Abstract: The present invention pertains to a process for diagnosing a catalytic converter processing the exhaust gases of a heat engine using a trap that stores and then reduces the nitrogen oxides (NOx) contained in these gases, these reductions being actuated as a function of the storage capacity of the trap. According to the present invention, such a process is characterized in that the oxygen ratio present in the exhaust gases downstream of the trap is measured by a sensor, and in that the storage capacity of the trap is determined by considering the time needed for the sensor to detect a threshold oxygen ratio in these gases during a reduction of the nitrogen oxides (NOx).

Abstract: The present invention pertains to a process for diagnosing a catalytic converter processing the exhaust gases of a heat engine using a trap that stores and then reduces the nitrogen oxides (NOx) contained in these gases, these reductions being actuated as a function of the storage capacity of the trap. According to the present invention, such a process is characterized in that the oxygen ratio present in the exhaust gases downstream of the trap is measured by sensor, and in that the storage capacity of the trap is determined by considering the time needed for the sensor to detect a threshold oxygen ratio in these gases during a reduction of the nitrogen oxides (NOx).

Abstract: The present invention pertains to a process for checking the processing of the exhaust gases of a heat engine, the nitrogen oxides (NOx) contained in these gases being stored and then reduced in a trap modeled in such a way that the reduction of these nitrogen oxides (NOx) is actuated when the storage capacity of the trap, determined according to the model, reaches a threshold (Mthresh). According to the present invention, such a process is characterized in that the modeling of the trap is checked by measuring the quantity of nitrogen oxides (NOx) stored in this trap by means of a sensor located downstream of the trap, and by comparing this measurement to the quantity of nitrogen oxides (NOx) stored, determined according to the model, in order to correct the latter if the measured quantity is markedly different from the modeled quantity.