Volkswagen Ag

Christfried Schroeder

Michael Daetz

The invention relates to a method to determine the HC-conversion efficiency of a catalyst, which is situated in the exhaust gas flow path of an internal combustion engine and which is configured to convert hydrocarbons, by means of an oxygen-sensitive sensor that is installed downstream from the catalyst in the exhaust gas flow path and that exhibits a cross sensitivity to hydrocarbons. The method comprises: detecting a first signal of the downstream sensor in a first situation in which a first HC fraction is present in the exhaust gas upstream from the catalyst; detecting a second signal of the downstream sensor in a second situation in which a second HC fraction that is higher than the first HC fraction is present in the exhaust gas upstream from the catalyst; and determining the HC-conversion efficiency of the catalyst as a function of the first and second signals of the downstream sensor.

Method for determining HC-conversion efficiency of a catalyst, a diagnostic device configured to carry out the method as well as a motor vehicle having such a catalyst

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Meinersen, Germany

Christfried Schroeder