Method of controlling regeneration and boost functions of a hybrid powertrain

A vehicle comprising:

• an internal combustion engine;
• an electric device selectively coupled to the internal combustion, and operable in at least a boost operating mode and a regenerative operating mode;
• at least one energy storage device selectively coupled to the electric device;
• and
• a hybrid system controller operably coupled to the internal combustion engine, the electric device, and the at least one energy storage device;
• wherein the hybrid system controller includes a processor, a memory, and at least one algorithm stored on the memory of the hybrid system controller, with the at least one algorithm executable by the processor to:
• select one of either the boost operating mode or the regenerative operating mode for the electric device;
• calculate an operating efficiency of the electric device;
• compare the operating efficiency of the electric device to an upper Motor-generator-inverter (MGI) efficiency threshold to determine if the operating efficiency of the electric device is equal to or greater than the upper MGI efficiency threshold, or if the operating efficiency of the electric device is less than the upper MGI efficiency threshold, when the boost operating mode is selected;
• control the electric device to operate the electric device in the boost operating mode when the operating efficiency of the electric device is equal to or greater than the upper MGI efficiency threshold, wherein the electric device draws electrical power from the at least one energy storage device for generating torque for the internal combustion engine;
• compare the operating efficiency of the electric device to a lower MGI efficiency threshold to determine if the operating efficiency of the electric device is equal to or greater than the lower MGI efficiency threshold, or if the operating efficiency of the electric device is less than the lower MGI efficiency threshold, when the regenerative operating mode is selected;
• and
• control the electric device to operate the electric device in the regenerative operating mode when the operating efficiency of the electric device is equal to or greater than the lower MGI efficiency threshold, wherein the electric device receives torque from the internal combustion engine for generating electricity for charging the at least one energy storage device when operating in the regenerative operating mode.