Patent ID: 8690724

Claim:
A method of operating a drive-train of a motor vehicle comprising a hybrid drive system ( 3 ) comprising an internal combustion engine ( 1 ), at least one electric machine ( 2 ), a transmission ( 5 ), a drive output ( 4 ) and a brake system comprising at least one wear-free permanent brake so that, when a braking torque is required at the drive output ( 4 ), the braking torque being distributed between the at least one electric machine ( 2 ), of the hybrid drive system ( 3 ), and the at least one wear-free permanent brake in such manner that, at the beginning of a braking torque demand, the braking torque is called for and provided at the drive output ( 4 ) exclusively by the at least one electric machine of the hybrid drive system ( 3 ) and, thereafter, as a function of characteristics of the at least one wear-free permanent brake, the braking torque demand being transferred at least in part, in a controlled manner, from the at least one electric machine ( 2 ) to the at least one wear-free permanent brake, such that a sum of the braking torques, provided at the drive output by the at least one electric machine ( 2 ) and the at least one permanent brake, corresponds to a required braking torque, the method comprising the steps of: transferring the braking torque demanded from the at least one electric machine ( 2 ) of the hybrid drive system ( 3 ), in a controlled manner, to the at least one wear-free permanent brake such that the braking torque demanded, from the at least one electric machine ( 2 ) of the hybrid drive ( 3 ), is continuously reduced; continuously increasing the braking torque demanded, from the at least one wear-free permanent brake, in a ramp-like manner so that this continuous and ramp-like transfer of the braking torque demand is determined in advance as a function of characteristics of the at least one wear-free permanent brake and, therefore, occurs in the manner of a pilot-controlled transfer of the braking torque demanded.