Continuously variable transmission controller

• US 20070004552A1
• Filed: 06/29/2006
• Published: 01/04/2007
• Est. Priority Date: 06/30/2005
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Asumi, Michio, Matsudaira, Naotada
• Granted Patent: US 7,559,872 B2
• Time in Patent Office: Days
• US Class Current: 477/37
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/107 with endless flexible members
• CPC Class Codes: B60W 30/182 Selecting between different operative modes, e.g. comfort and performance modes
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: F16H 2300/14 Selecting a state of operation, e.g. depending on two wheel or four wheel drive mode
• CPC Class Codes: F16H 61/66254 controlling of shifting being influenced by a signal derived from the engine and the main coupling

Abstract

A continuously variable transmission is mounted on a vehicle capable of selecting plural drive modes and changes a target engine speed between drive modes. A pulley ratio is controlled by a motor. An ECU for transmission control includes a calculation section which outputs a target engine speed as a function of throttle opening and vehicle speed, and a motor control value determination section which outputs a control value for controlling the motor based on the target engine speed and an actual engine speed. In a case where, when a drive mode is selected, the current target engine speed changes by an amount exceeding a predetermined judgment value according to vehicle speed, the motor control value determination section updates the current target engine speed in a stepwise manner. The resulting configuration reduces a shift shock caused by a drive mode change.

Claims

1. A controller for a continuously variable transmission capable of selecting plural drive modes, comprising:

means for detecting a throttle opening;

means for detecting a vehicle speed;

means for detecting an engine speed;

an actuator for changing a transmission gear ratio of the continuously variable transmission;

target value output means for outputting a target engine speed as a function of the throttle opening and the vehicle speed; and

shift characteristic determination means for determining a driving direction and a driving speed of the actuator based on a difference between the target engine speed and an actual engine speed,

wherein the shift characteristic determination means includes shift characteristic changing means for updating a current target engine speed on a stepwise basis to change to a value for use after a change in a drive mode, in a case where it is judged that the current target engine speed is changed by an amount exceeding a predetermined judgment value according to the vehicle speed when the drive mode is selected.

2. The continuously variable transmission controller according to claim 1, comprising:

means for deciding a throttle opening judgment value set as a function of the drive mode and the vehicle speed;

wherein the shift characteristic changing means is configured such that,

when a current throttle opening is larger than the throttle opening judgment value, the target engine speed is updated according to the drive mode, and

when a current throttle opening is smaller than the throttle opening judgment value, the target engine speed is updated according to the drive mode and the vehicle speed.

3. The continuously variable transmission controller according to claim 1, wherein:

an updating speed of the target engine speed differs depending on whether the drive mode change causes the target engine speed to increase or decrease.

4. The continuously variable transmission controller according to claim 1, wherein:

an updating speed of the target engine speed is made lower when the engine speed is higher according to engine speed when the drive mode is changed.

5. The continuously variable transmission controller according to claim 1, wherein the drive mode includes a sport drive mode and a fuel-efficient drive mode.

6. The continuously variable transmission controller according to claim 1, wherein the shift characteristic changing means is adapted to change the target engine speed gradually so as to extend a time used to change a pulley ratio when a difference between the target engine speed and the actual engine speed is larger than the predetermined judgment value corresponding to the vehicle speed.

7. The continuously variable transmission controller according to claim 1, wherein the predetermined judgment value is read out from a prepared map corresponding to the vehicle speed.

8. The continuously variable transmission controller according to claim 1, wherein the drive mode is selected by a mode switch connected to the controller.

9. The continuously variable transmission controller according to claim 1, wherein the actuator is a slider for changing a distance between a fixed piece and a movable piece of a drive pulley of the transmission.

10. The continuously variable transmission controller according to claim 1, wherein a variation per time unit of the target engine speed is determined by the drive mode and the vehicle speed, or by the drive mode only, depending on a magnitude of the throttle opening.

11. An electronic controller for a continuously variable transmission capable of selecting plural drive modes, comprising:

a throttle opening sensor;

a vehicle speed sensor;

an engine speed sensor;

an actuator for changing a transmission gear ratio of the continuously variable transmission;

a target value calculation section for outputting a target engine speed as a function of a throttle opening and a vehicle speed; and

a motor control value determination section for determining a driving direction and a driving speed of the actuator based on a difference between the target engine speed and an actual engine speed,

wherein the motor control value determination section includes shift characteristic changing means for updating a current target engine speed in a stepwise manner to change to a value for use after a change in a drive mode, in a case where it is judged that the current target engine speed is changed by an amount exceeding a predetermined judgment value according to the vehicle speed when the drive mode is selected.

12. The electronic controller for a continuously variable transmission according to claim 11, comprising:

means for deciding a throttle opening judgment value set as a function of the drive mode and the vehicle speed;

wherein the shift characteristic changing means is configured such that,

when a current throttle opening is larger than the throttle opening judgment value, the target engine speed is updated according to the drive mode, and

when a current throttle opening is smaller than the throttle opening judgment value, the target engine speed is updated according to the drive mode and the vehicle speed.

13. The electronic controller for a continuously variable transmission according to claim 11, wherein:

an updating speed of the target engine speed differs depending on whether the drive mode change causes the target engine speed to increase or decrease.

14. The electronic controller for a continuously variable transmission according to claim 11, wherein:

an updating speed of the target engine speed is made lower when the engine speed is higher according to engine speed when the drive mode is changed.

15. The electronic controller for a continuously variable transmission according to claim 11, wherein the drive mode includes a sport drive mode and a fuel-efficient drive mode.

16. The electronic controller for a continuously variable transmission according to claim 11, wherein the shift characteristic changing means is adapted to change the target engine speed gradually so as to extend a time used to change a pulley ratio when a difference between the target engine speed and the actual engine speed is larger than the predetermined judgment value corresponding to the vehicle speed.

17. The electronic controller for a continuously variable transmission according to claim 11, wherein the predetermined judgment value is read out from a prepared map corresponding to the vehicle speed.

18. The electronic controller for a continuously variable transmission according to claim 11, wherein the drive mode is selected by a mode switch connected to the controller.

19. The electronic controller for a continuously variable transmission according to claim 11, wherein the actuator is a slider for changing a distance between a fixed piece and a movable piece of a drive pulley of the transmission.

20. The electronic controller for a continuously variable transmission according to claim 11, wherein a variation per time unit of the target engine speed is determined by the drive mode and the vehicle speed, or by the drive mode only, depending on a magnitude of the throttle opening.