Patent ID: 7603845

Claim:
A method for managing an operation of a nitrogen oxide trap, and for diagnosing an aging condition of the nitrogen oxide trap for an internal combustion engine, comprising: bleeding said nitrogen oxide trap; observing a change in a significant signal representative of a signal delivered by a first oxygen probe placed on an exhaust line downstream of the nitrogen oxide trap, wherein a unique substantial increase of the significant signal toward a threshold value S 1 from a start of the bleeding the nitrogen oxide trap, obtained after a variation subsequent to a transition of the engine from a lean mixture operation to a rich mixture operation, is an indicator to order an end of the bleeding; determining whether the first oxygen probe operates at a high temperature or a low temperature; when the first oxygen probe operates at the low temperature, integrating the significant signal over a time from the start of the bleeding to the end of the bleeding to determine an integration value, and comparing the integration value with a threshold value S 2 to diagnose the aging condition of the nitrogen oxide trap, and when the first oxygen probe operates at the high temperature, measuring the time elapsed to reach the threshold S 1 from the start of the bleeding to diagnose the aging condition of the nitrogen oxide trap.