device for the catalytic tarttamento of exhaust gases of internal combustion engines, in particular diesel engines of motor vehicles, the selective catalytic reduction of nitrogen oxides.

摘要

the invention relates to a device for the treatment of exhaust gases of internal combustion engines with a catalyst for the selective catalytic reduction of nitrogen oxides from the gas.co of diesel engines for motor vehicles with the addition in an amount exceeding the stoichiometric of nh3 or preservative free nh3.with a first sensor which detects the concentration of nh3 in the exhaust gas and interrupts the addition of the amount of nh3 to the achievement of a predetermined upper threshold valueand with a second sensor which detects nh3 adsorbed in the catalyst, by which the addition of nh3 is again restored to the achievement of a predetermined threshold value, inferioror with a single sensor of nh3 in device for the catalytic treatment of exhaust gasthe concentration of nh3 from the detected actual value is compared with a nominal value which,corresponding to the indicated concentration of nh3 to form a correction signal which is used to control the dosing device always inserted in the gaseous phase.