Patent Number: 6,254,508

Title: 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 B4 rises and the release-side hydraulic pressure B5 drops, the rotational speed N.sub.T of the input shaft changes from a second speed state toward a third speed state and the engine torque T.sub.E 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 .omega. 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.

Inventors: Kojima; Kouichi (Anjo, JP), Tsutsui; Hiroshi (Anjo, JP), Saitou; Masao (Anjo, JP), Nishida; Masaaki (Anjo, JP), Yamamoto; Yoshihisa (Anjo, JP)

Assignee: Aisin AW Co., Ltd.

International Classification: F16H 61/06 (20060101); F16H 61/04 (20060101); F16H 59/68 (20060101); B60K 041/04 ()

Expiration Date: 07/03/2018