Torque dithering method for controlling a vehicle transmission

摘要

A dithering torque control method that is useful for a semi-automated vehicle transmission facilitates accomplishing a desired condition in the transmission. The method is useful during an initial break torque function to relieve drive train torque so that a driver can move a manual shift lever from an engaged position to a transmission neutral position without using a clutch. The method is also useful for shifting a lever to move gearing components from a neutral position to a next desired gear. A dithering function is used to cyclically oscillate a current torque value about a target torque value that is associated with the desired transmission condition. An amplitude and period of the dithering function are determined based upon an overall gear ratio of the transmission. The dithering function begins at a point dependent on a torque value associated with the currently engaged gear. The dithering function continues until a known transmission condition is confirmed.