A transmission of a vehicle multiplies and transfers drive torque from an input shaft of a torque generating device (an engine, an electric motor, etc.) to a driveline. For an automatic transmission, a gear ratio of a planetary gear set is selected by supplying hydraulic pressure to on-coming and off-going clutches. For a coast downshift, the vehicle is decelerating and the downshift is scheduled and performed based on various vehicle operating parameters. This coast downshift can use positive torque from the torque generating device, which could be perceived by the driver of the vehicle as noise/vibration/harshness (NVH). This controller-based shift patterning is also potentially undesirable to a driver who may not want the transmission to downshift. Accordingly, while such automatic transmission systems work well for their intended purpose, there remains a need for improvement in the relevant art.
USPTO Backgrounds
USPTO Backgrounds