Aisin Aw Co., Ltd.

Kouichi Kojima

Hiroshi Tsutsui

Masaaki Nishida

Yutaka Teraoka

Masahiro Hayabuchi

Nobuhiro Iwai

Kiyoshi Akutsu

Masatake Ichikawa

Yoshihisa Yamamoto

Masao Saitou

Masaki Nishide

Hidekazu Funakoshi

A shift control apparatus has first, second, third and fourth engagement elements, and a shift control processing unit engaging the first and the second engagement elements in order to realize a first shift speed, engaging the third and the fourth engagement in order to realize a second shift speed, and inhibiting an increase in torque capacity of one of the first and second engagement elements before starting of release of the second engagement element when shifting from the first to the second shift speed. During shifting from the first to the second shift speed, an increase in torque capacity of one of the first and second engagement elements is inhibited before starting of release of the second engagement element. This prevents a step-like shift shock from being caused by the slowed progression of shifting when release of the second engagement element is started.

Shift control apparatus for an automatic transmission

An automatic transmission achieves a desired shift through an initial stage shift in which a first engagement element is released and a third engagement element is engaged, and a final stage shift in which a second engagement element is released and a fourth engagement element is engaged. A control apparatus sets an estimated rotation acceleration for a transmission input shaft in accordance with an input torque and an input torque rotation acceleration speed, and controls the release of the second engagement element for moving to the final stage shift according to the estimated rotation acceleration. As a result, it is possible to prevent a shifting delay and/or degradation that occurs between the initial stage and the latter stage by continuous transmission of the input rotation (engine rotation) change when moving from the initial stage to the later stage.

Shift control apparatus for automatic transmission

The invention has been made to eliminate a feeling of two-phase speed-change operations by causing a speed-change operation to proceed continuously when the speed-change operation is performed through two-phase control of engagement and release of four engagement elements. To accomplish this purpose, the invention provides a control apparatus for an automatic transmission wherein a predetermined speed-change operation is achieved through a pre-phase speed-change operation in which a first engagement element and a third engagement element are released and engaged respectively and through a post-phase speed-change operation in which a second engagement element and a fourth engagement element are released and engaged respectively. The control apparatus sets a target rotational acceleration of an input shaft of the transmission, and controls release of the second engagement element for a transition to the post-phase speed-change operation in accordance with the target rotational acceleration. Thus, the input speed during the transition from the pre-phase speed-change operation to the post-phase speed-change operation changes continuously, so that bluntness is prevented from being caused between the pre-stage and post-stage speed-change operations.

Speed-change control apparatus for automatic transmission

A lock-up control apparatus for an automatic transmission in which operations of four engagement elements are required when shifting is performed from a first shift speed to a second shift speed, the first shift speed being achieved by engagement of a first engagement element and a second engagement element, the second shift speed being achieved by engagement of a third engagement element and a fourth engagement element. The lock-up control apparatus includes a lock-up control unit that performs a control for bringing a lock-up clutch into one of a disengagement state and a slip state at a start of shifting, and that prevents reengagement of the lock-up clutch at a completion of engagement of the third engagement element when shifting is performed from the first shift speed to the second shift speed during lock up.

Lock-up control apparatus for automatic transmission

The invention eliminates the feeling of two-phase speed-change operations by causing a speed-change operation to proceed continuously when the speed-change operation is performed through two-phase control of engagement and release of four engagement elements. An automatic transmission is such that a predetermined speed-change operation is achieved through a pre-phase speed-change operation in which a first engagement element and a third engagement element are released and engaged respectively and through a post-phase speed-change operation in which a second engagement element and a fourth engagement element are released and engaged respectively. A control apparatus has a torque control capability for adjusting an input torque of a transmission during the pre-phase speed-change control, and ensures continuous changes in the input speed during the pre-phase and post-phase speed-change operations through adjustment of the input torque (torque reduction) to prevent bluntness from being caused between the pre-phase and post-phase speed-change operations.

Control apparatus for automatic transmission

At the time of the 6&rarr;3 speed shift, an automatic transmission achieves a 6&rarr;4&rarr;3 speed shift by controlling the servo pressures of four engageable elements. A control apparatus controls the servo pressure of one engageable element in accordance with the servo pressures of other engageable elements. The engagement and release timings are adjusted by determining and controlling the oil pressures of the hydraulic servos, taking into consideration the 6&rarr;4 shift state (torque sharing) during a shift transitional period. Therefore, engine blow and prolongation are prevented during the 6&rarr;3 shift control.

Speed shift control apparatus of automatic transmission

A shift control apparatus that advances activation of an engagement element to be engaged during a shift requiring engagement and release of four engagement elements, thereby reducing the shift time. The automatic transmission achieves a sixth-to-fourth-to-third shift by controlling servo pressures for the four engagement elements. The control apparatus starts, during the time of the sixth-to-third shift, supply of the hydraulic pressure for activating the engagement element to be engaged at the time of the fourth-to-third shift, thereby advancing the establishment of the engagement stand-by state at the time of the fourth-to-third shift. Accordingly, the reduction in the servo pressure of the engagement element to be released at the time of the fourth-to-third shift can be advanced, thereby reducing the time for the sixth-to-third shift.

Quick shifting is achieved while preventing a shift shock when shifting is caused by grip change of four engagement elements. The automatic transmission requires activation of the four engagement elements when shifting from a first shifting position (sixth speed) to a second shifting position (third speed) is performed. This shifting control apparatus includes shift control means for starting disengagement of a second engagement element after starting disengagement of a first engagement element; completing engagement of a fourth engagement element after completing engagement of a third engagement element; and starting disengagement of the second engagement element before completing engagement of the third engagement element.

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.

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Anjo, Japan

Kouichi Kojima