METHOD FOR SYNCHRONIZED TRANSMISSION GEAR RATIO ENGAGEMENT

• US 20100274453A1
• Filed: 04/22/2009
• Published: 10/28/2010
• Est. Priority Date: 04/22/2009
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Mitts, Kurt, Dlugoss, Randall B.
• Granted Patent: US 8,150,586 B2
• Time in Patent Office: Days
• US Class Current: 701/51
• CPC Class Codes: F16H 59/46 dependent on a comparison between speeds
• CPC Class Codes: F16H 61/0403 Synchronisation before shifting
• CPC Class Codes: F16H 61/2807 using electric control signals for shift actuators, e.g. electro-hydraulic control therefor F16H61/30, F16H61/32 take precedence; methods for generating shift signals F16H61/0213
• CPC Class Codes: F16H 61/688 with two inputs, e.g. selection of one of two torque-flow paths by clutches
• CPC Class Codes: Y10T 74/19284 Meshing assisters

Abstract

A method is provided for changing a gear ratio in a transmission of a motor vehicle. Engagement of a first gear-train component with a second gear-train component is initiated at a predetermined rate. Rotational speeds of the first and the second gear-train components, and whether the rotational speed of the first gear-train component and the rotational speed of the second gear-train component have substantially synchronized is determined. A rate of engagement of the two gear-train components is reduced, if the rotational speed of the first gear-train component has not substantially synchronized with rotational speed of the second gear-train component. The rate of engagement of the two gear-train components is increased, if the rotational speed of the first gear-train component has substantially synchronized with rotational speed of the second gear-train component. Following the conclusion of engagement between the two gear-train components, the gear ratio change is completed.

Claims

1. A method for changing a gear ratio in a transmission of a motor vehicle, comprising:

commencing the gear ratio change by initiating engagement of a first gear-train component with a second gear-train component at a predetermined rate;

determining rotational speed of the first gear-train component;

determining rotational speed of the second gear-train component;

determining whether the rotational speed of the first gear-train component and the rotational speed of the second gear-train component have substantially synchronized;

reducing the rate of engagement of the first gear-train component with the second gear-train component if the rotational speed of the first gear-train component has not substantially synchronized with rotational speed of the second gear-train component;

increasing the rate of engagement of the first gear-train component with the second gear-train component if the rotational speed of the first gear-train component has substantially synchronized with rotational speed of the second gear-train component; and

completing the gear ratio change.

2. The method of claim 1, wherein said determining of the rotational speed of the first gear-train component is accomplished by a first speed sensor, and the determining of the rotational speed of the second gear-train component is accomplished by a second speed sensor.

3. The method of claim 1, wherein said initiating engagement of the first gear-train component with the second gear-train component at a predetermined rate, said determining rotational speed of the first gear-train component, said determining rotational speed of the second gear-train component, said determining whether the rotational speed of the first gear-train component and the rotational speed of the second gear-train component have substantially synchronized, said reducing the rate of engagement of the first gear-train component with the second gear-train component, said increasing the rate of engagement of the first gear-train component with the second gear-train component;

and said completing the gear ratio change are directed by a controller.

4. The method of claim 1, wherein the rotational speed of the first gear-train component and the rotational speed of the second gear-train component have substantially synchronized when the rotational speed of first gear-train component and the rotational speed of the second gear-train component are within a predetermined maximum difference.

5. The method of claim 1, wherein the engagement of the first gear-train component with the second gear-train component is accomplished via a force applied by an actuator.

6. The method of claim 5, wherein said reducing the rate of engagement of the first gear-train component with the second gear-train component is accomplished by reducing the force applied by the actuator, and said increasing the rate of engagement of the first gear-train component with the second gear-train component is accomplished by increasing the force applied by the actuator.

7. The method of claim 7, wherein the actuator is a hydraulic pressure device configured to displace one of the first and the second gear-train components.

8. The method of claim 7, wherein the actuator is a solenoid configured to displace one of the first and the second gear-train components.

9. The method of claim 7, wherein the actuator is an electric motor configured to displace one of the first and the second gear-train components.

10. A method for controlling a multi-speed dual-clutch transmission comprising:

holding a first clutch engaged, wherein a first transmission input member is coupled to a transmission output member while a second clutch engageable to couple a second transmission input member to the output member remains disengaged;

commencing the gear ratio change by initiating engagement of a first gear-train component with a second gear-train component at a predetermined rate;

determining rotational speed of the first gear-train component;

determining rotational speed of the second gear-train component;

determining whether the rotational speed of the first gear-train component and the rotational speed of the second gear-train component have substantially synchronized;

reducing the rate of engagement of the first gear-train component with the second gear-train component if the rotational speed of the first gear-train component has not substantially synchronized with rotational speed of the second gear-train component;

increasing the rate of engagement of the first gear-train component with the second gear-train component if the rotational speed of the first gear-train component has substantially synchronized with rotational speed of the second gear-train component to conclude engagement of the first gear-train component with the second gear-train component; and

disengaging the first clutch and engaging the second clutch, whereby the second transmission input member is coupled to the output member.

11. The method of claim 10, wherein said determining of the rotational speed of the first gear-train component is accomplished by a first speed sensor, and said determining of the rotational speed of the second gear-train component is accomplished by a second speed sensor.

12. The method of claim 10, wherein said commencing the gear ratio change, said determining rotational speed of the first gear-train component, said determining rotational speed of the second gear-train component, said determining whether the rotational speed of the first gear-train component and the rotational speed of the second gear-train component have substantially synchronized, said reducing the rate of engagement of the first gear-train component with the second gear-train component, said increasing the rate of engagement of the first gear-train component with the second gear-train component, and said disengaging the first clutch and engaging the second clutch are directed by a controller.

13. The method of claim 10, wherein the rotational speed of the first gear-train component and the rotational speed of the second gear-train component have substantially synchronized when the rotational speed of first gear-train component and the rotational speed of the second gear-train component are within a predetermined maximum difference.

14. The method of claim 10, wherein the engagement of the first gear-train component with the second gear-train component is accomplished via a force applied by an actuator.

15. The method of claim 14, wherein said reducing the rate of engagement of the first gear-train component with the second gear-train component is accomplished by reducing the force applied by the actuator, and said increasing the rate of engagement of the first gear-train component with the second gear-train component is accomplished by increasing the force applied by the actuator.

16. The method of claim 14, wherein the actuator is a hydraulic pressure device configured to displace one of the first and the second gear-train components.

17. The method of claim 14, wherein the actuator is a solenoid configured to displace one of the first and the second gear-train components.

18. The method of claim 14, wherein the actuator is an electric motor configured to displace one of the first and the second gear-train components.

19. A method for changing a gear ratio in a transmission having a first gear-train component and a second gear-train component, comprising:

reducing the rate of engagement of the first gear-train component with the second gear-train component if the rotational speed of the first gear-train component has not substantially synchronized with rotational speed of the second gear-train component;

increasing the rate of engagement of the first gear-train component with the second gear-train component if the rotational speed of the first gear-train component has substantially synchronized with rotational speed of the second gear-train component; and

completing the gear ratio change.