System detects malfunction of vehicle exhaust gas treatment device including two particle filters arranged in series by detecting pressure upstream and downstream of upstream filter

摘要

A system detects the malfunction of an exhaust gas treatment device including two particle filters arranged in series. The system detects pressure upstream and downstream of the upstream filter. An oxidation catalyst, for eg. Pt or Cu, is upstream of the filters. The downstream filter may be a catalytic filter. The system may have a first sensor measuring the pressure difference of exhaust gases, eg nitrogen oxides, across the upstream filter and a second sensor measuring the pressure downstream of the upstream filter. Malfunction of the first filter is indicated when the differential pressure is below a minimum value and the downstream pressure is above a maximum value. Malfunction of the first filter is also indicated when the differential pressure is above the minimum value and its value does not change in use.