Renault S.a.s.

Francois Foussard

Alessandro Monti

Nicolas Romani

Pascal Febrer

Stephane Guegan

Richard Pothin

Marco Marsilia

Philippe Saint Loup

Olivier Boutron

Philippe Saint-Loup

Xavier Claeys

A system for limiting engine torque of a four-wheel-drive motor vehicle, including an actuator that is controlled and configured to distribute the engine torque to the drive wheels, a computer calculating at least one variable characteristic of an operation of the vehicle, and a module for limiting the engine torque. In addition, the limitation system includes a mechanism for deactivating the module for limiting the engine torque according to the variable characteristic of the operation of the engine.

System and method for limiting the engine torque of a four-wheel-drive 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 device distributing engine torque between first and second wheel sets of a vehicle, including a mode switch movable between a first stable position and a second unstable position, activating first and second engine torque distribution modes. When the vehicle stops while the second distribution mode is activated and then restarts after a stop duration, the second distribution mode is activated if the stop duration is less than a time delay, otherwise the first distribution mode is activated. It is determined, in the second distribution mode, whether the vehicle exceeds a predetermined maximum speed threshold. If so, a transition is made to an on-road mode. In the off-road mode, it is determined whether the vehicle exceeds a predetermined intermediate speed threshold, strictly less than maximum speed threshold in an off-road mode, during a time greater than a predetermined duration, to transition back to the on-road mode.

Method and device for distributing an engine torque between two wheel sets of a motor 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 for controlling a speed difference between speed of wheels of a front axle and speed of wheels of a rear axle of a four-wheel drive vehicle. The method: determines an initial speed difference set point based on the speed of the vehicle; determines one or more intermediate speed difference set points based on one or more operational parameters of the vehicle; modulates the initial speed difference set point based on the intermediate speed difference set points to obtain a final speed difference set point; measures the speed difference and compares the measured speed difference with the final speed difference set point; and controls the measured speed difference, so that the measured speed difference reaches the final speed difference set point.

Method for controlling a speed difference between the front wheels and rear wheels of a four-wheel drive vehicle

The invention relates to a four wheel drive hybrid vehicle provided with at least one power train on each wheel set, a first power train () including at least one heat engine, a second power train () including at least one electric machine, the vehicle also being provided with a friction braking system on each drive wheel and sensor (). The control system includes: a means () for distributing a braking request between the friction braking system and at least one electric machine from a power train, said electric machine being capable of producing a resisting torque; a torque instruction modulation means () for modulating torque instructions to braking systems and power trains based on signals coming from the sensors; and a power train control means (); the distribution means (), the torque instruction modulation means (), and the power train control means () being capable of dynamically interacting so as to output torque commands to the power trains and to the friction braking systems with a view to promoting the stability of the vehicle.

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Versailles, France

Francois Foussard