• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention proposes a method for adapting a detection threshold (S1) of a magnetic field sensor for a motor vehicle crankshaft equipped with the "Stop and Restart" function, said sensor delivering a signal (B). magnetic field variations having two states such as: • State 1: when the crankshaft is rotating: the signal includes rising edges and falling edges, • State 2: when the crankshaft is at a standstill: the present signal an aperiodic progressive drift (ΔTAR), according to the invention the method comprises, for the state 2, stages making it possible to estimate the variation (Δ1, Δ2, Δ3, Δ4 ... Δi) of value (V1, V2 ... Vi) of the signal (B) during the stopping phase of the crankshaft in order to adapt the detection threshold (S1) to a new value (S4) applicable for the detection of the first tooth at engine restart (R).
    公开号:FR3021739A1
    申请号:FR1455013
    申请日:2014-06-03
    公开日:2015-12-04
    发明作者:David Mirassou；Marie-Nathalie Larue
    申请人:Continental Automotive GmbH；Continental Automotive France SAS；
    IPC主号:
    专利说明:

    [0001] The present invention relates to a method of adapting a detection threshold of a crankshaft sensor for a motor vehicle. More particularly, it is a question of improving the accuracy of the electrical signal delivered by a sensor mounted in front of a toothed wheel situated at the end of a crankshaft of an engine of a motor vehicle.
    [0002] The crankshaft sensors are used in a motor vehicle to determine the position of the crankshaft, the speed of rotation and the direction of rotation of the engine. Used in combination with camshaft sensors, they determine the position of the different cylinders in the combustion cycle of the engine (ie determine for each cylinder if it is in phase of admission, in phase compression, in the explosion phase or in the exhaust phase) and make it possible to better manage the operation of the engine, by optimally adjusting the ignition advance or the fuel injection time. These crankshaft sensors comprise a magnetic field generator (example: a permanent magnet), a magnetic field detection means (Hall effect cell, magneto-resistive cell MR, giant magnetoresistive cell GMR, ... for example) and a electronic circuit for processing the signal received by the magnetic field detection means. These sensors, called active sensors, deliver a digital signal to a central computer for processing. The magnetic field generator may also be a target, composed of a magnetic material, having alternating South and North poles. In this case, the sensor incorporates or no permanent magnet according to the detection means used. Subsequently, we will assimilate the South and North poles to the teeth and troughs of a mechanical target. In known manner and as illustrated in Figure 1, a crankshaft sensor 10 is associated with a target 14 secured to a crankshaft 16. This target 14 is in the form of a disk 15 whose periphery is toothed. Between each tooth T1, 12, T3 substantially identical, is a spacing (hollow) C1, C2, C3. The target is distinguished by the presence of a hollow Ce longer, more commonly called "missing tooth" (or "missing tooth" in English) positioned precisely at a certain angle relative to the angular position of the engine. According to the embodiment described and shown in FIG. 1, a crankshaft sensor 10 comprises, in a known manner, a ferromagnetic element 11 and a magnetic field detection means 12 (for example a Hall effect cell). This sensor 10 delivers a digital signal to one of the processing means 13.
    [0003] The operation of such a sensor assembly 10 and the associated target 14 is described below. When the target 14 is rotated (arrow F in FIG. 1) by the crankshaft 16, the sensor 10 perceives a series of variations of the magnetic field 5 representative of the tooth or teeth T1, T2, T3 passing in front of it and their spacing C1 , C2, 03, Ce. The signal thus obtained is represented in FIG. 2. In FIG. 2, the signal B of the magnetic field delivered by the sensor 10 as a function of the angle of rotation 0 of the crankshaft 16, as well as the threshold S1 for detecting the rising edge and the falling edge of the first tooth T. FIG. 3 represents the position of the teeth T1, 12, ... T, and recesses C1, 02 ... C, of the target 14 relative to the signal B of the magnetic field of FIG. 2. As illustrated in FIG. 2, to determine the position of the crankshaft, the signal B represents the variations of the magnetic field perceived by the crankshaft sensor 16 during a rotation of the target 14, that is to say at a rotation angle θ of the target 14. This signal has a sequence of sinusoids D1, D2 ... Di each corresponding to the variation of the magnetic field measured by the sensor 10 when a tooth T1, T2 ... T, (see Figure 3) followed by a hollow C1, 02 ... C, passes in front of said sensor 10. By counting the number of sinusoids D1, D2 ... D ,, by measuring the duration of each of them, the spacing between each sinusoid D1, D2 ... D ,, and detecting the Missing tooth 20 (the gap due to the missing tooth This being longer), it is possible to determine the rotation speed of the motor, the direction of rotation of the motor and the angular position of the crankshaft. As illustrated in FIG. 2, the signal B has a minimum BMIN1 and a maximum BMAX1. The detection of the passage of the teeth T1, T2... T, and the recesses Ci, C2... by detecting the passage of the signal B above (respectively below) a detection threshold S1 placed between the minimum BMIN1 and the maximum B MAXI, for example equal to S1 = kl * (B MAXI BMIN1) I k1 being a constant, for example equal to 0.50. For purposes of explanation, the signal B illustrated in FIG. 2 comprises a single minimum BMIN1 and a single maximum B IN1 MAX. In reality, the signal B has a plurality of minimums BmiNi and a plurality of maximums BMAXi and the detection threshold If continuously adapts according to the minimums and the maximums so as to be always equal to = k1 * (BmAxi BmiNi) - This method of adaptation of the detection threshold Si is known to those skilled in the art, see the application for Patent FR 2 985 035 A1 filed by the applicant which describes the same method of adaptation of the detection threshold but applied to a camshaft sensor.
    [0004] 3021739 3 For crankshaft sensor 16 applications on vehicles equipped with the "Stop and Restart" or "Stop & Go" function in English, that is to say vehicles, for which, when they are when stopped (at low beam, for example) the engine is stopped temporarily, it is necessary when restarting the vehicle, to know precisely the position of the crankshaft. This constraint aims to comply with polluting emission standards and to limit fuel consumption. When stopping the engine, because of the inertia of the latter, the crankshaft 16 performs several back and forth before stopping completely. The crankshaft sensor 10 is therefore not only able to increment the number of teeth and hollows it detects but also to decrement it. Moreover, during the stopping phase of the engine d (see FIG. 4), which can last a few minutes, the sensor 10 remains energized and the signal B has a progressive aperiodic drift, that is to say a slope comprising no rising or falling edge, referred to as ATAR thermal drift (see Figure 4). During the restart R of the motor, the signal B is shifted in value, and presents a new minimum BMIN2 and a new maximum BMAX2. It is then necessary to adapt the detection threshold 51 according to these new values BMIN2 and -R MAX2 in order to detect, when the motor is restarted, the passage of the third and fourth teeth T3, T4 and the third and fourth hollow C3 , C4. If the detection threshold Si is not adapted to the new minimum values BMIN2 and maximum B MAX2, and is, for example, below the minimum value BMIN2 (as illustrated in FIG. 4), then during the restart, no tooth , (neither 13 nor T4) and no trough, (neither C3 nor C4) can be detected and the position of the crankshaft can not be determined.
    [0005] According to the prior art, it is known during the development phase of the sensor 10 to determine a Sun initialization detection threshold. The initialization detection threshold Sun- is applied as soon as the rising edge and the falling edge of the first tooth T1 are detected, when the engine is started cold. Then again according to the prior art, once a maximum value BMAX1 and a minimum value BMIN1 of the magnetic field have been measured by the sensor 10, in other words, once the first tooth Ti passed in front of the sensor 10 , then a detection threshold of use Si 'is applied. It has the value S1, = k2 * (BmAx1-BmiN1) where k2 is a constant between 0 and 1 (k2 can be equal to k1). This utilization detection threshold Sv is greater than the initialization detection threshold SINIT and is applied as soon as the second tooth T2 is detected (rising edge or falling edge, depending on which edge is first).
    [0006] 3021739 4 For a crankshaft sensor 16 fitted to a "Stop and Restart" engine, it is known from the prior art, when the engine is warm restarted (detection of the passage of a first tooth), to apply the method of the prior art described above. That is, to use an initialization detection threshold Sun-, according to the example illustrated in FIG. 4, to the passage of the first tooth after the restart, that is to say to the passage of the 3rd tooth T3. Then, after the passage of the third tooth 13, to calculate a utilization detection threshold equal to: Sv = k2 * (BMAX2-BmIN2) - This new detection threshold S1 is then applied (in the example illustrated in FIG. FIG. 4) at the passage of the second tooth after the warm restart, it is in the example illustrated in FIG. 4 of the rising edge of the 4th tooth T4. However, this method is not reliable when there are vibrations, or oscillations of the crankshaft at warm start. These vibrations and oscillations create extreme values of the signal B which do not correspond to the minimums and maximums of the passage of the third and fourth teeth 13, T4 or the third and fourth recesses C3, C4 in front of the target 14. This is false. the calculation of the new detection threshold S1 and impacts the accuracy on the determination of the position of the crankshaft 16. However, unlike the cold start of the vehicle, for which several crankshaft turns are tolerated 16 in order to accurately estimate the threshold of S1 detection, and accurately detect the passage of each tooth and each hollow in front of the sensor 10 for hot restart, for reasons of compliance with anti-pollution standards and reduced consumption (fastest restart possible in conditions of consumption and pollutant emissions optimal), it is necessary to know precisely the position of the crankshaft 16 and therefore to estimate quickly and precisely the value of the new detection threshold S1, and this dice the first rising edge of the third tooth T3. This is the purpose of the present invention. The invention proposes a method of adapting a detection threshold of a crankshaft sensor of a motor vehicle improving the accuracy of said sensor during the warm restart of the engine. The invention applies more particularly to vehicles equipped with the "Stop and Restart" function. The invention proposes a method of adapting a detection threshold of a magnetic field sensor for a crankshaft of a motor vehicle, said vehicle comprising at least one crankshaft and a toothed target associated with said crankshaft, said sensor delivering a signal of magnetic field variations having two states such that: - State 1: when the crankshaft is rotating: the signal comprises, ascending fronts and falling fronts, representative of the teeth and troughs of the target, 3021739 5 - State 2 : when the crankshaft is stopped: the signal has an aperiodic progressive drift. The adaptation method comprising, for the state 1, a step of detection of the rising edges and the falling edges of the signal, as a function of at least one detection threshold, and according to the invention, said method comprises for the state 2 the following steps: - step 1: detection of the stop of the crankshaft by the absence for a predetermined duration of detection of rising edges and falling edges on the signal as a function of the detection threshold, - step 2: after the duration predetermined, measuring the value of the signal at 10 successive intervals, - step 3: for each interval, calculating the variation of the value of the signal on said interval and, - step 4: calculating a new detection threshold by the adding to the detection threshold previously used on the preceding interval of the variation of value of the signal thus calculated on said preceding interval, - step 5: repetition of steps 3 and 4 as long as no rising edge ant or descending front is detected according to the antheventeenth detection threshold used before adding to step 4. The adaptation method according to the invention allows during a stopping phase of the engine (crankshaft when stopped), during which the magnetic field sensor remains energized (ie: current supplied), that is to say for state 2, to adapt the detection threshold to a new value taking into account the the thermal drift that the signal undergoes during said stopping phase of the engine. Thus, the invention has the advantage, compared to the prior art, of using a new detection threshold adapted to the new extrema of the signal, when the motor is restarted. This new detection threshold is applicable from the first tooth encountered, whether it is an upward or downward front, which was not possible with the method of the prior art. The adaptation method according to the invention therefore allows an optimized restart of the engine in terms of fuel consumption and pollutant emission. According to a preferred embodiment, the successive intervals are of identical duration. Advantageously, the predetermined duration is proportional to a rotation speed of the crankshaft or the predetermined duration is at least equal to a duration comprising an ascending front and a falling edge before stopping the crankshaft. The invention also relates to a device for measuring the position of the crankshaft of a motor vehicle engine, said device comprising: a crankshaft, a toothed target associated with said crankshaft, a magnetic field sensor, located at near the toothed target, said sensor delivering a magnetic field variation signal due to the rotation of the toothed target, such that: when the crankshaft is rotating: the signal comprises ascending fronts and falling fronts representative of teeth and hollows of the target, when the crankshaft is at a standstill: the signal has an aperiodic progressive drift, - signal processing means delivered by the sensor, according to the invention said processing means are adapted to: detecting rising edges and falling edges of the signal, as a function of at least one detection threshold; detecting the stoppage of the crankshaft by the absence with a predetermined duration of detection of rising edges and falling edges on the signal, - after the predetermined duration, measuring the value of the signal at successive intervals, - for each interval, calculating the variation of the signal value, - for each interval, calculating a new detection threshold by adding to the detection threshold previously used on the previous interval, the variation of value of the signal calculated on said preceding interval, - detecting the rotation of the crankshaft, using the antépénultième threshold of calculated detection. The invention also applies to a magnetic field sensor for a crankshaft of a motor vehicle, said sensor being associated with processing means and delivering a magnetic field variation signal to said processing means such as: when the crankshaft is in rotation: the signal comprises ascending fronts and descending fronts, representative of the teeth and hollows of the target, - when the crankshaft is at a standstill: the signal has an aperiodic progressive drift, According to the invention, the processing means are adapted to: - detect rising edges and falling edges of the signal, as a function of at least one detection threshold, - detecting crankshaft stoppage by the absence during a predetermined duration of detection of ascending fronts and falling edges on the signal, - after the predetermined duration, measuring the value of the signal at successive intervals, - for each that interval, calculate the variation of value of the signal, - for each interval, calculate a new detection threshold by adding to the detection threshold previously used on the preceding interval, the variation of value of the signal computed on said preceding interval , 10 - detecting the rotation of the crankshaft, using the calculated anthepthultieth detection threshold. Finally, the invention relates to any motor vehicle comprising a sensor according to the characteristics listed above. Other characteristics and advantages of the invention will be clear from reading the following description and from examining the appended drawings in which: FIG. 1, explained above, is a diagrammatic sectional view, showing a sensor 10 crankshaft 16 and its associated target 14, FIG. 2, explained above, represents, according to the prior art, the signal B delivered by the sensor 10 as a function of the rotation angle of the crankshaft 16, as well as the detection threshold S1 of the rising and falling fronts, without thermal drift, Figure 3, explained above, which represents the position of the teeth Tl, 12 ... T, and recesses C1, 02 ... C, of the target 14 relative to the B signal delivered by the sensor 10 of Figure 2, Figure 4 explained above, represents the signal B delivered by the sensor 10 according to the rotation angle 0 of the crankshaft 16, and the detection threshold S1 of rising fronts and in the presence of an ATAR thermal drift, according to the prior art, FIG. 5 represents the signal B delivered by the sensor 10 as a function of the rotation angle 0 of the crankshaft 16, as well as the adaptation of the threshold In the presence of an ATAR thermal drift, according to the invention, FIG. 6 shows the position of the teeth T2, T3 and the recesses C2, 03 of the target 14. relative to the signal B delivered by the sensor 10 of FIG.
    [0007] The invention proposes a method of adapting the detection threshold Si of rising edges and falling edges of the signal B delivered by the magnetic field sensor associated with the crankshaft 16. Said sensor 10, equipping a "Stop and Restart" engine 1, when the crankshaft 16 is rotating (rotating motor), the signal B comprises ascending fronts and descending fronts, representative of the teeth T1, T2. ... T, and hollows C1, C2 ... C, of the target 14 which pass in front of said sensor 10, 10 - State 2: when the crankshaft 16 is stopped (engine stopped, but sensor 10 under tension ), the signal has an aperiodic progressive drift, which is an ATAR thermal drift, due to the effect of the temperature prevailing in and around the sensor 10. For the state 1, the detection of the rising and falling edges of the signal B 15 is carried out according to n at least one detection threshold S1 according to the prior art described above. For the state 2, the method according to the invention proposes firstly to detect the stopping of the motor A by means of the magnetic field sensor 10. The magnetic field sensor 10 remains energized during this motor stopping phase d. Detection of the stopping of the motor A is effected by the absence of detection by the upstream edge and the falling edge sensor for a predetermined duration AtA (see FIG. 5). This predetermined time AtA must be long enough, that is to say adapted, for, under operating conditions of the engine (crankshaft 16 in rotation), to be able to detect at least one rising edge and at least one falling edge of the signal. B. This predetermined time AtA may be equal to, for example 1 second or be proportional to the rotational speed of the crankshaft 16. Once the engine stop has detected, the sensor 10 continues to measure the value of the magnetic field that it therefore receives and delivers a signal B to signal processing means 13. The signal processing means 13 then measure the value of the signal B at intervals 311, 312, 313, At; ... successive (see Figure 5). These intervals 311, 312, 313, 31 may be regular, of equal duration, for example to one second. For each interval 311, 312, 313, 314 ... 31, the processing means 13 calculate the variation A1, 02, 3.3, 34 ... A of the value of the signal B between the beginning of the interval At, and the end of the interval 31 ,. This variation A A A A A of the value of -1, -2, -3, signal B corresponds to the thermal drift ATAR, caused by the effect of the temperature prevailing under the bonnet of the vehicle on the signal B delivered by the sensor 10.
    [0008] 3021739 9 Then for each interval 31 ,, the detection threshold Si is equal to the sum between the detection threshold SHI and the variation of the value A_, the signal B of the previous interval 31, -1. Thus, for the first iteration, as illustrated in FIG. 5, after the predetermined stopping time AtA of stopping detection of the motor A, the value of the signal B is measured at the first point P1, then the value of the signal is measured at the second point. P2, that is to say at the beginning and at the end of the first interval 311. The first variation of value of the signal B, Ai = V2-V1 is calculated. with: 10 0,: first variation of value of the signal B (between the first point P1 and the second point P2), V1: value of the signal B at the first point P1, V2: value of the signal B at the second point P2. Then a second detection threshold S2, after the first interval 311 is calculated and is equal to: S2 = + with:: first variation of value of the signal B (between the first point P1 and the second point P2), and 20 Si : the detection threshold used previously, that is to say, before stopping the motor A and equal to, for example: S1 = kl * (BmAxi - Bm IN1) and: k1: a constant between 0 and 1 , BMAX1 and BMIN1 - the extrema of the signal, respectively the maximum and the minimum of the signal B, before stopping the motor A. Then these calculations are repeated, for the second and third points P2 and P3, ie for the second interval 312. The second signal variation B, 02 on the second interval 312 is equal to: 3.2 = V3 - V2 And, a third detection threshold S3, after the second interval 312 is equal to: S3 = S2 + with: 35 02: second variation of value of the signal B between the second point P2 and the third point P3, V2: value of the signal B at the second point P2, 3021739 V3: value of the signal at the third point P3. In FIG. 5, at the fourth point P4, the fourth detection threshold S4 is: S4 - 53 + 3.3 with: 33 - V4 V3: third variation in value of the signal B between the third point P3 and the fourth point P4 , V3: value of the signal B at the third point P3, V4: value of the signal at the fourth point P4.
    [0009] Then at the fifth point P5, the fifth detection threshold S5 is: 55 = 54 + A4 with: 3.4 = V5 - V4: fourth variation of value of the signal B between the fourth point P4 and the fifth point P5, V4 : value of signal B at the fourth point P4, V5: value of the signal at the fifth point P5. These steps are repeated n times, as long as the restart of the engine R is not detected. Thus, on the interval 31n: Sn = Sn-1 + 4-1 1n_1 = Vn-Vn-1 with: Sn: detection threshold on the interval 31n, Sn_i: detection threshold on the interval Atn- i 25 year-1: value change over the interval 34_1, Vn: value of the signal at the point n, Vn_i: value of the signal at the point n-1. It should be noted that the threshold Sn of the interval Atn is always calculated from the threshold Sn_l and the variation an-1 of the value of the signal B, calculated on the previous interval 34_1. Indeed, the variation An of value of the signal B on the interval Atn, is not calculable as long as the interval Atn is not completed. However, the exact time of the restart of the engine R is unknown and can be in any interval 311, 312, 313, 314 ... 31,. Restarting the motor R increases the values of the signal B, following the passage of a tooth (in this case the 3rd tooth 13, as shown in FIG. 6) and false (as explained below). calculating the variation AAA of the value of the signal B over this interval. The threshold of --1, -2, -3, 3021739 11 detection S1, S2, S3, S4 ... If calculated on this interval 311, 312, 313, 314 ... 31, is therefore overestimated. In FIG. 5, the engine restart R is at the end of the fourth interval 314, causing a significant increase in the slope of the signal B. The fourth variation 34 of the signal B is no longer only representative of the 3TAR thermal drift. Part of this variation is due to the restart of the motor R. The fourth detection threshold S4 calculated on this fourth interval 314 is therefore overestimated. When detecting the rising edge on the next interval, i.e. on the fifth gap 315, the invention proposes not to use the fourth detection threshold S4 (calculated on the preceding interval), since this one is overestimated, but to use the third detection threshold S3 calculated on the third interval 313, that is to say to use the penultimate threshold calculated. Of course, the third detection threshold S3 does not include the increase of the signal B due to the 3TAR thermal drift occurring on the fourth interval 314. The use of the third detection threshold S3 thus underestimates the impact of the drift However, since the slope gradient of the thermal drift is much lower than the slope gradient of the passage of a tooth, the invention judiciously proposes neglecting the thermal drift of the last interval in order not to overestimate the threshold of detection of the passage of a tooth following the engine restart R. The restart of the engine R is thus detected by the passage of the values of the signal B above the penultimate second (antepenultimate) detection threshold calculated.
    [0010] More precisely, on each interval Atn, the processing means 13 compare the value of the signal B with respect to the calculated third detection threshold that is to say with respect to the detection threshold Sn_2calculated over the interval 34. 2. It is important to note that the invention is based on the fact that the 3TAR thermal drift of the signal B during the stopping phase of the engine d is a slow physical phenomenon, of less impact on the signal B than the variation of the magnetic field of the passage of teeth. The adaptation method according to the invention thus rests on two hypotheses: the thermal drift of the signal B between the actual stopping of the motor A and the instant at which this stop is detected (after the predetermined duration AtA) is neglected, no variation of the signal B is calculated for the predetermined duration, and the thermal drift of the signal B during the last interval before the detection of the restart is also neglected. Thus, the threshold of detection, of the penultimate interval, and not that of the last interval is used to detect the restart of the motor on the current interval.
    [0011] The invention has the advantage over the prior art of estimating the variation of the detection threshold of thermal drift so that it can be used from the front of the first tooth after restarting. Then after the first tooth detected after the engine restart (ie the third tooth 13 in Fig. 6), the signal B being in state 1, the method 10 of adapting the detection threshold Sl , (S1, not shown in FIG. 5, since it is applicable for the detection of the second tooth after engine restart, which is not shown in FIG. 6) is identical to that of the prior art the detection threshold is adapted as a function of the minimum BMIN2 and the measured maximum BMAX2, so that: S1, = k1 * (BmAx2-BMJN2) The adaptation method according to the invention thus comprises, for the state 2 of the signal B the following steps: step 1: detection of the stop of the crankshaft 16 by the absence for a predetermined duration 3, tA of detection of rising edges and falling edges on the signal B as a function of the detection threshold If, 20 - step 2: after the predetermined duration 3, tA, measure the value V1, V2 ... V, of signal B at successive intervals 311, 312, 313, 314 ... 31i, - step 3: for each interval 311, 312, 313, 314 ... 31, calculation of the variation 30, 02, value of the signal B on said interval 311, 312, 313, 314 ... 31, and, 25 - step 4: calculation of a new detection threshold Sn by adding to the detection threshold previously used on the preceding interval 31n_i of the variation of value of the signal thus calculated over said previous interval Atn-1 I - step 5: repetition of steps 3 and 4 as long as no rising edge or falling edge is detected as a function of the last-mentioned second detection threshold Sn-2 before the addition to step 4. According to the invention, the processing means 13 associated with the sensor 10 are adapted to: - detect rising edges and falling edges of the signal B, as a function of at least one threshold detection device 3021739 13 - detecting the stop of the crankshaft 16 by absence for a predetermined period of time AtA of detection of rising edges and falling edges on the signal B, - after the predetermined duration AtA, measuring the value V1, V2 ... V, of the signal at 5 successive intervals 311, 312, 313, 314 ... 31i for each interval Otn, calculate the value variation B of the signal B, for each interval Otn, calculate a new detection threshold Sn by adding to the detection threshold previously used on the preceding interval of the variation An- , of value of the signal B calculated on said preceding interval - to detect the rotation of the crankshaft 16, by using the antépénultième detection threshold Sn_2calculé. The invention therefore makes it possible to take into account the effect of the thermal drift experienced by the signal delivered by the sensor when the engine is stopped in order to adapt the detection threshold of the teeth and troughs of the target to a new value that can detect more precisely than the methods of the prior art, the first tooth from the restart of the engine. The adaptation method according to the invention therefore allows an optimized warm restart of the engine in terms of fuel consumption and emission of pollutants.
    权利要求:
    Claims (7)
    [0001]
    REVENDICATIONS1. Method for adapting a detection threshold (S1) of a magnetic field sensor (10) for a crankshaft (16) of a motor vehicle, said vehicle comprising at least one crankshaft (16), a target (14) toothed joint associated with said crankshaft (16), said sensor (10) delivering a signal (B) of magnetic field variations having two states 5 such that: - State 1: when the crankshaft (16) is rotating: the signal (B) comprises, ascending fronts and falling fronts, representative of teeth (Ti, T2 ... T,) and recesses (C1, C2 ... C,) of the target (14), - State 2: when the crankshaft (16) is at a standstill: the signal (B) has an aperiodic progressive drift (3.TAR), the adaptation method comprising for the state 1, a step of detection of the ascending fronts and the falling fronts of the signal (B), as a function of at least one detection threshold (Si), said method being characterized in that it comprises for state 2 the following steps: 5 - step 1: detection of the stop of the crankshaft (16) by the absence for a predetermined duration (31A) of detection of rising edges and falling edges on the signal (B) as a function of the detection threshold (Si) - step 2: after the predetermined duration (31A), measuring the value (V1, V2 ... V,) of the signal (B) at successive intervals (311, 3.t2, 313, 314 ... 34 Step 3: for each interval (311, 312, 313, 314 ... 34 calculation of the variation (0 ,, D2, 3,3, 3.4 ... 0,) of the signal value (B) and, step 4: calculation of a new detection threshold (Sn) by adding to the detection threshold previously used on the preceding interval (31, -, _ 1) of the variation of value of the signal calculated on said preceding interval 25 (31, -, _,), - step 5: repetition of steps 3 and 4 as long as no rising edge or falling edge is detected as a function of the anthepthultieth detection threshold (Sn-2) used before the added in step 4.
    [0002]
    2. Adaptation method according to the preceding claim characterized in that the successive intervals (311,
    [0003]
    3.t2, 313, 314 ... 31) are of identical duration. 3. Adaptation method according to claim 1 or 2, characterized in that the predetermined duration (31A) is proportional to a rotational speed of the crankshaft (16).
    [0004]
    4. Adaptation method, according to claim 1 or 2, characterized in that the predetermined duration (31A) is at least equal to a duration comprising an ascending front and a falling edge before stopping the crankshaft (16).
    [0005]
    5. A device for measuring the position of the crankshaft (16) of a motor vehicle engine, said device comprising: - a crankshaft (16), - a toothed target (14) associated with said crankshaft (16), - a sensor Magnetic field sensor (10), located near the toothed target (14), said sensor (10) providing a magnetic field change signal (B) due to the rotation of the toothed target (14), such as: when the crankshaft (16) is in rotation: the signal (B) comprises ascending fronts and descending fronts, representative of the teeth (Ti, T2 ... T,) and hollows (Cl, 02 ... C,) of the target (14), when the crankshaft (16) is stopped: the signal (B) has an aperiodic progressive drift (3TAR), - processing means (13) of the signal (B) delivered by the sensor (10), said device being characterized in that said processing means (13) are adapted to: - detect rising edges and falling edges of the signal (B), as a function of at least one detection threshold (S1), - detecting the stopping of the crankshaft (16) by the absence for a predetermined duration (31A) of detection of ascending fronts and descending fronts on the signal (B), - after the predetermined duration (314, measuring the value (V1, V2 ... V,) of the signal (B) at successive intervals (311, 3t2, 313, 314 ... 31,), - for each interval (31,), calculate the variation (An) of the signal value (B), - for each interval (31,), calculate a new detection threshold (Sn) by adding to the detection threshold previously used on the preceding interval (31, -, _,), of the variation of value of the signal (B) calculated on said preceding interval (31n-1), - detecting the rotation of the crankshaft (16), using the antithenetic threshold of detection (Sn_2) calculated. 5
    [0006]
    6. sensor (10) of magnetic field for crankshaft (16) of a motor vehicle, said sensor (10) being associated with processing means (13) and delivering a signal (B) of magnetic field variations to said processing means ( 13) such that: - when the crankshaft (16) is rotating: the signal (B) comprises, ascending fronts and descending fronts, representative of the teeth (Ti, T2 ... T,) and hollows (C1 , C2 ... C,) of the target (14), - when the crankshaft (16) is at a standstill: the signal (B) has an aperiodic progressive drift (3TAR), said sensor (10) being characterized in the processing means (13) are adapted to: - detect rising edges and falling edges of the signal (B), as a function of at least one detection threshold (S1), - detecting the stop of the crankshaft (16) by the absence for a predetermined duration (31A) of detection of rising edges and falling edges on the signal (B), - apr at the predetermined time (31A), measure the value (V1, V2 ... V,) of the signal at successive intervals (311, 312,313, 314 ... 34 - for each interval (Atn), calculate the variation (An ) of the signal value (B), for each interval (34), calculating a new detection threshold (Sn) by adding to the detection threshold previously used (Sn_i) over the previous interval (34_1), the variation (3, n_i) of the value of the signal (B) calculated on the said preceding interval (34-1), - detecting the rotation of the crankshaft (16), using the calculated antépénultième threshold 30 (Sn-2) .
    [0007]
    7. Motor vehicle comprising a sensor (10) according to the preceding claim.
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    CN105157558A|2015-12-16|
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    JP2015232329A|2015-12-24|
    CN105157558B|2019-06-14|
    US20150346004A1|2015-12-03|
    US10215591B2|2019-02-26|
    JP6525744B2|2019-06-05|
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    优先权:
    申请号 | 申请日 | 专利标题
    FR1455013A|FR3021739B1|2014-06-03|2014-06-03|METHOD FOR ADAPTING A SENSOR DETECTION OF A CRANKSHAFT SENSOR FOR A MOTOR VEHICLE|FR1455013A| FR3021739B1|2014-06-03|2014-06-03|METHOD FOR ADAPTING A SENSOR DETECTION OF A CRANKSHAFT SENSOR FOR A MOTOR VEHICLE|
    US14/727,356| US10215591B2|2014-06-03|2015-06-01|Method for adapting a detection threshold of a crankshaft sensor for motor vehicle|
    CN201510294527.4A| CN105157558B|2014-06-03|2015-06-02|For adjusting the method for being used for the detection threshold value of crankshaft sensor of motor vehicles|
    JP2015113104A| JP6525744B2|2014-06-03|2015-06-03|Method of adapting detection threshold of crankshaft sensor for motor vehicle|
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