Method for controlling shifting in a semi-automatic gear transmission

摘要

A method of shift control for an automatic transmission of vehicle power train, having a permanent brake between a drive motor and a final drive, in which current vehicle-specific, road-specific and driver-specific operating parameters, topographical data relating to an upcoming stretch of road ahead of the vehicle are determined while driving, and from which a tractive resistance value for the upcoming stretch of road is determined, and control commands for thrust downshifts and/or upshifts are derived and implemented, within the transmission, during a thrust operation depending upon the tractive resistance value. This is achieved in that the maximum permanent braking force curves that are possible for the upcoming stretch of road, in the currently engaged gear, and each adjacent gear is determined based on the current traveling and engine speeds and analyzed to derive control commands for a thrust downshift and/or upshift in relation to the tractive resistance value.

主权项

1. A method of shift control for an automatic stepped variable speed transmission arranged positioned along a power train of a motor vehicle, which is provided with a permanent brake between a drive motor, designed as an internal combustion engine, and a final drive, the method comprising the steps of:
determining current vehicle-specific, road-specific and driver-specific operating parameters for the vehicle; determining topographical data and an elevation profile, relating to a stretch of road that lies ahead of the vehicle while the vehicle is driving along the stretch of road; determining from the topographical data, the elevation profile, and the operating parameters, a tractive resistance value (FFW(xF)) of the vehicle, for the stretch of road that lies ahead of the vehicle; deriving and implementing control commands for at least one of thrust downshifts and thrust upshifts in an automatic mode of the stepped variable speed transmission, during a thrust operation, depending upon the tractive resistance value (FFW(xF)); determining maximum permanent braking force curves (FBr—max(xF)) that are possible for the stretch of road that lies ahead of the vehicle in a currently engaged gear (G0), and for each gear adjacent to the currently engaged gear, based on a current traveling speed (vF(0)), a current engine speed (MMot(0)) and the tractive resistance value (FFW(xF)); and analyzing the maximum permanent braking force curves (FBr—max(xF)) to derive control commands for the at least one of the thrust downshift and the thrust upshift in relation to the tractive resistance value (FFW(xF)) for controlling operation of the stepped variable speed transmission.