JP5240262B2 - Engine automatic stop / start control device - Google Patents

Description

  The present invention includes a motor that rotationally drives a pinion, and an actuator that pushes the pinion toward the ring gear so that the pinion contacts and meshes with a ring gear coupled to an output shaft of the engine. The engine is automatically stopped when a predetermined stop condition is satisfied, and then the engine is restarted by cranking with the starter when a predetermined restart condition is satisfied. The present invention relates to an engine automatic stop / start control device.

  As this type of control device, as can be seen in Patent Document 1 below, the engine restart condition is reduced during a period (rotation speed reduction period) in which the engine rotation speed (ring gear rotation speed) after the automatic stop of the engine decreases. If established, the initial rotation is applied to the output shaft of the engine by the process of pushing the pinion in a rotationally driven state and bringing it into contact with the ring gear (hereinafter referred to as the motor front drive process) without waiting for the output shaft to stop rotating. (Cranking) is known. Specifically, when the restart condition is satisfied, the pinion is rotationally driven, the timing at which the difference between the ring gear rotational speed and the pinion rotational speed is within a predetermined range is calculated, and the pinion is pushed and rotated based on the calculated timing. To do. As a result, the pinion can be meshed with the ring gear as quickly and smoothly as possible, and the engine can be restarted quickly while suppressing the generation of noise during meshing.

Japanese Patent Laying-Open No. 2005-330813

  By the way, the actual engine rotation speed is higher than originally assumed due to the torque of the on-vehicle auxiliary machine changing or the braking force being applied by the driver's brake operation during the above-mentioned rotation speed reduction period. May decrease. In this case, if the pinion is pushed out at the initially calculated pinion push-out timing, the difference between the ring gear rotation speed and the pinion rotation speed at the time of meshing is not appropriate, and the pinion can be properly meshed with the ring gear. There is a risk that it will not be possible.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an automatic stop / start control device for an engine capable of appropriately engaging a pinion with a ring gear.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  The invention according to claim 1 includes a motor that rotationally drives the pinion and an actuator that pushes the pinion toward the ring gear so that the pinion contacts and meshes with a ring gear connected to the output shaft of the engine. The engine is applied to a vehicle having a starter configured as described above, and the engine is automatically stopped when a predetermined stop condition is satisfied, and then cranked by the starter when a predetermined restart condition is satisfied. In the engine automatic stop / start control device for restarting the engine, prediction means for updating the predicted decrease trajectory at a predetermined cycle while predicting the decrease trajectory of the engine rotation speed after the automatic stop of the engine, and the engine speed The pinion to perform the cranking in a situation where the engine reaches a predetermined high rotation range. In order to perform the cranking under the situation where the motor driving means for operating the motor and the actuator so as to be driven to rotate before being brought into contact with the ring gear, and the engine rotational speed is in a predetermined low rotational range. Post-motor drive means for operating the motor and the actuator so that the pinion is rotated after being brought into contact with the ring gear, and a decrease predicted each time by the prediction means when the restart condition is satisfied Based on the trajectory, a selection unit that selects which of the motor front driving unit and the motor rear driving unit to use the operation processing, and before the pinion is rotationally driven by the motor front driving unit and before being pushed out. The operation process by the motor post drive means by the selection means during the period until If selected, characterized in that it comprises a control means for pushing the pinion at the selected timing.

  In the above invention, the motor and actuator operation processing (hereinafter referred to as “motor front drive processing”) by the motor front drive means and the above operation processing (hereinafter referred to as “motor back drive means”) based on the engine rotation speed decrease trajectory predicted by the prediction means. The post-motor drive processing) is selected. After the motor-first drive process is selected and the pinion is driven to rotate, the torque has been updated due to a change in the torque of the in-vehicle auxiliary equipment or the application of braking force by the driver's brake operation. The predicted value of the engine rotation speed decrease trajectory may be lower than the initial predicted value of the decrease trajectory. Under such circumstances, the post-motor drive process may be selected after the pinion is rotationally driven based on the initially predicted lowering trajectory and before being pushed out. In this case, if the pinion is pushed out at the initial pinion push-out timing by the motor tip drive process, the timing at which the pinion is engaged with the ring gear may be delayed. In this case, the difference in rotational speed between the pinion and the ring gear at the time of meshing may not be appropriate, and the pinion may not be properly meshed with the ring gear.

  In this regard, in the above-described invention, when the post-motor drive process is selected during the period from when the pinion is rotationally driven by the motor-first drive process to before being pushed out, the pinion is pushed out at the timing when the post-motor drive process is selected. Thereby, the delay of the timing which meshes | pinches a pinion with a ring gear can be avoided, and by extension, a pinion can be mesh | engaged appropriately with a ring gear.

  According to a second aspect of the present invention, in the first aspect of the invention, the vehicle has a switch operated by the motor front drive means and the motor post drive means to switch between energization of the motor or stop of energization. And further includes a restricting means for restricting the operation of the switch so that the opening / closing interval of the switch is equal to or longer than a specified time, and the specified time contacts the ring gear after the pinion is pushed out The control means performs the operation process by the motor post drive means by the selection means during a period from when the pinion is rotationally driven by the motor front drive means to before being pushed out. If selected, the rotation drive of the pinion by the motor tip drive means is continued.

  In the above invention, in order to avoid the occurrence of a situation in which the contact of the switch is welded due to the short switching interval of the switch (relay), the switching interval is equal to or longer than a specified time (for example, 100 msec). So that the operation of the switch is limited. Here, when the post-motor drive process is selected in the period from when the pinion is rotationally driven by the motor-first drive process to before being pushed out, for example, the pinion rotational drive is performed at the pinion rotational drive start timing according to the motor post-drive process. It is conceivable that the difference in rotational speed at the time of meshing between the pinion and the ring gear is made appropriate by operating the switch so that the energization to the motor is temporarily stopped and then energized again. . However, since the time (for example, 40 msec) required from when the pinion is pushed out until it contacts the ring gear is shorter than the specified time, the rotation time of the pinion according to the post-motor drive process is set, for example, When energization of the motor is stopped at the push timing, the timing of resuming energization of the motor may be later than the timing when the pinion contacts the ring gear. In this case, the start of cranking may be delayed, and the completion of engine restart may be delayed.

  In this regard, in the above-described invention, when the post-motor drive process is selected during the period from when the pinion is rotationally driven by the motor front drive process to before being pushed out, the rotation of the pinion by the motor front drive process is continued. Thereby, the delay of the rotation drive start timing of the pinion can be avoided, and consequently the delay of completion of the restart of the engine can be avoided.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the post-motor drive means sets the push-out timing of the pinion as a timing when the restart condition is satisfied, and the rotational drive start timing of the pinion Is set as a timing delayed by a predetermined time from the push-out timing, and the motor front drive means sets the push-out timing of the pinion as a timing when the restart condition is satisfied, and The rotary drive start timing is provided with setting means for setting the timing as the timing after the push timing and before the timing delayed by the predetermined time from the push timing, and the control means includes the setting Rotation drive after the pinion is pushed out by means If the operation processing by the motor after the driving means by said selection means in the period leading up to before is selected, characterized in that to continue the extrusion of the pinion by the motor target drive means.

  In the above invention, the pinion push-out timing and the rotational drive start timing by the post-motor drive process and the motor tip drive process are set in the above-described manner. Here, the push-out timing of the pinion is the same at the time when the restart condition is satisfied in both the processing by the setting means included in the motor front drive processing and the motor post drive processing. For this reason, due to the update of the predicted value of the decrease trajectory of the engine rotation speed, the motor is driven during the period from when the pinion is pushed out by the motor drive process until before a predetermined time elapses (before the pinion is rotationally driven). When the driving process is selected, it is considered appropriate to adopt the timing set by the setting means, which is the same timing as the timing set by the post-motor driving process, as the pinion push-out timing. That is, it is considered appropriate to continue pushing out the pinion even when the post-motor driving process is selected.

  In view of this point, in the above invention, when the post-motor driving process is selected during the period from when the pinion is pushed out by the motor leading drive process to before being driven to rotate, the pinion pushing by the motor leading drive process is continued. . As a result, the pinion can be appropriately meshed with the ring gear.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the control unit is configured to perform the motor post-driving unit by the selection unit during a period from when the pinion is pushed out by the setting unit to before being rotationally driven. When the operation process by is selected, the rotational drive start timing of the pinion is reset based on the lowered trajectory updated by the prediction means.

  In the above invention, when the post-motor drive process is selected during the period from when the pinion is pushed out by the setting means to before being driven to rotate, the rotation drive start timing of the pinion is reset in the above manner. Thereby, the difference between the pinion rotation speed and the ring gear rotation speed at the time of meshing of the pinion and the ring gear can be made appropriate.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the selection unit is configured such that the pinion contacts the ring gear based on a lowered trajectory predicted each time by the prediction unit. It is characterized in that it is selected which of the operation processes is adopted so that the difference between the rotation speed of the pinion and the rotation speed of the ring gear at a timing to be less than a specified value.

  In the said invention, in order to suppress appropriately generation | occurrence | production of the noise etc. at the time of meshing | engagement of a pinion and a ring gear, it is selected which of a motor front drive process and a motor post drive process is employ | adopted in the said aspect. For this reason, if the predicted value of the decrease trajectory of the engine rotation speed becomes lower than originally predicted due to the update, the pinion rotation speed at the timing when the pinion contacts the ring gear is appropriate for making the pinion rotation speed equal to or less than the above specified value. The post-motor drive process is likely to be selected before the motor-first drive process is completed. For this reason, the said invention has a big merit provided with the said control means.

The system block diagram concerning one Embodiment. The figure which shows the outline | summary of the prediction method of the engine rotational speed fall trajectory concerning one Embodiment. The figure which shows the outline | summary of the motor front drive process and motor post drive process concerning one Embodiment. The flowchart which shows the procedure of the special case drive process of the starter concerning one Embodiment. The time chart which shows an example of the special drive process of the starter concerning one Embodiment.

  Hereinafter, an embodiment in which a control device according to the present invention is applied to an in-vehicle engine system including a four-stroke four-cylinder engine will be described with reference to the drawings.

  FIG. 1 shows a system configuration diagram according to the present embodiment.

  As shown in the figure, the starter 10 includes a motor 12, a pinion 14 that is rotationally driven by the motor 12, and an electromagnetically driven actuator 16 (hereinafter, actuator SL 1) for pushing out the pinion 14. Each of the rotational drive operation and the push-out operation of the pinion 14 can be executed individually. Specifically, the motor 12 is rotationally driven using a battery 18 as a power supply source, and a switch 20 (hereinafter referred to as a motor) that switches between energization of the motor 12 or stop of energization between the motor 12 and the battery 18. A switch SL2) is provided. The motor switch SL2 is connected to an SL2 drive relay 22 that switches on / off of the switch.

  A pinion shaft 24 that is rotationally driven by energization of the motor 12 is connected to the motor 12, and the pinion 14 is supported at one end of the pinion shaft 24 via a one-way clutch 26. Specifically, when the motor switch SL2 is turned on when the SL2 drive relay 22 is turned on and the motor 12 is energized from the battery 18, the pinion 14 is rotationally driven along with the rotational drive of the pinion shaft 24. The one-way clutch 26 transmits power from the pinion shaft 24 to the pinion 14 as long as the rotation speed of the pinion 14 does not exceed the rotation speed of the pinion shaft 24.

  The other end of the pinion shaft 24 is supported by one end of a lever 32 that rotates about the shaft 30. A force from the actuator SL1 acts on the other end of the lever 32. Specifically, the actuator SL1 includes a coil 34, a plunger 36 disposed in the coil 34 and supported by the lever 32, a return spring 38, and the like, and is driven using the battery 18 as a power supply source. . Between the coil 34 and the battery 18, an SL1 drive relay 40 that switches between energization of the coil 34 or stop of energization is provided.

  In such a configuration, the pinion 14 is in a non-contact state with respect to the ring gear 46 mechanically connected to the output shaft (crankshaft 44) of the engine 42 when the SL1 drive relay 40 is turned off and the coil 34 is not energized. Will be placed. Under such circumstances, when the SL1 drive relay 40 is turned on and the coil 34 is energized, the attractive force of the coil 34 acts on the plunger 36. When the suction force acting on the plunger 36 overcomes the urging force of the return spring 38 acting on the plunger 36, the plunger 36 is displaced in the axial direction. As a result, the lever 32 rotates about the shaft 30, so that the pinion shaft 24 is pushed out toward the ring gear 46, and the pinion 14 comes into contact with and meshes with the ring gear 46. After that, when the SL1 drive relay 40 is turned off and the energization from the battery 18 to the coil 34 is interrupted, the attraction force of the coil 34 is lost, and the plunger 36 is moved by the urging force of the return spring 38 acting on the plunger 36. Displacement in the axial direction. As a result, the pinion shaft 24 is displaced in the direction opposite to the direction toward the ring gear 46, and the meshing between the pinion 14 and the ring gear 46 is released.

  The engine 42 is provided with an electromagnetically driven fuel injection valve 48 that supplies fuel to the combustion chamber of the engine 42. A crank angle sensor 50 that detects the rotation angle of the crankshaft 44 is provided near the crankshaft 44 of the engine 42. The crank angle sensor 50 generates a rectangular crank signal when a plurality of protrusions provided at equal intervals (for example, every 30 ° CA) cross the sensor on the outer periphery of a rotor (not shown) that rotates integrally with the crankshaft 44. Output.

  An electronic control device (hereinafter referred to as ECU 52) whose operation target is an engine system is mainly composed of a microcomputer composed of a well-known CPU, ROM, RAM and the like. The ECU 52 receives an output signal from the crank angle sensor 50 and the like. The ECU 52 executes various control programs stored in the ROM in response to the input, thereby performing fuel injection control by the fuel injection valve 48, idle stop control, drive control of the starter 10, and the like.

  In the idle stop control, when the predetermined stop condition is satisfied, the engine 42 is automatically stopped by stopping the fuel injection from the fuel injection valve 48, and then the starter 10 is driven when the predetermined restart condition is satisfied. The engine 42 is restarted by the control and the start of fuel injection from the fuel injection valve 48 or the like. The stop condition is true, for example, that the logical product of the condition that the brake operation is performed and the condition that the vehicle traveling speed is equal to or lower than a predetermined speed (0 or a predetermined speed higher than 0) is true It may be a condition. The restart condition includes, for example, a condition that the brake operation is released and a condition that there is a drive request for an unillustrated engine-driven in-vehicle auxiliary machine (for example, the amount of power stored in the battery 18 becomes less than a predetermined value and the in-vehicle power generation The condition that the logical sum is true, such as the condition that there is a machine drive request, may be used.

  In the drive control process of the starter 10, the initial rotation is applied to the crankshaft 44 by rotating the pinion 14 in a state where the pinion 14 and the ring gear 46 are engaged by energizing the SL1 drive relay 40 and the SL2 drive relay 22. To perform (cranking). In this embodiment, the ON / OFF interval of the relays is set to avoid the situation where the contacts of the SL1 drive relay 40 and the SL2 drive relay 22 are welded due to a short time. On / off restriction processing is performed to limit the operation of these relays so that the time limit (for example, 100 msec) is exceeded.

Although it is desirable that the engine 42 is restarted as soon as possible when the restart condition is satisfied, when the pinion 14 is brought into contact with the ring gear 46 in a state where the ring gear rotation speed (engine rotation speed) is high, The sound generated when the pinion 14 and the ring gear 46 are engaged with each other increases, which may cause driver discomfort. For this reason, in this embodiment, when the restart condition of the engine 42 is satisfied during a period in which the engine rotation speed decreases after the engine 42 is automatically stopped (rotation speed decrease period), the engine in the period is used as the drive control. By selecting which of the motor front drive processing and the motor post drive processing is to be adopted based on the predicted value of the rotation speed decrease trajectory, the engine 42 is restarted quickly, and the pinion 14, the ring gear 46, To reduce the noise generated during the engagement. Hereinafter, after describing the process of predicting the decrease in the engine rotation speed, the motor front drive process and the motor post drive process will be described.
<1. Prediction process for engine speed reduction trajectory>
First, the engine rotation speed decrease trajectory prediction process will be described with reference to FIG.

  In this embodiment, the loss torque, which is the amount of change in the rotational energy of the crankshaft 44 per specified period (crank signal input cycle, 30 ° C. A), the rotational angular velocity (hereinafter referred to as angular velocity) of the crankshaft 44, and the inertia of the engine 42 Based on the prediction result, the angular velocity at the next calculation timing is predicted at a predetermined calculation cycle (crank signal output cycle), and the angular velocity at the next calculation timing is further predicted based on the prediction result. Predict the engine rotation speed decrease trajectory during the speed decrease period. Specifically, based on the instantaneous rotational speed in the rotational pulsation period prior to the present time, with one period (for example, 180 ° C. A) of increase / decrease in engine rotational speed (instantaneous rotational speed) accompanying each increase / decrease in cylinder volume as a rotational pulsation period. The engine rotational speed in the rotational pulsation period after the current time is predicted. In this prediction method, the actual engine rotation speed decrease trajectory during the rotation speed decrease period is accompanied by pulsation as shown by the solid line in the figure due to the pumping loss due to the change in the cylinder volume. In view of the above.

  The process of predicting the lowered trajectory will be specifically described with reference to FIG. In this embodiment, the rotation pulsation period is a 180 ° C. A section from the top dead center (TDC) of each cylinder to the next TDC, and the current rotation pulsation period is indicated by S [i] in FIG. . The current crank angle is assumed to be 30 ° C. after TDC.

  First, during the rotational speed reduction period, the angular speed ω [rad / sec] as the instantaneous rotational speed is calculated by the following equation (1) for each input period (every 30 ° C. A) of the crank signal from the crank angle sensor 50; The calculated angular velocity ω is stored each time.

ω = 30 × 2π / (360 × tp) (1)
Note that tp [sec] indicates a time (pulse width) from the previous rising timing of the crank signal pulse to the rising timing of the current crank signal pulse.

  According to the above equation (1), the angular velocity ω for each crank angle based on the TDC in the previous 180 ° C. A section S [i−1] is calculated and stored. In the present embodiment, the angular velocity ω [0, i-1] at the crank angle 0 ° C. A and the angular velocity ω [30, i − at the crank angle 30 ° A after the TDC in the previous 180 ° A section S [i−1]. 1], angular velocity ω [60, i-1] at a crank angle of 60 ° C, angular velocity ω [90, i-1] at a crank angle of 90 ° A, angular velocity ω [120, i-1] at a crank angle of 120 ° C The angular velocity ω [150, i-1] at a crank angle of 150 ° C. and the angular velocity ω [0, i] at a crank angle of 0 ° A after TDC in the current 180 ° A section S [i] are calculated. Remember.

  Then, based on these calculated angular velocities ω, a loss torque T [N · m] for each predetermined crank angle interval in the previous 180 ° C. A section S [i−1] is calculated. In the present embodiment, the loss torque T [0-30, i-1] from the crank angle 0 ° C to 30 ° C after the TDC in the previous 180 ° C A section S [i-1], from the crank angle 30 ° A Loss torque T [30-60, i-1] up to 60 ° C A, Loss torque T [60-90, i-1] from crank angle 60 ° A to 90 ° A, crank angle 90 ° A to 120 ° A Loss torque T [90-120, i-1], crank torque 120 ° A to 150 ° A, loss torque T [120-150, i-1], and crank angle 150 ° A to 180 ° A The loss torque T [150-0, i-1] up to 0 ° C. after TDC in S [i] is calculated by the following equations (2) to (7).

T [0-30, i-1] = − J × (ω [30, i-1] ^ 2−ω [0, i-1] ^ 2) / 2 (2)
T [30-60, i-1] = − J × (ω [60, i-1] ^ 2−ω [30, i-1] ^ 2) / 2 (3)
T [60-90, i-1] = − J × (ω [90, i-1] ^ 2−ω [60, i-1] ^ 2) / 2 (4)
T [90-120, i-1] = − J × (ω [120, i-1] ^ 2−ω [90, i-1] ^ 2) / 2 (5)
T [120-150, i-1] = − J × (ω [150, i-1] ^ 2−ω [120, i-1] ^ 2) / 2 (6)
T [150-0, i-1] = − J × (ω [0, i] ^ 2−ω [150, i-1] ^ 2) / 2 (7)
J [kg · m ^ 2] is an inertia of the engine 42 and is a value determined in advance based on design data of the engine 42 and the like, and is stored in advance in a ROM or the like of the ECU 52. Each of the calculated loss torques T [0-30, i-1] to T [150-0, i-1] is updated and stored in a register of the ECU 52.

  Subsequently, the angular velocity ω [30, i] at the present time (30 ° C. after TDC in the current 180 ° C. section S [i]) is calculated by the above equation (1), and the calculated angular velocity ω is used. The loss torque T [0-30, i] is calculated. Then, the calculated loss torque T [0-30, i] is updated and stored in a register.

  After that, the loss torque T [30-60, i-1] from the crank angle 30 ° C. to the crank angle 60 ° A in the previous 180 ° A section S [i-1] and the current angular velocity ω [30, i] Based on the above, the predicted value ω ′ [60, i] of the angular velocity at the rising timing of the next pulse (crank angle 60 ° C. after TDC of the current 180 ° C. A section S [i]) is calculated. Based on the calculated angular velocity predicted value ω ′ [60, i], a predicted arrival time t [30-60, i] until the crank angle reaches 30 ° C. from 60 ° C. is calculated. Furthermore, the loss torque T [60-90, i-1] from the crank angle 60 ° C. to 90 ° C. A in the previous 180 ° C. section S [i-1] and the predicted angular velocity ω ′ [60, i] Based on the above, the predicted angular speed ω ′ [90, i] of the crank angle 90 ° C. after TDC in the current 180 ° C. section S [i] is calculated, and the crank angle is changed from 60 ° A to 90 ° C. The predicted arrival time t [60-90, i] until reaching is calculated. By repeatedly calculating the predicted value of the angular velocity and the estimated arrival time for each crank angle in this way, it is possible to predict the trajectory of the engine rotational speed during the rotational speed decreasing period as shown by the broken line in the figure. Become.

Note that the prediction calculation by the above-described lowering trajectory prediction process is executed by using the time until the next crank signal is input at every input cycle of the crank signal (every 30 ° C. A), and the next crank signal is input. In such a case, the prediction calculation is interrupted and the process proceeds to a new prediction calculation using the actual angular velocity calculated based on the next crank angle signal. That is, the engine rotation speed decrease trajectory is updated at every crank signal input cycle (every tp).
<2. Motor first drive processing>
Next, the motor tip drive process will be described with reference to FIG. In the figure, the predicted engine rotation speed decrease trajectory (broken line) is actually accompanied by pulsation but is omitted. The engine rotation speed NE and the pinion rotation speed Np are respectively the ring gear peripheral speed that is the peripheral speed of the tooth portion provided on the outer peripheral edge of the ring gear 46, and the tooth peripheral portion provided on the outer peripheral edge of the pinion 14. The pinion peripheral speed which is speed is shown.

  This process is a process of operating the motor 12 and the actuator SL1 so that the pinion 14 is rotationally driven before being brought into contact with the ring gear 46 and the pinion 14 is engaged with the ring gear 46 in order to perform cranking. According to this process, after the restart condition is established, the pinion 14 is engaged with the ring gear 46 as soon as possible to start cranking, and the generated sound at the time of engagement can be reduced.

  Specifically, first, as shown in the figure, the timing ta at which the engine rotation speed reaches the contact permission rotation speed Ne1 is calculated each time based on the predicted value of the engine rotation speed decrease trajectory after the current time in the rotation speed decrease period. To do. Here, the contact-permitted rotational speed Ne1 is an allowable level of the sound generated when the difference between the pinion rotational speed and the ring gear rotational speed at the timing when the pinion 14 contacts the ring gear 46 in a state where the rotation of the pinion 14 is stopped. The rotation speed can be set to the following (for example, 100 rpm), more specifically, the rotation speed is set such that the difference between the ring gear peripheral speed and the pinion peripheral speed (relative rotational speed difference) is equal to or less than a specified value ΔN. The Then, a timing that is a time required for the pinion 14 to come into contact with the ring gear 46 from the time when the pinion 14 starts to be pushed by a required contact time Tα (for example, 40 msec) is set to the reference timing tb. As each time. When it is determined that the restart condition is satisfied before the calculated reference timing tb, the motor front drive process is performed.

  The push-out timing and the rotational drive start timing of the pinion 14 by the motor-first driving process are the predicted value of the decrease trajectory of the engine rotational speed, the predicted value of the upward trajectory of the pinion rotational speed after the rotational drive of the pinion 14 is started, and the contact It is calculated based on the required time Tα. Here, in the present embodiment, the ascending trajectory of the pinion rotation speed is predicted using a first-order lag model expressed by the following equation (8).

Np = Npmax × {1−exp (−t / τ)} (8)
In the above equation (8), Np [rpm] indicates the pinion rotation speed, Npmax [rpm] indicates the maximum value of the pinion rotation speed, τ indicates a predetermined time constant, and t [sec] Indicates the elapsed time from the start of rotation of the pinion 14.

  The required contact time Tα is shorter than the time required from the start of rotational driving of the pinion 14 until the rotational speed of the pinion 14 reaches its maximum value. For this reason, the rotation of the pinion 14 is performed after the pinion 14 is rotated and then pushed out (motor front drive processing A), and the rotation of the pinion 14 during the period from when the pinion 14 is pushed out to before contacting the ring gear 46. Any one of the processes for starting driving (motor-first driving process B) is selectively performed depending on the situation.

  In other words, in the motor tip drive process A, the pinion rotation speed at the timing when the required contact time Tα elapses from the rotation drive start timing of the pinion 14 is the optimum rotation speed of the pinion 14 at the timing when the pinion 14 contacts the ring gear 46 ( This process is performed when it is predicted that the pinion rotation speed at which the relative rotation speed difference is equal to or less than the specified value ΔN will not be reached. In the present embodiment, the rotation drive start timing of the pinion 14 is set as the restart condition establishment timing (time t1), and the push-out timing of the pinion 14 is set as a timing (time t2) later than the rotation drive start timing. (Refer to the solid line in the figure).

On the other hand, in the motor front drive process B, the pinion rotation speed at the timing when the required contact time Tα elapses from the start of the rotation drive of the pinion 14 is equal to or higher than the optimum rotation speed of the pinion 14 at the timing when the pinion 14 contacts the ring gear 46. This process is performed when it is predicted that In the present embodiment, the push-out timing of the pinion 14 is set as the restart condition establishment timing (time t3), and the rotational drive start timing of the pinion 14 is later than the push-out timing of the pinion 14 and is contacted from this push-out timing. It is set as a timing (time t4) before the timing delayed by the required time Tα (see the two-dot chain line in the figure).
<3. Motor post-drive processing>
Subsequently, the post-motor drive process will be described with reference to FIG. In the figure, as in FIG. 3A, the pulsation of the engine rotation speed decrease trajectory is omitted, and the engine rotation speed NE and the pinion rotation speed Np are respectively the ring gear peripheral speed and the pinion. Peripheral speed is shown.

  This process is a process for operating the motor 12 and the actuator SL1 so as to rotate after the pinion 14 is brought into contact with the ring gear 46 in order to perform cranking. Specifically, as shown in FIG. 3B, when it is determined that the restart condition is satisfied after the reference timing tb during the rotation speed reduction period, the post-motor drive process is performed. Here, in the present embodiment, the push-out timing of the pinion 14 is set as the restart condition establishment timing (time t1), and the rotational drive start timing of the pinion 14 is delayed from the push-out timing of the pinion 14 by the required contact time Tα. Set as timing (time t2).

  By the way, after the motor-first drive process is selected and started, the braking force is applied by the driver's brake operation, or the drive torque of the in-vehicle auxiliary machine is changed, etc. Due to the occurrence of a factor that has not been performed, the predicted value of the updated engine rotation speed decrease trajectory may be lower than the initial predicted value of the decrease trajectory. In this case, the reference timing tb calculated based on the updated predicted value of the lowering trajectory is earlier than the reference timing tb calculated based on the predicted value of the lowering trajectory before the update, and the timing at which the restart condition is satisfied is determined. By determining that what has been determined to be before the reference timing tb is to be after the reference timing tb, the post-motor driving process may be selected before the motor-first driving process is completed. Under such circumstances, if the operation processing of the motor 12 and the actuator SL1 corresponding to the decrease in the predicted value is not performed, the pinion 14 may not be properly meshed with the ring gear 46.

  In other words, for example, in a period from when the pinion 14 is rotationally driven by the motor-first drive processing A to before being pushed out, the motor-first drive processing is performed in a situation where the post-motor drive processing is selected based on the updated predicted value of the lowered trajectory. If the pinion 14 is pushed out in accordance with the initial pinion push-out timing calculated by A, the pinion push-out timing is delayed, and there is a possibility that the timing of meshing the pinion 14 with the ring gear 46 may be delayed. In this case, the pinion rotational speed at the time of contact between the pinion 14 and the ring gear 46 is further increased due to the delay of the push-out timing of the pinion 14, and the actual engine rotational speed at the time of contact is higher than the predicted value of the engine rotational speed. Due to the lowering, the relative rotational speed difference becomes larger, and the pinion 14 may not be properly meshed with the ring gear 46.

  In order to solve such a problem, in the present embodiment, when the post-motor drive process is selected during the period from the start of the motor-first drive process to the completion thereof, the special drive process of the starter 10 is performed. Specifically, when the post-motor driving process is selected during the period from when the pinion 14 is rotationally driven by the motor front driving process A to before the pinion 14 is pushed out, the original driving process according to the motor front driving process A is performed as the special driving process. The process of pushing out the pinion 14 is performed at the selected timing without waiting for the push-out timing of the pinion 14. Accordingly, the rotation speed of the pinion 14 at the time of contact between the pinion 14 and the ring gear 46 is reduced and the relative rotation speed is reduced while avoiding the delay of the timing at which the pinion 14 meshes with the ring gear 46. The pinion 14 can be appropriately meshed with the ring gear 46.

  Here, in the present embodiment, when the motor post-drive process is selected during the period from when the pinion 14 is rotationally driven by the motor pre-drive process A to before being pushed out, the motor drive is further performed as a special drive process of the starter 10. According to the process A, a process of continuing the rotational drive of the pinion 14 is performed. This is to avoid a situation where the completion of restart of the engine 42 is delayed. That is, when the post-motor drive process is selected during the period from when the pinion 14 is rotationally driven to before being pushed out, for example, the rotational drive of the pinion 14 is started at the rotational drive start timing of the pinion 14 according to the post-motor drive process. Accordingly, the difference in the relative rotational speed when the pinion 14 and the ring gear 46 are engaged can be reduced by operating the SL2 drive relay 22 to temporarily stop energization of the motor 12 and then energize again. Conceivable. However, since the required contact time Tα is shorter than the above limit time, the motor 12 is energized, for example, at the push-out timing of the pinion 14 in order to set the rotational drive start timing of the pinion 14 according to the post-motor drive process. When stopped, the timing at which energization of the motor 12 is resumed may be later than the timing at which the pinion 14 contacts the ring gear 46. In this case, the start of cranking may be delayed, and the completion of engine restart may be delayed. For this reason, by performing the process of continuing the rotational drive of the pinion 14, a delay in the rotational drive start timing of the pinion 14 is avoided, and a delay in completing the restart of the engine 42 is avoided.

  On the other hand, when the post-motor drive process is selected during the period from when the pinion 14 is pushed out by the motor-first drive process B to before it is rotationally driven, as a special drive process of the starter 10, the pinion 14 by the motor-first drive process B is used. The process to continue extrusion is performed. This is because the push-out timing of the pinion 14 is the same at the time when the restart condition is satisfied in both the motor-first drive processing B and the motor-after drive processing.

  When the post-motor drive process is selected during the period from when the pinion 14 is pushed out by the motor-first drive process B to before the rotational drive, the updated engine rotation speed is set for the rotational drive start timing of the pinion 14. It is reset based on the predicted value of the decline trajectory. Specifically, for example, since the predicted value of the updated engine rotational speed decrease trajectory is lower than the initial predicted value, the timing at which the engine rotational speed reaches the contact-permitted rotational speed Ne1 is accelerated. The rotational drive start timing of the pinion 14 set based on the lowering trajectory is reset as an earlier timing than the timing set based on the lowering trajectory before the update. Thereby, the relative rotational speed difference when the pinion 14 and the ring gear 46 are engaged with each other can be reduced, and the pinion 14 can be appropriately engaged with the ring gear 46.

  FIG. 4 shows the procedure of the drive control process of the starter 10 including the special drive process according to the present embodiment. This process is repeatedly executed by the ECU 52, for example, at a predetermined cycle (4 msec).

  First, a case will be described in which the post-motor driving process is selected during the period from when the rotation driving of the pinion 14 is started by the motor front driving process A to before the pinion 14 is pushed out.

  In this series of processes, first, in step S10, it is determined whether or not a stop condition for the engine 42 is satisfied. If it is once determined that the stop condition is satisfied in this step, an affirmative determination is made in this step until the restart of the engine 42 is completed.

  If it is determined in step S10 that the stop condition has been established, the process proceeds to step S12, where the predicted value of the lowering trajectory of the engine speed predicted by the lowering trajectory prediction process is acquired, and the lowering trajectory of the acquired lowering trajectory is acquired. The reference timing tb is calculated based on the predicted value and the like.

  In a succeeding step S14, it is determined whether or not a restart condition for the engine 42 is satisfied. If it is once determined that the restart condition is satisfied in this step, an affirmative determination is made in this step after the next time.

  If it is determined in step S14 that the restart condition is satisfied, the process proceeds to step S16 to select which one of the motor front drive process and the motor post drive process is to be adopted. As described above, which process is adopted is determined when it is determined that the timing at which the restart condition is satisfied (the timing at which an affirmative determination is first made in step S14) is earlier than the reference timing tb. When the motor front drive process is selected and it is determined that the restart condition is established after the reference timing, the motor post drive process is selected. Each time the process of this step is performed, the push-out timing and the rotational drive start timing of the pinion 14 are calculated based on the reference timing tb and the predicted value of the lowered trajectory.

  If the motor destination drive process is selected in step S16, the process proceeds to step S17 to determine whether or not the pinion 14 has already been pushed out. Here, if the motor front drive process A is being performed, it is determined in step S18 that it is not the push-out timing of the pinion 14 (SL1 drive relay 40 on-timing), so SL2 drive to drive the pinion 14 to rotate first. The relay 22 is turned on. (Steps S20, S22: YES, Step S24).

  Thereafter, in the period from when the pinion 14 is rotationally driven by the motor-first drive processing A to before the pinion 14 is pushed out, there is no situation in which the predicted value of the updated engine rotational speed decrease trajectory becomes lower than the initial predicted value. When the post-motor drive process is not selected before the pinion 14 is pushed out by the motor drive process A (step S16: YES), the initial push-out timing of the pinion 14 by the motor drive process A (step S17: NO, Step S18: YES) The pinion 14 is pushed out (Step S26). Thereby, cranking is started. Note that when the restart of the engine 42 is completed, this series of processes is temporarily ended (step S28: NO).

  On the other hand, when the updated predicted value of the lowered trajectory is lowered before the pinion 14 is pushed out and the post-motor drive process is selected (step S16: NO), step S30 is performed. Then, the SL1 drive relay 40 is turned on to push out the pinion 14. That is, cranking is started by pushing out the pinion 14 at the timing when the post-motor driving process is selected. At this time, the ON state of the SL1 drive relay 40 is maintained so that the rotational drive of the pinion 14 is continued to avoid delaying the completion of restart of the engine 42. When the process of step S30 is completed, this series of processes is temporarily terminated (step S32: NO).

  Next, a case will be described in which the post-motor drive process is selected in the period from when the pinion 14 is pushed out by the motor-first drive process B to before the rotational drive.

  When it is determined that it is the push-out timing of the pinion 14 (step S17: NO, step S18: YES) under the situation where the motor-driven process is selected (step S16: YES), the pinion is performed by the motor-driven drive process B. A process for rotationally driving 14 is performed. Specifically, first, in step S26, the SL1 drive relay 40 is turned on to push out the pinion 14. And it waits until it becomes the rotational drive start timing of the pinion 14 (step S28: YES, step S34: NO).

  Here, when the post-motor drive process is not selected during the standby (step S16: YES), the rotation drive start timing (SL2 drive relay on timing) of the pinion 14 by the motor first drive process B is then performed (step S17: YES). Steps S28 and S34: YES) The pinion 14 is driven to rotate (Step S36). Thereby, cranking is started.

  On the other hand, when the post-motor drive process is selected during the standby until the rotational drive start timing of the pinion 14 is reached (step S16: NO), according to the initial push-out timing of the pinion 14 by the motor front drive process B. Cranking is started by continuing to push out the pinion 14 and then rotating the pinion 14 (steps S32 and S38: YES, step S40). At this time, the rotation drive start timing of the pinion 14 is calculated based on the updated predicted value of the engine rotation speed decrease trajectory.

  FIG. 5 shows an example of a special case drive process of the starter 10 according to the present embodiment.

  First, FIG. 5A shows an example of a case where the post-motor driving process is selected during a period from when the pinion 14 is rotationally driven by the motor front driving process A to before the pinion 14 is pushed out. Specifically, FIG. 5 (a-1) shows the transition of whether or not the motor front drive process is selected, and FIG. 5 (a-2) shows the situation where the motor post-drive process is selected. FIG. 5 (a-3) shows the transition of the operation state of the SL1 drive relay 40, and FIG. 5 (a-4) shows the transition of the operation state of the SL2 drive relay 22. .

  In the illustrated example, at time t1 within the rotation speed reduction period, it is determined that the storage of the angular speed in the previous rotation pulsation period has been completed and the engine rotation speed reduction trajectory prediction process can be executed. Thereafter, at time t2, when the restart condition of the engine 42 is satisfied in a situation where the motor tip drive process A is selected, the rotation drive start timing (time t2) and the push timing (time t2) of the pinion 14 by the motor tip drive process A are satisfied. t4) is calculated, and the rotational drive of the pinion 14 is started. Thereafter, due to the brake operation or the like, at the time t3 before the push-out timing of the pinion 14 (time t4), the updated predicted value of the engine rotation speed decrease trajectory becomes lower than the initial predicted value. The post-motor drive process is selected, and the SL1 drive relay 40 is turned on to immediately push out the pinion 14 at this selection timing. At this time, the delay of restart completion due to the timing when the limit time Tβ elapses after the pinion 14 is pushed out from the timing when the required contact time Tα elapses after the pinion 14 is pushed out is avoided. Therefore, the rotational drive of the pinion 14 is continued. Thereby, the pinion 14 can be appropriately meshed with the ring gear 46. Thereafter, the SL1 drive relay 40 and the SL2 drive relay 22 are turned off at time t5 when it is determined that the restart of the engine 42 is completed by cranking.

  Next, FIG. 5B shows an example when the post-motor drive process is selected in the period from when the pinion 14 is pushed out by the motor-first drive process B to before the rotational drive. Specifically, FIG. 5 (b-1) to FIG. 5 (b-4) correspond to the previous FIG. 5 (a-1) to FIG. 5 (a-4).

  In the example shown in the figure, when the restart condition of the engine 42 is satisfied in the situation where the motor destination drive process B is selected at time t2, the push-out timing (time t2) of the pinion 14 by the motor destination drive process B and the rotational drive The start timing (time t5) is calculated, and the pinion 14 is pushed out. Thereafter, due to the brake operation or the like, at time t3, the post-motor drive process is selected due to the update of the predicted value of the lowered trajectory. Under such circumstances, the push-out of the pinion 14 by the motor-first drive process B is continued, and the rotation drive start timing (time t4) of the pinion 14 is reset based on the updated predicted value of the lowered trajectory and the like. . After that, the pinion 14 is rotationally driven at the reset rotation start timing of the pinion 14. Thereby, the pinion 14 can be appropriately meshed with the ring gear 46.

  As described above, in the present embodiment, when the post-motor driving process is selected in a period from when one of the push-out and the rotational driving of the pinion 14 by the motor-first driving process is started and before the other is started, By performing the special drive process of the starter 10, the pinion 14 can be appropriately meshed with the ring gear 46.

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

  (1) When the post-motor drive process is selected during the period from when the pinion 14 is rotationally driven by the motor-first drive process A to before being pushed out, the process of pushing out the pinion 14 at the timing when the post-motor drive process is selected. went. Thereby, the delay of the timing which meshes | pinizes the pinion 14 with the ring gear 46 can be avoided, and the pinion 14 can mesh | engage appropriately with the ring gear 46 by extension.

  (2) When the post-motor drive process is selected during the period from when the pinion 14 is rotationally driven by the motor-first drive process A to before the pinion 14 is pushed out, the process of continuing the rotational drive of the pinion 14 was performed. Thereby, the delay of the meshing timing of the pinion 14 and the ring gear 46 due to the on / off limiting process can be avoided, and as a result, the pinion 14 can be meshed appropriately with the ring gear 46.

  (3) When the post-motor drive process is selected during the period from when the pinion 14 is pushed out by the motor drive process B to before being driven to rotate, the process of continuing the push-out of the pinion 14 by the motor drive process B went. Thereby, the pinion 14 can be appropriately meshed with the ring gear 46.

  (4) When the post-motor drive process is selected in the period from when the pinion 14 is pushed out by the motor-first drive process B to before the rotational drive, based on the predicted value of the updated engine rotation speed decrease trajectory, The rotational drive start timing of the pinion 14 was reset. Thereby, the pinion 14 can be appropriately meshed with the ring gear 46.

  (5) Based on the predicted value of the engine rotation speed decrease trajectory, the motor front drive processing and the motor post drive processing are performed so that the relative rotational speed difference at the timing when the pinion 14 contacts the ring gear 46 is equal to or less than the specified value ΔN. It was made to select which one to adopt. In this case, the rotation speed of the pinion 14 at the timing when the pinion 14 contacts the ring gear 46 due to the update of the predicted value of the decrease trajectory of the engine rotation speed is appropriate for making the relative rotation speed difference equal to or less than the specified value. Therefore, the post-motor drive process is likely to be selected before the motor-first drive process is completed. For this reason, this embodiment, which selects which one of the motor front drive process and the motor post-drive process to adopt in the above-described manner, has high utility value of the special drive process of the starter 10.

(Other embodiments)
The above embodiment may be modified as follows.

  -The method of predicting the engine rotation speed decrease trajectory is not limited to the one exemplified in the above embodiment. For example, instead of the loss torque in the previous rotation pulsation period, the amount of decrease in engine rotation speed in each section of the previous rotation pulsation period may be used for prediction. Specifically, for example, the engine rotation speed decrease amount in each section of the previous rotation pulsation period is stored, and the engine rotation speed decrease trajectory is predicted by subtracting the stored decrease amount from the current engine rotation speed. That's fine.

  -The setting method of the rotational drive start timing of the pinion 14 by the post-motor drive process is not limited to that exemplified in the above embodiment. For example, the rotational drive start timing may be set as the timing after the pinion 14 contacts the ring gear 46. Specifically, the rotational drive start timing may be set as a timing delayed from the push-out timing of the pinion 14 for a time slightly longer than the required contact time Tα.

  DESCRIPTION OF SYMBOLS 10 ... Starter, 12 ... Motor, 14 ... Pinion, 16 ... Actuator, 42 ... Engine, 44 ... Crankshaft, 46 ... Ring gear, 50 ... Crank angle sensor, 52 ... ECU (one implementation of automatic stop / start control device for engine) Form).

Claims (5)

A starter is provided that includes a motor that rotationally drives the pinion, and an actuator that pushes the pinion toward the ring gear so that the pinion contacts and meshes with a ring gear connected to an output shaft of the engine. Applied to a vehicle and automatically stops the engine when a predetermined stop condition is satisfied, and then restarts the engine by performing cranking by the starter when a predetermined restart condition is satisfied In the start control device,
Predicting means for updating the predicted decrease trajectory at a predetermined period while predicting the decrease trajectory of the engine rotation speed after the automatic stop of the engine each time;
Motor driven drive that performs operation processing of the motor and the actuator so that the pinion is rotated before being brought into contact with the ring gear in order to perform the cranking in a situation where the engine rotation speed is in a predetermined high rotation range. Means,
Post-motor drive that performs operation processing of the motor and the actuator so that the pinion is rotated after being brought into contact with the ring gear to perform the cranking in a situation where the engine rotation speed is in a predetermined low rotation region. Means,
A selection means for selecting which of the motor front drive means and the motor post drive means to adopt the operation process based on the lowered trajectory predicted each time by the prediction means when the restart condition is satisfied; ,
When the operation processing by the post-motor driving means is selected by the selection means during a period from when the pinion is rotationally driven by the motor front drive means to before being pushed out, the pinion is pushed out at the selected timing. And an engine automatic stop / start control device. The vehicle is provided with a switch operated by the motor front drive means and the motor post drive means in order to switch between energization to the motor or stop of energization,
Further comprising limiting means for limiting the operation of the switch so that the switching interval of the switch is not less than a specified time,
The specified time is longer than the time required from when the pinion is pushed out to contact the ring gear,
When the operation processing by the post-motor driving unit is selected by the selection unit during a period from when the pinion is rotationally driven by the motor front driving unit to before being pushed out, the motor front driving unit 2. The engine automatic stop / start control apparatus according to claim 1, wherein the rotation drive of the pinion is continued. The post-motor drive means sets the pinion push-out timing as a timing at which the restart condition is satisfied, and sets the pinion rotation drive start timing as a timing delayed by a predetermined time from the push-out timing. Is,
The motor front drive means sets the push-out timing of the pinion as a timing at which the restart condition is satisfied, and sets the rotational drive start timing of the pinion after the push-out timing and from the push-out timing to the predetermined timing. It is provided with setting means for setting as a timing before the time delayed time,
When the operation process by the post-motor drive means is selected by the selection means during the period from when the pinion is pushed out by the setting means to before being driven to rotate, the control means The automatic stop / start control device for an engine according to claim 1 or 2, wherein the push-out of the pinion is continued.   The control means is updated by the prediction means when the selection process selects the operation process by the post-motor drive means during a period from when the pinion is pushed out by the setting means to before rotation driving. 4. The automatic stop / start control apparatus for an engine according to claim 3, wherein the rotation driving start timing of the pinion is reset based on the lowering trajectory.   The selection means has a difference between a rotation speed of the pinion and a rotation speed of the ring gear at a timing when the pinion comes into contact with the ring gear based on a lowered trajectory predicted each time by the prediction means. As described above, the engine automatic stop / start control device according to any one of claims 1 to 4, wherein it is selected which of the operation processes is adopted.

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