Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method of operating a transmission system of an automotive vehicle, the transmission system including a mechanism of mechanically coupling first and second axles of the transmission system, a status of the coupling mechanism defining a number of transmission modes. In the method, if the automotive vehicle crosses a speed threshold for a determined length of time, for example between 30 seconds and two minutes, the transmission system switches from a first mode in which the torque that can be transmitted by the mechanical coupling mechanism is fixed, into a different transmission mode.

Abstract: 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.

Abstract: A method of operating a transmission system of an automotive vehicle, the transmission system including a mechanism of mechanically coupling first and second axles of the transmission system, a status of the coupling mechanism defining a number of transmission modes. The transmission system includes a button of pulse type controlling selection of a transmission mode and, after the vehicle has stalled, the transmission mode that is active following restarting of the vehicle is the mode that was active before the vehicle stalled.

Abstract: 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.

Abstract: A method for estimating rolling resistance of a wheel of a moving vehicle, the vehicle including at least two wheels fitted with tires, the method including: measuring or estimating a value of angular velocity ? of rotation of at least one wheel; and measuring or estimating a value of torque T applied to the wheel; the method using an observer of dynamics of the wheel that is based on a sliding mode control theory, in which input signals are the value of the angular velocity ? of the wheel and the value of the torque T applied to the wheel.

Abstract: 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.

Abstract: A method of operating a transmission system of an automotive vehicle, the transmission system including a mechanism of mechanically coupling first and second axles of the transmission system, a status of the coupling mechanism defining a number of transmission modes. The transmission system includes a button of pulse type controlling selection of a transmission mode and, after the vehicle has stalled, the transmission mode that is active following restarting of the vehicle is the mode that was active before the vehicle stalled.

Abstract: 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.

Abstract: A method of operating a transmission system of an automotive vehicle, the transmission system including a mechanism of mechanically coupling first and second axles of the transmission system, a status of the coupling mechanism defining a number of transmission modes. In the method, if the automotive vehicle crosses a speed threshold for a determined length of time, for example between 30 seconds and two minutes, the transmission system switches from a first mode in which the torque that can be transmitted by the mechanical coupling mechanism is fixed, into a different transmission mode.

Abstract: 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.

Abstract: 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.

Abstract: A method for determining an estimated value of air temperature outside a vehicle driven by an internal combustion engine, according to which an initial estimated value is attributed to an estimated temperature, the temperature of an intake air of the engine is then measured, and a speed of the vehicle is assessed, followed by a mathematical filtering of the measured temperature of the intake air of the engine. The filtering operation imposes a maximum gradient on the estimated temperature, that has at least two separate positive values over time, either one of the maximum positive gradient values being selected according to the momentary speed of the vehicle.

Abstract: 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.

Abstract: 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.

Abstract: A driving method considering driving situations using at least one effective control signal of a member or group of members of an automobile, the method: making an arbitration between different control strategies each corresponding to a driving context, each control strategy being marked with an identifier continuously calculating an optimal control signal corresponding to each of the strategies; continuously transmitting a value representative of the identifier of the selected strategy; detecting if a strategy identifier change has occurred; when a change is detected, generating a time function x(t) increasing from 0 to 1 over a finite time interval starting when the strategy change has been detected; when a strategy identifier change has been detected, transmitting, during at least one time interval following the identifier change, an effective control signal which is the sum of the optimal signal of the control strategy following the last identifier change weighed by the value x(t) and of the optimal signa

Abstract: 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.