US Patent 7651440 Control of engine torque reduction at upshift initiation

An improved control for an automatically shiftable transmission upshift, wherein the engine output torque and on-coming clutch pressure are coordinated during the shift based on an inverse dynamic model of the transmission to achieve a desired output torque trajectory. At the initiation of an upshift, the engine torque is commanded to decrease in a ramp-like or sloping fashion to and engine output torque value calculated using the dynamic model. This ramp-like or sloping decrease provides smooth shifting, while reducing the likelihood of tie-up between on-coming and off-going clutches within the automatically shiftable transmission.