Method and control unit for operating a hybrid vehicle

A method for operating a hybrid vehicle that includes an electric machine (3) as a first prime mover, an internal combustion engine (2) as a second prime mover, a separating clutch (4) connected between the internal combustion engine (2) and the electric machine (3), and a transmission (5) connected between the electric machine (3) and a driven end (6), the method comprising:

• in response to a control-side demand to engage the separating clutch (4), implementing an engagement process of the separating clutch (4) during driving under purely electric motor power;
• in response to a control-side demand to implement an upshift in the transmission (5), implementing a gear ratio change from a current gear of the upshift into a target gear of the upshift;
• in response to the control-side demand to engage the separating clutch (4) and the control-side demand to implement the upshift, checking whether the demanded upshift is necessary in order to prevent a vehicle-side rotational speed from reaching or exceeding a rotational speed limit value;
• when the demanded upshift is necessary in order to prevent the vehicle-side rotational speed from reaching or exceeding the rotational speed limit value, prioritizing implementing the upshift in the transmission (5) over implementing the engagement process of the separating clutch (4);
• and
• when the demanded engagement process of the separating clutch (4) has already been initiated and the control-side demand for the upshift is present, checking whether a difference between a synchronous speed of the current gear of the demanded upshift and a current rotational speed of the internal combustion engine (2) is greater than or less than a limit value.