Renault S.a.s.

Stephane Guegan

Alessandro Monti

Nicolas Romani

Francois Foussard

Pascal Febrer

Philippe Saint Loup

Cedric Chassagnol

Richard Pothin

Pablo Garcia Estebanez

Gabriel Toffolo

A motor vehicle with four drive wheels mounted on first and second axles, including: a transfer shaft connected to the first axle and a controlled coupling that can transfer part of the torque from the transfer shaft to the second axle; a mechanism determining respective speeds of the first and second axles, and a torque distribution control system configured to determine a slip value representative of the speed difference between the first and second axles and to control the coupling. The torque distribution control system is further configured to control the coupling such as to suppress any torque transfer via the coupling when the average slip value over a pre-determined period exceeds a threshold.

Torque distribution control method for a four-wheel drive motor vehicle and corresponding vehicle

A system estimating temperature of a mechanical member of a vehicle once the vehicle has stopped, including: a temperature sensor of a first element of the vehicle, for example a fluid tank; a mechanism estimating air temperature outside the vehicle; a first module estimating temperature of the member when the vehicle is moving; a mechanism storing, while the vehicle is stopped, an outside air temperature, a temperature of the first element, and a temperature of the member; a second module to calculate how long the vehicle has been stopped according to the outside air temperature, the stored temperature of the first element, and the measured temperature of the first element; and a third module to calculate thermal history of temperature variation of the member while the vehicle is stopped, according to the outside air temperature, the stored temperature of the member, and the stoppage time of the vehicle.

Method for estimating the initial temperature of a mechanical member of a vehicle at the start-up of the vehicle

A method managing a device distributing engine torque between main and secondary wheel sets of a motor vehicle, the distributing device including an actuator distributing engine torque, a control unit exhibiting plural distribution modes of the engine torque and adopting one distribution mode as a function of a variable and a button selecting a distribution mode delivering an information item representative of the button position, the control unit determining, in regular operation, the variable, as a function of the information item; the method includes: detecting potential failure of the selection button, including verifying consistency of the information item; activation of degraded mode of operation, when a failure of the button is detected, in which a constant value is allocated to the variable; during degraded operation, monitoring end of failure, including verifying consistency of the information item; activation of regular mode of operation, when end of failure is detected.

Method of managing a device for distributing engine torque upon a failure of its selection button

A splitting of drive torque between front and rear wheelsets includes an actuator to split the torque between the wheelsets, an electronic unit controlling switching of the actuator into a coupled or uncoupled mode, a mechanism electrically powering the electronic unit, and sensors. The electronic unit can make the system adopt: an active operation in which a control signal is generated and the temperature of the actuator is estimated; and a sleep mode in which the temperature of the actuator is not estimated; the switch to sleep mode being authorized: only when the engine is stopped, and if the actuator temperature is below or equal to a threshold or a maximum time period has elapsed.

Method of managing a device that splits drive torque between the front and rear wheelset of a vehicle

A method controlling operation of a mechanism mechanically coupling first and second axles of a transmission system of a motor vehicle, the first axle being driven as standard and the second axle being driven as an option depending on a status of the coupling mechanism, the transmission system being capable of operating in a first mode in which a value of transmittable torque that can be transmitted by the mechanical coupling mechanism is fixed, or in a second mode in which the value of the transmittable torque that can be transmitted by the mechanical coupling mechanism is higher than the value of the transmittable torque for the first mode.

Method for controlling the operation of a means of mechanically coupling the first and second axles of a motor vehicle

A method for managing a turning setpoint applied to at least one turning actuator for rear wheels of an automobile including four steering wheels, the turning setpoint being generated by a turning control unit upon a braking situation with asymmetrical adhesion. The method calculates an intermediate turning setpoint of the rear wheels for compensating a yaw torque generated by a braking with asymmetrical adhesion of the four wheels, transmits an intermediate turning setpoint to the at least one turning actuator for the rear wheels, monitors the value of the intermediate turning setpoint using an acceptation module, and transmits to a braking control unit information generated by the acceptation module of the intermediate turning setpoint.

Method and device for managing a turning setpoint applied to at least one turning actuator for the rear wheels of an automobile

A device and method for monitoring a turn command to a steered rear wheel of a vehicle with at least three steered wheels, in which a steering angle datum value for the steered rear wheel is compared against a template, the comparison being made by a computer that generates the datum value.

Device and method for monitoring the turn command to a steered rear wheel

A device for orientating rear wheels of a vehicle, including: a rear axle fitted with two orientable wheels; an actuator including: a body with a lubricated guide bearing and an actuating member that can move relative to the body, guided by the bearing, and the movements of which orientate the wheels about the vertical of the rear axle; a temperature sensor; and a control circuit for the actuator, configured to lock movements of the actuating member when the temperature determined by the temperature sensor is below a predetermined threshold value.

Device for orientating rear wheels

A method for estimating longitudinal speed of a motor vehicle, including two drive wheels and at least one central electronic unit, based on rotational speeds of the four wheels two of which are drive wheels, such that, after arranging the rotational speeds in descending order: in an acceleration phase, the vehicle longitudinal speed is compared with the speed of the third fastest wheel, and its acceleration should not exceed that of the slowest wheel; in a deceleration phase, the longitudinal speed is compared with the speed of the fastest wheel and its acceleration in absolute value should not exceed that of the second fastest wheel; when the longitudinal speed ranges between the speed of the third fastest wheel and that of the fastest wheel, its value remains constant.

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Versailles, France

Stephane Guegan