Abstract: Engine brake clutch device comprising a common system of the electric machine type for transformation of mechanical energy associated with a differential system (27) and with a clutch (28), the unit being placed between the engine and the transmission so as to be able to perform the clutching or the engine braking of the vehicle.

Abstract: A circuit diagnosis and control device adapted to detect defects in a primary electrical circuit and temporarily discontinue power to the primary circuit in the event of a defect. A MOS transistor is connected in series with the power source and the primary circuit. A calculation device is connected with the MOS transistor and periodically tests a first voltage V.sub.GS, which may be different from zero, and a second voltage V.sub.DS, which must be higher than half of the voltage V.sub.BAT of the battery. In the event of a short circuit, the power is temporarily withheld from the primary circuit. An indication lamp may be controlled by the calculation device to inform the driver of the circuit condition. If V.sub.GS is not equal to zero and V.sub.DS is half of V.sub.BAT, a short circuit condition is indicated, for example, by a slow flashing of the indicator lamp. If V.sub.GS is equal to zero and V.sub.DS is less than half of V.sub.

Abstract: Device for detecting the underinflation of a motor vehicle tire (1) serving also as a device for measuring the kinetic state of the wheel, characterized by the fact that it comprises in combination: a toothed wheel turning with the wheel (1) of the vehicle and whose electrical characteristics of at least one (6a) of the teeth (6) are modified by a pressure drop in one of the tires, an electromagnet (10) fixed to rotate and constituting an electromagnetic sensor in which the toothed wheel (4) generates a signal formed from successive pulses, and a computer (23) which computes the values of the successive periods, and which interprets their variation as an acceleration or deceleration or else as a state of underinflation of the tire according to the behavior of this variation.

Abstract: A manual or automatic control method for the gearbox of a vehicle by use of an electronic computer.The electronic computer controls the clutch and the dogs of the gearbox:either through the manual intervention of the driver,or in the event of a "kick down" of the accelerator pedal,or else automatically on the initiative of a processing device 300. The method permits automization of a standard gear box, which can also be supplied in non-automatic form.

Abstract: A method and device for controlling the fork of a synchromesh for a gear box. A command signal sent by the operator is converted into signals by a modulator whose output controls an electric valve to open and close several times in succession. The electric valve controls a jack which in turn controls the fork connected to a sliding gear associated with the synchromesh, whereby the instantaneous pressure of the fluid supplied to the jack is varied during the steps of approach, synchronization, and locking of the synchromesh.

Abstract: A processing device capable of starting the sequence of the speed change operations automatically in the gearbox of a vehicle, such as the automatic transmission of a truck. A first comparator compares the data received from a gearbox condition detecting device and that received from a speed ratio selection device. In the event of a difference, the comparator sends to a gearbox control device either a pulse for increasing by one speed ratio, or a pulse for decreasing by one speed ratio.

Abstract: A processing device capable of starting the sequence of the speed change operations automatically in the gearbox of a vehicle, such as the automatic transmission of a truck. A first comparator (302) compares the data received from a gearbox condition detecting device (500) and that received from a speed ratio selection device (200). In the event of a difference, the comparator (302) sends to a gearbox control device (400) either a pulse for increasing by one speed ratio, or a pulse for decreasing by one speed ratio.

Abstract: A device for selecting the ratio of the gearbox on a vehicle. The ratio is selected by electronic means which include a system for putting the engine speed under the control of the shaft speed, a system defining the ratios allowed, a system for introducing a parameter imposed by the driver, and a safety system with display and alarm means. Electronic memory devices permit taking into account the operating conditions of the engine. The device permits automatic or manual selection of a gearbox ratio corresponding to the greatest allowed ratio.

Abstract: A system for detecting the state of a gear box. Sliding gear selector rods control gear shift forks, and carry notches into which bars may fall. Each of such bars actuates an electrical device for emitting a binary bit. All of the binary bits together form a coded element the reading of which is made with reference to a binary standard to determine the position of the selector rods, which in turn determines the gear ratio or state of the gear box.