Methods and system for super positioning torque vectoring on a differential
Methods and systems are provided for controlling yaw of a vehicle while maintaining vehicle speed. In one example, equal and opposite vectoring torques are applied to first and second wheels along with a propulsion torque so that a vehicle yaw moment may be induced without accelerating or decelerating the vehicle.
1. A vehicle operating method, comprising:
requesting an increase in vectoring torque;
increasing a traction torque in response to the requested increase in vectoring torque while an accelerator pedal is not applied; and
increasing a torque applied via a wheel brake in response to the increase in vectoring torque.
2. The method of claim 1 , further comprising increasing a torque capacity of a second clutch in response to the increase in vectoring torque.
3. The method of claim 1 , further comprising operating a first clutch with zero torque capacity in response to the increase in vectoring torque.
4. The method of claim 1 , where the vectoring torque is a torque that generates yaw via an axle of a vehicle.
5. The method of claim 1 , where the traction torque is increased via increasing output of an electric machine or an internal combustion engine.
6. The method of claim 1 , where the wheel brake is a left wheel brake.
7. The method of claim 1 , further comprising maintaining a constant total axle torque based on accelerator pedal position.
8. A vehicle operating method, comprising:
commanding a driveline wheel torque that is a sum of a requested traction torque and a first portion of a requested vectoring torque;
commanding a first brake to generate a first brake torque, the first brake torque based on the first portion of the requested vectoring torque;
commanding a second brake to generate a second brake torque, the second brake torque based on the first portion of the requested vectoring torque;
commanding a first clutch to a first clutch torque capacity, the first clutch torque capacity based on a requested torque of a first wheel and the first portion of the requested vectoring torque; and
commanding a second clutch to a second clutch torque capacity, the second clutch torque capacity based on the first clutch torque capacity and the requested traction torque.
9. The method of claim 8 , where the first brake is a left brake, and where the second brake is a right brake.
10. The method of claim 8 , where first clutch is a left clutch, and where the second clutch is a right clutch.
11. The method of claim 8 , where the first wheel is a right wheel, and further comprising:
commanding a pressure of fluid supplied to first brake that is a function of a requested left wheel brake torque, a left_wheel_speed, a left wheel temperature; and
commanding a pressure of fluid supplied to second brake that is a function of a requested right wheel brake torque, a right wheel speed, and a right wheel temperature.
12. The method of claim 8 , where commanding a driveline wheel torque includes commanding an engine to generate the driveline wheel torque.
13. The method of claim 8 , where commanding a driveline wheel torque includes commanding an electric machine to generate the driveline wheel torque.
14. The method of claim 8 , where first portion of the requested vectoring torque is one half of the requested vectoring torque.
15. The method of claim 8 , where the vectoring torque is a torque for generating a yaw moment for a vehicle.
16. A vehicle system, comprising:
an accelerator pedal;
a propulsion source;
an axle system coupled to the propulsion source including a first wheel brake, a second wheel brake, a first clutch, and a second clutch; and
a controller including executable instructions stored in non-transitory memory to adjust torque output of the propulsion source in response to a position of the accelerator pedal and a vectoring torque, and further executable instructions stored in non-transitory memory to increase a torque capacity of the second clutch and apply a braking torque via the first wheel brake in response to the vectoring torque.
17. The vehicle system of claim 16 , where the vectoring torque is a torque that generates yaw of a vehicle.
18. The vehicle system of claim 16 , where the propulsion source is an electric machine.
19. The vehicle system of claim 16 , where the propulsion source is an internal combustion engine.
20. The vehicle system of claim 16 , further comprising additional executable instructions stored in non-transitory memory to increase torque output of the propulsion source in an amount equal to one half of the vectoring torque.