Method For Diagnosing Cylinder-Associated Individual Catalytic Converters Of A Multicylinder Otto Cycle Internal Combustion Engine

摘要

The invention relates to a method which is characterized in that before an active catalyst diagnosis is carried out the mixture is dynamically trimmed for all individual catalysts using a signal of a lambda sensor common to the individual catalysts. Once the mixture is successfully trimmed, the cylinder-based forced activation is adjusted in such a manner that the individual catalysts, by virtue of the charge imprinted thereon for a threshold catalyst, exceed their remaining oxygen storage capacity to such an extent that the lambda sensor is enabled to measure the storable charge. The cylinder-based lambda signals reconstructed from the sensor signal are then used to determine specific diagnostic values for every individual catalyst.