METHOD FOR DIAGNOSING A NITROGEN OXIDE TRAP AND ASSOCIATED ENGINE

摘要

A method for diagnosing a nitrogen oxide trap designed to store nitrogen oxides emitted by an internal combustion engine of a motor vehicle, characterised in that it comprises at least steps consisting of: - determining the instant efficiency (&egr;) of the trap; - comparing the instant efficiency (&egr;) of the trap with the instant efficiency (&egr;poll) of a first reference trap; - comparing the instant efficiency (&egr;) of the trap with the instant efficiency (&egr;OBD) of a second reference trap; and - establishing a diagnosis on the condition of the trap from: a first diagnostic criterion (C1) equal to the percentage of the duration (t) of the diagnosis during which the instant efficiency (&egr;) of the trap is greater than the instant efficiency (&egr;poll) of the first reference trap; and a second diagnostic criterion (C2) equal to the percentage of the duration (t) of the diagnosis during which the instant efficiency (&egr;) of the trap is between the instant efficiency (&egr;OBD) of the second reference trap and the instant efficiency (&egr;poll) of the first reference trap.