Due to the special structure characteristics, the switching process control from pure electrical driving mode to compound driving mode of the single-shaft parallel hybrid powertrain has caught broad attentions from related researches. In this study, a novel mode transition control method based on model predictive control algorithm is proposed to regulate the starting and engaging processes into driveline of the engine via an automatic clutch. According to the system states evolution process, the system control commands, that is, the immediate output torques of the engine, the motor, and the clutch during the mode transition process, are determined online by the proposed model predictive control controller, which derives the optimal control sequences to minimize the defined objective function by adopting quadratic programming in the prediction horizon. To better demonstrate the efficacy of the proposed control method, a simulation analysis platform is built based on MATLAB/Simulink and AVL/Cruise. Simulation results show that the coordinated control method can effectively suppress the vehicle longitudinal jerk within the reasonable range and reduce the clutch wear loss during the mode transition process.

Hybrid electric vehicles with in-wheel motors (IWM) achieve a variety of driving modes by two power sources—the engine and the IWM. One of the critical problems that exists in such vehicle is the different transient characteristics between the engine and the IWM. Therefore, switching processes between the power sources have noteworthy impacts on vehicle dynamics and driving performance. For the particular switching process of the pure electric mode to the engine driving mode, a specific control strategy coordinating clutch torque, motor torque, and engine torque was proposed to solve drivability issues caused by inconsistent responses of different power sources during the mode transition. The specific switching process could be described as follows: the engine was started by IWM with the clutch serving as a key enabling actuator, dynamic torque compensation through IWM was implemented after engine started, and, meanwhile, engine speed was controlled to track the target speed through the closed loop PID control strategy. The bench tests results showed that the vehicle jerk caused during mode switching was reduced and fast and smooth mode switching was realized, which leads to the improvement of vehicle’s riding comfort.