A method for operating an internal combustion engine, with an injection system having a high-pressure accumulator, comprising the steps of:
- controlling a high pressure in the high-pressure accumulator by a low-pressure suction throttle as a first pressure control element in a first high-pressure control circuit;
- generating, in a normal mode, a high pressure disturbance variable via at least one first high-pressure side pressure control valve as a further pressure control element, via which fuel from the high-pressure accumulator is re-directed into a fuel reservoir;
- controlling, in the normal mode, the least one pressure control valve based on a setpoint volumetric flow for the fuel to be re-directed;
- detecting a variation over time of the setpoint volumetric flow;
- filtering the setpoint volumetric flow;
- and selecting a time constant for the filtering of the setpoint volumetric flow depending on the detected variation over time.