自动变速器动力降挡过程控制的研究

摘要

虽然大多数车辆实际行驶时降挡过程中变速器的正向驱动转矩很小或为零，但当重型车满载爬坡时，往往须要进行动力降挡，为此，本文中对重型车动力不中断降挡控制进行研究。首先，建立动力传动系统模型，对降挡过程进行动力学分析，提出自动变速器动力降挡过程控制方法；接着，以惯性相时涡轮轴角加速度恒定作为参考模型，制定自适应控制策略，以提高控制策略的鲁棒性；最后进行满载爬坡实车试验。结果表明，动力降挡过程控制能有效提高换挡品质和车辆驾驶性能。%Though the driving torque of transmission is trivial or even zero in the downshift process of prac-tical driving for majority vehicles, but in the condition of full load hill climbing for heavy-duty vehicles, power-on downshift is often necessary. Accordingly, the downshift control without power interruption for heavy-duty vehicles is studied in this paper. Firstly the model for powertriain system is set up and a control scheme for the power-on down-shift process of automatic transmission is proposed based on a dynamics analysis of downshift process. Then with a constant angular acceleration of turbine shaft in the inertia phase of shifting process as reference model, an adaptive control strategy is worked out for enhancing its robustness. Finally a real vehicle hill climbing test with full load is conducted. The results show that power-on downshift control can effectively enhance the shifting quality and driving performance of vehicles.