Method for correcting an angular position measurement in an internal combustion engine

Abstract

A method for determining the angular position of an engine comprising the following steps: - detection of a first operating mode of the engine; - measurement of a first time interval between the passage of a tooth front before the combustion tooth front, called the anterior tooth front, and the passage of the combustion tooth front; - measurement of a second time interval between the passage of the combustion tooth front and the passage of a tooth front after the combustion tooth front, called the posterior tooth front; - comparison of the first time interval with the second time interval; and - determination of a correction term for the angular position measurement obtained from the sensor based on the result of the comparison of the first time interval with the second time interval. Abstract figure: Figure 1

Description

Title of the invention: Method for correcting an angular position measurement in an internal combustion engine

[0001] This disclosure relates to a method for correcting an angular position measurement in an internal combustion engine. technical field

[0002] The technical field of the present invention is thus the field of engine control for an internal combustion engine. This disclosure is intended in particular for a motor vehicle or similar (motorcycle, truck, etc.) but can also be used for other engine applications (lawnmower or other mobile motorized tool, stationary engine, etc.). Previous technique

[0003] In an internal combustion engine, at least one piston slides back and forth within a cylinder, thus defining a combustion chamber of variable volume. A connecting rod transforms this linear motion into a rotary motion. The position of each piston within its cylinder is determined by the angular position of a flywheel. This angular position is determined in a manner known to those skilled in the art, and not detailed here, using a position sensor associated with teeth on the periphery of the flywheel. Knowing the position of each piston within its cylinder allows the engine's operation to be managed, and in particular, to determine when (or at what angular position of the flywheel) fuel should be injected into a cylinder.

[0004] The use of the position sensor makes it possible to determine the angular position of a motor each time a tooth of the gear passes in front of the position sensor (upward or downward, or both). However, the position indicated by the sensor has an accuracy of only a few degrees (for example, 2 to 3°). This is due to manufacturing tolerances, particularly in the gear teeth and the positioning of the position sensor relative to these teeth.

[0005] This level of precision is sufficient for proper engine management in accordance with current legislation. However, to achieve finer engine management, particularly of fuel injection and possibly ignition control of the injected fuel, it is desirable to obtain a precision lower than 1° if possible. The technical problem of better determining the position of the pistons in an engine can concern spark-ignition engines, compression-ignition engines, and more specifically, but not exclusively, so-called four-stroke engines. Summary

[0006] The present disclosure improves the situation. Its purpose is, in particular, to provide a solution for determining the angular position of a motor more accurately using the sensors typically found in a motor, thereby overcoming the mounting tolerances of said sensors and the machining of a target with associated teeth. Preferably, this method will allow for greater accuracy without having to modify the target and / or the sensor used to perform the position measurement. Furthermore, advantageously, this method will not require the use of new components in a motor to be implemented.

[0007] A method for determining the angular position of an internal combustion engine is proposed in which an angular position measurement is carried out using a target having teeth regularly distributed around its periphery with a singularity and associated with a sensor detecting the passage of a tooth front for each tooth, a passage in front of a tooth front theoretically corresponding to the passage in the engine of a predetermined piston at a top dead center at the end of compression in a corresponding cylinder, said tooth front being referred to hereafter as the combustion tooth front.

[0008] According to this disclosure, this process is expected to include the following steps: - detection of a first predetermined operating mode of the motor; - measurement of the first time elapsed between the passage of a tooth front passing in front of the sensor before the combustion tooth front, called the anterior tooth front, and the passage of the combustion tooth front; - measurement of a second time elapsed between the passage of the combustion tooth front and the passage of a tooth front passing in front of the sensor after the combustion tooth front, called the posterior tooth front, the posterior tooth front being symmetrical to the anterior tooth front with respect to the combustion tooth front; - comparison of the first time with the second time, these two times being theoretically equal if the combustion tooth front passes in front of the sensor when the predetermined piston passes through its top dead center at the end of compression; and - determination of a first correction term of the angular position measurement measured by the sensor from the result of the comparison of the first time with the second time according to a predetermined formula corresponding to a type of motors.

[0009] This method makes it possible to determine whether the actual top dead center is correctly centered with respect to the measurements taken. This method first allows for the detection of any misalignment between the sensor and the target.

[0010] The features described in the following paragraphs may optionally be implemented independently of each other or in combination. combinations with each other:

[0011] - the first predetermined operating mode of the motor corresponds to a function engine idling;

[0012] - the anterior tooth front corresponds to the tooth front immediately preceding the combustion tooth front and the posterior tooth front corresponds to the tooth front immediately following the combustion tooth front;

[0013] According to a first variant of this method for determining the angular position of an internal combustion engine, the comparison between the first time and the second time corresponds to a difference; the value of the difference is filtered to give a filtered difference, and the first correction term corresponds to an affine function of the filtered difference.

[0014] This first variant relates more particularly to an engine with irregular ignition, and the process according to this first variant may further include the following steps: - measurement of a third time elapsed between the passage of the tooth front passing in front of the sensor one revolution, i.e. 360°, after the anterior tooth front, and the passage of the tooth front one revolution after the combustion tooth front; - measurement of a fourth time elapsed between the passage of the tooth front one revolution after the combustion tooth front and the passage of the tooth front passing in front of the sensor one revolution after the posterior tooth front; - determination of a second correction term of the angular position measurement measured by the sensor from the result of the comparison of the third time with the fourth time according to a predetermined formula corresponding to a type of motors.

[0015] An irregular ignition engine is defined herein as any engine in which a position at 360°CRK after a top dead center of combustion does not correspond to combustion in a cylinder of said engine. An irregular ignition engine is thus, for example, a single-cylinder four-stroke engine or a three- or five-cylinder engine with evenly distributed ignition over 720° (four-stroke engine). Two-stroke engines are excluded here.

[0016] In this first variant, it can also be provided that the comparison between the third time and the fourth time corresponds to a difference, that the value of the difference is filtered to give a filtered difference, and that the second corrective term corresponds to an affine function of the filtered difference.

[0017] According to a second variant of the method for determining the angular position of an internal combustion engine. This variant is intended for any type of internal combustion engine, two-stroke or four-stroke, irregular or not.

[0018] According to this second variant, it is proposed that the comparison of the first time with the second time is a calculation of a first ratio corresponding to the ratio between the second time and the first time; and that the process also includes the following steps: - detection of a second predetermined operating mode of the motor; - measurement of a third time elapsed between the passage of a tooth front passing in front of the sensor before the combustion tooth front, called the anterior tooth front, and the passage of the combustion tooth front; - measurement of a fourth time elapsed between the passage of the combustion tooth front and the passage of a tooth front passing in front of the sensor after the combustion tooth front, called the posterior tooth front, the posterior tooth front being symmetrical to the anterior tooth front with respect to the combustion tooth front; - comparison of the third beat with the fourth beat by calculating a second ratio corresponding to the ratio between the fourth beat and the third beat; and - determination of the first correction term of the angular position measurement measured by the sensor from the ratio between the first ratio and the second ratio according to a predetermined formula corresponding to a type of motors.

[0019] In this second variant, it can also be foreseen that the second predetermined operating mode of the motor corresponds to operation at a high speed, i.e. above a predetermined speed, and at a low load, i.e. at a load lower than a predetermined load.

[0020] According to another aspect, a computer program is proposed comprising instructions for the implementation of a process presented above when this program is executed by a processor, in particular an electronic control unit of an internal combustion engine.

[0021] According to another aspect, a non-transient, computer-readable recording medium is proposed on which such a program is recorded. Brief description of the drawings

[0022] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which: Fig. 1

[0023] [Fig.1] shows variations in the torque of a motor over time. Fig. 2

[0024] [Fig.2] shows a flowchart for implementing a method according to the present disclosure. Description of the implementation methods

[0025] The present disclosure relates to a configuration known to those skilled in the art, according to which the angular position of an internal combustion engine is achieved at Starting with a toothed target and a corresponding position sensor, we assume that this engine operates on a four-stroke cycle, meaning that a piston makes two up-and-down strokes in a cylinder to complete a combustion cycle (intake, compression, power, and exhaust). This piston is connected to a crankshaft by a connecting rod. The flywheel is fixed to the crankshaft and therefore makes two revolutions, or a 720° rotation, for one combustion cycle. This flywheel has teeth around its periphery, thus forming the aforementioned target. Each tooth corresponds to an adjacent groove. The periphery of the flywheel is then divided into N evenly spaced sectors, each sector comprising one tooth and an adjacent groove. However, to create a reference R on the flywheel, at least one tooth is removed.Thus, there are (Ni) teeth on the periphery of the flywheel with an angular offset of (360 / N)° between two successive teeth, except of course at the reference point R. The sensor associated with the flywheel detects the passage of each tooth. This is, for example (non-exhaustive list), a variable reluctance sensor or a Hall effect sensor. However, as is known, only a tooth edge is detected. We assume, for example, that the sensor detects falling edges, that is, the passage of a tooth past the sensor into a gap during the rotation of the flywheel. Thus, in the following description, when a tooth edge is referred to, it refers to a tooth edge detected by the sensor, i.e., in the assumption made here, a falling tooth edge.

[0026] It is further assumed here that the engine considered as a purely illustrative and non-limiting example is a two-cylinder V engine at 90°. In this case, each of the two pistons passes through its top dead center (TDC) once during a combustion cycle. Here, only the top dead center after a compression stroke is considered to be that point, i.e., the top dead center near which fuel is injected. Numbering the two cylinders 0 and 1, we then have two top dead centers: TDC0 and TDC1. It is assumed here that the flywheel is mounted on the crankshaft such that each top dead center, TDC1, coincides with the falling flank of a tooth. In this case (two-cylinder V engine at 90°), the top dead centers are not evenly distributed over a 720°CRK engine cycle.Between a top dead center (TDC) PMHO and the next TDC PMHI, there is a difference of 270°CRK and between a TDCHI and the next TDC PMHO, there is 450°CRK ([Fig. 1]).

[0027] Despite all the care taken in machining the target and positioning the sensor relative to the target, manufacturing tolerances inevitably exist, resulting in a discrepancy between the actual engine position (in °CRK) and the position measured by the sensor. For example, during a top dead center passage, the tooth front, which is theoretically facing the sensor and is theoretically detected during this top dead center passage, is slightly offset relative to the sensor. The measurement accuracy is most often on the order of 2 or 3°CRK.

[0028] This measurement error affects engine performance. For example, in a spark-ignition engine, the ignition timing is offset from the theoretical position. As a result, combustion is not optimal and fuel consumption is impacted.

[0029] A method is proposed below for knowing the position of the motor with greater precision, not by modifying the target and / or the sensor, but by taking into account the geometric tolerances in the motor.

[0030] Figure 1 shows a first curve corresponding to the instantaneous torque exerted on the crankshaft of the engine considered as a function of time. By integrating this curve, we obtain a quantity representative of an overall torque, or average gas torque, exerted on the crankshaft.

[0031] It is proposed here to measure a convolution product of a function f varying with the angular position of the engine and the instantaneous torque exerted by the pistons on the crankshaft. Reference is made here to document FR3084114A1 (in particular pages 5 to 8) for the theoretical calculations corresponding to the convolution product.

[0032] The function f chosen here is also shown in [Fig. 1]. It is a function with a triangular profile centered on a top dead center, preferably here top dead center TDC1. This function has a value of 0 except over an interval around TDC1. Since top dead center corresponds to the passage of a tooth front, this interval begins one or two tooth fronts before the considered top dead center and ends respectively one or two tooth fronts after this top dead center. For example, if the teeth of the target are spaced 15° apart (N=24 higher), f will have a value of 0 up to TDC1-15°CRK and from TDC1+15°CRK onwards, and between these two values, will have a triangular profile (isosceles triangle, therefore symmetrical with respect to TDC1).

[0033] If the result of the convolution product is zero, that is, if the average gas torque over the interval is zero, then the triangle corresponding to the function f is indeed centered on TDC1 and therefore the value measured by the sensor corresponds to the theoretical value. No correction is therefore necessary a priori. As a first approximation, the value given by the sensor is correct.

[0034] If the result of the convolution product is positive, then the average torque over the interval is positive, and therefore the triangle corresponding to the function f is shifted (to the right in [Fig. 1]) relative to the actual dead center. The measured value is too large, and a negative correction must be applied to the values ​​measured by the sensor as a first approximation. Conversely, if the result of the convolution product is negative, the triangle is shifted to the left in [Fig. 1], and a positive correction must be applied to the measured values ​​as a first approximation.

[0035] As can be seen from the description in document FR3084114A1, particularly pages 5 and 6, the convolution product mentioned above, i.e. the average gas couple T over the interval considered, is written in the form: T = k * RPMA3 * (dO-dl) with : k: constant RPM: engine rotation speed RPMA3: engine rotation speed cubed dO: duration of passage of the tooth preceding the top dead center considered dl: duration of passage of the tooth following the top dead center considered.

[0036] The times d0 and dl correspond to the times elapsed between two consecutive signals emitted by the position sensor. These times correspond to the passage time between two successive descending tooth fronts. A passage time of two or more teeth could be used, but for an angular difference of 15° between two teeth, the passage of a single tooth is sufficient. Here, d0 and dl must correspond to the same crankshaft rotation.

[0037] This initial measurement already allows for a correction to be applied to the measured value of the angular position. However, this correction does not take into account any geometric defects in the target itself. Indeed, if the angular difference between two successive tooth fronts is not identical, the corrective measurement proposed above cannot account for it. To then also consider the geometry of the target, it is proposed to repeat the measurement, using the same tooth fronts but without the influence of combustion.

[0038] Figure 1 illustrates a second triangle, similar to the first, but offset by 360°CRK. Here, the second measurement is not (or only slightly) influenced by combustion. A convolution product is performed, and it is proposed to subtract the result obtained by this second convolution product from the result obtained with the first convolution product. This difference corresponds to a torque that reflects a shift between the theoretical and actual positions of the top dead center (TDC) under study (here TDC1), but which is no longer influenced by the geometry of the target.

[0039] Here, d(nl) denotes the passage time of the tooth preceding the tooth corresponding to the considered top dead center (TDC) on the revolution following the passage of this TDC, and dn denotes the passage time of the tooth following the tooth corresponding to the considered TDC on the revolution following the passage of this TDC. The passage time here corresponds to the time between the emission of two signals by the position sensor at the passages of the tooth fronts under consideration. The passage time of a tooth therefore corresponds to the time between the emission of two successive signals. The triangular profile used here is the same as that used at the considered TDC.

[0040] As indicated, the difference of the two convolution products corresponds to a pair, hereinafter referred to as the corrected pair TC given by the formula: TC = k * RPMA3 * (dO-dl+dn-d(nl))

[0041] It has been assumed here that the times di corresponded to the passage of one tooth, i.e. an angle of 15°CRK (within the manufacturing tolerance of the target) but one could consider another number of teeth and / or another angle of rotation.

[0042] There are preferred conditions for carrying out the measurement of the correction to be applied to the angular position result provided by the motor position sensor.

[0043] It is noted that tooth passage times are measured. As a result, greater accuracy is obtained when the engine speed is low.

[0044] To avoid distorting the measurement, it is best to prevent "parasitic" torques from acting on the crankshaft. Therefore, it is advisable to take a measurement when the load applied to the engine is low. A measurement taken at idle is preferable, ideally when the engine is disengaged from its associated transmission components.

[0045] The moving parts of the engine also exert an action (torque) on the crankshaft. The piston and connecting rod corresponding to the cylinder in question have a negligible influence on combustion, and also, during the passage through top dead center of the exhaust stroke (or crossover), the angle of deflection, and therefore the lever arm, is small, and the torque is thus also small. The other moving masses, in particular the other piston(s) and connecting rod(s), have constant masses and an influence that, on the one hand, does not vary and, on the other hand, is controllable.

[0046] In conclusion, the correction measure is preferably made at idle, ideally with the engine disengaged from its transmission.

[0047] Figure [Fig. 2] summarizes the determination process that has just been described.

[0048] A first step 100 consists of determining whether the engine is in good condition to carry out the measurement, that is to say this step consists of checking that the engine is idling.

[0049] If the engine is idling (case 1), the process proceeds to a step 200 described below and otherwise (case 0), the process proceeds to a step 600 described later.

[0050] Step 200 consists of measuring the tooth passage times. For example, we can consider the non-limiting embodiment in which, theoretically, a tooth front (a descending one, for example) corresponds to the passage of a piston through its top dead center of combustion. We then measure d0, which corresponds to the time elapsed between the passage of the previous (descending) tooth front and the passage of the tooth front corresponding to the considered top dead center of combustion. Here, we could use a longer interval which, instead of corresponding to the passage of one tooth, would correspond to the passage of two or three teeth (theoretically, possibly more). In this case, each time, we must measure a time corresponding to the same number of teeth.

[0051] During step 200, the time dl is also measured, which corresponds to the time elapsed between the passage of the tooth front corresponding to the top dead center of combustion and the passage of the next tooth front. Then, the same values ​​are measured but with a 360° offset, that is, the passage of the same teeth one revolution further, corresponding to the passage of the piston in the cylinder considered at the exhaust top dead center, also called the overlap top dead center. Thus, dm (corresponding to d(nl) above) and dn are measured.

[0052] Once all these values ​​have been acquired, step 300 provides for the calculation of a duration Dur according to the formula: Dur = dO-dl+dn-dm.

[0053] Several measurements are taken for Dur and the values ​​obtained are filtered during a step 400 to obtain a filtered value Dur_filt.

[0054] A correction value Crk_dev to be applied to the position measurements taken by the position sensor detecting the passage of the tooth fronts (descending) is obtained (step 500) by an affine function with Dur_filt as a variable, i.e. that we have: Crk_dev = a * Dur_filt + b where a and b are constants that depend on the type of motor and can therefore be calibrated once and for all on a test motor.

[0055] The correction value Crk_dev is then subsequently applied to any position measurement made by the position sensor (step 600).

[0056] Optionally, a step 700 may be provided in the present process for displaying an alert when the value of Crk_dev falls outside a predefined range.

[0057] This process is particularly suited to four-stroke engines with an odd number of cylinders, or to engines with an even number of cylinders where combustion is not evenly distributed over 720°CRK (such as, for example, a V-twin engine). For other cases, that is, for engines where each time there is combustion in one cylinder there is another combustion in another cylinder one revolution (i.e., 360°CRK) later, a slightly different strategy is proposed.

[0058] A measurement of dO and dl as above is first proposed. It is then proposed to repeat the measurements of dO and dl but at high speed, that is to say beyond a predefined speed, preferably at low load, for example during deceleration.

[0059] Here we come to compare dO to dl each time. However, here instead of finding the difference between the two time measurements, it is proposed to find the ratio of dO to dl.

[0060] Ratio_IS is then called the dO / dl ratio when the engine is idling, for example under the conditions defined in step 100 (low speed, i.e., below (at a predetermined regime and low load).

[0061] Ratio_HighRPM is called the ratio dO / dl of the times dO and dl measured at high engine speed and preferably at low load.

[0062] Of course, the values ​​of Ratio_IS and Ratio_HighRPM are preferably filtered and the filtered values ​​of these ratios are subsequently used.

[0063] Logically, if the considered top dead center of combustion coincides with the passage of the corresponding tooth front, the difference between dO and dl varies due to the difference in rotational speed, but the ratio dO / dl is insensitive to the engine's rotational speed. Thus, if: Ratio_IS = Ratio_HighRPM or Ratio_IS / Ratio_HighRPM = 1 (which is equivalent) there is no compensation to be made to the engine position measurement.

[0064] Conversely, if the opposite is true, compensation will be required. If the Ratio_IS / Ratio_HighRPM > 1, then positive compensation is planned, while if Ratio_IS / Ratio_HighRPM < 1, negative compensation is planned.

[0065] Here too, depending on the Ratio_IS / Ratio_HighRPM ratio and the type of engine, a pre-established table allows us to know the compensation to be provided.

[0066] In summary, it is possible to determine the angular position of an internal combustion engine by conventionally measuring its position, i.e., with a target and an associated sensor, and then compensating for the measured value. Originally, this compensation is determined using measurements taken by the position sensor, without the use of any other sensor or component. The position sensor detects the passage of tooth fronts over the target. As is known, the time between two successive passages of a tooth front is measured to determine the engine's rotational speed, this speed being an important parameter for engine regulation.

[0067] Typically, engines are designed so that the top dead center (TDC) position of a cylinder corresponds as closely as possible to the passage of a tooth front relative to the position sensor, as this TDC position is a reference position, particularly for combustion. Here, we are interested in the passage time of the tooth (or two or three teeth) preceding the passage of a predetermined combustion TDC to be considered, and the passage time of the tooth (or two or three teeth). The same number of teeth are considered before and after the combustion TDC.

[0068] The passage time measurements are taken under predetermined conditions, preferably when the motor is not under load so that its rotation is not disrupted by external loads that exert a resisting torque on the engine's crankshaft. Without external loads, the measurements are not influenced by parasitic torques that cannot be taken into account because they are unknown.

[0069] Top dead center (TDC) is a special measurement point because significant torque variations occur when the engine is in this angular position. It is therefore an interesting point for measurements. By comparing the time it takes for a tooth (or n teeth) to reach this TDC with the time it takes for a tooth (or n teeth) to pass this TDC, it is possible to determine whether the TDC is centered with respect to the measurements taken, and therefore whether the actual TDC is offset from the theoretical TDC, which corresponds to a measurement point. Depending on the observed time difference, a correction may or may not be necessary as a first approximation.

[0070] This initial difference in transit time allows for the consideration of sensor positioning errors relative to the target, but does not allow for the detection of any error related to the target itself. To account for such errors, optionally and preferably, another measurement is performed using the same teeth, under different torque conditions, and the results of the second measurement are subtracted (or vice versa) from those of the first measurement to eliminate the influence of geometric errors on the measurements. Industrial application

[0071] The present technical solutions can be applied in particular in motor control to improve the accuracy of this control.

[0072] The proposed method, and the corresponding means for implementing this method, allow for a more precise determination of the engine's actual angular position. It is then possible to reduce the margins for adjusting the ignition timing (on a spark-ignition engine) and thus optimize fuel consumption.

[0073] The proposed solution allows for a relaxation of the mechanical adjustment constraints during the positioning of the target relative to the sensor, since positioning errors are corrected. As a result, the mechanical assembly is simplified, thereby reducing assembly time and manufacturing costs.

[0074] For engine control, it is now possible to compensate for measurements taken, such as engine pressure readings, ignition timing control (better torque matching), injection timing control (for direct injection engines, including diesel types), ...

[0075] Optionally, it is also possible to warn a user (or after-sales service) if discrepancies are detected outside a predetermined range.

[0076] The proposed calculations are very simple to perform at the level of an electronic unit and already give very good results even when the time measurements are not made with high precision. The field of application of the method proposed in this disclosure extends, in addition to automotive and two- or three-wheeled vehicle applications, also to non-automotive applications and in particular to small engines such as, for example, four-stroke single-cylinder engines, irregular V-twin engines, three-cylinder engines, irregular four-cylinder engines, etc. However, as mentioned, an alternative embodiment is suitable for all engines, whether two-stroke or four-stroke.

[0077] This disclosure is not limited to the proposed embodiment examples and variants described above, which are only examples, but encompasses all variants that a person skilled in the art may consider within the framework of the protection sought.

Claims

Demands

1. A method for determining the angular position of an internal combustion engine in which an angular position measurement is carried out using a target having teeth regularly distributed around its periphery with a singularity and associated with a sensor detecting the passage of a tooth front for each tooth, a passage in front of a tooth front theoretically corresponding to the passage in the engine of a predetermined piston at a top dead center at the end of compression in a corresponding cylinder, said tooth front being hereinafter referred to as the combustion tooth front, the method being characterized in that it comprises the following steps: - detection of a first predetermined operating mode of the engine (100); - measurement of a first time elapsed between the passage of a tooth front passing in front of the sensor before the combustion tooth front, called the anterior tooth front, and the passage of the combustion tooth front (200); - measurement of a second time elapsed between the passage of the combustion tooth front and the passage of a tooth front passing in front of the sensor after the combustion tooth front, called the posterior tooth front, the posterior tooth front being symmetrical to the anterior tooth front with respect to the combustion tooth front (200); - comparison of the first time with the second time, these two times being theoretically equal if the combustion tooth front passes in front of the sensor when the predetermined piston passes through its top dead center at the end of compression (300); the comparison between the first time and the second time corresponds to a difference (300), and the value of the difference is filtered to give a filtered difference (400), and - determination of a first correction term of the angular position measurement measured by the sensor from the result of the comparison of the first time with the second time according to a predetermined formula corresponding to a type of motor (500), the first correction term corresponds to an affine function of the filtered difference, - determination of the angular position of the motor, by applying the first correction term determined to the measurement of the angular position measured by the sensor.

2. A method according to claim 1, characterized in that the first mode The predetermined operating mode of the engine corresponds to an idle engine operation.

3. A method according to any one of claims 1 or 2, characterized in that the anterior tooth front corresponds to the tooth front immediately preceding the combustion tooth front and the posterior tooth front corresponds to the tooth front immediately following the combustion tooth front.

4. A method for determining the angular position of an internal combustion engine according to any one of claims 1 to 3, characterized in that the engine is an irregular ignition engine, and in that the method further comprises the following steps: - measuring a third time elapsed between the passage of the tooth front passing in front of the sensor one revolution, i.e. 360°, after the front tooth front, and the passage of the tooth front one revolution after the combustion tooth front (200); - measuring a fourth time elapsed between the passage of the tooth front one revolution after the combustion tooth front and the passage of the tooth front passing in front of the sensor one revolution after the rear tooth front (200);- determination of a second correction term of the angular position measurement measured by the sensor from the result of the comparison of the third time with the fourth time according to a predetermined formula corresponding to a type of motor (500).;

5. A method according to claim 4, characterized in that the comparison between the third time and the fourth time corresponds to a difference, in that the value of the difference is filtered to give a filtered difference, and in that the second correction term corresponds to an affine function of the filtered difference.

6. A method for determining the angular position of an internal combustion engine according to any one of claims 1 to 3, characterized in that comparing the first time step with the second time step is a calculation of a first ratio corresponding to the ratio between the second time step and the first time step; and in that the method further comprises the following steps: - detection of a second predetermined operating mode of the engine; - measurement of a third time step elapsed between the passage of a tooth front passing in front of the sensor before the combustion tooth front, called anterior tooth front, and the passage of the combustion tooth front; - measurement of a fourth time elapsed between the passage of the combustion tooth front and the passage of a tooth front passing in front of the sensor after the combustion tooth front, called the posterior tooth front, the posterior tooth front being symmetrical to the anterior tooth front with respect to the combustion tooth front; - comparison of the third time with the fourth time by calculating a second ratio corresponding to the ratio between the fourth time and the third time; and - determination of the first correction term of the angular position measurement measured by the sensor from the ratio between the first ratio and the second ratio according to a predetermined formula corresponding to a type of engine.

7. The method according to claim 6, characterized in that the second predetermined operating mode of the motor corresponds to operation at a high speed, i.e. above a predetermined speed, and at a low load, i.e. at a load lower than a predetermined load.

8. Computer program comprising instructions for carrying out a method according to any one of claims 1 to 7 when this program is executed by a processor, in particular an electronic control unit of an internal combustion engine.

9. Non-transient computer-readable recording medium on which is recorded a program for the implementation of a method according to any one of claims 1 to 7 when this program is executed by a processor, in particular an electronic control unit of an internal combustion engine.

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