ARRANGEMENT AND METHOD FOR CONTROLLING THE QUANTITY OF A REDUCTANT INTRODUCED INTO AN EXHAUST LINE OF AN INTERNAL COMBUSTION ENGINE

摘要

An arrangement for controlling injection of a reducing agent in an exhaust line of a combustion engine (1): An injection system (8-12) injects the reducing agent into the exhaust line (3). A first catalyst (13) reduces the amount of nitrogen oxides in the exhaust gases in the exhaust line (3) using the reducing agent. A second catalyst (14) downstream of the first catalyst (13) in the exhaust line (3) converts ammonia in the exhaust gases to nitrogen gas and nitrous oxide. A nitrous oxide sensor (17) monitors the amount of nitrous oxide in the exhaust line (3) downstream of the second catalyst (14). A control unit (10) of the injection system (8-12) adjusts the amount (q) of reducing agent injected into the exhaust line (3) if the sensor (17) detects that the amount of nitrous oxide is not within a selected range (A).