System and method for sliding clutch engagement under tooth butt or torque lock conditions

Abstract

A system and method are disclosed for controlling a shift event in a transmission wherein a shift actuator develops a force to effect the engagement of a clutch collar and a gear. The method comprises detecting when a non-fully engaged condition of the clutch collar and the gear occurs, indicating either a tooth butt or torque lock condition, and then pulsing the shift actuator, when the non-fully engaged condition is detected, between a relatively low force and a relatively high force to disturb the clutch collar and the gear out of the non-fully engaged condition. The detecting step comprises examining either the axial position of the clutch collar or the axial position of a shift rail operatively connected to the clutch collar with a rail position sensor. Preferably, a signal having a modulated pulse width and a frequency of between about 5 and 20 Hertz is sent to the shift actuator. The system which embodies this method is disclosed in the forms of an automated mechanical transmission having sliding clutch collars and a transmission system having a standard friction master clutch interposed the engine and the transmission.

Dependencies are inferred from the claim text.