FIELD: engines and pumps.
SUBSTANCE: invention relates to the method relating to SCR system. The method relates to SCR system where the reducing agent is supplied into the flow of exhaust gases upstream SCR catalyst (260). NOx in exhaust gases is measured upstream and downstream SCR catalyst (260) and any presence of crystals of reducing agent in SCR catalyst (260) is detected. The method contains the stages during which first the supply of reducing agent into the flow of exhaust gases is disabled in such a way that SCR catalyst, in essence, is depleted and doesn't contain the evaporated reducing agent. After that at the temperature at which crystals of reducing agent are evaporated, NOx content upstream and downstream SCR catalyst is measured. These values are compared with each other and, if the difference between the measured NOx content exceeds a certain value, it is accepted as a parameter of presence of crystals of reducing agent in SCR catalyst. The method also includes the statement that NOx content has been measured correctly, and the conclusion that crystals of reducing agent are present provided that NOx content has been correctly measured and the presence of crystals of reducing agent in SCR catalyst (260) has been indicated. The invention also relates to computer software product containing the program code (P) for the method implementation. The invention also relates to SCR system and the motor vehicle (100, 110) which is fitted with this system.
EFFECT: technical result of the invention is improvement of performance data of SCR system and more reliable detecting of presence of undesirable crystals of reducing agent in SCR catalyst in SCR system.
12 cl, 5 dwg
