Abstract: A power train control system includes an automatic transmission shift control which detects an operational failure of an electric throttle valve based on an electric throttle opening. The transmission shift control governs or controls shifting of the automatic transmission, based on an electric throttle opening and a vehicle speed when no operational failure of the electric throttle valve is detected and based on a composite opening of an electric throttle opening and a mechanical throttle opening and a vehicle speed when operational failure of the electric throttle valve is detected.

Abstract: An automatic transmission shift control system includes a hydraulically controlled valve mechanism for connecting and disconnecting a supply of hydraulic pressure to frictional coupling elements. Connection and disconnection of the hydraulic pressure supply locks and unlocks the frictional coupling elements in order to automatically shift an automatic transmission into desired gears. A time regulator regulates a duration time for which the valve mechanism is kept actuated and with which a speed at which the frictional coupling element is locked changes. The time regulator is controlled so as to variably regulate the duration time according to conversion efficiency of a torque converter. This conversion efficiency is, for example, determined from a speed conversion ratio and a torque conversion ratio.

Abstract: A control system for an automatic transmission including a main transmission and a subtransmission whose shift operation is carried out by hydraulically. The control system comprises a first device for adjusting a gear ratio advance of the main transmission, the gear ratio advance corresponding to a gear ratio change during the shift operation, a second device for adjusting a gear ratio advance of the subtransmission, the gear ratio advance corresponding to a gear ratio change during the shift operation, and a device for controlling the frist adjusting device and the second adjusting device during concurrent shift operations of the main transmission and the subtransmission so that the gear ratio advances of the main transmission and the subtransmission become equal to respective predetermined target gear ratio advances.

Abstract: An automatic transmission containing a multi-stage shift mechanism composed of a planetary gear mechanism is arranged to change the output of the combustion engine in synchronization with its shift operation. The planetary gear mechanism is connected to the output shaft of the combustion engine through the torque converter and is so arranged as to assume four forward speed stages by coupling or uncoupling plural friction coupling elements such as clutches, etc. The number of revolutions of input of the planetary gear mechanism is detected through a sensor by detecting the number of revolutions of the turbine, and the number of revolutions of its output is likewise detected by a sensor.

Abstract: A control system for a vehicle engine coupled with an automatic transmission, which comprises a detecting portion for detecting a condition of speed change operation in the automatic transmission, a speed sensor for detecting engine speed or turbine speed in the automatic transmission, a first period determining portion for determing a first period of time, in which the speed change operation is to be carried out, by calculation based on the speed detected by the speed sensor, a second period determining portion for determining a second period of time, in which the speed change operation is to be carried out, in accordance with a predetermined lapse of time after the condition of the speed change operation is selected, and a torque control portion operative to vary torque produced by the vehicle engine to suppress torque shock resulting from the speed change operation during the first period of time when a condition of shifting-up operation is detected by the detecting portion and to vary the torque so as to

Abstract: A device provides transmission control whereby when a vehicle starts from standing state, even if a driver releases a brake pedal, action of the brake is maintained compulsorily until the starting gear position is formed by connection of frictional elements in the automatic transmission. Therefore, this device prevents effectively a vehicle from slipping down, upon starting on an upwardly sloped road, without more action of the brake than is necessary and with good startability.

Abstract: A control system for a power train provided in a vehicle to include an engine which has an engine output adjusting device, such as a throttle valve, controlled through an electric actuator in accordance with a controlled variable on an accelerator and an automatic transmission in which a speed change operation is automatically performed utilizing operating oil pressure produced in an oil hydraulic control circuit for actuating a speed change mechanism in the automatic transmission having engaging friction elements and controlled to vary in accordance with an operating condition of the engine, which comprises a first detecting device for detecting the controlled variable on the accelerator, a second detecting device for detecting a controlled variable on the engine output adjusting device, a third detecting device for detecting a travelling speed of the vehicle, a device for controlling the speed change mechanism to cause the same to carry out the speed change operation based on detection outputs of the first

Abstract: A torque converter slip control device used in an automatic transmission of an internal combustion engine of a vehicle has a torque converter to transfer engine torque to an input shaft of the automatic transmission. A feed-forward slip control subroutine controls a hydraulic circuit in a feed-forward control to vary the coupling efficiency of a lockup clutch to cause the torque converter to allow slippage at a rate suitable for cancelling a fluctuation of engine torque when the internal combustion engine is at rotational speeds higher than a preselected rotational speed higher than a predetermined fuel injection recovery speed at which an injection of fuel by a fuel system is recovered during the detection of the deceleration state of the vehicle by a deceleration senser.

Abstract: A control system for a vehicle engine coupled with an automatic transmission, which comprises a torque controller operative to vary torque produced by the vehicle engine, in accordance with a controlled variable, so as to suppress torque shock resulting from a speed change operation carried out to vary a gear ratio in a power transmitting gear arrangement provided in the automatic transmission, an operation detector for detecting the speed change operation, a controlled variable setting device for determining the controlled variable in accordance with an operating condition of the vehicle engine and the speed change operation, and a controlled variable revising device for varying the controlled variable so as to reduce variation in the torque brought about by the torque controller under a condition in which the speed change operation causing a change from one to another of speed ranges of relatively small gear ratios is detected by the operation detector, as compared with variation in the torque brought about

Abstract: A hydraulic control system for an automatic transmission including a pressure regulating valve responsive to a pilot pressure to produce a regulated line pressure which is applied through a switching valve to an actuator of a clutch. The switching valve is also responsive to the pilot pressure to allow the pilot pressure to be introduced to the actuator when the pilot pressure is below the predetermined value and passes the line pressure to the actuator when the pilot pressure is above the predetermined value.