FIELD: internal combustion engines.
SUBSTANCE: method of diagnosing (200) nitrogen oxide trap associated with an internal combustion engine, wherein said trap is configured to reduce nitrogen oxides accumulated therein by reaction with engine fuel during recovery phase (120, 130) of catcher, wherein said regeneration stage (120, 130) takes place when switching engine settings to rich mixture, wherein engine torque is obtained based on injection of at least a main amount of fuel, and fuel for nitrogen oxides reduction is obtained from auxiliary fuel amount injection, wherein said method comprises step (230) determining weight of reducing agents (Mred) consumed during the regeneration step, step (240) for comparing said mass (Mred) with failure threshold (S), below which it is determined that the trap is faulty.
EFFECT: it finds an advantageous application in the form of an on-board diagnosis of a motor vehicle equipped with a diesel engine associated with a trap for nitrogen oxides.
8 cl, 8 dwg
