Patent ID: 8321102

Claim:
A method for controlling a drive train of a motor vehicle comprising a drive engine, an automated transmission, and an automated clutch, arranged in a force flow between the drive engine and the transmission, the drive engine being controllable by an engine control unit and the transmission, together with the clutch, being controllable by a transmission control unit, both the engine and the transmission control units being connected to one another, via data and sensor lines, and to at least one speed sensor, an actuating sensor of a gas pedal, and an actuating sensor of a brake pedal, the method comprising the steps of: entering a coasting operation mode by performing, with a transmission controller, the steps of, verifying the gas pedal is unactuated, verifying the brake pedal is one of unactuated and actuated less than an actuating limit at which emergency braking occurs and the clutch automatically disengages, and verifying that the clutch is engaged and the motor vehicle is decelerating by a tractive resistance of the drive engine; while in the coasting operation mode: carrying out automatic coast downshifts as a function of at least one of a current driving speed (v F ) and a current engine speed (n M ), preventing coast downshifts when at least one of: the current driving speed (v F ) of the motor vehicle reaches or is below a previously defined threshold speed (v Gr ) for coast downshifts (v F <=v Gr ), and a currently engaged gear (G i ) corresponds to a previously defined limit gear (G Gr ) for coast downshifts (G i =G Gr ), and carrying out an adaptive shift for a transition into a tractive mode upon actuation of the gas pedal (x FP >0) and when one of the current driving speed ( vf ) is below the threshold speed (v Gr ) and the limit gear (G Gr ) is engaged, and preparing for a transition into the traction mode by determining a current target gear (G Z ) and an associated shifting speed (n S ) of an adaptive shift for the transition into the traction mode, as a function of at least one of the driving speed (v F ) of the motor vehicle and the engine speed (n M ) of the drive engine.