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1. WO2013012483 - SYSTEM AND METHOD FOR MANAGING AN OPERATING TEMPERATURE OF A WORKING FLUID IN A VEHICLE POWERTRAIN

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

WHAT IS CLAIMED IS:

1. A system for managing a temperature of a working fluid in a vehicle powertrain, the vehicle powertrain including a power source configured to output torque and a transmission including the working fluid, the transmission selectively coupled to the power source and configured to multiply and output the torque from the power source, the system comprising: a temperature sensor in thermal contact with the working fluid and configured to output data indicative of a real-time temperature of the working fluid; and

a controller in electrical communication with the temperature sensor and at least one of the power source and the transmission, the controller configured to,

compare the data from the temperature sensor to a temperature threshold, select a terminal speed limit when the data indicates that real-time temperature is less than or substantially equal to the temperature threshold,

select a reduced speed limit when the data indicates that real-time temperature is greater than the temperature threshold, wherein the reduced speed limit is less than the terminal speed limit, and

limit the torque output by at least one of the power source and the transmission to limit the speed of the vehicle to the selected one of the terminal speed limit and the reduced speed limit.

2. The system for managing a temperature of a working fluid in a vehicle powertrain according to claim 1, wherein the controller is further configured to,

compare the data from the temperature sensor to a second temperature threshold after the controller selects the reduced speed limit, wherein the second temperature threshold is less than the temperature threshold, and

select the terminal speed limit when the data indicates that real-time temperature is less than the second temperature threshold.

3. The system for managing a temperature of a working fluid in a vehicle powertrain according to claim 1, wherein the controller is further configured to,

compare the data from the temperature sensor to a second temperature threshold after the controller selects the reduced speed limit, wherein the second temperature threshold is less than the temperature threshold, and

select the reduced speed limit when the data indicates that real-time temperature is greater than or substantially equal to the second temperature threshold.

4. The system for managing a temperature of a working fluid in a vehicle powertrain according to claim 1, further comprising:

at least one speed sensor configured to output data indicative of a speed of the vehicle, wherein the controller is configured to,

compare the data from the speed sensor with the reduced speed limit, and limit the torque output by signaling the at least one of the power source and the transmission to gradually reduce the speed of the vehicle if the data from the speed sensor indicates that the speed of the vehicle is greater than the reduced speed limit.

5. The system for managing a temperature of a working fluid in a vehicle powertrain according to claim 1, wherein the controller is further configured to,

determine one of a nominal condition and a fault condition of the temperature sensor; and select the reduced maximum speed limit when the controller determines the fault condition.

6. The system for managing a temperature of a working fluid in a vehicle powertrain according to claim 5, further comprising:

a display in electrical communication with the controller, wherein the controller is configured to signal the display to issue at least one of a visual message and an audible message when the controller determines the fault condition.

7. The system for managing a temperature of a working fluid in a vehicle powertrain according to claim 5, wherein the controller is configured to compare the data from the temperature sensor to the temperature threshold when the controller determines the nominal condition.

8. The system for managing a temperature of a working fluid in a vehicle powertrain according to claim 1, wherein the controller is configured to limit the torque output by,

determining a target torque output for the at least one of the power source and the transmission; and

incrementally reducing the torque output of the at least one of the power source and the transmission to the target torque output in accordance with a proportional-integral-derivative analysis.

9. A method for managing a temperature of a working fluid in a vehicle powertrain, the vehicle powertrain including a power source configured to output torque and a transmission including the working fluid, the transmission selectively coupled to the power source and configured to multiply and output the torque from the power source, the method comprising: obtaining data indicative of a real-time temperature of the working fluid;

comparing the data to a temperature threshold;

selecting a terminal speed limit when the data is less than or substantially equal to the temperature threshold;

selecting a reduced speed limit when the data indicates that real-time temperature is greater than the temperature threshold, wherein the reduced speed limit is less than the terminal speed limit; and

limiting the torque output by at least one of the power source and the transmission to limit the speed of the vehicle to the selected one of the terminal speed limit and the reduced speed limit.

10. The method for managing a temperature of a working fluid in a vehicle powertrain according to claim 9, further comprising:

comparing the data to a second temperature threshold after selecting the reduced speed limit, wherein the second temperature threshold is less than the temperature threshold; and

selecting the terminal speed limit when the data indicates that real-time temperature is less than the second temperature threshold.

11. The method for managing a temperature of a working fluid in a vehicle powertrain according to claim 9, further comprising:

comparing the data to a second temperature threshold after selecting the reduced speed limit, wherein the second temperature threshold is less than the temperature threshold; and

selecting the reduced speed limit when the data indicates that real-time temperature is greater than or substantially equal to the second temperature threshold.

12. The method for managing a temperature of a working fluid in a vehicle powertrain according to claim 9, further comprising:

obtaining data indicative of a speed of the vehicle; and

comparing the speed data the reduced speed limit,

wherein limiting the torque output includes signaling the at least one of the power source and the transmission to gradually reduce the speed of the vehicle if the speed data indicates that the speed of the vehicle is greater than the reduced speed limit.

13. The method for managing a temperature of a working fluid in a vehicle powertrain according to claim 9, further comprising:

determining one of an nominal condition and a fault condition of the temperature data; and selecting the reduced maximum speed limit when the fault condition is determined.

14. The method for managing a temperature of a working fluid in a vehicle powertrain according to claim 13, further comprising:

issuing at least one of a visual message and an audible message when the fault condition is determined.

15. The method for managing a temperature of a working fluid in a vehicle powertrain according to claim 13, wherein comparing the data to the temperature threshold includes comparing the data to the temperature threshold when the nominal condition is determined.

16. The method for managing a temperature of a working fluid in a vehicle powertrain according to claim 9, wherein limiting the torque output includes,

determining a target torque output, and

incrementally reducing the torque output of at least one of the power source and the transmission to the target torque output in accordance with a proportional-integral-derivative analysis.