Patent ID: 8460156
Filing Date: 2013-06-11
Classification: F16H,Y10T

Abstract:
1. A method of operating a vehicle drive train ( 1 ) with a drive machine ( 2 ) and a transmission device ( 3 ) during a coasting upshift from a current gear ratio to a target gear ratio, during the coasting upshift at least one interlocking shift element ( 6 ) that is engaged in a force flow of the transmission device ( 3 ) to produce the current gear ratio is disengaged from the force flow and also a frictional shift element ( 5 ) that is engaged in the force flow of the transmission device ( 3 ) to produce the target gear ratio is engaged in the force flow, such that when a shift command is given for the coasting upshift, torque (m_ 6 ) applied at the interlocking shift element ( 6 ) is reduced at least approximately to zero, by a defined engine intervention, and the interlocking shift element ( 6 ) is disengaged from the force flow of the transmission device ( 3 ), the method comprising the steps of: issuing a command for the coasting upshift with a control unit; preparing the frictional shift element ( adjusting the defined actuating force of the frictional shift element ( reducing torque applied at the interlocking shift element to at least approximately to zero, by the defined engine intervention and disengaging the interlocking shifting element from the force flow of the transmission device; increasing the actuating pressure of the frictional shift element by the pressure offset value; and fully engaging the frictional shifting element to produce the target gear ratio.