Automatic transmission synchronous gear shift

摘要

A method of commanding a synchronous gear shift begins by receiving a request to shift from a third gear to a first gear, and skipping a second gear having a gear ratio between the gear ratio of the first gear and the gear ratio of the third gear. Subsequently the method includes: reducing a torque command to a predetermined value; opening a clutch disposed on the input shaft of the transmission to decouple the transmission from the engine; transitioning the engine from a torque-control mode into a speed-control mode; commanding the engine to rotate at a speed dictated by the motion of the vehicle and the gear ratio of the first gear; closing the clutch to couple the transmission and the engine; and transitioning the engine back into the torque-control mode.

主权项

1. A method of commanding a synchronous gear shift in a vehicle powertrain that includes an engine and a transmission having a plurality of ordered gears, the method comprising:
receiving a request to shift from a third gear to a first gear, and skipping a second gear having a gear ratio between the gear ratio of the first gear and the gear ratio of the third gear; reducing a torque command to a predetermined value; opening a clutch disposed on an input shaft of the transmission to decouple the transmission from the engine; transitioning the engine from a torque-control mode into a speed-control mode; commanding the engine, while in the speed-control mode, to rotate at a speed dictated by the motion of the vehicle and the gear ratio of the first gear; closing the clutch to couple the transmission and the engine; and transitioning the engine back into the torque-control mode.