JP2011140939A - Engine automatic stop-and-start control appartus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the driving timing of a pinion with high accuracy when shifting the pinion to a ring gear for engaging them during a drop of an engine rotational speed at the engine automatic stop. <P>SOLUTION: In an idle stop system, during a drop of an engine rotational speed when automatically stopping the engine 21, by repeating multiple times processing of predicting an engine rotational speed or an angular speed at next calculation timing at a predetermined calculation cycle based on loss torque (friction torque), an engine rotation speed or an angular speed and inertia of the engine 21 and predicting an engine rotational speed or an angular speed at further next timing based on the predicted data, a trajectory of the drop of the engine rotational speed to the calculation timing multiple times later is predicted, and a last TDC in the forward rotation direction is determined based on the predicted data. The driving timing of the pinion 13 of a starter 11 is determined with reference to the last TDC in the forward rotation direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  According to the present invention, a starter pinion is jumped into a ring gear connected to an engine crankshaft at a predetermined timing in preparation for the next restart during a period when the engine rotational speed when the engine is automatically stopped decreases. The present invention relates to an engine automatic stop / start control device to be matched.

  This type of engine automatic stop / start control device is, as described in Patent Document 1 (Japanese Patent Laid-Open No. 2005-330813), a period during which the engine rotation speed when the engine is automatically stopped (engine rotation drop period). ), When the restart request is generated, the starter motor is energized to rotate the pinion, and the engine rotation speed (link gear) after the elapse of a predetermined time corresponding to the time required for the pinion biting operation. Rotation speed) is predicted, and the timing at which the pinion rotation speed is synchronized with the engine rotation speed (link gear rotation speed) is predicted, and the pinion engagement timing is determined so that the pinion jumps into the ring gear and meshes at that timing. There is something to do.

Japanese Patent Laying-Open No. 2005-330813

  According to the research results of the present inventors, the engine rotation speed (link gear rotation speed) and the pinion rotation speed are predicted during the engine rotation descent period when the engine is automatically stopped, as in Patent Document 1 above. Even if the pinion rotation speed is predicted to synchronize with the engine rotation speed (link gear rotation speed) and the pinion engagement operation is started so that the pinion jumps into the ring gear and meshes at that timing, the following It turns out to have problems.

  That is, the engine rotation behavior during the engine rotation descent period does not decrease linearly, but the engine rotation speed decreases while pulsating, and the rotation speed of the ring gear connected to the engine crankshaft also pulsates. While descending. For this reason, even if the engine rotation speed (link gear rotation speed) after a predetermined time corresponding to the time required for the pinion biting operation is predicted, the pinion rotation speed is the engine rotation speed (link gear rotation speed). There is a possibility that the timing to synchronize with the pinion cannot be accurately predicted, and the difference between the pinion rotation speed and the link gear rotation speed when the pinion is engaged may increase. As shown in FIG. 4, when the difference (relative rotational speed) between the pinion rotation speed and the link gear rotation speed at the time of pinion engagement increases, the noise level at the time of pinion engagement increases.

  Therefore, the problem to be solved by the present invention is an engine automatic stop / start control device that can accurately control the drive timing of the pinion when the pinion jumps into the ring gear and meshes during the engine rotation descent period during automatic engine stop. Is to provide.

  In order to solve the above-described problem, the invention according to claim 1 provides a starter pinion of the engine at a predetermined timing in preparation for the next restart in a period when the engine rotation speed when the engine is automatically stopped decreases. In an engine automatic stop / start control device that jumps into and meshes with a ring gear connected to a crankshaft, the last TDC in the forward rotation direction (top dead) during a period when the engine rotation speed when the engine is automatically stopped decreases. A last TDC judging means for judging the point) and a control means for determining the drive timing of the pinion based on the last TDC in the forward rotation direction judged by the last TDC judging means.

  In this configuration, since the last TDC in the forward rotation direction is determined during the engine rotation descent period when the engine is automatically stopped, the pinion drive timing is determined with reference to the last TDC in the forward rotation direction. You can make a good decision.

  By the way, after the engine rotation passes through the last TDC in the forward rotation direction during the engine rotation descent period, the piston reverses without overcoming the next TDC, so that the engine rotation speed is reduced before reaching the next TDC. 0 [rpm] or less.

  In consideration of such an engine rotation descent trajectory, as in claim 2, the last TDC determination means performs the next calculation based on at least the engine rotation speed or the angular speed at a predetermined calculation cycle when automatically stopping the engine. Predict engine rotation descent trajectory by predicting engine rotation speed or angular velocity at each calculation timing up to the timing or multiple calculation timings ahead, and determine the last TDC in the forward rotation direction based on the predicted engine rotation descent trajectory You may make it do. In this way, the TDC immediately before the predicted value of the engine rotation descent trajectory is 0 [rpm] or less can be determined as the last TDC in the forward rotation direction.

  In this case, the engine rotational behavior after the combustion of the engine is stopped (after the fuel cut) changes due to the influence of engine loss torque (friction torque) and inertia. In consideration of this point, as in claim 3, the last TDC determination means considers at least one of engine loss torque, loss energy, and inertia at a predetermined calculation cycle when the engine is automatically stopped. It is also possible to predict the engine rotation speed or the angular speed at each calculation timing up to the calculation timing or the calculation timing of a plurality of times ahead. In this way, the prediction accuracy of the engine rotation descending trajectory can be increased, and the determination accuracy of the last TDC in the forward rotation direction can be improved.

  According to another aspect of the present invention, when the engine is automatically stopped, the last TDC determination means predicts the engine rotation speed or angular velocity at the next calculation timing based on at least the engine rotation speed or angular velocity at a predetermined calculation cycle. Then, based on the prediction data, the process of predicting the engine rotation speed or angular speed at the next calculation timing is repeated a plurality of times to predict and predict the engine rotation descent trajectory up to the calculation timing ahead a plurality of times. The last TDC in the forward rotation direction may be determined based on the engine rotation descending trajectory. In this way, it is possible to accurately predict the engine rotation descent trajectory up to the calculation timing ahead several times, and to accurately determine the last TDC in the forward rotation direction based on the predicted engine rotation descent trajectory. it can.

  Further, as in claim 5, the last TDC determining means predicts time tTDC until reaching the next TDC, and means predicting time t0rpm until the engine speed reaches 0 [rpm]. And the predicted value of the time tTDC until the next TDC is reached and the predicted value of the time t0 rpm until the engine speed reaches 0 [rpm], and based on the comparison result, The TDC may be determined. In this way, it is possible to easily determine whether or not the current TDC is the last TDC in the forward rotation direction.

FIG. 1 is a schematic configuration diagram of an engine start control system according to Embodiment 1 of the present invention. FIG. 2 is a diagram illustrating a prediction result of the engine rotation descent trajectory of the first embodiment. FIG. 3 is a diagram for explaining a prediction calculation method of the engine rotation descent trajectory according to the first embodiment. FIG. 4 is a diagram showing data obtained by measuring the relationship between the difference between the pinion rotation speed and the link gear rotation speed when the pinion is engaged and the noise level. FIG. 5 is a flowchart showing the flow of processing of the loss torque calculation routine of the first embodiment. FIG. 6 is a flowchart showing the flow of the last TDC determination routine of the first embodiment. FIG. 7 is a flowchart showing the flow of the final TDC determination routine of the second embodiment. FIG. 8 is a time chart for explaining a method of determining the last TDC in the forward rotation direction according to the second embodiment. FIG. 9 is a diagram for explaining a method of predicting the engine rotation descent trajectory according to the third embodiment. FIG. 10 is a flowchart showing the flow of the final TDC determination routine of the third embodiment.

  Hereinafter, three embodiments 1 to 3 embodying the mode for carrying out the present invention will be described.

A first embodiment of the present invention will be described with reference to FIGS.
First, the schematic configuration of the engine automatic stop / start control system will be described with reference to FIG.
The starter 11 is a so-called pinion push-out starter, and includes a motor 12, a pinion 13 that is rotationally driven by the motor 12, a pinion actuator 14 that pushes out the pinion 13, and the like. And can be operated individually. The pinion 13 is provided so as to be movable in the axial direction. The pinion actuator 14 is provided with a plunger 15 and a solenoid 16 that drives the plunger 15, and the driving force of the plunger 15 is transmitted to the pinion 13 via a lever 17 or the like.

  A relay 19 is provided between the battery 18 and the pinion actuator 14, and the ECU 20 (engine control circuit) turns on the relay 19 to turn on the energization of the pinion actuator 14 to move the plunger 15 in the pinion pushing direction. By moving the pinion 13, the pinion 13 is pushed out and engaged with the ring gear 23 connected to the crankshaft 22 of the engine 21.

  Further, a switching element 24 is provided between the battery 18 and the motor 12, and the ECU 20 controls on / off of the switching element 24 and duty-controls the energization of the motor 12, thereby controlling the rotation speed of the pinion 13. It comes to control.

  The engine 21 is provided with a crank angle sensor 25 that outputs a crank pulse every time the crankshaft 22 rotates a predetermined crank angle (for example, 30 ° C.), and the engine rotational speed or angular speed is determined based on the output interval of the crank pulse. While being calculated, the crank pulse is counted to detect the crank angle. The crank angle reference position may be detected by a missing tooth portion (a portion where one to several pulses are not continuously output) of the crank angle sensor 25, or the position at which the cam pulse is output from the cam angle sensor. The crank angle reference position may be used.

  The ECU 20 is composed mainly of a microcomputer, and controls the fuel injection amount and ignition timing of the engine 21 according to the engine operating state by executing various engine control programs stored in the built-in ROM.

  Further, the ECU 20 executes engine automatic stop / start control (so-called idle stop control) by executing an engine automatic stop / start control routine (not shown). In this automatic engine stop / start control, when the driver performs a deceleration operation (accelerator fully closed, brake operation, etc.) while the vehicle is running, the vehicle enters a predetermined deceleration state that may cause the vehicle to stop, or the vehicle is stopped. When the brake operation is continued, it is determined that an automatic stop request (idle stop request) has occurred, and combustion (fuel injection and / or ignition) of the engine 21 is stopped to automatically start the engine 21. Stop. Further, in the first embodiment, just before the engine 21 is automatically stopped, as will be described later, in preparation for the next restart, the pinion actuator 14 is energized to cause the pinion 13 to jump into the ring gear 23 on the engine 21 side. The pinion 13 is kept engaged with the ring gear 23 on the engine 21 side until the next restart is completed.

  After that, it is determined that a restart request has occurred when the driver performs a preparation operation for starting the vehicle (brake release, operation of the shift lever to the drive range, etc.) or a start operation (depressing the accelerator, etc.). Then, the motor 12 of the starter 11 is energized to rotationally drive the pinion 13 to crank the engine 21, restart the fuel injection and restart it. In addition, the engine 11 may be restarted when a restart request is generated from a control system of an in-vehicle device such as a battery charge control system or an air conditioner. At the time of restart, when the engine speed exceeds the start completion determination threshold value, it is determined that restart has been completed, and energization of the motor 12 of the starter 11 is stopped and energization of the pinion actuator 14 is stopped. Then, the pinion 13 is extracted from the ring gear 23 on the engine 21 side and returned to the original position by a return spring (not shown).

  Further, the ECU 20 executes the routines shown in FIGS. 5 and 6 to be described later, thereby predicting the engine rotation descent trajectory during the engine rotation descent period when the engine 21 is automatically stopped, and based on the prediction data. It functions as a last TDC determination unit that determines the last TDC (top dead center) in the forward rotation direction, and also functions as a control unit that determines the drive timing of the pinion 13 of the starter 11 based on the last TDC in the forward rotation direction. To do.

Here, a method for predicting the engine rotation descent trajectory of the first embodiment will be described.
In the following description, an example using a crank angle sensor 25 that outputs a crank pulse every 30 ° C. will be described. At the time of the automatic engine stop, the angular speed ω [rad / sec] is calculated by the following equation for every 30 ° C. when the crank pulse is input from the crank angle sensor 25 to the ECU 20 during the period when the engine rotational speed decreases.
ω = 30 × 2π / (360 × tp)
tp: Crank pulse interval [sec]

  From the above equation, the angular velocity ω [0, i-1] at a crank angle of 0 ° A after the TDC of the 180 ° A section [i-1] in the previous time, the angular velocity ω [30, i-1] at a crank angle of 30 ° A , Angular speed ω [60, i-1] with a crank angle of 60 ° C, angular speed ω [90, i-1] with a crank angle of 90 ° C, angular speed ω [120, i-1] with a crank angle of 120 ° C, An angular velocity ω [150, i-1] at an angle 150 ° C. and an angular velocity ω [0, i] at a crank angle 0 ° A after TDC in the current 180 ° A section [i] are calculated.

  Further, loss torque T [0-30, i-1] from crank angle 0 ° C to 30 ° A after TDC of the previous 180 ° C section [i-1], crank angle 30 ° A to 60 ° A Loss torque T [30-60, i-1], loss torque T [60-90, i-1] from crank angle 60 ° C. to 90 ° C., and loss torque T [ 90-120, i-1], loss torque T [120-150, i-1] from crank angle 120 ° C to 150 ° A, after TDC of crank angle 150 ° A to current 180 ° A section [i] The loss torque T [150-0, i-1] up to 0 ° C is calculated.

T [0-30, i-1] = − J · (ω [30, i-1] ² −ω [0, i-1] ² ) / 2
T [30-60, i-1] = −J ・ (ω [60, i-1] ² −ω [30, i-1] ² ) / 2
T [60-90, i-1] = −J · (ω [90, i-1] ² −ω [60, i-1] ² ) / 2
T [90-120, i-1] = − J · (ω [120, i-1] ² −ω [90, i-1] ² ) / 2
T [120-150, i-1] = − J · (ω [150, i-1] ² −ω [120, i-1] ² ) / 2
T [150-0, i-1] = − J · (ω [0, i] ² −ω [150, i-1] ² ) / 2

Here, J is the inertia of the engine 21. The calculated values of the loss torques T [0-30, i-1] to T [150-0, i-1] are updated and stored in the registers (see FIG. 3).
Then, at 30 ° C. A (current time) after TDC of the current 180 ° C. section [i], the angular velocity ω [30, i] is calculated, and the loss torque T [0-30, i] is calculated in the same manner. This loss torque T [0-30, i] is stored in a register.

At this time, loss energy may be stored in a register instead of loss torque. The loss energy is obtained by dividing the loss torque by J / 2.
For example, the loss energy E [0-30, i-1] from the crank angle 0 ° C. to 30 ° C. A after the TDC of the previous 180 ° C. section [i-1] is obtained by the following equation.
E [0-30, i-1] = T [0-30, i-1] / (J / 2)
= − (Ω [30, i-1] ² −ω [0, i-1] ² )

  Examples of the loss energy include pumping loss of the engine 21, friction of the engine 21, and fluid loss of an alternator, a compressor, and a mission connected to the engine 21 via a belt.

  After that, as shown in FIG. 3, the current 180 ° C. section [i-1] is used for the current 180 ° torque loss T [30-60, i-1] from the crank angle 30 ° A to 60 ° C. The predicted angular velocity ω ′ [60, i] of the crank angle 60 ° C. after TDC in the ° C interval [i] is calculated, and the predicted arrival time t [30 until the crank angle 30 ° A reaches 60 ° C. -60, i] is calculated, and the loss torque T [60-90, i-1] from the crank angle 60 ° C to 90 ° C in the previous 180 ° A section [i-1] and the predicted angular velocity ω are calculated. '[60, i] is used to calculate the predicted angular velocity ω' [90, i] of the crank angle 90 ° C after TDC in the current 180 ° C section [i] and from the crank angle 60 ° A to 90 ° C. The estimated arrival time t [60-90, i] until reaching ℃ A is calculated, and the loss torque T [from the crank angle 90 ℃ A to 120 ℃ A in the previous 180 ℃ A section [i-1] is calculated. 90-120, i-1] and above Using the predicted angular velocity ω ′ [90, i], the predicted angular velocity ω ′ [120, i] of the crank angle 120 ° C. after the TDC of the current 180 ° A section [i] is calculated, and the crank angle 90 ° C. The engine rotation descent trajectory is predicted by repeating the process of calculating the predicted arrival time t [90-120, i] from A to 120 ° C. A (see FIG. 2).

  This prediction calculation is executed using the time until the next crank pulse is input every time the crank pulse is input (every 30 ° C. A), and the prediction data of the engine rotation orbit is updated each time. If the calculation time until the next crank pulse is input has enough time, the engine rotation descent trajectory until the engine speed reaches 0 [rpm] is predicted. If the calculation time is insufficient, the prediction calculation is performed. Is cut off halfway, and the process proceeds to a new prediction calculation using the actual angular velocity at the next crank angle. It goes without saying that the prediction calculation may be performed by converting the angular velocity into the engine rotation speed.

  After the engine rotation passes through the last TDC in the forward rotation direction during the engine rotation descent period, the piston rotates reversely without getting over the next TDC, so the engine rotation speed becomes 0 [0] before reaching the next TDC. rpm] or less.

  Therefore, if the engine rotation speed trajectory until the engine speed reaches 0 [rpm] is predicted by the above-described method, the last TDC before the engine speed reaches 0 [rpm] is determined as the forward rotation direction. Can be determined as the last TDC. Then, the energization timing of the motor 12 of the starter 11 and the drive timing of the pinion 13 may be determined based on the last TDC in the forward rotation direction.

Alternatively, for each TDC (or every 180 ° C. A), a process for predicting the engine rotational descending trajectory up to the next TDC is executed, and the engine rotational speed becomes 0 [rpm] or less before reaching the next TDC. It may be determined whether or not the current TDC is the last TDC in the forward rotation direction.
Hereinafter, a method for determining the last TDC in the forward direction that embodies this will be described with reference to the routines shown in FIGS.

[Ross torque calculation routine]
The loss torque calculation routine of FIG. 5 is repeatedly executed by the ECU 20 at a predetermined cycle while the engine is operating (during the power-on period of the ECU 20). Each time a crank pulse is input to the ECU 20, a loss torque of the engine 21 at the crank angle is calculated and updated and stored in a register corresponding to the crank angle.

  When this routine is started, first, at step 101, it is determined whether or not the engine speed is decreasing when the engine is automatically stopped. Since it is not necessary to calculate the loss torque used for prediction, this routine is terminated as it is.

On the other hand, if it is determined in step 101 that the engine speed is decreasing when the engine is automatically stopped, the process proceeds to step 102 where it is determined whether or not a crank pulse is input from the crank angle sensor 25 to the ECU 20. Wait until is entered. Each time a crank pulse is input, the process proceeds to step 103 to calculate an angular velocity ω when the crank pulse is input this time.
ω = 30 × 2π / (360 × tp)
tp: Crank pulse interval [sec]

  Thereafter, the process proceeds to step 104, and the loss torque is calculated by the equation of FIG. 3 using the angular velocity ω at the time of the present crank pulse input, the angular velocity ω before 30 ° C. and the inertia J of the engine 21, and updated and stored in the register. .

  By repeating the above processing, each time a crank pulse is input to the ECU 20 while the engine rotation is decreasing when the engine is automatically stopped, the loss torque of the engine 21 at the crank angle is calculated and updated to the register corresponding to the crank angle. Repeat the process to memorize.

[Last TDC determination routine]
The last TDC determination routine in FIG. 6 is repeatedly executed by the ECU 20 at a predetermined cycle during engine operation (during the power-on period of the ECU 20), and serves as the last TDC determination means in the claims.

  When this routine is started, first, at step 201, it is determined whether or not the engine speed is decreasing when the engine is automatically stopped. Since it is not necessary to determine the TDC, the routine is terminated as it is.

  On the other hand, if it is determined in step 201 that the engine speed is decreasing when the engine is automatically stopped, the process proceeds to step 202, where it is determined whether or not the current crank angle is TDC, and waiting until TDC is reached. To do. When TDC is reached, the process proceeds to step 203, and the loss torque of the engine 21 stored in the register is read. As this loss torque, the loss torque calculated at the time of crank pulse input before 150 ° C. A and stored in the register is used. Thereafter, the process proceeds to step 204, and the predicted angular velocity ω ′ at the input timing of the next crank pulse is calculated using the loss torque, and the predicted arrival time t until the input timing of the next crank pulse is calculated.

  Thereafter, the process proceeds to step 205, where it is determined whether or not the current TDC is the last TDC in the forward rotation direction based on whether or not the predicted angular velocity ω ′ at the input timing of the next crank pulse is 0 or less. . If it is determined in step 205 that the predicted angular velocity ω ′ is not less than or equal to 0, the process proceeds to step 206 to determine whether or not the prediction up to the next TDC has been completed. As a result, if it is determined that the prediction up to the next TDC has not been completed yet, the process proceeds to step 207, the loss torque of the engine 21 is calculated and stored in the register, and the processes of steps 203 and 204 described above are repeated. Then, using the loss torque and the predicted angular velocity ω ′, the process of calculating the predicted angular velocity ω ′ and the predicted arrival time t at the input timing of the next crank pulse is repeated.

  Such predicted angular velocity ω ′ and predicted arrival time t for every 30 ° C. are repeated until the next TDC. Before the prediction up to the next TDC is finished, in step 205, the predicted angular velocity ω ′ is set to 0 or less. If it is determined, the routine proceeds to step 208, where it is determined that the current TDC is the last TDC in the forward rotation direction, and this routine is terminated.

  On the other hand, if the predicted angular velocity ω ′ does not become 0 or less until the next TDC, it is determined that the current TDC is not the last TDC in the forward rotation direction, and this routine is terminated.

  According to the first embodiment described above, the engine rotation descent trajectory is predicted during the engine rotation descent period when the engine is automatically stopped, and the last TDC in the forward rotation direction is determined based on the prediction data. Thus, the last TDC in the forward rotation direction can be determined before the engine rotation speed (angular velocity) becomes 0 or less, and the pinion 13 of the starter 11 is driven based on the last TDC in the forward rotation direction. Timing can be determined with high accuracy.

  In the final TDC determination routine shown in FIG. 6, the engine rotation drop trajectory up to the next TDC is predicted for each TDC (every 180 ° C. A). For example, the engine rotation drop to TDC after 360 ° C. has elapsed. The period for predicting the engine rotation descent trajectory may be changed as appropriate, for example, the trajectory may be predicted.

  Further, in the last TDC determination routine of FIG. 6, the calculation of the predicted angular velocity ω ′ and the predicted arrival time t at the crank pulse input timing is repeated to predict the engine rotation descent trajectory. For example, TDC (180 ° C. A) The prediction calculation cycle may be changed as appropriate, such as calculating the predicted angular velocity ω ′ at the timing and the predicted arrival time t.

  Next, Embodiment 2 of the present invention will be described with reference to FIGS. However, substantially the same parts as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted or simplified, and different parts are mainly described.

  In the second embodiment, as shown in FIG. 8, during the engine rotation descent at the time of automatic engine stop, the engine rotation descent trajectory based on the history data of the engine rotation speed (angular velocity) up to that point in a predetermined calculation cycle. And predicting the time tTDC until reaching the next TDC based on the prediction data, and predicting the time t0rpm until the engine speed reaches 0 [rpm], and reaching the next TDC The predicted value of the time tTDC until the engine rotational speed reaches 0 [rpm] is compared with the predicted value of the time t0rpm until the last TDC in the forward rotation direction is determined based on the comparison result. Yes.

  The determination process of the last TDC in the forward rotation direction of the second embodiment is executed by the ECU 20 according to the last TDC determination routine of FIG. This routine is repeatedly executed by the ECU 20 at a predetermined cycle (for example, 180 ° C. A cycle) during engine operation, and serves as a final TDC determination means in the claims.

  When this routine is started, it is first determined in step 301 whether or not the engine speed is decreasing when the engine is automatically stopped. If the engine speed is not decreasing when the engine is automatically stopped, the last of the forward rotation direction is determined. Since it is not necessary to determine the TDC, this routine is terminated as it is.

  On the other hand, if it is determined in step 301 that the engine speed is decreasing when the engine is automatically stopped, the process proceeds to step 302, and the engine rotation orbit is predicted based on the history data of the engine speed up to now. Thereafter, the process proceeds to step 303, where a predicted time tTDC until reaching the next TDC is calculated based on the predicted data of the engine rotational descending trajectory. In the next step 304, based on the predicted data of the engine rotational descending trajectory. The estimated time t0 rpm until the engine speed reaches 0 [rpm] is calculated.

  Thereafter, the process proceeds to step 305, where it is determined whether or not the predicted time tTDC until reaching the next TDC is longer than the predicted time t0 rpm until the engine speed reaches 0 [rpm]. As a result, if it is determined that the predicted time tTDC until the next TDC is reached is longer than the predicted time t0 rpm until the engine speed reaches 0 [rpm], the engine speed is reached before the next TDC is reached. Since this means that the speed reaches 0 [rpm], the routine proceeds to step 306, where the current TDC is determined as the last TDC in the forward rotation direction, and this routine is terminated.

  On the other hand, if it is determined in step 305 that the predicted time tTDC until reaching the next TDC is shorter than the predicted time t0 rpm until the engine speed reaches 0 [rpm], the current TDC is The routine is terminated by determining that it is not the last TDC in the forward rotation direction.

  Since the last TDC determination routine of FIG. 8 described above is repeatedly executed at a predetermined cycle (for example, 180 ° C. A cycle), the last TDC in the forward rotation direction can be determined during the engine rotation drop during the automatic engine stop.

  In the first embodiment, when the engine 21 is automatically stopped, the engine rotation speed or angular speed at the next calculation timing is predicted based on the loss torque, engine rotation speed or angular speed, and inertia of the engine 21 at a predetermined calculation cycle. Based on the prediction data, the process of predicting the engine rotation speed or angular velocity at the next calculation timing is repeated a plurality of times to predict the engine rotation descent trajectory up to the calculation timing ahead a plurality of times. In the third embodiment of the present invention, as shown in FIG. 9, when the engine 21 is automatically stopped, at a predetermined calculation cycle, the calculation is performed a plurality of times from the next calculation timing based on at least the engine rotational speed or the angular speed ω0. The engine rotation speed or angular speed ω1, ω2, ..., ωn at each calculation timing up to the timing And the final TDC in the forward rotation direction is determined based on the predicted engine rotation descent trajectory.

  Hereinafter, the processing content of the last TDC determination routine of FIG. 10 executed in the third embodiment will be described. This routine is repeatedly executed at a predetermined cycle by the ECU 20 during engine operation (during the power-on period of the ECU 20), and serves as a final TDC determination means in the claims.

  When this routine is started, first, at step 401, it is determined whether or not the engine speed is decreasing when the engine is automatically stopped. If the engine speed is not decreasing when the engine is automatically stopped, the last of the forward rotation direction is determined. Since it is not necessary to determine the TDC, this routine is terminated as it is.

  On the other hand, if it is determined in step 401 that the engine speed is decreasing when the engine is automatically stopped, the process proceeds to step 402 and waits until a crank pulse is input. Then, the engine rotation descent trajectory is predicted by predicting the angular velocities ω1 ′, ω2 ′,..., Ωn ′ at the respective calculation timings from the next calculation timing to the calculation timing of a plurality of times ahead. Here, the angular velocities ω1 ′, ω2 ′,..., Ωn ′ at each calculation timing are predicted in consideration of at least one of the loss torque and inertia of the engine 21 based on the same principle as in the first embodiment. Alternatively, as in the first embodiment, the prediction may be made based on the history data of the angular velocity ω0 (engine rotational speed) up to the present.

  Thereafter, the process proceeds to step 404, in which it is determined whether any of the predicted angular velocities ω1 ′, ω2 ′,..., Ωn ′ is 0 or less. As a result, if it is determined that none of the predicted angular velocities ω1 ′, ω2 ′,..., Ωn ′ is less than or equal to 0, the processing in steps 402 to 404 described above is repeated, and a plurality of timings are input at the next crank pulse input timing. Predict the angular speed ω1 ′, ω2 ′,..., Ωn ′ of each calculation timing up to the previous calculation timing to predict the engine rotation descent trajectory, and any of the predicted angular velocities ω1 ′, ω2 ′,. The process of determining whether or not is 0 or less is repeated.

  By repeating such processing, when it is determined in step 404 that any of the predicted angular velocities ω1 ′, ω2 ′,..., Ωn ′ is 0 or less, the process proceeds to step 405, where the angular velocity ω ′ is determined. The routine immediately ends when it is determined that the TDC immediately before 0 or less is the last TDC in the forward rotation direction.

Also in the third embodiment described above, substantially the same effect as in the first embodiment can be obtained.
In the third embodiment, the engine rotation descent trajectory is predicted for each crank pulse input timing. For example, the engine rotation descent trajectory is predicted for each TDC or every time a predetermined number of crank pulses are input. May be.

  In the first and third embodiments, it is determined whether or not the predicted angular velocity is 0 or less, and it is determined whether or not it is the last TDC in the forward rotation direction. Thus, it may be determined whether or not it is the last TDC in the forward rotation direction based on whether or not the predicted angular velocity is a predetermined value or less.

  The present invention is not limited to a system equipped with a starter 11 that can individually operate the pinion actuator 14 and the motor 12 that rotationally drives the pinion 13, and the pinion actuator and the motor that rotationally drives the pinion are driven simultaneously. The present invention can be applied to a system equipped with a starter.

  In addition, it goes without saying that the present invention can be implemented with various modifications, such as being similarly applicable even when the interval of the crank pulse output from the crank angle sensor 25 is other than 30 ° C.

  DESCRIPTION OF SYMBOLS 11 ... Starter, 12 ... Motor, 13 ... Pinion, 14 ... Pinion actuator, 20 ... ECU (last TDC determination means, control means), 21 ... Engine, 22 ... Crankshaft, 23 ... Ring gear

Claims (5)

In preparation for the next restart, the starter pinion jumps into the ring gear connected to the crankshaft of the engine and engages it in preparation for the next restart during the period when the engine speed when the engine is automatically stopped In the engine automatic stop / start control device,
Last TDC determination means for determining the last TDC in the forward rotation direction during a period in which the engine rotation speed when the engine is automatically stopped decreases;
An engine automatic stop / start control device comprising: control means for determining drive timing of the pinion based on the last TDC in the forward rotation direction determined by the last TDC determination means.   When the engine is automatically stopped, the last TDC determination means rotates the engine at each calculation timing up to the next calculation timing or a plurality of previous calculation timings based on at least the engine rotation speed or angular velocity at a predetermined calculation cycle. The engine automatic stop / start control according to claim 1, wherein the engine rotational descent trajectory is predicted by predicting the speed or angular velocity, and the last TDC in the forward rotation direction is determined based on the predicted engine rotational descent trajectory. apparatus.   When the engine is automatically stopped, the last TDC determination means considers at least one of the loss torque, loss energy, and inertia of the engine at a predetermined calculation cycle until the next calculation timing or a plurality of previous calculation timings. The engine automatic stop / start control apparatus according to claim 2, wherein the engine rotational speed or angular speed at each of the calculation timings is predicted.   When the engine is automatically stopped, the last TDC determination means predicts the engine rotation speed or angular speed at the next calculation timing based on at least the engine rotation speed at a predetermined calculation cycle, and further based on the prediction data The process of predicting the engine rotation speed or angular velocity at the next calculation timing is repeated a plurality of times to predict the engine rotation descent trajectory up to the calculation timing a plurality of times ahead, and forward rotation based on the predicted engine rotation descent trajectory. 2. The engine automatic stop / start control apparatus according to claim 1, wherein the last TDC in the direction is determined.   The last TDC determining means predicts time tTDC until reaching the next TDC, means predicting time t0 rpm until the engine speed reaches 0 [rpm], and reaches the next TDC. The predicted value of the time tTDC until the engine rotational speed reaches 0 [rpm] is compared with the predicted value of the time t0rpm until the last TDC in the forward rotation direction is determined based on the comparison result. The engine automatic stop / start control device according to any one of claims 1 to 4.

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