JP2012031820A - Engine stop start control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform engagement of a pinion with a ring gear, by the appropriate timing though it is simple control.SOLUTION: In an ECU 40, an engine 20 is stopped automatically when the prescribed automatic stop condition is satisfied, and after that, when a prescribed restart condition is satisfied, cranking by a starter 10 is started, and the engine 20 is restarted. Also, in the ECU 40, when the restart condition is satisfied in a period in which engine rotation speed is dropped when the engine 20 is stopped automatically, energizing timing of the motor 11 is controlled so that difference of passage speed of each tooth, between the pinion 14 and the ring gear 22, in the engagement point becomes the prescribed value or less before motor rotation speed reaches the maximum rotation speed which can be raised accompanying power supply. Then, the pinion 14 and the ring gear 22 are engaged at timing at which difference of passage speed each tooth becomes the prescribed value or less.

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.

When restarting the engine, from the viewpoint of improving drivability, it is desirable to start the engine as soon as possible after a restart request, and various techniques have been proposed for that purpose (see, for example, Patent Document 1). ). In Patent Document 1, when there is a restart request during a period when the engine rotation speed when the engine is automatically stopped, the engine is stopped using a starter without waiting for the engine rotation to stop completely. It is disclosed to perform ranking. In this Patent Document 1, at the time when a restart request is made (t _{2 in} FIG. 4), the motor is energized at a speed to rotate the pinion, and then, when the rotation speed of the pinion is synchronized with the rotation speed of the ring gear. Engage the pinion with the ring gear. As a result, the engine is returned to the operating state as soon as possible. Further, when the pinion and the ring gear are synchronized with each other, they are engaged with each other so as to suppress the engagement noise and the pinion wear.

Japanese Patent No. 4211208

  However, in Patent Document 1, since the starter is energized at the timing of the restart request, if the engine speed at the time of the restart request is high, the time until the pinion rotation speed and the ring gear rotation speed are synchronized There is a concern that the energization time of the motor becomes longer due to the lengthening. In addition, when the pinion and the ring gear are rotationally synchronized, it is necessary to perform speed control of the motor, which may complicate starter drive control when the engine is restarted.

  The present invention has been made to solve the above-described problems, and provides an engine stop / start control device capable of performing engagement of a pinion and a ring gear at an appropriate timing while being simple control. Main purpose.

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

  The present invention performs cranking using a starter that includes a meshing means for meshing a pinion with a ring gear connected to an output shaft of an engine, and a motor that rotates by supplying power from a power source and applies a rotational force to the pinion. The engine is automatically stopped when a predetermined automatic stop condition is satisfied, and after the automatic stop condition is satisfied, cranking is performed by the starter when a predetermined restart condition is satisfied. The present invention relates to an engine stop / start control device that restarts the engine.

  According to the first aspect of the present invention, when the restart condition is satisfied during a period when the engine rotation speed when the engine is automatically stopped, the teeth of the pinion and the ring gear pass at the meshing point. Motor control means for controlling the energization timing of the motor so that the difference in speed becomes equal to or less than a predetermined value before the motor rotation speed reaches the maximum rotation speed that can be increased with power supply; and the passing speed of each tooth And a meshing control means for meshing the pinion and the ring gear by the meshing means at a timing when the difference between them becomes equal to or less than the predetermined value.

  In short, in the above-described configuration, when the restart condition is satisfied during the engine rotation speed decrease period when the engine is automatically stopped, the rotation increase period before the motor rotation speed reaches the maximum rotation speed that can be increased by the start of energization. Then, the motor energization is started so that the passing speeds of the teeth of the pinion and the ring gear substantially coincide with each other, and the pinion and the ring gear are engaged with each other at the timing when the passing speeds of the respective teeth of the both are substantially the same. According to this configuration, since it is not necessary to provide a period for maintaining the motor rotation speed at the maximum rotation speed after the energization of the motor is started until the passage speeds of the teeth of the pinion and the ring gear substantially coincide with each other. The motor energization time can be suppressed from becoming longer than necessary.

  In addition, the present inventor pays attention to the transition of the motor rotation speed when the motor is energized, and the starter temperature, etc. is higher in the rotation increase period until the motor rotation speed reaches the maximum rotation speed than after reaching the maximum rotation speed. It was found that the variation in the motor rotation speed due to the difference in the motor was small. In other words, according to the present configuration in which meshing is performed before the motor rotation speed reaches the maximum rotation speed, by controlling the motor energization timing, the pinion rotation speed variation due to the difference in the starter state is small. The both can be engaged. Therefore, according to the above configuration, the engagement of the pinion and the ring gear can be performed at an appropriate timing while being relatively simple control.

  Specifically, as in the second aspect of the invention, the timing at which the difference between the passing speeds of the teeth is equal to or less than the predetermined value is calculated based on the time constant of the motor, and based on the calculated timing. Thus, the energization timing may be calculated. In this case, for example, the engagement of the pinion and the ring gear is performed before or after the time corresponding to the time constant + α (for example, α = 10%) has elapsed from the energization timing of the motor. It is preferable to control the energization timing.

  The invention according to claim 3 is provided with a rotation prediction means for predicting the engine rotation speed during the decrease in the engine rotation speed when the engine is automatically stopped, and the predicted rotation predicted by the rotation prediction means. Based on the speed, a timing at which the difference between the passing speeds of the teeth becomes equal to or less than the predetermined value is calculated.

  When the engine rotation speed is decreasing when the engine is automatically stopped, by predicting the engine rotation speed during the decrease, the timing at which the difference in the passing speed of each tooth between the pinion and the ring gear falls below a predetermined value, that is, meshing Timing can be determined accurately. In addition, if the meshing timing can be accurately determined, the motor energization timing can be set to an appropriate timing. As a result, the meshing between the pinion and the ring gear can be performed after the motor energization has started and the maximum rotational speed. Can be done reliably before reaching.

  According to a fourth aspect of the present invention, a cranking rotational speed region is defined as a motor rotational speed range in which power is transmitted from the pinion to the ring gear during the cranking, and the motor rotational speed is determined by the cranking. The energization timing is controlled so that the difference between the passing speeds of the teeth is equal to or less than the predetermined value before exceeding the rotation speed region.

  In the motor, the motor rotational speed and the output torque are in a contradictory relationship, and there is a characteristic that the higher the motor rotational speed, the smaller the torque transmitted from the motor to the pinion (see FIG. 6). On the other hand, at the time of cranking, it is necessary to output a torque sufficient to rotate the engine output shaft from the motor. For example, a rotational speed region (cranking rotational speed region) that is smaller than a rotational speed that can be output in a motor-free state. Therefore, it is necessary to rotate the pinion by driving the motor. Therefore, if meshing is performed at a higher rotational speed than the cranking rotational speed region, sufficient rotational force cannot be applied to the engine output shaft in the high rotational state, and the motor rotational speed is cranked. It is necessary to reduce the rotational speed.

  In that respect, in the above-described configuration, the pinion and the ring gear are engaged before the motor rotation speed exceeds the cranking rotation speed region, so that it is not necessary to reduce the motor rotation speed. Therefore, useless power consumption can be suppressed, and the engine can be started quickly.

1 is an overall schematic configuration diagram of an engine control system. The flowchart which shows the process sequence of starter drive control. The figure which shows the starting characteristic of a motor. The figure which shows the relationship between the rotation raise track | orbit of pinion rotational speed, and meshing timing. The flowchart which shows the process sequence of starter drive control. The figure which shows a motor characteristic. Subroutine for timing setting processing.

  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. 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, a starter 10 is provided with a motor 11, and the motor 11 is rotationally driven by power supply from a battery 12. A pinion shaft 13 is engaged with a rotation shaft (not shown) of the motor 11, and at one end of the pinion shaft 13, the pinion 14 intermittently transmits power between the pinion shaft 13 and the pinion 14. And is supported in one piece.

  The pinion shaft 13 is supported by one end of a lever 17 that rotates about a shaft 16. A first solenoid SL <b> 1 including a coil 18 and a plunger 19 is disposed at the other end of the lever 17, and the plunger 19 disposed in the coil 18 is supported by the lever 17. In the non-energized state of the coil 18, the pinion 14 is disposed in a non-contact state with respect to the ring gear 22 connected to the output shaft (crankshaft) 21 of the engine 20.

  When the coil 18 is energized from the battery 12 in the non-contact state between the pinion 14 and the ring gear 22, the plunger 19 is moved in the axial direction due to the energization, and the lever 17 is rotated around the shaft 16 along with the movement. To do. As a result, the pinion 14 is pushed out in the direction toward the ring gear 22, and the pinion 14 and the ring gear 22 are engaged with each other.

  Further, when the pinion 14 and the ring gear 22 are engaged with each other, the energization of the coil 18 is interrupted, whereby the pinion shaft 13 is displaced in the direction opposite to the direction toward the ring gear 22 by the biasing force of a spring (not shown). Due to the displacement of the pinion shaft 13, the engagement between the pinion 14 and the ring gear 22 is released, and the contact state between the two is released.

  An IG switch 23 is provided between the starter 10 and the battery 12, and the starter 10 can be energized from the battery 12 by turning on the IG switch 23 based on the operation of the driver. In addition, an SL1 drive relay 24 that switches between energization / non-energization of the first solenoid SL1 based on a control signal is provided between the coil 18 and the battery 12, and between the motor 11 and the battery 12, A second solenoid SL2 connected to the electromagnetic element of the motor 11 and switched between energization / non-energization by opening and closing a contact and an SL2 drive relay 25 switching between energization / non-energization of the second solenoid SL2 based on a control signal are provided. Yes.

  In addition, the present system includes a crank angle sensor 31 that outputs a rectangular crank angle signal for every predetermined crank angle of the engine 20 (for example, in a cycle of 30 ° CA), and a cooling water temperature sensor 32 that detects the temperature of engine cooling water. Various sensors such as are provided.

  The ECU 40 is an electronic control device including a known microcomputer or the like, and inputs detection results of various sensors provided in the system, and based on this, fuel injection amount control, ignition timing control, idle stop control Various engine controls such as the above, and drive control of the starter 10 are performed.

  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. Further, the engine restart condition includes, for example, at least one of an accelerator depression operation, a brake operation amount becoming zero, and the like.

  Regarding the drive control of the starter 10, the ECU 40 includes an output port P1 that outputs an on / off signal of the SL1 drive relay 24 and an output port P2 that outputs an on / off signal of the SL2 drive relay 25. The starter 10 can be automatically energized (regardless of the switching state of a starter switch not shown) by the control signals from the output ports P1 and P2. Moreover, the energization states of the motor 11 and the coil 18 can be individually switched by these control signals.

  Further, in the present embodiment, when the engine restart condition is satisfied during the period when the engine rotation speed when the engine 20 is automatically stopped, the pinion 14 is rotated by the motor 11 and the pinion 14 remains in the rotated state. The pinion advance control for engaging the ring gear 22 with the ring gear 22 is performed.

  FIG. 2 is a time chart for explaining the pinion advance control. FIG. 2 shows the transition of the engine rotational speed Ne (pinion rotational speed) after the engine automatic stop condition is satisfied, and the transition of the pinion rotational speed Np when the motor is driven. Of the lines indicating the transition of the engine rotation speed Ne in the figure, the solid line indicates the actual rotation speed, and the broken line indicates the value measured by the crank angle sensor 31. In FIG. 2, the transition of the rotational speed indicates the case where the SL1 drive relay 24 and the SL2 drive relay 25 are in the off state.

  After the combustion is stopped due to the establishment of the automatic engine stop condition, as shown in FIG. 2, the engine rotational speed Ne decreases or increases or decreases as the cylinder volume increases or decreases, or decreases linearly. Eventually it will converge to zero. On the other hand, the pinion rotation speed Np rises rapidly at the beginning of rotation with the start of power supply from the battery 12 to the motor 11 due to the motor characteristics, and the increase speed of the rotation speed decreases with time. It becomes constant at Nmax.

  When the engine restart condition is satisfied during the engine speed reduction period, first, an ON signal is output to the SL2 drive relay 25 at timing t11, and energization of the motor 11 is started. Subsequently, an ON signal is output to the SL1 drive relay 24 at timing t12. As a result, the pinion 14 is pushed out toward the ring gear 22 in a rotated state, and then the tooth portion of the pinion 14 is engaged with the tooth portion of the ring gear 22 at timing t13, so that power can be transmitted from the pinion 14 to the ring gear 22. It becomes a state. The time from timing t12 to t13 corresponds to the time required from the start of pushing out of the pinion 14 until the pinion 14 and the ring gear 22 are engaged (interlocking required time TA).

  In the present embodiment, the energization timing t11 of the motor 11 and the push-out timing t12 of the pinion 14 are estimated based on the prediction data by predicting the engine rotation speed Ne and the pinion rotation speed Np in a period after the current time. Yes. For example, if the timing is point A in FIG. 2, first, the engine rotation descending trajectory and pinion rotation increasing trajectory after point A are predicted. Next, the timing (meshing timing) at which the rotational speed difference between the pinion 14 and the ring gear 22 is equal to or less than a predetermined value is calculated using the predicted data. Then, the timing before the meshing timing (t13) by the required meshing time TA is set as the extrusion timing (t12), and it is necessary for the pinion rotational speed Np to reach the rotational speed at the time of meshing from the meshing timing (t13). The timing just before the time is defined as the energization timing (t11). As a result, the meshing between the pinion rotational speed Np and the ring gear rotational speed Nr is performed at a timing at which they substantially coincide.

  In this specification, for the sake of convenience, the ring gear 22 and the pinion 14 are in a state in which the tooth passing speed provided on the outer peripheral edge of the ring gear 22 and the tooth passing speed provided on the outer peripheral edge of the pinion 14 are not more than a predetermined value. Is expressed as a state in which the difference in rotational speed is less than or equal to a predetermined value (a state that substantially matches). Therefore, for example, when it is expressed that the rotation speed of the ring gear 22 and the rotation speed of the pinion 14 are equal, the passage speed of the teeth provided on the outer peripheral edge of the ring gear 22 and the passage of the teeth provided on the outer peripheral edge of the pinion 14 In this case, the actual rotational speed of the pinion 14 is a rotational speed corresponding to the ratio of the diameter of the ring gear 22 to the diameter of the pinion 14. For example, when it is expressed that the passing speeds of the teeth of the pinion 14 and the ring gear 22 are equal, if the diameter of the ring gear 22 is 10 times the diameter of the pinion 14, the actual rotational speed of the pinion 14 is the actual speed of the ring gear 22. The rotation speed is 10 times the rotation speed.

  As a method for predicting the engine rotational descending trajectory, for example, a method for predicting the engine rotational speed descending trajectory that increases / decreases as the cylinder volume increases / decreases using the engine 20 loss torque (friction torque), engine rotational speed, and inertia as parameters. Is mentioned. Alternatively, the rotational trajectory of the decrease change in the engine rotational speed after the present may be predicted using the past engine rotational speed (instantaneous rotational speed) as a parameter.

As a method for predicting the pinion rotation ascending trajectory, for example, a method using the following formula (1) obtained by modeling the rotation ascending trajectory of the pinion 14 with a first-order lag model of a predetermined time constant τ can be used.
Np = Npmax {1-exp (-t / τ)} (1)
Np represents the pinion rotation speed, Npmax represents the maximum pinion rotation speed, and t represents time.

  Regarding the meshing timing (t13), in this embodiment, the ring gear rotational speed Nr (engine rotational speed) is higher than the pinion rotational speed Np (Nr> Np), and the rotational speed difference between the ring gear rotational speed Nr and the pinion rotational speed Np. Is a timing at which the value becomes less than a predetermined value α (for example, 200 rpm) (Nr−Np <α). When the condition “Nr> Np” is satisfied, the pinion 14 is idled by the one-way clutch 15, so that the rotation of the pinion 14 is not transmitted to the pinion shaft 13. Therefore, when the pinion 14 and the ring gear 22 are meshed with each other, the collision between the teeth of the pinion 14 and the teeth of the ring gear 22 can be suppressed, and accordingly, the meshing noise and the wear of the pinion 14 can be suitably suppressed. It is.

  Next, the energization timing (t11) of the motor 11 will be described in detail.

  In accordance with the switching from off to on of the motor energization, the inventor is in a state where the starter 10 is in a state where the starter 10 is in a rotation increase period until the motor rotation speed reaches the maximum rotation speed than after reaching the maximum rotation speed. We obtained the knowledge that the variation of the motor rotation speed due to the difference of the motor is small.

  FIG. 3 is a diagram illustrating the rising characteristics of the motor 11. In the figure, (a) shows the rising characteristic for each starter temperature, and (b) shows the rising characteristic for each charge amount (SOC) of the battery 12.

  In FIG. 3, the motor rotation speed rises rapidly at the beginning of energization and eventually becomes constant at the maximum rotation speed. At this time, the lower the starter temperature or the lower the SOC, the lower the maximum rotation speed of the motor 11. Further, in the state where the rotation speed has converged, the variation in the motor rotation speed due to the difference in the starter temperature or the SOC is large. Specifically, for example, in the timing ta after the convergence in FIG. Is equal to ΔN1, whereas at the timing tb before convergence, the variation in the motor rotation speed is ΔN2, which is smaller than ΔN1.

  The difference in the motor rotation rising trajectory occurs due to deterioration of the starter 10 in addition to parameters such as the starter temperature and SOC. In this case, as the starter 10 is further deteriorated, the maximum rotation speed of the motor 11 is lowered. As a result, after the motor rotation speed converges, the motor rotation speed due to a difference in the degree of deterioration of the starter compared to before the convergence. The variation of the will become large.

  Such a variation in the motor rotation speed due to the difference in the state of the starter 10 leads to a variation in the pinion rotation speed. Further, if the variation of the pinion rotation speed due to the state of the starter 10 is large, it is considered that the meshing timing (t13) cannot be accurately predicted.

  FIG. 4 shows the relationship between the rotation rising trajectory of the pinion rotational speed Np and the meshing timing. FIG. 4 shows the rising characteristics for each starter temperature. As shown in FIG. 4, the meshing timings tx to tz, that is, the timing at which the pinion rotation speed Np and the ring gear rotation speed Nr substantially coincide with each other depends on the starter temperature due to the difference in the rotation ascending trajectory. The lower the is, the slower the meshing timing is.

  When the meshing timing (t13) cannot be calculated accurately, it is considered that the meshing of the pinion 14 and the ring gear 22 cannot be performed at a timing suitable for meshing. In such a case, there is a concern that the meshing sound between the pinion 14 and the ring gear 22 may increase or an impact due to the meshing may occur. In particular, although the starter temperature can be predicted based on the engine water temperature detected by the cooling water temperature sensor 32, the starter temperature may not be accurately predicted when based on the engine water temperature. In addition, it is conceivable to separately provide a sensor for detecting the starter temperature, but in that case, there are concerns about an increase in the number of parts and an increase in cost. As described above, there is a problem that the variation in the motor start-up characteristic is difficult to be eliminated by the correction by the temperature.

  Further, in the pinion advance control, when the energization timing is too early, for example, when the motor energization is started at the timing when the engine restart condition is satisfied, there is a period in which the motor rotation speed is kept at the maximum reached rotation speed. There is. In such a case, it is considered that the power consumption of the motor 11 becomes larger than necessary.

  Therefore, in this embodiment, when the engine restart condition is satisfied during a period when the engine rotation speed when the engine is automatically stopped, the difference between the passing speeds of the teeth of the pinion 14 and the ring gear 22 is the motor rotation speed. The energization timing of the motor 11 is controlled so as to be equal to or less than a predetermined value before reaching the maximum rotational speed, and the pinion 14 and the ring gear 22 are engaged at a timing when the difference in the passing speed of each tooth is equal to or less than the predetermined value. We are going to carry out matching. In other words, in this control, the on / off switching timing of the motor 11 is controlled and the motor rotation speed is increased accordingly, so that the meshing between the pinion 14 and the ring gear 22 is performed at an appropriate timing. ing.

  FIG. 5 is a flowchart illustrating a processing procedure of starter drive control according to the present embodiment. This process is executed by the ECU 40 at predetermined intervals.

  In FIG. 5, first, in step S11, it is determined whether or not an engine restart condition is satisfied during a period in which the engine speed when the engine 20 is automatically stopped. If the determination is affirmative, the process proceeds to step S12. move on.

  In step S12, the energization timing (t11) of the motor 11 and the push-out timing (t12) of the pinion 14 are set (timing setting process). In the present embodiment, the energization timing and the push-out timing are set based on the meshing timing so that the meshing timing (t13) is the timing before the motor rotational speed Nm reaches the maximum reached rotational speed.

  With regard to the meshing timing, particularly in the present embodiment, the motor rotation for transmitting power from the pinion 14 to the ring gear 22 during the cranking of the engine 20 during the period before the motor rotation speed Nm reaches the maximum rotation speed. It is before the speed range (cranking rotation speed region Ncr) is exceeded. More specifically, the timing is set based on the time constant τ in the process after the start of energization of the motor 11 until reaching the maximum rotation speed. .

  Here, the meshing timing (t13) is set to the timing before reaching the cranking rotation speed for the following reason.

  That is, as shown in FIG. 6, the characteristics of the motor 11 are such that the motor rotation speed and the torque are in conflict with each other. The higher the motor rotation speed, the smaller the transmission torque from the motor 11 to the pinion 14. Further, when the engine 20 is cranked, it is necessary to output a torque sufficient to rotate the crankshaft 21 from the motor 11, so that the rotational speed range (which is smaller than the rotational speed Nmn that can be output in the no-load state of the motor) ( It is necessary to rotate the pinion 14 by driving the motor 11 in the cranking rotation speed region Ncr). Therefore, even if the motor 11 is rotated to a rotational speed higher than the cranking rotational speed region Ncr, sufficient rotational force cannot be applied to the crankshaft 21 in that state, and eventually the motor rotational speed is cranked. This is because it is necessary to reduce the rotational speed.

  FIG. 7 is a subroutine of timing setting processing. In FIG. 7, first, in step S21, prediction data of a descending trajectory of the engine rotational speed and an ascending trajectory of the pinion rotational speed predicted by another routine (not shown) is read. In the subsequent step S22, the meshing rotational speed Neτ is calculated as the engine rotational speed at the meshing timing using the read prediction data of the pinion rotation ascending trajectory. In the present embodiment, a rotational speed smaller than, for example, (63 + α)% of the maximum value of the pinion rotational speed in the prediction data is set as the meshing rotational speed Neτ.

  In step S23, the timing at which the engine rotational speed Ne reaches the meshing rotational speed Neτ (meshing timing) is calculated using the predicted data of the engine rotational descending trajectory. In step S24, the motor 11 is used with reference to the meshing timing. The energization timing (t11) and the push-out timing (t12) of the pinion 14 are calculated. At this time, regarding the motor energization timing, the time calculated based on the time constant τ, more specifically, the time TB required for the pinion rotation speed to increase to the meshing rotation speed Neτ is taken into account, for example, the required time TB Only the timing before the meshing timing is set. Further, the pinion extrusion timing is set to a timing preceding the meshing timing by the meshing required time TA. Then, this process ends.

  Returning to the description of FIG. 5, in step S13, it is determined whether or not the energization timing (t11) of the motor 11 has been reached. If the motor energization timing has been reached, the process proceeds to step S14, and the SL2 drive relay 25 is turned on. And the second solenoid SL2 is switched from the energized off state to the on state. Thereby, the motor 11 is rotated and the pinion 14 is rotated.

  In step S15, it is determined whether or not the push-out timing (t12) of the pinion 14 has been reached. If the pinion push-out timing has been reached, the process proceeds to step S16 where an ON signal is output to the SL1 drive relay 24, and the first solenoid SL1 is switched from energized off to on. The plunger 19 is displaced in accordance with the energization switching, and the pinion shaft 13 is displaced in the direction toward the ring gear 22 while the rotational force is applied by the motor 11 with the displacement of the plunger 19. Thereby, the pinion 14 is meshed with the ring gear 22 and cranking of the engine 20 is started.

  In step S17, it is determined whether or not the engine rotational speed Ne is equal to or higher than the starting rotational speed Nef (for example, 400 to 500 rpm). This starting rotational speed Nef is set to a value higher by a predetermined speed than the cranking rotational speed. Then, the process proceeds to step S18 on condition that the engine rotational speed is equal to or higher than the starting rotational speed Nef, and an off signal is output to the SL1 drive relay 24 and the SL2 drive relay 25. Thereby, the meshing of the pinion 14 and the ring gear 22 is released, and the rotation of the motor 11 is stopped.

  According to the embodiment described in detail above, the following excellent effects can be obtained.

  If the engine restart condition is satisfied during the period when the engine speed decreases when the engine is automatically stopped, the difference in the passing speed of each tooth between the pinion 14 and the ring gear 22 causes the motor rotation speed to reach the maximum rotation speed. Since the configuration is such that the energization timing of the motor 11 is controlled so as to be equal to or less than a predetermined value before the operation, the meshing of both can be performed in a region where the variation in the pinion rotation speed due to the difference in the state of the starter 10 is small. . In addition, since the on / off switching timing of the motor 11 is controlled and the motor rotational speed is increased in an orderly manner, according to this configuration, the meshing of the pinion 14 and the ring gear 22 can be performed with relatively simple control. It can be implemented at an appropriate timing.

  Moreover, since it is not necessary to provide a period for holding the motor rotation speed at the maximum reached rotation speed, it is possible to prevent the motor energization time from becoming longer than necessary.

  Since the timing at which the difference between the passing speeds of the teeth of the pinion 14 and the ring gear 22 is equal to or less than a predetermined value is calculated based on the time constant τ of the motor 11, the pinion rotation speed due to the difference in the state of the starter 10 The meshing of the two can be performed in a region where the variation of the two is smaller.

  During the engine speed decrease period, the engine speed during the decrease is predicted, and the timing at which the difference between the passing speeds of the teeth of the pinion 14 and the ring gear 22 is equal to or less than a predetermined value is calculated based on the predicted data. Since the configuration is adopted, it is possible to accurately determine the optimum timing for the engagement between the pinion 14 and the ring gear 22. In addition, by accurately determining the meshing timing, the energization timing of the motor 11 can be set to an appropriate timing. As a result, the meshing of the pinion 14 and the ring gear 22 is performed after the energization of the motor 11 is started. This can be done reliably before the maximum rotational speed is reached.

  Since the engagement between the pinion 14 and the ring gear 22 is performed before the motor rotation speed exceeds the cranking rotation speed region Ncr, it is necessary to reduce the motor rotation speed before the engagement between the pinion 14 and the ring gear 22 is performed. There is no. Therefore, useless power consumption can be suppressed, and the engine can be started quickly.

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

  The meshing timing of the pinion 14 and the ring gear 22 may be before the motor rotational speed reaches the maximum rotational speed. For example, when the engine 20 is cranked, power is transmitted from the pinion 14 to the ring gear 22. The timing after reaching the rotation speed (cranking rotation speed) may be used. Further, the timing after the motor energization timing exceeds the time constant τ from the energization timing of the motor 11 may be set as the meshing timing.

  In the above embodiment, the case where the starter 10 having the SL1 drive relay 24 that controls energization / non-energization of the coil 18 and the SL2 drive relay 25 that controls energization / non-energization of the motor 11 is applied to the present invention will be described. However, any starter that can independently control the meshing release of the pinion 14 and the ring gear 22 and the rotation stop of the motor 11 may be used. For example, a conventional starter provided with a relay for controlling motor energization is used. You may apply to invention. That is, in this configuration, instead of the second solenoid SL2 in the starter 10 of FIG. 1, the plunger 19 is provided with a contact for energizing the motor at the end opposite to the lever 17. In this configuration, a motor energization control relay that can be switched on / off based on a control signal from the ECU 40 is provided between the motor 11 and the battery 12. Also in this configuration, the meshing operation of the pinion 14 and the ring gear 22 and the rotation operation of the motor 11 can be independently controlled by individually controlling the SL1 drive relay 24 and the motor energization control relay. .

  DESCRIPTION OF SYMBOLS 10 ... Starter, 11 ... Motor, 14 ... Pinion, 18 ... Coil (meshing means), 20 ... Engine, 21 ... Crankshaft, 22 ... Ring gear, 24 ... SL1 drive relay, 25 ... SL2 drive relay, 40 ... ECU (motor) Control means, engagement control means, rotation prediction means), SL1... First solenoid (engagement means), SL2.

Claims (4)

An engine in which cranking is performed using a starter that includes a meshing means for meshing a pinion with a ring gear connected to an output shaft of the engine, and a motor that rotates by supplying power from a power source and applies a rotational force to the pinion. Applied,
The engine is automatically stopped when a predetermined automatic stop condition is satisfied, and after the automatic stop condition is satisfied, when the predetermined restart condition is satisfied, cranking is performed by the starter to restart the engine. In the engine stop / start control device,
When the restart condition is satisfied during a period in which the engine rotation speed when the engine is automatically stopped decreases, the difference in the passing speed of each tooth between the pinion and the ring gear at the meshing point is the motor rotation speed. Motor control means for controlling energization timing of the motor so as to be equal to or less than a predetermined value before reaching the maximum rotation speed that can be increased with power supply;
Meshing control means for meshing the pinion and the ring gear by the meshing means at a timing when the difference between the passing speeds of the teeth becomes equal to or less than the predetermined value;
An engine stop / start control device comprising:   The motor control means calculates a timing at which a difference between the passing speeds of the teeth becomes equal to or less than the predetermined value based on a time constant of the motor, and calculates the energization timing based on the calculated timing. The engine stop / start control device described in 1. A rotation prediction means for predicting the engine rotation speed during the descent of the engine rotation speed when the engine is automatically stopped;
3. The engine stop / start control device according to claim 2, wherein the motor control unit calculates a timing at which a difference between the passing speeds of the teeth becomes equal to or less than the predetermined value based on the predicted rotation speed predicted by the rotation prediction unit. . A cranking rotational speed region is defined as a motor rotational speed range for performing power transmission from the pinion to the ring gear during the cranking,
The said motor control means controls the said electricity supply timing so that the difference of the passing speed of each said tooth may become below the said predetermined value, before a motor rotational speed exceeds the said cranking rotational speed area | region. The engine stop / start control device according to claim 1.

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