Patent ID: 7404394

Claim:
A method for operating an internal combustion engine having a cylinder and an intake duct with a main path that opens into an inlet of the cylinder, comprising: configuring a tank purging valve to control initiation of a tank purging flow into the intake duct at an inlet point upstream of the respective inlet of the cylinder; configuring a recirculation path in parallel with the main path where the recirculation path has: a recirculation inlet arranged in the main path, a recirculation control element arranged in the recirculation path that controls the opening of the recirculation path, and a recirculation outlet arranged into the main path upstream of the recirculation inlet; and determining a cylinder tank purging fuel mass that flows into a cylinder during the working cycle of the cylinder to a previous measuring in of fuel, where the cylinder tank purging fuel mass is determined as a function of an opening angle of the tank purging valve and an opening angle of the recirculation control element.