Mazda Motor Corporation

Shigeru Nagayama

Shinya Kamada

Shin Nakano

Kenji Sawa

Tatsutoshi Mizobe

Minoru Kuriyama

Toshihisa Marusue

Takayuki Sumimoto

Takuji Fujiwara

Mitsutoshi Abe

Manabu Sasahara

Fumiaki Baba

Kozo Ishii

Kazuo Takemoto

Hidehiko Mishima

Hiroaki Yokota

Kazunori Enokido

Makoto Yamada

Yuki Tsuchitori

Hiroyuki Matsumoto

Koichiro Takeuchi

Osamu Watanabe

Yuji Nakahara

Masato Ohtani

An automatic transmission control system includes an automatic transmission provided with a first friction engagement element including friction plates, a piston movable between engaged and disengaged positions for engaging and disengaging, respectively, the friction plates, and engaging and disengaging hydraulic pressure chambers applying engaging and disengaging hydraulic pressure for setting the piston at the engaged and disengaged positions, respectively, first and second hydraulic pressure control valves which adjust the engaging and disengaging hydraulic pressure, respectively, and a controller which controls the first and second hydraulic pressure control valves. When disengaging the engaged first friction engagement element, the controller performs a first control to the first hydraulic pressure control valve to raise the engaging hydraulic pressure, a second control to the second hydraulic pressure control valve to then raise the disengaging hydraulic pressure, and a third control to the first hydraulic pressure control valve to then reduce the engaging hydraulic pressure.

Control system of vehicle including automatic transmission

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.

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.

Adaptive pressure control based on difference between target and actual

A multiple stage automatic transmission includes a main transmission mechanism, a sub-transmission mechanism connected with the main transmission mechanism to for introduction of a torque therefrom, and a frictional element connected with the sub-transmission. The engaging force of the frictional element is changed at least by two steps in accordance with a shift mode without changing a hydraulic pressure applied for actuating the frictional element. A shift shock, therefore, can be obviated.

Multiple stage automatic transmission

An automatic transmission has a hydraulic circuit which controls supply of engaging pressures to friction coupling elements. The hydraulic circuit has a first hydraulic passage having a hydraulic pressure control valve including an accumulator, a second hydraulic passage which is provided in parallel to the first hydraulic passage and is provided with an electrically controlled hydraulic pressure control valve, and a shift valve which selectively connects a predetermined friction coupling element to the first hydraulic passage or the second hydraulic passage.

Automatic transmission control system

A control system for a torque converter includes a lock-up clutch provided in the torque converter for connecting input and output members of the torque converter directly, and a shift valve having first and second spools disposed in series in a sleeve for shifting an introduction of an engaging and releasing pressure acting on the lock-up clutch in accordance with positions of the first and second spools. The first spool is subjected to a first hydraulic pressure at one end thereof. The second spool is subjected to a second hydraulic pressure at one end thereof opposite to the one end of the first spool. The first and second spools are subjected to a third hydraulic pressure therebetween. The control system further has a first control device for controlling the first hydraulic pressure, and an adjusting valve for controlling the releasing pressure of the lock-up clutch. The shift valve provides the first and second spools with first, second and third positions corresponding to a converter condition, lock-up condition and slip condition, respectively. The shift valve is shifted between the second and third positions when the releasing pressure is relatively low so that the releasing pressure is continuously changed irrespective of the shifting action among the first, second and third positions of the shift valve. An abrupt change in the engaging force of the lock-up clutch is prevented.

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Hiroshima, Japan

Shigeru Nagayama