Jatco Corporation

Hideki Oshita

Hiroyasu Tanaka

Takuichiro Inoue

Kousuke Abe

Masahiro Yamamoto

Youhei Ishikawa

Shigeki Shimanaka

Tatsuo Wakahara

Tatsuo Ochiai

Tatsuya Hayashi

Yoshihisa Kodama

Yukiyoshi Inuta

Morimasa Yamawaki

Kazuo Tomioka

Aki Hayakawa

Masayuki Mannen

Shouji Watanabe

When an inertia phase of an upshift of the transmission is started during a lockup clutch engagement operation, a following command oil pressure to be used during a following lockup clutch engagement operation is learned on the basis of a slip rotation speed, which is a rotation speed difference between an input side rotation speed of the torque converter and an output side rotation speed of the torque converter, at or after a start point of the inertia phase.

Automatic transmission and learning method thereof

When gear ratio is abnormally increased due to failure of a secondary pulley rotation sensor or slip in a V belt, demand torque of an engine is rapidly reduced, and after upper limit regulation of a target secondary pulley pressure is performed for a second predetermined time, control of the target secondary pulley pressure according to an output torque of the engine is performed. Thereby, since an actual torque of the engine does not exceed a belt capacity capable of holding a belt by a secondary pulley pressure which is actually generated, when the secondary pulley rotation sensor fails, no slip occurs in the V belt.

Hydraulic control system of belt-type continuously variable transmission for vehicle

The shift control apparatus for a continuously-variable transmission includes a primary pulley; a secondary pulley connected with the primary pulley by a belt; a shift actuator that varies a speed ratio; a line pressure adjusting that adjusts a line pressure; a secondary-pressure adjusting section that adjusts a secondary pressure; and a control section that controls the shift actuator, the line pressure adjusting section, and the secondary-pressure adjusting section. Moreover, the control section includes a fail determining section that determines whether the shift actuator is under a failed condition. The control section carries out a fail-safe shift-actuator fixing control to fix the shift actuator, when the fail determining section determines that the shift actuator is under the failed condition, and carries out a fail-safe hydraulic control to bring the line pressure to its upper limit pressure and bring the secondary pressure to its maximum pressure, when a control-start criterion predetermined to secure driving performance of the vehicle is satisfied under the failed condition.

Shift control apparatus and method for continuously variable transmission

A controller () controls the supply of oil pressure to a primary pulley () and a secondary pulley () of a belt-drive continuously variable transmission () in accordance with the depression amount of an accelerator pedal () of a vehicle. When slippage is detected in a V-belt () that is wrapped around the primary pulley () and secondary pulley (), the controller () reduces the output torque of an engine () of the vehicle to stop the V-belt () from slipping. Meanwhile, damage to the V-belt () caused by slippage is prevented by reducing the oil pressure supply to the secondary pulley ().

Control of belt-drive continuously variable transmission

An input torque control system is provided with a primary pulley, a secondary pulley, a V belt wound between these pulleys, a step motor to change a pressure difference between the primary pulley pressure and the secondary pulley pressure to change a gear ratio of the transmission, a memory unit to store pulley information immediately before a vehicle stop, and a torque restricting section. When an initialization operation of the step motor is started without pulley information stored in the memory unit, an output torque of the engine is restricted, and the restriction is removed after the initialization operation is finished.

Input torque control system of belt-type continuously variable transmission for vehicle

During a downshift of a belt-drive continuously variable transmission, occurring owing to vehicle deceleration, a CVT controller foretells that a slippage between a drive belt and each of primary and secondary variable-width pulleys tends to occur, when a primary pulley pressure is less than a first predetermined pressure level and a primary pulley speed is less than a first predetermined rotational speed. When the belt slippage has been foretold, the CVT controller inhibits the primary pulley pressure from dropping by setting an actual transmission ratio calculated before a set time period from a time when the slippage has been foretold or a transmission ratio of a relatively higher speed side as compared with a ratio-change operating state obtained when the slippage has been foretold, to a desired transmission ratio, or by relatively rising a line pressure as compared with a line pressure level produced when the slippage has been foretold.

Slippage prevention apparatus of belt-drive continuously variable transmission for automotive vehicle

A transmission controller commands a demand torque of an engine to an engine controller according to an actual secondary pulley pressure that is detected by a secondary pulley pressure sensor when a vehicle speed is 0 km/h and a state wherein gear ratio is equal to or higher than a predetermined gear ratio is continued for a first predetermined time or more. Thereby, since an input torque corresponding to a secondary pulley pressure which is actually generated is inputted to a primary pulley even when a failure occurs in the secondary pulley rotation sensor, engine performance of a vehicle can be ensured.

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Fuji, Japan

Hideki Oshita