EP0933525B1 - Cylinder recognition apparatus and method for a combustion engine - Google Patents

Description

The present invention relates to a device and a Method for cylinder recognition in an internal combustion engine (hereinafter also referred to briefly as a motor) according to the features of the preamble of claim 1 and 23 respectively.

Such a device is known from WO 89 08778 A.

In modern motor vehicles, engine management takes place, i.e. the control, regulation and monitoring of the essentials Functions of the engine, usually using a Control unit with a computing device.

In particular, the ignition and fuel injection can be controlled jointly and coordinated, whereby the respective operating state of the engine can be recorded precisely and in ignition timing and fuel sizing must be taken into account

One from the computer device for controlling the ignition and fuel injection related important information the position of the crankshaft. Usually is a Crankshaft sensor provided for detecting the crankshaft position. This crankshaft sensor is, for example, an inductive one Encoder that provides a signal for the speed as well Signal for at least one selected crankshaft position outputs. Usually the selected crankshaft position is the top dead center (TDC) of one or more specific cylinders.

With ignition systems with static ignition high voltage distribution with Individual coils, the computer device needs an additional one Information about the position of the camshaft so that the Ignition coil of the cylinder that is currently in or near the TDC of the work cycle is located, can be controlled. Otherwise, the ignition coil could be undesirable the cylinder that is currently in or near the TDC of the exhaust stroke is controlled.

The position of the camshaft is usually determined by means of a camshaft sensor, which for example then emits a signal when the camshaft is in a Position in which a particular cylinder is at the top of its Work cycle is. This known method is also called cylinder one detection designated.

From the combination of the signals from the crankshaft sensor and of the camshaft sensor can the ignition timing and injection timing all cylinders in a unique way be calculated by the computing device.

The specified method according to the prior art has the Disadvantage that two expensive sensors and one accordingly complex wiring is required.

The object of the present invention is a device and a method for cylinder recognition in an internal combustion engine to create, there is no additional camshaft sensor requirement.

This object is achieved by the subject matter of the claim 1 solved, that is, by a device for cylinder detection in an internal combustion engine with a crankshaft sensor device for detecting a crank angle and a predetermined one Crankshaft position and output corresponding Crank signals; an ignition device for igniting the respective Cylinder of the internal combustion engine by generating corresponding ones High voltage pulses in response to corresponding control signals; a control device for receiving the crank signals and outputting the control signals to the ignition device in dependence of at least the crank signals; being the control device is designed so that it is in a cylinder detection phase when receiving a crank signal corresponding to one predetermined crank position to generate a control signal a high-voltage pulse with a predetermined achievable Outputs amplitude in at least one specific cylinder; the predetermined amplitude being smaller than that for ignition in the Working cycle is necessary amplitude; an ignition detection device for detecting whether and / or at which ignition voltage the particular cylinder by the high voltage pulse has been fired and outputting a corresponding ignition detection signal; and a cylinder detection device for Determine whether the particular cylinder is in the predetermined crank position is in his work cycle based at least the ignition detection signal.

According to the invention, the predetermined amplitude is therefore less than the amplitude required for ignition in the work cycle. This has the advantage that no additional tax expense for setting the size of the amplitude of the high-voltage pulses necessary is. In this case, the ignition detection device preferably designed such that they detects the ignition voltage of the particular cylinder. The ignition detection signal is then either the detected ignition voltage itself or a signal that can be clearly derived from it.

This object is also achieved by the one specified in claim 23 Method solved, that is, by a method for cylinder detection in an internal combustion engine with the steps: detection a crank angle and a predetermined crankshaft position and outputting corresponding crank signals; Produce a high-voltage pulse with a predetermined achievable Amplitude in at least one particular cylinder when it is detected a predetermined crank position during a cylinder detection phase; Detect whether and / or at which ignition voltage the particular cylinder by the high voltage pulse has been fired and outputting a corresponding ignition detection signal; and determining whether the particular cylinder is in the predetermined crank position in its working stroke on at least the ignition detection signal.

Preferred developments are the subject of the dependent claims.

The principle of the present invention is based on the fact that Ignition voltage at a predetermined crank position, which on or near the TDC of the cylinder in question depends on the pressure prevailing in the cylinder. So is the ignition voltage at 1 bar typically 5 kV, while at about 5-7 bar is typically about 13-20 kV. The listed Pressures and ignition voltages can differ in two Adjust the cylinders of an engine when the a cylinder just at or near the TDC of its exhaust stroke (Valves are open) and the other cylinder is straight at or near the TDC of his work cycle (valves are closed).

Therefore, by detecting the different ignition voltages can be determined which of the cylinders in the work cycle is located, and accordingly the firing order is determined be without the need for the usual camshaft sensor.

First of all, there is the possibility of recording that the high voltage pulse supplied in the cylinder detection phase is a normal high voltage pulse, i.e. on High voltage pulse, the amplitude of which for ignition in the working cycle reach the necessary size of typically about 13 kV can. In this case the actual ignition voltage recorded and the result for cylinder recognition evaluated.

Second, the one supplied in the cylinder detection phase High voltage pulse be a reduced high voltage pulse i.e. a high voltage pulse, the amplitude of which is for ignition size of typically about 13 kV required in the work cycle cannot reach, but only a size that is typical Is 7 kV and is sufficient for ignition in the exhaust cycle. In this case, it is determined whether a spark has occurred at all and the result for cylinder detection is evaluated.

Once the initial order of the cylinders has been determined, so all further ignition times can be made up to the next one The motor stops incrementally by detecting the crank position fix with the crank sensor. In other words, must cylinder detection is only carried out during the engine start-up phase become. Particularly advantageous on the subject of claim 1 of the present invention is the fact that the usual camshaft sensor can be saved.

According to the preferred development according to claim 3, the predetermined crank position the top dead center of the particular Cylinder. This has the advantage that this Crank position the pressure difference between the work cycle and the exhaust cycle and thus the reliability of the measurement greatest is.

According to the further preferred development according to claim 6 the cylinder detection device has a storage device for storing at least one ignition reference signal and one Comparison device for comparing the ignition detection signal with the ignition reference signal. The ignition reference signal is preferred a reference voltage value that is chosen so that this is less than the voltage amplitude required for ignition, if the relevant cylinder is in the work cycle, but higher than the voltage amplitude required for ignition, when this cylinder is in the exhaust stroke. The ignition reference signal can e.g. B. 9 kV. This training is easy to implement, but requires that to ignite necessary Ignition voltage in the compressed and in the uncompressed state is sufficiently different for reliable cylinder detection to enable.

According to the further preferred development according to claim 7 a plurality of ignition reference signals in the memory device according to different operating states of the internal combustion engine stored, and the comparison device is such designed to be the current operating state of the internal combustion engine corresponding ignition reference signal for comparison attracts. With such a configuration, the fact Be taken into account that the ignition reference signal from the operating state of the engine. Under operating condition are both internal parameters such as Compression pressure as well as external parameters, e.g. Outside temperature or air pressure, to understand.

According to the further preferred development according to claim 8 designed the ignition detection device so that it Ignition voltage of the particular cylinder for two consecutive ones Periods of the ignition alternating voltage are recorded. In this case the cylinder detection device preferably has a storage device for storing the first ignition detection signal and a comparator for comparing the first ignition detection signal with the second ignition detection signal. If the first ignition detection signal represents a higher ignition voltage, is the particular cylinder at the first revolution in Work cycle, otherwise at the second rotation.

According to the further preferred development according to claim 10 is the ignition detection device is designed such that it the ignition voltage of at least two corresponding corresponding Cylinders at the same period of the alternating ignition voltage detected. In this case, the cylinder recognition device preferably a comparison device for comparing the Ignition detection signals corresponding to the two specific cylinders on. The simultaneous application of the ignition voltage to the two specific cylinder and the subsequent comparison of the detection signals has the advantage that the other influencing variables, the influence the ignition voltage, e.g. Electrode gap, gas composition and gas dynamics, usually in both cylinders are the same and therefore compensate each other.

According to claim 1 is the predetermined amplitude, i.e. H. the ignition reference signal, less than the amplitude required for ignition in the work cycle.

Such a reduced amplitude can be achieved, for example, by Reducing the energy supplied to the ignition coil on the primary side, specifically the primary current, or by reducing the slope the switch-off edge of the primary current.

In this case, the predetermined amplitude is preferably the ignition reference signal is higher than that for ignition in the exhaust stroke necessary amplitude.

In such a development, the ignition detection device preferably designed such that it detects whether the certain cylinder has been ignited, i.e. a YES / NO determination performs.

According to the further preferred development is the ignition device for generating bipolar high-voltage pulses designed. In addition to the training courses listed above, preferably in a unipolar ignition device can be realized with such a bipolar Ignition device further advantageous possibilities for cylinder detection.

According to the further preferred development the control device is designed such that it has a control signal to generate a bipolar high voltage pulse with a different first and second predetermined amplitude outputs depending on the respective half-wave. In other words, this training is the positive one and the negative half wave of the ignition voltage is different dimensioned.

In this case, the second predetermined amplitude is preferred the amplitude necessary for ignition in the work cycle, and the first predetermined amplitude less than the second predetermined Amplitude and higher than that necessary for ignition in the exhaust stroke Amplitude. It is also possible in this case that the Control device is designed such that it is the first predetermined Amplitude in successive periods of Ignition alternating voltage of a spark increases until the predetermined one Amplitude higher than that required for ignition in the exhaust stroke Amplitude is.

According to the further preferred development the ignition detection device is designed such that it detects whether the particular cylinder in the first and / or second Half wave has been ignited. Will the particular cylinder already ignited in the first half-wave, it is in the exhaust stroke, otherwise he is in the work cycle.

According to the further preferred development is the ignition detection device on the primary winding the respective ignition coil. Advantageous in this configuration is that it is easily possible to determine the timing of the Detect occurrence of an ignition spark on the primary side and the desired information about the pressure conditions in the win specific cylinder or its current cycle.

According to the further preferred development is a starting signal generating means for generating a Starting signal when starting the engine and output the start signal to the control device for setting the Cylinder detection phase provided. This is an advantage because as already mentioned, the cylinder detection only at the beginning of the Operation of the engine is necessary. For example, the Axilass signal with the starting position of the ignition key.

In the following, the present invention will be more preferred based on Embodiments with reference to the accompanying drawings are explained in more detail.

Fig. 1

eine schematische Darstellung einer bevorzugten Ausführungsform der erfindungsgemäßen Zylindererkennungsvorrichcung,

Fig. 2

eine schematische Darstellung des Zündspannungsverlaufs der Zündwechselspannung bei der Ausführungsform der erfindungsgemäßen Zylindererkennungsvorrichtung gemäß Fig. 1 während einer vollen Periode der Zündwechsel Spannung, in den Zylindern 1 und 4, wobei Zylinder 4 zündet, und

Fig. 3

eine ähnliche Darstellung des Zündspannungsverlaufs wie in Fig. 2, allerdings wird sowohl im Zylinder 1 und 4 ein Zündfunke erzeugt, jedoch zu unterschiedlichen Zeitpunkten, was ausgewertet wird.

The figures show:

Fig. 1

2 shows a schematic representation of a preferred embodiment of the cylinder detection device according to the invention,

Fig. 2

a schematic representation of the ignition voltage curve of the ignition alternating voltage in the embodiment of the cylinder detection device according to the invention according to FIG. 1 during a full period of the ignition alternating voltage, in the cylinders 1 and 4, cylinder 4 igniting, and

Fig. 3

a representation of the ignition voltage curve similar to that in FIG. 2, however an ignition spark is generated in cylinders 1 and 4, but at different times, which is evaluated.

In the figures, identical reference symbols designate the same or functionally identical components.

Fig. 1 shows a schematic representation of a first preferred Embodiment of the cylinder detection device according to the invention.

In Fig. 1, reference numerals 1, 2, 3 and 4 denote a first, second, third and fourth cylinders of a four-cylinder four-stroke engine, which have a respective piston 10, 20, 30, and 40 included, which has a corresponding connecting rod 11, 21, 31 and 41 is connected to a crankshaft 15. The crankshaft 15 is by associated bearings 15a - 15e in the not shown Engine block stored.

There is one in the cylinder head of each cylinder 1, 2, 3 and 4 respective spark plugs 51, 52, 53 and 54 provided which the necessary ignition voltage from a corresponding ignition coil 61, 62, 63 and 64 is supplied.

With the primary side of a respective ignition coil 61, 62, 63 and 64 an associated ignition output stage 71, 72, 73 and 74 is connected, which are used to supply and switch off the primary alternating current Ignition coils 61, 62, 63 and 64 can be controlled.

For this purpose, the ignition output stages 71, 72, 73 and 74 are via respective Control lines 81, 82, 83 and 84, the ignition voltage and / or Set the ignition current with a primary current source, not shown, which is expediently located in a control unit 100 is connected. The primary power source comes with a supply voltage of typically 12 V corresponding to the battery voltage operated.

The control unit 100 also delivers via control lines 91, 92, 93 and 94 control signals to the respective ignition output stages 71, 72, 73 and 74 to determine the duration and thus the beginning and the end to control the primary current supplied to the respective ignition coil. In this context, expressly for the purpose of Disclosure to the previously published EP 0 596 471 A1 by the applicant referenced, in which the control is already detailed of the ignition coils with determining the ignition energy and the ignition duration Signals is disclosed.

The first ignition output stage 71 corresponding to the first cylinder 1 and the ignition output stage 74 corresponding to the fourth cylinder 4 each have a primary-side ignition detection device in Form of a device, not shown, which is used to detect, whether and / or at which ignition voltage the relevant one first and fourth cylinders 1, 4 by a generated high voltage pulse has been ignited and issued a corresponding Ignition detection signal is used. The device can e.g. a primary-side time measuring device or a di / dt measuring device his. The corresponding ignition detection signals are sent to the control unit 100 supplied via signal lines 171 and 174.

A crankshaft sensor 25 is also located on the crankshaft 15 attached with which the crank position and the common upper Dead center of the first and fourth cylinders 1, 4 can be detected can. A corresponding crank signal is sent to control unit 100 supplied via a signal line 125.

Finally, 150 denotes a plurality of further signal lines, which supply corresponding signals to the control device 100, the operating state of the engine, e.g. Temperature, speed, Characterize the position of the ignition key, etc.

The following is the operation of the cylinder detection device thus constructed explained in more detail.

A so-called cylinder detection phase is determined by the starting position of the ignition key defines the control unit 100 communicated one of the signal lines 150. When receiving a Crank signal corresponding to the common crank position OT des first and fourth cylinders 1, 4 via signal line 125 the control unit generates during this cylinder recognition phase 100, a control signal for generating a high voltage AC pulse with an amplitude of z. B. about 9 kV for the first and fourth ignition output stages 71, 74.

The amplitude of 9 kV of the high-voltage pulse is chosen that it is less than the amplitude necessary for ignition, if the first or fourth cylinder 1, 4 in the work cycle is located, but higher than the amplitude required for ignition, when the first and fourth cylinders 1, 4 are in the exhaust stroke is located.

Accordingly, in that of the two cylinders 1, 4, which is in the work cycle (here cylinder 1), none Spark generated, and in the one who is in the exhaust stroke is located (here the cylinder 4), an ignition spark Z is generated.

The primary detection devices provided in the first and fourth ignition output stage 71, 74 detect whether the associated Cylinder 1, 4 have been ignited by the high voltage pulse and deliver a corresponding ignition detection signal via the respective control line 171, 174 to control unit 100.

Based on the waveform of the ignition detection signal thus received the control unit determines with the help of an internal computer, which of the two cylinders 1, 4 is in its working cycle (in shown case of the cylinder 1) and hits a corresponding one Assignment as "cylinder one" for further ignition timing. 2 shows a representation of the ignition voltage curve according to FIG the illustrated embodiment of the cylinder detection device according to the invention of Fig. 1.

2 shows the time on the abscissa while on the ordinate is the secondary voltage on the spark plug 51, 54 of the first and fourth cylinders 1, 4 is shown. It should be noted that the abscissa is divided and always for the first Cylinder 1 and the fourth cylinder 4 the same time Represents process.

The secondary voltage curve of the first cylinder 1 begins with a negative range of approx. -3 kV, which comes from switching on the ignition output stage 71 and not interested here.

When the common crank position OT of the first and fourth cylinders 1, 4 is detected, the primary current of the ignition output stage 71 is switched off with a steep flank, and accordingly a high voltage pulse with an achievable amplitude u of approx. 9 kV, which is caused by u = L di / dt is given. L denotes the mutual inductance of the ignition coil 61 and di / dt the time derivative of the current profile at the time when the primary current is switched off in the relevant ignition output stage. Top dead center of a cylinder is to be understood here.

From relation (1) it can be seen that the size of the achievable Amplitude u of the high voltage pulse on the one hand by reducing the slope of the switch-off edge and on the other hand can be influenced by reducing the switch-off current is.

Since in the present case the achievable amplitude u of the high-voltage pulse not to ignite the one in the work cycle the first cylinder 1 is sufficient, the secondary voltage curve shows a short plateau at 9 kV and falls then off again.

The secondary voltage curve shown on the right in FIG. 2 is different of the fourth cylinder 4. The high voltage pulse also begins here with the negative section of no interest, then only shows an increase up to at OT about 5 kV, where a spark forms prematurely in cylinder 4, because it is in the ejection stroke. The one associated with the spark Ionization causes the voltage to drop to one so-called 3-race plateau at approx. 1 kV, which lasts until turns off the power amplifier. The secondary voltage then occurs the spark plug 64 again.

It should be noted that it is possible instead of the simultaneous detection of the voltage curve in the first and in the fourth cylinder 1, 4 a detection of the voltage curve in both or in only one of these cylinders in two consecutive Revolutions of the crankshaft, because the shown voltage curves in each of the cylinders in this Form of primary-side control occur alternately.

A further embodiment is described below in connection with FIG. 3 of the present invention.

The spark plugs 51, 52, 53 are also in this embodiment and 54, the ignition coils 61, 62, 63 and 64, the ignition output stages 71, 72, 73 and 74 and the control device 100 for generating bipolar High voltage pulses designed. There is a high voltage pulse z. B. from a negative first half-wave and a positive second half-wave, which both in normal operation to generate an ignition spark.

Operation of the cylinder detection device thus constructed runs somewhat.

During the cylinder detection phase, which is analogous to the above lets set the first embodiment, the amplitudes of positive and negative half wave made different sizes.

The first negative half-wave is dimensioned in such a way that they are in the compressed first working cycle Cylinder 1 does not lead to spark formation. The the second positive half-wave, however, receives the amplitude as in normal ignition process. So only the second positive half-wave generate the ignition spark in the first cylinder 1.

Correspondingly, the fourth cylinder 4 is put on when such bipolar high voltage pulse already at the first ignited negative half wave.

The cylinder detection by the cylinder detection devices in the first and fourth ignition output stages 71, 74, that the respective cylinder detection device detects whether the relevant cylinders in the first and / or second half-wave has been ignited.

Claims (23)

1. Apparatus for cylinder recognition in an internal combustion engine, having :

   a crankshaft sensor device (25) for recording a crankshaft angle and a predetermined crankshaft position and for outputting corresponding crankshaft signals;

   an ignition device (51, 52, 53, 54, 61, 62, 63, 64, 71, 72, 73, 74) for firing the respective cylinders 1, 2, 3, 4) of the internal combustion engine by generating corresponding high-voltage pulses in response to corresponding control signals;

   a control device (100) for receiving the crankshaft signals and for outputting the control signals to the ignition device (51, 52, 53, 54, 61, 62, 63, 64, 71, 72, 73, 74) in dependence on at least the crankshaft signals;

   wherein the control device (100) is designed in such a manner that in a cylinder recognition phase upon receiving a crankshaft signal corresponding to a predetermined crankshaft position it outputs a control signal for generating a high-voltage pulse with a predetermined achievable amplitude in at least one specific cylinder (1, 2, 3, 4);
   an ignition recording device to record whether and/or at which ignition voltage the specific cylinder (1, 2, 3, 4) has been fired by the high-voltage pulse and to output a corresponding ignition recording signal; and
   a cylinder recognition device for determining whether the specific cylinder (1, 2, 3, 4) is in the predetermined crankshaft position in its ignition stroke, based on at least the ignition recording signal,
   characterised in that the predetermined amplitude is smaller than the amplitude required for ignition in the ignition stroke.
2. Cylinder recognition apparatus according to one of the preceding Claims,
   characterised in that the ignition recording device is provided at the primary-side winding of the respective ignition coil (61, 62, 63, 64).
3. Cylinder recognition apparatus according to Claim 1 or 2,
   characterised in that the predetermined crankshaft position is at least approximately the top dead centre of the specific cylinder (1, 2 , 3, 4).
4. Cylinder recognition apparatus according to one of Claims 1 to 3,
   characterised in that the ignition recording device is designed in such a manner that it records the ignition voltage of the specific cylinder (1, 2, 3, 4).
5. Cylinder recognition apparatus according to Claim 4,
   characterised in that the cylinder recognition device comprises a memory device for storing at least one ignition reference signal and a comparison device for comparing the ignition recording signal with the ignition reference signal.
6. Cylinder recognition apparatus according to Claim 4,
   characterised in that in the memory device are stored a plurality of ignition reference signals corresponding to different operating states of the internal combustion engine and the comparison device is designed in such a manner that it makes use of an ignition reference signal corresponding to the current operating state of the internal combustion engine for comparison.
7. Cylinder recognition apparatus according to one of Claims 1 to 3,
   characterised in that the ignition recording device is designed in such a manner that it records the ignition voltage of the specific cylinder (1, 2, 3, 4) during two successive periods.
8. Cylinder recognition apparatus according to Claim 7,
   characterised in that the cylinder recognition device comprises a memory device for storing the first ignition recording signal and a comparison device for comparing the first ignition recording signal with the second ignition recording signal.
9. Cylinder recognition apparatus according to one of Claims 1 to 3,
   characterised in that the ignition recording device is designed in such a manner that it records the ignition voltage of at least two specific cylinders (1, 4) that correspond to one another during the same rotation of the crankshaft (15).
10. Cylinder recognition apparatus according to Claim 9,
    characterised in that the cylinder recognition device comprises a comparison device for comparing the ignition recording signals corresponding to the two specific cylinders (1, 4).
11. Cylinder recognition apparatus according to one of Claims 1-3,
    characterised in that the predetermined amplitude is higher than the amplitude required for ignition in the exhaust stroke.
12. Cylinder recognition apparatus according to one of Claims 1 - 3,
    characterised in that the control device (100) is designed in such a manner that it increases the predetermined amplitude during successive periods of the crankshaft (15) until the predetermined amplitude is higher than the amplitude required for ignition in the exhaust stroke.
13. Cylinder recognition apparatus according to Claim 12 or 11,
    characterised in that the ignition recording device is designed in such a manner that it records whether the specific cylinder (1, 2, 3, 4) has been fired.
14. Cylinder recognition apparatus according to Claim 12 or 11,
    characterised in that the ignition recording device is designed in such a manner that during two successive periods of the crankshaft it is recorded whether the specific cylinder (1, 2, 3, 4) has been fired.
15. Cylinder recognition apparatus according to Claim 12 or 11,
    characterised in that the cylinder recording device is designed in such a manner that it records whether one of at least two specific cylinders (1, 4) corresponding to each other has been fired.
16. Cylinder recognition apparatus according to one of the preceding Claims,
    characterised in that the ignition device (51, 52, 53, 54, 61, 62, 63, 64, 71, 72, 73, 74) is designed to generate bipolar high-voltage pulses.
17. Cylinder recognition apparatus according to Claim 16,
    characterised in that the control device (100) is designed in such a manner that it outputs a control signal for the generation of a bipolar high-voltage pulse with a different first and second predetermined amplitude in dependence on the respective half wave.
18. Cylinder recognition apparatus according to Claim 17,
    characterised in that the second predetermined amplitude is the amplitude required for ignition in the ignition stroke and the first predetermined amplitude is less than the second predetermined amplitude.
19. Cylinder recognition apparatus according to Claim 18,
    characterised in that the first predetermined amplitude is higher than the amplitude required for ignition in the exhaust stroke.
20. Cylinder recognition apparatus according to Claim 18,
    characterised in that the control device (100) is designed in such a manner that it increases the first predetermined amplitude during successive rotations of the crankshaft (15) until the predetermined amplitude is higher than the amplitude required for the ignition (Z) in the exhaust stroke.
21. Cylinder recognition apparatus according to Claim 20 or 19,
    characterised in that the ignition recording device is designed in such a manner that it records whether the specific cylinder (1, 2, 3, 4) has been fired in the first and/or second half wave.
22. Cylinder recognition apparatus according to one of the preceding Claims,
    characterised in that a starting signal generating device for generating a starting signal is provided when starting the internal combustion engine and outputting the starting signal to the control device to establish the cylinder recognition phase.
23. A cylinder recognition method in an internal combustion engine having the following steps:

    recording a crankshaft angle and a predetermined crankshaft position and outputting corresponding crankshaft signals;

    generating a high-voltage pulse having a predetermined achievable amplitude in at least one specific cylinder (1, 2, 3, 4) when recording a predetermined crankshaft position during a cylinder recognition phase;

    recording whether and/or at which ignition voltage the specific cylinder (1, 2, 3, 4) has been fired by the high-voltage pulse and outputting a corresponding ignition recording signal; and

    determining whether the specific cylinder (1, 2, 3, 4) is in the predetermined crankshaft position in its ignition stroke, based on at least the ignition recording signal,

    characterised in that the predetermined amplitude is smaller than the amplitude required for ignition in the ignition stroke.

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