In order to regenerate an activated carbon filter which is seated in a tank
vent line, during idling of the internal combustion engine the
regeneration valve is brought into the maximum open position, and the
throttle valve is simultaneously opened slightly. This produces a higher
air mass flow in the intake tract of an internal combustion engine, and
the proportion of hydrocarbons introduced by the regeneration remains
constant. In order to keep the idling speed of the internal combustion
engine constant, a torque reserve is built up, for example by adjusting
the ignition angle.