Abstract: In a vehicle provided with an automatic transmission, gear-shifting shock is suppressed by changing the engine output power in response to a gear-shifting. The change in the engine output power is terminated when the actual engine speed reaches a completion decision engine speed, which is determined so that it corresponds to the time when the gear-shifting is completed, which is based on the fact that the engine speed changes according to a certain characteristic curve during the gear-shifting. The engine speed at which the gear-shifting is actually completed is detected for each gear-shifting according to the change in the rotational speed of the engine during the gear-shifting, and the completion decision rotational speed for each gear-shifting is set through learning on the basis of the preceding engine speed at which the gear shifting was actually completed.

Abstract: A vehicle is provided with an engine and an automatic transmission having a lockup mechanism which engages and disengages to directly connect and disconnect input and output shafts of a torque converter of the automatic transmission to and from each other. A control system for such a vehicle has a deceleration detecting circuit which detects that the engine is decelerating based on the engine speed and a throttle opening, and a lockup mechanism control circuit which causes the lockup mechanism to engage when the engine is decelerating and permits the same to disengage when the deceleration of the engine finishes. The control system inhibits the lockup mechanism control circuit from causing the lockup mechanism to disengage in a period in which the engine speed can temporarily fall because of the automatic transmission's shifting into neutral in the process of a downshift.