Control device for vehicle driving device

1. A control device for controlling a vehicle driving device provided with a transmission apparatus including a plurality of engagement devices in a power transmission path between a driving force source and a wheel and selectively forming a plurality of transmission shift stages having different transmission shift ratios depending on engagement states of the plurality of engagement devices, the control device comprising:

an electronic control unit that includes control logic, which when executed:

starts upshift control for switching to a transmission shift stage having a lower transmission shift ratio,

performs torque phase control for increasing an engagement pressure of an engagement side engagement device to be engaged for the switching to the transmission shift stage, the engagement side engagement device being one of the plurality of engagement devices, and reducing an engagement pressure of a release side engagement device to be released for the switching to the transmission shift stage, the release side engagement device being one of the plurality of engagement devices, and

performs inertia phase control for increasing a rotation speed difference of the release side engagement device and reducing a rotation speed difference of the engagement side engagement device to perform a rotation change after starting the torque phase control,

wherein the electronic control unit performs torque down control for reducing a torque of the driving force source in the inertia phase control and changes a start timing of the torque down control relative to an execution timing of the torque phase control according to at least a pre-transmission shift torque, which is the torque of the driving force source before starting the upshift control.

2. The control device for a vehicle driving device according to claim 1 , wherein the electronic control unit delays the start timing of the torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner as the pre-transmission shift torque is reduced.

3. The control device for a vehicle driving device according to claim 1 , wherein the electronic control unit reduces a reduction speed of a torque of the driving force source in the torque down control continuously or in a stepwise manner as the pre-transmission shift torque is reduced.

4. The control device for a vehicle driving device according to claim 1 , wherein, after starting the inertia phase control, the electronic control unit performs engagement pressure increase control for temporarily increasing the engagement pressure of the engagement side engagement device and changes a temporary increase amount of the engagement pressure in the engagement pressure increase control according to the pre-transmission shift torque.

5. The control device for a vehicle driving device according to claim 4 , wherein the electronic control unit increases the temporary increase amount of the engagement pressure in the engagement pressure increase control continuously or in a stepwise manner as the pre-transmission shift torque is reduced.

6. The control device for a vehicle driving device according to claim 1 , wherein the electronic control unit delays the start timing of the torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner as the transmission shift ratio of the transmission shift stage after the upshift control is reduced.

7. The control device for a vehicle driving device according to claim 1 , wherein, after starting the torque down control, the electronic control unit:

performs, as the torque down control, gradual torque down control for gradually reducing the torque of the driving force source,

ends the gradual torque down control after a rotation speed difference of the release side engagement device is generated,

performs rapid torque down control for reducing the torque of the driving force source at a speed higher than in the gradual torque down control, and

delays the start timing of the gradual torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner as the pre-transmission shift torque is reduced.

8. The control device for a vehicle driving device according to claim 2 , wherein the electronic control unit reduces a reduction speed of a torque of the driving force source in the torque down control continuously or in a stepwise manner as the pre-transmission shift torque is reduced.

9. The control device for a vehicle driving device according to claim 2 , wherein, after starting the inertia phase control, the electronic control unit performs engagement pressure increase control for temporarily increasing the engagement pressure of the engagement side engagement device and changes a temporary increase amount of the engagement pressure in the engagement pressure increase control according to the pre-transmission shift torque.

10. The control device for a vehicle driving device according to claim 3 , wherein, after starting the inertia phase control, the electronic control unit performs engagement pressure increase control for temporarily increasing the engagement pressure of the engagement side engagement device and changes a temporary increase amount of the engagement pressure in the engagement pressure increase control according to the pre-transmission shift torque.

11. The control device for a vehicle driving device according to claim 5 , wherein the electronic control unit:

delays the start timing of the torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner, and

increases the temporary increase amount of the engagement pressure in the engagement pressure increase control continuously or in a stepwise manner as one or both of the transmission shift ratio of the transmission shift stage before the upshift control and the transmission shift ratio of the transmission shift stage after the upshift control are reduced.

12. The control device for a vehicle driving device according to claim 2 , wherein the electronic control unit delays the start timing of the torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner as the transmission shift ratio of the transmission shift stage after the upshift control is reduced.

13. The control device for a vehicle driving device according to claim 2 , wherein, after starting the torque down control, the electronic control unit:

performs, as the torque down control, gradual torque down control for gradually reducing the torque of the driving force source,

ends the gradual torque down control after a rotation speed difference of the release side engagement device is generated,

performs rapid torque down control for reducing the torque of the driving force source at a speed higher than in the gradual torque down control, and

delays the start timing of the gradual torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner as the pre-transmission shift torque is reduced.

14. The control device for a vehicle driving device according to claim 8 , wherein, after starting the inertia phase control, the electronic control unit performs engagement pressure increase control for temporarily increasing the engagement pressure of the engagement side engagement device and changes a temporary increase amount of the engagement pressure in the engagement pressure increase control according to the pre-transmission shift torque.

15. The control device for a vehicle driving device according to claim 4 , wherein the electronic control unit:

delays the start timing of the torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner, and

increases the temporary increase amount of the engagement pressure in the engagement pressure increase control continuously or in a stepwise manner as one or both of the transmission shift ratio of the transmission shift stage before the upshift control and the transmission shift ratio of the transmission shift stage after the upshift control are reduced.

16. The control device for a vehicle driving device according to claim 3 , wherein the electronic control unit delays the start timing of the torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner as the transmission shift ratio of the transmission shift stage after the upshift control is reduced.

17. The control device for a vehicle driving device according to claim 3 , wherein, after starting the torque down control, the electronic control unit:

performs, as the torque down control, gradual torque down control for gradually reducing the torque of the driving force source,

ends the gradual torque down control after a rotation speed difference of the release side engagement device is generated,

performs rapid torque down control for reducing the torque of the driving force source at a speed higher than in the gradual torque down control, and

delays the start timing of the gradual torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner as the pre-transmission shift torque is reduced.

18. The control device for a vehicle driving device according to claim 14 , wherein the electronic control unit increases the temporary increase amount of the engagement pressure in the engagement pressure increase control continuously or in a stepwise manner as the pre-transmission shift torque is reduced.

19. The control device for a vehicle driving device according to claim 4 , wherein the electronic control unit delays the start timing of the torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner as the transmission shift ratio of the transmission shift stage after the upshift control is reduced.

20. The control device for a vehicle driving device according to claim 4 , wherein, after starting the torque down control, the electronic control unit:

performs, as the torque down control, gradual torque down control for gradually reducing the torque of the driving force source,

ends the gradual torque down control after a rotation speed difference of the release side engagement device is generated,

performs rapid torque down control for reducing the torque of the driving force source at a speed higher than in the gradual torque down control, and

delays the start timing of the gradual torque down control relative to the execution timing of the torque phase control continuously or in a stepwise manner as the pre-transmission shift torque is reduced.