Abstract: An automatic transmission control system equipped with a shift lever position sensor which includes a plurality of switches which output binary signals following a shifting motion of a gear shift lever. Patterns of combinations of the switch outputs are preselected so as to represent positions to which the gear shift lever is manually shiftable. The switches are broken down into two groups each of which produces a binary code carrying information about the position of the gear shift lever to monitor a failure in operation of the shift lever position sensor. The control system also works to perform a deemed D-position hydraulic transmission control to ensure the running of the vehicle even if the shift lever position sensor is failing.

Abstract: A controller of an automatic transmission having a lockup clutch and a control method of the automatic transmission, in which engine rotational speed is prevented from changing even though turbine rotational speed changes at gear shift and slip control can be carried out without making a driver feel uncomfortable are provided. When a speed change command is detected and it is determined that an inertia phase has not yet started, target engine rotational speed during a replenish period is calculated and the target engine rotational speed control is carried out to have the target engine rotational speed. When it is determined that the control is in the inertia phase, another target engine rotational speed during the inertia phase is calculated. Then, target engine rotational speed control in which the engine rotational speed at the start of the inertia phase is maintained as the target engine rotational speed is carried out.

Abstract: A control apparatus and method for an automatic transmission that prevents incorrect determination of the start of a gear change inertia phase caused by bounding of an input shaft speed, and that prevents delay of the detection of the start of the inertia phase. A working fluid pressure of the frictional element is feedback-controlled in an inertia phase of a gear change transition of a speed-changing gear mechanism, wherein the input shaft speed of the mechanism changes along with an engaging operation of a frictional element of the mechanism. When it is determined that a starting point for the inertia phase control has been reached, inertia phase control is initiated. After a predetermined determination interval subsequently elapses, it is determined whether the inertia phase control should continue.

Abstract: A vehicle automatic transmission control controls fluid pressure changes applied to a frictional engagement element which is being changed from an engaged state to a disengaged state at a stage before input shaft rotational speed starts to increase from the beginning of a down-shift control. The control instruction value is set to gradually decrease the applied fluid pressure and to increase the ratio of such decrease with elapsed time. Specifically, a solenoid is used to control the fluid pressure applied to a clutch. The duty-cycle instruction for the solenoid is determined based on a quadratic function expressed as: duty cycle value=initial value-at.sup.2.

Abstract: A controller of an automatic transmission having a lockup clutch and a control method of the automatic transmission, in which engine rotational speed is prevented from changing even though turbine rotational speed changes at gear shift and slip control can be carried out without making a driver feel uncomfortable are provided. When a speed change command is detected and it is determined that an inertia phase has not yet started, target engine rotational speed during a replenish period is calculated and the target engine rotational speed control is carried out to have the target engine rotational speed. When it is determined that the control is in the inertia phase, another target engine rotational speed during the inertia phase is calculated. Then, target engine rotational speed control in which the engine rotational speed at the start of the inertia phase is maintained as the target engine rotational speed is carried out.

Abstract: An automotive automatic transmission has an input shaft receiving a rotational force from an engine, an output shaft for outputting a rotational force to a vehicle driving wheel, a frictional engagement device having an adjustable engagement condition, and a transmission device for transmitting a rotational force from the input shaft to the output shaft at a gear speed ratio depending on the engagement condition of the frictional engagement device. A control apparatus for the automotive automatic transmission includes an engagement condition adjusting device for adjusting the engagement condition of the frictional engagement device by feeding a hydraulic pressure thereto in response to an instructed control amount.

Abstract: In order to precisely determines the time to start feedback control of line pressure during a shifting period, a shift control computer calculates an effective gear ratio Ge=Nt/Nos at the time of an shift instruction based on input shaft rotational speed Nt and detected vehicle speed Nos and then calculates a parameter F=Nos.times.Ge-Nt indicating the point to start feedback control based on the input shaft rotational speed Nt, the detected vehicle speed Nos and the effective gear ratio Ge. By comparing the calculated parameter F with a predetermined value .DELTA.Nt, hydraulic pressure at the start of shift operation is maintained if F<.DELTA.Nt and, if F.gtoreq..DELTA.Nt, feedback control is performed to cause the input shaft rotational speed Nt to vary in a predetermined manner.

Abstract: A hydraulic control system for an automatic transmission is disclosed which includes a feedback hydraulic control circuit and a hydraulic correcting circuit. The feedback hydraulic control circuit controls the hydraulic pressure supplied to frictional elements of the automatic transmission under feedback control during a shift operation for adjusting the speed of an input shaft or a rate of change in speed of the input shaft of the automatic transmission to agree with a target speed or a target rate. The hydraulic correcting circuit corrects an output of the feedback hydraulic control circuit so as to suppress vibrations of torque transmitted through a drive train of the automatic transmission caused by control of the hydraulic pressure carried out by the feedback hydraulic control circuit within a range of a resonance frequency of the drive train of the automatic transmission.

Abstract: A lock-up clutch control method controls a torque converter comprising an input shaft through which a rotating force from an engine is input, an output shaft which outputs a driving force to the side of driving wheels and a lock-up clutch which operates in response to a hydraulic pressure. A control element controls an engaging pressure of the lock-up clutch by way of the hydraulic pressure. The engaging force of the clutch is controlled in accordance with calculated results of a target following up section for calculating a controlled variable so that a slip follows up a target slip and a control system stabilizing section for calculating the controlled variable so that the disturbance applied to the control system is compensated. Thereby, a stable control may be realized without receiving any effect of the disturbance. The disturbance may be estimated and learned for more accurate control.

Abstract: A position control device includes a fluid-operated directional control valve for controlling the position of the piston of a cylinder assembly under fluid pressure in response to a control signal from an electronic controller. The position of the piston is predicted based on the control signal. A position detector detects when the piston has actually reached a predetermined position. When it is detected that the piston has actually reached the predetermined position, the predicted position of the piston is corrected. The electronic controller applies a control signal to the directional control valve so that the predicted position as corrected will be equalized to a target position for the piston. The predetermined position is a substantially intermediate position of the stroke of the piston. The directional control valve comprises a solenoid-controlled valve for controlling the flow rate of the fluid depending on the magnitude of a current supplied to the solenoid-operated valve.

Abstract: A control apparatus for controlling the twisting amount of a stabilizer provided between left and right wheels of a vehicle in accordance with the vehicle running state. The control apparatus includes a hydraulic cylinder unit coupled between one end portion of the twistable stabilizer and one of the wheels and the cylinder unit has a cylinder body and a piston slidable therein to be expandable and contractable in accordance with movements of the piston. Also included in the apparatus is a hydraulic actuator comprising control valves and coupled to the cylinder unit to control a position of the piston, the position thereof corresponding to the twisting amount of the stabilizer and being detectable by a position sensor.

Abstract: A vehicle has a body, a right-hand wheel, and a left-hand wheel. A first device rotatably connects the right-hand wheel to the body. A second device rotatably connects the left-hand wheel to the body. An elastically deformable stabilizer is connected between the first and second devices. A mechanism serves to positively deform the stabilizer. A sensor may detect an operating condition of the vehicle, such as a steering condition or speed of the vehicle. The stabilizer may be positively deformed in accordance with the detected operating condition of the vehicle.

Abstract: In an automotive vehicle having a stabilizer connected to unspring members, a hydraulic stabilizer control system comprises a hydraulic cylinder unit interposed between the stabilizer and at least one of the unspring members; a road surface sensor for detecting a road surface condition, a speed sensor for detecting a speed of said automotive vehicle, and a steering sensor for detecting a steering angle of said automotive vehicle; and a controlling unit for controlling the hydraulic cylinder unit in accordance with outputs from the sensors. A roll of the vehicle is reduced by this hydraulic stabilizer control system even when the vehicle is turning on a rough road.