JP2020118274A - Control device of automatic transmission - Google Patents

Abstract

To perform a downshift from a neutral state accompanied by an acceleration requirement without causing a shock and an overshoot of a rotation number.SOLUTION: A control device of an automatic transmission detects an increase requirement of a drive force when traveling while setting the automatic transmission to a neutral state (step S2), acquires an initial gear change stage which should be set by the automatic transmission by the detection of the increase requirement of the drive force (step S3), starts the engagement of an engagement mechanism which is engaged in order to set the initial gear change stage (step S4), determines that an input rotation number of the automatic transmission reaches a rotation number which is acquired on the basis of a gear change ratio of the initial gear change stage in the middle of an increase of a transmission torque capacity of the engagement mechanism, and before a finish of the setting of the initial gear stage (step S7), and starts the control of a downshift to a gear change stage corresponding to the increase requirement of the drive force when the determination is established (step S8).SELECTED DRAWING: Figure 5

Description

The present invention relates to a device for controlling a shift of an automatic transmission mounted on a vehicle, and more particularly to a device for controlling a stepped automatic transmission capable of setting a plurality of shift stages.

An automatic transmission for a vehicle is a device that is arranged between a drive force source and a drive wheel to transmit torque between the two and to amplify and reduce the transmitted torque. Therefore, during traveling, a predetermined gear ratio is set according to the vehicle speed, the required driving force, and the like. However, recently, due to demands such as improvement of fuel consumption and reduction of greenhouse effect gas, even if the driving force (accelerating force) and the braking force are not particularly required even while traveling, the automatic transmission is neutralized. It is becoming more common to control the engine to a state, to stop the engine by disconnecting it from the drive wheels, or to reduce the output.

For example, in Patent Document 1, a motor is provided as a driving force source in addition to an engine, and two stages are provided in front of a power split mechanism (input side) that splits torque output from the engine into a generator side and an output side. A control device for a hybrid vehicle provided with a shift mechanism capable of shifting is described. This control device is configured to release the clutch and the brake in the transmission mechanism to bring the transmission into a neutral state when the engine is stopped and the vehicle travels by the motor. According to the device described in Patent Document 1, when the engine is started according to the change of the drive mode, a predetermined shift state (shift stage) is set by engaging a clutch or a brake so as to rotate the engine. It Therefore, the engine can be started quickly when switching to the hybrid (HV) mode.

Further, in Patent Document 2, in a control device for a hybrid vehicle, heat generation of a clutch is suppressed and acceleration responsiveness is improved when the engine is started with a downshift due to an acceleration request. A device capable of doing so is described. According to the device described in Patent Document 2, when the engine is cranked by engaging the so-called start clutch provided at the front stage (input side) of the transmission mechanism, the start clutch does not slip. Until then, the engagement mechanism that sets the shift speed before shifting is maintained at a low engagement force that does not cause slip, and the engagement mechanism that engages at the shift speed after shifting immediately increases due to the increase in the engaging force. Waiting for torque transmission. Therefore, since the slip of the starting clutch occurs in the state where the gear ratio is small, that is, the input rotational speed is small, the heat generation of the starting clutch is suppressed.

Further, Patent Document 3 describes a control device for a hybrid vehicle in which an engine is connected to an input shaft of a power split mechanism via a starting clutch and a motor is connected to the input shaft. According to the device described in Patent Document 3, the starting clutch is engaged when shifting from the EV traveling mode in which the motor is used as the driving force source to the hybrid (HV) traveling mode in which the engine is used as the driving force source. And then ignite the engine. Therefore, it is said that it is possible to quickly start the engine and shift to the HV traveling mode.

JP, 2018-12410, A JP, 2014-151907, A International Publication No. 2012/059996

As described above, the automatic transmission is set to the neutral state while the vehicle is traveling for the purpose of improving fuel efficiency and reducing exhaust gas. In a vehicle that performs this type of control, the automatic transmission is set to a predetermined shift speed, for example, when an acceleration request is generated. In this case, if the engagement mechanism that engages or disengages to set the shift speed is not properly controlled, the input rotation speed (engine rotation speed or driving power source rotation speed) may overshoot or shock May occur. Further, prior to setting the shift speed corresponding to the acceleration request, a so-called initial shift speed suitable for the running state at the time when the acceleration request is generated is set, and then the shift speed corresponding to the acceleration request is changed. It is possible. By performing such control, it is possible to set the initial gear stage without causing a shock, etc., because the initial gear stage is the gear stage suitable for the running state at that time, and the subsequent acceleration Since the shift to the shift speed according to the request is a normal shift, a smooth shift as usual can be performed. However, since the gear change executed by the acceleration request is the gear change for setting the initial gear from the neutral state and the gear change from the initial gear to the gear corresponding to the acceleration request, the acceleration request is generated. It takes a longer time to generate a driving force corresponding to the above, and the acceleration response is impaired.

The device described in Patent Document 1 described above sets the speed change mechanism to a neutral state during traveling, and sets the speed change mechanism to a predetermined shift speed when a predetermined condition such as an acceleration request is satisfied. However, the speed change mechanism is a speed change mechanism arranged between the engine and the power split mechanism, and the reason why the shift speed is set is to transmit the traveling inertia force to the engine and rotate the engine together. Therefore, the shift control to the shift stage for starting the engine and the shift control from the shift stage to another shift stage do not overlap with each other. Therefore, the control device described in Patent Document 1 has the above-described initial stage. It cannot be applied to the control for setting the shift speed and shifting to the shift speed in response to the subsequent acceleration request.

On the other hand, in the device described in Patent Document 2, the automatic transmission is set to a predetermined shift speed when the engine is started during traveling, and is a device for performing control when downshifting from the shift speed. Is. That is, the gear shift control by the device described in Patent Document 2 is a control for downshifting from the already established gear stage. Therefore, the device described in Patent Document 2 is the same as that of Patent Document 1 described above. Like the described device, it cannot be applied to the control for setting the initial gear shift stage described above and subsequently performing a downshift.

The control described in Patent Document 3 is a control in which the order of the starting clutch and the ignition of the engine is defined in a predetermined order. Therefore, the device of Patent Document 3 can be applied to the setting of the initial shift stage and the control for performing the downshift subsequently to the initial shift stage even if the shift mechanism is brought into the substantially neutral state by releasing the starting clutch. Can not.

The present invention has been made in view of the above-mentioned technical problem, and based on an acceleration request, a so-called initial shift stage is set from a neutral state, and then a shock control for setting a shift stage according to the acceleration demand is performed. An object of the present invention is to provide an automatic transmission control device that can be executed without causing a delay.

In order to achieve the above object, the present invention has a plurality of engagement mechanisms capable of continuously changing the transmission torque capacity, and engages the plurality of engagement mechanisms according to the running state of the vehicle. Control of an automatic transmission capable of setting a plurality of shift speeds by releasing and releasing any one of the engagement mechanisms while the vehicle is traveling and setting a neutral state in which torque is not transmitted. In the device, a controller for controlling the shift of the automatic transmission is provided, and the controller detects a request for increasing the driving force when traveling while setting the automatic transmission in a neutral state, When the increase request is detected, the initial gear stage to be set in the automatic transmission is determined, and the engagement of the engaging mechanism that is engaged to set the initial gear stage is started. While the transmission torque capacity of the automatic transmission is increasing and before the setting of the initial shift stage is completed, the input rotational speed of the automatic transmission has reached the rotational speed determined based on the gear ratio of the initial shift stage. Is determined, and when the determination is satisfied, the control of downshifting to the shift stage in response to the request for increasing the driving force is started.

In the present invention, the initial shift speed may be either a predetermined shift speed or a shift speed determined based on the vehicle speed of the vehicle at the time when the request for increasing the driving force is detected. ..

In the present invention, the controller determines in advance that the transmission torque capacity of the engagement mechanism determines that the input speed of the automatic transmission has reached the speed determined based on the speed ratio of the initial speed stage. That the predetermined torque capacity has been reached, that a predetermined time has elapsed from the time when the engagement of the engagement mechanism is started, the input speed of the automatic transmission, and the gear ratio of the initial gear stage, Either the deviation from the rotation speed obtained from the vehicle speed has reached a predetermined rotation speed, or the change rate of the input rotation speed of the automatic transmission has become below a predetermined reference change rate. It may be configured to be performed based on.

In this invention, the engagement mechanism includes a plurality of engagement-side engagement mechanisms whose engagement order is predetermined, and the transmission torque capacity of the engagement mechanism has reached a predetermined torque capacity. Is that the order of engagement is that the transmission torque capacity of the last engagement side engagement mechanism has reached a predetermined torque capacity, which is predetermined from the time when the engagement of the engagement mechanism is started. The elapse of time may be that a predetermined time has elapsed from the time when the engagement of the last engagement side engagement mechanism was started in the engagement order.

In the present invention, the automatic transmission further includes a first engagement mechanism that is disengaged at the initial shift stage and engaged at the time of the downshift so that the automatic transmission is engaged at the initial shift stage. The controlled engagement mechanism includes a second engagement mechanism that is released during the downshift, and the controller reduces the transmission torque capacity of the second engagement mechanism to start the downshift. Good.

In the present invention, the automatic transmission further includes a first engagement mechanism that is disengaged at the initial shift stage and engaged at the time of the downshift so that the automatic transmission is engaged at the initial shift stage. A second engagement in which the controlled engagement mechanism is released during the downshift, and the torque applied by the transmission torque capacity of the first engagement mechanism increases at the initial shift stage. A mechanism, and the controller sets the transmission torque capacity of the second engagement mechanism to be equal to or less than the shared torque in the initial shift stage, and increases the transmission torque capacity of the first engagement mechanism by increasing the transmission torque capacity of the first engagement mechanism. The one-engagement mechanism may be caused to slip to start the downshift.

In the present invention, the controller may be configured to release all of the plurality of engagement mechanisms to set the neutral state.

According to the present invention, when the automatic transmission is set to the neutral state during traveling and the predetermined shift speed is set in response to the increase request of the driving force, first, the control for setting the initial shift speed is started. The initial shift stage is a predetermined shift stage or a shift stage according to the traveling state at that time. Therefore, the shift control of the automatic transmission is started without waiting for the shift stage corresponding to the request for increasing the driving force to be determined or confirmed, so that the shift responsiveness is improved. Then, the downshift from the initial shift stage to the shift stage in response to the request for increasing the driving force is started. The downshift is in the process of increasing the transmission torque capacity of the engagement mechanism engaged to set the initial gear, and the input speed of the automatic transmission is equal to the gear ratio of the initial gear. It starts at the time when the number of rotations is obtained based on the above. The time point can be determined based on the input rotation speed, the elapsed time from the start of the engagement control of the engagement mechanism, and the like. Therefore, the downshift is started during the setting of the initial shift stage or before the setting of the initial shift stage is completed, so that the shift stage corresponding to the request for increasing the driving force can be set early and the acceleration response Is improved. In addition, the downshift starts when the input speed of the automatic transmission is controlled by performing control to set the initial speed, so the input speed is the synchronous speed at the speed after the downshift. It is possible to avoid or suppress a so-called upward blowing that increases beyond, and accordingly, a shock can be prevented or suppressed.

It is a block diagram which shows typically an example of the hybrid vehicle which can be made into object by this invention. It is a skeleton diagram showing an example of a gear train of the automatic transmission. It is a hydraulic circuit diagram showing a part of hydraulic circuit which controls the transmission torque capacity (engagement pressure) of the engagement mechanism. 6 is a table collectively showing engagement and disengagement states of an engagement mechanism for setting each shift speed. 6 is a flowchart for explaining an example of control executed in the embodiment of the present invention. Times showing changes in the accelerator opening, the gear position, the engine speed corresponding to the input speed of the automatic transmission, the longitudinal acceleration, and the engagement and disengagement states of the engagement mechanism when the control shown in FIG. 5 is performed. It is a chart. As a conventional example, regarding the control example in which the initial shift stage and the downshift are sequentially executed, the accelerator opening, the shift stage, the engine speed corresponding to the input speed of the automatic transmission, the longitudinal acceleration, and the engagement mechanism engagement. It is a time chart which shows each change of a release state. As a conventional example, regarding a control example in which a downshift is executed without performing control for setting an initial shift stage, an accelerator opening degree, a shift stage, an engine rotational speed equivalent to an input rotational speed of an automatic transmission, a longitudinal acceleration, 7 is a time chart showing changes in the engaged and released states of the coupling mechanism.

The automatic transmission targeted by the present invention may be a conventionally known stepped automatic transmission, and the number of shift stages that can be set is not particularly limited. Further, the driving force source to which the automatic transmission is connected is generally an internal combustion engine such as a gasoline engine, but is not limited to this, and a drive combining an internal combustion engine and a motor (motor/generator) having a power generation function. It may be a power source. That is, the automatic transmission of the present invention may be mounted on a hybrid vehicle. FIG. 1 schematically shows an example of a hybrid vehicle 2 equipped with an automatic transmission 1.

The hybrid vehicle 2 shown in FIG. 1 includes an engine 3 and two motors 4 and 5. More specifically, the hybrid vehicle 2 shown here is an example of a four-wheel drive vehicle based on a front engine/rear wheel drive vehicle (FR vehicle), and an engine (E/G) 3 is provided on the front side of the vehicle body. Is arranged toward the rear of the vehicle body, and a damper 7 is connected to an output shaft 6 of the engine 3 and a first motor (MG1) 4 is connected to the output shaft 6. The output shaft 6 is connected to the input shaft 8 of the automatic transmission (AT) 1. A rear differential gear 10 is connected to the output side of the automatic transmission 1 via a rear propeller shaft 9, and a drive torque is transmitted from the rear differential gear 10 to left and right rear wheels (driving wheels) 11. ..

An example of the automatic transmission 1 is shown in a skeleton diagram in FIG. The automatic transmission 1 shown here is configured so that 10 forward speeds can be set. The gear transmission unit 12 to which torque is input from the engine 3 and the first motor 4 via the input shaft 8 includes a Ravigneaux type first planetary gear mechanism 13, a single pinion type second planetary gear mechanism 14, and a single pinion. The third planetary gear mechanism 15 of the mold is provided as a main gear mechanism. The first planetary gear mechanism 13 has two sun gears S131 and S132, a ring gear R13, a first pinion gear P131 meshed with the sun gear S131 and ring gear R13, and a second sun gear S132 meshed with the first pinion gear P131. The carrier C13 that holds the two-pinion gear P132 is provided as a rotating element that performs a differential action with each other. A first brake B1 for selectively fixing the first sun gear S131 is provided.

The second planetary gear mechanism 14 and the third planetary gear mechanism 15 are arranged on the same axis as the first planetary gear mechanism 13 described above. The second planetary gear mechanism 14 includes a sun gear S14, a ring gear R14, and these. The sun gear S14 and the carrier C14 that holds the pinion gear P14 that meshes with the ring gear R14 are provided as rotating elements that perform a differential action with each other. Similarly, the third planetary gear mechanism 15 includes a sun gear S15, a ring gear R15, and a carrier C15 holding a pinion gear P15 meshing with the sun gear S15 and the ring gear R15, and a rotating element that performs a differential action with respect to each other. Is equipped with.

The sun gear S14 of the second planetary gear mechanism 14 and the sun gear S15 of the third planetary gear mechanism 15 are integrated with each other, and these sun gears S14, S15 and the ring gear R13 of the above-described first planetary gear mechanism 13 are selective. Is provided with a first clutch K1. A second clutch K2 is provided which selectively connects the sun gears S14, S15 and the second sun gear S132 of the first planetary gear mechanism 13 which are integrated with each other. Further, a third clutch K3 is provided which selectively connects the ring gear R14 of the second planetary gear mechanism 14 and the ring gear R13 of the first planetary gear mechanism 13. A second brake B2 for selectively stopping the rotation of the ring gear R14 of the second planetary gear mechanism 14 is provided.

The carrier C15 in the third planetary gear mechanism 15 serves as an input element of the gear speed change unit 12. Further, the carrier C14 of the second planetary gear mechanism 14 is an output element and is connected to the rear propeller shaft 9 via the output shaft of the gear transmission 12 (automatic transmission 1). A fourth clutch K4 is provided which selectively connects the carrier C14 of the second planetary gear mechanism 14 and the ring gear R15 of the third planetary gear mechanism 15 which are the output elements. When the fourth clutch K4 is engaged, the second planetary gear mechanism 14 and the third planetary gear mechanism 15 are integrally formed without causing a differential action by connecting two rotating elements to each other. And rotate.

Each of the clutches K1 to K4 and the brakes B1 and B2 is, for example, a friction type engagement mechanism that is engaged and released by hydraulic pressure, and its transmission torque capacity (transmittable torque) can be continuously changed. It is configured to be able to. An example thereof is shown in FIG. Each of the clutches K1 to K4 and the brakes B1 and B2 is connected to the line pressure oil passage PL via linear solenoid valves SLK1 to SLB2 provided corresponding to each of them. The linear solenoid valves SLK1 to SLB2 are pressure regulating valves configured to output a hydraulic pressure according to a current value or a duty ratio, and therefore, the respective clutches K1 to K4 and the brakes B1 and B2 are engaged and released and released. The transmission torque capacity can be electrically controlled by the linear solenoid valves SLK1 to SLB2 provided correspondingly. The clutches K1 to K4 and the brakes B1 and B2 correspond to the engagement mechanism in the embodiment of the present invention.

In the above-described automatic transmission 1 shown in FIG. 2, 10 forward gears (1st to 10th) and reverse gear (Rev) can be set. The engagement mechanism for engaging and releasing at these gears is shown collectively in the engagement operation table of FIG. In FIG. 4, the mark “◯” indicates the engaged state, and the blank indicates the released state. Control for engaging and disengaging these engagement mechanisms can be performed by a conventionally known hydraulic control device (not shown), and the hydraulic control device can be electrically controlled. The control is similar to the conventionally known gear shift control, and a gear shift map that defines the area of each gear is prepared in advance according to drive data (running state) such as accelerator opening and vehicle speed, and the accelerator opening is performed. The shift is executed when the degree and the vehicle speed change across a line (shift line) defining each region. Therefore, the target gear stage is determined by the required driving force such as the accelerator opening degree and the vehicle speed or the rotation speed of the rotating member corresponding thereto, and each engagement mechanism is engaged and released so as to set the target gear stage. .. As the shift control, not only control for changing the gears one by one, but also so-called jump shift to gears separated by two or more gears, or via an intermediate gear (intermediate gear) during jump shift It is possible to perform control such as so-called multiple speed change for setting the target gear stage.

On the other hand, the second motor 5 is connected to the front reduction gear 16. Further, an output member of the front reduction gear 16 is connected to a front differential gear 18 via a front propeller shaft 17, and the front differential gear 18 is configured to transmit a drive torque to the left and right front wheels (driving wheels) 19. ..

The engine 3 is an internal combustion engine such as a gasoline engine or a diesel engine, and the throttle opening and the fuel injection amount are controlled according to the required driving force such as the depression amount (accelerator opening) of an accelerator pedal (not shown). It is configured to output a torque according to the required driving force. The first motor 4 is a motor (motor/generator: MG) having a power generation function such as a permanent magnet type synchronous motor, and mainly functions as a power generator in the example shown in FIG. Moreover, since the first motor 4 is connected to the output shaft 6 of the engine 3, the engine 3 can be cranked (motored) by the first motor 4 when the engine 3 is started.

The front reduction gear 16 is a mechanism for amplifying the torque of the second motor (MG2) 5 and transmitting it to the front propeller shaft 17. In the example shown in FIG. 1, the front reduction gear 16 is composed of a counter gear pair and a planetary gear mechanism. Has been done. The counter gear pair has a drive gear 20 connected to the second motor 5 and a driven gear 21 having a diameter larger than that of the drive gear 20. The planetary gear mechanism holds a sun gear 22 connected to the driven gear 21, a ring gear 23, which is an internal gear arranged concentrically with the sun gear 22, a pinion gear meshing with the sun gear 22 and the ring gear 23, and also has a front propeller shaft. And a carrier 24 to which 17 is connected. Further, a brake 25 that selectively stops the rotation of the ring gear 23 is provided. The brake 25 may be a friction type or a meshing type engagement mechanism. Therefore, in the front reduction gear 16, the planetary gear mechanism does not idle to transmit torque by releasing the brake 25, and the carrier 25 rotates at a lower speed than the sun gear 22 by engaging the brake 25. Is configured to act. Since the torque of the second motor 5 is amplified by the counter gear pair and the planetary gear mechanism and transmitted to the front propeller shaft 17, the second motor 5 can be made a high-rotation, low-torque type and can be downsized. it can.

It should be noted that the second motor 5 can be configured by a motor (motor/generator: MG) having a power generation function such as a permanent magnet type synchronous motor, like the first motor 4 described above. Therefore, the second motor 5 functions as a motor to output a driving force for traveling to the front wheels 19 when a large uphill force or running performance on a bad road is required, and is transmitted from the front wheels 19 during deceleration. It is rotated by the generated torque to generate electricity.

Each of the motors 4 and 5 described above is connected to a motor controller 28 including a power storage device 26 and an inverter 27. Then, each of the motors 4, 5 and the motor controller 28 charges the power storage device 26 with the electric power generated by each of the motors 4, 5 and supplies the power of the power storage device 26 to each of the motors 4, 5 to supply the power to the motors 4 and 5. , 5 output torque from the first motor 4 and further supply electric power generated by the first motor 4 to the second motor 5 to output torque for traveling from the second motor 5.

The engine 3, the motors 4, 5, the automatic transmission 1, and the brake 25 are configured to be electrically controlled, and an electronic control unit (ECU) 29 is provided to control them. The ECU 29 is mainly composed of a microcomputer, for example, and is configured to perform an arithmetic operation using input data and prestored data and output the arithmetic operation result as a control command signal. Examples of the input data include the accelerator opening, which is the drive request amount, the vehicle speed, the engine speed, the input speed and the output speed of the automatic transmission, the remaining charge of the power storage device 26, and the like. The stored data is a speed change map, a mode map in which a traveling mode using the engine 3 as a driving force source, a traveling mode traveling with the second motor 5, and the like are determined according to the accelerator opening and the vehicle speed.

In the hybrid vehicle 2 described above, since the front wheels 19 can be driven by the second motor 5, it is possible to drive by driving only the second motor 5. In that case, in order to avoid the power loss caused by rotating the engine 3 and the first motor 4, the automatic transmission 1 is set to the neutral state and the engine 3 and the first motor 4 are separated from the rear wheel 11. In the embodiment described here, the neutral state is set by releasing all the engagement mechanisms K1 to K4, B1, B2 in the automatic transmission 1. This is to reduce the number of rotating members (rotating elements) of the automatic transmission 1 that rotate together with traveling as much as possible. In that case, the engine 3 may be stopped.

Such a traveling mode is a mode that can be referred to as a one-motor EV mode. In this running mode, the torque that can be output by the second motor 5 is smaller than the output torque of the engine 3, so that a request to increase the driving force (or an acceleration request) is made due to depression of an accelerator pedal (not shown) or the like. Then, the engine 3 is connected to the rear wheel 11 to add the torque of the engine 3 to the torque for traveling. That is, when the engine 3 is stopped, the engine 3 is restarted, and the automatic transmission 1 is switched from the neutral state in which no torque is transmitted to the state in which a predetermined gear stage is set. The control device according to the embodiment of the present invention executes the control of starting the engine 3 and setting the shift speed in the automatic transmission 1 based on the request for increasing the driving force as described below.

FIG. 5 is a flowchart for explaining an example of the control, which is repeatedly executed by the ECU 29 described above while the hybrid vehicle 2 is traveling. Therefore, the ECU 29 corresponds to the controller in the embodiment of the present invention. In the control example shown in FIG. 5, first, it is determined whether or not the automatic transmission 1 is in the neutral state (step S1). This determination can be made on the basis of a command signal to the automatic transmission 1, or can be made on the basis of a signal transmitted from the system for controlling the traveling mode. If a negative determination is made in step S1 because one of the shift stages is set in the automatic transmission 1, the routine shown in FIG. 5 is temporarily terminated without performing any particular control. On the contrary, if the positive determination is made in step S1 because the automatic transmission 1 is in the neutral state, it is determined whether there is a request for increasing the driving force (step S2).

The determination of the driving force increase request in step S2 can be made based on, for example, the accelerator opening degree. If the increase amount is less than a predetermined value even if the accelerator opening degree changes, the determination in step S2 is negative. If the amount of increase in the accelerator opening is equal to or greater than the predetermined value, on the contrary, a positive determination is made in step S2. The reason why the automatic transmission 1 is set to the neutral state while the hybrid vehicle 2 is traveling is that the engine 3 is disconnected from the automatic transmission 1 by not requiring the driving force of the engine 3. In that case, the engine 3 is stopped except when the engine 3 is warmed up or power is generated by the first motor 4. Therefore, in step S2, it may be determined whether or not there is a request to start the engine 3. If the determination in step S2 is negative, the routine of FIG. 5 is once ended without performing any particular control.

On the contrary, if an affirmative determination is made in step S2 due to the request for increasing the driving force, the initial gear stage is calculated (step S3). When the hybrid vehicle 2 is traveling, when the automatic transmission 1 is switched from a neutral state in which no torque is transmitted to a state in which a predetermined gear stage for transmitting torque is set, the torque between the engine 3 and the rear wheels 11 is reduced. By starting transmission, the rotation speed of the engine 3 and the rotation speed of the rotary member of the automatic transmission 1 change. If such a change in the number of revolutions is rapid, a shock occurs and the riding comfort or drivability deteriorates. Further, if the gear stage (gear ratio) to be set is not appropriate, the rotation speed of the engine 3 excessively increases or, conversely, excessively decreases. In order not to cause such an inconvenience, first, the initial shift stage is set. Therefore, the initial shift stage is a shift stage according to the running state determined by the vehicle speed or the like at the present time or a predetermined shift stage. More specifically, the vehicle speed and the accelerator opening may be detected, and the shift speed may be calculated from the detected value and the shift map. Alternatively, a gear speed that is predetermined according to the traveling state or a gear speed that is appropriately determined in terms of design may be used as the initial gear speed. When setting the initial shift stage, it is usual to start the engine 3, so that the initial shift stage is generally a high shift stage.

Then, the control for setting the initial shift speed is started (step S4). In the neutral state, all the engaging mechanisms in the automatic transmission 1 have been released, so the control for engaging the engaging mechanism for setting the initial shift stage among these engaging mechanisms is started. Specifically, the above-described predetermined linear solenoid valves SLK1 to SLB2 are controlled to gradually increase the hydraulic pressure (engagement force or transmission torque capacity) of the engagement mechanism. In the above-described automatic transmission 1, any gear is set by engaging a plurality of engagement mechanisms. Since the torques shared by these engagement mechanisms are different, the order of engagement is predetermined for the purpose of reducing shock and improving the durability of the friction material. Even when setting the initial shift speed, the engagement mechanisms are engaged in a predetermined order.

In parallel with step S1 to step S4, or following step S4, it is determined whether or not there is a downshift request (step S5). The gear stage to be set in the automatic transmission 1 is predetermined according to the vehicle speed, the accelerator opening (requested driving force), and the like. On the other hand, the initial shift stage is set mainly for the purpose of accelerating the start of shift control or improving the shift responsiveness, so that the shift stage satisfying the demand for increasing the driving force is different from the initial shift stage. It is normal to Therefore, in step S5, it is determined whether or not the shift speed that satisfies the driving force increase request is a shift speed lower than the initial shift speed. The shift stage that satisfies the demand for increasing the driving force is, in essence, a shift stage determined from the vehicle speed at that time point, the accelerator opening as a result of depression of the accelerator pedal, and the shift map.

If the determination in step S5 is negative, the control for setting the initial shift stage is continued (step S6). Therefore, finally, the engagement mechanism whose engagement is controlled is controlled to the completely engaged state to set the initial shift stage. On the other hand, if the affirmative determination is made in step S5 due to the downshift request, the engagement mechanism for setting the initial shift stage is in the middle of engagement, and the input rotation speed of the automatic transmission 1 is in progress. It is determined whether or not NT (or engine speed) is a speed (NT≈vehicle speed V×γi) obtained based on the gear ratio γi of the initial shift stage (step S7). The determination in step S7 is, in essence, whether or not the input rotational speed, which was not controlled in the neutral state, can be controlled. Therefore, in addition to determining whether the input rotation speed NT matches the rotation speed determined based on the gear ratio γi, it is determined whether the deviation of those rotation speeds is equal to or less than a predetermined value. Good.

Further, such a change in the rotational speed is caused by an increase in the transmission torque capacity of the engagement mechanism that sets the initial shift stage. Therefore, in step S7, the transmission torque capacity of the engagement mechanism is set to a predetermined torque capacity determined in advance. It may be possible to determine whether or not the above has been reached. In that case, when engaging a plurality of engagement mechanisms whose engagement order is predetermined, it is necessary to determine whether or not the transmission torque capacity of the engagement mechanism that engages last is equal to or greater than a predetermined torque capacity. Good as

Furthermore, since the transmission torque capacity of the engagement mechanism gradually increases with the start of the engagement control (start of hydraulic pressure increase), the elapsed time from the start of the engagement control reaches a predetermined time in step S7. It may be determined whether or not. Even in that case, it may be determined whether or not the elapsed time from the start of the engagement control of the engagement mechanism to be finally engaged has reached a predetermined time.

Furthermore, since the rotation speed of the engine 3 stopped in the neutral state is increased by setting the initial shift speed, the engine rotation speed or the input rotation speed greatly increases at the beginning of control, and the initial shift speed is increased. When the transmission torque capacity of the engagement mechanism that sets is increased and approaches the rotation speed corresponding to the gear ratio γi of the initial shift stage, the increase rate of the rotation speed (rate of change: amount of change per unit time) decreases. Therefore, in step S7, it may be determined whether or not the rate of change of the engine speed or the input speed is less than or equal to a predetermined reference rate of change.

If the determination in step S7 is negative, the conventional control is continued. That is, under the condition that the downshift is requested, the engagement control of the engagement mechanism for setting the initial shift stage is continued. On the other hand, if the determination in step S7 is affirmative, the downshift control is started (step S8). After that, the routine of FIG. 5 is once ended. This downshift is a shift from the above-described initial shift stage to a shift stage determined by a request for increasing driving force, vehicle speed, and the like. Further, to start the downshift control means to start the change of the input rotation speed toward the synchronous rotation speed (the rotation speed obtained based on the gear ratio and the vehicle speed) at the shift stage after the downshift. Specifically, the control for releasing the predetermined engagement mechanism and for engaging the other predetermined engagement mechanism is started. Therefore, since the rotation speed starts to change due to slippage in the disengagement side engagement mechanism, the transmission torque capacity of the disengagement side engagement mechanism is set to a transmission torque capacity that does not cause slip at the initial shift stage, and It is also possible to slip the engagement mechanism on the release side by increasing the transmission torque capacity of the engagement mechanism on the engagement side.

FIG. 3 is a diagram showing changes in the accelerator opening, the gear position, the engine speed Ne corresponding to the input speed of the automatic transmission 1, the longitudinal acceleration G, and the engagement and disengagement states of the engagement mechanism when the above-described control is performed. It is shown in FIG. In the example shown in FIG. 6, the initial shift speed is the sixth speed (6th), the shift speed corresponding to the driving force increase request (acceleration request) is the fifth speed (5th), and the accelerator opening degree is a predetermined opening. This is an example of a state in which the degree is less than or equal to zero (for example, zero), the automatic transmission 1 is in the neutral state with all the engaging mechanisms released, and the engine 3 is stopped and running. In the sixth speed and the fifth speed, as shown in FIG. 4, the first brake B1 maintains the engaged state, so that the description of the change of the first brake B1 is omitted in FIG. Further, in FIG. 6, the broken line for the engine speed “Ne” and the broken line for the acceleration “G” indicate changes in the conventional example shown in FIG. 7, which will be described later, for example.

When the accelerator pedal is depressed at time t1 when the vehicle is traveling with the automatic transmission 1 set to the neutral state, the determination to set the sixth speed as the initial gear is established. The sixth speed is set by engaging the first clutch K1, the fourth clutch K4, and the first brake B1 as shown in FIG. Since the fourth clutch K4 is finally engaged among these engagement mechanisms, the engagement control of the first brake B1 and the first clutch K1 is started at time t2 immediately after time t1. Since these engaging mechanisms are friction type engaging mechanisms that are engaged by hydraulic pressure, first, the supply pressure is temporarily increased in order to close the gap generated in the engaging direction (for packing). A hydraulic control called a fast fill for increasing the pressure is executed, and then the supply pressure is maintained at a predetermined low pressure. That is, the first clutch K1 and the first brake B1 are set to the low pressure standby state in which the ineffective stroke that does not generate the transmission torque capacity is completed and the transmission torque capacity immediately starts to increase due to the increase in the supply pressure.

At time t3 when the first clutch K1 is in the low pressure standby state, the engagement control of the fourth clutch K4 is started. As for the fourth clutch K4, similarly to the first clutch K1, the control of the fast fill and the low pressure standby is continuously performed. The transmission torque capacity of the first clutch K1 is increased immediately after the start of the engagement control of the fourth clutch K4 or almost at the same time as the start of the engagement control with a predetermined gradient, and thereafter, the transmission torque capacity is changed according to the shared torque. The torque capacity (engagement pressure) can be increased. Since the fourth clutch K4 is the last clutch to be engaged, the transmission torque capacity of the fourth clutch K4 is set to a predetermined gradient before and after the first clutch K1 is almost completely engaged. Can be increased gradually.

Since these engagement mechanisms inside the automatic transmission 1 gradually have the transmission torque capacity, the engine speed Ne gradually increases. Then, when the hydraulic pressure of the fourth clutch K4 is gradually increased from the low pressure standby state, the transmission torque capacity of the fourth clutch K4 begins to gradually increase. As a result, the three engaging mechanisms that set the sixth speed, that is, the first clutch K1, the first brake B1, and the fourth clutch K4 all have a transmission torque capacity greater than zero, so the engine speed is increased. Ne almost reaches the synchronous rotation speed at the sixth speed. Along with that, the engine torque is transmitted to the rear propeller shaft 9 via the automatic transmission 1, so that the longitudinal acceleration G starts to increase. In this state, "the input rotational speed of the automatic transmission 1 is determined based on the gear ratio of the initial shift stage while the transmission torque capacity of the engagement mechanism is increasing and before the setting of the initial shift stage is completed. The number has been reached, and therefore the downshift is started at this time (time t4).

The gear set by downshifting is the fifth speed as described above in the embodiment described here. Therefore, the second clutch K2 is engaged instead of the first clutch K1, and the fifth speed is set. To set. Since the downshift from the initial shift stage is a normal power-on downshift from the sixth speed to the fifth speed, it may be controlled in the same manner as the conventionally known clutch-to-clutch shift. Specifically, first, the hydraulic pressure (transmission torque capacity) of the first clutch K1 is stepwise reduced to the extent that slip does not occur, and then the transmission torque capacity is reduced so that the slip amount gradually increases. Since this is a downshift in the power-on state in which the engine 3 is started and outputs torque, the transmission torque capacity of the first clutch K1 decreases and begins to slip, so that the engine speed Ne increases. In that case, torque is consumed to increase the number of rotations of the engine 3 and other rotating members, so that the longitudinal acceleration G decreases.

When the engine speed Ne approaches the synchronous speed of the fifth speed, the transmission torque capacity of the first clutch K1 is slightly increased so as to suppress the increase rate (increase gradient) of the engine speed Ne, and at the same time, the second speed is increased. The hydraulic pressure (transmission torque capacity) of the clutch K2 is increased at a predetermined gradient. As a result, the engine speed Ne smoothly approaches the synchronous speed of the fifth speed, and finally reaches the synchronous speed of the fifth speed. That is, it is possible to prevent or suppress the engine speed Ne from rising, or delaying the convergence of the engine speed Ne to the synchronous speed by fluctuating between the synchronous speeds. On the other hand, since the engagement mechanism for setting the fifth speed has a transmission torque capacity to generate a predetermined reaction force, the driving force increases to the driving force according to the gear ratio of the fifth speed and The acceleration G increases. Thus, the downshift is completed at time t5 when the engine speed Ne reaches the fifth speed synchronous speed and the longitudinal acceleration G reaches the peak value.

In the process of completing the downshift from the initial shift stage in this way, the control device according to the embodiment of the present invention has three engagement mechanisms for setting the initial shift stage, that is, the first clutch K1 and the first brake B1. The downshift control is started before all the fourth clutches K4 are completely engaged. Therefore, the engine speed Ne does not temporarily stall at the synchronous speed of the sixth speed, which is the initial shift stage, during the completion of the fifth speed dow shift. As a result, the time required to achieve the fifth speed is shortened and the acceleration response is improved. In other words, it is possible to avoid or suppress a so-called uncomfortable feeling during acceleration. Further, since the control is performed so as to set the initial shift stage from the neutral state, the engagement mechanism has a predetermined transmission torque capacity in the process, and a reaction force corresponding thereto is generated, so that the longitudinal acceleration G is generated. That is, the driver can experience an increase in the longitudinal acceleration G in the process of producing the longitudinal acceleration G at the shift speed after the downshift, so that the acceleration feeling or the acceleration responsiveness is also improved in this respect.

In the embodiment of the present invention, the first clutch K1 is slipped to start the downshift. Further, in the process of increasing the hydraulic pressure of the first clutch K1 to the hydraulic pressure for complete engagement, the engine speed Ne approaches the synchronous speed of the initial shift stage. Therefore, in the embodiment of the present invention, the transmission torque capacity of the first clutch K1 is maintained at a low capacity as shown by the broken line in FIG. 6 to increase the engine speed Ne, and thereafter the transmission of the fourth clutch K4 is transferred. As the torque capacity increases, the torque applied to the first clutch K1 may increase, causing the first clutch K1 to slip, and thus the downshift may be started.

For comparison, FIG. 7 shows an engine opening corresponding to the accelerator opening, the gear position, and the input speed of the automatic transmission 1 when the downshift to the fifth speed is performed after the setting of the initial gear position is completed. 6 is a time chart showing changes in the number of revolutions Ne, longitudinal acceleration G, and engagement and disengagement states of the engagement mechanism. At time t11, the accelerator pedal is depressed and a request for increasing the driving force is generated. Immediately after that, at t12, the determination for setting the sixth speed is established. In this case as well, similar to the control in the embodiment of the present invention described above, the engagement control of the first brake B1 and the first clutch K1 is performed first, and then the engagement of the fourth clutch K4 to be finally engaged. Combined control is started (at time t13). Around this, the determination of the downshift to the fifth speed is established, but the sixth speed has not yet been achieved, so the engagement control of each engagement mechanism is continued. Then, it is determined that the engine speed Ne has reached the synchronous speed of the sixth speed, and accordingly, the hydraulic pressure of the fourth clutch K4 is increased to the fully engaged hydraulic pressure. In this way, the determination that the initial shift stage has been set is established (time t14), and the downshift control is started immediately after that at time t15. Thereafter, the same control as the downshift in the above-described embodiment of the present invention is executed, and the downshift is completed at time t16.

After all, in the control example for comparison shown in FIG. 7, since the initial shift stage is completely established, the time until the driving force or the acceleration is generated in accordance with the request for increasing the driving force becomes long. .. That is, the acceleration response is inferior.

On the contrary, in order to accelerate the completion of the downshift, an example in which the downshift is executed without performing the setting control of the initial shift stage is shown in FIG. In FIG. 8, the accelerator pedal is depressed at a time point t21, a request for increasing the driving force is generated, and immediately after that, the determination for setting the sixth speed is established at a time point t22. In this case as well, similar to the control in the embodiment of the present invention described above, the engagement control of the first brake B1 and the first clutch K1 is performed first, and then the engagement of the fourth clutch K4 to be finally engaged. Combined control is started (at time t23). Around this, when the determination of downshift to the fifth speed is established, the first clutch K1 is released in the fifth speed, so the first clutch K1 is controlled so as not to have a substantial transmission torque capacity. Also, the engagement control of the second clutch K2 for setting the fifth speed is started. Therefore, while the first brake B1 is engaged, the control for engaging the fourth clutch K4 and the control for engaging the second clutch K2 are advanced in parallel. Meanwhile, the engine speed Ne increases rapidly or uncontrolled due to the power-on state. When the engine speed Ne approaches the synchronous speed of the fifth speed, which is the shift stage after the downshift, or reaches the synchronous speed, the hydraulic pressure (transmission torque capacity) of the second clutch K2 is increased ( (at t24). Further, the engagement pressure of the fourth clutch K4 is increased to the engagement pressure for setting the fifth speed.

In that process, none of the engagement mechanisms has the required transmission torque capacity, and therefore no reaction force is generated, so that the engine speed Ne rises and the longitudinal acceleration G does not occur. Further, since the second clutch K2 starts to have a transmission torque capacity, a predetermined change in the rotational speed of the rotating member occurs, and the driving force is reduced accordingly, so that the longitudinal acceleration G may temporarily decrease.

At the time when the engagement pressure of the fourth clutch K4 is increased, the transmission torque capacity of the second clutch K2 has increased to some extent, so the engine speed Ne decreases toward the fifth speed synchronous speed. When the engine speed Ne reaches the synchronous speed of the fifth speed, the engagement pressure (transmission torque capacity) of the second clutch K2 is increased to a capacity corresponding to the torque shared by the fifth speed ( (at time t25). In that case, since the engine speed Ne is suddenly made to coincide with the fifth-speed synchronous rotation speed, it takes time to converge to the synchronous rotation speed due to twist or slip due to inertial force. Further, the longitudinal acceleration G may vibrate, and the riding comfort or drivability may deteriorate. After all, if the control for setting the initial shift stage is almost not executed as shown in FIG. 8, even if the downshift can be completed at an early stage, the engine speed Ne rises or a shock occurs, and the ride comfort or driver Inconvenience such as deterioration of abilities occurs.

Note that the present invention is not limited to the above-described embodiment, and can be applied to a control device for a vehicle in which an automatic transmission is connected to the output side of a driving force source such as an engine, in addition to a hybrid vehicle. For example, the present invention can be applied to a device that performs control to switch the automatic transmission from a neutral state to a predetermined gear by depressing the accelerator pedal from a state in which the accelerator pedal is returned and coasting (free running).

DESCRIPTION OF SYMBOLS 1... Automatic transmission, 2... Hybrid vehicle, 3... Engine, 4... 1st motor, 5... 2nd motor, 11... Rear wheel, 19... Front wheel, 29... Electronic control unit (ECU), B1... 1st brake , B2... second brake, K1... first clutch, K2... second clutch, K3... third clutch, K4... fourth clutch.

Claims (7)

It has a plurality of engagement mechanisms that can continuously change the transmission torque capacity, and sets a plurality of shift speeds by engaging and releasing the plurality of engagement mechanisms according to the running state of the vehicle, Further, in a control device for an automatic transmission capable of setting a neutral state in which torque is not transmitted by maintaining one of the engagement mechanisms in a released state while the vehicle is traveling,
A controller for controlling the shift of the automatic transmission,
The controller is
Detecting a request for an increase in driving force when traveling while setting the automatic transmission in a neutral state,
When an increase request of the driving force is detected, an initial gear stage to be set in the automatic transmission is obtained, and engagement of an engagement mechanism that is engaged to set the initial gear stage is started,
A rotation speed at which the input rotation speed of the automatic transmission is obtained based on the gear ratio of the initial shift speed while the transmission torque capacity of the engagement mechanism is increasing and before the setting of the initial shift speed is completed. Is determined,
A control device for an automatic transmission, which starts control of a downshift to a shift stage in response to a request to increase the driving force when the determination is satisfied.
The control device for the automatic transmission according to claim 1,
The initial shift stage is one of a predetermined shift stage and a shift stage determined based on the vehicle speed of the vehicle at the time when the request for increasing the driving force is detected. Machine control device.
The control device for the automatic transmission according to claim 1 or 2,
The controller is
The determination that the input speed of the automatic transmission has reached the speed determined based on the gear ratio of the initial gear is that the transmission torque capacity of the engagement mechanism has reached a predetermined torque capacity. A deviation between the input rotation speed of the automatic transmission and the rotation speed obtained from the gear ratio of the initial shift stage and the vehicle speed, since a predetermined time has elapsed since the engagement of the engagement mechanism was started. Has reached a predetermined number of revolutions set in advance and the rate of change of the input number of revolutions of the automatic transmission has become equal to or less than a predetermined reference change rate. Transmission control device.
The control device for the automatic transmission according to claim 3,
The engagement mechanism includes a plurality of engagement-side engagement mechanisms whose engagement order is predetermined.
The fact that the transmission torque capacity of the engagement mechanism has reached a predetermined predetermined torque capacity means that the transmission torque capacity of the engagement side engagement mechanism that is the last in the order of engagement has reached a predetermined predetermined torque capacity. And
The fact that the predetermined time has elapsed from the time when the engagement of the engagement mechanism is started means that the predetermined time has elapsed from the time when the engagement of the last engagement side engagement mechanism is started in the engagement order. A control device for an automatic transmission, characterized in that
The control device for the automatic transmission according to any one of claims 1 to 4,
The automatic transmission further includes a first engagement mechanism that is disengaged at the initial shift stage and engaged at the time of the downshift,
The engagement mechanism controlled to be engaged at the initial shift stage includes a second engagement mechanism released at the time of the downshift,
The controller for an automatic transmission, wherein the controller reduces the transmission torque capacity of the second engagement mechanism to start the downshift.
The control device for the automatic transmission according to any one of claims 1 to 4,
The automatic transmission further includes a first engagement mechanism that is disengaged at the initial shift stage and engaged at the time of the downshift,
The engagement mechanism controlled to engage at the initial shift stage is released at the time of the downshift, and the transmission torque capacity of the first engagement mechanism increases at the initial shift stage to increase the load. A second engagement mechanism for increasing the torque to be applied,
The controller is
The transmission torque capacity of the second engagement mechanism is set to be equal to or less than the shared torque at the initial shift stage,
A control device for an automatic transmission, wherein slippage is caused in the first engagement mechanism by increasing the transmission torque capacity of the first engagement mechanism to start the downshift.
The control device for the automatic transmission according to any one of claims 1 to 6,
The controller of the automatic transmission, wherein the controller releases all of the plurality of engagement mechanisms to set the neutral state.