Mazda Motor Corporation

Shin Nakano

Shinya Kamada

Kenji Sawa

Shigeru Nagayama

Yasunari Nakayama

Toshihisa Marusue

Mitsutoshi Abe

Hiroaki Yokota

Hiroyuki Matsumoto

Mitsuo Yasuno

Mitsukazu Tasaka

Yuji Nakahara

An automatic transmission control system for an automotive automatic transmission including a speed sensor for detecting a vehicle speed of the vehicle, a load sensor for detecting a load acting on the driving torque generator, a torque sensor for detecting input torque transmitted to the automatic transmission from the driving torque generator, first working fluid pressure control communicating both a first friction coupling element's unlocking pressure chamber and a second friction coupling element's pressure chamber with the working fluid source in the hydraulic pressure control system for controlling supply of working fluid pressure to and from both the unlocking pressure chambers and a second working fluid pressure control in the fluid path communicating both the first friction coupling element's locking pressure chamber with the working fluid source for controlling supply of working fluid pressure to and from the first friction coupling element's locking pressure chamber. Thereby controlling the second working fluid pressure control such that, until a start of a substantial gear shift period of time from an appearance of the specific gear shift command signal, the level of the working fluid pressure supplied to the locking pressure chamber of the first friction coupling element being directly related to a level of the working fluid pressure supplied to the locking pressure chamber of the first friction coupling element during the substantial gear shift period of time.

Automatic transmission control system for automobiles

An automatic transmission control system for an automatic transmission including a hydraulic pressure control circuit which supplies locking and unlocking pressures selectively to a plurality of friction coupling elements to lock and unlock the selected friction coupling elements, changing a torque transmission path in a transmission gear mechanism to provide available gears, a specific one of which is achieved by locking and unlocking simultaneously specific friction coupling elements.

A torque responsive hydraulic control system for an automatic transmission with a plurality of hydraulically actuated friction control elements. A working hydraulic pressure in the elements is controlled during shifting such that a pressure in a first element is removed after a specific state of the element is achieved. The removal being responsive to the torque of an input shaft of the transmission, the expiration of a specific time period, or a position of the throttle valve of a driving engine.

An automatic transmission control system, which includes a 2-4 brake having a servo apply fluid chamber and a servo release fluid chamber and a 3-4 clutch having a fluid chamber and causes a 3-2 shift by engaging the 2-4 brake and disengaging the 3-4 clutch, controls engaging pressure for the 3-4 clutch by way of controlling servo apply pressure for the 2-4 brake to disengage the 3-4 brake so as thereby to increase turbine speed during the 3-2 gear shift and, at near the end of the 3-2 gear shift, brings the 2-4 brake into engagement. During control of disengagement of the 3-4 clutch, the pressure difference between servo apply pressure and servo release pressure is changed to become greater at the beginning of the gear shift.

A shift control system of an automatic transmission includes a first element which is to be released in a shift operation, a second element which is to be engaged in the shift operation, and a target shift time set section for setting a target time period of the shift operation needed for releasing the first frictional element and engaging the second frictional element. A shift time calculation section is provided for obtaining an actual time period of the shift operation needed for releasing the first frictional element and engaging the second frictional element, and a releasing pressure control section is provided for receiving output of the target shift time set section and the shift time calculation section for controlling a releasing pressure of the first frictional element in the shift operation based on the difference between the target and actual time periods of the shift operation. An engaging pressure control section is used for controlling an engaging pressure of the second frictional element in the shift operation. A shift shock is effectively suppressed by the shift control system.

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Hiroshima, Japan

Shin Nakano