Mazda Motor Corporation

Yuki Tsuchitori

Manabu Sasahara

Tatsuhiko Iwasaki

Tadashi Saito

Tomotaka Ishizaka

Koshiro Saji

Shigeru Nagayama

Makoto Yamada

Hiroki Hanae

Shigeyoshi Okunishi

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

A control system of a vehicle includes a driving source configured to generate a driving force of the vehicle and transmit the driving force to driving wheels, without intervention of a torque converter, a transmission provided between the driving source and the driving wheels, a friction engagement element used for starting the vehicle, the friction engagement element being provided between the driving source and the driving wheels so as to be engageable and disengageable, and a controller configured to control an engaging force of the friction engagement element to adjust the driving force transmitted from the driving source to the driving wheels. The controller sets a target acceleration of the vehicle based on a rotational speed difference between an input rotational speed and an output rotational speed of the transmission, and controls the engaging force based on the target acceleration.

Vehicle control system

A control system of a vehicle includes an automatic transmission provided with a plurality of friction engagement elements changeable between engaged and disengaged states, and configured to form a plurality of gear stages by changing a combination of three friction engagement elements to be selectively engaged among the friction engagement elements, and a controller which controls the change between the engaged and disengaged states of each friction engagement element. The controller performs a neutral control in which, for setting the automatic transmission to a neutral state in which a driving force of a drive source is not transmitted to driving wheels, while two of the three friction engagement elements engaged when forming each gear stage are kept engaged, the remaining one of the three friction engagement element is disengaged. The two friction engagement elements engaged during the neutral control are common in at least two adjacent gear stages.

Provided is a frictional engagement element including: a plurality of friction plates; a piston movable between a releasing position and an engaging position; and a first urging mechanism and a second urging mechanism configured to urge the piston in an engaging direction from the releasing position toward the engaging position. Urging forces of both of the first urging mechanism and the second urging mechanism act on the piston from the releasing position to a first position in the engaging direction. The urging force of the first urging mechanism acts on the piston from the first position to a second position closer to the engaging position than the first position. The first position is a predetermined position where the piston does not abut against the friction plates, and the second position is a position where the piston abuts against the friction plates and the clearances are reduced.

Frictional engagement element and automatic transmission

Provided is an automatic transmission including: an input section to which power generated by a drive source is input; an output section configured to output a drive force; and a gear shifting mechanism configured to change a gear ratio. The power is input to the input section without intervention of a hydraulic power transmission device. The gear shifting mechanism includes a predetermined frictional engagement element for achieving a starting gear ratio of a vehicle. The frictional engagement element includes: a plurality of friction plates arranged with clearances therebetween; a piston movable between a releasing position where the friction plates are brought into a released state, and an engaging position where the friction plates are brought into an engaged state by pressing the friction plates; and an urging mechanism configured to urge the piston so that the piston abuts against the friction plates and the clearances are reduced.

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Hiroshima, Japan

Yuki Tsuchitori