Patent ID: 8510005
Filing Date: 2013-08-13
Classification: F16H

Abstract:
1. A method for controlling the torque phase of a clutch-to-clutch power downshift in a vehicle having a transmission and a torque converter, the method comprising: determining, during a near sync boost (NSB) state of the power downshift, a synchronization speed of an offgoing clutch and an oncoming clutch of the transmission, wherein the NSB state is a portion of the torque phase that occurs prior to the offgoing and oncoming clutches reaching synchronous speed (sync speed); estimating, via a controller, a feed-forward clutch pressure that holds a turbine speed of the torque converter at the sync speed; ramping a clutch pressure command to the oncoming clutch to the estimated feed-forward clutch pressure; and initiating closed-loop proportional-integral-derivative (PID) control over the clutch pressure command during the NSB state in response to a predetermined PID activation event.