FIELD

The present description relates generally to methods and systems for applying torque vectoring to a vehicle for the purpose of inducing a yaw moment on the vehicle. The methods and systems may be particularly useful for vehicles that include a differential or axle having a pair of clutches.

BACKGROUND/SUMMARY

It may be desirable to generate a vehicle yaw moment from time to time to improve vehicle handling and/or stability. One way to introduce a vehicle yaw moment may be to apply a clutch of an axle or differential clutch when power is being delivered from an internal combustion engine to the axle. By applying the clutch, a torque difference between a left wheel and a right wheel may be generated, thereby inducing a vehicle yaw moment. However, inducing a vehicle yaw moment in this way has limitations. In particular, because this method distributes engine torque to generate the vehicle yaw moment, a vehicle yaw moment may not be generated when there is lack of engine torque. Consequently, when an accelerator pedal of the vehicle is released, it may be difficult to generate a desired or requested vehicle yaw moment.

The inventors herein have recognized the above-mentioned issues and have developed 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.

By applying super positioning torque vectoring, it may be possible to provide a vehicle yaw moment even during conditions when driver demand torque (e.g., may also be referred to as a requested traction torque) is low or zero. In particular, equal and opposite vectoring torques may be applied to left and right wheels while also providing propulsion torque to the left and right wheels so that a vehicle yaw moment may be induced even when driver demand torque is low or zero. Super positioning torque vectoring may include adjusting a torque of a propulsion source, axle or differential clutch torque capacities, and torques applied by friction brakes. Super positioning torque vectoring also allows a vehicle yaw moment to be generated when the driver demand torque is higher and non-zero.

The present description may provide several advantages. In particular, the approach may provide vehicle yaw moment control when driver demand wheel torque is low or high. Further, the approach may be implemented on existing vehicle systems. In addition, the approach may be applied to electric vehicles, hybrid vehicles, and vehicles having internal combustion engines.

It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

