Abstract: An idling engine clutch release control device of an automatic transmission, which includes an electric switch connected to the accelerator pedal and to an element for metering the fuel, wherein closing of the switch prevents release of the stationary clutch. The switch is controlled by two opposed springs, which close the switch when the pressing force of the driver on the accelerator pedal is significant.

Abstract: Automatic transmission control device with stepped gears comprising a torque converter (1) equipped with bridging means (6, 6'), a planetary gear train (2), several hydraulic receivers (E.sub.i, F.sub.i) assuring the switching of planetary gear train (2), and a hydraulic distributor (16, 17) delivering a line pressure PL, which makes it possible to feed selectively receivers (E.sub.i, F.sub.i) under the control of a computer, according to the data concerning the operation of the vehicle equipped with the transmission, characterized in that at least one switching element (8) is dimensioned to be able to slip in a controlled manner, particularly when converter (1) is bridged, in response to a momentary reduction of line pressure PL, and in that this slipping is servocontrolled, by line pressure PL, at set values depending on torque Cm and engine speed .omega.m.

Abstract: The modulation the control of a heat engine associated with an automatic transmission having an electronic control unit includes the steps of initiating a shift of the automatic transmission by the electronic control unit and substantially simultaneously with shifting, delivering a torque modulation signal to an engine torque control element of the engine for reducing engine torque during shifting.

Abstract: An electromechanical device for easily selecting and engaging different driving modes while an automatic transmission of a motor vehicle is in a forward driving position. Push buttons are positioned so as to be within easy reach of a driver's fingers while the driver is operating the motor vehicle. Each push button corresponds to a particular driving mode. By pressing a push button the gear needed to effectuate the selected mode of operation is activated. The push buttons are electrically connected to a digital control means which controls the implementation and cancellation of the gears used for realizing the selected driving mode.

Abstract: The device is mounted on the cable control (1) of the fuel metering system of the engine, and includes mobile contacts (10) and (11) mounted on a contact-holding piece (28) solid with sheath (2), the mobile contacts (10, 11) working with stationary contacts (13) and (12) mounted on conductive tongues (15) and (14) placed in the upper part (16) of the switch. The contact-holding piece (28) is returned into position by a spring, which rests on the lower part (5) of the switch so that for a non-zero force on contact-holding piece (28) the circuit opens between contacts (11) and (12), and (10) and (13). The spring is calibrated so that the return force that it exerts, when the mobile unit of the contact-holding piece (28) comes against stop (22) of lower part (5) of the switch, is less than the force necessary to open the fuel metering system of the engine from its idle position.

Abstract: Control device of an automatic transmission having four forward speeds with shifting under torque together with a hydrokinetic torque converter with an integrated torsional damper, and one reverse speed, of the type comprising a planetary gear train controlled by three clutches and two brakes with hydraulic control. A hydraulic distributor controlled by four solenoid valves selectively feeds the clutches and brakes, depending on the running conditions of the vehicle. The control means of the solenoid valves are made to use two states of one of these solenoid valves to allow fast filling and progressiveness of the active receiver or receivers during shifting and two states of the other solenoid valves to assure the various sequences during shifting.

Abstract: Pressure control device comprising a manual valve (VM) associated with a pressure control valve (VRP), includes a first line pressure (P.sub.L), defined by two calibrated jets in series, which are placed on a duct set at zero pressure by the manual valve (VM) being in a first position R. At a second line pressure range (P.sub.L), a duct is fed at line pressure (P.sub.L), the manual valve (VM) is in a second position A. A variation of line pressure (P.sub.L) is assured by a modulating solenoid valve (EVM), which establishes a modulated pressure (P.sub.M) acting on a differential section (.SIGMA.) of said pressure control valve (VRP).

Abstract: Two-level pressure control device has a pressure control valve VLP 3 associated with a system of jets and in series to obtain a first reference pressure level P.sub.1 and a second reference pressure level P.sub.2.

Abstract: A device for controlling the supply pressure of a hydraulic actuator for an automatic transmission of an automobile. A pressure modulator varies the hydraulic pressure depending on the output of a controller. The controller receives input information on engine speed, turbine speed, engine load and vehicle speed. The transmission is controlled to be disengaged when the automobile is stopped, and reengaged smoothly.

Abstract: Automatic transmission with stepped ratios for vehicle, characterized in that it comprises a system inhibiting untimely changes to the higher ratio, which system is arranged so that, on the one hand it generates a negative acceleration curve (3) located mainly below the up shift (1) and down shift (2) curves and an increasing throttle opening curve (4) located slightly above the negative acceleration curve and, on the other hand, it only enables the shift up to the higher ratio if the value of the opening (.alpha.c) settles down, i.e. stops varying for a minimum time and if the corresponding configuration point in the plane of the vehicle speeds and throttle openings lies either between the up shift curve (1) and the negative acceleration curve (3) if the opening varies in the decreasing direction, or between the increasing opening curve (4) and the up shift curve (1) if the opening varies in the increasing direction.

Abstract: The invention relates to an automatic change-speed transmission mechanism, notably for motor vehicles, of the type providing the forward speeds and a reverse transmission ratio, of the type comprising two clutches and an idle pinion mounted on the output shaft and formed with an axially-extending integral hub constituting the hub of a second clutch. The housing of the first clutch is adjacent to the side face of said idle pinion, to the side face of the hub of said second clutch and to the housing of the second clutch.