Coordinated engine-start control of single-motor P2 hybrid electric vehicles with respect to different driving situations

Abstract

To cut down the costs caused by the additional starter, single-motor P2 hybrid electric vehicles (HEVs) make use of the driving motor to propel the vehicle as well as start the engine, and accordingly the engine-start control becomes more difficult. To satisfy the passengers' demands, this paper developed different coordinated engine-start control strategies with respect to different situations. First, a detailed model for the single-motor P2 HEVs system was built and related parameters were presented. Then, the coordinated engine-start control architecture for the internal combustion engine (ICE), engine disconnect clutch (EDC), electric motor (EM) and 8-speed automatic transmission (AT) was analyzed. Considering with the different driving situations, soft start strategy and dynamical start strategy are individually proposed. Through the simulation, the above control strategies were validated in accordance with their control objectives. Last, to optimize the trade-off between driving performance and riding comfort, some key parameters were further discussed. This work not only decreases the difficulty of engine-start control in the single-motor P2 HEVs but also is helpful to improve the quality of engine-start.