Method and system for improving fuel economy of a hybrid powertrain in a vehicle

A method of improving fuel economy and reducing emissions of a vehicle with an electric motor, an engine and an energy storage device, the method comprising:

• determining, by a system control unit, that the vehicle is stopped;
• obtaining, by the system control unit, lookahead information and current state information, wherein the lookahead information includes a predicted stop time, a predicted power demand, and a predicted catalyst temperature and the current state information includes a current catalyst temperature, a catalyst response time, and a current engine state;
• determining, by the system control unit based on the lookahead information and the current state information, a target engine state and a target engine load;
• and
• controlling, by the system control unit, the engine to meet the target engine state and the target engine load.

A vehicle system comprising:

• an engine;
• an electric motor;
• an energy storage device coupled with the electric motor;
• and
• a controller configured to:
• obtain lookahead information and current state information, wherein the lookahead information includes a predicted catalyst temperature, and the current state information includes a current catalyst temperature and a current SOC for the energy storage device;
• determine, based on the lookahead information and the current state information, a target power split between the energy storage device and the engine;
• and
• control, based on the predicted catalyst temperature and a difference between the current SOC and the target SOC, a load applied to the engine for the energy storage device to meet a power level defined by the target power split.

A vehicle system comprising:

• an engine;
• an electric motor;
• an energy storage device coupled with the electric motor;
• and
• a controller configured to:
• determine that the vehicle system is stopped;
• obtain lookahead information and current state information, wherein the lookahead information includes a predicted stop time, a predicted power demand, and a predicted catalyst temperature and the current state information includes a current catalyst temperature, a catalyst response time, and a current engine state;
• determine, based on the lookahead information and the current state information, a target engine state and a target engine load;
• and
• control the engine to meet the target engine state and the target engine load.