Mitsubishi Jidosha Kogyo Kabushiki Kaisha

Takahiro Taki

Yoichi Furuichi

Shoji Kan

Takeshi Kitagawa

Hiroshi Takuma

Kenji Suzuki

Toshinori Ishii

Yuzo Yano

Shift control apparatus for automatic transmission for vehicle

Hydraulic pressure supplied to the frictional engaging element of an automotive transmission is corrected to a higher value in the event that the engine is started after a long standstill condition and the first speed ratio is selected, thereby reducing speed-shift shocks when the engine is started from a standstill condition and the first speed ratio is selected.

A direct-coupling control method capable of improving fuel efficiency by performing slip direct-coupling control of a torque converter, in which a driving force transmission of an automatic transmission is operated under an approximate direct-coupling condition that permits slight slippage of the torque converter, in a predetermined operating range of the automatic transmission such as a low speed range thereof, and capable of positively detecting and preventing direct-coupling vibration caused by deterioration of hydraulic oil or the like. In the slip direct-coupling control, an occurrence of direct-coupling vibration is detected when a variation of a slip amount changing beyond predetermined upper and lower limit values is found a predetermined number of times during a predetermined period of time, or when a variation in the rotational rate of the output shaft of the torque converter still continues even after the slip direct-coupling control is interrupted for the reason that the rotational rate has varied beyond a permissible range. Upon detection of the direct-coupling vibration, the slip direct-coupling control is inhibited.

Direct-coupling clutch control method for an automatic transmission

In an automatic transmission for a vehicle having at least one frictional engaging element and an electromagnetic valve to control hydraulic pressure supplied to the frictional engaging element and achieving a plurality of speed ratios including a predetermined speed ratio achieved by engaging the frictional engaging element, a shift control apparatus includes retardation rate detection means for detecting retardation rate of the vehicle and electromagnetic valve control means for controlling the electromagnetic valve according to the value detected by the retardation rate detection means, and hydraulic pressure supplied to the frictional engaging element is corrected by the electromagnetic valve through electromagnetic valve control means according to the retardation rate of the vehicle detected by the retardation rate detection means, thereby reducing speed-shift shocks during a down-shift in association with retardation of the vehicle.

Growing community of inventors

Kyoto, Japan

Takahiro Taki