JP2022191016A - Control device for vehicle drive apparatus - Google Patents

Abstract

To provide a control device for a vehicle drive apparatus, which can improve responsiveness of a kickdown shift to an acceleration request of a driver.SOLUTION: A control device, when performing a kickdown shift to down-shift a shift stage of a transmission to a predetermined shift stage (YES in Step S1), in a state in which a lock-up clutch is changed to a disengaged state (Step S2), performs changing of the shift stage with changing of a shift clutch (Step S2 to Step S6). The control device, when performing a kick-down shift to down-shift the shift stage of the transmission to a predetermined shift stage, during performing of the kick-down shift, sets a target engine rotation speed which is a target rotation speed of an engine, to be higher than a target turbine rotation speed which is a target rotation speed of a turbine shaft connecting a torque converter and the shift clutch.SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for a vehicle drive system.

In Patent Document 1, a fluid coupling with a built-in lockup clutch and a speed change clutch are interposed between an engine and a transmission, the lockup clutch is disengaged when the vehicle starts moving, and the lockup clutch is engaged after the vehicle starts to shift. A power transmission device provided with a control section for controlling engagement and disengagement of a shift clutch at times, wherein the control section weakens the pressing force of the lock-up clutch engagement until the shift clutch that has been disengaged at the time of shifting is completely connected, and the shift clutch is engaged. It is disclosed that control is performed to increase the pressing force of the lockup clutch engagement to the original state after the clutch is completely engaged. According to the power transmission device described in Patent Document 1, it is possible to reduce the contact shock of the shift clutch while ensuring the durability of the lockup clutch.

JP-A-2003-161368

However, in the power transmission device disclosed in Patent Document 1, the inertia of the torque converter acts on the engine through the lockup clutch whose pressing force is weakened during shifting. Therefore, in the power transmission device described in Patent Document 1, when kickdown is performed to downshift the gear stage of the transmission to the low speed side in response to the driver's acceleration request, the engine rotation speed quickly increases. Therefore, there is a problem that the time from the start to the completion of the kickdown shift becomes long, and the responsiveness of the kickdown shift is not good.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control apparatus for a vehicle drive system capable of improving the responsiveness of a kickdown shift to a driver's acceleration request.

In order to achieve the above object, the present invention comprises an engine, a torque converter with a lockup clutch connected to the engine, and a speed change mechanism for outputting the rotation of the engine by changing the speed ratio according to the gear stage. a speed change clutch provided between the torque converter and the speed change mechanism and capable of switching between an engaged state for transmitting power and a disengaged state for disconnecting power; a clutch actuator for automatically operating the speed change clutch; The control device for a vehicular drive system comprising When the gear stage is downshifted to a predetermined gear stage, the gear stage is changed by switching the gear shift clutch while the lockup clutch is switched to the released state.

Advantageous Effects of Invention According to the present invention, it is possible to provide a control device for a vehicle drive system that can improve the responsiveness of a kickdown shift to a driver's acceleration request.

FIG. 1 is a schematic configuration diagram of a vehicle provided with a control device for a vehicle drive system according to an embodiment of the present invention. FIG. 2 is a flow chart showing the flow of kickdown shift operation by the controller for the vehicle drive system according to the embodiment of the present invention. FIG. 3 is a timing chart showing the transition of the vehicle state when the kickdown shift is performed by the control device for the vehicle drive system according to the embodiment of the present invention. FIG. 4 is a timing chart showing the transition of the vehicle state when the kickdown shift is performed by the control device for the vehicle drive system of the comparative example.

A control device for a vehicle drive system according to an embodiment of the present invention includes an engine, a torque converter with a lockup clutch connected to the engine, and a gear ratio corresponding to a gear stage. A transmission mechanism that outputs output, a transmission clutch that is provided between the torque converter and the transmission mechanism and that can switch between an engaged state that transmits power and a disengaged state that cuts off power, and a clutch actuator that automatically operates the transmission clutch. and a control device for a vehicular drive system, comprising a control unit that implements a kickdown shift that downshifts a gear stage in response to a driver's acceleration request, wherein the control unit implements the kickdown shift. When the gear stage is downshifted to a predetermined gear stage, the gear stage is changed by switching the shift clutch while the lockup clutch is switched to the released state. As a result, the control device for the vehicle drive system according to the embodiment of the present invention can improve the responsiveness of the kickdown shift to the driver's acceleration request.

A vehicle equipped with a control device for a vehicle drive system according to an embodiment of the present invention will now be described with reference to the drawings.

As shown in FIG. 1, a vehicle 1 includes an internal combustion engine 2, a torque converter 30 connected to the engine 2, a transmission 3, driving wheels 4, a control device 10, and an engine controller 20. , is composed of The engine 2, the transmission 3 and the torque converter 30 constitute a vehicle drive system of the present invention.

A plurality of cylinders are formed in the engine 2 . In this embodiment, the engine 2 is constructed so that each cylinder performs a series of four strokes consisting of an intake stroke, a compression stroke, an expansion stroke and an exhaust stroke. The engine 2 is the power source of the vehicle 1 .

A transmission 3 is provided in a power transmission path between the engine 2 and the drive wheels 4 . The transmission 3 has a transmission mechanism 31, a transmission clutch 32, a clutch actuator 33, and a shift actuator (not shown). The transmission 3 is an automatic transmission in which a clutch actuator 33 and a shift actuator are controlled by the control device 10 to automatically change the gear position of the transmission mechanism 31 and change the state of the shift clutch 32. is. In this embodiment, the transmission 3 is an AMT (Automated Manual Transmission) that automates the speed change operation based on the configuration of a parallel shaft gear type stepped manual transmission.

The torque converter 30 is a torque converter with a lockup clutch having a lockup clutch 35 . The torque converter 30 is provided in a power transmission path between the engine 2 and the variable speed clutch 32 , transmits power via fluid, and outputs torque (driving force) input from the crankshaft 21 to the turbine shaft 36 . . Thus, torque converter 30 is provided between engine 2 and transmission 3 .

A speed change clutch 32 is connected to the turbine shaft 36 . In other words, the turbine shaft 36 connects the torque converter 30 and the transmission clutch 32 . The torque converter 30 amplifies the torque (driving force) input from the crankshaft 21 of the engine 2 by the rotation difference through the fluid and outputs it to the turbine shaft 36 and the transmission clutch 32 . The output of the torque converter 30 is transmitted to the transmission clutch 32 via the turbine shaft 36 and transmitted to the transmission mechanism 31 via the transmission clutch 32 .

The interior of the torque converter 30 is divided into an apply chamber and a release chamber (not shown) with the lockup clutch 35 as a boundary. Hydraulic oil is supplied to the apply chamber or the release chamber, and the operating state of the lockup clutch 35 is switched according to the hydraulic pressure of the supplied hydraulic oil (working hydraulic pressure).

Lockup clutch 35 is provided within torque converter 30 . The lock-up clutch 35 is connected (hereinafter referred to as “direct connection”) so that the crankshaft 21 and the turbine shaft 36 of the engine 2 rotate integrally to transmit power. The operating state can be switched between a released state in which the direct connection between the crankshaft 21 and the turbine shaft 36 is disengaged and power transmission is performed between the crankshaft 21 and the turbine shaft 36 via fluid (operating oil).

The lockup clutch 35 is switched to the engaged state by supplying working oil pressure (hereinafter, this working oil pressure is referred to as "engagement oil pressure") to the apply chamber and discharging the working oil from the release chamber. Conversely, the lockup clutch 35 is switched to the released state by supplying operating oil pressure (hereinafter, this operating oil pressure is referred to as “releasing oil pressure”) to the release chamber and discharging the operating oil from the apply chamber.

The transmission mechanism 31 is provided in a power transmission path between the transmission clutch 32 and the drive wheels 4, and includes an input shaft 37 connected to the transmission clutch 32 and an output shaft connected to the drive wheels 4 via a differential (not shown). 38 and . The transmission mechanism 31 converts the driving force input from the transmission clutch 32 to the input shaft 37 , changes the rotational speed, and outputs the converted driving force from the output shaft 38 . In this manner, the transmission mechanism 31 shifts the rotation transmitted from the engine 2 via the torque converter 30 at a gear ratio corresponding to the gear stage and outputs the rotation.

The transmission mechanism 31 shifts the rotation of the engine 2, which is output from the engine 2 and transmitted to the input shaft 37, at a transmission gear ratio corresponding to one of a plurality of transmission stages, which will be described later, and outputs the rotation. Output to axis 38 . The rotation and driving force output to the output shaft 38 are transmitted to the driving wheels 4 via a differential (not shown).

The transmission mechanism 31 is configured to be capable of forming a plurality of gear stages with different gear ratios by a plurality of gear pairs with different gear ratios. The transmission mechanism 31 has a synchronization mechanism (synchromesh) (not shown), and the synchronization mechanism performs synchronization at the gear stage to be switched to. A shift actuator (not shown) automatically changes gears in the transmission mechanism 31 . Specifically, the control device 10 refers to a shift map based on the vehicle speed and the amount of depression of the accelerator pedal to determine whether or not a shift is necessary, and outputs a shift instruction to the shift actuator. Then, the shift actuator that receives the gear shift instruction operates to perform the gear shift.

The shift clutch 32 is provided in a power transmission path between the torque converter 30 and the transmission mechanism 31, and switches the power transmission between the torque converter 30 and the transmission mechanism 31 between an engaged state and a disconnected state. The transmission clutch 32 has a clutch wheel disk 32a connected to rotate integrally with the turbine shaft 36, and a clutch disk 32b connected to an input shaft 37 of the transmission mechanism 31 to rotate integrally.

The transmission clutch 32 is a dry single-plate clutch, and when the clutch disk 32b is pressed against the clutch wheel disk 32a, the clutch disk 32b and the clutch wheel disk 32a rotate integrally to transmit power. is separated from the clutch wheel disc 32a to cut off power transmission between the clutch wheel disc 32a and the clutch disc 32b. That is, the transmission clutch 32 transmits power between the turbine shaft 36 and the input shaft 37 in the engaged state, and cuts off the power transmission between the turbine shaft 36 and the input shaft 37 in the disengaged state.

An operation of switching between the engaged state and the disengaged state of the transmission clutch 32 (hereinafter referred to as “clutch operation”) is automatically performed by the clutch actuator 33 . In this manner, the shift stage of the transmission 3 is changed by the clutch operation by the clutch actuator 33 and the shift stage change operation by the shift actuator (not shown).

The clutch actuator 33 is electrically connected to the control device 10 and operates the shift clutch 32 based on commands from the control device 10 . Specifically, the clutch actuator 33 moves a release bearing (not shown) in the axial direction of the input shaft 37 using a release fork or the like, and the release bearing elastically deforms the diaphragm spring of the clutch wheel disc 32a to shift the transmission clutch. 32 is set to the cut-off state. Further, the clutch actuator 33 moves the release bearing from the disengaged position to the disengaged position in the direction opposite to the disengaged position, releases the diaphragm spring from elastic deformation, and engages the transmission clutch 32 .

The control device 10 and the engine controller 20 each include a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data and the like, an input port, A computer unit with an output port.

The ROMs of these computer units store programs for causing these computer units to function as the control device 10 and the engine controller 20 along with various constants and various maps. That is, these computer units function as the control device 10 and the engine controller 20 in this embodiment by the CPU executing the programs stored in the ROM using the RAM as a work area.

The control device 10 includes various devices such as the shift actuator, the clutch actuator 33, and the hydraulic control device 40 (not shown), a crank angle sensor 50, a turbine rotation speed sensor 51, a clutch rotation speed sensor 52, a clutch position detection sensor 53, a lock Various sensors such as an up oil pressure sensor 54, a vehicle speed sensor 55 and an accelerator sensor 56 are connected.

The hydraulic control device 40 controls hydraulic pressure supplied to the lockup clutch 35 and the clutch actuator 33 of the torque converter 30 . The hydraulic control device 40 switches the lockup clutch 35 between the engaged state and the released state by adjusting the magnitude of the hydraulic pressure supplied to the lockup clutch 35 based on the command from the control device 10 . The hydraulic control device 40 adjusts the magnitude of the hydraulic pressure supplied to the clutch actuator 33 based on a command from the control device 10, thereby switching the transmission clutch 32 between the engaged state and the disengaged state.

The crank angle sensor 50 detects the rotation angle of the crankshaft 21 (hereinafter referred to as "crank angle"). The control device 10 calculates the engine rotation speed, which is the rotation speed of the engine 2 (the rotation speed of the crankshaft 21), based on information indicating the crank angle input from the crank angle sensor 50. FIG.

The turbine rotation speed sensor 51 detects the rotation speed of the turbine shaft 36 (hereinafter referred to as "turbine rotation speed"). The clutch rotation speed sensor 52 detects the rotation speeds of the clutch disk 32b and the input shaft 37 (hereinafter referred to as "clutch rotation speed").

The clutch position detection sensor 53 detects the position of the release bearing in the transmission clutch 32 or the position of a component such as a release fork that moves in relation to the movement state of the release bearing (hereinafter referred to as "clutch position"). The clutch position also indicates the state of the shift clutch 32 (disengaged state/half-clutch state/engaged state), and can also be considered to indicate the magnitude of torque transmitted by the shift clutch 32 . A lockup oil pressure sensor 54 detects the operating oil pressure supplied to the lockup clutch 35 . In this embodiment, it is assumed that the engagement hydraulic pressure acting on the apply chamber is detected, but the hydraulic pressure acting on the apply chamber may be estimated or detected based on the release hydraulic pressure acting on the release chamber. The up oil pressure sensor 54 may not be provided. A vehicle speed sensor 55 detects the vehicle speed, which is the speed of the vehicle 1 . An accelerator sensor 56 detects the amount of depression of an accelerator pedal (not shown) by the driver. Therefore, the accelerator sensor 56 detects the driver's request for acceleration. Note that the accelerator sensor 56 may detect movement of the throttle valve that changes in conjunction with the depression amount of the accelerator pedal.

Based on the clutch position detected by the clutch position detection sensor 53, the control device 10 refers to a map (not shown) that defines the relationship between the clutch position and the clutch transmission torque (hereinafter also referred to as "clutch torque"). It has a function as a clutch control unit 101 that controls the shift clutch 32, specifically, controls the clutch actuator 33 so that the shift clutch 32 is operated. The control device 10 of this embodiment constitutes a control unit in the present invention.

In the case of performing normal gear shifting during running after the vehicle 1 has started, the control device 10 switches the speed change clutch 32 from the engaged state to the disengaged state, and then changes the gear position in the speed change mechanism 31 . Clutch operation and shift operation are automatically performed by controlling the clutch actuator 33 and the shift actuator so as to switch from the disconnected state to the engaged state. A normal shift is, for example, an upshift from 4th to 5th for gentle acceleration or a downshift from 4th to 3rd for gentle deceleration. The control device 10 maintains the lockup clutch 35 in the engaged state when carrying out such normal shifting.

Here, the control device 10 implements a kick-down gear shift for down-shifting the gear stage of the transmission 3 in response to the driver's acceleration request. Specifically, when the driver's acceleration request is large and the amount of depression of the accelerator pedal exceeds a predetermined value, the control device 10 performs a kickdown shift. The kickdown shift is a shift that downshifts the gear stage of the transmission 3 to a gear stage on the low speed side to increase the reduction ratio, increases the engine rotation speed, increases the driving force, and greatly accelerates the vehicle 1. .

When performing a kickdown shift, the control device 10 first switches the shift clutch 32 in the transmission 3 to the released state. Next, the control device 10 changes (downshifts) from the current gear stage to a lower gear stage. Specifically, the control device 10 releases the currently established gear stage to place the transmission 3 in a neutral state, and then controls the shift actuator to establish the downshift destination gear stage. At this time, the synchronizing mechanism of the transmission mechanism 31 is actuated to complete synchronization so that the rotation of the input shaft 37 (rotation of the clutch disc 32b) reaches a rotational speed corresponding to the downshift destination gear stage and vehicle speed. . After that, the control device 10 controls the clutch actuator 33 so as to switch the transmission clutch 32 to the engaged state. Simultaneously with these controls in the transmission 3, control for increasing the engine speed is performed.

Therefore, in order to quickly complete the kickdown shift, it is necessary to quickly complete the synchronization at the downshift destination gear stage. In order to quickly complete the engagement of the shift clutch 32 that is performed after synchronization, the engine rotation speed is quickly increased to an engine rotation speed at which the engagement operation of the shift clutch 32 can be started (hereinafter referred to as the synchronous rotation speed). There is a need. In order to quickly increase the engine rotation speed, it is preferable to prevent the inertia (inertia mass) of the torque converter 30 from acting on the engine 2 during the kickdown shift. If the lockup clutch 35 is maintained in the engaged state during the kickdown shift, the inertia (inertial mass) of the torque converter 30 acts on the engine 2, so the engine rotation speed must be quickly increased to the synchronous rotation speed. cannot be raised. That is, when the lock-up clutch 35 is maintained in the engaged state, the turbine shaft 36 and the clutch wheel disc 32a are directly connected to the crankshaft 21, so their inertia (inertia mass) contributes to the rotation of the crankshaft 21. As a result, the engine rotation speed cannot be quickly increased to the synchronous rotation speed during the kickdown shift.

In this embodiment, as means for quickly increasing the turbine rotation speed during kickdown, the lockup clutch 35 is released and the engine rotation speed is raised first. like. In order to quickly complete the engagement of the transmission clutch 32 that is performed after synchronization in the downshift destination gear stage, the turbine rotation speed is quickly increased from the start of the engagement operation of the transmission clutch 32 to the turbine rotation speed that is completed. need to let In order to quickly increase the turbine rotation speed using the rotational force of the clutch disk 32b, it is preferable to prevent the inertia (inertial mass) of the engine 2 from acting on the torque converter 30 during the kickdown shift. . If the lockup clutch 35 is maintained in the engaged state during the kickdown shift, the inertia (inertia mass) of the engine 2 acts on the torque converter 30, so the turbine rotation speed must be quickly increased to the synchronous rotation speed. cannot be raised. That is, when the lockup clutch 35 is maintained in the engaged state, the crankshaft 21 is directly connected to the turbine shaft 36, so their inertia (inertia mass) suppresses the increase in the rotation speed of the turbine shaft 36. As a result, the turbine rotation speed cannot be quickly increased to the synchronous rotation speed during the kickdown shift.

Therefore, in the present embodiment, when the kickdown shift is performed and the shift speed of the transmission 3 is downshifted to a predetermined shift speed, the control device 10 shifts gears while the lockup clutch 35 is switched to the released state. The shift stage is changed with the switching of the clutch 32 . The predetermined gear stage referred to here is a low gear stage set to a relatively large speed reduction ratio such as used for starting the vehicle. In addition, if the gear stages of the transmission mechanism 31 are divided in order of the reduction ratio, a low speed stage (also called a starting gear stage), which is a gear stage for low-speed running including starting, a middle speed stage (a middle speed stage between the low speed stage and the high speed stage). gear), and a high-speed gear, which is a gear for high-speed running.

The predetermined gear stage includes, for example, the 1st gear stage, which is the gear stage on the low speed side with the largest gear ratio, and the 2nd gear stage, which has the next largest gear ratio after the 1st gear gear, as the starting gear gear to start the vehicle. (used when the road surface has low friction, etc.), the second speed is included in addition to the first speed.

When the vehicle 1 is started using the starting gear, the control device 10 controls the lockup clutch 35 to be in the released state, and torque amplification in the lockup clutch 35 generates a large driving force. In addition, in a medium-to-high speed gear stage that is not a starting gear stage, the control device 10 controls the lockup clutch 35 to be in the engaged state to prevent deterioration of fuel consumption due to slippage of the lockup clutch 35 .

Further, in the present embodiment, when the control device 10 implements a kickdown shift and downshifts the shift stage of the transmission 3 to a predetermined shift stage, the control device 10 controls the target rotation speed of the engine 2 during the kickdown shift. is set higher than the target turbine rotation speed, which is the target rotation speed of the turbine shaft that connects the torque converter 30 and the transmission clutch 32 .

Next, the kickdown shift operation of the control device 10 according to the present embodiment will be described with reference to FIG.

In step S1, the control device 10 determines whether or not there is a request for kickdown shift. Here, when the driver's request for acceleration based on the amount of depression of the accelerator pedal is greater than a predetermined value, the controller 10 determines that there is a request for kickdown shift. It should be noted that the presence or absence of a kickdown shift request can be determined by referring to the presence or absence of a brake operation by the driver and a downshift operation using a shift lever or the like, in addition to the amount of depression of the accelerator pedal. A request for a kickdown shift can be determined in consideration of the brake operation and the downshift operation.

The control device 10 performs a kickdown shift when there is a request for a kickdown shift. The kickdown shift consists of steps S2 to S10 below.

The control device 10 issues an instruction to release the lockup clutch 35 and an instruction to release the shift clutch 32 in step S2. Upon receipt of the release instruction, release of the lockup clutch 35 and the shift clutch 32 is started.

Next, in step S3, the control device 10 repeats the determination (waits for the condition to be satisfied) until the shift clutch torque ≤ 0 [Nm]. The control device 10 starts the gear shift in step S4 when the shift clutch torque≦0 [Nm]. This gearshift is a downshift to a lower gear than the current gear. That is, step S3 is a step for confirming that the transmission clutch 32 has been completely disengaged, and when the driving force is being transmitted, the transmission mechanism 31 is disengaged (the currently established gear stage is changed). release to put the transmission 3 in a neutral state) to prevent the occurrence of shock.

In step S5, the control device 10 repeats determination until the gear shift started in step S4 is completed and the turbine rotation speed, which increases as the engine rotation speed increases, satisfies the relation of turbine rotation speed≧target rotation speed. (Wait for conditions to be met). In other words, in step S5, it is determined whether or not the gear shift clutch 32 is ready to be engaged, and the time to start engaging the gear shift clutch 32 is determined.

If the determination in step S5 is YES, the control device 10 proceeds to step S6, and instructs to engage the shift clutch 32 in step S6. As a result, the transmission clutch 32 starts to be engaged.

Next, in step S7, the control device 10 repeats the determination until the turbine rotation speed is equal to the synchronous rotation speed. The synchronous rotation speed is the rotation speed of the input shaft 37, which is calculated from the gear ratio of the gear stage of the shift destination, the vehicle speed, etc., and is the rotation speed of the clutch disc 32b. In other words, the turbine rotational speed and the rotational speed of the clutch disk 32b become the same, it is determined that the engagement of the speed change clutch 32 is complete, and the time to start engagement of the lockup clutch 35 is determined.

When the turbine rotation speed becomes equal to the synchronous rotation speed in step S7, the control device 10 proceeds to step S8, and instructs to engage the lockup clutch 35 in step S8. As a result, the lockup clutch 35 starts to be engaged.

In step S9, the control device 10 repeats the determination until the turbine rotation speed equals the engine rotation speed.

When the turbine rotation speed equals the engine rotation speed in step S9, the control device 10 determines that the engagement of the lockup clutch 35 is completed in step S10.

In step S11, the control device 10 determines that the kickdown shift operation has been completed, and terminates the current operation.

2 (see FIG. 3), and a comparative example in which the kickdown shift operation is performed while the lockup clutch 35 is maintained in the engaged state (see FIG. 4). , the transition of the vehicle state will be described.

FIG. 3 is a timing chart showing the transition of the vehicle state when the kickdown shift operation of the present embodiment shown in FIG. 2 is performed. The vehicle is running at a constant vehicle speed in the medium speed stage or the high speed stage.

In FIG. 3, at time t1, a kickdown shift is requested (for example, the accelerator pedal is strongly depressed), and kickdown shift is started. At this time t1, an instruction to release the lockup clutch 35 and an instruction to release the shift clutch 32 are issued.

Thereafter, at time t2, disengagement of the lockup clutch 35 is completed. When the release of the lockup clutch 35 is completed, the inertia (inertia mass) of the power transmission path from the turbine shaft 36 onwards on the engine 2 is reduced, so that the engine rotation speed starts to rise quickly.

Thereafter, at time t3, disengagement of the shift clutch 32 is completed. When the shift clutch 32 is completely released, the turbine shaft 36 is separated from the input shaft 37 and the rotation of the crankshaft 21 is transmitted through the fluid (working oil) to start increasing the turbine rotation speed. Further, after the shift clutch 32 is released, the gear position is changed (downshifted), so the clutch rotational speed increases to the rotational speed corresponding to the gear position after the change with respect to the vehicle speed. As shown in FIG. 3, the acceleration of clutch rotation is made larger than the acceleration of turbine rotation, and the downshift in the transmission mechanism 31 is completed in a short period of time. Further, the acceleration of turbine rotation is made relatively gentler than the acceleration of clutch rotation, thereby facilitating control of the engine rotation speed. As shown in FIG. 3, there may be a moment when the clutch rotation speed exceeds the turbine rotation speed during the kickdown shift. As a result, the rotational speed of the turbine shaft 36 can be increased.

After that, at time t4, the engine rotation speed reaches the maximum value (target engine rotation speed), and engagement of the transmission clutch 32 (synchronization between the turbine shaft 36 and the clutch disc 32b) is started. At this time, the engine rotation speed is controlled so as to be maintained at the target engine rotation speed. The rotation speed of 36 is approaching.

Focusing on the turbine rotation speed in this state, at time t4, the turbine rotation speed reaches the target turbine rotation speed, and engagement of the variable speed clutch 32 (synchronization between the turbine shaft 36 and the clutch disc 32b) is started. After that, the turbine rotation speed is greatly reduced by the clutch disk 32b, so that the turbine rotation speed reaches the maximum value at time t4.

After that, at time t5, synchronization of the shift clutch 32 is completed. When the transmission clutch 32 is completely synchronized, the turbine rotation speed and the clutch rotation speed become equal. At time t5, an instruction to engage the lockup clutch 35 is issued in response to the completion of engagement of the speed change clutch 32 (synchronization between the turbine shaft 36 and the clutch disc 32b). Then, the turbine rotation speed and the clutch rotation speed increase to become equal to the engine rotation speed by the power of the engine 2 transmitted via the torque converter 30 . In other words, after time t5 when the shift clutch 32 is engaged, the vehicle speed starts to increase in earnest. At this time, the engine rotation speed is controlled to be slightly higher than when the shift clutch 32 is engaged.

Thereafter, at time t6, engagement of the lockup clutch 35 is completed, and a series of operations constituting the kickdown shift are completed. After that, the engine rotation speed is controlled according to the accelerator operation. In the example shown in FIG. 3, the engine speed increases and the vehicle continues to accelerate.

FIG. 4 is a timing chart showing the transition of the vehicle state of the comparative example in the case of changing the gear stage while the lockup clutch 35 is maintained in the engaged state. is in a closed state.

In FIG. 4, at time t11, there is a request for a kickdown shift, and an instruction to release the shift clutch 32 is issued.

Thereafter, at time t12, disengagement of shift clutch 32 is completed.

After that, at time t13, the engine rotation speed reaches the maximum value (target engine rotation speed), and synchronization of the shift clutch 32 is started.

After that, at time t14, synchronization of the shift clutch 32 is completed.

As described above, in the comparative example of FIG. 4, when the kickdown shift is requested at time t11, the lockup clutch 35 is maintained in the engaged state, so that the engine rotation speed can quickly increase. Can not. Therefore, the timing at which the engine rotation speed reaches the maximum value (target engine rotation speed) at time t13 is delayed, and the timing at which the synchronization of the shift clutch 32 is completed is delayed. Therefore, the time required from the start to the completion of the kickdown shift becomes longer. Therefore, in the comparative example of FIG. 4, the responsiveness of the kickdown shift is inferior.

As described above, in this embodiment, when the control device 10 implements a kickdown shift and downshifts the gear stage of the transmission 3 to a predetermined gear stage, the lockup clutch 35 is switched to the released state. , the shift stage is changed with the switching of the shift clutch 32 .

With this configuration, the lock-up clutch 35 is switched to the released state during a shift stage change involving switching of the shift clutch 32, and the inertia torque on the turbine shaft side of the torque converter 30 does not act on the engine 2. , the engine rotation speed can be quickly increased to the target rotation speed corresponding to the gear stage after shifting.

If the engine speed is increased in advance, the inertia torque of the engine 2 will not act on the torque converter 30 when the turbine speed is increased after the shift clutch 32 is released. Therefore, the turbine rotation speed can be quickly increased to the target turbine rotation speed. In other words, by releasing the lockup clutch, the engine speed was quickly increased before the shift clutch was released. (because the inertia of the engine does not act), the shift time can be shortened.

Therefore, the time required for gear shifting can be shortened, and the torque discontinuity time during gear shifting can be shortened.

In addition, by utilizing the amplifying action of the torque converter 30 that accompanies the increase in the engine speed, powerful acceleration becomes possible.

As a result, it is possible to improve the responsiveness of the kickdown shift to the driver's acceleration request.

Further, in the present embodiment, when the control device 10 implements a kickdown shift and downshifts the shift stage of the transmission 3 to a predetermined shift stage, the control device 10 controls the target rotation speed of the engine 2 during the kickdown shift. is set higher than the target turbine rotation speed, which is the target rotation speed of the turbine shaft that connects the torque converter 30 and the transmission clutch 32 .

With this configuration, the rotation of the engine 2 is transmitted to the turbine shaft via the working fluid of the torque converter 30 and the turbine rotation speed increases so as to approach the engine rotation speed during the kickdown shift. can be hastened and the time required for shifting can be shortened.

Further, in this embodiment, the predetermined gear stage is a starting gear stage used for starting the vehicle.

With this configuration, when a kickdown shift to a starting shift stage such as the first speed stage is performed because the driver's acceleration request is large, the shift clutch 32 is switched while the lockup clutch 35 is switched to the released state. Since the shift stage is changed along with the acceleration, the acceleration expected by the driver can be realized, and the responsiveness of the kickdown shift to the driver's acceleration request can be improved.

In addition, when the driver's acceleration request is not large and a kickdown shift to a shift stage other than the start shift stage is performed, the shift gear shift involving switching of the shift clutch 32 is performed while the lockup clutch 35 is maintained in the engaged state. is changed, it is possible to suppress deterioration of fuel consumption due to slippage of the working fluid of the torque converter 30 .

Although embodiments of the present invention have been disclosed, it will be apparent that modifications may be made by those skilled in the art without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

1 vehicle 2 engine 3 transmission 10 control device (control unit)
30 torque converter 31 transmission mechanism 32 transmission clutch 33 clutch actuator (actuator)
35 lockup clutch 36 turbine shaft

Claims (3)

engine and
a torque converter with a lockup clutch connected to the engine;
a speed change mechanism that shifts and outputs the rotation of the engine at a speed ratio corresponding to a gear stage;
a transmission clutch provided between the torque converter and the speed change mechanism and capable of switching between an engaged state for transmitting power and a disconnected state for disconnecting power;
a clutch actuator that automatically operates the shift clutch;
A control device for a vehicle drive system comprising
A control unit that implements a kickdown shift that downshifts the gear stage in response to a driver's acceleration request,
The control unit
When performing the kickdown shift and downshifting the gear stage to a predetermined gear stage,
A control device for a vehicular drive system, wherein the shift stage is changed by switching the shift clutch while the lockup clutch is switched to a released state. The control unit
When performing the kickdown shift and downshifting the gear stage to the predetermined gear stage,
During the kickdown shift, a target engine rotation speed, which is a target rotation speed of the engine, is set higher than a target turbine rotation speed, which is a target rotation speed of a turbine shaft connecting the torque converter and the transmission clutch. 2. The control device for a vehicle drive system according to claim 1, wherein: 3. The control device for a vehicle drive system according to claim 1, wherein the predetermined gear stage is a starting gear stage used for starting the vehicle.

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