Method for controlling an automatic transmission and controller suitable for such a method

A method for controlling an automatic transmission in a drive train of a motor vehicle having a transmission controller selecting and shifting gears of the transmission, which comprises:

• determining a new gear during a gear selection by referring to a gear shift characteristic curve stored in a characteristic diagram;
• generating a gear shift instruction to trigger a gear shift as soon as a working point of the drive train exceeds a corresponding point on the gear shift characteristic curve;
• determining, with the transmission controller, a new gear expected to be engaged shortly and carrying out an initial phase of the gear shift as soon as the working point exceeds a pre-defined distance from the gear shift characteristic curve;
• and
• completing a gear shift as soon as the gear shift instruction has been generated.

In an automatic transmission of a motor vehicle, the transmission having gears, a transmission controller for controlling a transmission ratio, comprising:

• a characteristic diagram memory storing:
• transmission ratios to be set as a function of:
• a torque;
• and
• a variable functionally associated with a speed of the vehicle;
• gear shift characteristic curves;
• and
• preselection characteristic curves lying at a predetermined distance from said gear shift characteristic curves;
• and
• a processor programmed:
• to signal an expected new gear to the transmission and to prepare a gear shifting operation when a working point overshoots said preselection characteristic curves;
• and
• to trigger a gear shifting operation when the working point of the motor vehicle overshoots the gear shift characteristic curves.