Abstract: A method of operating a brake-retract system during a regenerative braking event begins with monitoring an amount of regenerative braking achieved. A set point threshold is linearly ramped from a first threshold to a max regeneration capacity if the amount of regenerative braking achieved exceeds a second threshold. The second threshold is less than the first threshold, and the first threshold is less than the max regeneration capacity. The max regeneration capacity is representative of a maximum amount of regenerative braking capable of being produced. A friction element is transitioned from a first, retracted-state to a second, ready-state if the amount of regenerative braking achieved exceeds the set point threshold.

Abstract: A method of operating a brake-retract system during a regenerative braking event begins with monitoring an amount of regenerative braking achieved. A set point threshold is linearly ramped from a first threshold to a max regeneration capacity if the amount of regenerative braking achieved exceeds a second threshold. The second threshold is less than the first threshold, and the first threshold is less than the max regeneration capacity. The max regeneration capacity is representative of a maximum amount of regenerative braking capable of being produced. A friction element is transitioned from a first, retracted-state to a second, ready-state if the amount of regenerative braking achieved exceeds the set point threshold.

Abstract: A hybrid powertrain includes and internal combustion engine, an energy storage device, an electro-mechanical transmission having at least one electric machine rotatably coupled to the engine. The electro-mechanical transmission is selectively controllably operative to transmit torque among the engine and the at least one electric machine. A method to start operation of the internal combustion engine includes initiating rotation of a crankshaft of the engine with the at least one electric machine until a first predetermined crankshaft speed is achieved, firing the engine while controlling engine speed with the at least one electric machine until a flare threshold occurs, controlling the engine speed without any interaction from the at least one electric machine based on controlling combustion parameters of the engine, and when a predetermined condition occurs, controlling the engine speed with the at least one electric machine while the engine is still firing.

Abstract: A hybrid powertrain includes and internal combustion engine, an energy storage device, an electro-mechanical transmission having at least one electric machine rotatably coupled to the engine. The electro-mechanical transmission is selectively controllably operative to transmit torque among the engine and the at least one electric machine. A method to start operation of the internal combustion engine includes initiating rotation of a crankshaft of the engine with the at least one electric machine until a first predetermined crankshaft speed is achieved, firing the engine while controlling engine speed with the at least one electric machine until a flare threshold occurs, controlling the engine speed without any interaction from the at least one electric machine based on controlling combustion parameters of the engine, and when a predetermined condition occurs, controlling the engine speed with the at least one electric machine while the engine is still firing.

Abstract: A method to monitor integrity of a motor torque command for a transmission in a hybrid powertrain system includes calculating motor torque commands for the torque generating machines. Torque corrections for the motor torque commands are determined. The motor torque commands are adjusted based upon the torque corrections. The adjusted motor torque commands are verified based upon an estimated output torque.

Abstract: Controlling a hybrid powertrain includes monitoring an operator torque request, determining maximum and minimum allowable transmission output torques based upon the operator torque request, determining a commanded transmission output torque, and comparing the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques.

Abstract: A method to monitor integrity of a motor torque command for a transmission in a hybrid powertrain system includes calculating motor torque commands for the torque generating machines. Torque corrections for the motor torque commands are determined. The motor torque commands are adjusted based upon the torque corrections. The adjusted motor torque commands are verified based upon an estimated output torque.

Abstract: Controlling a hybrid powertrain includes monitoring an operator torque request, determining maximum and minimum allowable transmission output torques based upon the operator torque request, determining a commanded transmission output torque, and comparing the commanded transmission output torque and each of the maximum and minimum allowable transmission output torques.