System for determining the gear ratio change in an automatic transmission

The invention is based on an adaptive transmission control wherein changes in the gear ratio of the automatic transmission are determined in dependence upon the detected position of the accelerator pedal actuated by the driver or variables associated therewith and in dependence upon the vehicle straight-line speed and/or the output rpm of the transmission and/or the motor rpm or variables associated therewith. Also, an adaptive variable is determined which adapts the changes of the transmission gear ratio at least to the driving situation then present. The essence of the invention is that the path data of a navigation system is used to determine the above-mentioned adaptation variable. The navigation system is a known map-supported navigation system. In this way, it is advantageously possible to precisely detect the present as well as future driving and environmental situations to which the vehicle is just then subjected or will be subjected in the near future. Accordingly, a very precise estimate of the then existing driving or environmental situation is obtained to which the vehicle is just then subjected or will be subjected in the near future. Shifting strategy can be adapted to these present and future driving situations.