Method and control unit for determining a dead time of an exhaust gas sensor of an internal combustion engine

A control unit for controlling an internal combustion engine and for determining a dead time in a response characteristic of an exhaust gas sensor, comprising:

• at least one of means for measuring an output signal of the exhaust gas sensor and means for determining a characteristic quantity derived from the output signal;
• at least one of means for determining a comparison signal and means for determining a comparison characteristic quantity derived from the comparison signal;
• one of means for determining an undelayed comparison signal or means for determining an undelayed comparison characteristic quantity derived from the undelayed comparison signal;
• means for forming, using a cross-correlation function, a cross-correlation between (i) one of the measured output signal or the characteristic quantity derived from the measured output signal and (ii) one of the comparison signal delayed by a model dead time or the derived comparison characteristic quantity delayed by the model dead time;
• and
• a maximum value recognition unit for the variation of the model dead time and for the recognition of a maximum of the cross-correlation function at the model dead time, wherein the model dead time is selected in such a way that the cross-correlation function assumes the maximum, and wherein the dead time of the measured output signal of the exhaust gas sensor is set equal to the selected model dead time.