JP2022114952A - Vehicle drive system control device - Google Patents

Abstract

To provide a vehicle drive system control device capable of expanding a lock-up region and improving fuel economy.SOLUTION: A control device is for a vehicle drive system which comprises: a torque converter provided with a lock-up clutch connected to an engine; a transmission mechanism which outputs rotation of the engine by changing a rotation speed; a shift clutch which is arranged between the torque converter and the transmission mechanism; and a clutch actuator which performs automatic clutch operation. A lock-up clutch control section controls the lock-up clutch so as to allow the same to be disengaged provided that a vehicle speed is equal to or less than a lock-up off speed. The lock-up off speed is changed depending on whether the shift clutch is in an engaged state or disengaged state.SELECTED DRAWING: Figure 4

Description

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

Patent Document 1 discloses a clutch automatic control type vehicle in which a fluid coupling containing a lockup clutch and a wet friction clutch are provided between an engine and a transmission. , which controls disengagement of the wet friction clutch in addition to disengagement of the lockup clutch during sudden braking. According to this automatic clutch control type vehicle, the wet friction clutch is quickly disengaged, thereby preventing engine stall.

JP-A-2002-295669

However, in the vehicle described in Patent Document 1, control is performed so that the lockup clutch is disengaged during braking in order to prevent the engine from stalling, so the lockup region cannot be expanded and fuel efficiency cannot be improved.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control apparatus for a vehicle drive system capable of expanding the lockup region and improving fuel efficiency.

In order to achieve the above objects, the present invention provides a torque converter with a lockup clutch connected to an internal combustion engine, a speed change mechanism for outputting the rotation of the internal combustion engine by shifting it at a gear ratio corresponding to a gear stage, and A speed change clutch provided between a torque converter and the speed change mechanism and switched between an engaged state for transmitting power and a disengaged state for disconnecting power, and a clutch actuator for automatically operating the speed change clutch. A control device for a vehicle drive system, comprising a control unit that controls engagement or disengagement of the lockup clutch, wherein the control unit engages the lockup clutch on condition that the vehicle speed is equal to or lower than a predetermined vehicle speed. The predetermined vehicle speed is controlled to be released, and the predetermined vehicle speed is changed according to whether the shift clutch is in the engaged state or the disengaged state.

According to the present invention, it is possible to provide a control device for a vehicle drive system that can expand the lockup region and improve fuel efficiency.

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 lockup maintenance control processing executed by the control device for the vehicle drive system according to the embodiment of the present invention. FIG. 3 is an example of a timing chart at the time of 1-2 shifting in a vehicle according to a comparative example configured so as not to change the lockup off vehicle speed. FIG. 4 is an example of a timing chart at the time of 1-2 shifting in a vehicle equipped with a control device for a vehicle drive system according to an embodiment of the present invention.

A control device for a vehicle drive system according to an embodiment of the present invention includes a torque converter with a lockup clutch connected to an internal combustion engine, and a gear ratio corresponding to a gear stage for shifting the rotation of the internal combustion engine. A speed change mechanism that outputs an output, a speed change clutch that is provided between the torque converter and the speed change mechanism and that can be switched to an engaged state that transmits power or a disengaged state that interrupts power, and an automatic operation of the speed change clutch. a control device for a vehicle drive system, comprising: a clutch actuator that controls the lockup clutch, the control unit controlling engagement or disengagement of the lockup clutch, wherein the control unit detects that the vehicle speed is equal to or lower than a predetermined vehicle speed; Control is performed to disengage the lockup clutch under certain conditions, and the predetermined vehicle speed is changed according to whether the shift clutch is in the engaged state or the disengaged state. As a result, the control device for a vehicle drive system according to the embodiment of the present invention can expand the lockup region and improve fuel efficiency.

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 engine 2 as an internal combustion engine, an automatic transmission 3 as a vehicle driving device, driving wheels 4 and a control device 10 .

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 .

Automatic transmission 3 is provided in a power transmission path between engine 2 and driving wheels 4 . The automatic transmission 3 has a torque converter 30 , a transmission mechanism 31 , a transmission clutch 32 and a clutch actuator 33 .

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 transmission clutch 32 , transmits power through fluid, and outputs the power to the turbine shaft 36 .

A speed change clutch 32 is connected to the turbine shaft 36 . 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 torque converter 30 is transmitted to transmission mechanism 31 via turbine shaft 36 and 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).

The lockup clutch 35 is provided in the torque converter 30, and is in an engaged state in which the crankshaft 21 and the turbine shaft 36 of the engine 2 are connected so as to integrally rotate and transmit power (hereinafter referred to as "lockup"). and a released state in which the lockup between the crankshaft 21 and the turbine shaft 36 is released and power is transmitted between the crankshaft 21 and the turbine shaft 36 via fluid (working oil). It's like

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 .

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. A shift actuator (not shown) automatically switches 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.

Transmission clutch 32 is provided in a power transmission path between torque converter 30 and transmission mechanism 31 . 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 the clutch disk 32b is pressed against the clutch wheel disk 32a so that the clutch disk 32b rotates integrally with the clutch wheel disk 32a 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 .

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 by a release fork or the like, and elastically deforms the diaphragm spring of the clutch wheel disc 32a by the release bearing 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 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory for storing backup data, an input port, and an output port. computer unit.

The ROM of the computer unit stores a program for causing the computer unit to function as the control device 10 along with various constants, various maps, and the like. That is, the computer unit functions as the control device 10 in this embodiment by the CPU executing the program stored in the ROM using the RAM as a work area.

The control device 10 includes various devices such as the shift actuator (not shown), the clutch actuator 33 and the hydraulic control device 40, 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 speed, which is the rotational speed of the engine 2 (the rotational 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 speed 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, at least 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. 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. 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 torque, which is the torque transmitted by the shift clutch 32, and the clutch position. It has a function as a clutch control unit 101 that controls 32.

The control device 10 functions as a lockup clutch control section 102 that controls engagement or disengagement of the lockup clutch 35 . For example, when a predetermined lockup condition is satisfied, the control device 10 executes lockup control to control the hydraulic control device 40 so as to switch the lockup clutch 35 from the disengaged state to the engaged state. The lockup clutch control section 102 of this embodiment constitutes a control section.

In this embodiment, the predetermined lockup condition is, for example, that the vehicle speed is equal to or higher than a predetermined lockup-on vehicle speed. The predetermined lockup-on vehicle speed is a vehicle speed lower than the vehicle speed defined by the shift line for upshifting from the 1st speed to the 2nd speed (hereinafter referred to as "1-2 shift line") on the shift map. which is experimentally determined in advance and stored in the ROM of the control device 10 . Therefore, in this embodiment, an upshift from the first gear to the second gear is executed after the engagement operation of the lockup clutch 35 is started.

If the shift is executed with the lockup clutch 35 released, the turbine torque is calculated to prevent the shift clutch 32 from suddenly engaging due to the difference between the turbine rotation speed and the clutch rotation speed. and control. However, although the control device 10 of this embodiment can instruct the engine torque, it cannot directly control the turbine torque. For this reason, if the turbine torque is to be controlled, a value obtained by converting the required turbine torque into engine torque must be indicated as an engine torque command value, which increases the complexity of control.

Also, if the lockup clutch 35 is to be engaged during shifting, there are two objects to be controlled: the lockup clutch 35 and the shifting clutch 32 . In this case, it is necessary to consider the interaction between the lockup clutch 35 and the shift clutch 32 and simultaneously control both of them, which makes the control more complicated.

Therefore, in this embodiment, by setting the vehicle speed defined by the 1-2 shift line as described above to a vehicle speed higher than the predetermined lockup-on vehicle speed, it is possible to shift gears in a more stable engagement state of the lockup clutch 35. made it possible to do Further, if the gear shift is performed when the lockup clutch 35 is engaged, the difference between the turbine torque and the engine torque can be ignored, and as a result, the acceleration of the turbine speed is determined by the engine torque and the clutch torque. Furthermore, there is no need to control two clutches at the same time. Therefore, in this embodiment, complication of control can also be avoided.

The predetermined lockup condition is not limited to the conditions described above, and other conditions may be used, and the state of the shift stage and the vehicle speed may be used as the predetermined lockup condition.

That is, the control device 10 locks up (engages) the lockup clutch 35 on condition that the lockup clutch 35 is being released and the vehicle speed changes from below the lockup on vehicle speed to above the lockup on vehicle speed. to control. Conversely, the control device 10 releases the lockup clutch 35 on the condition that the lockup clutch 35 is being engaged and the vehicle speed changes from the lockup off vehicle speed or more to the lockup off vehicle speed or less as a predetermined vehicle speed. It is designed to be controlled so that Note that the lockup on vehicle speed is set to be higher than the lockup off vehicle speed.

In this embodiment, the lock-up off vehicle speed is changed according to whether the shift clutch 32 is in the engaged state or the disengaged state. Specifically, when the lock-up off vehicle speed when the shift clutch 32 is in the engaged state is defined as the first vehicle speed V1, and the lock-up off vehicle speed when the shift clutch 32 is in the disengaged state is defined as the second vehicle speed V2, The second vehicle speed V2 is set to a value lower than the first vehicle speed V1.

The first vehicle speed V1 is a vehicle speed corresponding to an engine speed obtained by adding a predetermined allowance to the idle speed of the engine 2, and is experimentally determined in advance and stored in the ROM of the control device 10. FIG. The second vehicle speed V2 is the engine speed ( For example, it is a vehicle speed corresponding to the idling speed of -300 [rpm], which is experimentally determined in advance and stored in the ROM of the control device 10 . The vehicle speed corresponding to the engine speed is the vehicle speed calculated from the engine speed (engine speed) and the gear ratio (gear ratio) of the power transmission path such as the transmission 3, the dynamic radius of the driving wheels, and the like. be. By using the vehicle speed, even if the speed change clutch 32 is in the disengaged state, it is possible to easily make a judgment considering the engine speed (engine speed) when the lockup clutch 35 and the speed change clutch 32 are in the engaged state. be able to.

The lockup off vehicle speed is set to gradually decrease from the first vehicle speed V1 toward the second vehicle speed V2 when the shift clutch 32 starts switching from the engaged state to the disengaged state. Note that the lockup off vehicle speed may be set to decrease from the first vehicle speed V1 to the second vehicle speed V2 at the timing when switching from the engaged state to the disengaged state of the shift clutch 32 is started.

The lockup off vehicle speed gradually increases from the second vehicle speed V2 toward the first vehicle speed V1 as the clutch torque increases after the shift clutch 32 starts to be switched from the disengaged state to the engaged state. is set to In other words, the lockup off vehicle speed is set to gradually increase from the second vehicle speed to the first vehicle speed when the clutch torque exceeds 0 [Nm]. That is, when torque transmission of the variable speed clutch 32 is started, the lockup off vehicle speed gradually increases from the second vehicle speed to the first vehicle speed.

(Lockup maintenance control)
Next, with reference to FIG. 2, the flow of lockup maintenance control processing executed by the control device 10 of the present embodiment will be described.

As shown in FIG. 2, the control device 10 determines whether or not the vehicle speed exceeds the vehicle speed defined by the 1-2 shift line (simply referred to as "1-2 shift line" in FIG. 2) ( step S1). If the control device 10 determines in step S1 that the vehicle speed does not exceed the vehicle speed defined by the 1-2 shift line, it repeats the processing of step S1.

When the control device 10 determines in step S1 that the vehicle speed exceeds the vehicle speed defined by the 1-2 shift line, it starts shifting (step S2). When gear shifting is started, switching from the engaged state of the gear shift clutch 32 to the disengaged state is started. As a result, the clutch torque of the shift clutch 32 begins to decrease.

Next, the control device 10 reduces the lockup off vehicle speed (step S3). At this time, the lockup off vehicle speed gradually decreases from the first vehicle speed V1 toward the second vehicle speed V2.

After that, the control device 10 determines whether or not the clutch torque of the shift clutch 32 is 0 [Nm] or less (step S4). When the clutch torque becomes 0 [Nm] or less, the variable speed clutch 32 is completely released and is in a disengaged state.

If the control device 10 determines in step S4 that the clutch torque is not 0 [Nm] or less, it repeats the processing of step S4.

When the control device 10 determines in step S4 that the clutch torque is 0 [Nm] or less, the control device 10 maintains the lockup off vehicle speed at the second vehicle speed V2 (step S5). In the present embodiment, the second vehicle speed V2 is set to a predetermined specific value, but this is not restrictive. may be defined as Even in this case, it is preferable that the second vehicle speed V2 be set to an engine speed at which engine stall can be avoided by disengaging the lockup clutch 35 (for example, about idle speed minus 300 [rpm]).

Next, the control device 10 starts switching the transmission clutch 32 from the disengaged state to the engaged state, and determines whether or not the clutch torque exceeds 0 [Nm] (step S6). If the control device 10 determines in step S6 that the clutch torque does not exceed 0 [Nm], it repeats the processing of step S6.

When determining that the clutch torque has exceeded 0 [Nm], the control device 10 increases the lockup off vehicle speed from the second vehicle speed V2 to the first vehicle speed V1 (step S7). At this time, the lockup off vehicle speed gradually increases from the second vehicle speed V2 toward the first vehicle speed V1 as the clutch torque increases.

After that, the control device 10 completes the shift (step S8) and terminates the lockup maintenance control. When the speed change is completed, that is, when the speed change clutch 32 is engaged after the speed change operation is completed, the lockup off vehicle speed becomes the first vehicle speed V1.

Next, referring to FIG. 4, the lockup-off vehicle speed shown in FIG. The description will be made in comparison with a comparative example having an unchanged configuration. 3 and 4 are time charts showing changes in the state of a vehicle that accelerates at a predetermined accelerator opening, and show the shift from 1st speed to 2nd speed from time t3 to time t6, including before and after that. ing.

In FIGS. 3 and 4, the "1-2 shift line" indicates the vehicle speed at which the upshift from the 1st speed to the 2nd speed is performed on the shift map. 3 and 4, the transition of the lockup off vehicle speed in the period from time t3 to time t6 differs between the comparative example and the embodiment, but the transition of other parameters is the same. .

As shown in FIG. 4, the vehicle 1 of this embodiment is accelerating in the first gear at time t1, and the shift clutch 32 is in the engaged state. Since the vehicle is accelerating, the engine rotation speed Ne, the turbine rotation speed Nt, and the clutch rotation speed Nc are increasing over time.

After that, at time t2, when the vehicle speed becomes equal to or higher than the lockup-on vehicle speed, the engagement operation of the lockup clutch 35 is started, and the lockup clutch 35 is switched from the disengaged state to the engaged state. Note that until the lockup clutch 35 is engaged, the rotation of the engine 2 is transmitted through the fluid in the torque converter 30, so there is actually a difference between the engine speed Ne and the turbine speed Nt. However, in FIGS. 3 and 4, the differential rotation is omitted. After the lockup clutch 35 is engaged, the engine speed Ne and the turbine speed Nt are synchronized.

Next, at time t3, when the vehicle speed exceeds the vehicle speed defined by the 1-2 shift line, a shift, that is, an upshift from the 1st speed to the 2nd speed is started. When an upshift from the 1st speed to the 2nd speed is started, switching from the engaged state of the shift clutch 32 to the disengaged state is started. As a result, the clutch torque of the shift clutch 32 begins to decrease.

At time t3, when an upshift from the first gear to the second gear is started, the lockup off vehicle speed gradually decreases from the first vehicle speed V1 toward the second vehicle speed V2.

After that, at time t4, when the clutch torque of the shift clutch 32 becomes 0 [Nm] or less and the shift clutch 32 is completely disengaged, the lockup off vehicle speed is maintained at the second vehicle speed V2 thereafter. It is desirable that the timing at which the lockup-off vehicle speed becomes the second vehicle speed V2 is switched before the clutch torque of the shift clutch 32 becomes 0 [Nm]. That is, the timing for reducing the lockup-off vehicle speed is while the shift clutch 32 is switched from the engaged state to the disengaged state, and the lockup-off vehicle speed is reduced before the shift clutch 32 is completely disengaged and switched to the disengaged state. .

After time t4, the gear pair inside the transmission mechanism 31 is switched, and the gear is switched from the 1st gear to the 2nd gear. As the synchronizing device works to shift to the second gear, the clutch rotation speed Nc begins to decrease as much as possible to the rotation speed corresponding to the vehicle speed. At this time, as a result of the transmission clutch 32 being in the disengaged state, the driving force of the vehicle 1 disappears and the speed of the vehicle 1 also decreases. The engine rotation speed Ne and the turbine rotation speed Nt are controlled so as to decrease so as to synchronize with the clutch rotation speed Nc corresponding to the second gear.

At this time, for example, when the vehicle 1 is traveling on an uphill road or a road surface that causes a decrease in vehicle speed, during the upshift from the first gear to the second gear, the time t4 is reached as a boundary as shown in FIG. In some cases, the vehicle speed begins to decrease significantly.

When such a decrease in vehicle speed occurs, in the comparative example shown in FIG. 3, the lockup-off vehicle speed remains at the first vehicle speed V1 even when an upshift from the first gear to the second gear is started at time t3. Therefore, there is a possibility that the vehicle speed becomes equal to or lower than the lockup off vehicle speed after time t4 when the shift clutch 32 is in the disengaged state. In this case, in the comparative example, the lockup clutch 35 is released unnecessarily, making it impossible to expand the lockup region.

Furthermore, in the case of the comparative example shown in FIG. 3, it is possible to set the 1-2 shift line high in order to avoid unnecessary disengagement of the lockup clutch 35 as described above, thereby making it difficult for the vehicle speed to fall below the lockup off vehicle speed. Conceivable. However, in this case, the engine speed is driven at a high speed while the vehicle is running in the first gear, and the fuel consumption of the engine 2 increases.

On the other hand, in this embodiment, at least after time t4 when the shift clutch 32 is in the disengaged state, the lockup off vehicle speed is reduced from the first vehicle speed V1 to the second vehicle speed V2. Even if the vehicle speed decreases due to traveling on an uphill road or a road surface that causes the vehicle speed to decrease, it is possible to prevent the vehicle speed from becoming equal to or lower than the lockup off vehicle speed after time t4. Therefore, in this embodiment, the lockup clutch 35 is not disengaged during the upshift from the 1st speed to the 2nd speed, and the lockup region can be expanded. Furthermore, since there is no need to set the 1-2 shift line high, it is possible to prevent the fuel consumption of the engine 2 from increasing.

After the time t4 has elapsed, the gear pair switching from the first gear to the second gear is completed inside the transmission mechanism 31, and the clutch rotation speed Nc corresponds to the vehicle speed in the second gear. When the rotational speed reaches 0, switching from the disengaged state to the engaged state of the shift clutch 32 is started, and the clutch torque of the shift clutch 32 exceeds 0 [Nm] at time t5. When torque transmission by the variable speed clutch 32 is started, the lockup off vehicle speed starts to increase. After time t5, the lockup off vehicle speed gradually increases from the second vehicle speed V2 toward the first vehicle speed V1. Moreover, the vehicle speed starts to increase after time t5.

After that, at time t6, when the shift clutch 32 is engaged, the engine speed Ne and the turbine speed Nt are synchronized with the clutch speed Nc corresponding to the second speed, and an upshift is performed from the first speed to the second speed. is completed. When the upshift from the first gear to the second gear is completed at time t6 in this way, the lockup off vehicle speed returns to the first vehicle speed V1. It should be noted that the lockup-off vehicle speed to be returned does not have to be returned to the first vehicle speed V1, and the lockup-off vehicle speed may be set corresponding to the second gear stage. Moreover, it is desirable that the return of the lock-up off vehicle speed to the first vehicle speed V1 be completed at approximately the same timing as the completion of engagement of the shift clutch 32 . In other words, if the shift clutch 32 is being controlled, even if the lockup clutch 35 is not released, the decrease in engine speed caused by the vehicle speed can be dealt with by controlling the shift clutch 32. Release of the lockup clutch 35 is suppressed until completion (end of control).

As described above, the control device for the vehicle drive system according to the present embodiment is configured to perform control so as to release the lockup clutch 35 on condition that the vehicle speed is equal to or lower than the lockup off vehicle speed. In the control device for the vehicle drive system according to the present embodiment, the lock-up off vehicle speed is configured to be changed according to whether the shift clutch 32 is in the engaged state or the disengaged state.

With this configuration, the control device for the vehicle drive system according to the present embodiment can increase or decrease the lockup-off vehicle speed according to the state of the shift clutch 32. Therefore, for example, when the shift clutch 32 is in the disengaged state, the lockup-off vehicle speed can be reduced, and even if the vehicle speed decreases, it is possible to prevent the vehicle speed from becoming equal to or lower than the lockup off vehicle speed. As a result, unnecessary disengagement of the lockup clutch 35 can be prevented, and the lockup region can be expanded. As a result, the control device for the vehicle drive system according to the present embodiment can improve fuel efficiency.

Furthermore, when the shift clutch 32 is in the disengaged state during an upshift from the first gear to the second gear, the locked state of the lockup clutch 35 can be maintained. Large fluctuations are suppressed, and complication of control when engaging the shift clutch 32 can be prevented.

In the control device for the vehicle drive system according to the present embodiment, the lockup-off vehicle speed when the speed change clutch 32 is in the engaged state is the first vehicle speed V1, and the lockup-off speed when the speed change clutch 32 is in the disengaged state is V1. Assuming that the vehicle speed is the second vehicle speed V2, the second vehicle speed V2 is set to a value lower than the first vehicle speed V1.

With this configuration, the control device for the vehicle drive system according to the present embodiment can prevent the vehicle 1 from traveling on an uphill road or a road surface that causes a decrease in vehicle speed during an upshift from the first gear to the second gear. Even if the vehicle speed decreases due to the lockup-off vehicle speed, it is possible to avoid the vehicle speed from becoming equal to or lower than the lockup-off vehicle speed. Therefore, unnecessary disengagement of the lockup clutch 35 can be prevented, and furthermore, since there is no need to set the 1-2 shift line high, it is possible to prevent the fuel consumption of the engine 2 from increasing.

In addition, in the control device for the vehicle drive system according to the present embodiment, the lock-up off vehicle speed changes from the first vehicle speed V1 to the second vehicle speed when switching from the engaged state of the shift clutch 32 to the disengaged state is started. It is configured to gradually decrease toward V2.

With this configuration, the control device for the vehicle drive system according to the present embodiment prevents the lock-up off vehicle speed from being excessively reduced when switching from the engaged state of the shift clutch 32 to the disengaged state, in which the clutch torque is large, starts. can be done. In addition, the lockup off vehicle speed can be decreased in accordance with the decrease in clutch torque. Therefore, it is possible to prevent engine stall from occurring at the start of switching from the engaged state of the shift clutch 32 to the disengaged state, where the clutch torque is large.

In addition, in the control device for the vehicle drive system according to the present embodiment, the lock-up off vehicle speed increases as the clutch torque increases after the shift clutch 32 starts switching from the disengaged state to the engaged state. It is configured to gradually increase from the second vehicle speed V2 toward the first vehicle speed V1.

With this configuration, the control device for the vehicle drive system according to the present embodiment may still cause the vehicle speed to be equal to or lower than the first vehicle speed V1 even when the vehicle speed increases as the clutch torque increases. Even in such a case, it is possible to prevent the vehicle speed from becoming equal to or lower than the lockup off vehicle speed.

Further, in the control device for the vehicle drive system according to the present embodiment, the lockup off vehicle speed is returned to the first vehicle speed V1 when the speed change clutch 32 is engaged after the speed change operation is completed. there is

With this configuration, the control device for the vehicle drive system according to the present embodiment returns to the normal lockup off vehicle speed in a situation where unnecessary disengagement of the lockup clutch 35 does not occur, thereby ensuring engine stall. can be prevented.

In this embodiment, when switching from the engaged state of the shift clutch 32 to the disengaged state is started, the lock-up off vehicle speed gradually decreases from the first vehicle speed V1 toward the second vehicle speed V2. However, the configuration is not limited to this, and the lockup off vehicle speed is reduced from the first vehicle speed V1 to the second vehicle speed V2 at the timing when the shift clutch 32 is in the disengaged state (for example, time t4 in FIG. 4). may be

In this embodiment, the vehicle speed is detected by the vehicle speed sensor 55. However, the present invention is not limited to this. 10 may be used to calculate the vehicle speed.

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 (internal combustion engine)
3 Automatic transmission (vehicle drive system)
4 drive wheel 10 control device 21 crankshaft 30 torque converter 31 speed change mechanism 32 speed change clutch 32a clutch wheel disc 32b clutch disc 33 clutch actuator 35 lockup clutch 36 turbine shaft 37 input shaft 38 output shaft 40 hydraulic control device 50 crank angle sensor 51 Turbine rotation speed sensor 52 Clutch rotation speed sensor 53 Clutch position detection sensor 54 Lockup oil pressure sensor 55 Vehicle speed sensor 56 Accelerator sensor 101 Clutch control unit 102 Lockup clutch control unit (control unit)
V1 First vehicle speed V2 Second vehicle speed

Claims (5)

a torque converter with a lockup clutch connected to the internal combustion engine;
a transmission mechanism for outputting the rotation of the internal combustion engine at a gear ratio corresponding to a gear stage;
a speed change clutch provided between the torque converter and the speed change mechanism and capable of being switched 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 controls engagement or release of the lockup clutch,
The control unit controls to release the lockup clutch on condition that the vehicle speed is equal to or lower than a predetermined vehicle speed,
A control device for a vehicle drive system, wherein the predetermined vehicle speed is changed according to whether the shift clutch is in the engaged state or the disengaged state. Assuming that the predetermined vehicle speed when the speed change clutch is in the engaged state is a first vehicle speed, and the predetermined vehicle speed when the speed change clutch is in the disengaged state is a second vehicle speed,
2. The control device for a vehicle drive system according to claim 1, wherein said second vehicle speed is lower than said first vehicle speed. The predetermined vehicle speed gradually decreases from the first vehicle speed toward the second vehicle speed when switching from the engaged state to the disengaged state of the shift clutch is started. Item 3. A control device for a vehicle drive system according to Item 2. The predetermined vehicle speed changes from the second vehicle speed to the first vehicle speed as the torque transmitted by the shift clutch increases after the shift clutch starts to be switched from the disengaged state to the engaged state. 4. The control device for a vehicle drive system according to claim 2, wherein the speed gradually increases toward the vehicle speed. 5. The predetermined vehicle speed becomes the first vehicle speed when the speed change clutch is in the engaged state after completion of the speed change operation for switching the gear stage of the speed change mechanism. The control device for a vehicle drive system according to any one of claims 1 to 3.

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