Powertrain and method of coordinating chassis and propulsion system torque limits

Patent metadata

Field	Value
Publication number	US-10029669-B2
Application number	US-201514942035-A
Country	US
Kind code	B2
Filing date	Nov 16, 2015
Priority date	Nov 16, 2015
Publication date	Jul 24, 2018
Grant date	Jul 24, 2018

Abstract

A powertrain includes a propulsion system having first and second torque sources, and first and second drive axles respectively connected to and independently driven by the first and second torque sources. A permissible range of torque contribution from the torque sources to the respective first and second drive axles is defined by a component torque window. The powertrain includes sensors for detecting a dynamic driving maneuver of a vehicle having the powertrain. A controller executes a method to adjust a size and/or orientation of a chassis torque window during the detected dynamic driving maneuver, determine an optimally efficient axle torque operating point that falls on a torque line within the component torque window in proximity to the chassis torque window, and command the torque contribution via transmission of torque control signals to the first and second torque sources to achieve the optimally efficient axle torque operating point.

First claim

What is claimed is:

1. A powertrain system comprising:
a propulsion system having first and second torque sources responsive to a driver-requested torque, wherein a torque line defines a two-dimensional range of theoretically-attainable torque distributions from the first and second drive sources meeting the driver-requested torque;
first and second drive axles that are respectively connected to and independently driven by the first and second torque sources, wherein a permissible range of torque contribution from the first and second torque sources to the respective first and second drive axles is defined by a component torque window;
a plurality of sensors operable for detecting a dynamic driving maneuver of a vehicle having the powertrain; and
a controller programmed to automatically adjust at least one of a size and an orientation of a chassis torque window during the detected dynamic driving maneuver, the chassis torque window defining dynamics-based torque limits of the first and second torque sources, to determine an optimally efficient axle torque operating point that falls on the torque line within the component torque window at an intersection of boundaries of the component torque window and the torque line in a closest-attainable proximity to the chassis torque window, such that the controller is configured to selectively violate the chassis torque window, and to command a torque contribution from the first and second torque sources, via transmission of torque control signals to the first and second torque sources to achieve the optimally efficient axle torque operating point.

2. The powertrain system of claim 1 , wherein the controller is programmed to selectively adjust the torque contribution from the first and second torque sources by commanding a reduction in a torque commanded by the torque control signals to at least one of the first and second drive axles.

3. The powertrain system of claim 1 , wherein the plurality of sensors includes a plurality of speed sensors, a yaw rate sensor, and a steering angle sensor.

4. The powertrain system of claim 1 , wherein the controller is operable for receiving a selected driving mode from a drive mode selection device, and for adjusting the torque contribution from the first and second torque sources in response to the selected driving mode such that the optimally efficient axle torque operating point falls entirely outside of the chassis torque window.

5. The powertrain system of claim 1 , further comprising an energy storage system having a state of charge, wherein the controller is programmed to adjust the torque contribution from the first and second torque sources in response to the state of charge.

6. The powertrain system of claim 5 , wherein the controller is programmed to adjust the torque contribution from the first and second torque sources such that the optimally efficient axle torque operating point falls entirely outside of the chassis torque window.

7. The powertrain system of claim 1 , wherein the first and second torque sources include an electric machine.

8. The powertrain system of claim 7 , wherein the first and second torque sources include an internal combustion engine.

9. The powertrain system of claim 1 , wherein the controller is programmed to selectively adjust the output torque contribution from the first and second torque sources in response to a selected driving mode from a driving mode selection device such that the optimally efficient axle torque operating point falls within the chassis torque window during the dynamic driving maneuver.

10. The powertrain system of claim 1 , wherein the controller is operable for detecting slip of a road wheel of one of the first or second drive axles, and to limit, via the torque control signals, a maximum allowed axle torque to the first or second drive axles having the detected slip.

11. A method for coordinating torque limits of a chassis and a propulsion system of a vehicle having first and second drive axles, wherein the propulsion system includes first and second torque sources respectively connected to and independently powering the first and second drive axles and responsive to a driver-requested torque, wherein a torque line defines a two-dimensional range of theoretically-attainable torque distributions from the first and second drive axles meeting the driver-requested torque, and wherein a permissible range of a torque contribution of the first and second torque sources to the respective first and second drive axles is defined by a component torque window, the method comprising:
adjusting at least one of a size and orientation of a chassis torque window via a controller during a dynamic driving maneuver, the chassis torque window defining dynamics-based torque limits of the first and second torque sources;
determining an optimally efficient axle torque operating point that falls on the torque line within the component torque window at an intersection of boundaries of the component torque window and the torque line in a closest-attainable proximity to the chassis torque window, such that the controller is configured to selectively violate the chassis torque window; and
selectively adjusting a torque contribution from the first and second torque sources, via transmission of torque control signals from the controller to the first and second torque sources, to achieve the optimally efficient axle torque operating point.

12. The method of claim 11 , wherein selectively adjusting the torque contribution includes commanding a reduction in a torque command to at least one of the first and second torque sources via the torque control signals.

13. The method of claim 11 , further comprising detecting the dynamic driving maneuver using a plurality of sensors including speed sensors, a yaw rate sensor, and a steering angle sensor.

14. The method of claim 11 , wherein the vehicle includes an energy storage system having a state of charge, and wherein selectively adjusting the torque contribution occurs in response to the state of charge.

15. The method of claim 14 , wherein selectively adjusting the torque contribution in response to the state of charge occurs such that the optimally efficient axle torque operating point falls entirely outside of the chassis torque window.

16. The method of claim 11 , wherein selectively adjusting the torque contribution from the first and second torque sources occurs in response to receiving a selected driving mode signal from a driving mode selection device.

17. The method of claim 16 , wherein selectively adjusting the torque contribution from the first and second torque sources in response to the selected driving mode includes setting the optimally efficient axle operating point entirely outside of the chassis torque window.

18. The method of claim 16 , wherein selectively adjusting the torque contribution in response to the selected driving mode occurs such that the optimally efficient axle torque operating point falls within the chassis torque window during the dynamic driving maneuver.

19. The method of claim 11 , wherein the first and second torque sources are an internal combustion engine and an electric machine.

20. The method of claim 11 , wherein each of the first and second drive axles include a road wheel, the method further comprising detecting slip of one of the road wheels, wherein selectively adjusting the torque contribution includes limiting, via the torque control signals, a maximum allowed axle torque to the first or second drive axles having the road whee

Assignees

• Gm Global Tech Operations Llc

Inventors

• Mao Xiaofeng
• Klingler Thomas A
• Krueger Eric E
• Cawthorne William R
• Schwenke R Travis
• Mrdeza Scott C

Classifications

• B60K6/52

  Driving a plurality of drive axles, e.g. four-wheel drive · CPC title

• B60W10/06 Primary

  including control of combustion engines · CPC title

• B60W2710/244

  Charge state · CPC title

• B60W30/02

  Control of vehicle driving stability · CPC title

• B60W2540/18

  Steering angle · CPC title