FIELD: internal combustion engines.
SUBSTANCE: there is provided a method for determining the efficiency of exhaust gas purifier (2) of an internal combustion engine, in particular a diesel internal combustion engine (1) in particular for cars, with first NOx sensor (7) located upstream of oxidation catalyst (3) and / or particulate filter (4), and second NOx sensor (8) located downstream of reduction catalyst (5) as well as device (10) for metered supply of reducing agent, wherein signals from both NOx sensors (7, 8) are supplied to control unit (9), by means of which at least one supply amount of the reducing agent is set. According to the invention, it is provided that, in order to determine the efficiency, in particular the efficiency of NO2 production, at least oxidation catalyst (3) and/or particulate filter (4), control unit (9) determines NO and NO2 concentration and/or the NO2/NO of the exhaust gas stream at the measurement point of second NOx sensor (7) and/or downstream of reduction catalyst (5) only based on the detected signal values of both NOx sensors (7, 8). In addition, an apparatus suitable for carrying out such a method is provided.
EFFECT: invention relates to the purification of internal combustion engine exhaust gases.
21 cl, 1 dwg
