Abstract: There is inevitably a gap in the vehicle power transmission system, especially in the urban driving process, the brake pedal and the accelerator pedal are frequently switched, stepping on the accelerator pedal during coasting downshifting will often induce serious shift shock problems. This article analyzes the reason of the impact from the hardware structure and control principle as the direction switching of the drive train. Through the control strategy and calibration optimization, the drive direction is actively switched during the gear shifting process, the feasibility of the strategy is verified by the actual vehicle test. And it has been promoted on related models.

Key words: Double clutch transmission; Driveline clearance; Coast downshift to force downshift; Shift quality

摘要： 车辆动力传动系统中不可避免地存在间隙，特别是在市区行车过程中，刹车踏板与油门间频繁切换，在滑 行降挡过程中踩油门往往会诱发严重的换挡冲击问题。文章从硬件结构和控制原理上分析了冲击原因为传动系方向切换，通过控制策略及标定优化，在换挡过程中主动切换传动方向，并进行了实车验证，证明了该策略的可行性，并在相关车型上得到推广。

关键词: 双离合变速器；传动系间隙；滑行降挡转动力降挡；换挡品质