METHOD OF CONTROLLING INJECTION OF UREA INTO SELECTIVE CATALYTIC REDUCTION SYSTEM Russian patent published in 2013 - IPC F01N3/20 F01N9/00 B01D53/56 

FIELD: chemistry.

SUBSTANCE: method of controlling injection of urea into a system for treating nitrogen oxides with selective catalytic reduction, known as SCR, meant for installation in the exhaust pipe (6) of the engine (2) of a vehicle (1), wherein treatment involves chemical reduction in a catalyst (3), known as a SCR catalyst, of nitrogen oxides by adding ammonia which is contained in urea, the method involving the following steps: measuring temperature of gases in the exhaust pipe (6) of the engine (2) at the input of the SCR catalyst (3); if the measured temperature is higher than a predetermined minimum value, known as minimum injection temperature, a command is issued to inject urea (5); if the measured temperature is lower than the minimum injection temperature, the following sub-steps are executed: determining the mass of ammonia accumulated in the SCR catalyst (3), determining the amount of ammonia needed to convert nitrogen oxides, which exceeds a predetermined value; if the mass of ammonia contained in the catalyst is less than the required amount, a command is issued to activate the mode for heating exhaust gases and injecting urea into the system.

EFFECT: providing optimum treatment of nitrogen oxides while limiting consumption of fuel by the vehicle.

6 cl, 5 dwg