Method and system for controlling rate of change of ratio in a continuously variable transmission

• US 20040254047A1
• Filed: 03/19/2004
• Published: 12/16/2004
• Est. Priority Date: 03/19/2003
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Dreumont, Thomas, Frank, Andrew A.
• Granted Patent: US 7,261,672 B2
• Time in Patent Office: Days
• US Class Current: 477/37
• CPC Class Codes: B60K 6/36 characterised by the transmission gearings
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 2260/14 of transmissions
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/101 Infinitely variable gearings
• CPC Class Codes: B60W 10/107 with endless flexible members
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/11 using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance utilising navigation and traffic information in the control strategy B60W20/12
• CPC Class Codes: B60W 20/30 Control strategies involving selection of transmission gear ratio control of change speed gearings, together with other vehicle sub-units B60W10/10; HEV transmission gearing B60K6/36; gearings and control thereof F16H
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2710/0672 Torque change rate
• CPC Class Codes: B60W 2710/1055 Output torque change rate
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: F16H 2059/702 Rate of change of gear ratio, e.g. for triggering clutch engagement
• CPC Class Codes: F16H 2061/66277 by optimising the clamping force exerted on the endless flexible member
• CPC Class Codes: F16H 61/66254 : controlling of shifting being influenced by a signal derived from the engine and the main coupling
• CPC Class Codes: F16H 61/66272 : characterised by means for controlling the torque transmitting capability of the gearing
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles

Abstract

Systems and methods for efficiently and effectively controlling the rate of change of ratio, not simply the ratio, in a CVT. By controlling the rate of change of ratio, the acceleration or deceleration of a vehicle can be controlled in an efficient manner. Furthermore, the rate of change of ratio can be controlled by controlling the clamping pressure of the pulleys and/or differential pressure between the pulleys with minimal slip by using a servo control mechanism adapted for control by a system controller based on equilibrium mapping and other control parameters.

Claims

1. An apparatus for controlling the operation of a continuously variable transmission (CVT), comprising:

a programmable controller; and

means associated with said controller for mapping rate of change of ratio to clamping pressure and/or differential pressure between pulleys in said CVT.

2. An apparatus as recited in claim 1, further comprising a hydraulic servo control system adapted for control by said programmable controller and for control of clamping pressure and differential pressure between pulleys in said CVT.

3. An apparatus for controlling the rate of change ratio in a continuously variable transmission (CVT), comprising:

a programmable controller;

programming associated with said controller for mapping rate of change of ratio to clamping pressure and/or differential pressure between pulleys in said CVT.

4. An apparatus as recited in claim 3, further comprising a hydraulic servo control system adapted for control by said programmable controller and for control of clamping pressure and differential pressure between pulleys in said CVT.

5. An apparatus for controlling the operation of a continuously variable transmission (CVT), comprising:

a programmable controller;

an algorithm or map associated with said controller, wherein said algorithm or map determines clamping pressure and/or differential pressure level between pulleys in said CVT for achieving a desired rate of change in ratio in said CVT.

6. An apparatus as recited in claim 5, further comprising a hydraulic servo control system adapted for control by said programmable controller and for control of clamping pressure and/or differential pressure between pulleys in said CVT.

7. An apparatus for optimizing the operation of a continuously variable transmission (CVT), comprising:

a control computer; and

programming associated with said control computer for carrying out the operations of controlling primary and secondary pulley pressure of a CVT to achieve a commanded clamping pressure in response to an input torque command and commanded ratio rate or shift velocity based on a mapping of empirical data relating pressure, ratio rate, and torque.

8. An apparatus as recited in claim 7, further comprising a hydraulic servo control system adapted for control of said primary and second pulley pressure in response to said control computer.

9. An apparatus for optimizing the operation of a continuously variable transmission (CVT), comprising:

(a) a control computer; and

(b) programming associated with said control computer for

(i) accessing a map of the relationship between pressure of a CVT and rate of change of ratio to transmit a given amount of torque, and

(ii) controlling primary and second pulley pressure of the CVT to achieve a commanded clamping pressure for commanded torque and ratio rate based on said map.

10. An apparatus as recited in claim 9, further comprising a hydraulic servo control system adapted for control of said primary and second pulley pressure in response to said control computer.

11. An apparatus for optimizing the operation of a continuously variable transmission (CVT), comprising:

(a) a control computer; and

(b) programming associated with said control computer for carrying out the operations of controlling primary and secondary pulley pressures of the CVT to control the ratio rate and/or ratio and clamping pressure of the CVT based on an equilibrium ratio map of the CVT and the pressure relationship between the ratio rate of the CVT and the distance between the point corresponding to the current states of the CVT and the projection of this point onto said equilibrium ratio map.

12. An apparatus as recited in claim 11, further comprising a hydraulic servo control system adapted for control of said primary and second pulley pressure in response to said control computer.

25. A hybrid electric vehicle as recited in claim 11, further comprising a hydraulic servo control system adapted for control of said primary and second pulley pressure in response to said system controller.

13. An apparatus for controlling the operating of a continuously variable transmission (CVT) comprising:

a servo control system;

said servo control system configured to control clamping pressure and differential pressure between primary and secondary pulleys in the CVT;

a control computer; and

programming associated with said control computer for controlling said servo control system to achieve commanded clamping pressure and/or differential pressure between the primary and secondary pulleys based on a mapping of rate of change of ratio of said CVT to said clamping pressure and/or differential pressure between pulleys.

14. A hybrid electric vehicle, comprising:

a continuously variable transmission (CVT);

an internal combustion engine coupled to the CVT;

an electric motor coupled to the output of the internal combustion engine;

a system controller configured to operate said motor simultaneously with said engine and apply motor torque to said engine output to maintain engine power or torque output substantially along a predetermined operating line;

said system controller further configured to control rate of change of ratio of said continuously variable transmission;

wherein said system controller varies acceleration and deceleration of said vehicle by varying motor torque and rate of change of ratio of said continuously variable transmission; and

means associated with said controller for mapping rate of change of ratio to clamping pressure and/or differential pressure between pulleys in said CVT.

15. A hybrid electric vehicle as recited in claim 14, further comprising a hydraulic servo control system adapted for control by said system controller and for control of clamping pressure and differential pressure between pulleys in said CVT.

16. A hybrid electric vehicle, comprising:

a continuously variable transmission (CVT);

an internal combustion engine coupled to the CVT;

an electric motor coupled to the output of the internal combustion engine;

a system controller configured to operate said motor simultaneously with said engine and apply motor torque to said engine output to maintain engine power or torque output substantially along a predetermined operating line;

said system controller further configured to control rate of change of ratio of said continuously variable transmission;

wherein said system controller varies acceleration and deceleration of said vehicle by varying motor torque and rate of change of ratio of said continuously variable transmission; and

programming associated with said system controller for mapping rate of change of ratio to clamping pressure and/or differential pressure between pulleys in said CVT.

17. A hybrid electric vehicle as recited in claim 16, further comprising a hydraulic servo control system adapted for control by said system controller and for control of clamping pressure and differential pressure between pulleys in said CVT.

18. A hybrid electric vehicle, comprising:

a continuously variable transmission (CVT);

an internal combustion engine coupled to the CVT;

an electric motor coupled to the output of the internal combustion engine;

a system controller configured to operate said motor simultaneously with said engine and apply motor torque to said engine output to maintain engine power or torque output substantially along a predetermined operating line;

said system controller further configured to control rate of change of ratio of said continuously variable transmission;

wherein said system controller varies acceleration and deceleration of said vehicle by varying motor torque and rate of change of ratio of said continuously variable transmission; and

an algorithm or map associated with said system controller, wherein said algorithm or map determines clamping pressure and/or differential pressure level between pulleys in said CVT for achieving a desired rate of change in ratio in said CVT.

19. A hybrid electric vehicle as recited in claim 18, further comprising a hydraulic servo control system adapted for control by said programmable controller and for control of clamping pressure and differential pressure between pulleys in said CVT.

20. A hybrid electric vehicle, comprising:

a continuously variable transmission (CVT);

an internal combustion engine coupled to the CVT;

an electric motor coupled to the output of the internal combustion engine;

a system controller configured to operate said motor simultaneously with said engine and apply motor torque to said engine output to maintain engine power or torque output substantially along a predetermined operating line;

said system controller further configured to control rate of change of ratio of said continuously variable transmission;

wherein said system controller varies acceleration and deceleration of said vehicle by varying motor torque and rate of change of ratio of said continuously variable transmission; and

programming associated with said system controller for carrying out the operations of controlling primary and secondary pulley pressure of a CVT to achieve a commanded clamping pressure in response to an input torque command and commanded ratio rate or shift velocity based on a mapping of empirical data relating pressure, ratio rate, and torque.

21. A hybrid electric vehicle as recited in claim 20, further comprising a hydraulic servo control system adapted for control of said primary and second pulley pressure in response to said system controller.

22. A hybrid electric vehicle, comprising:

a continuously variable transmission (CVT);

an internal combustion engine coupled to the CVT;

an electric motor coupled to the output of the internal combustion engine;

a system controller configured to operate said motor simultaneously with said engine and apply motor torque to said engine output to maintain engine power or torque output substantially along a predetermined operating line;

said system controller further configured to control rate of change of ratio of said continuously variable transmission;

wherein said system controller varies acceleration and deceleration of said vehicle by varying motor torque and rate of change of ratio of said continuously variable transmission; and

programming associated with said system controller computer for

(i) accessing a map of the relationship between pressure of a CVT and rate of change of ratio to transmit a given amount of torque, and

(ii) controlling primary and second pulley pressure of the CVT to achieve a commanded clamping pressure for commanded torque and ratio rate based on said map.

23. A hybrid electric vehicle as recited in claim 22, further comprising a hydraulic servo control system adapted for control of said primary and second pulley pressure in response to said system controller.

24. A hybrid electric vehicle, comprising:

a continuously variable transmission (CVT);

an internal combustion engine coupled to the CVT;

an electric motor coupled to the output of the internal combustion engine;

a system controller configured to operate said motor simultaneously with said engine and apply motor torque to said engine output to maintain engine power or torque output substantially along a predetermined operating line;

said system controller further configured to control rate of change of ratio of said continuously variable transmission;

wherein said system controller varies acceleration and deceleration of said vehicle by varying motor torque and rate of change of ratio of said continuously variable transmission; and

programming associated with said system controller for carrying out the operations of controlling primary and secondary pulley pressures of the CVT to control the ratio rate and/or ratio and clamping pressure of the CVT based on an equilibrium ratio map of the CVT and the pressure relationship between the ratio rate of the CVT and the distance between the point corresponding to the current states of the CVT and the projection of this point onto said equilibrium ratio map.

26. A hybrid electric vehicle, comprising:

a continuously variable transmission (CVT);

an internal combustion engine coupled to the CVT;

an electric motor coupled to the output of the internal combustion engine;

a system controller configured to operate said motor simultaneously with said engine and apply motor torque to said engine output to maintain engine power or torque output substantially along a predetermined operating line;

said system controller further configured to control rate of change of ratio of said continuously variable transmission;

wherein said system controller varies acceleration and deceleration of said vehicle by varying motor torque and rate of change of ratio of said continuously variable transmission;

a servo control system;

said servo control system configured to control clamping pressure and differential pressure between primary and secondary pulleys in the CVT; and

programming associated with said system controller for controlling said servo control system to achieve commanded clamping pressure and/or differential pressure between the primary and secondary pulleys based on a mapping of rate of change of ratio of said CVT to said clamping pressure and/or differential pressure between pulleys.

27-32. -32. (canceled)