Research on energy management based on SOC in P2.5 hybrid vehicles

The energy management strategy of the P2.5 hybrid system is based on the battery SOC limit management, which includes the battery power limitation, the motor charge, discharge torque management and the engine start request. The charge torque override conditions are defined for the low fuel consumption or battery health according to the special working conditions below: (1) The catalyst heat condition. To decrease the battery heat time and extend the battery health life, the battery heat condition energy management strategy is defined. (2) The battery heat condition. To enhance the performance of fuel consumption and emission during the catalyst heat phase, the catalyst heat phase energy management strategy is defined. (3) The low speed and low torque condition. To improve the efficiency of the engine and the response of the system and to avoid the drop of engine speed, energy management strategy is defined. The vehicle results are conducted and show that the energy management control can be decreased the fuel consumption by 26.15% compared to the traditional vehicles. The motor torque override strategy can also meet the driver torque by the motor and avoid the drop of the engine speed. The control of the catalyst heat phase can do good to fuel consumption.