METHOD AND DEVICE FOR DETECTING A NO>x< CONCENTRATION OF AN EXHAUST GAS STREAM PERTAINING TO A COMBUSTION ENGINE

摘要

The invention relates to a method and a device for detecting a NOx concentration of an exhaust gas stream of a combustion engine by means of a NOx-sensitive measuring device, especially a NOx sensor, that is arranged downstream in relation to a NOx storage catalyst in an exhaust gas section of the combustion engine. According to the invention, a search for a minimum (min) of a signal curve (SK) pertaining to the measuring device (18) is carried out in an operational phase of the combustion engine (10), whereby the NOx concentration passes through a value close to zero on the position of the NOx-sensitive measuring device (18) during said phase. The detected minimum (min) is taken over as the zero point for calibrating the measuring device (18).