Method for detecting efficiency loss of catalytic converter or conversion function of nitrogen oxide trap for motor vehicle, involves emitting alarm signal based on difference of values of pollutant content measurement and threshold

摘要

The method involves determining whether operation of an engine is in a stabilized condition, and automatically modifying a combustion mode of the engine for temporarily producing a mixture richness greater than one when the engine is in the stabilized condition. Content of a pollutant downstream or upstream of the catalytic converter is measured. A mathematical function of the measurement results is compared with a threshold. An alarm signal is emitted based on a difference between a value of the mathematical function and a value of the threshold. An independent claim is also included for a device for detecting an efficiency loss of a catalytic converter of a motor vehicle.