JP6885269B2 - Control device for automatic transmission - Google Patents

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 flood control supplied to the engaging device based on the engine speed when a shift is changed from a non-traveling range to a traveling range.

Japanese Unexamined Patent Publication No. 10-002409

By the way, as a vehicle equipped with an engine, there is known a vehicle that automatically stops the engine when the vehicle is temporarily stopped while waiting for a traffic light and implements automatic engine stop control for restarting the engine when the vehicle starts. At the time of this restart, the combustion of the engine is not stable immediately after the engine is started, so that 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 the shift is changed from the non-running range to the running range immediately after the engine is started, the engagement device is transferred based on the engine speed in an unstable state. Supply oil pressure will be determined. In this case, a hydraulic pressure deviating from the actually required supply hydraulic pressure is supplied to the engaging device, which may cause an engaging shock and reduce the responsiveness of the engaging device.

The present invention has been made in view of the above circumstances, and is an automatic transmission control device capable of suppressing a decrease in responsiveness of an engaging device while suppressing an engaging shock when the engine is restarted. The purpose is to provide.

The present invention controls an automatic transmission applied to a vehicle that implements 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. The apparatus has a hydraulic control means for controlling the supply hydraulic pressure to the engaging device provided in the automatic transmission based on the engine rotation speed, and the hydraulic control means is used when the engine is restarted after the engine is completely detonated. If the shift range is switched from the non-running range to the running range before the engine speed reaches the target idle speed, after judging that the engine speed is stable at the target idle speed. , It is characterized in that the supply hydraulic pressure is different with respect to the engine speed.

According to the present invention, when the engine is restarted, it is possible to control the oil supply to the engaging device to an appropriate magnitude when the shift is changed from the non-traveling range to the traveling range immediately after the engine is started. ..

FIG. 1 is a skeleton diagram schematically showing a vehicle according to an embodiment. FIG. 2 is a flowchart showing an example of the flood control flow executed when the engine is restarted. FIG. 3 is a flowchart showing a hydraulic control flow at the time of restarting the engine, which is carried out in the first embodiment. FIG. 4 is a flowchart showing a hydraulic control flow at the time of restarting the engine, which is carried out in the second embodiment. FIG. 5 is a flowchart showing a hydraulic control flow at the time of restarting the engine, which is carried out in the third embodiment. FIG. 6 is a time chart showing a vehicle state when the engine is restarted.

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

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 the wheels (not shown) via the torque converter 2 and the automatic transmission 3.

The engine 1 is a power source for a vehicle and is composed of a known internal combustion engine. The operating state of the engine 1 such as the fuel supply amount and the ignition timing is controlled by the ECU 10 described later. This controls the engine torque. Further, the vehicle includes a starter 4 as a starting device for rotating the crankshaft of the engine 1. The starter 4 is driven by electric power and is driven and controlled by the ECU 10. For example, when the engine is started, the ECU 10 starts rotating the crankshaft of the engine 1 by the starter 4, and then injects fuel and ignites the engine 1.

The torque converter 2 includes 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 composed of 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 shifts a plurality of engaging devices by switching between engaging and disengaging. For example, the automatic transmission 3 has a planetary gear mechanism and a plurality of engaging devices, and different gears can be selectively formed by selectively engaging the engaging devices. The plurality of engaging devices are composed of hydraulic friction engaging devices, each of which has a hydraulic actuator, and the engaging force is changed by the hydraulic pressure supplied from the hydraulic control circuit 20 provided in the vehicle to engage with the engaging device. It can be switched between open and open. Further, the plurality of engaging devices include an engaging device capable of putting the automatic transmission 3 in a neutral state by opening. This engaging device is referred to as a clutch C in this embodiment. By engaging the clutch C, the power transmission path between the input shaft 5 and the output shaft 6 is brought into a state where power transmission is possible. The control of the supply hydraulic pressure to the clutch C is performed by the ECU 10 and the hydraulic control circuit 20.

The hydraulic control circuit 20 is a known hydraulic control circuit that uses a mechanical oil pump driven by the engine 1 as a hydraulic supply source, and is a plurality of control valves that regulate the supply hydraulic pressure to the clutch C, and the control hydraulic pressure on the control valves. It is equipped with a plurality of linear solenoids that output the above (none of them are shown). By inputting the oil pressure command signal (instructed pressure) output from the ECU 10 into the oil pressure control circuit 20, the oil supply to the clutch C is controlled based on the instructed pressure. Then, oil is supplied from the hydraulic control circuit 20 to the hydraulic actuator of the clutch C.

Further, the vehicle is 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 by selectively adjusting the shift range such as "P", "R", "N", and "D". The shift ranges "P" and "N" are non-traveling ranges for setting the power transmission path of the automatic transmission 3 in a neutral state in which the power transmission path is cut off. The shift ranges "D" and "R" are traveling ranges for setting the power transmission path of the automatic transmission 3 into a state in which the power transmission path is connected so as 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 device that controls a vehicle, controls an engine 1, and also controls an automatic transmission 3. Signals from various sensors (not shown) mounted on the vehicle are input to the ECU 10. Then, the ECU 10 executes various arithmetic processes based on the signals input from the sensors, and outputs a command signal corresponding to the arithmetic results to the engine 1, the hydraulic control circuit 20, and the like. The various sensors described above include an engine rotation speed sensor that detects the rotation speed of the crank shaft of the engine 1 (engine rotation speed Ne) and the rotation speed of the input shaft 5 (turbine shaft rotation speed: turbine rotation speed Nt). Input rotation speed sensor to detect, output rotation speed sensor to detect the rotation speed of the 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 It includes a brake stroke sensor that detects the amount of depression, a shift sensor that detects the range of the shift lever, and the like.

The control of the engine 1 performed by the ECU 10 includes automatic stop / restart control of the engine 1 in addition to control of the fuel injection amount and the ignition timing. In the automatic stop / 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 due to waiting for a traffic light or the like, the ECU 10 determines that a predetermined automatic stop condition is satisfied and automatically stops the engine 1. When the shift lever is operated during this automatic stop to shift from the D range to the non-traveling range of the N range or the P range, the ECU 10 releases the clutch C. At this time, the oil pressure is released from the hydraulic actuator of the clutch C. Then, when the ECU 10 determines that the predetermined restart condition is satisfied after automatically stopping the engine 1, it outputs a starter control command signal to the starter 4, drives the starter 4 to perform cranking, and causes the engine 1 to operate. Restart. As this restart condition, for example, when the shift range is in the non-driving range while the vehicle is stopped, when the driver detects that the brake pedal is depressed (brake ON) from the state where the brake pedal is not depressed (brake OFF). Can be mentioned. When the engine 1 is restarted, the starter 4 starts rotating the crankshaft of the engine 1 and then starts fuel injection and ignition into the cylinder of the engine 1. Then, the engine 1 is put into an idle state, that is, an autonomous operation state in which the engine speed Ne is maintained at the idle speed by the combustion of the engine 1.

The control of the automatic transmission 3 performed by the ECU 10 includes a gear ratio control for controlling the gear ratio of the automatic transmission 3. In the gear ratio control, clutch control for selectively engaging and disengaging a plurality of engaging devices is performed. When the ECU 10 executes clutch control, it outputs a hydraulic command signal for performing grip change control for forming a predetermined shift stage and a hydraulic command signal for setting the automatic transmission 3 to the neutral state to the hydraulic control circuit 20. To do. Then, the electromagnetic valve operates in response to the oil pressure command signal from the ECU 10, so that the oil pressure supplied to the oil pressure actuator of the clutch C can be adjusted.

Further, the ECU 10 includes a hydraulic control means for controlling the supply hydraulic pressure to the clutch C based on the engine speed. In this flood control means, the shift range is switched from the non-traveling range to the traveling range when the engine 1 is restarted from the state in which the automatic stop / restart control is executed when the vehicle is temporarily stopped and the engine 1 is automatically stopped. In this case, the supply hydraulic pressure to the clutch C can be controlled based on the engine torque.

FIG. 2 is a flowchart showing an example of the flood control flow when the engine is restarted. The control flow shown in FIG. 2 is executed by the ECU 10 when the restart condition of the engine 1 is satisfied and after the engine 1 is completely detonated. The precondition for executing this control flow includes a state in which the engine 1 is returning from the automatic stop state, the vehicle is stopped, and the brake pedal is depressed.

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

If the shift range remains in the non-traveling range after the engine is completely detonated and a negative determination is made in step S1 (step S1: No), no oil is supplied to the clutch C, so this control routine ends.

When the shift range is positively determined in step S1 due to the shift change from the non-traveling range to the traveling range after the engine is completely detonated (step S1: Yes), the ECU 10 is in a state where the combustion of the engine 1 is not stable. It is determined whether or not there is (step S2). The state in which the combustion of the engine 1 is not stable means a state in which the engine speed is not stable at the target idle speed. After the engine is completely detonated, the engine speed overshoots the target idle speed, then drops to the target idle speed, and stabilizes at the target idle speed. Even if the determination is positive in step S1, the vehicle does not start even if the shift is changed to the traveling range because the brake pedal is depressed.

If it is positively determined in step S2 because the combustion of the engine 1 is not stable after the engine is completely detonated (step S2: Yes), the ECU 10 changes the oil supply to the clutch C to the oil pressure A based on the engine torque. Control (step S3). The oil pressure A is the oil pressure set in the idle unstable state. In the process of step S3, the ECU 10 sets the oil pressure A calculated based on the engine torque as the instruction pressure, and outputs the instruction pressure (hydraulic command signal) to the oil pressure control circuit 20. When the process of step S3 is executed, this control routine ends. Although details will be described later, in the process of step S3, the supply oil pressure can be determined to be the oil pressure A based on the engine speed Ne, in addition to the method based on the engine torque.

If it is negatively determined in step S2 because the combustion of the engine 1 is stable after the engine is completely detonated (step S2: No), the ECU 10 determines the oil supply to the clutch C as the oil pressure B based on the engine speed. (Step S4). The oil pressure B is the oil pressure set in the idle stable state. In the process of step S4, the ECU 10 sets the oil pressure B calculated based on the engine speed as the instruction pressure, and outputs the instruction pressure (hydraulic command signal) to the oil pressure control circuit 20. When the process of step S4 is executed, this control routine ends. When the supply oil pressure is determined based on the engine speed Ne in the process of step S3 described above, the oil supply B determined in the process of step S4 makes the supply oil pressure for the engine speed Ne different from that of step S3. Value.

Further, the control flow shown in FIG. 2 described above is repeatedly executed when the engine 1 is restarted. Therefore, when the shift is changed from the non-running range to the running 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 stabilizes, and the combustion of the engine 1 becomes stable. After that, the hydraulic pressure of the clutch C is controlled based on the engine speed. As a result, the supply oil pressure to the clutch C can be switched before and after the combustion of the engine 1 becomes stable. As a result, even in the engine transient state when the engine is restarted, the same level of responsiveness and engagement shock reduction as in the engine stable state can be realized.

(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 restarting. FIG. 3 is a flowchart showing a hydraulic control flow at the time of restarting the engine, which is carried out in the first embodiment. Note that step S11 shown in FIG. 3 is the same as step S1 in FIG. 2, step S13 shown in FIG. 3 is the same as 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 shifts from the non-traveling range to the traveling range after the engine is completely detonated (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 or not the value obtained by subtracting the target engine torque from the current engine torque is larger than the threshold value. This target engine torque is set to the engine torque output from the engine 1 in a state where 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 in an unstable state by using the engine torque after the engine is completely detonated. 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 driving state based on the signals input to the ECU 10 from various sensors. 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 restarting by using the elapsed time from the predetermined starting point after the engine is completely detonated. FIG. 4 is a flowchart showing a hydraulic control flow at the time of restarting the engine, which is carried out in the second embodiment. Note that step S21 shown in FIG. 4 is the same as step S1 in FIG. 2, step S23 shown in FIG. 4 is the same as 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 shifts from the non-traveling range to the traveling range after the engine is completely detonated (step S21: Yes), the timer of the ECU 10 sets a predetermined time (for example, T seconds). It is determined whether or not it has passed (step S22). In the process of step S22, it is determined whether or not a predetermined time (for example, T1 second) has elapsed from the time when it is determined that the engine 1 has completely exploded. Further, since the turbine torque increased when the engine 1 is first detonated decreases after the engine is completely detonated, the ECU 10 determines whether or not the turbine torque is smaller than the threshold value after the engine is completely detonated. 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 becomes smaller than the threshold value. Alternatively, since the engine torque increased when the engine 1 first detonates decreases after the engine is completely detonated, the ECU 10 determines whether or not the engine torque is smaller than the threshold value after the engine is completely detonated. It may be determined whether or not it is before a predetermined time (for example, T3 seconds) elapses from the time point when it is determined that the torque becomes smaller than the threshold value. Alternatively, in the process of step S22, is it before a predetermined time (for example, T4 seconds) elapses from the time when it is detected that the shift operation from the non-travel range to the travel range has been performed in the process of step S21? It may be determined whether or not. Further, the starting point may be the time when the engine 1 starts to rotate, or the starting point may be the time when the first explosion of the engine 1 is determined. Further, the starting point may be a time when it is determined that the restart condition is satisfied, or a time 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 can be determined that the combustion of the engine 1 is in an unstable state by using the elapsed time from a predetermined starting point after the engine is completely detonated. In short, the starting point may be the time when the automatic stop of the engine 1 is completed.

(Example 3)
In the third embodiment, it is determined that the combustion of the engine 1 is not stable at the time of restarting by using the engine speed. FIG. 5 is a flowchart showing a hydraulic control flow at the time of restarting the engine, which is carried out in the third embodiment. Note that step S31 shown in FIG. 5 is the same as step S1 in FIG. 2, step S33 shown in FIG. 5 is the same as 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 shifts from the non-traveling range to the traveling range after the engine is completely detonated (step S31: Yes), whether or not the engine speed of the ECU 10 is larger than the threshold value. (Step S32). In the process of step S32, it may be determined whether or not the value obtained by subtracting the target engine speed from the current engine speed is larger than the threshold value. This target engine speed is set to the target idle speed. According to the third embodiment, it can be determined that the combustion of the engine 1 is not stable by using the engine speed after the engine is completely detonated.

FIG. 6 is a time chart showing a vehicle state when the engine 1 is restarted. First, in the state before restarting the engine 1 (during automatic stop) shown in FIG. 6, the shift range is “N”. Therefore, the oil 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 of the engine 1 is in progress. As shown in FIG. 6, when the restart condition is satisfied, the engine 1 is cranked by the starter 4, so that the engine speed Ne starts to rise from zero (time t1). When the engine speed Ne begins to rise, the first fuel injection and ignition (first explosion) to the engine 1 are performed (time t2). After the initial explosion of the engine 1, the engine torque Te is output, the turbine speed Nt rises, 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 exploded at time t3. After the engine is completely detonated, the engine status flag is switched to the flag F2 indicating that the engine is idling (time t4). Then, the shift range is shifted from the N range (non-running range) to the D range (running range) (time t5). At time t5, the ECU 10 detects that the shift has changed from the non-traveling range to the traveling range, and starts supplying the oil pressure to the clutch C. At the 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, the ECU 10 outputs an instruction pressure P 1} for setting the supply oil pressure Pc to the clutch C to the target oil pressure to the oil pressure control circuit 20. This target oil pressure is the oil pressure A based on the engine torque Te. Further, the supply oil pressure Pc to the clutch C is shown by a broken line in FIG. Further, the ECU 10 performs skort control and outputs the skort instruction pressure P2 to the flood control circuit 20. The actual skort pressure Ps with respect to the indicated skort pressure P ₂ is shown by a alternate long and short dash line in FIG. After that, the engine speed Ne decreases to the target idle speed and stabilizes at the target idle speed (time t6). After time t6, the engine 1 is in an idle stable state (an idle state in which the combustion of the engine 1 is stable). In this way, when the shift change to the traveling range is performed when the engine is restarted, the supply oil pressure to the clutch C is controlled based on the engine torque Te until the combustion of the engine 1 stabilizes (until time t6). To. As a result, the fluctuation (engagement shock) of the front-rear G of the vehicle that 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 and maintained at a predetermined opening degree in a state where the accelerator pedal is not depressed. Further, since the engine 1 is rotating after the 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 shift range is changed from the non-running range to the running range when the engine 1 is restarted and the combustion of the engine 1 is not stable immediately after the engine is started. The oil supply to the clutch C is controlled based on the engine torque. As a result, it is possible to suppress a decrease in the responsiveness of the clutch C while suppressing an engagement shock in the clutch C. Therefore, it is possible to suppress an excess or deficiency of the 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 returning from the automatic engine stop state, the fluctuation of the front-rear acceleration of the vehicle can be reduced, and good driveability can be ensured.

The above-mentioned automatic stop / restart control of the engine 1 is a control called so-called idling stop control, stop-and-start control (S & S control), eco-run control (free-run control), and the above-mentioned vehicle. This can be performed not only when the vehicle is temporarily stopped but also when the vehicle is traveling (for example, when traveling at a high vehicle speed or when decelerating).

Further, the supply oil pressure set at the time of restarting the engine 1 is not limited to the engine torque, and may be controlled based on the engine speed Ne. In this case, the supply oil pressure value determined based on the engine speed Ne is set to a value considering the deviation from the engine torque, and the supply to the engine speed Ne is performed before and after it is judged that the combustion is stable. Switch the oil pressure value. Specifically, when the shift is changed from the non-running range to the running range when the engine is restarted, the supply oil pressure is controlled based on the engine speed Ne after it is judged that the combustion is stable. However, before and after the judgment, the supply oil pressure for the engine speed Ne is determined to be a different value. For example, until it is determined that the combustion of the engine is stable, the supply oil pressure corresponding to the above-mentioned oil pressure A is set with reference to the map showing the correspondence relationship between the engine speed Ne and the oil pressure. The map for setting the flood control A is a map that anticipates that the engine speed Ne and the engine torque deviate immediately after the engine is started due to the unstable combustion. On the other hand, after it is determined that the combustion of the engine 1 is stable, the supply oil pressure corresponding to the above-mentioned oil pressure B is set with reference to the map showing the correspondence relationship between the engine speed Ne and the oil pressure in the normal combustion state. .. That is, before and after it is determined that the combustion is stable, the supply oil pressure is determined by referring to a map in which the correspondence relationship between the engine speed Ne and the oil pressure is different. That is, in a state where combustion is unstable immediately after the engine is started, the map is switched to a map (a map showing the relationship between the engine speed Ne and the oil pressure) in which the deviation between the engine speed Ne and the engine torque is taken into consideration, and the clutch C is switched to. Determine the supply oil pressure. Further, in the transitional period in which the engine speed Ne that overshoots before the combustion stabilizes decreases toward the target idle speed, the engine torque decreases, and as a result, the engine speed Ne decreases. Therefore, when the combustion is unstable immediately after the engine is started, the engine torque deviates in the lower direction with respect to the engine speed Ne as compared with the case where the combustion is stable. Therefore, even if the engine speed is Ne, the supply oil pressure is set lower in the transitional period before the combustion stabilizes than after the combustion stabilizes.

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

Claims (1)

In the control device of an automatic transmission applied to a vehicle that implements automatic engine stop / restart control, the engine is automatically stopped when a predetermined automatic stop condition is satisfied and the engine is restarted when a predetermined restart condition is satisfied.
It has a hydraulic control means for controlling the flood control supplied to the engaging device provided in the automatic transmission based on the engine speed.
The hydraulic control unit, when restarting the engine, when the engine rotational speed at a complete explosion of the engine shift range before the target idle speed is changed from the non-driving range to the driving range is The automatic system is characterized in that the supply oil pressure is different with respect to the engine speed depending on whether it is determined that the predetermined time has elapsed from the predetermined starting point before the predetermined time has elapsed and the case where it has been determined that the predetermined time has elapsed. Transmission control device.

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