Method for determining a HC conversion capability of a catalytic converter, diagnostic device configured for carrying out the method and motor vehicle with such a device

摘要

The invention relates to a method for determining an HC conversion capability of a catalytic converter (20) arranged in an exhaust gas flow path of an internal combustion engine (12) and designed for converting hydrocarbons (HC) by means of an oxygen-sensitive sensor (30, 32) arranged downstream of the catalytic converter (20) in the exhaust gas flow path ), which has a cross-sensitivity to hydrocarbons. The method comprises the steps of: detecting a first signal (λ2 (t1)) of the downstream sensor (30, 32) in a first situation in which a first HC component is present in the exhaust gas upstream of the catalytic converter (20); second signal (λ2 (t2)) of the downstream sensor (30, 32) in a second situation in which in the exhaust gas upstream of the catalyst () a second HC content is present, which is higher than the first HC content, and - determining the HC conversion capability of the catalyst (20) in dependence on the first and second signal (λ2 (t1), λ2 (t2)) of the downstream sensor (30, 32).