JP5351085B2 - Control device for automatic transmission for vehicle - Google Patents

Description

  Techniques relating to a control device for an automatic transmission mounted on a vehicle are disclosed below.

  2. Description of the Related Art In recent years, an automatic transmission for a vehicle in which a shift stage is configured using a plurality of planetary gears and friction engagement elements is known. The automatic transmission selectively engages and disengages the frictional engagement elements by hydraulic control using an electromagnetic valve or the like to fasten appropriate frictional engagement elements, and executes a shift according to the combination of the fastening elements. A CVT (Continuously Variable Transmission) equipped with such an automatic transmission as an auxiliary transmission has been developed and put into practical use. The CVT with a sub-transmission is provided with a sub-transmission that executes, for example, a two-speed forward shift and a forward-reverse switching by controlling the friction engagement element on the output-side secondary pulley.

  In this type of automatic transmission, the possibility of an unnecessary interlock state occurring due to malfunction of the electromagnetic valve is not zero. For example, a fail-safe technique disclosed in Patent Document 1 has been proposed. Further, recently, as disclosed in Patent Documents 2, 3, and 4 in the above automatic transmission, it has been proposed to interlock a predetermined friction engagement element when the vehicle is stopped and use it as an assist for a brake. However, even in this case, the interlock may not be released at the start due to the malfunction of the solenoid valve. Therefore, it is preferable that there is a fail-safe process here.

Japanese Patent Laid-Open No. 2007-092832 JP 2009-144898 A JP 2010-006326 A JP 2010-014168 A

As described above, when an unexpected interlock state occurs, the automatic transmission having the fail-safe function specifies a fastening element that is in the interlock state and executes control for releasing the fastening element. At this time, if it is possible to see from the running state of the vehicle, it is easier to release the fastening element and the load on the device is less when the vehicle is decelerated to the slow speed or stopped state.
The present invention proposes a control device for a vehicle automatic transmission in view of this point.

A control device proposed for the above-described problem is a control device for an automatic transmission for a vehicle that selectively engages a plurality of friction engagement elements by hydraulic pressure and switches a gear position.
An interlock detection means for detecting an interlock state of the fastening elements fastened among the friction engagement elements;
Vehicle state detection means for detecting a vehicle state including at least the vehicle speed and the accelerator opening ;
A torque down control means for determining at least a vehicle speed detected by the vehicle state detection means when the interlock detection means detects an interlock state, and reducing an engine torque when the vehicle speed is equal to or lower than a specified vehicle speed;
It is configured to include a,
The torque-down control means compares the accelerator opening detected by the vehicle state detection means with the specified accelerator opening, and as a result, if it is equal to or less than the specified accelerator opening, a rapid decrease rate is obtained and exceeds the specified accelerator opening. Is a slow decline rate.

The control device for an automatic transmission for a vehicle according to the above proposal executes engine torque reduction according to the vehicle speed and the accelerator opening degree when detecting the interlock state. Since the vehicle is decelerated by the action of the engine brake caused by the engine torque reduction, the fastening element can be easily released.

The figure which showed embodiment of the automatic transmission for vehicles. The flowchart which showed the flow of the torque reduction process which the control apparatus of the automatic transmission for vehicles shown in FIG. 1 performs. FIG. 3 is a time chart of target shift speed, vehicle speed, torque, and accelerator opening when the torque down process shown in FIG. 2 is executed. The flowchart which showed the example of a subroutine of the forced torque down control in FIG. FIG. 5 is a time chart of a target shift speed, vehicle speed, torque, and accelerator opening when the forced torque down control shown in FIG. 4 is executed. The flowchart which showed the other example of a subroutine of the forced torque down control in FIG. The flowchart which showed the other example of a subroutine of the forced torque down control in FIG. FIG. 8 is a time chart of target shift speed, vehicle speed, torque, reduction amount instruction value, and accelerator opening when the forced torque down control shown in FIG. 7 is executed. The flowchart which showed the other example of a subroutine of the forced torque down control in FIG. FIG. 10 is a time chart of a target shift speed, vehicle speed, torque, reduction amount instruction value, and accelerator opening when the forced torque down control shown in FIG. 9 is executed.

FIG. 1 shows an outline of a main part of a vehicle equipped with a CVT with a sub-transmission as an example of an automatic transmission. In addition to the CVT with a sub-transmission, the present invention can be applied to a stepped automatic transmission with so-called clutch-to-clutch control.
The output of the engine 1 is transmitted to the automatic transmission 3 via the torque converter 2. In the automatic transmission 3, the output of the torque converter 2 is transmitted to the primary pulley 3a, and is transmitted from the wound belt 3b to the secondary pulley 3c. The output of the secondary pulley 3c is transmitted from the reduction gear to the drive wheel 4 via the auxiliary transmission 3d.

  The sub-transmission 3d is configured by using a plurality of planetary gears and friction engagement elements to form a shift stage. In this embodiment, the sub-transmission 3d has functions of shifting forward and backward (first speed, second speed) and forward / reverse switching. Have. As described in the above-mentioned patent document, the friction engagement element is a clutch that is intermittently engaged by hydraulic control using a solenoid valve. The friction engagement element is selectively engaged by hydraulic pressure, and the gear position is switched by a combination of the engagement elements. Change. By connecting the secondary forward gear 3d to the secondary pulley 3c, the gear ratio range is increased.

  A control device 10 that controls the automatic transmission 3 communicates with an ECU (Electronic Control Unit) 11 and a car navigation system (hereinafter referred to as a car navigation system) 12 of the engine 1 via a CAN (Controller Area Network) or the like. Navigation information is acquired from the car navigation system 12. Then, based on the accelerator opening (or throttle opening), the rotational speed of the engine 1, the torque, the vehicle speed, and the like detected as the vehicle state information, the control device 10 shifts the pulleys 3a and 3c and the sub-transmission 3d. Control. Further, the control device 10 functions as an interlock detection unit, a vehicle state detection unit, and a torque down control unit, which will be described later, according to a built-in program. When the interlock state occurs in the auxiliary transmission 3d, the torque reduction for the engine 1 is performed. Execute the process. Furthermore, when an interlock state occurs, the control device 10 specifies a fastening element that is in the interlock state, and executes a release process. The interlock state detected by the control device 10 functioning as the interlock detection means is, for example, that the fastening element that has been fastened for brake assist when the vehicle is stopped cannot be released when starting due to malfunction of the solenoid valve. In this state, it is not possible to switch to the next gear position.

  Hereinafter, the torque down process executed in the control device 10 will be described with reference to the flowchart of FIG. In the following description, it is assumed that the frictional engagement element constituting the first speed gear stage is fastened in the stopped sub-transmission 3d, and the first speed fastening element is in the interlock state. The case where the vehicle is decelerated from this state with the accelerator ON will be described as an example.

  The control device 10 that starts in response to the ignition switch ON or the accelerator ON and executes a function as an interlock detection means monitors whether or not an interlock state occurs in the auxiliary transmission 3d in step S1. This interlock detection can be detected by using a hydraulic switch / hydraulic sensor related to the operation of the friction engagement element, if there is a value. Alternatively, in the case of the sensorless system, the interlock state can be detected from an operation in which the torque of the engine 1 exceeding the torque capacity of the fastening element in the interlock state is applied and the fastening element is dragged.

  In step S2, the control device 10 that has detected the interlock state in step S1 determines that the interlock state has occurred on the warning light, buzzer, synthesized voice, or car navigation screen provided on the instrument panel or the like. Notify And the control apparatus 10 performs the function as a vehicle state detection means in step S3, and detects the vehicle speed of the vehicle state information acquired from ECU11. Subsequently, the control device 10 executes a function as torque reduction control means, and determines whether or not the detected vehicle speed is equal to or less than a specified vehicle speed. As an example, the specified vehicle speed is set to 10 km / h as a threshold value, which does not interfere with deceleration. If the control device 10 determines that the specified vehicle speed is exceeded in step S3, the control device 10 proceeds to step S4 and executes the fail-safe process as described in the above-mentioned patent document to keep the vehicle in a travelable state. For example, the fail-safe process is executed by shutting off the supply pressure to the interlocked fastening element by the fail-safe valve provided in the electromagnetic valve.

  The control device 10 that has determined that the vehicle speed is equal to or less than the specified vehicle speed in step S3 executes a function as a torque-down control unit in step S5 and instructs the ECU 11 to forcibly reduce the torque of the engine 1 at a specified decrease rate. The specified reduction rate (torque value to be reduced per hour) at this time is preferably a value that does not lead to an extreme sudden stop due to the engine brake action due to torque reduction, and after detecting the current gear position and interlock state Can be suitably calculated based on the elapsed time, the rotational speed of the engine 1 obtained from the vehicle state information, torque, vehicle speed, and the like. The rate of decrease varies according to the current situation and vehicle type, such as a temporary decrease in torque with a constant ramp (ramp), a stepwise decrease, and an increase or decrease in the degree of decrease. . It should be noted that a stop lamp (brake lamp) or a hazard lamp may be lit to inform the subsequent vehicle that the vehicle is decelerating during this deceleration. Further, if a rear sensor is mounted on the vehicle, when the sensor detects the approach of the succeeding vehicle, control for reducing the engine brake action by devising the torque reduction rate may be executed.

  In step S6, the control device 10 that has started the forced torque down control in step S5 releases the fastening element that is in the interlock state. That is, as described in the above-mentioned patent document, an interlocked fastening element is specified, and an instruction is issued to each part so that the fastening element is released by switching an oil passage with respect to the fastening element. Then, in step S7, the control device 10 determines whether the release is completed. If the release is completed and the interlock state is successfully released, the control device 10 releases the interlock state notification in step S8, and further cancels the forced torque down control in step S9, thereby detecting the interlock state. Return to step S1. Thereafter, normal shift control is executed in accordance with the driver's accelerator work.

FIG. 3A shows a time chart of the shift speed, the vehicle speed, the torque of the engine 1, and the accelerator opening degree related to the processing so far.
When the accelerator is depressed for departure, the accelerator opening gradually increases, and accordingly, the torque of the engine 1 increases and the vehicle speed also increases. However, as described above, an interlock state has occurred in the first-speed engagement element, and even if an attempt is made to shift up to the second speed due to an increase in the vehicle speed, the engagement element constituting the first speed is not released, and at a certain point in time, A lock state is detected. Torque down is executed by detecting the interlock state, and the torque starts down at a specified rate of decrease (arrow Tramp). When the driver turns off the accelerator by notifying the interlock state, the accelerator opening shifts to closing (arrow Aramp). As the torque is reduced, the vehicle speed decreases due to the action of the engine brake (arrow Sramp). When the vehicle speed drops to a speed suitable for releasing the first-speed engagement element, or when the vehicle stops, the first-speed engagement element is released. The Thus, when the first speed engagement element is released, the torque reduction is released and the friction engagement element constituting the second speed is engaged. When the accelerator is stepped on by releasing the interlock state and the accelerator opening is opened, the torque is increased and traveling is performed by the second-speed engagement element. The release of the interlock can be notified to the driver by a warning light, a buzzer, or synthesized voice.

  In the term chart shown in FIG. 3A, if the accelerator is not returned at the time of detecting the interlock state and remains depressed after that, the torque suddenly increases at the time of departure by the second speed engagement element after the first speed engagement element is released. There is a possibility of sudden departure. Therefore, the control device 10 can instruct the ECU 11 to control the torque at the time of starting by the second-speed engagement element so as to suppress the torque increase to a specified increase rate. Further, the released first-speed engagement element can be disabled until maintenance is performed. If the control device 10 confirms that there is no abnormality by performing a valve check or the like, temporary oil caused by dust is used. It can also be reused temporarily, judging that the road is clogged.

  Returning to the flowchart of FIG. 2, when the release is not completed in step S <b> 7, the control device 10 determines in step S <b> 10 whether a specified time has elapsed. If the specified time is too long, there is a possibility that the fastening element in the interlocked state generates heat. Therefore, an appropriate specified time is determined based on the type of friction engagement element and the vehicle speed. The control device 10 returns to step S7 while the specified time has not elapsed, and determines release completion. On the other hand, the control device 10 when the specified time has elapsed cancels the forced torque down control and allows the torque to increase in step S11.

  In step S12, the control device 10 that has canceled the forced torque-down control excludes the first-speed engagement element that could not be released from the shift control as unused, and engages the friction engagement element constituting the second speed to perform the shift control. Execute. In succession, in step S13, the control device 10 warns the driver of the stop by a warning light such as an instrument panel, a buzzer, a synthesized voice, or the like. That is, since the vehicle is traveling without releasing the interlock state of the first-speed engagement element, it is notified that the vehicle should stop immediately. And the control apparatus 10 judges whether a shift range can be put into P (parking) or N (neutral) range, and confirms a stop.

  When it is confirmed that the shift range has become the P or N range, the control device 10 executes an oil passage cleaning process in step S15. In the oil passage cleaning process, oil pressure is intermittently applied to the oil passages related to the interlocking engagement elements, and the oil passage clogging is eliminated. If the interlock state is eliminated by the oil passage cleaning process, the process returns to the start of FIG.

  When the interlock state is detected by the control device 10 executing the above torque reduction processing flow, the torque reduction of the engine 1 is executed according to the vehicle speed, and is forced by the action of the engine brake by the torque reduction. The vehicle can be decelerated and finally stopped. The lower the vehicle speed, the easier it is to release the fastening element because the release can be performed in a state where the load applied to the interlocking fastening element is low. In addition, in this respect, it is possible to suppress sudden acceleration that may be generated as a result of connecting another engaging element (shifted speed after shifting) when releasing the interlocked engaging element. The fastening element release control logic can be simplified, and the fastening element can be released more easily. Furthermore, by reducing the torque, the load on the device in which the interlocked fastening element is forcibly dragged is also reduced. Further, since the control device 10 executes the forced torque down control after judging the vehicle speed, the torque reduction is executed when the vehicle speed is less than the vehicle speed at which there is no problem even if the vehicle is decelerated to the extent of stopping. It is possible to control according to the situation.

  In the flowchart of FIG. 2 described above, the case of shifting up from the first speed (low gear) to the second speed (high gear) at the time of departure is described as an example, but the second speed to the first speed when decelerating toward the stop is explained. The torque-down process can also be executed when the vehicle is downshifted or when the accelerator is depressed during deceleration to kick-down from the second speed to the first speed. A time chart in this case is shown in FIG. 3B.

  In the time chart of FIG. 3B, the vehicle is decelerating to stop, the accelerator opening is in a closed state, and the torque of the engine 1 is maintained in a predetermined state. The sub-transmission 3 is going to shift down from the 2nd speed to the 1st speed as the vehicle is decelerated, but an interlock state is generated in the 2nd-speed engagement element. The control device 10 detects the interlock state of the second speed engagement element, and reduces the torque of the engine 1 if the vehicle speed is equal to or lower than the specified vehicle speed. When torque-down is executed, the torque starts to decrease at a specified decrease rate (arrow Tramp). When the torque is reduced, the vehicle speed is reduced by the action of the engine brake (arrow Sramp), and when the speed drops to a speed suitable for releasing the 2-speed engagement element or when the vehicle stops, the 2-speed engagement element is released. The Thus, when the second speed engagement element is released, torque reduction is released and the friction engagement element constituting the first speed is engaged. Thereafter, when the accelerator is stepped on to depart and the accelerator opening is opened, the torque increases and the first speed engagement element travels. The released two-speed engagement element can be disabled until maintenance is performed, and can be reused temporarily if the control device 10 confirms that there is no abnormality through a valve check or the like. .

  In the flowchart of FIG. 2, the forced torque down control in step S5 can also be executed by a subroutine shown in FIG. The flowchart shown in FIG. 4 is an example in which a different reduction rate corresponding to the accelerator opening is adopted for the specified reduction rate of the engine torque. That is, in the flowchart of FIG. 4, when the vehicle speed is equal to or lower than the specified vehicle speed, the control device 10 as the torque down control means compares the detected accelerator opening with the specified accelerator opening, and determines the engine according to the comparison result. Change the torque reduction rate.

In this case, the control device 10 that performs the function as the vehicle state detection unit also detects the accelerator opening degree of the vehicle state information acquired from the ECU 11. Then, the control device 10 that has executed the function as the torque-down control means and started the forced torque-down control first executes torque-down at the specified reduction rate as described in step S5 of FIG. Alternatively, torque reduction may be executed at a slow decrease rate set in step S22 described later. Subsequently, in step S20, the control device 10 compares the detected accelerator opening with the specified accelerator opening. The prescribed accelerator opening is a threshold value that can determine that the driver does not intend to accelerate, and may be a value indicating the closed state (opening = 0), but may not necessarily be a value indicating the fully closed state. That is, when it is once determined in step S20 that the detected accelerator opening is greater than the prescribed accelerator opening, after performing the steps described later, when returning to step S20 and performing comparison again, this recomparison is performed. If the accelerator opening detected at the time is equal to or less than the specified accelerator opening, it can be determined that the accelerator is loosened (that is, not accelerated).

  If the detected accelerator opening is equal to or less than the specified accelerator opening, the control device 10 executes a rapid torque reduction in step S21 and instructs the ECU 11 to reduce the torque of the engine 1 at a rapid decrease rate. This rapid torque down is intended to stop the vehicle as soon as possible to release the fastening element. For example, the ECU 11 is instructed to set the target torque value = 0 (torque down limit value) to cause the torque to drop sharply. Increase the engine brake action. In addition, by decreasing the decrease rate when the vehicle speed is reduced to a predetermined vehicle speed due to rapid torque reduction, it is possible to relieve the feeling of deceleration before stopping. After executing the rapid torque reduction in step S21, the control device 10 proceeds to step S6 in FIG.

A time chart when this rapid torque reduction is executed is shown in FIG. 5A.
An interlock state is detected at the time of departure as in FIG. 3A, and torque reduction is started by determining that the vehicle speed is equal to or less than a specified value. Then, when the driver turns off the accelerator, the accelerator opening shifts to the closed position (arrow Aramp). When the accelerator opening is determined to be less than the specified value, the rapid decrease rate is applied to rapidly reduce the torque. (Show arrow 1). Following the torque reduction, the vehicle speed also drops sharply (Sramp1). When the vehicle is decelerated to a predetermined vehicle speed, the rate of torque reduction is relaxed (arrow Tramp2), and the speed of the vehicle decreases gradually (arrow Sramp2), and finally the vehicle stops. When the vehicle speed drops to a speed suitable for releasing the first-speed engagement element or when the vehicle stops, an instruction to release the first-speed engagement element is given. When releasing the fastening element, the lower the vehicle speed, the lower the load of the fastening element, and thus the easier it is to release (the vehicle speed is the lowest when the vehicle is stopped). In addition, if the fastening element is released before the vehicle stops, the driver may be given a feeling that the engine brake is temporarily released at the time of release, but this feeling of incongruity can be avoided if the vehicle is stopped. . When the first speed engagement element is released, torque reduction is released and the friction engagement element constituting the second speed is engaged. When the accelerator is stepped on by releasing the interlock state and the accelerator opening is opened, the torque is increased and traveling is performed by the second speed engagement element.

  Returning to FIG. 4, when the specified accelerator opening is exceeded in step S20, the control device 10 executes slow torque reduction in step S22. The control device 10 instructs the ECU 11 to reduce the torque of the engine 1 at a slow decrease rate by the slow torque reduction. This slow torque down is a torque down assuming that the vehicle is located in a stop prohibited area such as an intersection or railroad crossing, and allows the vehicle to continue running until it exits the stop prohibited area. For this reason, for the slow decrease rate of the torque, for example, a value that is not stopped by the engine brake within 10 m from the current vehicle speed is calculated. In step S23, the control device 10 that has executed the slow torque reduction in step S22 determines whether or not the specified time has elapsed. As a result, if the specified time has passed, the control device 10 executes a rapid torque reduction in step S21, and reduces the vehicle speed as soon as possible to release the fastening element.

  The specified time used for this determination is set as a grace time for allowing the vehicle to escape from the stop prohibited area. In other words, the specified time needs to be long enough to escape from the stop-prohibited area with slow torque reduction, but if it is too long, it will lead to heat generation and wear of the fastening elements. And For example, the specified time can be determined such that the vehicle can travel 10 m at a vehicle speed of about 5 km / h.

  If it is within the specified time in step S23, the control device 10 determines in step S24 whether or not the accelerator opening increases. If the accelerator opening does not increase, the control device 10 starts again from step S20. On the other hand, if the accelerator opening increases, it means that the driver has stepped on the accelerator in order to keep the vehicle running for some reason. Therefore, the controller 10 suppresses the torque reduction in step S25, Returning to S20, it is determined again whether the accelerator opening is equal to or less than the specified accelerator opening.

FIG. 5B shows a time chart when this slow torque reduction is executed.
An interlock state is detected at the time of departure as in FIG. 3A, and torque reduction is started by determining that the vehicle speed is equal to or less than a specified value. If the accelerator is not loosened (arrow Aramp1) or is depressed in reverse, it is determined that the accelerator opening exceeds the specified value, and a slow decrease rate is applied to slowly reduce the torque (arrow Indication Tramp1). Following the torque reduction, the vehicle speed is also slowly reduced (arrow Sramp1). During this slow torque reduction, if the accelerator is depressed and the accelerator opening is increased (arrow Aramp2), the torque reduction is temporarily suppressed (arrow Tramp2), and the vehicle speed is also temporarily increased accordingly. Go up (arrow Sramp2). After that, again, when the accelerator opening is compared with the specified value, it is determined that the accelerator opening exceeds the specified value (arrow Aramp3), so the slow torque down is executed again (arrow Tramp3). As a result, the vehicle speed also slowly decreases (arrow Sramp3).

  Subsequently, if the specified time elapses during execution of the slow torque reduction, the rapid torque reduction is executed at this time, and the torque is rapidly reduced by applying the rapid decrease rate (arrow Tramp4). Following the torque reduction, the vehicle speed also drops sharply (Sramp4). Then, when the driver loosens the accelerator, the accelerator opening also shifts to close (arrow Aramp4). Finally, when the vehicle speed drops to a speed suitable for releasing the first-speed engagement element or when the vehicle stops, an instruction to release the first-speed engagement element is given. Thus, when the first speed engagement element is released, the torque reduction is released and the friction engagement element constituting the second speed is engaged. When the accelerator is stepped on by releasing the interlock state and the accelerator opening is opened, the torque is increased and traveling is performed by the second speed engagement element.

  As described above, according to the forced torque down control of FIG. 4, even when the vehicle is stopped to release the interlocking element in the interlocked state, the engagement element releasing is performed according to the driver's intention according to the surrounding situation. Therefore, it is selected whether to stop urgently or to travel after a certain distance. Therefore, when the vehicle is located at an intersection or railroad crossing, the interlock state can be canceled while allowing traveling according to the situation, such as giving a grace to escape from the area.

  FIG. 6 is another subroutine relating to the forced torque down control in step S5 in the flowchart of FIG. The flowchart shown in FIG. 6 is an example in which different reduction rates are adopted for the specified reduction rate of the engine torque based on navigation information obtained from the car navigation system 12. That is, in the flowchart of FIG. 6, when the vehicle speed is equal to or less than the specified vehicle speed, the control device 10 as the torque down control means determines the vehicle surrounding situation based on the detected navigation information, and determines the vehicle surrounding situation. The engine torque reduction rate is changed accordingly.

  In this case, the control device 10 that performs the function as the vehicle state detection means also detects the navigation information acquired from the car navigation system 12. Then, the control device 10 that has executed the function as the torque-down control means and started the forced torque-down control first executes torque-down at the specified reduction rate as described in step S5 of FIG. Alternatively, torque reduction may be executed with the above-mentioned slow decrease rate. Subsequently, in step S30, the control device 10 determines whether or not a short-distance stop is possible based on the detected navigation information as a determination of the situation around the vehicle. For example, it is determined whether or not the vehicle position is not a large street such as a road with four or more lanes, and whether or not the vehicle is away from a stop prohibited area (crossing, intersection, etc.). Specifically, for example, it is determined whether or not the own vehicle position is 30 m or more away from a railroad crossing or an intersection. That is, if the vehicle position is not a large street and is away from the stop prohibited area, it is better to stop the vehicle at a short distance before approaching the stop prohibited area. As a result, if the vehicle can be stopped for a short distance, the control device 10 performs the rapid torque reduction similar to the above in step S31 (see FIG. 5A), and proceeds to step S6 in FIG.

  When the short-distance stop is impossible in step S30, in step S32, the control device 10 determines whether or not the vehicle is in the vicinity of a stop-prohibited area this time as a determination of the surrounding state of the vehicle based on the navigation information. For example, it is determined whether or not the vehicle position is a large street and whether or not it is within 5 m of a railroad crossing and an intersection as a stop prohibited area. That is, if the vehicle position is large or close to the stop prohibited area, it is better to travel to some extent and escape from the position, so this is determined. As a result, if it is in the vicinity of the stop-prohibited area, the control device 10 executes the slow torque reduction similar to the above in step S33, and performs the same prescribed time passage determination in step S34. Then, if it is within the specified time, the control device 10 determines whether or not the accelerator opening increases in the same manner as described above in step S35. If the accelerator opening does not increase, the control device 10 starts again from step S30. On the other hand, when the accelerator opening increases, similarly to the above, the control device 10 suppresses the torque reduction in step S36 and returns to step S30 (see FIG. 5B).

  On the other hand, when it is not near the stop prohibition area in step S32, the control device 10 determines whether or not the stop prohibition area is in front of the vehicle in step S37. If it is not possible to stop for a short distance in step S30 and it is not in the vicinity of the stop prohibited area in step S32, in a specific example, it is not a large street but is located at least 5m away from the stop prohibited area and within 30m. It means that. Therefore, in this case, the rapid torque down and the slow torque down are selected depending on whether the vehicle is moving to the stop prohibited area or away from the stop prohibited area. That is, if the stop prohibited area is in front of the vehicle in step S37, the control device 10 executes the rapid torque reduction in step S31 and stops before approaching the stop prohibited area because the vehicle is moving to the stop prohibited area. Let On the other hand, if the stop prohibited area is not in front of the vehicle in step S37, the vehicle has moved away from the stop prohibited area. Therefore, slow torque down is executed in step S33, and the vehicle is stopped as far as possible from the stop prohibited area.

  FIG. 7 is still another subroutine related to the forced torque down control in step S5 in the flowchart of FIG. The flowchart shown in FIG. 7 is an example in which the specified reduction rate of the engine torque is changed in accordance with the change in the accelerator opening so that the vehicle is decelerated and stopped as soon as possible to perform the shift. That is, in the flowchart of FIG. 7, when the vehicle speed is equal to or lower than the specified vehicle speed, the control device 10 as the torque down control means decreases the engine torque at a specified decrease rate and increases the detected accelerator opening. If the accelerator opening is increasing, the engine torque decrease rate is increased.

  In this case, the control device 10 that performs the function as the vehicle state detection unit also detects the accelerator opening degree of the vehicle state information acquired from the ECU 11. And the control apparatus 10 which performed the function as a torque down control means and started forced torque down control performs initial torque reduction in step S40. At the time of the initial torque reduction, the control device 10 instructs the ECU 11 to reduce the torque by which the torque of the engine 1 is dropped stepwise by several% to several tens% at a stroke, not a temporary decrease. Thereby, for example, the vehicle speed is reduced to 5 km / h. Alternatively, the torque reduction amount instruction value instructed at this time may be determined each time according to the traffic situation around the vehicle determined from the navigation information.

  In step S41, the control device 10 that has executed deceleration at the initial torque reduction executes torque reduction at the specified reduction rate as described in step S5 of FIG. That is, when the vehicle speed is equal to or lower than the specified vehicle speed in step S3 of FIG. 2, the control device 10 reduces the torque of the engine 1 in two stages, that is, initial torque reduction and torque reduction with a gentler decrease rate. Run. And the control apparatus 10 judges the increase in the detected accelerator opening in step S42, performing torque reduction by a regular reduction rate.

  If the detected accelerator opening has not increased, the control device 10 determines in step S43 whether the torque reduction of the engine 1 has reached a limit or whether the vehicle has stopped. On the other hand, if the accelerator opening has increased in step S42, the control device 10 increases the torque reduction rate in step S43, and in step S43, whether or not the torque has been reduced or stopped. Judging. As a result of the torque reduction, if the torque reduction amount instruction value reaches the upper limit or the vehicle speed included in the vehicle state information becomes zero in step S43, the control device 10 proceeds to step S6 in FIG.

FIG. 8 shows a time chart when torque reduction is executed in accordance with the change in the accelerator opening.
An interlock state is detected at the time of departure as in FIG. 3A, and torque reduction is started by determining that the vehicle speed is equal to or less than a specified value. When the interlock state is detected, an initial torque down is first instructed (arrow Iramp1), and the torque is stepped down (arrow Tramp1). Following this, the vehicle speed drops sharply (arrow Sramp1). Subsequently, a more gradual decrease rate is instructed (arrow Iramp2), and the torque decreases according to the decrease rate (arrow Tramp2), and accordingly, the vehicle speed gradually decreases (arrow Sramp2). During this time, if the driver depresses the accelerator and the accelerator opening increases (arrow Aramp1), an instruction to increase the torque reduction rate is given (arrow Iramp3), and the torque decrease rate becomes abrupt (arrow Tramp3). The vehicle speed also drops sharply (arrow Sramp3). When the torque down limit is instructed (arrow Iramp4, Tramp4) or when the vehicle stops before (arrow Sramp4), the release of the first speed engagement element is instructed. When the first speed engagement element is released, torque reduction is released and the friction engagement element constituting the second speed is engaged.

  When the torque down is released (step S9), when the torque is increased in accordance with the switching from the first speed to the second speed, the control device 10 determines the rate of increase in torque according to the accelerator opening (arrow Iramp5, (Tramp5), control to prevent sudden start. Alternatively, the control device 10 may set a target time for torque increase, and during this time, torque may be increased at a specified rate of increase. Further, the control device 10 can notify the driver that the vehicle is accelerated by switching to the second speed with a warning light or a buzzer.

  As a result of the execution of the forced torque reduction control shown in FIG. 7, when the driver shows an intention to accelerate, the vehicle can be decelerated and stopped quickly to release the interlocked engagement element and shift the speed. As a result, it is possible to respond quickly to the driver's intention to accelerate, cope with the interlock state, respond to acceleration, and also protect the transmission. However, in this case, deceleration that is temporarily different from the driver's intention occurs temporarily, giving a sense of incongruity in pulling torque.

  FIG. 9 is still another subroutine relating to the forced torque down control in step S5 in the flowchart of FIG. The flowchart shown in FIG. 9 is also an example in which the specified reduction rate of the engine torque is changed in accordance with the change in the accelerator opening so that the vehicle is decelerated and stopped as soon as possible to perform the shift, and the driver is decelerated during deceleration. Is a flow when the accelerator is off.

  The flow from step S50 to step S51 is the same as that in steps S40 to S41 in FIG. 7, and the control device 10 performs the torque of the engine 1 in two stages, that is, initial torque down and torque reduction at a slower rate than this. Run down. Then, the control device 10 determines from the accelerator opening whether or not the accelerator OFF occurs in step S52 while executing the torque reduction at the specified reduction rate.

  If the accelerator OFF does not occur, the control device 10 determines in step S53 whether the torque reduction of the engine 1 has reached a limit or whether the vehicle has stopped. When the torque reduction amount instruction value reaches the upper limit or the vehicle speed becomes 0 in step S53, the control device 10 proceeds to step S6 in FIG. On the other hand, if the accelerator OFF occurs in step S52, the control device 10 sets the torque reduction amount instruction value to the limit (maximum) at a stroke, not a temporary decrease, in step S54, and the torque of the engine 1 at a stroke. Drop it. And the control apparatus 10 progresses to step S6 of FIG.

FIG. 10 shows a time chart in the case where torque reduction corresponding to the accelerator OFF is executed.
An interlock state is detected at the time of departure as in FIG. 3A, and torque reduction is started by determining that the vehicle speed is equal to or less than a specified value. When the interlock state is detected, an initial torque down is first instructed (arrow Iramp1), and the torque is stepped down (arrow Tramp1). Following this, the vehicle speed drops sharply (arrow Sramp1). Subsequently, a more gradual decrease rate is instructed (arrow Iramp2), and the torque decreases according to the decrease rate (arrow Tramp2), and accordingly, the vehicle speed gradually decreases (arrow Sramp2). In the middle of this, when the driver turns off the accelerator (arrow Aramp1), the limit value of the torque decrease is indicated (arrow Iramp3), the torque is stepped down to the limit value (arrow Tramp3), and the vehicle speed also drops sharply. (Arrow Sramp3). When the vehicle is decelerated to a vehicle speed suitable for releasing the first-speed engagement element or stopped, the release of the first-speed engagement element is instructed. When the first speed engagement element is released, torque reduction is released and the friction engagement element constituting the second speed is engaged.

  In this case, the torque down limit value instruction is maintained until the switching from the first speed to the second speed is completed, and during this time, even if the driver depresses the accelerator, the vehicle does not depart. In addition, the torque reduction is released with the switching from the first speed to the second speed, and thereafter, the vehicle starts and accelerates according to the driver's accelerator work. At this time, the control device 10 can notify the driver that the vehicle is accelerated by switching to the second speed with a warning light, a buzzer, or the like.

  7 and 9 can be executed in parallel.

  The technical ideas other than the claims that can be grasped from the above embodiment will be described below together with the effects.

(A) In the control device according to claim 1,
The vehicle state detection means includes an accelerator opening in a vehicle state to be detected,
The torque down control means compares the accelerator opening detected by the vehicle state detection means with the specified accelerator opening when the vehicle speed is equal to or lower than the specified vehicle speed, and determines the engine torque reduction rate according to the comparison result. A control device that changes.
According to this control device, even when stopping to release the interlocking element in the interlock state, depending on the driver's intention according to the surrounding situation, to stop urgently to release the fastening element, or It is selected whether to stop after driving a certain distance.

(B) In the control device according to any one of claims 1 to 3 or (a),
A control device that notifies the driver of the occurrence of the interlock state when the interlock detection means detects the interlock state.
According to this control device, the driver can grasp that the interlock state has occurred, and the uncomfortable feeling of “torque pulling” accompanying the subsequent torque reduction can be reduced.

(C) In the control device according to any one of claims 1 to 3 or (a),
A control device that performs release of the interlocked engagement element after the torque-down control means starts to reduce engine torque.
According to this control device, the fastening element can be released in a state where the vehicle speed is sufficiently lowered or stopped due to the torque reduction, so that it is easy to control the release.

(D) In the control device according to claim (c),
A control device that suppresses to a specified rate of increase when engine torque increases after releasing the interlocking engagement element.
According to this control device, sudden start can be prevented at the first start after the interlock state is released.

(E) In the control device according to claim (c),
When the interlocked engagement element is released, and the engine torque is not released even after a specified time has elapsed, release of the engine torque by the torque-down control means is released, and the interlocked engagement element is excluded. A control device that executes shift control.
According to this control device, when the interlocked engagement element cannot be released, the vehicle is allowed to travel as an emergency measure, and travel to a parking area such as a parking zone is allowed.

(F) In the control device according to claim (e),
A control device that executes a shift control while excluding the interlocking element in the interlock state and warns the driver to stop.
According to this control device, the driver is warned that the vehicle is traveling without releasing the interlocking state of the fastening element, and the vehicle is promptly stopped.

(G) In the control device according to claim (e),
A control device that executes an oil passage cleaning process when the shift range becomes the P or N range after performing the shift control by removing the interlocking engagement element.
According to this control device, since the oil path cleaning process cannot be performed during traveling, the oil path cleaning process is executed after the shift range enters the P or N range and the vehicle is surely stopped, and the cause of the interlock is eliminated. Can be planned.

(H) In the control device according to claim (a),
The torque-down control means compares the accelerator opening detected by the vehicle state detection means with the specified accelerator opening, and as a result, if it is equal to or less than the specified accelerator opening, a rapid decrease rate is obtained and exceeds the specified accelerator opening. Is a control device with a slow reduction rate.
According to this control device, the distance to the stop can be changed according to the driver's intention according to the situation around the host vehicle.

(L) In the control device according to claim (h),
The torque reduction control means is a control device that, when decelerated to a predetermined vehicle speed by reducing the engine torque that is the rapid decrease rate, loosens the decrease rate.
According to this control device, the feeling of deceleration is eased before the vehicle stops.

(Nu) In the control device according to claim (h),
When the engine torque is reduced at the slow reduction rate, the torque down control means reduces the engine torque at a rapid reduction rate when a specified time has elapsed.
According to this control device, after traveling the required distance with a slow decrease in torque during a specified time, a rapid decrease in torque is executed and the vehicle speed is quickly reduced to release the fastening element.

(L) In the control device according to claim (h),
The control device, wherein the torque-down control means suppresses the engine torque from being reduced when the accelerator opening is increased while the engine torque is being reduced at the slow decrease rate.
According to this control device, it is possible to cope with a case where the driver wants to continue traveling for some reason.

(W) In the control device according to claim 3,
The torque down control means determines whether or not a short-distance stop is possible as the situation surrounding the host vehicle, and if the short-distance stop is possible, sets the rapid decrease rate.
According to this control device, the vehicle can be stopped at a short distance before approaching the stop prohibited area.

(W) In the control device according to claim (W),
If the short stop is impossible, the torque down control means determines whether or not the vehicle is in the vicinity of the stop prohibited area as the surrounding situation of the host vehicle. .
According to this control device, if the vehicle is close to the stop prohibited area, the vehicle can be stopped after having traveled to some extent and escaped from the position.

(F) In the control device according to claim (W),
The torque-down control means determines whether or not the stop prohibited area is in front of the vehicle unless it is in the vicinity of the stop prohibited area. If the stop prohibited area is in front of the vehicle, the torque reduction control means determines a rapid decrease rate. A control device with a slow rate of decrease if it is not in front.
According to this control device, when the stop prohibited area is in front of the vehicle, the vehicle can be stopped before approaching, and when the stop prohibited area is not in front of the vehicle, the stop can be stopped after leaving.

(Yo) In the control device according to claim 2,
The torque-down control means is a control device that, when the vehicle speed is equal to or less than the specified vehicle speed, causes the engine torque to be reduced in two stages: an initial torque-down and a torque-down with a gentler decrease rate.
According to this control device, the vehicle can be greatly decelerated by the initial torque reduction, and can be stopped as short as possible.

(T) In the control device according to claim 1,
The vehicle state detection means includes an accelerator opening in a vehicle state to be detected,
The torque down control means reduces the engine torque at a specified reduction rate when the vehicle speed is equal to or less than the specified vehicle speed, and determines whether or not the accelerator is turned off from the accelerator opening detected by the vehicle state detecting means. Judgment is made, and when the accelerator is OFF, the amount of decrease in engine torque is set to a limit value.
According to this control device, when the driver turns off the accelerator for the purpose of stopping, the vehicle can be stopped as short as possible.

1 Engine 2 Torque converter 3 Automatic transmission 3a, 3c Pulley 3b Belt 3d Sub-transmission

Claims (1)

A control device for an automatic transmission for a vehicle that selectively engages a plurality of friction engagement elements by hydraulic pressure and switches a gear position,
An interlock detection means for detecting an interlock state of the fastening elements fastened among the friction engagement elements;
Vehicle state detection means for detecting a vehicle state including at least the vehicle speed and the accelerator opening ;
A torque down control means for determining at least a vehicle speed detected by the vehicle state detection means when the interlock detection means detects an interlock state, and reducing an engine torque when the vehicle speed is equal to or lower than a specified vehicle speed;
It is configured to include a,
The torque-down control means compares the accelerator opening detected by the vehicle state detection means with the specified accelerator opening, and as a result, if it is equal to or less than the specified accelerator opening, a rapid decrease rate is obtained and exceeds the specified accelerator opening. Is a control device with a slow reduction rate .

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