Abstract: A system for controlling an automatic transmission of a vehicle, wherein the initial value of the desired pressure to be supplied to a hydraulic clutch for the current gear now being engaged is determined appropriately, when conducting a power-on downshifting, so as to decrease the shift shock experienced by the vehicle occupant effectively, irrespectively of the change in he throttle opening, while ensuring to reduce the volume of the mapped data.

Abstract: A system for controlling an automatic transmission of a vehicle, wherein a pressure to be supplied to the hydraulic clutch of a target gear is determined based on a desired value of acceleration of gravity acting in the longitudinal direction of the vehicle and other parameters including an engine torque, thereby decreasing the shift shock effectively, while ensuring to finish the shift within an expected period of time. Moreover, the engine torque is estimated using a parameter indicative of inertia torque used for raising the engine speed. With this, it becomes possible to determine the engine torque inputted to the transmission, thereby decreasing the shift shock more effectively.

Abstract: A down-shift control system is provided, by which if sufficient torque cannot be obtained for an acceleration request or intention at a shift position, a down-shift operation is suitably performed so as to realize a reliable driving capability and no shift-busy phenomenon occurs.

Abstract: A throttle controller is provided so as to reduce a load imposed on the drive and transmission system in the stall state in which both the accelerator and brake are depressed.

Abstract: The lock-up clutch control apparatus is provided with reference values for operating variations of the accelerator pedal predetermined for respective gear positions. The lock-up clutch control apparatus comprises a tightening permission judgement device 25 for judging whether it is appropriate to permit or prohibit tightening of the lock-up clutch, based on comparison between a reference value and an operating variation at present car conditions. Thereby, the lock-up clutch control apparatus is capable of reflecting the driver's intention to accelerate or reduce the car speed and is capable of enhancing drivability as well.

Abstract: A lock-up control device controls an engaging force of a lock-up clutch, which shares engine output with a torque converter to transmit it toward an input shaft of a transmission of a car. First, target driving force is produced based on accelerator pedal opening and car velocity. Then, required torque is produced based on a gear ratio and the target driving force. Target engine speed is produced based on the required torque, wherein the target engine speed is set to avoid occurrence of abnormal sounds and abnormal vibrations. Thus, the lock-up clutch is controlled in such a way that real engine speed does not become less than the target engine speed in case of a gear change corresponding to a shift-up operation, for example. Basically, the lock-up clutch is controlled to have engaging force, which is made as maximal as possible to improve fuel efficiency. In other words, the lock-up clutch is controlled to be as tightly as possible.

Abstract: A lock-up control device is provided to control engaging force of a lock-up clutch, which shares engine output with a torque converter to transmit it toward an input shaft of a transmission. Herein, input shaft torque is estimated based on engine speed and engine intake negative pressure, while engine torque is estimated based on engine speed and throttle opening. A weight coefficient is produced based on an amount of variations of the engine torque when the amount of variations is greater than a prescribed value. Then, weighted mean engine torque is calculated by the input shaft torque and engine torque in accordance with the weight coefficient. Thus, the lock-up control device controls the lock-up clutch based on the weighted mean engine torque in such a way that the engaging force of the lock-up clutch is increased in response to the rise timing of the weighted mean engine torque.