A method for providing traction control in vehicle powertrain systems is
particularly adapted for traction control in a powertrain system of a
hybrid electric vehicle comprising an internal combustion engine, an
electric machine and a transmission that is operatively coupled to the
electric machine and the engine and adapted to provide a transmission
torque output in response to a transmission torque input received as a
torque output from either or both of the engine and the electric machine.
The method is adapted to utilize conventional traction control and engine
control hardware, software and communication standards to implement
traction control. In one embodiment of the invention, a conventional
traction controller is used to detect a wheel spin condition and provide
a plurality of first output torque command messages in response thereto.
The plurality of first output torque command messages are used to obtain
a torque reduction which is applied to a reference output torque to
obtain a corresponding plurality of traction control output torque
commands for the powertrain system during the wheel spin condition. A
rate limit may also be applied to control the rate of change between
successive ones of the traction control output torque commands in order
to reduce the possibility of extension of the wheel spin condition, or
recurrence of another wheel spin condition. Each traction control output
torque command may be used to determine an associated traction control
engine torque output command and traction control electric machine torque
output command.