Mazda Motor Corporation

Takeyoshi Kawa

Tomoo Sawazaki

Hiroshi Shinozuka

Shinya Kamada

Tatsuhiko Iwasaki

Koichi Yamamoto

Takamichi Teraoka

Yasunori Kanda

Akinobu Aoki

Naotaka Hirami

Masakazu Hombo

Kazushi Kurokawa

Kenji Sawa

Junichi Doi

An automatic transmission control system having a hydraulic control circuit for supplying operating pressure selectively to a plurality of friction coupling elements to place the transmission in desired gears includes a pressure generator for generating operating pressure and supplying it to specific coupling elements which operate in response to operating pressure at different highest levels and an accumulator having a spring loaded piston which provides an increase in operating pressure at a rate variable according to movement of the piston, the rate being greater for greater piston movement as compared with for smaller piston movement, the accumulator being brought into communication selectively with the specific coupling elements by means of a switching element.

Hydraulic control system for automatic transmission

A control system for an automatic transmission having at least a friction coupling element which is coupled with a hydraulic pressure increasing by way of a leveled transitional pressure has an accumulator which discharge a high level of pressure accumulated therein into the friction coupling element during a gear shift under the condition where the line pressure is low.

Control system for automatic transmission

A control system for an automatic transmission having friction coupling elements, at least one of which is locked in 3rd and 4th gears and unlocked in 1st and 2nd gears, includes a first shift valve shiftable between 3rd and 4th gears, and second shift valve shiftable between in 2nd gear and 1st gear in which engine brake available, and a solenoid valve providing control pressure which is selectively directed to these shift valves and cause them to shift so as to lock or unlock the friction coupling elements.

Automatic transmission control system

A control system for an automatic transmission having a transmission gear mechanism and a plurality of friction coupling elements which are selectively locked and unlocked with hydraulic oil to change power transmission paths to place the automatic transmission into desired available gears, a first one of the friction coupling elements having a locking pressure chamber and an unlocking pressure chamber and being locked when operating oil is supplied into only the locking pressure chamber and unlocking when operating oil is coincidentally supplied into the locking pressure chamber and the unlocking pressure chamber, and a second one of the friction coupling elements having a locking/unlocking pressure chamber in communication, with the unlocking pressure chamber of the first friction coupling element and being locked only when operation oil is supplied into the locking/unlocking pressure chamber. The control system includes a transition level control for controlling a pressure level of transitional pressure of operating oil increasing in pressure level while being supplied to the locking/unlocking pressure chamber of the second friction coupling element during a first specified gear shift with a first friction coupling element and the second friction coupling element are simultaneously unlocked and locked, respectively, and decreasing while being discharged from the locking/unlocking pressure chamber of the second friction coupling element during a second specific gear shift wherein the first friction coupling element and the second friction coupling element are simultaneously locked and unlocked, respectively, and a transitional duration control for controlling a duration time of the transitional pressure during any one of the first and second specific gear shifts.

A hydraulic control system for an automatic transmission having at least a forward clutch which is unlocked in a fourth gear and locked in other forward gears and a lock-up clutch for coupling input and output elements of a torque converter together is equipped with a pressure control valve for controlling operating pressure for the forward clutch, a lock-up control valve for connecting and disconnecting the first valve from the lock-up clutch, a pressure line through which control source pressure is introduced into the forward clutch while the first valve is in communication with the lock-up clutch, and a shift valve for discharging the control source pressure from the pressure line.

Forward clutch and lockup clutch control in an automatic transmission

A control system for an automatic transmission having at least a friction coupling element which is coupled with a hydraulic pressure increasing by way of a leveled transitional pressure has an accumulator which discharge a high level of pressure accumulated therein into the fiction coupling element during a gear shift under the condition where the line pressure is low.

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Hiroshima, Japan

Takeyoshi Kawa