Driver scheduled vehicle coast downshift control and shift diagnostic techniques

摘要

Systems and methods for a vehicle automatic transmission comprising a dog clutch utilize a set of sensors configured to measure accelerator pedal position, torque generating device speed, and vehicle speed, and a controller configured to detect whether a coast downshift of the transmission to a desired gear ratio and involving the dog clutch is to be performed. In response to detecting that the coast downshift involving the dog clutch is to be performed, the controller determines whether the accelerator pedal has been depressed indicating a request for increased torque generating device speed/torque, when the accelerator pedal is depressed, performs a downshift of the transmission, while the accelerator pedal is not depressed, determines whether a synchronization point of the vehicle speed relative to the torque generating device speed has been reached and when the vehicle/torque generating device speed synchronization point has been reached, performs the downshift of the transmission.