JP2019049301A - Automatic transmission control apparatus - Google Patents

Abstract

To suppress deterioration in response of an engagement device while suppressing an engagement shock when restarting an engine.SOLUTION: An automatic transmission control apparatus is applied to a vehicle that executes engine automatic stop and restart control in which the engine is automatically stopped upon establishment of a given automatic stop condition, with the engine restarted upon establishment of a given restart condition. The control apparatus includes hydraulic pressure control means for controlling hydraulic pressure to be supplied to an engagement device disposed in the automatic transmission on the basis of an engine revolution speed. Further, in a case where a shift range is switched from a non-travel range to a travel range before an engine revolution speed reaches a target idling revolution speed after a complete explosion of the engine when it is restarted (Yes for step S1), the hydraulic pressure control means differentiates the supplied hydraulic pressure before and after determining the engine revolution speed is stable at the target idling revolution speed (steps S3, S4).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control device for an automatic transmission.

  Patent Document 1 discloses a control device for an automatic transmission that increases or decreases the hydraulic pressure supplied to the engagement device based on the engine speed when a shift is made from the non-traveling range to the traveling range.

Japanese Patent Application Laid-Open No. 10-002409

  By the way, as a vehicle equipped with an engine, one that carries out an engine automatic stop control that automatically stops the engine when it temporarily stops while waiting for a traffic light and restarts the engine when starting is known. At this restart, since the combustion of the engine is not stable immediately after starting the engine, the engine speed may overshoot with respect to the target idle speed.

  When the configuration described in Patent Document 1 is applied to automatic engine stop control, when a shift is made from the non-traveling range to the traveling range immediately after the start of the engine, the engagement device is selected based on the unstable engine rotation speed. Supply hydraulic pressure will be determined. In this case, the hydraulic pressure deviated from the actually required supply hydraulic pressure is supplied to the engagement device, an engagement shock occurs, and the responsiveness of the engagement device may be reduced.

  The present invention has been made in view of the above circumstances, and provides a control device of an automatic transmission that can suppress the responsiveness deterioration of the engagement device while suppressing the engagement shock when restarting the engine. Intended to be provided.

  The present invention controls an automatic transmission applied to a vehicle that implements automatic engine stop and restart control that automatically stops the engine when a predetermined automatic stop condition is met and restarts the engine when a predetermined restart condition is met. The device includes hydraulic control means for controlling the hydraulic pressure supplied to the engagement device provided in the automatic transmission based on the engine rotational speed, and the hydraulic control means is used to restart the engine after the complete explosion of the engine. If the shift range is switched from the non-traveling range to the travel range before the engine speed reaches the target idle speed, after it is determined that the engine speed is determined to be stable at the target idle speed The present invention is characterized in that the supplied oil pressure is different with respect to the engine speed.

  According to the present invention, when the engine is restarted, the hydraulic pressure supplied to the engagement device can be controlled to an appropriate level when the shift from the non-traveling range to the traveling range is made immediately after the start of the engine. .

FIG. 1 is a skeleton diagram schematically showing a vehicle in the embodiment. FIG. 2 is a flow chart showing an example of a hydraulic pressure control flow implemented at engine restart. FIG. 3 is a flow chart showing a hydraulic pressure control flow at engine restart implemented in the first embodiment. FIG. 4 is a flow chart showing a hydraulic control flow at engine restart implemented in the second embodiment. FIG. 5 is a flowchart showing a hydraulic control flow at engine restart implemented in the third embodiment. FIG. 6 is a time chart showing a vehicle state at the time of restarting the engine.

  Hereinafter, with reference to the drawings, a control device of an automatic transmission according to an embodiment of the present invention will be specifically described.

  FIG. 1 is a skeleton diagram schematically showing a target vehicle in the embodiment. The vehicle includes an engine 1, a torque converter 2, and an automatic transmission 3. The power output from the engine 1 is transmitted to wheels (not shown) via the torque converter 2 and the automatic transmission 3.

  The engine 1 is a power source of a vehicle, and is configured by a known internal combustion engine. The operation state of the engine 1 such as the fuel supply amount and the ignition timing is controlled by the ECU 10 described later. Thereby, the engine torque is controlled. The vehicle also includes a starter 4 as a starting device for rotating a crankshaft of the engine 1. The starter 4 is driven by electric power and is drive-controlled by the ECU 10. For example, when the engine is started, the ECU 10 starts to rotate the crankshaft of the engine 1 by the starter 4 and then performs fuel injection and ignition to the engine 1.

  The torque converter 2 has a turbine runner 2a that rotates integrally with the crankshaft of the engine 1, a turbine runner 2b that rotates integrally with the turbine shaft, and a lockup clutch 2c. The turbine shaft of the torque converter 2 rotates integrally with the input shaft 5 of the automatic transmission 3.

  The automatic transmission 3 is configured by a known automatic transmission that shifts the power input from the input shaft 5 and outputs the power from the output shaft 6. The automatic transmission 3 is a stepped transmission that implements gear change by switching between engagement and release for a plurality of engagement devices. For example, the automatic transmission 3 has a planetary gear mechanism and a plurality of engagement devices, and different gear stages can be selectively formed by selectively engaging the engagement devices. Each of the plurality of engagement devices is constituted by a hydraulic friction engagement device having a hydraulic actuator, and the engagement force is changed by the hydraulic pressure supplied from the hydraulic control circuit 20 provided in the vehicle. It is switched to open. Furthermore, the plurality of engagement devices include an engagement device capable of bringing the automatic transmission 3 into a neutral state by opening. This engagement device is referred to as a clutch C in the present embodiment. When the clutch C is engaged, the power transmission path between the input shaft 5 and the output shaft 6 is in a state capable of power transmission. Control of the hydraulic pressure supplied to the clutch C is performed by the ECU 10 and the hydraulic control circuit 20.

  The hydraulic control circuit 20 is a well-known hydraulic control circuit using a mechanical oil pump driven by the engine 1 as a hydraulic pressure supply source, and a plurality of control valves for adjusting the hydraulic pressure supplied to the clutch C and control hydraulic pressure for the control valves. And a plurality of linear solenoids (not shown). The hydraulic pressure command signal (instruction pressure) output from the ECU 10 is input to the hydraulic control circuit 20, whereby the hydraulic pressure supplied to the clutch C is controlled based on the instruction pressure. Then, the hydraulic pressure is supplied from the hydraulic control circuit 20 to the hydraulic actuator of the clutch C.

  The vehicle is also provided with a shift lever (not shown) operated by the driver to switch the state of power transmission in the automatic transmission 3. The shift lever is manually operated selectively in a shift range such as "P", "R", "N", "D". The shift ranges “P” and “N” are non-traveling ranges for achieving the neutral state in which the power transmission path of the automatic transmission 3 is shut off. The shift ranges “D” and “R” are travel ranges for setting the power transmission path of the automatic transmission 3 to be able to transmit power. In the non-traveling range (P range, N range), the clutch C is released, and in the traveling range (D range, R range), the clutch C is engaged.

  The ECU 10 is an electronic control unit that controls a vehicle, and controls the engine 1 and controls the automatic transmission 3. Signals from various sensors (not shown) mounted on the vehicle are input to the ECU 10. Then, the ECU 10 performs various arithmetic processing based on the signal input from the sensor, and outputs a command signal corresponding to the calculation result to the engine 1, the hydraulic control circuit 20, and the like. The various sensors described above include an engine speed sensor for detecting the speed of the crankshaft of the engine 1 (engine speed Ne), the speed of the input shaft 5 (speed of the turbine shaft: turbine speed Nt) Input rotational speed sensor to detect, output rotational speed sensor to detect the rotational speed of output shaft 6, vehicle speed sensor to detect the vehicle speed, accelerator opening sensor to detect the amount of depression of the accelerator pedal (accelerator opening), brake pedal A brake stroke sensor that detects the amount of depression, a shift sensor that detects the range of the shift lever, and the like are included.

  The control of the engine 1 implemented by the ECU 10 includes the automatic stop / restart control of the engine 1 in addition to the control of the fuel injection amount and the ignition timing. In automatic stop and restart control, the engine 1 is automatically stopped when a predetermined automatic stop condition is satisfied, and the engine 1 is automatically restarted when a predetermined restart condition is satisfied. For example, when the vehicle temporarily stops while waiting for a signal or the like, the ECU 10 determines that the predetermined automatic stop condition is satisfied, and automatically stops the engine 1. When the shift lever is operated during this automatic stop and the shift is changed from the D range to the non-traveling range of the N range or the P range, the ECU 10 opens the clutch C. At this time, the hydraulic pressure is removed from the hydraulic actuator of the clutch C. Then, when it is determined that the predetermined restart condition is satisfied after the engine 10 is automatically stopped, the ECU 10 outputs a starter control command signal to the starter 4 to drive the starter 4 to perform cranking and perform the engine 1 To restart. As the restart condition, for example, when the shift range is the non-traveling range while the vehicle is stopped, when the driver's depression of the brake pedal (brake on) is detected from the state where the brake pedal is not depressed (brake off) It can be mentioned. When the engine 1 is restarted, fuel supply to the cylinders of the engine 1 and ignition are started after the starter 4 starts rotating the crankshaft of the engine 1. Then, the engine 1 is in an idle state, that is, in a self-sustaining state in which the engine speed Ne is maintained at the idle speed by the combustion of the engine 1.

  Control of the automatic transmission 3 implemented by the ECU 10 includes transmission ratio control for controlling the transmission ratio of the automatic transmission 3. In transmission ratio control, clutch control is performed to selectively engage and release a plurality of engagement devices. When executing the clutch control, the ECU 10 outputs, to the hydraulic control circuit 20, a hydraulic pressure command signal for performing the grip change control for forming a predetermined shift speed, and a hydraulic pressure command signal for setting the automatic transmission 3 in the neutral state. Do. The hydraulic pressure supplied to the hydraulic actuator of the clutch C can be adjusted by operating the solenoid valve in accordance with the hydraulic pressure command signal from the ECU 10.

  Further, the ECU 10 includes hydraulic control means for controlling the hydraulic pressure supplied to the clutch C based on the engine speed. This hydraulic pressure control means switches the shift range from the non-traveling range to the traveling range when restarting the engine 1 from a state where the automatic stop / restart control is performed and the engine 1 is automatically stopped when the vehicle temporarily stops. In this case, the hydraulic pressure supplied to the clutch C can be controlled based on the engine torque.

  FIG. 2 is a flowchart showing an example of a hydraulic control flow at engine restart. The control flow shown in FIG. 2 is implemented by the ECU 10 after the engine 1 is completely detoned when the restart condition of the engine 1 is satisfied. In addition, the precondition on which this control flow is implemented includes the state in which the brake pedal is depressed while the vehicle is stopped while the engine 1 is returning from the automatic stop state.

  At the time of engine restart, the ECU 10 determines whether or not the shift range is shifted from the non-traveling range to the traveling range after the engine 1 is completely detonated (step S1). In step S1, it is determined based on a signal input from the shift sensor to the ECU 10 whether or not it is detected that a shift change has been made from the N range or P range to the D range or R range.

  If the shift range is determined to be a non-traveling range after the complete explosion of the engine and a negative determination is made in step S1 (step S1: No), the hydraulic pressure is not supplied to the clutch C, and this control routine ends.

  If the shift range is shifted from the non-traveling range to the traveling range after the complete explosion of the engine and a positive determination is made in step S1 (step S1: Yes), the ECU 10 determines that the combustion of the engine 1 is not stable. It is determined whether there is any (step S2). The state where the combustion of the engine 1 is not stable means the state where the engine speed is not stable at the target idle speed. After the complete explosion of the engine, the engine rotational speed overshoots the target idle rotational speed and then decreases to the target idle rotational speed and stabilizes at the target idle rotational speed. Even when the determination in step S1 is affirmative, the vehicle does not start even if the vehicle is shifted to the travel range because the brake pedal is depressed.

  If the determination in step S2 is affirmative because the combustion of the engine 1 is not stable after the complete explosion of the engine (step S2: Yes), the ECU 10 changes the oil pressure supplied to the clutch C to the oil pressure A based on the engine torque. It controls (step S3). The hydraulic pressure A is a hydraulic pressure set to an idle unstable state. In the process of step S3, the ECU 10 sets the hydraulic pressure A calculated based on the engine torque as the command pressure, and outputs the command pressure (hydraulic command signal) to the hydraulic control circuit 20. When the process of step S3 is performed, this control routine ends. Although the details will be described later, in the process of step S3, it is also possible to determine the supplied hydraulic pressure as the hydraulic pressure A based on the engine rotational speed Ne, separately from the method based on the engine torque.

  If the determination in step S2 is negative because the combustion of the engine 1 is stable after the complete explosion of the engine (step S2: No), the ECU 10 calculates the hydraulic pressure supplied to the clutch C based on the engine speed B (Step S4). The hydraulic pressure B is a hydraulic pressure set to an idle stable state. In the process of step S4, the ECU 10 sets the hydraulic pressure B calculated based on the engine rotation speed to the command pressure, and outputs the command pressure (hydraulic command signal) to the hydraulic control circuit 20. When the process of step S4 is performed, this control routine ends. When the supplied oil pressure is determined based on the engine rotational speed Ne in the process of step S3 described above, the hydraulic pressure B determined in the process of step S4 changes the supplied hydraulic pressure with respect to the engine rotational speed Ne from step S3. Value.

  Further, the control flow shown in FIG. 2 described above is repeatedly performed when the engine 1 is restarted. Therefore, when a shift is made from the non-traveling range to the traveling range when the engine 1 is restarted, the hydraulic pressure of the clutch C is controlled based on the engine torque until the combustion of the engine 1 is stabilized, and the combustion of the engine 1 is stabilized. After that, the hydraulic pressure of the clutch C is controlled based on the engine speed. Thus, the hydraulic pressure supplied to the clutch C can be switched before and after the combustion of the engine 1 is stabilized. As a result, even in the engine transient state at the time of engine restart, it is possible to realize responsiveness and engagement shock reduction at the same level as in the engine steady state.

(Example)
Here, a specific processing example of step S2 shown in FIG. 2 described above will be described as Examples 1 to 3.

Example 1
In the first embodiment, the engine torque is used to determine that the combustion of the engine 1 is not stable at the time of restart. FIG. 3 is a flow chart showing a hydraulic pressure control flow at engine restart implemented in the first embodiment. Step S11 shown in FIG. 3 is the same as step S1 in FIG. 2, step S13 shown in FIG. 3 is step S3 in FIG. 2, and step S14 shown in FIG. 3 is the same as step S4 in FIG. Is omitted.

  As shown in FIG. 3, in the first embodiment, when the shift range is shifted from the non-traveling range to the traveling range after the complete explosion of the engine (step S11: Yes), the ECU 10 determines whether the engine torque is larger than the threshold value. Is determined (step S12). In the process of step S12, it may be determined whether a value obtained by subtracting the target engine torque from the current engine torque is larger than a threshold. The target engine torque is set to the engine torque output from the engine 1 when the engine speed is stable at the target idle speed (idle stable state). According to the first embodiment, it can be determined that the combustion of the engine 1 is not stable using the engine torque after the complete explosion of the engine. The engine torque used in the process of step S12 is a value (estimated engine torque) obtained by estimating the engine torque output by the ECU 10 in the current engine drive state based on the signals input from the various sensors to the ECU 10. This engine torque estimation method may be a known calculation method.

(Example 2)
In the second embodiment, it is determined that the combustion of the engine 1 is not stable at the time of restart, using the elapsed time from the predetermined starting point after the complete explosion of the engine. FIG. 4 is a flow chart showing a hydraulic control flow at engine restart implemented in the second embodiment. Step S21 shown in FIG. 4 is the same as step S1 in FIG. 2, step S23 shown in FIG. 4 is step S3 in FIG. 2, and step S24 shown in FIG. 4 is the same as step S4 in FIG. Is omitted.

  As shown in FIG. 4, in the second embodiment, when the shift range is shifted from the non-traveling range to the traveling range after the complete explosion of the engine (step S21: Yes), the ECU 10 determines that the timer has a predetermined time (for example, T seconds). It is judged whether it is before it passes (step S22). In the process of step S22, it is determined whether or not a predetermined time (for example, T1 second) has passed before a point at which it is determined that the engine 1 has completely detonated is a starting point. Further, since the turbine torque increased when the engine 1 is initially detonated decreases after the complete explosion of the engine, the ECU 10 determines whether the turbine torque is smaller than the threshold after the complete explosion of the engine, and in the process of step S22, the turbine It may be determined whether or not it is before a predetermined time (for example, T2 seconds) elapses from the time point when it is determined that the torque is smaller than the threshold value. Alternatively, since the engine torque increased when the engine 1 first detonates decreases after the complete explosion of the engine, the ECU 10 determines whether the engine torque is smaller than the threshold after the complete explosion of the engine, and in the process of step S22, the engine It may be determined whether or not a predetermined time (e.g., T3 seconds) has passed before a point at which it is determined that the torque has become smaller than the threshold value. Alternatively, in the process of step S22, whether or not a predetermined time (for example, T4 seconds) has elapsed from when the shift operation from the non-traveling range to the traveling range is detected in the process of step S21 is detected as a starting point It may be determined whether or not. Further, the time when the engine 1 starts to rotate may be used as the starting point, and the time when the first explosion of the engine 1 is determined may be used as the starting point. Furthermore, the starting point may be determined when it is determined that the restart condition is satisfied, or may be started when the engine state flag is switched from the flag in the start request to the idle state flag after the restart condition is satisfied. According to the second embodiment, it is possible to determine that the combustion of the engine 1 is not stable using the elapsed time from the predetermined starting point after the complete explosion of the engine. In short, the point at which the automatic stop of the engine 1 ends may be taken as the starting point.

(Example 3)
In the third embodiment, it is determined using the engine speed that the combustion of the engine 1 is not stable at the time of restart. FIG. 5 is a flowchart showing a hydraulic control flow at engine restart implemented in the third embodiment. Step S31 shown in FIG. 5 is the same as step S1 in FIG. 2, step S33 shown in FIG. 5 is step S3 in FIG. 2, and step S34 shown in FIG. 5 is the same as step S4 in FIG. Is omitted.

  As shown in FIG. 5, in the third embodiment, when the shift range is shifted from the non-traveling range to the traveling range after the complete explosion of the engine (step S31: Yes), the ECU 10 determines whether the engine speed is larger than the threshold value. It is determined (step S32). In the process of step S32, it may be determined whether the value obtained by subtracting the target engine speed from the current engine speed is larger than a threshold. The target engine speed is set to a target idle speed. According to the third embodiment, it can be determined that the combustion of the engine 1 is not stable using the engine speed after the complete explosion of the engine.

FIG. 6 is a time chart showing a vehicle state when the engine 1 is restarted. First, in the state before restart of the engine 1 shown in FIG. 6 (during automatic stop), the shift range is “N”. Therefore, the hydraulic pressure of the clutch C is zero. Then, when the predetermined restart condition is satisfied, the engine state flag becomes the flag F1 indicating that the start request for the engine 1 is being made. As shown in FIG. 6, when the restart condition is satisfied, cranking of the engine 1 by the starter 4 is performed, so the engine rotational speed Ne starts to rise from zero (time t1). When the engine speed Ne starts to rise, the first fuel injection and ignition (first explosion) to the engine 1 are performed (time t2). After the first explosion of the engine 1, the engine torque Te is output, the turbine rotational speed Nt is increased, and the turbine torque Tt amplified by the torque converter 2 is transmitted to the turbine shaft. Then, the engine 1 is completely detonated (time t3). The ECU 10 can determine that the engine 1 has completely detonated at time t3. After the complete explosion of the engine, the engine state flag is switched to the flag F2 indicating that the engine is idling (time t4). Then, the shift range is shifted from N range (non-traveling range) to D range (traveling range) (time t5). At time t5, the ECU 10 detects the shift change from the non-traveling range to the traveling range, and starts hydraulic pressure supply to the clutch C. At time t5 shown in FIG. 6, a positive determination is made in step S2 shown in FIG. 2 described above, and it is determined that the combustion of the engine 1 is not stable. Therefore, ECU 10 outputs the command pressure _{P 1} to a supply oil pressure Pc of the clutch C to the target hydraulic pressure to the hydraulic control circuit 20. This target hydraulic pressure is hydraulic pressure A based on the engine torque Te. Further, the oil pressure Pc supplied to the clutch C is indicated by a broken line in FIG. Further, the ECU 10 executes the squat control and outputs the squat command pressure P2 to the hydraulic control circuit 20. Its squat command pressure P squat actual pressure Ps for ₂ shown in FIG. 6 by a dashed line. Thereafter, the engine speed Ne decreases to the target idle speed, and is stabilized at the target idle speed (time t6). After time t6, the engine 1 is in the idle stable state (an idle state in which the combustion of the engine 1 is stable). Thus, when a shift change to the travel range is performed at engine restart, the hydraulic pressure supplied to the clutch C is controlled based on the engine torque Te until the combustion of the engine 1 is stabilized (up to time t6). Ru. Thereby, the fluctuation (engagement shock) of the back and forth G of the vehicle which occurs when the clutch C is engaged is reduced. The throttle opening degree shown in FIG. 6 indicates that the electrically driven throttle valve is opened at a predetermined opening degree and maintained in a state where the accelerator pedal is not depressed. In addition, since the engine 1 is rotating after time t1, the oil discharged from the mechanical oil pump can be supplied to the hydraulic actuator of the clutch C.

  As described above, according to the present embodiment, when the engine 1 restarts, the shift range changes from the non-traveling range to the traveling range in a state where the combustion of the engine 1 is not stable immediately after the engine start. The hydraulic pressure supplied to the clutch C is controlled based on the engine torque. As a result, it is possible to suppress the decrease in responsiveness of the clutch C while suppressing the engagement shock of the clutch C. Therefore, it is possible to suppress excessive or insufficient engagement hydraulic pressure with respect to the input to the automatic transmission 3. As a result, even when the combustion of the engine 1 is not stable after the return from the engine automatic stop state, the fluctuation of the longitudinal acceleration of the vehicle can be reduced, and good drag can be secured.

  The above-described automatic stop and restart control of the engine 1 is control referred to as so-called idling stop control, stop and start control (S & S control), eco-run control (free-run control), etc. The present invention can be implemented not only when temporarily stopping, but also while the vehicle is traveling (for example, when traveling at high vehicle speeds or during deceleration).

  Further, the supplied oil pressure set at the time of restarting the engine 1 may be controlled based on the engine rotational speed Ne as well as the engine torque. In this case, the supply hydraulic pressure value determined based on the engine rotational speed Ne is set to a value taking into account the deviation from the engine torque, and supply of the engine rotational speed Ne before and after determining that the combustion is stable. Switch the hydraulic pressure value. Specifically, when a shift is made from the non-traveling range to the traveling range at the time of engine restart, the supply hydraulic pressure is controlled based on the engine speed Ne after it is determined that the combustion is stable. However, before and after the determination, the supplied oil pressure with respect to the engine speed Ne is determined to be different values. For example, until it is determined that the combustion of the engine is stable, the supply hydraulic pressure corresponding to the above-described hydraulic pressure A is set with reference to the map showing the correspondence between the engine rotational speed Ne and the hydraulic pressure. The map for setting the hydraulic pressure A is a map that anticipates that the engine rotation speed Ne and the engine torque will be deviated immediately after the start of the engine due to unstable combustion. On the other hand, after determining that the combustion of the engine 1 is stable, the supply hydraulic pressure corresponding to the hydraulic pressure B described above is set with reference to the map showing the correspondence between the engine speed Ne and the hydraulic pressure in the normal combustion state. . That is, before and after determining that the combustion is stable, the supplied hydraulic pressure is determined with reference to a map in which the correspondence between the engine rotational speed Ne and the hydraulic pressure is different. That is, in a state where combustion is unstable immediately after engine start, switching to a map (map showing the relationship between engine rotational speed Ne and hydraulic pressure) in which deviation between engine rotational speed Ne and engine torque is considered is switched to clutch C. Determine the supply hydraulic pressure. Furthermore, during a transition period in which the engine rotational speed Ne overshooted before combustion stabilization decreases toward the target idle rotational speed, the engine torque decreases, and as a result, the engine rotational speed Ne decreases. Therefore, when the combustion is unstable immediately after the start of the engine, the engine torque deviates in a direction lower than the engine rotational speed Ne as compared with the case where the combustion is stable. Therefore, even at the same engine rotational speed Ne, in the transition period before the combustion is stabilized, the supplied oil pressure is set lower than that after the combustion is stabilized.

1 engine 3 automatic transmission 4 starter 10 ECU
C clutch (engagement device)

Claims (1)

In a control device of an automatic transmission applied to a vehicle that executes automatic engine stop / restart control that automatically stops the engine when a predetermined automatic stop condition is satisfied and restarts the engine when a predetermined restart condition is satisfied.
It has hydraulic control means for controlling the hydraulic pressure supplied to the engagement device provided in the automatic transmission based on the engine speed,
The hydraulic control means is configured to restart the engine when the shift range is switched from the non-traveling range to the traveling range after the complete explosion of the engine and before the engine speed reaches the target idle speed. A control device for an automatic transmission, wherein the supplied hydraulic pressure is made different with respect to the engine rotational speed after it is judged that the rotational speed is stable at the target idle rotational speed.

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