Abstract: A method and a device for determining the oxygen storage capacity of an emission control system in an exhaust duct of an internal combustion engine. In a first phase, the internal combustion engine being operated using an air-fuel mixture having a rich air-to-fuel ratio, and in a second phase, the engine being operated at a lean air-to-fuel ratio; and an oxygen storage capacity of the emission control system being determined from an oxygen input into the emission control system during the second phase; and/or in order to determine a hydrocarbon gas storage capacity, the internal combustion engine being operated during the first phase at a lean air-to-fuel ratio, and operated in the second phase at a rich air-to-fuel ratio; and the hydrocarbon gas storage capacity being determined from the oxygen discharge from the emission control system during the second phase.

Abstract: A method for the dynamic monitoring of a first lambda probe arranged in an exhaust-gas duct of an internal combustion engine upstream of an exhaust-gas purification system. A period of an output signal of the first lambda probe is determined in a controller of the internal combustion engine, and a lambda regulating signal is determined from an output signal of a second lambda probe connected downstream of the exhaust-gas purification system. A first threshold value for a lengthening of the period of the output signal of the first lambda probe is predefined, in that a characteristic signal (46) is derived from the lambda regulating signal, in that a second threshold value for an inadmissible deviation of the characteristic signal (46) is predefined, and in that an inadmissible asymmetric delay of the first lambda probe is inferred if the lengthening of the period exceeds the first threshold value and the characteristic signal (46) deviates from the second threshold value outside predetermined limits.

Abstract: A method and a device for determining the oxygen storage capacity of an emission control system in an exhaust duct of an internal combustion engine. In a first phase, the internal combustion engine being operated using an air-fuel mixture having a rich air-to-fuel ratio, and in a second phase, the engine being operated at a lean air-to-fuel ratio; and an oxygen storage capacity of the emission control system being determined from an oxygen input into the emission control system during the second phase; and/or in order to determine a hydrocarbon gas storage capacity, the internal combustion engine being operated during the first phase at a lean air-to-fuel ratio, and operated in the second phase at a rich air-to-fuel ratio; and the hydrocarbon gas storage capacity being determined from the oxygen discharge from the emission control system during the second phase.

Abstract: The invention relates to a method and corresponding device for diagnosing the dynamics of an exhaust gas sensor, which is disposed in an exhaust gas duct of an internal combustion engine in the direction of flow of the exhaust gas upstream or downstream of a catalytic converter and with which the air/fuel ratio of the gas mixture supplied to the internal combustion engine is controlled via a control circuit. During diagnosis, provision is made for at least one actuator intervention to be specified by means of a control algorithm of a diagnostic controller specifically m the direction of an asymmetric behavior, which is achieved by an extension of one of the two ramps, until the actuator intervention is compensated by an asymmetric dynamic error of the exhaust gas sensor, a reaction to said actuator intervention being used as criterion for assessing an asymmetric dynamic error of said exhaust gas sensor.

Abstract: A method for the dynamic monitoring of a first lambda probe arranged in an exhaust-gas duct of an internal combustion engine upstream of an exhaust-gas purification system. A period of an output signal of the first lambda probe is determined in a controller of the internal combustion engine, and a lambda regulating signal is determined from an output signal of a second lambda probe connected downstream of the exhaust-gas purification system. A first threshold value for a lengthening of the period of the output signal of the first lambda probe is predefined, in that a characteristic signal (46) is derived from the lambda regulating signal, in that a second threshold value for an inadmissible deviation of the characteristic signal (46) is predefined, and in that an inadmissible asymmetric delay of the first lambda probe is inferred if the lengthening of the period exceeds the first threshold value and the characteristic signal (46) deviates from the second threshold value outside predetermined limits.

Abstract: The invention relates to a method for diagnosing the dynamics of an exhaust gas sensor embodied as a lambda probe, which is disposed in an exhaust gas duct of an internal combustion engine in the direction of flow of the exhaust gas upstream or downstream of a catalytic converter and with which the air/fuel ratio of the gas mixture supplied to the internal combustion engine is controlled via a control circuit. During the diagnosis, provision is made in the method according to the invention for at least one actuator intervention to be specified by means of a control algorithm of a diagnostic controller specifically in the direction of an asymmetric behavior, which is achieved by an extension of one of the two ramps, until the actuator intervention is compensated by a possible asymmetric dynamic error of the exhaust gas sensor, a reaction to said actuator intervention being used as the criterion for assessing an asymmetric dynamic error of said exhaust gas sensor.