JP4735737B2 - Engine stop / start control device - Google Patents

Description

  The present invention relates to an engine stop / start control device.

  2. Description of the Related Art Conventionally, there is known an engine control system having a so-called idle stop function that detects an operation for stopping or starting such as an accelerator operation or a brake operation to automatically stop and restart an engine. By this idle stop control, effects such as engine fuel consumption reduction are achieved.

  As a starter drive control at the time of engine restart, a pinion provided on the starter motor is connected to the crankshaft of the engine in preparation for the next engine restart during the inertial rotation of the engine after the engine is automatically stopped. It has been proposed that the ring gear connected to the gear is previously engaged (see, for example, Patent Document 1 and Patent Document 2). By doing so, the engine is restarted promptly, and the meshing sound when the pinion bites into the ring gear is suppressed.

JP 2007-107527 A JP 2008-510099 A

  When engaging the pinion and the ring gear during the inertial rotation of the engine after the engine has been automatically stopped, in order to minimize the meshing noise, the above-mentioned is necessary in the extremely low rotational speed region immediately before the inertial rotation of the engine stops. It is desirable to engage. However, for example, in a generally used electromagnetic pickup type rotation sensor, the resolution is limited by the tooth spacing of the pulsar, resulting in accurate engine rotation speed (ring gear rotation speed) in the extremely low rotation speed range. There is concern that it cannot be detected well. In such a case, the pinion biting timing may not be controlled to an optimal timing.

  The present invention has been made in order to solve the above-described problems, and can perform the engagement of the pinion and the ring gear at an optimal timing, and thus can suppress the engagement noise between the pinion and the ring gear. The main object is to provide a stop / start control device.

  The present invention employs the following means in order to solve the above problems.

The present invention has an automatic stop start function that automatically stops the engine when a predetermined automatic stop condition is satisfied, and then starts cranking by a starter and restarts the engine when the predetermined restart condition is satisfied. The engine is stopped and restarted when cranking is performed with the starter pinion meshing with a ring gear connected to the output shaft of the engine when the engine is restarted, and the meshing is released after the cranking is completed. The present invention relates to a control device. In particular , the first configuration includes a rotational speed calculation means for calculating an engine rotational speed based on a detection signal of a rotation sensor that detects the rotation of the output shaft, and the engine is inertially rotated after the engine is automatically stopped. Prediction means for predicting the rotational trajectory of engine inertia rotation based on the engine rotational speed calculated by the rotational speed calculation means during the period, and timing for meshing the pinion with the ring gear based on the rotational trajectory predicted by the prediction means And a control means for controlling.

  In short, in the idle stop control, the pinion may be engaged in advance with the ring gear during the engine inertia rotation after the engine is automatically stopped. In this case, in order to suppress the meshing noise between the pinion and the ring gear, it is desirable to perform the meshing in a predetermined engine rotation speed region (very low rotation speed region) where the sound suppression effect is high. However, the rotation sensor that detects the rotation of the engine output shaft has a limit in the engine rotation speed at which a detection signal can be output, and the engine rotation speed in the extremely low rotation speed region may not be calculated with high accuracy. In such a case, the meshing between the pinion and the ring gear cannot be performed at an optimal timing, and the meshing sound may increase.

In view of this point, in the first configuration , during inertial rotation after automatic engine stop, a calculated value based on the detection signal of the rotation sensor is used to predict the engine rotation speed in a region that cannot be calculated from the detection signal. Further, the drive of the pinion is controlled so that the meshing is performed at a desired engine rotation speed within the prediction result region. As a result, the engagement between the pinion and the ring gear can be carried out at an optimum timing, and as a result, the engagement sound when the pinion and the ring gear are engaged can be suppressed.

Specifically, as in the second configuration , the rotation speed calculation means calculates an instantaneous rotation speed as the engine rotation speed calculated from the time required for rotation of the output shaft at a predetermined rotation angle, The prediction means predicts the rotation trajectory based on a plurality of instantaneous rotation speeds in a period in which the instantaneous rotation speed is in a decreasing tendency. The instantaneous rotational speed is repeatedly increased and decreased. In the period in which the instantaneous rotational speed tends to decrease, the gradient of the engine rotational speed toward the speed zero, that is, the rotational trajectory toward the speed zero can be predicted. Here, the instantaneous rotational speed used for the prediction of the rotational trajectory need only include at least a plurality of instantaneous rotational speeds during a period in which the instantaneous rotational speed tends to decrease, and it can be rotated only by the instantaneous rotational speed during the same period. The trajectory may be predicted, or the rotational speed may be predicted by adding the instantaneous rotational speed immediately before the same period (for example, the instantaneous rotational speed during a period in which the instantaneous rotational speed tends to increase).

During the period in which the instantaneous rotation speed monotonously decreases toward zero, that is, the period in which the instantaneous rotation speed does not change in the upward direction and changes only in the decreasing direction, the engine rotation speed does not increase, so the rotation trajectory is accurately predicted. Cheap. Therefore, as in the third configuration , when the instantaneous rotation speed reaches a monotonous decrease period in which the instantaneous rotation speed decreases monotonically toward zero speed, the rotation trajectory may be predicted based on the plurality of instantaneous rotation speeds. By doing so, the prediction accuracy of the rotation trajectory of the engine inertia rotation can be improved.

  Here, specifically, the monotonous decrease period is, for example, a period after reaching the final top dead center when the inertial rotation of the engine has not yet reached zero speed and the forward rotation state is maintained.

In order to suppress the meshing noise between the pinion and the ring gear, it is preferable that the rotation speed region be as close to zero as possible. In order to predict the rotation speed near zero speed, it is desirable to use a value as close as possible to the region to be predicted among the rotation speeds detectable by the rotation sensor. Therefore, as in the fourth configuration , the rotation trajectory may be predicted when the engine rotation speed due to the inertial rotation of the engine decreases to a predetermined rotation speed.

When the inertial rotation of the engine decreases and the engine rotation speed becomes a very small value, the rotation sensor cannot detect the passage of the tooth portion (in the case of the electromagnetic pickup type, the magnetic field change is less likely to occur). Therefore, the engine speed cannot be calculated from the sensor detection signal. Further, from the viewpoint of the prediction accuracy, it is desirable that the rotation trajectory is predicted based on the lowest possible rotation speed among the rotation speeds at which the engine rotation can be properly detected by the rotation sensor. Therefore, as in the fifth configuration , the rotation sensor detects the passage of a plurality of teeth provided in a pulser that rotates with the output shaft, and the rotation speed calculation means The engine rotation speed is calculated based on the pulse interval of the detection signal output from the rotation sensor in response to the passage, and the prediction means immediately before the rotation speed region where the rotation sensor cannot detect the passage of the tooth portion. The rotation trajectory may be predicted by a sensor detection signal at.

In the sixth configuration , the predicting means includes, as the rotation trajectory, a slope of a monotonically decreasing period in which the instantaneous rotational speed monotonously decreases toward zero speed, and a period until the monotonic decreasing period during inertial rotation of the engine. Calculate the required time. According to this configuration, when the slope of the monotonically decreasing period and the time required until the same period are calculated, it is possible to predict the rotational trajectory in the rotational speed region that cannot be calculated from the sensor detection signal. By calculating the inclination and the required time using the inertial rotational speed at the time of a high engine speed, the engine rotational speed can be predicted at an earlier time. The required time is calculated based on the engine speed at the time when the slope of the monotonically decreasing period is calculated, for example.

Specifically, for the sixth configuration , for example, when the slope of the monotonically decreasing period is calculated from the instantaneous rotational speed that is higher than the engine speed that can be taken in the monotonically decreasing period, the predetermined rotational speed that is predicted based on the slope is calculated. The arrival time at is delayed by an offset amount corresponding to the instantaneous rotational speed at the time of calculating the inclination.

From the viewpoint of sound suppression during meshing, it is desirable to perform meshing at a point in time when the inertial rotation of the engine is zero, or just before or after it becomes zero. Therefore, as in the seventh configuration , the timing at which the actual engine rotation speed becomes zero is estimated based on the rotation trajectory predicted by the prediction means, and the pinion meshing process is performed at or near the estimated timing. It is good to carry out. In particular, it is desirable to set the timing at which the speed first becomes zero by inertial rotation after automatic engine stop. In such a case, the pinion and the ring gear can be meshed at the earliest possible timing, which is preferable for reliably completing the meshing before the next engine restart request.

In a configuration in which the pinion and the ring gear are not in contact with each other when the pinion starts to rotate, the pinion and the ring gear are actually engaged from the start of the engagement operation of the pinion (for example, the movement toward the ring gear). It takes time until it is brought into contact. Therefore, in order to mesh the pinion and the ring gear at an optimum timing, it is necessary to start the operation of the pinion earlier than the timing by the time required for the meshing operation. Therefore, as in the eighth configuration , the operation start timing of the pinion may be determined based on the rotation trajectory predicted by the prediction means and the engagement operation time required for the engagement operation of the pinion. By doing so, the effect that the pinion and the ring gear mesh with each other at an appropriate time can be suitably obtained.

A ninth configuration includes storage means for storing the rotation trajectory predicted by the prediction means, and the control means engages the pinion with the ring gear based on the past rotation trajectory stored in the storage means. Control the timing to match. According to this configuration, it is not necessary to predict the rotation trajectory during engine inertia rotation based on the sensor value every time the engine is automatically stopped. At this time, it is desirable to use information on the rotational speed of the engine corresponding to the current operating state of the engine or the engine-driven auxiliary machine. This is because the rotation trajectory during engine inertia rotation varies depending on the operating state of the engine or the like.

The degree of decrease in rotational speed during inertial rotation of the engine varies depending on the operating state of the engine and the auxiliary equipment driven by the engine. In view of this point, the tenth configuration changes the predicted rotation trajectory based on the engine rotation speed calculated by the rotation speed calculation means, based on the operating state of the engine or an auxiliary machine driven by the engine. By doing so, it is possible to change the timing at which the pinion is engaged with the ring gear in accordance with the degree of decrease in the engine rotation speed caused by the difference in the operating state of the engine or the like. Therefore, it is suitable for causing the pinion to be engaged with the ring gear at an optimal timing.

1 is an overall schematic configuration diagram of an engine control system. The time chart which shows transition of an actual rotational speed and an instantaneous rotational speed. The flowchart which shows the process sequence of the starter drive process at the time of engine restart.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. This embodiment is embodied in an engine stop / start control device of an engine control system applied to an on-vehicle four-cylinder engine. In the control system, fuel injection amount control, ignition timing control, idle stop control, and the like are performed with an electronic control unit (hereinafter referred to as ECU) as a center. FIG. 1 is a block diagram showing the overall outline of this control system.

  In FIG. 1, the starter 10 is provided with a motor 11, and a motor switch unit SL <b> 1 that switches between energization / non-energization of the motor 11 between the motor 11 and the battery 12. The motor switch unit SL1 is connected to an SL1 drive relay 13 that switches on / off of the motor switch unit SL1 based on a control signal.

  Connected to the motor 11 is an actuator SL2 including a pinion shaft 14 that is rotationally driven by the motor 11 and a coil 15 that reciprocates the pinion shaft 14 in the axial direction by energization / non-energization. A pinion 16 is supported at one end of the pinion shaft 14, and the pinion 16 is integrated with a one-way clutch 17 that intermittently transmits power between the pinion shaft 14 and the pinion 16. The pinion 16 is disposed in a non-contact state with respect to the ring gear 22 connected to the crankshaft 21 of the engine 20 when the coil 15 is not energized.

  Between the plunger coil 15 and the battery 12, an SL2 drive relay 18 that switches between energization / non-energization of the coil 15 based on a control signal is provided. When an ON signal is input to the SL2 drive relay 18 and the SL2 drive relay 18 is turned on, power is supplied from the battery 12 to the coil 15, and the pinion shaft 14 is pushed out toward the ring gear 22. As a result, the pinion 16 is engaged with the ring gear 22.

  When the off signal is input to the SL2 drive relay 18 and the SL2 drive relay 18 is turned off, the energization from the battery 12 to the coil 15 is cut off, and the pinion shaft 14 is moved to the ring gear 22 by the biasing force of a spring (not shown). It is displaced in the direction opposite to the direction toward. Due to the displacement of the pinion shaft 14, the engagement between the pinion 16 and the ring gear 22 is released.

  When the engine speed (rotational speed of the ring gear 22) becomes higher than the rotational speed of the pinion 16 when the engine is started and the pinion 16 is driven to rotate by the ring gear 22, the one-way clutch 17 is brought into a non-coupled state and the pinion 16 , The rotation of the pinion 16 is not transmitted to the pinion shaft 14. Thereby, it is avoided that the motor 11 is rotationally driven by engine power.

  Further, the present system is provided with a crank angle sensor 23 that outputs a rectangular crank angle signal for each predetermined crank angle of the engine 20 (for example, at a cycle of 30 ° CA). The crank angle sensor 23 includes a pulsar (rotating disc) 24 that rotates integrally with the crankshaft 21 and an electromagnetic pickup unit 25 provided in the vicinity of the outer periphery thereof. On the outer periphery of the pulsar 24, protrusions 26 are provided at predetermined crank angle intervals (for example, 30 ° CA intervals). Note that a part of the pulsar 24 is provided with a missing tooth portion in which a plurality of protrusions (for example, protrusions for two teeth) are missing. When the pulsar 24 rotates with the rotation of the crankshaft 21, the detection signal (NE signal) from the electromagnetic pickup 25 every time the protrusion 26 of the pulsar 24 approaches the electromagnetic pickup 25 (basically every 30 ° CA). ) Is output. Based on the pulse width of the NE signal, the rotational speed NE of the engine 20 is calculated. The crank angle sensor 23 corresponds to the rotation sensor of the present invention.

  In addition, the present system includes an IG switch 19 that switches to a state in which power from the battery 12 is supplied to the motor 11 and the coil 15 based on a key operation of the driver, and a cooling water temperature sensor 27 that detects the temperature of engine cooling water. Various sensors are provided.

  The ECU 30 is an electronic control device including a known microcomputer or the like. Based on detection results of various sensors provided in the system, the ECU 30 performs intake air amount control, fuel injection amount control, idle stop control, and the like. Various engine controls and drive control of the starter 10 are performed. Regarding the drive control of the starter 10, the ECU 30 includes an output port P1 that outputs an on / off signal of the SL1 drive relay 13 and an output port P2 that outputs an on / off signal of the SL2 drive relay 18, and the output port P1. , P2 to switch the energized state of the motor 11 and the coil 15 respectively.

  The idle stop control performed in the above system configuration will be described in detail. The idle stop control is to automatically stop the engine 20 when a predetermined stop condition is satisfied during the idling operation of the engine 20 and restart the engine 20 when a predetermined restart condition is satisfied thereafter. The engine stop condition is, for example, that the accelerator operation amount has become zero (becomes idle), that the brake pedal has been depressed, or that the vehicle speed has decreased to a predetermined value or less. Is included. The engine restart condition includes, for example, at least one of an accelerator depressing operation, a brake operation amount becoming zero, a charged state of the battery 12 being a predetermined reduced state, and the like. .

  As drive control of the starter 10, the ECU 30 basically starts energization of the coil 15 by first outputting an ON signal to the SL2 drive relay 18 in response to an engine start request. Thereby, the pinion 16 is pushed out from the starter 10, and the pinion 16 is engaged with the ring gear 22. Thereafter, an ON signal is output to the SL1 drive relay 13 to start energization of the motor 11. Accordingly, the pinion 16 is rotated with the rotation of the motor 11, and the ring gear 22 is rotated with the rotation, whereby cranking is performed.

  By the way, it is desirable that the restart after the automatic stop of the engine 20 is performed as soon as possible in response to the restart request. Further, when the pinion 16 is engaged with the ring gear 22, a meshing sound between the pinion 16 and the ring gear 22 is generated, which may cause discomfort to the driver. Therefore, in this embodiment, the engine 20 is restarted quickly, and the meshing between the pinion 16 and the ring gear 22 is performed when the engine 20 is restarted after the engine is automatically stopped in order to suppress the meshing noise between the pinion 16 and the ring gear 22. It is supposed to be carried out during a period in which the engine 20 is coasting after the automatic stop.

  Specifically, when there is a request for automatic stop of the engine 20, the fuel injection and ignition are stopped in accordance with the stop request, whereby the engine 20 rotates by inertia. During this inertia rotation period, an ON signal is output to the SL2 drive relay 18 to start energization of the coil 15. Thereby, the pinion 16 is pushed out in the axial direction of the pinion shaft 14, and the pinion 16 is engaged with the ring gear 22 before the engine 20 is completely stopped (in the inertial rotation period). When an engine restart request is made in this meshing state, an ON signal is output to the SL1 drive relay 13 to start energization of the motor 11. Thereby, the pinion 16 is rotationally driven, and the ring gear 22 is rotationally driven by the rotation, whereby cranking is performed.

  Here, in order to reduce the meshing noise as much as possible, immediately before the inertial rotation of the engine 20 stops, specifically, the relative rotational speed of the ring gear 22 with respect to the pinion 16 is within a predetermined extremely low rotational range (for example, 0 ± 100 rpm). It is necessary to mesh the two in a certain area. In particular, when the engine speed is zero, the sound suppression effect is high.

  On the other hand, in the electromagnetic pickup type rotation sensor used as the crank angle sensor 23 of the present embodiment, there is a limit to the engine rotation speed that can output the NE signal, and an extremely low rotation speed region (for example, 200 to 300 rpm or less) In some cases, it is not possible to accurately calculate the engine rotation speed in the region (1). This is because in the region where the engine rotation speed is extremely low, the rotation sensor cannot detect the passage of the tooth portion (protrusion 26), that is, the magnetic pick-up type sensor is less likely to cause a magnetic field change. However, the rotational speed region in which the meshing noise between the pinion 16 and the ring gear 22 can be suitably suppressed is included in the rotational speed region that cannot be calculated from the NE signal. Therefore, the drive control of the pinion 16 may not be properly performed at the engine speed calculated based on the NE signal. That is, the meshing between the pinion 16 and the ring gear 22 cannot be performed at the optimum timing, and as a result, the meshing sound may increase.

  Therefore, in the present embodiment, during the inertial rotation period after the engine 20 is automatically stopped, the rotation trajectory of the engine inertial rotation is predicted based on the engine rotation speed calculated based on the NE signal. Then, based on the predicted rotation trajectory, the timing for meshing the pinion 16 with the ring gear 22 is controlled. More specifically, the rotational trajectory is predicted based on the NE signal, and the rotational trajectory is calculated based on the rotational speed including a plurality of instantaneous rotational speeds during a period in which the instantaneous rotational speed is decreasing. Predict.

  Here, the instantaneous rotational speed is a value calculated from the time required for the rotation of the crankshaft 21 every time the crankshaft 21 rotates by a predetermined rotation angle (30 ° CA in the present embodiment).

  Hereinafter, the control of the meshing timing between the pinion 16 and the ring gear 22 will be described in detail with reference to FIG.

  FIG. 2 is a time chart showing the transition (one-dot chain line) of the actual engine speed (actual rotational speed NEA) and the transition (solid line) of the instantaneous rotational speed NES.

  First, fuel injection and ignition stop are executed as processing for automatically stopping the engine 20, whereby the engine 20 is coasting. In this case, as indicated by the alternate long and short dash line in FIG. 2, the actual rotational speed NEA gradually decreases. At the time of this deceleration, every time the top dead center is reached, the actual rotational speed NEA changes from falling to rising and again changes to falling.

  Further, as indicated by a solid line in FIG. 2, the instantaneous rotational speed NES also changes in accordance with the change in the actual rotational speed NEA. That is, when a predetermined period (180 ° CA) including the TDC of each cylinder is indicated by the unit waveform TB, the instantaneous rotational speed NES changes from falling to rising to falling in the unit waveform TB, and the unit waveform TB repeatedly appears. To do. Therefore, using this tendency, in the present embodiment, a plurality of instantaneous rotational speeds NES within the period TC in which the instantaneous rotational speed NES tends to decrease in the unit waveform TB (in FIG. 2, two points of time points A1 and B1). Based on the instantaneous rotation speed NES), the rotation trajectory of the inertia rotation speed after the calculation timing of the used instantaneous rotation speed NES is predicted.

  Specifically, for example, as shown in FIG. 2, a change in the engine rotational speed in the descending direction after the timings A1 and B1 by a linear function connecting the instantaneous rotational speed NES at the timings A1 and B1 immediately after the top dead center. Predict (orbit). Also, one point (B1 in FIG. 2) of the instantaneous rotational speed NES used for the trajectory prediction is used as a starting point, and a trajectory corresponding to a predetermined meshing rotational speed NEP (for example, zero) determined in advance from the starting point. The required time TP required up to the upper point P is calculated. Then, the push-out control of the pinion 16 is performed so that the time when the required time TP has elapsed from the starting point is the meshing timing tp1.

  In the case of performing trajectory prediction using a linear function, as shown in FIG. 2, the instantaneous rotational speed NES at the adjacent timing may be used, but it may be not adjacent. Moreover, you may use the instantaneous rotational speed NES in three or more timings. In this embodiment, the meshing rotation speed NEP is the rotation speed at which the pinion 16 and the ring gear 22 start to mesh. However, it may be the rotational speed when the meshing is completed.

  Further, in the present embodiment, when the instantaneous rotational speed NES reaches a period (monotonically decreasing period TDW) in which the instantaneous rotational speed NES monotonously decreases toward zero, the rotational trajectory is predicted based on a plurality of instantaneous rotational speeds NES. In this embodiment, the monotonous decrease period TDW is on the unit waveform TB before the inertial rotation of the engine 20 shifts from normal rotation to reverse and includes the final top dead center (final TDC) at the time of the normal rotation. Based on the instantaneous rotation speed NES, the rotation trajectory is predicted. This is because the rotational speed of the engine 20 can be calculated more accurately since the engine rotational speed decreases monotonously after the final TDC during normal rotation. That is, before the final top dead center, when the next top dead center is reached, the instantaneous rotational speed NES rises again, resulting in a deviation between the actual rotational speed and the prediction result. On the other hand, since the instantaneous rotational speed NES does not increase after the final top dead center, the actual engine rotational speed and the engine rotational speed can be obtained by using the instantaneous rotational speed NES on the unit waveform TB at the final top dead center. The error from the prediction result is made small.

  In this embodiment, the timing for engaging the pinion 16 with the ring gear 22 is controlled by controlling the timing for pushing the pinion 16 and the timing tp2 for engaging the ring gear 22 with the ring gear 22. That is, it takes time for the pinion 16 to actually engage with the ring gear 22 after the push-out of the pinion 16 is started. Therefore, as shown in FIG. 2, with the timing at which the pinion 16 should be engaged as a reference, the required time from the start of pushing out the pinion 16 to the engagement between the pinion 16 and the ring gear 22 (the pushing operation time TA) is earlier. The extrusion timing tp2 of the pinion 16 is controlled so that the pinion 16 is pushed out.

  FIG. 3 is a flowchart showing a processing procedure related to the starter driving process during the idle stop control. This process is executed at predetermined intervals by the microcomputer of the ECU 30.

  In FIG. 3, first, in step S10, it is determined whether or not the engine 20 is in inertial rotation by executing the engine automatic stop process. If the engine 20 is in inertial rotation, the process proceeds to step S11, and it is determined whether or not the timing tp2 for starting to push out the pinion 16 has already been calculated. If the extrusion timing tp2 has not been calculated, the process proceeds to step S12, and it is determined whether or not there is a pulse input from the crank angle sensor 23. If there is a pulse input, in step S13, the engine rotational speed (instantaneous rotational speed NES) calculated based on the NE signal from the crank angle sensor 23 is calculated and stored each time, and each pulse is also stored. Remember the width.

  In a succeeding step S14, it is determined whether or not it is a monotone decreasing period TDW. Specifically, it is determined whether or not the engine 20 has passed the final TDC during the forward rotation before the engine 20 shifts from the forward rotation to the reverse rotation. Regarding the determination of the final TDC In the present embodiment, the final TDC is determined when the instantaneous rotational speed NES is equal to or lower than a predetermined determination value (for example, 200 to 300 rpm) and the current value with respect to the previous value of the pulse width is equal to or lower than the predetermined value. To do.

  If it is determined that the final TDC has been passed, the process proceeds to step S15, where a plurality of instantaneous rotational speeds NES stored after the final TDC have passed are read out, and a starting point (for example, read out) is read based on the read instantaneous rotational speeds NES. The required time TP (see FIG. 2) until the pinion 16 and the ring gear 22 are brought into meshing state is calculated from the latest instantaneous rotational speed NES). In subsequent step S16, the extrusion timing tp2 of the pinion 16 is calculated based on the calculated required time TP. Specifically, the time (TP-TA) obtained by subtracting the extrusion operation time TA from the start of the extrusion of the pinion 16 to the engagement of the pinion 16 from the required time TP is calculated, and only the time (TP-TA) is calculated from the starting point. The elapsed time is set as the push-out timing tp2 of the pinion 16.

  In step S17, it is determined whether or not the push-out timing tp2 of the pinion 16 has been reached. When the push-out timing tp2 has been reached, the process proceeds to step S18, where the SL2 drive relay 18 is turned on and energization of the coil 15 is started. . Thereby, the pinion 16 is pushed out toward the ring gear 22, and the pinion 16 and the ring gear 22 are meshed.

  As mentioned above, according to this embodiment explained in full detail, the following outstanding effects are acquired.

  During inertial rotation after automatic engine stop, the engine rotation speed in a region that cannot be calculated from the NE signal is predicted using the calculated value based on the detection signal (NE signal) of the crank angle sensor 23, and the prediction result is within the region. Since the drive of the pinion 16 is controlled so that the engagement between the pinion 16 and the ring gear 22 is performed at a desired engine rotation speed in the above, the engagement between the pinion 16 and the ring gear 22 can be performed at an optimal timing. As a result, the meshing sound at the time of meshing between the pinion 16 and the ring gear 22 can be suppressed.

  Since the rotational trajectory is predicted based on a plurality of instantaneous rotational speeds NES in the period TC in which the instantaneous rotational speed NES tends to decrease, the inclination of the engine rotational speed toward zero speed, that is, the rotational trajectory toward zero speed is predicted. can do.

  When the instantaneous rotational speed NES reaches a period TDW in which the monotonous decrease toward zero speed is reached, the rotational trajectory in the period TDW is predicted using a plurality of instantaneous rotational speeds NES. It is suitable for accurately predicting the rotational trajectory near zero speed. Further, at this time, since the rotational trajectory is predicted using the instantaneous rotational speed NES in the monotonous decrease period TDW or in a period as close as possible, the rotational trajectory prediction system can be improved.

  With an electromagnetic pickup type rotation sensor, a magnetic field change is unlikely to occur in the extremely low rotation speed region, and the engine rotation speed cannot be calculated based on the sensor detection signal. Since the trajectory is predicted, the pinion 16 and the ring gear 22 can be engaged at the optimum timing even in this extremely low rotational speed region.

  Since the timing at which the actual engine rotation speed becomes zero is estimated based on the predicted rotation trajectory and the engagement process of the pinion 16 is performed at or near the estimated timing, the engagement between the pinion 16 and the ring gear 22 is performed. It is significant in suppressing the combination. Further, the above-described meshing can be performed at the timing when the speed becomes zero at first by inertial rotation after the automatic engine stop, and as a result, the pinion and the ring gear can be meshed as early as possible. That is, it is suitable for surely completing the meshing before the next engine restart request.

  Since the push-out timing tp2 of the pinion 16 is determined based on the predicted rotation trajectory and the push-out operation time TA required for the push-out operation of the pinion 16, the pinion 16 and the ring gear 22 are meshed at an appropriate time. Can do.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be implemented as follows, for example.

  ・ By a quadratic function connecting three or more continuous instantaneous rotational speeds NES including the intermediate rotational speed NES at the top dead center, the rotational trajectory of the engine inertia rotation after the timing at which the instantaneous rotational speed NES was obtained The configuration is to be predicted. According to such a configuration, an error from the actual rotational speed NEA can be further reduced in predicting the engine rotational speed.

  -Based on the instantaneous rotational speed NES in two or more unit waveforms TB, it is set as the structure which estimates the rotational trajectory of the engine inertia rotation after the timing when the instantaneous rotational speed NES was obtained. Specifically, for example, the rotational trajectory is predicted based on three or more instantaneous rotational speeds NES in two adjacent unit waveforms TB.

  The rotation trajectory is predicted based on the NE signal immediately before the rotation speed region where the passage of the tooth portion cannot be detected by the rotation sensor (crank angle sensor 23). For example, in an electromagnetic pickup type rotation sensor, a magnetic field change is less likely to occur in an extremely low rotation speed region, and the engine rotation speed may not be calculated using the NE signal. At this time, the prediction accuracy can be improved by predicting the rotation trajectory based on the lowest possible rotation speed. Here, the fact that the passage of the tooth portion cannot be detected by the rotation sensor may be determined, for example, based on whether or not the pulse width is equal to or greater than a predetermined value.

  In the above embodiment, the rotational trajectory of engine inertia rotation is predicted based on the instantaneous rotational speed NES after passing through the final TDC, and the push-out timing tp2 of the pinion 16 is calculated based on the prediction result. In the engine rotation speed region of a predetermined rotation speed (for example, several hundred rpm) or less, the rotation trajectory when the unit waveform TB is monotonously decreased toward zero speed as it is is changed to a plurality of rotation trajectories on each unit waveform TB. A prediction is made for each unit waveform TB based on the instantaneous rotation speed NES, and the push-out timing tp2 of the pinion 16 is calculated based on the prediction result each time. In this configuration, when a new extrusion timing tp2 is calculated based on the instantaneous rotational speed NES in the next unit waveform TB, it is updated each time at the newly calculated timing.

  The rotational trajectory predicted based on the instantaneous rotational speed NES is changed according to the operating state of the engine 20 or an auxiliary machine driven by the engine 20. That is, the degree of decrease (inclination) in the engine rotation speed during inertial rotation of the engine 20 varies depending on the operating state of the engine 20 and the like. Specifically, for example, the lower the temperature information of the engine 20, such as the engine coolant temperature, the engine oil temperature, and the outside air temperature, the greater the friction at the sliding portion between the cylinder and the piston of the engine 20, resulting in the engine speed NE. The degree of decrease is small. In addition, as the compression load of the cylinder increases (for example, as the throttle opening increases), the degree of decrease in the engine rotation speed increases.

  Further, the degree of decrease in the engine rotation speed during inertial rotation of the engine 20 changes according to the driving state of the auxiliary machine driven by the rotation of the crankshaft 21. Specifically, when the in-vehicle air conditioner is provided in the present system, the degree of decrease in the engine rotation speed is greater when the air conditioner is on than when it is off. Therefore, if the change in the engine rotation speed is predicted in consideration of the operating state of the engine 20, the error of the predicted value with respect to the actual value can be further reduced.

  Calculate the gradient (decrease degree) of the engine rotation speed in the monotonic decrease period TDW and the time required to reach the monotonic decrease period TDW during inertial rotation of the engine 20, and calculate from the NE signal based on the calculation result The configuration is such that the rotation trajectory of the rotation speed region where it cannot be predicted. Specifically, for example, the instantaneous rotational speed NES in the unit waveform TB before the final TDC is used, and based on the instantaneous rotational speed NES, the linear waveform or the quadratic function is used to decrease the unit waveform TB. Is calculated. Further, a required time (offset amount) corresponding to the instantaneous rotational speed NES at the time of calculating the inclination is calculated. Then, the time at which the predetermined rotational speed is obtained using the above inclination at the time when the unit waveform TB appears is calculated, and the time at which the time is delayed by the offset amount is set as the meshing timing.

  A rotational trajectory predicted based on the instantaneous rotational speed NES during a period in which the engine 20 is inertially rotated after the past automatic engine stop is stored, and the pinion 16 is based on the stored past rotational trajectory. Is configured to control the timing of meshing with the ring gear 22. According to this configuration, it is not necessary to perform the prediction of the rotation trajectory in the engine inertia rotation based on the sensor value every time the engine is automatically stopped. Specifically, based on the instantaneous rotational speed NES at the time of the past automatic engine stop, for example, a rotation trajectory of engine inertia rotation is predicted by a linear function or a quadratic function, and the rotation trajectory (for example, inclination) at that time is stored as a learning value. Keep it. Then, during this inertial rotation, the stored learned value is read out, and the rotational trajectory of engine inertial rotation is predicted using the learned value. The learned value is stored in association with the operation state of the engine 20 at that time and the operation state of the auxiliary machine driven by the engine 20 at a past time point. Then, a learning value corresponding to the current operating state of the engine or the engine-driven auxiliary machine may be read, and the rotation trajectory of the engine rotation speed may be predicted from the read learning value.

  In the above embodiment, the rotation speed of the engine 20 is detected by the crank angle sensor 23. However, the rotation sensor for detecting the rotation of the crankshaft 21 is not limited to this, and is connected to the crankshaft 21, for example. The rotational speed of the engine 20 may be detected by a sensor for detecting the rotational speed of the pulley or a sensor for directly detecting the rotational speed of the ring gear 22. Of these, the rotation sensor of the ring gear 22 has the largest number of teeth provided on the outer peripheral portion of the ring gear 22 and is suitable for more accurately detecting the engine rotation speed.

  DESCRIPTION OF SYMBOLS 10 ... Starter, 11 ... Motor, 13 ... SL1 drive relay, 14 ... Pinion shaft, 15 ... Coil, 16 ... Pinion, 18 ... SL2 drive relay, 20 ... Engine, 21 ... Crankshaft, 22 ... Ring gear, 23 ... Crank angle Sensors 24... Pulser 25. Electromagnetic pickup section 30. ECU ECU SL1 Motor switch section SL2 Actuator

Claims (10)

An automatic stop start function for automatically stopping the engine when a predetermined automatic stop condition is satisfied, and then starting cranking by a starter and restarting the engine when a predetermined restart condition is satisfied; An engine stop / start control device that performs cranking in a state where a pinion of the starter is engaged with a ring gear connected to an output shaft of the engine upon restart, and releases the engagement after the cranking is completed. And
Rotation speed calculation means for calculating an instantaneous rotation speed as the engine rotation speed calculated from a time required for rotation of the output shaft at a predetermined rotation angle based on a detection signal of a rotation sensor that detects rotation of the output shaft. When,
Among the instantaneous rotational speeds calculated by the rotational speed calculation means during the inertial rotation of the engine after the engine is automatically stopped, the instantaneous rotational speed tends to decrease in the unit waveform when the instantaneous rotational speed decreases and increases Predicting means for predicting a rotational trajectory in which the rotational speed of the engine inertial rotation is zero based on a plurality of instantaneous rotational speeds in a period of time ,
Based on the rotation trajectory predicted by the prediction means, a control means for estimating the timing at which the actual engine rotation speed becomes zero and performing the pinion meshing process at or near the estimated timing ;
An engine stop / start control device comprising: 2. The engine stop / start control device according to claim 1, wherein the control means estimates a timing at which the engine rotation speed first becomes zero in inertial rotation after the engine automatic stop. 3. The prediction unit, when the instantaneous rotational speed reaches a monotone decreasing period monotonously decreases toward zero speed, according to claim 1 or 2 for predicting the rotation path based on the plurality of instantaneous rotational speed Engine stop / start control device. The engine stop / start control apparatus according to claim 3, wherein the prediction unit predicts the rotation trajectory by a linear function connecting a plurality of instantaneous rotation speeds immediately after top dead center. The prediction means, an engine stop and start control system according to any one of claims 1 to 4 engine rotational speed of the engine coasting to predict the rotation trajectory when reduced to a predetermined rotational speed. The rotation sensor detects passage of a plurality of teeth provided on a pulser that rotates with the output shaft,
The rotation speed calculation means calculates the engine rotation speed based on a pulse interval of a detection signal output from the rotation sensor according to the passage of the tooth portion,
The engine stop according to any one of claims 1 to 5 , wherein the prediction unit predicts the rotation trajectory based on a sensor detection signal immediately before a rotation speed region where the passage of the tooth portion cannot be detected by the rotation sensor. Start control device. The prediction means calculates, as the rotation trajectory, a slope of a monotonic decrease period in which the instantaneous rotation speed monotonously decreases toward zero speed, and a time required to reach the monotonic decrease period during inertial rotation of the engine. The engine stop / start control device according to claim 1 or 2 .   The said control means determines the operation start timing of the said pinion based on the rotation track | orbit estimated by the said prediction means, and the meshing operation time required for the meshing operation of the said pinion. The engine stop / start control device described in 1. Storage means for storing the rotation trajectory predicted by the prediction means;
The engine stop start control according to any one of claims 1 to 8, wherein the control unit controls a timing at which the pinion meshes with the ring gear based on a past rotation trajectory stored in the storage unit. apparatus.   The said prediction means changes the rotational trajectory estimated based on the engine rotational speed calculated by the said rotational speed calculation means based on the driving | running state of the said engine or the auxiliary machine driven by this engine. The engine stop / start control device according to claim 1.

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