摘要 |
In a four-way catalyst for use in connection with an Otto engine, the function of a particulate filter is combined with that of a three-way catalyst (3) (having in particular an oxygen reservoir (4)). In order to check the capacity for separating particles, according to the invention the catalytic function of the three-way catalysts is checked. The extent of damage to the particulate filter (3) can be quantified in particular from a curve pattern after a change in the exhaust gas composition from rich to lean or vice-versa upstream of the particulate filter and the reaction downstream of the particulate filter. |