Clutch calibration and control

A method for determining the value of a clutch control parameter signal corresponding to an urge-to-move position of a vehicular master friction clutch drivingly interposed between an engine having a rated engine reference torque and a multi-speed transmission having an input shaft, the method comprising the steps of:

• (a) (i) determining an unloaded engine torque, (ii) preventing rotation of the input shaft, (iii) applying the clutch until a loaded engine torque minus the unloaded engine torque exceeds an urge-to-move reference torque, (iv) sensing a first control parameter signal when the loaded engine torque minus the unloaded engine torque exceeds the urge-to-move reference torque, and (v) releasing the clutch;
• (b) (i) preventing rotation of the input shaft, (ii) applying the clutch in at least one pulse until the loaded engine torque minus the unloaded engine torque is greater than or substantially equal to the urge-to-move reference torque and less than or substantially equal to two times the urge-to-move reference torque, and (iii) sensing a second clutch control parameter signal when the loaded engine torque minus the unloaded engine torque is greater than or substantially equal to the urge-to-move reference torque and less than or substantially equal to two times the urge-to-move reference torque;
• (c) offsetting the second clutch control parameter signal a predetermined amount to determine a clutch control parameter signal corresponding to an urge-to-move position of the master friction clutch.