Motor vehicle having at least two drive motors and having an automatic gearbox that has one fixed and one power-split transmission ratio

A method for shifting an automatic transmission in a motor vehicle, the motor vehicle having:

• at least two drive motors, wherein at least one drive motor of the at least two drive motors is an electric motor;
• a high-voltage accumulator;
• an automatic transmission which has at least one fixed gear ratio and at least one power-split gear ratio for gear ratio adjustment starting from the at least one fixed gear ratio;
• and
• an electronic control unit;
• the method comprising:
• relieving the shift element to be opened of the fixed gear ratio to be disengaged in a torque-controlled manner by the at least two drive motors;
• calculating the torque load and observing for the shift element to be opened,
• wherein the torque load is observed with the objective of bringing about a load change by way of a zero crossing in order to establish freedom from load at the shift element;
• controlling, for establishing the freedom from load for the shift element to be opened, a first drive motor of the at least two drive motors and a second drive motor of the at least two drive motors in a power-split manner such that they maintain the gear ratio of the previously engaged fixed gear ratio in terms of speeds and put the shift element to be opened in an at least nearly load-free state in terms of torques, and
• bringing about a load change at the shift element to be opened by a differential speed opposite the calculated torque load at the shift element to be opened being specified at the shift element,
• wherein when a defined threshold value of the observed torque load on the shift element to be opened is exceeded, a sign of the required differential speed on the shift element to be opened is changed for a speed controller.