Method for operating a drive device and corresponding drive device

A drive device comprising:

• an engine;
• an exhaust gas aftertreatment device comprising an oxygen storage device having a target fill level;
• a first lambda sensor arranged upstream of the exhaust gas aftertreatment device and configured to measure a first value of residual oxygen content of the exhaust gas upstream of the exhaust gas aftertreatment device, wherein the first lambda sensor is a broadband lambda sensor;
• a second lambda sensor arranged downstream of the exhaust gas aftertreatment device and configured to measure a second value of residual oxygen content of the exhaust gas downstream of the exhaust gas aftertreatment device, wherein the second lambda sensor is a jump lambda sensor;
• and
• a control circuit configured to:
• carry out lambda control of the engine;
• determine a composition of a fuel-air mixture supplied to the engine based upon the first measured value and the second measured value;
• adjust an oxygen filling level of the oxygen storage device of the exhaust gas aftertreatment device to the target fill level based upon the first measured value and the second measured value, after an occurrence of a value of the second measured value, which corresponds to a boundary value of a fill level range that accommodates the target fill level:
• adjust the composition of the fuel-air mixture supplied to the engine to change an oxygen fill level by a pilot oxygen amount exclusively in a direction of the target fill level and not exceeding the target fill level;
• and
• during a regulation period,
• adjust the composition of the fuel-air mixture supplied to the engine until the second measured value is at least within an unavoidable tolerance equal to a target value corresponding to the target fill level;
• and
• correct the pilot oxygen amount by an oxygen balance value determined during a control period.