| 摘要 |
The invention relates to a method for operating an exhaust gas purification system of a motor vehicle combustion engine, comprising an SCR-catalyst for the selective catalytic reduction of nitric oxides, in which a reduction means comprising ammonia is added to the exhaust gas at a dosing rate (D) that can be predetermined and that results from a base value and an adoption factor correcting the base value. A test procedure is carried out from time to time in order to check, and if necessary, adapt the adaptation factor. According to the invention during the test procedure a first nitric oxide value of the exhaust gas is compared to a second nitric oxide value of the exhaust gas, wherein the first nitric oxide value and the second nitric oxide value are determined by means of the same nitric oxide sensor (8) arranged downstream the SCR-catalyst (4). In the process, the first nitric oxide value is determined when the dosing of the reduction means is switched off and the second nitric oxide value by the dosing the reduction means at a test dosing rate (Dp)that can be preselected. |
