System and method to reduce transfer clutch overheating

Patent metadata

Field	Value
Publication number	US-11685258-B1
Application number	US-202217849896-A
Country	US
Kind code	B1
Filing date	Jun 27, 2022
Priority date	Jun 27, 2022
Publication date	Jun 27, 2023
Grant date	Jun 27, 2023

Abstract

A system and method for controlling a torque transfer clutch of a vehicle. A first data source indicates if the clutch is in AWD or 4×4 mode. An integrator system monitors energy transferred across the clutch. A temperature data source measures or calculates the clutch temperature. In a first case, the integrator accumulates data of the energy across the clutch during a monitoring period that is compared to a maximum accumulated energy value and initiates a powertrain torque dependent transfer point learn routine. In a second case, the controller responds to energy accumulator cycle data in a single monitoring cycle that is compared to a maximum cycle data value. In a third case, the controller responds to clutch temperature data and compares the temperature data to a maximum temperature value. The second and third cases initiate a non-powertrain torque dependent transfer point learn routine.

First claim

What is claimed is:

1. A system for controlling a torque transfer clutch of a four-wheel drive vehicle comprising:
a first data input source that indicates if the torque transfer clutch is in a four-wheel drive mode;
an energy integrator system that monitors energy transferred across a transfer clutch;
a temperature data source provides transfer clutch temperature data; and
a controller programmed with an algorithm that controls the torque transfer clutch based in part on a transfer point value, wherein the algorithm:
in a first case responds to energy integrator accumulated data as to the energy across the torque transfer clutch during a monitoring period and compares the energy accumulator accumulated data to a maximum accumulated energy value by initiating a powertrain torque dependent transfer point learn routine,
in a second case responds to energy accumulator cycle data as to the energy across the torque transfer clutch in a single monitoring cycle and compares the energy accumulator cycle data to a maximum cycle data value by initiating a non-powertrain torque dependent transfer point learn routine,
in a third case responds to clutch temperature data and compares the clutch temperature data to a maximum temperature value by initiating the non-powertrain torque dependent transfer point learn routine;

wherein the controller, responsive to one of the above transfer point learn routines, revises the transfer point value to a revised transfer point value, wherein the controller controls the torque transfer clutch based upon the revised transfer point value.

2. The system of claim 1 wherein a monitoring period duration is a value programmed into the controller.

3. The system of claim 1 wherein the controller responds to a mode selector indicating that the system is in a high-capacity mode by initiating the energy integrator system, resetting a monitoring period timer to zero, and resetting the energy integrator accumulated data to zero.

4. The system of claim 1 wherein the controller responds to a mode selector indicating that the system is in a low-capacity mode by disabling the energy integrator system.

5. The system of claim 1 wherein the energy integrator system monitors the energy across a transfer clutch based on slippage of the torque transfer clutch and provides cycle data.

6. The system of claim 5 wherein the energy transferred across the transfer clutch is accumulated by the controller over the monitoring period.

7. The system of claim 1 further comprising:
a powertrain torque measuring system that provides powertrain torque data that is compared to a powertrain torque threshold value, wherein the powertrain torque dependent transfer point learn routine is deferred if the powertrain torque data is less than the powertrain torque threshold value.

8. The system of claim 1 wherein the non-powertrain torque dependent transfer point learn routine is initiated immediately.

9. The system of claim 1 wherein during a transfer point learn routine, clutch cycle data is not accumulated.

10. The system of claim 1 further comprising:
a vehicle speed monitoring system that provides vehicle speed data to the controller and compares the vehicle speed data to a threshold vehicle speed value, wherein clutch cycle data is not accumulated if the vehicle speed data is less than the threshold vehicle speed value.

11. The system of claim 1 further comprising:
a cool down delay timer that is incremented in the third case after the transfer point learn routine is triggered, wherein the cool down delay timer time value is compared to a cool down threshold time value and if the cool down threshold time value has not been reached, the controller increments the cool down delay timer and clutch cycle data is not accumulated until the cool down delay timer time value reaches the cool down threshold time value.

12. A method for controlling a torque transfer clutch of a four-wheel drive vehicle comprising:
monitoring a first data input source that indicates if the torque transfer clutch is in a four-wheel drive mode;
monitoring an energy integrator system that monitors energy transferred across a transfer clutch and provides energy accumulator cycle data;
monitoring a temperature data source that measures a torque transfer clutch temperature and provides clutch temperature data;
accumulating energy accumulator cycle data provided to a controller programmed with an algorithm that controls the torque transfer clutch based in part on a transfer point value, wherein the algorithm;
comparing in the controller in a first case during a monitoring period energy accumulator cycle data to a maximum accumulated energy value and requesting a powertrain torque dependent transfer point learn routine if the energy accumulator cycle data is greater than the maximum accumulated energy value;
comparing in the controller in a second case energy accumulator cycle data to a maximum energy accumulator cycle data value by requesting a non-powertrain torque dependent transfer point learn routine if the energy accumulator cycle data is greater than the maximum energy accumulator cycle data value; and
comparing in the controller in a third case clutch temperature data to a maximum clutch temperature value and initiating a non-powertrain torque dependent transfer point learn routine if the clutch temperature data is greater than the maximum clutch temperature value;
wherein the controller, responsive to one of the above transfer point learn routines, revises the transfer point value to a revised transfer point value, and wherein the controller controls the torque transfer clutch based upon the revised transfer point value.

13. The method of claim 12 further comprising:
responding in the controller to a mode selector indicating that the torque transfer clutch is in a high capacity mode by initiating the energy integrator system, resetting a monitoring period timer to zero, and resetting energy integrator accumulated data to zero.

14. The method of claim 12 further comprising:
monitoring the energy across a transfer clutch based on slippage of the torque transfer clutch by the energy integrator system, wherein the energy integrator system provides the energy accumulator cycle data.

15. The method of claim 14 further comprising:
accumulating the energy accumulator cycle data by the controller over a monitoring period.

16. The method of claim 12 further comprising:
deferring initiating the powertrain torque dependent transfer point learn routine, based upon a powertrain torque measuring system that provides powertrain torque data that is compared to a powertrain torque threshold value, if the powertrain torque data is less than the powertrain torque threshold value.

17. The method of claim 12 further comprising:
deferring initiating the powertrain torque dependent transfer point learn routine, based upon a powertrain torque measuring system that provides powertrain torque data that is compared to a powertrain torque threshold value, if the powertrain torque data is less than the powertrain torque threshold value.

18. The method of claim 12 further comprising:
initiating the non-powertrain torque dependent transfer point learn routine immediately.

19. The method of claim 12 wherein during a transfer point learn routine the energy accumulator cycle data is not accumulated.

20. A system for controlling a torque transfer clutch of a four-wheel drive vehicle comprising:
an energy integrator system that monitors the energy tr

Assignees

• Ford Global Tech Llc

Inventors

• Harriman Ii Douglas
• Frey Michael
• Tomik Filip
• Riedle Bradley D
• Chagnon Peter

Classifications

• B60W2510/0291

  Clutch temperature · CPC title

• B60K23/0808

  for varying torque distribution between driven axles, e.g. by transfer clutch · CPC title

• F16D2500/30406

  Clutch slip · CPC title

• F16D48/06 Primary

  Control by electric or electronic means, e.g. of fluid pressure · CPC title

• B60W2510/0275

  Clutch torque · CPC title