Engine torque control during multiple speed changes of an automatic transmission

Abstract

In a multiple speed-change operation for switching between an up-shift operation and a down-shift operation, engine torque control is adapted to an actual change in speed-change state, whereby an abrupt change in rotational speed of the input shaft is prevented. One embodiment relates to a speed-change operation from the second speed to the third speed, wherein the engagement-side hydraulic pressure B,rises and the release-side hydraulic pressure B,drops, the rotational speed N,of the input shaft changes from a second speed state toward a third speed state and the engine torque T,is reduced by a predetermined amount TCU. If a command to perform a speed-change operation from the third speed to the second speed is issued during the aforementioned speed-change operation from the second speed to the third speed, control of the hydraulic pressures is switched to the speed-change operation from the third speed to the second speed. If it is detected because of the hydraulic pressure control that the direction of the change &ohgr; in rotational speed of the input shaft has changed toward the second speed, it is determined that the speed-change operation has actually started. Then, the torque reduction operation is suspended, and the torque is gradually restored.