Arrangement for controlling the power transmission of a four-wheel drive vehicle

摘要

In this vehicle a main drive axle is driven directly by means of an internal combustion engine by way of a clutch-transmission unit and an additional drive axle by way of a continuously controllable longitudinal clutch. From a reference power output and a vehicle speed a reference traction of all wheels is calculated, from which a control variable for actuation of the longitudinal clutch is obtained by means of a distribution factor varying as a function of operating or drive parameters. The longitudinal clutch can also be actuated at any time either alone or advantageously also in combination with this control variable by a further control variable, which is determined by means of a square of an engine speed differential on the longitudinal clutch, weighted as a function of operating or drive parameters. The vehicle handling thereby obtained makes the vehicle easy to steer with maximum driving safety and traction.