Patent ID: 8755960

Claim:
Method for controlling a hybrid powertrain system including an internal combustion engine and a torque machine wherein electrical energy is controllably transferred between an electric energy storage device and the torque machine by a control system, said control system executing the following steps comprising: monitoring magnitudes of an actual voltage, an actual current, and an actual power output of the electric energy storage device; executing, using a central processing unit, a battery power control scheme to control the output power of the electric energy storage device associated with the electrical energy transferred between the electric energy storage device and the torque machine, comprising: setting a trigger voltage limit at a first voltage value below a base voltage limit, said base voltage limit defining an operating range for the voltage of the electrical energy storage device, when the monitored magnitude of actual power is not exceeding a preferred power limit, setting a magnitude of maximum and minimum tactical control power constraints of the electric energy storage device equal to the preferred power limit, when the monitored magnitude of actual voltage is less than the trigger voltage limit, setting a preferred voltage limit to an initial value based on a second voltage value between the base voltage limit and the trigger voltage limit, when the monitored magnitude of actual voltage exceeds the trigger voltage limit, increasing a magnitude of the preferred voltage limit at a predetermined rate from the initial value until the preferred voltage limit reaches the base voltage limit when the monitored magnitude of actual voltage exceeds the magnitude of the preferred voltage limit, one of increasing the minimum tactical control power constraint by a positive change rate value without adjusting the maximum tactical control power constraint, and decreasing the maximum tactical control power constraint by a negative change rate value without adjusting the minimum tactical control power constraint; disabling, using a central processing unit, the battery power control scheme when the control system loses a power limit authority associated with the electrical energy transferred between the electric storage device and the torque machine during ongoing operation, wherein said loss of the power limit authority results from a loss of control of output torque from the hybrid powertrain system, comprising one of: if the minimum tactical control power constraint was increased by the positive change rate value, ramping down the minimum tactical control power constraint to the magnitude equal to the preferred power limit, and if the maximum tactical control power constraint was decreased by the negative change rate value, ramping up the maximum tactical control power constraint to the magnitude equal to the preferred power limit; and re-enabling the battery power control scheme when the control system regains the power limit authority.