Controlling the automatic starting of a motor vehicle uphill in a μ split situation

摘要

A method is described for controlling the automatic starting of a motor vehicle comprising an electronically controllable locking differential, uphill in a split mu situation. The method comprises the following steps: determining the positive gradient of the underlying surface; defining an initial locking torque on the basis of the determined positive gradient and on the basis of a component of the torque which the vehicle requires to travel uphill with only the first driven wheel powered; calculating the slip ratio SR_xx for the first driven wheel xx according to SR_xx=(V_xx−V_Ref)/V_Crit if the reference velocity V_Ref is between 0 and a critical velocity V_Crit, and according to SR_xx=(V_xx−V_Ref)/V_Ref if the reference velocity V_Ref is higher than the critical velocity V_Crit; and defining the locking torque of the electronically controllable locking differential on the basis of the slip ratio of the first driven wheel.