Patent ID: 8646324

Claim:
A method for dynamically diagnosing an exhaust gas probe ( 17 ) disposed in an exhaust duct ( 18 ) of an internal combustion engine ( 10 ), wherein the dynamic diagnosis is performed after a change in a lambda value of the exhaust gas and on the basis of a comparison of a measured signal rise relative to an expected rise of the signal, characterized in that a target/actual comparison is performed between a calculated O 2 signal ( 26 ) which forms a target value and a measured O 2 signal ( 27 ) which forms an actual value and is measured by the exhaust gas probe ( 17 ), or between signals derived from these signals, wherein, for the target/actual value comparison, a target value ( 42 ) which is assigned to the respective operating point of the internal combustion engine ( 10 ) is formed on an individual basis and subsequently compared with the actual value ( 43 ), and wherein on the basis of the target/actual value comparison a dynamic assessment of the exhaust gas probe takes place, characterized in that the target/actual value comparison is carried out at a step load transition, in that the calculated O 2 signal ( 26 ) and the measured O 2 signal ( 27 ) are filtered for the target/actual value comparison and a calculated and filtered O 2 signal ( 28 ) and a measured and filtered O 2 signal ( 29 ) are formed therefrom, and in that O 2 gradient signals ( 30 , 31 ) of the calculated O 2 signal ( 26 ) and of the measured O 2 signal ( 27 ) or of the filtered O 2 signals ( 28 , 29 ) are determined and used for the target/actual value comparison.