Abstract: A control system of an automatic transmission includes a torque converter, a lock-up clutch for directly connecting input and output members of the torque converter, a pressure control valve which changes a hydraulic pressure to control an engaging force of the lock-up clutch, and a pressure regulator, disposed in an engaging passage, which supplies hydraulic pressure to engage a frictional element. The pressure regulator adjusts a primary pressure and produces an output hydraulic pressure corresponding to a control pressure introduced into a control port of the pressure regulator. A control pressure supply device is provided for introducing the control pressure, controlled by the pressure control valve, into the control port of the pressure regulator. The number of parts can be reduced without producing any inconvenience.

Abstract: An automatic transmission control system for selectively locking and unlocking a plurality of frictional coupling elements is provided within an automatic transmission so as to place the automatic transmission into one of various possible gears. The control locks a specific one of the frictional coupling elements with locking pressure when the automatic transmission performs a specific gear shift and unlocks it by reducing the locking pressure when causing it to perform, an opposite gear shift reverse to the specific gear shift. The locking pressure is increased by way of a relatively high level of shelf pressure during the specific gear shift and reduced by way of a relatively low level of shelf pressure during the opposite gear shift.

Abstract: A shift control system of an automatic transmission includes a first element which is to be released in a shift operation, a second element which is to be engaged in the shift operation, and a target shift time set section for setting a target time period of the shift operation needed for releasing the first frictional element and engaging the second frictional element. A shift time calculation section is provided for obtaining an actual time period of the shift operation needed for releasing the first frictional element and engaging the second frictional element, and a releasing pressure control section is provided for receiving output of the target shift time set section and the shift time calculation section for controlling a releasing pressure of the first frictional element in the shift operation based on the difference between the target and actual time periods of the shift operation.

Abstract: A control system for supercharging an internal combustion engine equipped with an automatic transmission includes superchargers which provide a variable capacity controlled by a supercharging capacity controller according to a supercharging capacity control pattern. The supercharging capacity is controlled so as increase at engine speeds higher when a demand to shift the automatic transmission to a lower speed gear is present than when a demand to shift the automatic transmission to a higher speed gear is present. Change of supercharging capacity is suspended for a predetermined period of time when a demand to shift the automatic transmission is present.

Abstract: A control system for supercharging an internal combustion engine equipped with an automatic transmission includes a capacity changeable supercharger. The supercharger is controlled by a supercharging capacity controller, having data representative of at least one supercharging capacity control line, so that its supercharging capacity is charged according to operating conditions of the internal combustion engine. A transmission shift controller, causing the automatic transmission to shift according to operating conditions of the internal combustion engine, has data representative of at least one gear shift control line for a shift operation of the automatic transmission. The at least one gear shift control line has an intermediate portion, including an intersection with the supercharging capacity control line defined by a specific engine load between upper and lower middle vehicle speeds.

Abstract: According to the lockup device of a fluid transmission under the present invention, at the decelerating running when the change rate of engine load exceeds a set value, a lockup control pattern is changed so that the area where the lockup device is controlled to perfect friction or to the specified friction force. By this change, at the decelerating running large engine brake force can be worked and a good feeling of deceleration can be given to a driver. In the case where fuel supply to the engine is suspended at the decelerating running of the engine, transmission of large engine brake force as mentioned above results in comparatively longer time of maintaining high engine speed and longer time of fuel supply cutting off, with consequent saving of fuel consumption. Moreover, by changing the target slip quantity to the increasing side at the accelerating running, torque increasing action at the accelerating running is displayed effectively and accelerability can be improved.

Abstract: An automatic transmission including a torque converter and a multiple stage transmission gear mechanism. A hydraulically actuated brake and a hydraulically actuated clutch is provided for alternate engagement to select alternately one of two adjacent gear stages. In order to prevent gear shift shock, the engaging of the clutch or the brake is controlled so that the engaging rate is faster for a predetermined time period in an initial period of a gear shifting operation than in a remainder period. A control circuit is provided to monitor the gear shifting operation and modifying the predetermined time period in accordance with the results of the latest gear shifting operation and store the modified value for the use in a next gear shifting operation.