针对干式双离合自动变速器(DCT)弱混合动力轿车,为改善换挡品质(缩短换挡时间并减少换挡冲击),对集成启动机/发电机(ISG)介入换挡过程离合器传递转矩和不同动力源输出转矩协调控制问题进行了研究。首先,建立了DCT换挡切换过程动力学方程,通过量化驾驶意图得到了车辆目标加速度,设计了转矩相分离离合器分离规律,计算并得到了离合器传递转矩;然后,利用基于模型的预测控制对发动机(ISG)转速进行实时优化,实现了接合离合器主、从动盘转速快速同步;在需求转矩切换阶段,将发动机转矩切换到驾驶人需求水平,ISG电机逐渐退出换挡过程;最后,考虑到ISG电机输出转矩能力限制,对动力源转矩进行分配。仿真结果表明:所提出的转矩协调控制策略解决了DCT换挡过程中双离合器、发动机与ISG电机间的实时转矩协调控制问题,为DCT在混合动力轿车上的应用奠定了基础。
As for the hybrid vehicle equipped with dry dual clutch transmission (DCT), the coordinating control problem of clutch transmission torque and power source output torque was researched to improve the shifting performance (shorting the shift time and jerk intensity), when integrated starter generator (ISG) involved in the shifting process was considered. First of all, the dynamic equation of DCT shifting process was established, the vehicle target acceleration was obtained through quantifying the driving intension and the torque transmitted by clutch was calculated according to the designed disengaging principle in the torque phase. Then the model predictive control was applied to optimize ISG speed and realize the speed synchronization between the clutch driving and driven plates. In the demand torque switch phase, engine torque was switched to the demand torque of driver and ISG torque exited gradually from shifting process. At last, the torque of power sources was distributed in consideration of constraint ISG output torque capacity. The simulation results show that the proposed torque coordinating control strategies solve the real-time torque coordinating problems among dual clutch, engine and ISG motor in DCT shifting process, laying a foundation for the application of DCT in hybrid cars.