Method of controlling a friction clutch in a motor-vehicle transmission

A method of controlling a friction clutch in a transmission of a motor vehicle provided with an internal combustion engine, the method comprising the steps of:

• storing a curve or characteristic of torque transmitted by the friction clutch as a function of the position of the clutch,
• calculating a desired value of the torque to be transmitted by means of the clutch, and
• modifying the position of the clutch so as to bring it to the position to which the desired transmitted torque value corresponds according to the stored curve or characteristic,
• wherein:
• upon the occurrence of predetermined operative conditions, the value of the torque transmitted by the clutch is estimated, by means of an algorithm, as a function of the detected instantaneous values of the torque delivered and of the angular velocity of the shaft of the engine, and the corresponding instantaneous position or estimate position of the clutch is detected,
• the previously stored curve or characteristic is then modified in dependence on the difference between the estimated value of the torque transmitted and that value of the torque transmitted which corresponds to the estimate position according to the previously stored curve or characteristic;
• the stored curve or characteristic comprises a plurality of contiguous, functionally constant sections corresponding to respective adjacent ranges or bands of values of the position of the clutch, the torque values associated with the ends of the range or band in which the estimate position is included are modified in accordance with predetermined procedures, and
• the value of the torque transmitted by the clutch is estimated as a function of the temperature of the clutch.