Shift control apparatus and method for continuously variable transmission

• US 8,055,414 B2
• Filed: 07/04/2007
• Issued: 11/08/2011
• Est. Priority Date: 07/11/2006
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Tawara, Masahiro
• Primary Examiner(s): Beaulieu; Yonel
• Application Number:
  US12/307,833
• Publication Number:
  US 20090240405A1
• Time in Patent Office: 1,588 Days
• Field of Search: 701 52- 53, 701/62, 701/64, 701/93, 477 34- 37, 475 27-208
• US Class Current: 701/52
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/107 with endless flexible members
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: F16H 2061/6616 the shifting of the transmission being manually controlled
• CPC Class Codes: F16H 61/66259 using electrical or electronical sensing or control means
• CPC Class Codes: F16H 61/66272 characterised by means for controlling the torque transmitting capability of the gearing

Abstract

An ECT-ECU executes a program that includes a step of executing a stepped shift control if cruise control is not being executed during sequential shift control (stepped shift control) and a step of executing stepless shift control in response to cruise control being activated during sequential shift control (stepped shift control).

Claims

1. A shift control apparatus for a continuously variable transmission, comprising:

a shift mode switching device that selectively switches the shift mode of the continuously variable transmission between a stepless shift mode and a stepped shift mode in which the continuously variable transmission shifts non-continuously using a plurality of speed steps that are provided as predetermined speed ratios of the continuously variable transmission;

a command device that issues commands for upshift and downshift of the continuous variable transmission during the stepped shift mode;

a shift control device that, in response to the commands from the command device, controls the continuously variable transmission to shift from the present speed step to the next speed step during the stepped shift control; and

a determination device that determines whether a request for a cruise control is being made, wherein

the shift mode switching device includes a device that switches the shift mode of the continuously variable transmission from the stepped shift mode to the stepless shift mode in response to a request for the cruise control being made during the stepped shift mode.

2. The shift control apparatus according to claim 1, wherein

the shift mode switching device includes a device that switches the shift mode of the continuously variable transmission from the stepped shift mode to the stepless shift mode in response to a request for the cruise control being made during the stepped shift mode, and that switches the shift mode of the continuously variable transmission from the stepless shift mode back to the stepped shift mode in response to the request for the cruise control being cancelled.

3. The shift control apparatus according to claim 1, wherein

the command device includes a device that issues commands for upshift and downshift of the continuously variable transmission based on a predetermined condition, regardless of shift operations by a driver.

4. The shift control apparatus according to claim 1, wherein

the command device includes a device that issues commands for upshift and downshift of the continuously variable transmission based on manual operations by a driver.

8. The shift control apparatus according to claim 2, wherein

the command device includes a device that issues commands for upshift and downshift of the continuously variable transmission based on a predetermined condition, regardless of shift operations by a driver.

9. The shift control apparatus according to claim 2, wherein

the command device includes a device that issues commands for upshift and downshift of the continuously variable transmission based on manual operations by a driver.

5. A shift control apparatus for a continuously variable transmission, comprising:

a shift mode switching device that selectively switches the shift mode of the continuously variable transmission between a stepless shift mode and a stepped shift mode in which the continuously variable transmission shifts non-continuously using a plurality of speed steps that are provided as predetermined speed ratios of the continuously variable transmission;

a command device that issues commands for upshift and downshift of the continuous variable transmission during the stepped shift mode;

a shift control device that, in response to the commands from the command device, controls the continuously variable transmission to shift from the present speed step to the next speed step during the stepped shift control; and

a determination device that determines whether a request for a cruise control is being made, wherein

the shift mode switching device includes a device that, in response to a request for a cruise control being made, changes the speed ratios of the speed steps so as to be closer to each other according to a target vehicle speed of the cruise control.

6. A shift control method for a continuously variable transmission, comprising:

selectively switching the shift mode of the continuously variable transmission between a stepless shift mode and a stepped shift mode in which the continuously variable transmission shifts non-continuously using a plurality of speed steps that are provided as predetermined speed ratios of the continuously variable transmission;

issuing commands for upshift and downshift of the continuous variable transmission during the stepped shift mode;

controlling, in response to the commands, the continuously variable transmission to shift from the present speed step to the next speed step during the stepped shift control;

determining whether a request for a cruise control is being made; and

switching the shift mode of the continuously variable transmission from the stepped shift mode to the stepless shift mode in response to a request for the cruise control being made during the stepped shift mode.

7. A shift control method for a continuously variable transmission, comprising:

selectively switching the shift mode of the continuously variable transmission between a stepless shift mode and a stepped shift mode in which the continuously variable transmission shifts non-continuously using a plurality of speed steps that are provided as predetermined speed ratios of the continuously variable transmission;

issuing commands for upshift and downshift of the continuous variable transmission during the stepped shift mode;

controlling, in response to the commands, the continuously variable transmission to shift from the present speed step to the next speed step during the stepped shift control;

determining whether a request for a cruise control is being made; and

changing, in response to a request for a cruise control being made, the speed ratios of the speed steps so as to be closer to each other according to a target vehicle speed of the cruise control.