Patent ID: 9216728
Filing Date: 2015-12-22
Classification: B60W,Y02T,Y10T

Abstract:
1. A method of carrying out a coasting downshift that involves an interlocking shifting element arranged in an automatic transmission, the automatic transmission further including a torque converter having a disengageable torque converter lockup clutch for adjusting torque transmitted between an engine and the automatic transmission, the method comprising the steps of: commencing the coasting downshift associated with the interlocking shifting element in order to initiate engagement of the interlocking shifting element, at a beginning of the coasting downshift, either fully or partially disengaging the torque converter lockup clutch for either fully or partially decoupling a driving connection between a drive-train, including the transmission, and the engine and allowing a turbine rotational speed to fall below an engine rotational speed, reaching a synchronous point for the interlocking shifting element, and only once the engine rotational speed falls below the turbine rotational speed and the synchronous point for the interlocking shifting element is reached, then engaging the interlocking shifting element and re-engaging the torque converter lockup clutch to re-couple the driving connection of the engine to the drivetrain.