Patent ID: 7143855
Filing Date: 2006-12-05
Classification: B60K,B60W

Abstract:
1. A method of controlling a shiftable clutch in a drive train between a front axle and a rear axle of a four-wheel drive motor vehicle, the method comprising the acts of: driving one axle directly; driving the other axle coupled as a hang-on system by way of the shiftable clutch; continuously acting upon the shiftable clutch with torque in an adjustable manner by way of a pilot control measure; determining values for an inequality of wheel tires between the front and the rear axles using a tire tolerance logic; determining a distortion of the drive train based on the determined values, wherein values of the wheel tire inequality between the front axle and the rear axle is measured in a form of a tire diameter deviation and, wherein determining the tire diameter deviation, comprises the acts of opening, in a neutral driving condition, the shiftable clutch; and determining a rotational speed difference between the front axle and the rear axle when the clutch is opened.