Method and apparatus for controlling wheel slip in a full-time four wheel drive vehicle.

摘要

A center differential (30) offering a full-time two axle drive system. The center differential includes a planetary gear set (40) defining a first drive path which provides an effective torque split ratio to the front axle (18) of the vehicle which is several percent less than the minimum dynamic weight ratio on the front axle assembly. The center differential further includes a bidirectional clutch mechanism (42) defining a second drive path for connecting the driving input to the front drive axle assembly (18) with a drive ratio several percent more than the rear axle ratio. The effective torque split and drive ratios are selected as a function of vehicle weight distribution and tire data for a specific vehicle (10) so as to effect a controlled transfer of torque between the first and second drive paths and before the affected axle assembly reaches its traction limit in any mode of operation.