A signal _currently representing the current displacement angle ε is present at an actual value input of a control circuit provided for controlling the phase position. The absolute _angle ε _Abs is the crankshaft _angle at a time t _TrigNw at which the camshaft interrupt is triggered: $${\mathrm{\epsilon }}_{\mathit{Section}}={\mathrm{\epsilon }}_{\mathit{KW}}\left(t_{\mathit{TrigNW}}\right)$$

$${\epsilon }_{\mathit{Aktuell}}={\mathrm{\varphi }}_{\mathit{KW},\mathit{TrigNW}}+\frac{1}{i_g}\cdot \left(\left[{\mathrm{\varphi }}_{\mathit{KW}}-{\mathrm{\varphi }}_{\mathit{KW},\mathit{TrigNW}}\right]-2\cdot \left[{\mathrm{\varphi }}_{\mathit{Em}}-{\mathrm{\varphi }}_{\mathit{Em}\mathit{,}\mathit{TrigNW}}\right]\right)$$

The angular position Δε _{Rel of} the camshaft 11 relative to the crankshaft 12 is calculated from the time-synchronous changes (controller sampling) of the angle counter of rotor Δφ _Em and crankshaft Δφ _KW relative to the reference values for camshaft triggering via the transmission fundamental equation of the three-shaft transmission: $${\epsilon }_{\mathit{Current}}={\epsilon }_{\mathit{Section}}+{\epsilon }_{\mathrm{re}l}={\epsilon }_{\mathit{Section}}+\frac{1}{i_G}\cdot \left(\Delta {\phi }_{KW}-2\cdot \Delta {\mathrm{\phi }}_{em}\right)$$

$${\epsilon }_{\mathit{Current}}={\mathrm{\phi }}_{\mathit{KW}.\mathit{TrigNW}}+\frac{1}{i_G}\cdot \left(\left[{\mathrm{\phi }}_{\mathit{KW}}-{\mathrm{\phi }}_{\mathit{KW}.\mathit{TrigNW}}\right]-2\cdot \left[{\mathrm{\phi }}_{\mathit{em}}-{\mathrm{\phi }}_{\mathit{em}\mathit{.}\mathit{TrigNW}}\right]\right)$$

In this case, i _{g is} the stationary gear ratio between the camshaft 11 and the adjusting shaft: $$i_G={\frac{n_{\mathit{em}}}{n_{\mathit{northwest}}}|}_{n_{\mathit{kw}}=0}$$

In order to be able to calculate the rotational angle position Δε _Rel , the angles of the crankshaft φ _{KW, TrigNW} and the EC motor rotor or the adjusting _shaft φ _{Em, TrigNW are stored} at the time of the camshaft _trigger . At a later point in time, an interrupt is then initiated in the operating program of the control device, in which the rotational angle position Δε _{Rel is} calculated with the aid of the intermediately _stored angles φ _{KW, TrigNW} and (φ _{Em, TrigNW} .

wobei die Unsicherheitsband (bei positiver Drehzahl) einseitig von -0 bis +8,57° angesetzt werden darf, da der Winkel jeweils zum Zeitpunkt eines Wechsels der Magnetsegment-Sensor-Kombinationen als exakt angenommen wird und danach zunimmt. Würde man die relative Drehwinkellage Δε_Rel direkt aus dem Kurbelwellendrehwinkel ϕ_KW,TrigNW und dem Verstellwellendrehwinkel ϕ_Em,TrigNW berechnen, ergäbe sich eine Messunsicherheit für die relative Drehwinkellage Δε_Rel von -0,29° bis +0.49°: $${\epsilon }_{-0.29}^{+0.49}={{\mathrm{\varphi }}_{\mathit{KW}\mathit{,}\mathit{TrigNW}}}_{-0}^{+0.2}+\frac{1}{i_g}\left(\left[{{\mathrm{\varphi }}_{\mathit{KW}}}_{-0}^{+0.2}-{{\mathrm{\varphi }}_{\mathit{KW},\mathit{TrigNW}}}_{-0}^{+0.2}\right]-2\cdot \left[{{\mathrm{\varphi }}_{\mathit{Em}}}_{-0}^{+8.57}-{{\mathrm{\varphi }}_{\mathit{Em},\mathit{TrigNW}}}_{-0}^{+8.57}\right]\right).$$

The resolution of the relative angular position Δε _Rel results from an uncertainty analysis of the individual components of Eq. (1.1). The crankshaft rotation angle has, for example, an uncertainty of -0 to + 0.2 °. The resolution δ _{EM of} the measuring device 17 results from the number of pole pairs P (eg P = 7) and the number m (eg m = 3) of the magnetic field sensors A, B, C: $${\delta }_{\mathit{em}}=\frac{360°}{2\cdot m\cdot P}=\frac{360°}{2\cdot 3\cdot 7}=8.57°.$$

wherein the uncertainty band (at positive speed) may be set on one side from -0 to + 8.57 °, since the angle is assumed to be exact at the time of a change of the magnetic segment-sensor combinations and then increases. If one were to calculate the relative angular position Δε _Rel directly from the crankshaft rotation angle φ _{KW, TrigNW} and the adjustment _shaft rotation angle φ _{Em, TrigNW} , this would result in a measurement uncertainty for the relative rotational position Δε _Rel from -0.29 ° to + 0.49 °: $${\epsilon }_{-\mathrm{12:29}}^{+\mathrm{12:49}}={{\mathrm{\phi }}_{\mathit{KW}\mathit{.}\mathit{TrigNW}}}_{-0}^{+0.2}+\frac{1}{i_G}\left(\left[{{\mathrm{\phi }}_{\mathit{KW}}}_{-0}^{+0.2}-{{\mathrm{\phi }}_{\mathit{KW}.\mathit{TrigNW}}}_{-0}^{+0.2}\right]-2\cdot \left[{{\mathrm{\phi }}_{\mathit{em}}}_{-0}^{+\mathrm{8:57}}-{{\mathrm{\phi }}_{\mathit{em}.\mathit{TrigNW}}}_{-0}^{+\mathrm{8:57}}\right]\right),$$

As in Fig. 2 can be seen, the digitization of the Verstellwellenendrehwinkels causes a kind of beating between the times at which the cyclic interrupt occurs, and the times at which the magnetic segment sensor combinations change. Stationarily, the EC motor 14 rotates exactly twice as fast as the crankshaft 12. Typically, the times at which the cyclic interrupt occurs differ from the times at which the magnetic segment-sensor combinations alternate. In Fig. 2 For example, nine changes occur The magnetic segment-sensor combinations within eight interrupt cycles, ie per interrupt cycle, the electric motor covers an angle of (9/8) * 8.57 °. Since only an integer multiple of 8.57 ° is read in the control unit, the difference between true Verstellwellenendrehwinkel and the Verstellwellenendrehwinkel processed in the control unit is getting larger, until a Hall sensor pulse more than usual arrives at a cyclic interrupt, and true and measured Verstellwellenendrehwinkel short-term are in sync again.

If the relative angular position Δε _{Rel were} calculated directly from the crankshaft rotation angle φ _{KW, trigNW} and the adjustment shaft rotation angle φ _{Em, TrigNW} , then, according to Eq. (1) Jumps in the measured rotational position Δε _Rel , which have a size of Δε = 2 · δ _Em / i _g = 0.29 ° and would cause a controller intervention. This is undesirable especially in stationary operation.

In order to reduce the height of these jumps or even to avoid them altogether, an extrapolation of in each case at least two adjustment shaft rotation angle measurement values is an estimated value for the angle of rotation which the adjustment shaft has at reference point which lies after the adjustment shaft measurement times. On the one hand, the points in time at which the camshaft interrupts occur and, on the other hand, the points in time at which the cyclic interrupts are triggered are selected as reference times.

The extrapolation will be explained below Fig. 3 explained. At time t _Trig NW of the camshaft interrupt, the count corresponding to the Verstellwellenendrehwinkelwert N _TrigNW the measuring device 17, the time _{.DELTA.T TrigNw} and the speed ω _{Em, TrigNW} (signed) are the last change of the magnetic _segment sensor combination available. Corresponding data can be accessed at each cyclic interrupt t _i . For example, at time t ₁₈ the count N _t18 , the difference time Δt ₁₈ and the speed ω _{Em, t18 are} available.

$${\mathrm{\phi }}_{\mathrm{Em},\mathrm{ti}}={\mathrm{N}}_{\mathrm{ti}}\cdot {\mathrm{\delta }}_{\mathrm{Em}}+\mathrm{\Delta }{\mathrm{t}}_{\mathrm{i}}\cdot {\mathrm{\Delta }}_{\mathrm{Em},\mathrm{ti}}$$

With this data, the angle swept since the last change of the magnetic segment-sensor combination, and thus the EC motor or Verstellwellenendrewinkel the camshaft trigger and the current ECU interrupt t _j can be determined more accurately than before: $${\mathrm{\phi }}_{\mathrm{em}.\mathrm{TrigNW}}={\mathrm{N}}_{\mathrm{TrigNW}}\cdot {\mathrm{\delta }}_{\mathrm{em}}+\mathrm{\Delta }{\mathrm{t}}_{\mathrm{TrigNW}}\cdot {\mathrm{\omega }}_{\mathrm{em}.\mathrm{TrigNW}}$$

$${\mathrm{\phi }}_{\mathrm{em}.\mathrm{ti}}={\mathrm{N}}_{\mathrm{ti}}\cdot {\mathrm{\delta }}_{\mathrm{em}}+\mathrm{\Delta }{\mathrm{t}}_{\mathrm{i}}\cdot {\mathrm{\Delta }}_{\mathrm{em}.\mathrm{ti}}$$

The differential angle necessary for the calculation of the phase angle to the current ECU interrupt t _i is accordingly: $$\mathrm{\Delta }{\mathrm{\phi }}_{\mathrm{em}.\mathrm{ti}}={\mathrm{\phi }}_{\mathrm{em}.\mathrm{ti}}-{\mathrm{\phi }}_{\mathrm{em}.\mathrm{TrigNW}}=\left({\mathrm{N}}_{\mathrm{ti}}-{\mathrm{N}}_{\mathrm{TrigNW}}\right)\cdot {\mathrm{\delta }}_{\mathrm{em}}+\left[\mathrm{\Delta }{\mathrm{t}}_{\mathrm{i}}\cdot {\mathrm{\omega }}_{\mathrm{em}.\mathrm{ti}}-\mathrm{\Delta }{\mathrm{t}}_{\mathrm{TrigNW}}\cdot {\mathrm{\Delta }}_{\mathrm{em}.\mathrm{TrigNW}}\right]$$

Extrapolation requires the current EC engine speed. It can be most easily obtained from the time Δt _Hall between the last and penultimate Verstellwellen measuring time or the time period Δt _Hall between the last and penultimate change of the magnetic segment sensor combination (this information is available without time delay directly available). Together with the sign S of the counting direction results: $${\mathrm{\omega }}_{\mathrm{em}}=\mathrm{S}\cdot {\mathrm{\delta }}_{\mathrm{em}}/\mathrm{\Delta }{\mathrm{t}}_{\mathrm{Hall}}\mathrm{,}$$

This method is very simple, but can give very variable values, since the times Δt _Hall between the changes of the magnetic segment-sensor combination can be very irregular even at constant speed due to manufacturing tolerances. Basically, in order to improve the result, it is possible to average over several adjustment shaft angular values. It should be noted, however, that the mean value can only be calculated with a time delay so that when the EC motor 14 accelerates, this error is included in the extrapolation. In the ECU interrupt, the current speed ω _{Em of} the EC motor 14 is also calculated for the control of the phase angle.

The following is based on Fig. 4 to 7 explains how the influence of the errors occurring by the said manufacturing tolerances on the rotational position of the camshaft relative to the crankshaft can be reduced without a time delay.

At the in Fig. 4 embodiment shown, the rotor has eight magnet segments 1..8, which are offset in a grid of 45 ° in the circumferential direction of a support member 9 to which the magnet segments are fixed 1..8, to each other. The magnet segments 1..8 each form a magnetic pole on the circumference of the rotor, resulting in a total of a number of p pole pairs over the circumference. In Fig. 4 this is exemplified for a rotor with p = 4 pole pairs. On the ring formed by the magnet segments 1..8, the magnetization thus changes direction 8 times per revolution. As already mentioned, show the magnet segments 1..8 both in terms of their position and in terms of their dimensions in the circumferential direction tolerances. The mechanical angle α between mutually corresponding points of adjacent magnet segments 1. 8 can thus deviate from the nominal value 180 ° / p (in this case 45 °). The direction of rotation of the runner is in Fig. 4 indicated by the arrow Pf.

The output signal of the magnetic field sensor A changes in each case during a rotation of the rotor by the angle α. With the help of the magnetic field sensor A alone, a resolution of the rotor angle of rotation of α could thus be achieved. As in Fig. 4 can be seen, the sensors A, B, C are arranged offset from one another on the circumference of the rotor. The offset is chosen such that the position measurement signal detected with the aid of the sensors A, B, C has a resolution of 180 ° / (p · m). This is achieved in that the magnetic field sensor B by a mechanical angle of 180 ° / (m · p) plus an integral multiple of β = 180 ° / m with respect to the magnetic field sensor A and the magnetic field sensor C by twice this mechanical angle relative to the magnetic field sensor A is offset in forward direction Pf.

In Fig. 5 is a portion of the composed of the output signals A ', B', C 'of the sensors A, B, C Verstellwellenendrehwinkelsignals for a clockwise rotation in the direction of the arrow Pf shown. The output signal A 'is assigned to the magnetic field sensor A, the output signal B' to the magnetic field sensor B, etc. The output signals A ', B', C 'are digital signals which can assume the logic values 1 or 0. In this case, the value 1 occurs when the respective sensor A, B, C is opposite to a north pole forming magnetic segment 1..8. In a corresponding manner, the output signal A ', B', C 'assumes the logic value 0, when the relevant sensor A, B, C is opposite to a south pole forming magnetic segment 1..8.

In order to clarify the assignment of the individual values of an output signal to the respective magnetic field section 1. 8 moved past the relevant sensor A, B, C, the reference value of the respective magnetic field section 1. In Fig. 5 are below the output signals on the abscissa each of the magnetic rotation angle φ _magnetic and the mechanical rotation angle φ _mechanically applied. It can clearly be seen that with a mechanical rotation of 360 ° / p (= 90 °) the Verstellwellenendrehwinkelsignal successively 2 · m (= 6) assumes different states, which then repeat.

The Verstellwellenendrehwinkelsignal composed of the output signals A ', B' and C 'is transmitted for evaluation to the control unit, which is connected to the magnetic field sensors A, B, C. Only the output signals A ', B' and C 'are known to the control unit, but not which magnetic segments 1. 8 are being moved past the sensors A, B, C.

In Fig. 5 It can be seen that always one of the magnet segment sensor combinations is currently active. In Fig. 5 From left to right, these are the magnet segment sensor combinations (1,6,3), (1,6,4), (1,7,4), (2,7,4), (2,7,5 ), (2,8,5), etc. This sequence of magnetic segment-sensor combinations is repeated after 2 · p magnetic segments 1..8 have passed a magnetic field sensor A, B, C, ie after a mechanical full rotation.

By counting the changes at which the position measurement signal changes its value, the total rotation angle of the rotor is determined. Starting from a start value, the total angle is incremented with each change.

The Verstellwellenendrehwinkelsignal thus determined is differentiated to form a speed signal. This can be done, for example, such that the time .DELTA.t measured between two changes of the Verstellwellendrehwinkelsignals and the rotational speed ω is determined as follows: $$\mathrm{\omega }=\mathrm{\pi }/\left(\mathrm{m}\cdot \mathrm{p}\cdot \mathrm{\Delta }\mathrm{t}\right)\left[\mathrm{wheel}/\mathrm{s}\right]\mathrm{,}$$

Due to the tolerances of the magnet segments 1..8, the speed signal ω measured _{, i} determined in this way is subject to errors which, for example, lead to a jump in the speed signal at a constant actual rotational speed of the rotor.

In the controller, the magnetic segment sensor combinations of 1 to 2 * m * p are numbered consecutively, so that the count, hereinafter referred to as "index i", starts up and then jumps to 1 upon reaching 2 * m * p , When the EC motor is turned on, the index i is set to a starting value, e.g. to the value 1.

For each magnetic segment-sensor combination, a correction factor F _Adap [i] is now determined, which is assigned to the corresponding magnet segment 1..8 via the index i. This correction factor F _Adap [i] corresponds to the ratio between the rotational speed value ω _{Mess, i} , which is determined by means of the adjustment _shaft rotation angle _signal for the ith magnet segment-sensor combination was determined, and a reference rotational speed ω _Ref , which is assumed to have a greater accuracy than the rotational speed value ω _{Mess, i} . The correction _factors F _Adap [i] are stored in a data memory of the control unit.

With the aid of the correction factor F _Adap [i], a corrected rotational speed value ω _{Korr, i is} determined in each case for each rotational speed value ω _{Mess, i} as follows: $${\mathrm{\omega }}_{\mathrm{corr}.\mathrm{i}}={\mathrm{\omega }}_{\mathrm{measuring}.\mathrm{i}}/{\mathrm{F}}_{\mathrm{Adap}}\left[\mathrm{i}\right].$$

The correction _factors F _Adap [i] are determined in a learning process. At the start of the learning process, all correction _factors F _Adap [i] are set to the value 1, ie the corrected rotational speed ω _{Korr, i} initially corresponds to the measured rotational speed ω _{Mess, i} . During the learning process, the correction _factors F _Adap [i] are limited to a value range between 0.8 and 1.2 in order to limit the amount of error in the event of an incorrect adaptation, which in practice can not be completely ruled out.

A:

Die Differenzzeit Δt zwischen dem letzten und dem aktuellen Wechsel der Magnetsegment-Sensor-Kombination wird gespeichert. Sie zeigt an, wie lange das Überstreichen der zuvor aktiven Magnetsegment-Sensor-Kombination gedauert hat. Auf den dieser Magnetsegment-Sensor-Kombination zugeordneten Messwert des Lagemesssignals zeigt der Index i, der jeweils am Ende Sequenz für den Aufruf der nächsten Sequenz angepasst wird.

B:

Berechnung der unkorrigierten Drehzahl ω_Mess,i = π/(m·p·Δt).

C:

Filtern der unkorrigierten Drehzahl: Da die wahre Drehzahl ω_True unbekannt ist, wird das Referenzsignal für die Drehzahl durch Filterung der unkorrigierten Drehzahl gebildet. Das Ergebnis ω_Ref der Filterung stimmt relativ gut mit der tatsächlichen Geschwindigkeit vor T Sekunden überein, ω_Ref(t) ≈ ω_True(t-T). Dabei ist T die Verzögerungszeit des Filters, die von der Art und der Ordnung des Filters abweicht.

D:

Überprüfen der Adaptionsvoraussetzungen. Beispielsweise wird der Korrekturfaktor nicht adaptiert, wenn sich die Drehrichtung des Läufers geändert hat. Auch wird während einer Phase starker Beschleunigung und/oder Verzögerung des Läufers die Adaption des Korrekturfaktors ausgesetzt, da die gefilterte Drehzahl dann wahrscheinlich mit der tatsächlichen Drehzahl nicht genau übereinstimmt.

E:

Der tatsächliche Korrekturfaktor zu der letzten Magnetsegment-Sensor-Kombination ergibt sich als Quotient aus der berechneten Drehzahl ω_Mess,i(t) und dem wahren Drehzahlsignal ω_True(t), $${\mathrm{F}}_{\mathrm{True}}\left[\mathrm{i}\right]={\mathrm{\omega }}_{\mathrm{Mess},\mathrm{i}}\left(\mathrm{t}\right)/{\mathrm{\omega }}_{\mathrm{True}}\left(\mathrm{t}\right)$$

Da die wahre Drehzahl ω_True nur mit einer Verzögerung T in Form der Referenzdrehzahl ω_Ref zur Verfügung steht, müssen alle anderen beteiligten Größen ebenfalls verzögert werden. Deshalb sind der Index i und die unkorrigierten Drehzahlwerte ω_Mess,i in einem Schieberegister gespeichert, damit ihre Verzögerungswerte jetzt zur Verfügung stehen. Somit ergibt sich der Korrekturfaktor zu: $$\mathrm{F}\left[\mathrm{i}\left(\mathrm{t}-\mathrm{T}\right)\right]=\mathrm{\omega }{}_{\mathrm{Mess},\mathrm{i}}\left(\mathrm{t}-\mathrm{T}\right)/{\mathrm{\omega }}_{\mathrm{Ref}}\left(\mathrm{t}\right).$$

F:

Mittelwertbildung für den Korrekturfaktor: Der Korrekturfaktor F weist noch eine gewisse Ungenauigkeit auf, da der Drehzahl-Referenzwert ω_Ref mit dem tatsächlichen Drehzahlwert ω_True nur näherungsweise übereinstimmt. Bei den einzelnen Umdrehungen des Läufers werden deshalb jeweils neue Korrekturfaktoren ermittelt, wobei diese nach und nach für die jeweilige Magnetsegment―Sensor―Kombination ermittelten Korrekturfaktoren durch Bildung eines gleitenden Mittelwerts gemittelt werden: $${\mathrm{F}}_{\mathrm{Neu}}\left[\mathrm{i}\left(\mathrm{t}-\mathrm{T}\right)\right]=\mathrm{\lambda }{\mathrm{F}}_{\mathrm{Alt}}\left[\mathrm{i}\left(\mathrm{t}-\mathrm{T}\right)\right]+\left(1-\mathrm{\lambda }\right)\mathrm{F}\left[\mathrm{i}\left(\mathrm{t}-\mathrm{T}\right)\right]$$

Dabei bedeuten F_Neu der jeweils aktuelle Korrekturfaktor-Mittelwert, F_Alt der bei dem jeweils vorherigen Taktzyklus ermittelte Mittelwert und λ ein Vergessensfaktor, der zwischen 0 und 1 liegen kann. Je größer λ ist, desto länger werden vergangene Werte ω_Mess,i(t) berücksichtigt.

G:

Die Korrektur wird mit den aktuellen Werte i(t) und ω_Mess,1(t) durchgeführt. Mit dem bis dahin adaptierten Korrekturfaktor F[i] wird der Messwert korrigiert: $${\mathrm{\omega }}_{\mathrm{Korr},\mathrm{i}}={\mathrm{\omega }}_{\mathrm{Mess}}\left(\mathrm{t}\right)/\mathrm{F}\left[\mathrm{i}\right].$$

Die Korrektur des Drehzahlsignals wird mit Hilfe der zu der gerade zuvor überstrichenen Magnetsegment―Sensor―Kombination durchgeführt, während für die Adaption der Korrekturfaktoren F[i] ältere Werte verwendet werden.

H:

Speichern von i und ω_Mess,i in das Schieberegister, um später erneut auf diese Werte als Vergangenheitswerte zugreifen zu können.

J:

Zur Vorbereitung der nächsten Sequenz wird anhand der alten Magnetsegment-Sensor-Kombination der Index i erhöht. Überschreitet der Index i dabei das Intervall [1 .. 2·p·m], so wird er auf 1 gesetzt. Der Index i benennt jetzt die aktuelle Magnetsegment-Sensor-Kombination.

How out Fig. 6 is apparent, the following sequence is always run through when a change in the Verstellwellenendrehwinkelsignals is detected. The current time is called t.

A:

The difference time Δt between the last and the current change of the magnetic segment-sensor combination is stored. It indicates how long it took to sweep over the previously active magnet segment-sensor combination. The measured value of the position measurement signal assigned to this magnetic segment-sensor combination is shown by the index i, which in each case is adapted at the end to sequence for calling the next sequence.

B:

Calculation of the uncorrected speed ω _{Mess, i} = π / (m · p · Δt).

C:

Uncorrected speed filtering: Since the true speed ω _{True is} unknown, the speed reference signal is formed by filtering the uncorrected speed. The result ω _{Ref of} the filtering agrees relatively well with the actual speed before T seconds, ω _Ref (t) ≈ ω _True (tT). Where T is the delay time of the filter, which differs from the type and order of the filter.

D:

Check the adaptation requirements. For example, the correction factor will not be adapted if the direction of rotation of the rotor has changed. Also, during a phase of high acceleration and / or deceleration of the rotor, the adaptation of the correction factor is suspended, since the filtered speed will then probably not exactly match the actual speed.

e:

The actual correction factor for the last magnet segment-sensor combination is calculated as the quotient of the calculated speed ω _{Mess, i} (t) and the true speed signal ω _True (t), $${\mathrm{F}}_{\mathrm{true}}\left[\mathrm{i}\right]={\mathrm{\omega }}_{\mathrm{measuring}.\mathrm{i}}\left(\mathrm{t}\right)/{\mathrm{\omega }}_{\mathrm{true}}\left(\mathrm{t}\right)$$

Since the true speed ω _{True is} available only with a delay T in the form of the reference speed ω _Ref , all other variables involved must also be delayed. Therefore, the index i and the uncorrected speed values ω _{Mess, i} are stored in a shift register so that their delay values are now available. Thus, the correction factor is: $$\mathrm{F}\left[\mathrm{i}\left(\mathrm{t}-\mathrm{T}\right)\right]=\mathrm{\omega }{}_{\mathrm{measuring}.\mathrm{i}}\left(\mathrm{t}-\mathrm{T}\right)/{\mathrm{\omega }}_{\mathrm{Ref}}\left(\mathrm{t}\right),$$

F:

Averaging for the Correction Factor: The correction factor F still has a certain inaccuracy, since the speed reference value ω _Ref only approximately coincides with the actual speed value ω _True . Therefore, new correction factors are determined in each case during the individual rotations of the rotor, whereby these correction factors determined step by step for the respective magnet segment-sensor combination are averaged by forming a moving average: $${\mathrm{F}}_{\mathrm{New}}\left[\mathrm{i}\left(\mathrm{t}-\mathrm{T}\right)\right]=\mathrm{\lambda }{\mathrm{F}}_{\mathrm{Old}}\left[\mathrm{i}\left(\mathrm{t}-\mathrm{T}\right)\right]+\left(1-\mathrm{\lambda }\right)\mathrm{F}\left[\mathrm{i}\left(\mathrm{t}-\mathrm{T}\right)\right]$$

Where F _{New is} the current correction factor mean value, F _{Alt is} the mean value determined at the respective preceding clock cycle, and λ is a forgetting factor which can be between 0 and 1. The larger λ is, the longer are past values ω _{Mess, i} (t) considered.

G:

The correction is carried out with the current values i (t) and ω _{Mess, 1} (t). With the hitherto adapted correction factor F [i], the measured value is corrected: $${\mathrm{\omega }}_{\mathrm{corr}.\mathrm{i}}={\mathrm{\omega }}_{\mathrm{measuring}}\left(\mathrm{t}\right)/\mathrm{F}\left[\mathrm{i}\right],$$

The correction of the speed signal is performed by means of the magnetic segment-sensor combination just swept over, while older values are used for the adaptation of the correction factors F [i].

H:

Store i and ω _{Mess, i} in the shift register so that you can access these values as past values again later.

J:

In preparation for the next sequence, the index i is incremented using the old magnet segment-sensor combination. If the index i exceeds the interval [1 .. 2 · p · m], it is set to 1. Index i now names the current magnet segment-sensor combination.

A key point in the adaptation is the accuracy with which the actual speed is approximated. In the embodiment described above, this approximation is achieved by filtering the measured speed. But it is also possible to filter the already corrected speeds. If another measuring signal is available, from which the actual speed can be concluded, then this can also be used.

Upon de-energizing the EC motor and controller, the 2 * p * m learned correction factors are written to a nonvolatile data memory of the controller. Since, at the beginning of the adaptation, the index i is set to a randomly selected starting value for a magnet segment-sensor combination which was just accidentally active, and this magnet segment-sensor combination is initially unknown after the controller is switched on again, the assignment of the correction factors be checked to the magnetic segment sensor combinations and corrected in the determination of a faulty assignment, so that the correction factors can be used after restarting the controller.

The same problem already exists during the adaptation, if it is erroneously performed or not carried out, for example due to signal interference, so that the index i is updated incorrectly and thus the correction factors are assigned to magnetic segment-sensor combinations, which are opposite to the magnetic segment-sensor combinations for which the correction factors were determined are shifted. In such a case, the corrected speed ω _{Korr may} deviate significantly more from the actual speed than the uncorrected speed.

The data memory of the controller stores the correct order of the 2 m (= 6) successive position measurement signal states. This is compared with the order of the states of the position measurement signal. If a deviation is detected, this error is eliminated the next time the sequence is called. Namely, the change in the magnetic segment-sensor combinations is unique within ± m changes. If it is certain that the direction of rotation of the runner has been maintained during the disturbance, even (2 m-1) updates can be corrected.

The quality of the adaptation is monitored by repeatedly comparing the fluctuation range of the uncorrected and the corrected rotational speed over a specific time window. If the corrected speed fluctuates more than the uncorrected speed, an erroneous assignment is concluded. The assignment is then either restored or the correction factors are set to 1.

When restoring the assignment, it is assumed that the number sequence of the 2 · p · m correction factors represents a type of characteristic signature. If you adapt a new set of correction factors, they must have a very similar sequence of numbers, but the new sequence of numbers may be shifted from the previous sequence of numbers. To restore the assignment, the old sequence of numbers is therefore cyclically shifted 2 × p × m times and compared to the previous sequence of numbers after each shift step. In the case of the interchange combination in which the greatest correspondence between the old and the previous number sequence occurs, it is assumed that the numerical values of the old sequence of numbers are correctly assigned to the magnetic segment-sensor combinations. With this assignment, the correction of the speed signal and / or the further adaptation is then carried out.

• Zunächst wird ein erster Datensatz mit einer der Anzahl der Magnetsegment-Sensor-Kombinationen entsprechenden Anzahl Wertekombinationen, jeweils bestehend zumindest aus einem Korrekturfaktor für die betreffende Magnetsegment-Sensor-Kombination und einem dieser zugeordneten Messsignal-Zustand, ermittelt und gespeichert. Ein Ausführungsbeispiel eines solchen Datensatzes für einen EC-Motor 4 mit drei Magnetfeldsensoren und drei Polpaaren ist in der oberen Hälfte von Fig. 7 graphisch dargestellt.
• Danach werden die Magnetsegment-Sensor-Kombinationen, für welche die Korrekturfaktoren ermittelt wurden, erneut durchlaufen, wobei ein neuer, zweiter Datensatz mit Wertekombinationen ermittelt und gespeichert wird. Dieser zweite Datensatz ist in Fig. 7 unten graphisch dargestellt.
• Dann werden die Messsignal-Zustände des ersten und des zweiten Datensatzes miteinander verglichen. Wird dabei eine Abweichung festgestellt, werden die Wertekombinationen der Datensätze derart zyklisch relativ zueinander verschoben, dass die Messsignal-Zustände der Datensätze übereinstimmen. Bei dem Ausführungsbeispiel nach Fig. 7 kann dies dadurch erreicht werden, dass die Wertekombinationen der alten Adaption um drei Positionen zyklisch nach rechts verschoben werden.
• Danach werden die jeweils einander zugeordneten Korrekturfaktoren der Datensätze miteinander verglichen werden, also der Korrekturfaktor mit dem Index i=1 des ersten Datensatzes in Fig. 7 mit dem Korrekturfaktor mit dem Index i=4 des zweiten Datensatzes, der Korrekturfaktor mit dem Index i=2 des ersten Datensatzes mit dem Korrekturfaktor mit dem Index i=5 des zweiten Datensatzes, usw.
• In einem weiteren Schritt werden die Korrekturfaktoren des ersten Datensatzes um eine der doppelten Anzahl der Magnetfeld-Sensoren entsprechende Anzahl Schritte (also 2·p=6 Schritte) relativ zu den Korrekturfaktoren des anderen Datensatzes zyklisch vertauscht und danach die jeweils einander zugeordneten Korrekturfaktoren der Datensätze miteinander verglichen. Dieser Schritt wird wiederholt, bis alle Vertauschungskombinationen bearbeitet wurden.
• Danach wird die Vertauschungskombination, bei der eine maximale Übereinstimmung zwischen den Korrekturfaktorsätzen erreicht wird, ermittelt. Mit dieser Vertauschungskombination wird jeweils aus den einander zugeordneten Korrekturfaktoren der Korrekturfaktorsätze ein Mittelwert gebildet und als neuer Korrekturfaktor gespeichert wird. Mit den so ermittelten neuen Korrekturfaktoren wird dann das Drehzahlmesssignal korrigiert.

In another embodiment of the invention, the procedure is as follows:

• First, a first data set with a number of value combinations corresponding to the number of magnetic segment sensor combinations, each consisting of at least one correction factor for the relevant magnetic segment sensor combination and a measurement signal state associated therewith, is determined and stored. An embodiment of such a data set for an EC motor 4 with three magnetic field sensors and three pole pairs is in the upper half of Fig. 7 shown graphically.
• Thereafter, the magnetic segment-sensor combinations for which the correction factors were determined to run again, wherein a new, second set of value combinations is determined and stored. This second record is in Fig. 7 shown graphically below.
• Then, the measurement signal states of the first and the second data set are compared with each other. If a deviation is found, the value combinations of the data sets are cyclically shifted relative to one another such that the measurement signal states of the data records match. According to the embodiment Fig. 7 This can be achieved by shifting the value combinations of the old adaptation by three positions cyclically to the right.
• Thereafter, the mutually associated correction factors of the data sets are compared with each other, ie the correction factor with the index i = 1 of the first data set in FIG Fig. 7 with the correction factor with the index i = 4 of the second data set, the correction factor with the index i = 2 of the first data set with the correction factor with the index i = 5 of the second data set, etc.
• In a further step, the correction factors of the first data set are cyclically interchanged relative to the correction factors of the other data set by a number of steps corresponding to twice the number of magnetic field sensors (ie 2 * p = 6 steps) and then the mutually associated correction factors of the data sets with each other compared. This step is repeated until all commutation combinations have been edited.
• Thereafter, the commutation combination in which a maximum match between the correction factor sets is achieved is determined. With this permutation combination is in each case from the mutually associated correction factors the correction factor sets an average value is formed and stored as a new correction factor. The speed correction signal is then corrected with the new correction factors determined in this way.

So it does not have to be pushed twice. It just has to be found out which of the p magnetic periods fits best. During the time in which the new correction factors are adapted, the corrected speed is calculated either with the factor 1 or with the previously adapted correction factors.

LIST OF REFERENCE NUMBERS

1..8

magnetic segment

9

support part

11

camshaft

12

crankshaft

13

adjustment

14

EC motor

15

inductive sensor

16

sprocket

17

measuring device

18

Hall sensor

19

trigger wheel

α

Angle between two magnet segments

β

angle

A

magnetic field sensor

B

magnetic field sensor

C

magnetic field sensor

A '

Output signal of the magnetic field sensor A.

B '

Output signal of the magnetic field sensor B

C '

Output signal of the magnetic field sensor C

pf

direction of rotation

Claims (24)

1. Method for determining the rotational angle position of the camshaft (11) of a reciprocating piston internal combustion engine in relation to the crankshaft (12), wherein the crankshaft (12) has a drive connection to the camshaft (11) via an adjustable mechanism which is embodied as a triple shaft gear mechanism with a drive shaft which is fixed to the crankshaft, an output shaft which is fixed to the camshaft and an adjustment shaft which has a drive connection to an adjustment motor, wherein a measured value for the crankshaft rotational angle is registered for at least one measuring time for the crankshaft, wherein a measured value for the adjustment shaft rotational angle is digitally recorded for each of at least two measuring times for the adjustment shaft, wherein, for at least one reference time which follows the measuring times for the crankshaft and the adjustment shaft, a value for the rotational angle position of the camshaft (11) in relation to the crankshaft (12) is determined by means of at least one measured value for a crankshaft rotational angle, at least one measured value for an adjustment shaft rotational angle and one gear mechanism characteristic variable of the triple shaft gear mechanism, characterized in that an estimated value for the rotational angle which the adjustment shaft has at the reference time is extrapolated from at least two measured values for the adjustment shaft rotational angle, the time difference between the measuring times for the adjustment shaft, the time difference between the last measuring time for the adjustment shaft and the reference time, and in that the value for the rotational angle position is determined by means of the estimated value of the at least one measured value for the crankshaft rotational angle and the gear mechanism characteristic variable.
2. Method according to Claim 1, characterized in that a value for the angular speed of the adjustment shaft is acquired at least for the respectively last measuring time for the adjustment shaft, and in that the estimated value for the rotational angle which the adjustment shaft has at the reference time is determined from the last measured value for the adjustment shaft rotational angle, the time difference between the reference time and the last measuring time for the adjustment shaft and the angular speed value.
3. Method according to Claim 1 or 2, characterized in that the adjustment motor is an EC motor (14) which has a stator with a winding and a rotor which is connected in a rotationally fixed fashion to the adjustment shaft and at which magnet segments (1..8) are arranged which are offset with respect to one another in the circumferential direction, are alternately magnetized in opposite directions and have tolerances with respect to their positioning and/or the dimensions, in that, in order to register the measured values for the adjustment shaft rotational angle and/or the angular speed values, the position of the magnet segments (1..8) in relation to the stator is detected, in that at least one correction value for compensating the influence of at least one tolerance on the measured values of the adjustment shaft rotational angle is registered, and in that the measured values for the adjustment shaft rotational angle and/or the angular speed values are corrected using the correction value.
4. Method according to one of Claims 1 to 3, characterized in that the position of the magnet segments (1..8) is detected using a measuring device (17) which has a plurality of magnetic field sensors on the stator, which magnetic field sensors are arranged offset with respect to one another in the circumferential direction of the stator in such a way that, per revolution of the rotor in relation to the stator, a number of magnet segment/sensor combinations is run through, and in that for each of these magnet segment/sensor combinations in each case a correction value is acquired, stored and used to correct the measured values for the adjustment shaft rotational angle and/or the angular speed values.
5. Method according to one of Claims 1 to 4, characterized in that the rotor is rotated in relation to the stator in such a way that a number of magnet segment/sensor combinations is run through, that first uncorrected measurement values for the adjustment shaft rotational angle and/or angular speed values are registered for these magnet segment/sensor combinations using the measuring device (17), in that in addition reference values for the adjustment shaft rotational angle and/or the angular speed are registered which have a greater accuracy than the first measured values for the adjustment shaft rotational angle or angular speed values, in that the correction values are determined as correction factors using the first uncorrected measured values for the adjustment shaft rotational angle and/or angular speed values, in that the magnet segment/sensor combinations which are assigned to the first uncorrected measured values for the adjustment shaft rotational angle and/or angular speed values are run through again and in the process second uncorrected measured values for the adjustment shaft rotational angle and/or angular speed values are registered using the measuring device (17), and in that these values are corrected using the previously acquired correction factors.
6. Method according to one of Claims 1 to 5, characterized in that the reference values are formed by virtue of the fact that the first uncorrected measured values for the adjustment shaft rotational angle and/or angular speed values are smoothed by filtering.
7. Method according to one of Claims 1 to 6, characterized in that the rotor is rotated in relation to the stator in such a way that the individual magnet segment/sensor combinations occur at least twice, in that in the process in each case a correction factor for the measured values for the adjustment shaft rotational angle and/or angular speed values is acquired for the individual magnet segment/sensor combinations, in that in each case a mean value is formed from the correction factors acquired for the individual magnet segment/sensor combinations, and in that the mean values which are obtained in this way are stored as new correction factors and the measured values for the adjustment shaft rotational angle and angular speed values are corrected using these correction factors when the magnet segment/sensor combinations are run through again.
8. Method according to one of Claims 1 to 7, characterized in that in each case the arithmetic mean value is formed as a mean value.
9. Method according to one of Claims 1 to 8, characterized in that in each case a sliding mean value is formed as the mean value, preferably in such a way that the weighting with which the correction factors are included in the mean value decreases as the age of the correction factors increases.
10. Method according to one of Claims 1 to 9, characterized in that the sliding mean values F_Neu[i(t-T)] for the individual magnet segment/sensor combinations are determined cyclically according to the formula F_Neu[i(t-T)] = λF_Alt[i(t-T)] + (1-λ)F[i(t-T)], wherein i is an index which identifies the respective magnet segment/sensor combination, t is the time, T is a delay between the actual angular speed and the measured angular speed values, F_Alt[i(t-T)] is the mean value acquired during the last formation of a mean value at the index i and λ is a weighting factor which is greater than 0 and less than 1, and preferably in the interval between 0.7 and 0.9.
11. Method according to one of Claims 1 to 12, characterized

    a) in that the rotor rotates in relation to the stator and the correction factors for the individual magnet segment/sensor combinations are acquired and are stored,

    b) in that the corresponding magnet segment/sensor combinations are then run through again, with a set of new correction factors being acquired,

    c) in that the correction factors of the old correction factor set are interchanged cyclically in relation to those of the new correction factor set, and the correction factor sets are then compared with one another,

    d) in that step c) is repeated until all the interchange combinations of the old correction factor set have been compared with the new correction factor set,

    e) in that the interchange combination at which there is maximum correspondence with the new correction factor set is acquired,

    f) and in that the angular speed values are corrected using the arrangement, assigned to this interchange combination, of the correction values of the old correction factor set.
12. Method according to Claim 11, characterized in that a mean value is formed from each of the correction factors of the old correction factor set and of the new correction factor set which are assigned to one another in the interchange combination at which there is maximum correspondence between the correction factor sets, and said mean value is stored as a new correction factor, and in that the angular speed values are corrected with the correction factor set which is obtained through this formation of mean values.
13. Method according to one of Claims 1 to 12, characterized

    a) in that the rotor is rotated in relation to the stator in such a way that all the magnet segment/sensor combinations are run through at least once,

    b) in that in the process a position measuring signal of the magnet field sensors is generated in such a way that per revolution of the EC motor (14) for each pair of poles of the rotor a number of measurement signal states is run through in each case,

    c) in that a first data record with a number of value combinations which correspond to the number of magnet segment/sensor combinations, composed in each case at least of a correction factor for the respective magnet segment/sensor combination and a measurement signal state which is assigned thereto, is acquired and stored,

    d) in that the corresponding magnet segment/sensor combinations are then run through again, wherein a new second data record with value combinations is acquired and stored,

    e) in that, when there is a deviation between the measurement signal states of the first data record and those of the second data record, the value combinations of the first data record are shifted cyclically in relation to those of the second data record in such a way that the measurement signal states of the data records correspond,

    f) in that the correction factors of the data records which are respectively assigned to one another are then compared with one another,

    g) in that the correction factors of one of the data records is interchanged cyclically in relation to the correction factors of the other data record by a number of steps corresponding to twice the number of magnet field sensors, and the correction factors of the data records which are respectively assigned to one another are then compared with one another,

    h) in that step g) is possibly repeated until all the interchange combinations have been processed,

    i) in that an interchange combination at which there is maximum correspondence between the correction factors of the data records is acquired,

    j) and in that the angular speed values are corrected with the arrangement, assigned to this interchange combination, of the correction values of the first data record.
14. Method according to Claim 13, characterized in that a mean value is formed for each of the correction factors of the first and second data records which are respectively assigned to one another in the interchange combination in which there is maximum correspondence between the correction factors of the data records, and said mean value is stored as a new correction factor, and in that the angular speed values are corrected with the correction factor set which is obtained by this formation of mean values.
15. Method according to one of Claims 1 to 14, characterized in that the fluctuation ranges of the uncorrected angular speed values and of the corrected angular speed values are acquired in a time window and compared with one another, and in that, if the fluctuation range of the corrected angular speed values is greater than that of the uncorrected angular speed values, the correction factors are newly acquired and/or the assignment of the correction factors to the magnet segment/sensor combinations is restored.
16. Method according to one of Claims 1 to 15, characterized in that the correction factors are limited to a predefined value range which is preferably between 0.8 and 1.2.
17. Method according to one of Claims 1 to 16, characterized in that a value for the moment of inertia is determined for the moment of mass inertia of the rotor, in that a current signal I is measured by determining in each case a current value I(k) for the electric current in the winding for the individual measuring times for the adjustment shaft, and in that an estimated value ω_s(k) for the angular speed value ω(k) is determined for the individual angular speed values ω(k), in each case from an angular speed value ω_k(k-1) assigned to an earlier measuring time for the adjustment shaft, from the current signal I and from the value for the moment of inertia, in that a tolerance band which contains the estimated value ω_s(k) is assigned to this estimated value ω_s(k), and in that, if the angular speed value ω(k) is outside the tolerance band, the angular speed value ω(k) is replaced by an angular speed value ω_k(k) which is within the tolerance band.
18. Method according to one of Claims 1 to 17, characterized in that the rotor is loaded with a load torque, in that a load torque signal M_L is made available for the load torque, and in that the estimated value ω_s(k) is determined in each case from the angular speed value ω_k(k-1) which is assigned to the earlier sampling time, the current signal I, the load torque signal M_L and the value for the moment of inertia.
19. Method according to one of Claims 1 to 18, characterized in that the electric voltage which is applied to the winding is measured, and in that the current values I(k) are determined indirectly from the voltage, the impedance of the winding, the angular speed values ω_k(k), which are if appropriate corrected, and an engine constant.
20. Method according to one of Claims 1 to 19, characterized in that the tolerance band is limited by edge values, and in that angular speed values ω(k) which are outside the tolerance band are corrected to the edge value, which is closest to them of the tolerance band.
21. Method according to one of Claims 1 to 20, characterized in that the width and/or position of the tolerance band are/is selected as a function of the angular speed value ω_k(k-1) which is assigned to the earlier measuring time for the adjustment shaft, and is/are preferably reduced as the angular speed rises and/or increased as the angular speed decreases.
22. Method according to one of Claims 1 to 21, characterized in that the width and/or position of the tolerance band are/is selected as a function of the current signal I and are/is preferably increased as the current rises and/or reduced as the current decreases.
23. Method according to one of Claims 1 to 22, characterized in that the current signal I is smoothed by filtering, in particular by forming sliding mean values, and in that the estimated values ω_s(k) for the angular speed values ω(k) are determined using the filtered current signal I.
24. Method according to one of Claims 1 to 23, characterized in that an estimated value for the rotational angle which the crankshaft (12) has at the reference time is extrapolated in each case from at least two measured values for the crankshaft rotational angle, the time difference between the measuring times for the crankshaft rotational angles which are assigned to these measured values and the time difference between the last measuring time for the crankshaft and the reference time, in that the time difference between the reference time and the last measuring time for the crankshaft is acquired, and in that the estimated value is determined from the measured value for the crankshaft rotational angle at the last measuring time for the crankshaft, from the time difference and from the angular speed value.

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