Adaptive vehicle drive method for extreme operating conditions

摘要

An adaptive torque control and distribution system for a motor vehicle having a transfer case, primary driveline and drive wheels and secondary driveline and drive wheels for operation in extreme off road conditions such as sand. The transfer case includes a modulating clutch and a lockup clutch disposed in parallel between its primary (rear) output and secondary (front) output. The system detects abnormally high magnitude and rapidly repeating wheel spin transients which are characteristic of operation in sand or similar highly randomly variable tractive conditions and overrides the on demand torque distribution program for a predetermined time interval. During this predetermined time interval, the transfer case lockup clutch is activated thereby coupling the primary and secondary drivelines and achieving a fifty- fifty torque split therebetween while the modulating clutch is inactive. The system and this operating mode reduces clutch and clutch operator cycling thereby reducing heat generation within the transfer case and increasing clutch and transfer case longevity.