DE102005035881A1 - Method for determining rotational angular position of camshaft of piston engine in relation to crankshaft entails extrapolating assessed value for rotational angle from adjusting shaft rotational angle measurements - 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 The invention relates to a method for determining the angular position the camshaft of a reciprocating internal combustion engine relative to Crankshaft, with the crankshaft via a variable with the camshaft is in drive connection, as a three-shaft gear with a crankshaft-fixed drive shaft, a camshaft-fixed Output shaft and an adjusting shaft is formed, which with a Adjusting motor is in drive connection, wherein for at least a crankshaft measuring time a measured value for the crankshaft rotation angle is detected, where for at least two Verstellwellen measuring times each a measured value for the Verstellwellenendrehwinkel is detected digitally, wherein for at least a reference time after the crankshaft and Verstellwellen measuring times is, based on at least one crankshaft rotation angle measurement, at least a Verstellwellenendrehwinkel measured value and a transmission characteristic of the three-shaft transmission a value for the angular position of the camshaft is determined relative to the crankshaft.

One such method is known in practice. It is as adjusting provided a planetary gear, with the drive shaft a relative rotatably mounted to the camshaft rotatably mounted camshaft gear connected, that over a drive chain is drivingly connected to a crankshaft gear. An output shaft of the variable speed gear is connected to the camshaft and an adjusting shaft with an adjusting motor in drive connection. When the drive shaft is stationary, it lies between the adjusting shaft and the output shaft a predetermined by the adjusting gear ratio before, the so-called stationary gear ratio. When the adjusting shaft turns, enlarges or decreases relative to the direction of rotation of the adjusting relative to the camshaft gear, the gear ratio between the drive and the output shaft, causing the phase angle of the camshaft changed relative to the crankshaft. Compared to a method in which the internal combustion engine operated with constant phase, can by adjusting the phasing a better cylinder filling of the internal combustion engine be achieved, thereby saving fuel, which reduces pollutant emissions and / or the output line of the internal combustion engine can be increased can. To regulate the phase position to a setpoint signal, be first the angles of rotation of the crankshaft and the adjusting shaft by means of inductive sensors are measured and then using the known Fixed transmission ratio an actual value signal for determines the phase angle of the camshaft relative to the crankshaft. At a reference time, in a microprocessor-based electronic control unit an interrupt is triggered, where the measured value for the Verstellwellenendrehwinkel read into a control device and compared with a provided setpoint signal. At the Occurrence of a deviation between the measured value and the setpoint signal the controller controls the EC motor so that the deviation is reduced. The measurement of the Verstellwellenendrehwinkels takes place with the help of magnetic field sensors, which determine the location of the circumference of the EC motor rotor digitally detect arranged magnetic segments. Due to digitization the measured values and the deviating from the Verstellwellen-measuring times However, at the time of measurement, measurement inaccuracies occur to lead, that the measured relative angular position of the camshaft a sawtooth-shaped vibration around the actual Performs angular position. This has a detrimental effect on the control accuracy and has as well also an elevated one Energy absorption of the EC motor result.

It There is therefore the task of a method of the aforementioned To create a kind of accurate determination of the angular position of the Camshaft relative to the crankshaft allows.

These Task is solved by that 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 an estimate for the Angle of rotation which the adjusting shaft has at the reference time, is extrapolated, and that based on the estimated value of at least one Crankshaft rotation angle measured value and the transmission characteristic value for the Angular position is determined.

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 ent speaking. The inventive method thus enables a high precision in the determination of the phase position and a low power consumption of the adjusting motor.

at a preferred embodiment The invention is at least for the last Verstellwellen measuring time a value for the angular velocity determines the adjustment, wherein the estimated value for the angle of rotation, the adjusting shaft at the reference time, from the last Verstellwellenendrehwinkel measured value, the time difference between the reference time and the last Verstellwellen measuring time and the angular velocity value. The Verstellwellenendrehwinkel measured value at the reference time Thus, by linear interpolation from the last Verstellwellenendrehwinkel measured value determined 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 these angular velocity values assigned measuring times are calculated.

at an advantageous embodiment the invention, the adjusting motor is an EC motor, which is a stator with a winding and a rotatably connected to the adjusting shaft runner has, at the circumferentially offset from each other, alternately in opposite directions magnetized magnet segments are arranged, the tolerances in terms of their positioning and / or their dimensions, wherein for detecting the Verstellwellenendrehwinkel measured values and / or the angular velocity values the position of the magnet segments is detected relative to the stator, wherein at least one correction value to compensate for the influence of at least one tolerance on the Verstellwellenendrehwinkel measured values is detected, and wherein the Verstellwellenendrehwinkel measured values and / or corrects the angular velocity values using the correction value become. This embodiment is based on the realization that in a multiple pass a tolerant magnetic segment of the rotor at a fixed to Stator arranged magnetic sensor, using the magnetic sensor detected position measurement signal for the corresponding magnet segment always the same each time the magnetic sensor passes, Having caused by the tolerance of the magnet segment error. This error is determined by measurement or otherwise, to then determine a correction value with which the Verstellwellenendrehwinkel measured values for a later Time corrected when the relevant magnet segment the magnetic field sensor happens again. Thus, one through a Tolerance of a magnetic segment caused measurement inaccuracy be easily corrected in the speed signal. there is it even possible this Correction online at the currently measured speed value perform, without that between the corrected speed value and the uncorrected one Speed value a time delay occurs.

Advantageous is when the location of the magnet segments by means of a measuring device is detected, which has a plurality of magnetic field sensors on the stator, arranged offset in the circumferential direction of the stator to each other are that per turn of the runner a number of magnetic segment-sensor combinations relative to the stator is going through, and if for each of these magnetic segment-sensor combinations each have a correction value determined, stored and to correct the Verstellwellenendrehwinkel measured values and / or the angular velocity values are used. The phasing of the Camshaft relative to the crankshaft can then be adjusted with even greater precision become. The number of magnet segment sensor combinations corresponds preferably the product of the number of magnetic field sensors and the number of magnetic poles of the rotor.

at A preferred embodiment of the invention is the runner such relative to the stator twisted that a number of magnetic segment sensor combinations is passed through, with the help of the measuring device for this Magnetic segment sensor combinations first uncorrected variable shaft angle measurement values and / or angular velocity values are detected, with additional reference values for the adjustment shaft rotation angle and / or detecting the angular velocity having greater accuracy as that the first Verstellwellenendrehwinkel measured values or angular velocity values, using the first uncorrected Verstellwellenendrehwinkel measured values or angular velocity values the correction values as correction factors being determined, wherein the first uncorrected Verstellwellenendrehwinkel measured values or angular velocity values associated magnetic segment sensor combinations run through again and second with the help of the measuring device uncorrected adjustment shaft rotation angle measurement values or angular velocity values be detected, and these values using the previously determined Correction factors are corrected. The correction values will be so determined in the form of correction factors, resulting in a correction the measurement errors caused by the tolerances of the magnet segment is possible at different speeds. The reference signal can be a measuring signal, for example, in the manufacture of the EC motor with the help of an additional Position measuring device is detected. The reference signal can also be a Speed and / or an integrated acceleration signal a Be wave, which is coupled to the EC motor.

at an expedient embodiment According to the invention, the reference values are formed by the fact that the first uncorrected Verstellwellenendrehwinkel measured values or angular velocity values smoothed by filtering become. This can be an additional Sensor for measuring the reference signal can be saved.

Advantageous is when the runner is rotated relative to the stator that the individual magnetic segment sensor combinations occur at least twice when doing so for the individual magnet segment sensor combinations each a correction factor for the Verstellwellenendrehwinkel measured values or angular velocity values is determined, if from the for the individual magnetic segment sensor combinations determined correction factors an average is formed, and if so obtained Mean values stored as new correction factors and the Verstellwellenendrehwinkel measured values or angular velocity values in a new run the magnetic segment sensor combinations be corrected with the help of these correction factors. The single ones Magnetic segment sensor combinations are preferred as possible often go through what happens with an EC motor for an electronic camshaft adjustment easily possible is because this is during the operation of the internal combustion engine is constantly rotating.

at an embodiment In the invention, the mean value is the arithmetic mean value educated. All go for the Averaging used correction factors of the same weight in the mean value.

at a preferred embodiment In the invention, the average value is a moving average formed, preferably such that the weight with which the correction factors into the mean, with increasing age of correction factors decreases. New correction factors are therefore taken more into account in the mean value as correction factors that are assigned to an earlier date. If an error occurs, it will cause a magnetic segment-sensor combination not recognized and thus the already determined correction factors assigned to the wrong magnet segments, the wrong affects Correction factor allocation only short-term on the correction of the speed signal, i.e. the wrong correction factors are "forgotten" relatively quickly.

It is advantageous if the moving average values F _New [i (t-T)] for the individual magnetic segment sensor combinations are cyclically calculated according to the formula F _New [i (t-T)] = λ F _Alt [i (t-T) ] + (1-λ) F [i (t-T)], 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 (t-T)] is the mean determined at the last averaging at index i, and λ is a forgetting factor that is greater than zero and less than 1, and is 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).

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

• a) the rotor is rotated relative to the stator and the correction factors for the individual magnetic segment sensor combinations are determined and stored,
• b) thereafter the respective magnetic segment-sensor combinations are run through again, whereby a set of new correction factors is determined,
• 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,
• 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,
• e) that the commutation combination at which a maximum match with the new correction factor set occurs is determined,
• 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 she during the early heren switch-on phase were determined.

Possibly can the correction factors even under ideal conditions during production of the EC motor are determined, preferably in a final stage the production.

Advantageous is when out of the case of the combination of commutation, in which one maximum match between the correction factor sets occurs, respectively mutually associated correction factors of the old correction factor set and the new correction factor set each formed an average value and saved as a new correction factor, and when with the the correction factor set obtained by this averaging Angular velocity values are corrected. So it will be both the correction factors of the first record as well as the second Record taken into account in the correction of the angular velocity values.

• a) dass der Läufer derart relativ zu dem Stator verdreht wird, dass alle Magnetsegment-Sensor-Kombinationen mindestens einmal durchlaufen werden,
• 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,
• 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,
• d) dass danach die entsprechenden Magnetsegment-Sensor-Kombinationen erneut durchlaufen werden, wobei ein neuer, zweiter Datensatz mit Wertekombinationen ermittelt und gespeichert wird,
• 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,
• f) dass danach die jeweils einander zugeordneten Korrekturfaktoren der Datensätze miteinander verglichen werden,
• 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,
• h) dass Schritt g) gegebenenfalls wiederholt wird, bis alle Vertauschungskombinationen bearbeitet wurden,
• i) dass eine Vertauschungskombination, bei der eine maximale Übereinstimmung zwischen den Korrekturfaktoren der Datensätze auftritt, ermittelt wird,
• 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

• a) that the rotor is rotated relative to the stator such that all magnetic segment sensor combinations are traversed at least once,
• 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
• 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,
• 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,
• 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,
• f) that thereafter the respective mutually associated correction factors of the data sets are compared with each other,
• 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,
• h) if necessary, step g) is repeated until all commutation combinations have been processed,
• i) that a permutation combination in which a maximum match between the correction factors of the data sets occurs is determined,
• 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.

By these measures can with relatively few interchange operations and thus correspondingly little time expenditure, the assignment of the correction factors be restored to the magnetic segment sensor combinations.

there is it even possible that from the at the permutation combination, where a maximum match between the correction factors of the records occurs, each other associated correction factors of the first and second data set in each case a mean value is formed and stored as a new correction factor and that with the correction factor set obtained by this averaging Angular velocity values are corrected. Thus, both the correction factors of the first record as well as the second Record 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 made for example, by cyclically swapping the correction factors restored.

Conveniently, the correction factors are set to a predetermined value range limited, which is preferably between 0.8 and 1.2. Thereby can Runaway in the corrected speed signal, by implausible, outside caused by the predetermined value range lying correction factors, repressed become.

In an advantageous embodiment of the invention, an inertia moment value for the mass moment of inertia of the rotor is determined, wherein a current signal I is detected by a respective current value I (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 ω (k) is outside the tolerance band, the angular velocity value ω (k) by one within the Tolerance band located angular velocity value ω _k (k) is replaced. Thus, angular velocity values ω (k) which are 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: J · dω / dt = K t · I

J is the mass moment of inertia of the rotor, ω 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:

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 ω (k) can be derived from the estimated value ω _s as follows be determined: ω HighLim (k) = ω s + Δω border = ω (k-1) + T K t · I (k-1) / J + Δω border ω LowLim (k) = ω s - Δω border = ω (k-1) + T K t · I (k-1) / J - Δω 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 ω (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: J · dω / dt = K t ·IN THE L

ωHighLim(k)) = ωs + ΔωGrenz = ω(k–1) + T/J [Kt·I(k–1) – ML(k–1)] + ΔωGrenz ωLowLim(k) = ωs – ΔωGrenz = ω(k–1) + T/J [Kt·I(k–1) – ML(k–1)] – ΔωGrenz 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:

ω HighLim (k)) = ω s + Δω border = ω (k-1) + T / J [K t · I (k-1) - M L (k-1)] + Δω border ω LowLim (k) = ω s - Δω border = ω (k-1) + T / J [K t · I (k-1) - M L (k-1)] - Δω border

In an expedient embodiment of the invention, the voltage applied to the winding electrical voltage is detected, wherein the current values I (k) indirectly from the voltage, the impedance of the winding, the optionally corrected speed measurement value ω (k) and an engine constant K _{e is} determined. The corresponding system equation is: U = R A · I + L A · Dl / dt + K e · ω 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.

at an expedient embodiment The invention relates to the width and / or position of the tolerance band in dependence selected from the current signal I. and preferably increased with increasing current and / or decreasing Electricity reduced. It is assumed that with a large winding current the runner usually accelerates, so that the speed accordingly increases. The width and / or position of the tolerance band is so on the expected due to the energization of the winding speed changes of the runner customized.

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 ω (k) are determined with the aid of the filtered current signal I.

at an advantageous embodiment each of the invention is made up of at least two crankshaft rotation angle measurement values, the time difference between the values assigned to these measured values Crankshaft rotation angle measuring times and the time interval between the last crankshaft measuring time and the reference time estimated value for the Rotation angle that the crankshaft has at the reference time, extrapolated, with the time difference between the reference time and the last crankshaft measuring time is determined, and wherein the estimate from the crankshaft rotation angle measurement at the last crankshaft measurement time, the time difference and the angular velocity value is determined. By This measure can be used in combination with the extrapolation of the calibration wave measurement times a very high precision be achieved when adjusting the phase angle.

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

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,

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,

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,

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

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

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

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 rotational angle or phase angle of the camshaft 11 a reciprocating internal combustion engine relative to the crankshaft 12 has an adjusting gear 13 on, which is designed as a three-shaft transmission 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 1 It can be seen that for measuring the crankshaft rotation angle, an inductive sensor 15 is provided, which the tooth flanks of one consisting of a magnetically conductive material on the crankshaft 12 arranged sprocket 16 detected. One of the tooth spaces or teeth of the sprocket 16 has a greater width than the other tooth gaps or teeth and serves as a reference mark. Passing the reference mark on the sensor 15 the measured value for the crankshaft rotation angle is set to a starting value. Thereafter, the reading will be until the reference mark passes the sensor again 15 tracked with each detection of a tooth flank. 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.

The adjusting motor is an EC motor 14 provided, which has a rotor, on the circumference of a series of magnet sections alternately magnetized in opposite directions is arranged, which interact magnetically via an air gap with teeth of a stator. 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 using a measuring device 17 detected, which has on the stator a plurality of magnetic field sensors A, B, C, which are arranged offset from one another in the circumferential direction of the stator, that per revolution of the rotor a number of magnetic segment sensor combinations is traversed. The reference value generator for the camshaft rotation angle is a Hall sensor 18 provided with one on the camshaft 11 arranged trigger wheel 19 interacts. If the Hall sensor 18 a flank of the trigger wheel 19 detected, 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: ε Section = ε KW (t TrigNW )

The rotational angle 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 basic transmission equation of the three-shaft transmission:

In this case, i _{g is} the stationary gear ratio between the camshaft 11 and the adjusting shaft:

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 time, an interrupt is then triggered in the operating program of the control unit, 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} . This interrupt will also be referred to as a cyclic interrupt below.

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°:

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:

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 °:

As in 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. The EC motor rotates stationary 14 exactly twice as fast as the crankshaft 12 , As a rule, the times at which the cyclic interrupt occurs differ from the times at which the magnetic segment-sensor combinations change. In 2 For example, nine changes in the magnetic segment-sensor combinations occur within eight interrupt cycles, ie, for each interrupt cycle, the electric motor covers an angle of (9/8) x 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.

Around the height these jumps to reduce or even completely avoid them is through Extrapolation of at least two Verstellwellenendrehwinkel measured values an estimate for the Angle of rotation, which has the adjusting shaft at reference time, the lies after the Verstellwellen-measuring times. As reference points On the one hand are the times when the camshaft interrupts occur, and on the other hand, the times at which the cyclic Interrupts triggered are elected.

The extrapolation will be explained below 3 explained. At time t _TrigNW of No Ckenwellen interrupt are the Verstellwellenendrehwinkelwert corresponding count N _TrigNW the measuring device 17 , the time Δt _TrigNW and the speed ω _{Em, TrigNW} (signed) at 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.

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 _i can be determined more accurately than before: φ Em, TrigNW = N TrigNW · δ em + Δt TrigNW · ω Em, TrigNW (2.1) φ Em, ti = N ti · δ em + Δt i · Δ Em, ti (2.2)

The differential angle necessary for the calculation of the phase angle to the current ECU interrupt t _i is accordingly: Δφ Em, ti = φ Em, ti - φ Em, TrigNW = (N ti - N TrigNW ) · Δ em + [Δt i · ω Em, ti - Δt TrigNW · Δ Em, TrigNW ]

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: ω em = S · δ em / .DELTA.t Hall ,

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. However, it should be noted that the mean value can only be calculated with a time delay, so that when the EC motor accelerates 14 this error is included in the extrapolation. In the ECU interrupt, the current speed ω _{Em of} the EC motor 14 also calculated for the control of the phase angle.

The following is based on 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 4 As shown, the rotor has eight magnet segments 1 .. 8th placed in a grid of 45 ° in the circumferential direction of a support member 9 at which the magnet segments 1 .. 8th are fixed, offset from one another. The magnet segments 1 .. 8th 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 4 this is exemplified for a rotor with p = 4 pole pairs. On the through the magnet segments 1 .. 8th the magnetization changes its direction 8 times per revolution. As already mentioned, the magnet segments have 1 .. 8th both in terms of their location and in terms of their dimensions in the circumferential direction tolerances. The mechanical angle α between mutually corresponding points of adjacent magnetic segments 1 .. 8th can therefore deviate from the setpoint 180 ° / p (here: 45 °). The direction of rotation of the runner is in 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 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 5 is a portion of the output signals A ', B', C 'of the sensors A, B, C together set Verstellwellenendrehwinkelsignals for a clockwise rotation in the direction of arrow Pf shown graphically. 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 a magnet segment forming a north pole 1 .. 8th opposite. In a corresponding manner, the output signal A ', B', C 'assumes the logic value 0, if the respective sensor A, B, C is a magnetic segment forming a south pole 1 .. 8th opposite.

To the assignment of the individual values of an output signal to the respective magnetic field section just moved past the relevant sensor A, B, C 1 .. 8th to clarify, the reference value of the relevant magnetic field section is in each case at the output signal values 1 .. 8th played. In 5 are below the output signals on the abscissa each of the magnetic rotation angle φ _magnetic and the mechanical rotation angle φ _magnetically 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. The control unit is only the output signals A ', B' and C 'known, but not which magnetic segments 1 .. 8th just past the sensors A, B, C are moved past.

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

By counting the change at which the position measurement signal changes its value becomes the total angle of rotation of the runner certainly. Starting from a starting value, the total angle is added incremented every 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: ω = π / (m × p × Δt) [rad / s].

Due to the tolerances of the magnet segments 1 .. 8th is the thus determined speed signal ω _{measurement, i} afflicted with errors that cause, for example, at a constant actual speed of the rotor to the fact that the speed signal has jumps.

In the control unit the magnet segment sensor combinations are numbered 1 to 2 * m * p, so that the count, hereafter referred to as "Index i "is designated ramping up and on reaching 2 · m · p then jumps to 1 When the EC motor is switched on, the index i will open set a start value, e.g. to the value 1.

For each magnetic segment-sensor combination, a correction factor F _Adap [i] is now determined, which via the index i to the corresponding magnet segment 1 .. 8th is assigned. This correction factor F _Adap [i] corresponds to the ratio between the rotational speed value ω _{Mess, i} , which was determined by means of the Verstellwellenendrehwinkelsignal for the i-th magnetic segment-sensor combination, and a reference speed value ω _Ref , which is assumed that a greater accuracy than the 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: ω Corr, i = ω Measuring, i / F Adap [I],

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} ent first, the measured speed ω _{measurement, 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, derjeweils 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), FTrue[i] = ωMess,i(t)/ωTrue(t)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: F[i(t–T)] = ωMess,i(t–T)/ωRef(t).
• 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: FNeu[i(t–T)] = λ FAlt[i(t–T)] + (1–λ) F[i(t–T)]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,i(t) durchgeführt. Mit dem bis dahin adaptierten Korrekturfaktor F[i] wird der Messwert korrigiert: ωKorr,i = ωMess(t)/F[i].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 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 saved. 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 is adapted in each case at the end to the sequence for calling the next sequence.
• B: calculation of the uncorrected rotational speed ω _{meas, i} = π / (m × p × Δt).
• C: Filtering the uncorrected speed: Since the true speed ω _{True is} unknown, the reference signal for the speed 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 (t-T). Where T is the delay time of the filter, which differs from the type and order of the filter.
• D: Checking 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), F true [i] = ω Measuring, i (T) / ω true (T) 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: F [i (t-T)] = ω Measuring, i (T-T) / ω Ref (T).
• F: Averaging for the Correction Factor: The correction factor F still has a certain inaccuracy since the reference speed 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: F New [i (t-T)] = λ F Old [i (t-T)] + (1-λ) F [i (t-T)] 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, i} (t). With the hitherto adapted correction factor F [i], the measured value is corrected: ω Corr, i = ω measuring (T) / F [i]. 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, in order to access these values as historical 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. Stands another measurement signal available from which can be closed to the actual speed, so this can also be used.

at Turn off the EC engine and the controller Device will learn the 2 · p · m Correction factors written in a nonvolatile data memory of the controller. Since, at the beginning of the adaptation, the index i in the case of a magnetic segment-sensor combination, the just happened was active, at a random selected Start value set and this magnet segment sensor combination after the Restart the control unit first is not known, the assignment of correction factors to the Magnetic segment sensor combinations and checks when detecting a incorrect assignment can be corrected 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.

in the Data memory of the controller the correct order of the 2 m (= 6) successive position measurement signal states is stored. This is compared with the order of the states of the position measurement signal. If a deviation is detected, this error will occur next Call of the sequence eliminated. The change of the magnetic segment sensor combinations is that within ± m changes clearly. Is sure that while the disorder the direction of rotation of the runner can be maintained even (2m-1) Updates are corrected.

The quality the adaptation is monitored by that the fluctuation range of the uncorrected and the corrected Speed over again a certain time window are compared. varies the corrected speed stronger as the uncorrected speed, an erroneous assignment is concluded. The assignment is then either restored or the correction factors are set to 1.

at Restoring the mapping assumes that the number sequence of the 2 · p · m correction factors represents a kind of characteristic signature. If you adapt one new set of correction factors, these must be a very similar Number sequence, however, the new sequence of numbers compared to the previous sequence of numbers may be shifted. To restore The assignment therefore becomes the old sequence of numbers 2 · p · m times cyclically shifted and after each shift step with the previous one Number sequence compared. In the case of an exchange or displacement combination, at the greatest match between the old and the previous sequence of numbers occurs Suppose that the numerical values of the old sequence of numbers correct the magnet segment-sensor combinations assigned. With this assignment, the correction of the Speed signal and / or further adaptation 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 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 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 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 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 magnet segment sensor combinations, each consisting of at least one correction factor for the relevant magnet segment sensor combination and a measurement signal state associated therewith, is determined and stored. An embodiment of such a record for an EC motor 4 with three magnetic field sensors and three pole pairs is in the upper half of 7 shown graphically.
• • Thereafter, the magnetic segment-sensor combinations for which the correction factors have been determined are run through again, whereby a new, second data set with value combinations is determined and stored. This second record is in 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 7 This can be achieved by shifting the value combinations of the old adaptation by three positions cyclically to the right.
• • Thereafter, the respectively 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 record in 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 respective mutually associated correction factors of the data sets compared to each other. This step is repeated until all commutation combinations have been edited.
• • Thereafter, the commutation combination, at which a maximum match between the correction factor sets is achieved, is determined. With this permutation combination, an average value is respectively formed from the mutually associated correction factors of the correction factor sets and stored as a new correction factor. The speed correction signal is then corrected with the new correction factors determined in this way.

It So it does not have to be 2 · p · m times be pushed. It just has to be found out which of the p magnetic periods best fits. During the time in which the new correction factors are adapted, the corrected speed either with the factor 1 or with the hitherto newly adapted Correction factors calculated.

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 of the magnetic field sensor A

B '

output the magnetic field sensor B

C '

output the magnetic field sensor C

pf

direction of rotation

Claims (24)

Method for determining the angular position of the camshaft ( 11 ) of a reciprocating internal combustion engine relative to the crankshaft ( 12 ), the crankshaft ( 12 ) via an adjusting gear with the camshaft ( 11 ) is in driving connection, which is designed as a three-shaft gear with a crankshaft fixed drive shaft, a camshaft fixed output shaft and an adjusting shaft, which 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 A measured value for the Verstellwellenendrehwinkel digitally is detected, wherein for at least one reference time, which is after the crankshaft and Verstellwellen measuring times 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 Angular position of the camshaft ( 11 ) relative to the crankshaft ( 12 ), characterized in that 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 point, an estimated value for the angle of rotation, which has the adjustment at the reference time, extrapolated and in 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. A method according to claim 1, characterized in that a value for the angular velocity of the adjusting is determined at least for the last Verstellwellen measuring time, and that the An estimated value for the rotation angle that the adjustment shaft has at the reference time from the last adjustment shaft rotation angle measurement, the time difference between the reference time and the last adjustment shaft measurement time, and the angular speed value. A method according to claim 1 or 2, characterized in that the adjusting motor is an EC motor ( 14 ) having a stator with a winding and a rotatably connected to the adjusting shaft rotor, at the circumferentially offset from each other, magnetized in opposite directions magnetized magnet segments ( 1 .. 8th ), which have tolerances with respect to their positioning and / or their dimensions, that the position of the magnet segments () can be arranged to detect the adjustment shaft rotation angle measurement values and / or the angular velocity values. 1 .. 8th ) is detected relative to the stator, that at least one correction value for compensating the influence of at least one tolerance on the Verstellwellenendrehwinkel measured values is detected, and that the Verstellwellenendrehwinkel measured values and / or the angular velocity values are corrected by means of the correction value. Method according to one of claims 1 to 3, characterized in that the position of the magnetic segments ( 1 .. 8th ) by means of a measuring device ( 17 ) is detected, which has on the stator a plurality of magnetic field sensors which are arranged offset to one another in the circumferential direction of the stator, that per revolution of the rotor relative to the stator a number of magnetic segment sensor combinations is traversed, and that for each of these Magnetsegment- Sensor combinations each detected a correction value, stored and used to correct the Verstellwellenendrehwinkel measured values and / or the angular velocity values. Method according to one of claims 1 to 4, characterized in that the rotor is rotated relative to the stator so that a number of magnetic segment sensor combinations is traversed that by means of the measuring device ( 17 ) for these magnetic segment sensor combinations first uncorrected Verstellwellenendrehwinkel measured values and / or angular velocity values are detected, that additionally 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, in that the correction values are determined as correction factors with the aid of the first uncorrected adjustment shaft rotation angle measurement values or angular velocity values, and that the magnet segment sensor combinations assigned to the first uncorrected adjustment shaft rotation angle measurement values or angular velocity values pass through again using the measurement device ( 17 ) second uncorrected Verstellwellenendrehwinkel measured values or angular velocity values are detected, and that these values are corrected by means of the previously determined correction factors. Method according to one of claims 1 to 5, characterized that the reference values are formed by the first uncorrected Verstellwellenendrehwinkel measured values or angular velocity values smoothed by filtering become. Method according to one of claims 1 to 6, characterized that the runner is rotated relative to the stator that the individual magnetic segment sensor combinations At least two times that occur for the individual magnet segment sensor combinations each a correction factor for the Verstellwellenendrehwinkel measured values or angular velocity values is determined that from the for the individual magnetic segment sensor combinations determined correction factors in each case an average value is formed, and that the thus obtained Mean values stored as new correction factors and the Verstellwellenendrehwinkel measured values or angular velocity values in a re-run through the magnetic segment sensor combinations be corrected with the help of these correction factors. Method according to one of claims 1 to 7, characterized that the mean value is formed in each case the arithmetic mean value becomes. Method according to one of claims 1 to 8, characterized that a moving average is formed as the mean value in each case, preferably such that the weight with which the correction factors into the mean, with increasing age of correction factors decreases. Method according to one of Claims 1 to 9, characterized in that the moving average values F _New [i (t-T)] for the individual magnet segment-sensor combinations are cyclic according to the formula F _New [i (t-T)] = λ F _Alt [i (t-T)] + (1-λ) F [i (t-T)] 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 (t-T)] of the last average at the index i average and λ mean a forgetting factor that is greater than zero and less than 1, and preferably in the interval between 0.7 and 0.9. Method according to one of claims 1 to 12, characterized that a) the runner rotated relative to the stator and the correction factors for the individual Magnetic segment sensor combinations are determined and stored, b) that thereafter the corresponding magnet segment sensor combinations be run again, with a set of new correction factors is determined c) that the correction factors of the old correction factor set cyclically reversed relative to those of the new correction factor set and the correction factor sets then compared with each other, d) that step c) is repeated until all commutation combinations of the old correction factor set compared with the new correction factor set, e) that the permutation combination, where a maximum match with the new correction factor set, it is determined f) and that associated with the arrangement associated with this permutation combination the correction values of the old correction factor set the angular velocity values Getting corrected. Method according to claim 11, characterized in that that from the at the permutation combination, where a maximum match between the correction factor sets occurs, each associated correction factors of the old Correction factor set and the new correction factor set respectively an average is formed and stored as a new correction factor and that with the one obtained by this averaging Correction factor set the angular velocity values are corrected. Method according to one of claims 1 to 12, characterized in that a) that the rotor is rotated relative to the stator so that all magnetic segment sensor combinations are traversed at least once, b) that while a position measurement signal of the magnetic field sensors is generated such that per revolution of the EC motor ( 14 ) for each pole pair of the rotor in each case a number of measurement signal states is passed through, c) that a first data set with a number of magnetic segment sensor combinations corresponding number value combinations, each consisting at least of a correction factor for the respective magnetic segment sensor combination and one of these associated measurement signal state, is determined and stored, d) that thereafter the corresponding magnetic segment sensor combinations are run through again, wherein a new, second set of data with combinations of values is determined and stored, e) that at a deviation between the measurement signal Conditions of the first and those of the second data set, the value combinations of the first data set are shifted cyclically relative to those of the second data set such that the measurement signal states of the data sets match; f) that thereafter the respective mutually associated correction factors of the data sets are compared g) that the correction factors of the 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, h) that step g) optionally i) that a permutation combination in which a maximum correspondence between the correction factors of the data sets occurs is determined, j) and that with the arrangement of the correction values of the first data set associated with this permutation combination the angular velocity values are corrected. Method according to claim 13, characterized in that that from the at the permutation combination, where a maximum match between the correction factors of the records occurs, each other associated correction factors of the first and second data set in each case a mean value is formed and stored as a new correction factor and that with the correction factor set obtained by this averaging the angular velocity values are corrected. Method according to one of Claims 1 to 14, characterized in that the fluctuation ranges of the uncorrected angular velocity values and the corrected angular velocity values are determined in a time window and compared with one another, and 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 newly determined and / or the assignment of the correction factors to the Magnetseg ment-sensor combinations is restored. Method according to one of claims 1 to 15, characterized that the correction factors limited to a predetermined range of values which is preferably between 0.8 and 1.2. Method according to one of claims 1 to 16, characterized in that an inertia moment value for the mass moment of inertia of the rotor is determined that a current signal I is detected by a respective current value I (k) for the electrical current in the winding is determined that for the individual angular speed values ω (k) each comprise a a previous adjustment shaft measurement time associated angular speed value ω _k (k - 1), the current signal I and the moment of inertia value, an estimated value ω _s (k) for the angular speed value ω (k ), it is determined that this tolerance value ω _s (k) is assigned a tolerance band in which the estimated value ω _s (k) is included, and that in case the angular velocity value ω (k) is outside the tolerance band, the angular velocity value ω (k) is replaced by an angular velocity value ω _k (k) within the tolerance band. Method according to one of claims 1 to 17, characterized in that the rotor is loaded with a load torque, that for the load torque, a load torque signal M _{L is} provided, and that the estimated value ω _s (k) respectively from the earlier sampling time associated angular velocity value ω _k (k-1), the current signal I, the load torque signal M _L and the moment of inertia value is determined. Method according to one of claims 1 to 18, characterized in that the electrical voltage applied to the winding is detected, and that the current values I (k) indirectly from the voltage, the impedance of the winding, the optionally corrected angular velocity values ω _k (k) and an engine constant. Method according to one of claims 1 to 19, characterized that the tolerance band is limited by boundary values, and that angular velocity values ω (k), outside of the tolerance band, to the nearest edge value of the tolerance band Tolerance bands are corrected. Method according to one of claims 1 to 20, characterized in that the width and / or position of the tolerance band in dependence on the previous Verstellwellen measuring time associated angular velocity value ω _k (k - 1) is selected and preferably reduced with increasing angular velocity and / or is increased with decreasing angular velocity. Method according to one of claims 1 to 21, characterized that the width and / or position of the tolerance band depending on selected from the current signal I. is and preferably increased and / or increased with increasing current is reduced with decreasing current. Method according to one of Claims 1 to 22, characterized in that the current signal I is smoothed by filtering, in particular by moving averaging, and in that the estimated values ω _s (k) for the angular velocity values ω (k) are filtered with the aid of the filtered current signal I be determined. Method according to one of claims 1 to 23, characterized in that in each case from at least two crankshaft rotation angle measured values, the time difference between the crankshaft rotation angle measuring times associated with these measured values and the time interval between the last crankshaft measuring time and the reference time an estimated value for the rotation angle the crankshaft ( 12 ) at the reference time point, extrapolation is made that the time difference between the reference time and the last crankshaft measuring time is determined, and that the estimated value is determined from the crankshaft rotational angle measured value at the last crankshaft measuring time, the time difference and the angular speed value.