Hybrid electric vehicle propulsion system control

A hybrid electric vehicle (HEV), comprising:

• an internal combustion engine;
• an electric traction motor;
• a disconnect clutch selectively connecting the engine and the electric traction motor;
• a belt starter generator (BSG) unit configured to start the internal combustion engine;
• an engine control module (ECM) configured to manage engine speed control when the disconnect clutch is open;
• a hybrid supervisory control module (HCS) configured to manage engine speed control when the disconnect clutch is closed;
• and
• a powertrain control system, including the ECM and the HCS, for managing hybrid torque control authority transfer between the ECM and the HCS, the powertrain control system programmed to:
• turn the engine on;
• control, by the ECM, the engine to reach a predetermined target speed;
• close the disconnect clutch when the engine reaches the predetermined target speed;
• and
• transfer hybrid torque control authority from the ECM to the HCS by simultaneously reducing an ECM torque contribution and increasing an HCS torque contribution until the ECM torque contribution is zero.