METHOD AND DEVICE FOR DIAGNOSING EXHAUST GAS RECIRCULATION OF AN INTERNAL COMBUSTION PROCESS

摘要

It is necessary to reduce the emission of harmful exhaust gas constituents due to the exhaust-emission standards in effect and in order not to burden the environment any further. Nitrogen oxide emissions (NOx), in particular, can be substantially reduced by means exhaust gas recirculation. A diagnosis of exhaust gas recirculation is therefore imperative. A predeterminate change in the exhaust gas/air ratio lambda and/or in the fresh air mass ml which is used for diagnostic purposes is attained with the assistance of a targeted change in the exhaust gas recirculation rate and by taking into account the features of the exhaust gas recirculation system. If the final value of lambda and/or ml or the change of lambda and/or ml are located within a certain tolerance band, it can be presumed that the exhaust gas recirculation is in order.