Engine limit control for closed-throttle transmission shifting

This invention relates to closed-throttle shifting of an automatic transmission, and more particularly to an engine speed and torque rate limit control for ensuring high shift quality in spite of increases in the driver torque request. An improved engine and transmission control method for coordinated control of closed-throttle transmission shifting, wherein the transmission control provides engine speed and torque rate limits to the engine control based on the shift parameters. The speed and/or torque rate limits come into play if the driver suddenly increases the engine throttle setting. Additionally, in driver requested garage shifts, initiation of the shift is prevented until the engine speed is within the speed limit. Preferably, the engine speed limit is set a calibrated amount above the computed input synchronization speed (SYNC). Alternately, the engine speed limit may be set to a value that limits the energy dissipated in the on-coming clutch to a predetermined value. With either approach, the engine speed and torque limits modify the engine control only to the extent necessary to preserve high shift quality while limiting the on-coming clutch energy dissipation to a safe level.