Research on Coordinated Control during Mode Transition in Hybrid Electric Vehicles

Abstract

<div class="section abstract"><div class="htmlview paragraph">Due to the objectives of achieving high fuel efficiency and drivability performance, a dual-drive hybrid system with two motors has been developed. Various drive modes are presented based on engine status, requested driver torque and power, as well as C0 status in different working conditions. The transition control of drive mode change poses a unique challenge for the dual-drive hybrid system. This study discusses the control strategies for transitioning between drive modes. The first type of transition mode is divided into four distinct phases. In the second mode transition, there are three phases: the synchronization phase involving P1 torque intervention, the C0 lock-up phase involving frozen P1 torque control and adjustment of C0 clutch torque and pressure correlation, and finally, the torque exchange phase. The third type of transition includes a dedicated torque transition phase followed by a C0 disengaged phase and concluding with a speed synchronization phase. Lastly, in the fourth transition scenario, as a safety measure, engine start is initiated by engaging the C0 clutch using the P2 motor when the P1 motor is in fault mode. Finally, successful real vehicle tests demonstrate significant improvement in drivability performance achieved through our innovative control strategy.</div></div>