Process for operating an internal combustion engine comprises a multiple step process in which the nitrogen oxides emissions in the exhaust gas are initially continuously or intermittently measured after the nitrogen oxides storage catalyst

摘要

Process for operating an internal combustion engine comprises a multiple step process in which the NOx emissions in the exhaust gas are initially continuously or intermittently measured after the NOx storage catalyst. Process for operating an engine comprises measuring the NOx emissions in the exhaust gas after a NOx storage catalyst either continuously or intermittently and simultaneously determining a further value for a NOx concentration before the storage catalyst; producing a quotient from the value of the NOx concentration before the catalyst to the NOx measured value after the catalyst and comparing with a first theoretical value; desulfurizing on exceeding the first theoretical value depending on the engine load; measuring the NOx concentration in the combustion exhaust gas after the storage catalyst during desulfurizing and simultaneously determining a further value for the NOx concentration before the catalyst; forming a quotient from the value of the NOx concentration before the catalyst to the NOx measured value after the catalyst and comparing with a second theoretical value. An independent claim is also included for a device for operating an internal combustion engine comprising a NOx sensor (5) arranged in the flow direction after the NOx storage catalyst (4) and connected to a control device (1). Preferred Features: A further NOx sensor is arranged before the NOx storage catalyst and connected to the control device.