Abstract: The inventive method for controlling the gear change of an automatic gearbox provided with distinct shifting rules or variograms used according to a vehicle operating conditions consists in detecting and carrying out gear shifting requests sequential to the shifting rule or variogram switching, subject to the application of specific conditions only.

Abstract: The invention concerns a method for controlling automatic transmission (3) of a vehicle comprising an engine (2) driving the transmission (3) which consists in: detecting a downhill situation of the vehicle, and selecting a transmission ratio so that the engine absorbs energy, storing a longitudinal speed of downhill start (Vmin) when the vehicle starts going downhill, and while the vehicle is running downhill, comparing the current speed (V) of the vehicle with the downhill start speed (Vmin) such that the current speed (V) exceeds the downhill start speed (Vmin) by a predetermined difference (VS), then controlling the transmission to trigger downshifting.

Abstract: A method for adjusting an automatic transmission ratio by a driver includes imposing a ratio change required by the driver to the transmission when first conditions are fulfilled, maintaining the ratio until second conditions for returning to operation in an automatic mode are fulfilled, and automatically restoring the automatic mode when the second conditions are fulfilled.

Abstract: A control for a vehicle including a controller for a propulsion motor unit, which generates a signal representative of the depression of an accelerator pedal operated by the vehicle driver and detects a degradation of the signal. On detection of such a degradation the speed of the vehicle is regulated if above a threshold value and the operating speed of the engine is regulated if the vehicle speed is below the threshold value.

Abstract: The inventive method for controlling the gear change of an automatic gearbox provided with distinct shifting rules or variograms used according to a vehicle operating conditions consists in detecting and carrying out gear shifting requests sequential to the shifting rule or variogram switching, subject to the application of specific conditions only.

Abstract: A control for a vehicle including a controller for a propulsion motor unit, which generates a signal representative of the depression of an accelerator pedal operated by the vehicle driver and detects a degradation of the signal. On detection of such a degradation the speed of the vehicle is regulated if above a threshold value and the operating speed of the engine is regulated if the vehicle speed is below the threshold value.

Abstract: The invention concerns a method for controlling automatic transmission (3) of a vehicle comprising an engine (2) driving the transmission (3) which consists in: detecting a downhill situation of the vehicle, and selecting a transmission ratio so that the engine absorbs energy, storing a longitudinal speed of downhill start (Vmin) when the vehicle starts going downhill, and while the vehicle is running downhill, comparing the current speed (V) of the vehicle with the downhill start speed (Vmin) such that the current speed (V) exceeds the downhill start speed (Vmin) by a predetermined difference (VS), then controlling the transmission to trigger downshifting.

Abstract: A method for automatically controlling the gearbox of a road vehicle uses a computer using information on displacement speed and transversal acceleration of the vehicle and engine load in order to apply various shifting rules according to the road profile. The gearbox computer applies different gear shifting rules according to the value of a coefficient of activity Kbend depending on the displacement speed of the vehicle (V), the lateral acceleration of the vehicle (Gt) and the derivative thereof in relation to time (dGt/dt).

Abstract: The invention relates to a motor vehicle comprising a fully automatic transmission, of the type in which a management unit (20) controls the operation of the engine (10) as a function of torque demand information from a throttle pedal (24), and of the type in which the engine management can be modified as a function of information transmitted by a transmission (16) control unit (22) to the engine (10) management unit (20), characterized in that for certain phases of operation of the vehicle, the transmission (16) control unit (22) inhibits the action of the torque demand information, for which it substitutes an engine management command to which the management unit (20) is subordinated.

Abstract: A method for blocking and releasing gear ratios in a vehicle equipped with an automatic gear box. The process includes combined functions F1, F2, F3 in which F1 is a function for blocking a passage of a transmission ratio during a first time delay, F2 is a function for blocking passage of a ratio in response to an instability of a fuel throttle opening angle, and F3 is a function for blocking passage of a ratio in response to a deceleration of the vehicle.

Abstract: A method for controlling automatic transmission downshift phases. The method determines conditions in which the downshift passes from normal operating conditions based on predetermined passage laws to special downshift operating conditions, and senses the passage to the special operating conditions. On sensing the passage to the special operating conditions, downshifting is effectuated by passing from the current gear ratio to a lower gear ratio, and blocking the lower gear ratio until the special downshift operating conditions disappear.

Abstract: A method for detecting slippery ground in a vehicle with automatic transmission includes detecting the instantaneous running conditions, with the aid of at least one parameter that represents the existence of slippery ground; on the basis of this detection, generating, by counting, a value that represents the change in running conditions as a function of time; comparing the value with reference conditions; as a function of the result of the said comparison, deciding whether or not the instantaneous running conditions correspond to slippery ground.

Abstract: The method for eliminating an oscillation phenomenon in a motor vehicle with an automatic transmission system. The mass of the vehicle is determined on the basis of the measured speed, the current ratio of the transmission, the engine speed and the opening angle of the engine throttle. The acceleration of the vehicle and a higher ratio is predicted from the mass of the vehicle. The total amount of tractive resistance applied to the vehicle is determined. The probability that there will be an oscillation phenomenon at a higher ratio termed "oscillation risk" is determined from the acceleration and tractive resistance information. A signal for preventing shifting to the higher ratio is generated from the oscillation risk information, with the signal being adapted to be applied to a transmission control device.