METHOD FOR OPERATING A COMBUSTION ENGINE WITH HC SENSOR INTEGRATED INTO A PURGE GAS LINE

A method is provided for operating an internal combustion engine comprising - an internal combustion engine (6) with a combustion chamber (11), - a fresh gas line (5), - an exhaust gas line (9) with an exhaust gas sensor (25) integrated therein, and - a fuel tank system, wherein the fuel tank system comprises - a fuel tank (1), - a fuel vapor filter (3) which is in fluid communication with an environmental outlet (18), - a ventilation line (2) leading from the fuel tank (1) to the fuel vapor filter (3), and - a purge gas line (4) leading from the fuel vapor filter (3) to the fresh gas line (5), into which - an HC sensor (23) and - a tank ventilation valve (20) and/or a purge gas delivery device (21) are integrated, wherein during operation of the internal combustion engine with purge gas conducted via the purge gas line (4) - the hydrocarbon content of the purge gas is determined by means of the HC sensor (23) as well as the mass flow rate of the purge gas and from these values in combination a fuel mass flow rate which is introduced into the fresh gas line is determined, and - a quantity of fuel introduced by means of at least one fuel injector into the combustion chamber (11) and/or into the fresh gas line (5) is adjusted. From an exhaust gas composition determined by means of the exhaust gas sensor (25), the combustion air ratio of fuel-fresh gas mixture quantities which were supplied to the combustion chamber is monitored with respect to a deviation from a setpoint value, and upon determination of such a deviation, a correction of the measured value of the HC sensor (23) or the fuel mass flow rate determined therefrom is performed or the HC sensor (23) is determined to be defective.