System and Method of Operating a Machine Having a Continuously Variable Transmission

• US 20140121919A1
• Filed: 11/01/2012
• Published: 05/01/2014
• Est. Priority Date: 11/01/2012
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Nackers, Adam, Davis, Kevin
• Granted Patent: US 9,169,926 B2
• Time in Patent Office: Days
• US Class Current: 701/55
• CPC Class Codes: F16H 47/04 the mechanical gearing being of the type with members having orbital motion
• CPC Class Codes: F16H 61/462 for achieving a target speed ratio

Abstract

A system and method involves a machine that powertrain including a continuously variable transmission (CVT) and a machine speed sensor to determine a measured machine speed. The machine also includes a controller in communication with the CVT and the speed sensor. The controller may include a table relating the measured machine speed to a plurality of virtual gear ratios associated with the CVT. The controller is configured to determine a calculated virtual gear ratio using the table and, if desired, may display the calculated virtual gear ratio on a visual display.

Claims

1. A machine comprising:

a continuously variable transmission (CVT);

a machine speed sensor for determining a measured machine speed;

a controller in communication with the CVT and the machine speed sensor, the controller including a table relating the measured machine speed to a plurality of virtual gear ratios associated with the CVT, the controller further configured to determine a calculated virtual gear ratio using the table.

2. The machine of claim 1, further comprising a visual display in communication with the controller for displaying the calculated virtual gear ratio.

3. The machine of claim 2, further comprising a virtual gear shifter enabling operator selection of a selected virtual gear ratio from the plurality of virtual gear ratios.

4. The machine of claim 3, wherein the visual display further displays the selected virtual gear ratio in comparison with the calculated virtual gear ratio.

5. The machine of claim 4, wherein the visual display is further configured to display the measured machine speed.

6. The machine of claim 1, wherein each virtual gear ratio of the plurality of virtual gear ratios has an associated minimum virtual gear speed and an associated maximum virtual gear speed.

7. The machine of claim 6, wherein the table includes at least the maximum virtual gear speed for each virtual gear ratio;

and the controller determines the calculated virtual gear ratio by comparing the measured machine speed with the maximum virtual gear speeds.

8. The machine of claim 6, wherein the table includes speed ranges between the minimum virtual gear speed and the maximum virtual gear speed for each virtual gear ratio, and the controller determines the calculated virtual gear ratio by selecting the lowest possible virtual gear ratio having a speed range including the measured machine speed.

9. The machine of claim 1, wherein the CVT is operatively coupled to a power source.

10. A method of operating a machine having a power source operatively coupled to a continuously variable transmission (CVT), the method comprising:

selecting a selected virtual gear ratio from a plurality of virtual gear ratios associated with the CVT;

operating the machine in accordance with the selected virtual gear ratio;

measuring a measured machine speed; and

comparing the measured machine speed to a table to determine a calculated virtual gear ratio.

11. The method of claim 10, wherein each virtual gear ratio of the plurality of virtual gear ratios has an associated minimum virtual gear speed and an associated maximum virtual gear speed.

12. The method of claim 11, wherein the table includes at least the maximum virtual gear speed for each virtual gear ratio;

and the step of comparing compares the measured machine speed with the maximum virtual gear speeds to determine the calculated virtual gear ratio.

13. The method of claim 11, wherein the table includes speed ranges between the minimum virtual gear speed and the maximum virtual gear speed for each virtual gear ratio, and step of comparing selects the lowest possible virtual gear ratio having a speed range including the measured machine speed.

14. The method of claim 11, further comprising displaying the calculated virtual gear ratio on a visual display.

15. The method of claim 14, further comprising displaying the selected virtual gear ratio on the visual display.

16. The method of claim 15, wherein the calculated virtual gear ratio will be less than the selected virtual gear ratio if the measured machine speed is less than the maximum virtual gear speed for the selected virtual gear ratio.

17. The method of claim 10, wherein a machine speed sensor is operatively associated with a propulsion device of the machine for measuring the measured machine speed.

18. A controller for controlling a machine including a continuously variable transmission (CVT), the controller comprising:

a communication link to a machine speed sensor measuring a measured machine speed;

data for a plurality of virtual gear ratios, each virtual gear ratio having an associated minimum virtual gear speed and an associated maximum virtual gear speed;

a reverse lookup table correlating the measured machine speed to a calculated virtual gear ratio by referencing the maximum virtual gear speed.

19. The controller of claim 18, wherein the controller further instructs a visual display to display the calculated virtual gear ratio.

20. The controller of claim 18, wherein the controller enables selection of a selected virtual gear ratio and operates the machine in accordance with the selected virtual gear ratio.