STOCHASTIC DETECTION OF TORQUE CONVERTER SLIP SPEED AND RELATED CONTROL

• US 20110166758A1
• Filed: 01/04/2010
• Published: 07/07/2011
• Est. Priority Date: 01/04/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Lee, Chunhao J., Otanez, Paul G., Samie, Farzad
• Granted Patent: US 8,447,508 B2
• Time in Patent Office: Days
• US Class Current: 701/67
• CPC Class Codes: F16H 2059/467 of torque converter
• CPC Class Codes: F16H 2061/145 for controlling slip, e.g. approaching target slip value
• CPC Class Codes: F16H 61/143 using electric control means

Abstract

A method for controlling torque converter slip includes operating the torque converter in a controlled slip mode, monitoring slip in the torque converter, statistically analyzing the monitored slip to determine a likely condition of the torque converter, and utilizing the likely condition of the torque converter to control the torque converter slip.

Claims

1. Method for controlling torque converter slip in a powertrain comprising an engine, a transmission, and a torque converter located between the engine and the transmission, the method comprising:

operating the torque converter in a controlled slip mode;

monitoring slip in the torque converter;

statistically analyzing the monitored slip to determine a likely condition of the torque converter; and

utilizing the likely condition of the torque converter to control the torque converter slip.

2. The method of claim 1, wherein statistically analyzing the monitored slip to determine the likely condition of the torque converter comprises determining a locked condition of a torque converter clutch of the torque converter.

3. The method of claim 2, wherein determining the locked condition of torque converter clutch of the torque converter comprises determining a first probability that the slip in the torque converter is zero.

4. The method of claim 3, wherein determining the locked condition of torque converter clutch of the torque converter further comprises:

determining a second probability that the slip in the torque converter is not zero;

comparing the first and second probabilities; and

wherein determining the locked condition of torque converter clutch is based upon comparing the first and second probabilities.

5. The method of claim 1, wherein statistically analyzing the monitored slip to determine the likely condition of the torque converter comprises determining a low slip condition of a torque converter clutch of the torque converter.

6. The method of claim 5, wherein determining the low slip condition of the torque converter clutch of the torque converter comprises determining a first probability that the slip in the torque converter is less than a non-zero low slip threshold speed.

7. The method of claim 6, wherein the determining the low slip condition of the torque converter clutch of the torque converter further comprises:

determining a second probability that the slip in the torque converter is a non-zero value describing the torque converter to be not locked;

comparing the first and second probabilities; and

determining the low slip condition of the torque converter clutch based upon comparing the first and second probabilities.

8. The method of claim 1, wherein the utilizing the likely condition of the torque converter to control the torque converter slip comprises commanding a drop to a command pressure of a torque converter clutch of the torque converter.

9. The method of claim 1, wherein statistically analyzing the monitored slip to determine the likely condition of the torque converter comprises determining a high slip condition of a torque converter clutch of the torque converter.

10. The method of claim 1, wherein statistically analyzing the monitored slip to determine the likely condition of the torque converter comprises determining a high slip condition of a torque converter clutch of the torque converter;

and

wherein utilizing the likely condition of the torque converter to control the torque converter slip comprises commanding an increase to a command pressure of a torque converter clutch of the torque converter based upon the high slip condition.

11. The method of claim 10, wherein the utilizing statistical analysis of the monitored slip to determine the likely condition of the torque converter further comprises determining a low slip condition of the torque converter clutch of the torque converter;

and

wherein the utilizing the determined likely condition of the torque converter to control the torque converter slip further comprises commanding a drop to a command pressure of the torque converter clutch of the torque converter based upon the low slip condition.

12. Method for controlling torque converter slip in a powertrain comprising an engine, a transmission, and a torque converter located between the engine and the transmission, the method comprising:

operating the torque converter in a controlled slip mode;

monitoring slip in the torque converter;

statistically analyzing the monitored slip to determine an occurrence of a crashed condition in the torque converter; and

utilizing the occurrence of the crashed condition to control the torque converter slip.

13. The method of claim 12, wherein determining occurrence of the crashed condition in the torque converter comprises:

determining a first probability that the torque converter is in the crashed condition;

determining a second probability that the torque converter is not in the crashed condition;

determining a ratio of the first and second probabilities; and

determining the occurrence of the crashed condition based upon the ratio.

14. The method of claim 13, wherein determining the occurrence of the crashed condition based upon the ratio comprises determining the occurrence using iterative values of the ratio.

15. The method of claim 14, wherein determining the using iterative values of the ratio comprises:

calculating respective logarithms of the iterative values of the ratio;

summing the logarithms of the iterative values through a summing sample period; and

determining the occurrence of the crashed condition based upon the summing.

16. The method of claim 15, wherein determining the occurrence of the crashed condition based upon the summing comprises:

plotting iterative results of the summing; and

determining the occurrence of the crashed condition based upon the plotting.

17. The method of claim 16, wherein the plotting iterative results of the summing comprises:

comparing iterative results of the summing to determine an inflection in the iterative results; and

initiating the plotting of iterative results of the summing based upon the comparing determining an inflection indicating a possible crashed condition; and

determining the occurrence of the crashed condition based upon the iterative results of the summing exceeding an indication threshold describing the crashed condition.

18. The method of claim 16, wherein determining the occurrence of the crashed condition based upon the plotting comprises:

determining a rate of change of the iterative results of the summing; and

determining the occurrence of the crashed condition based upon the rate of change indicating a likely crashed condition through a minimum time period.

19. The method of claim 12, wherein determining the occurrence of the crashed condition in the torque converter comprises:

determining a probability that the torque converter is in the crashed condition;

comparing the probability that the torque converter is in the crashed condition to a threshold probability; and

determining the occurrence of the crashed condition based upon the comparing.