METHOD FOR SPECIFYING A MALFUNCTION OF AN EXHAUST GAS RECIRCULATION SYSTEM OF A MOTOR VEHICLE INTERNAL COMBUSTION ENGINE, AND CORRESPONDING DIAGNOSTIC DEVICE

摘要

The invention relates to a method for specifying a malfunction of an exhaust gas recirculation system (8, 9) of a motor vehicle internal combustion engine (1), having the following method steps: setting (S1) a first operating point of the internal combustion engine (1) and a first operating state of the fresh air/exhaust gas system as the vehicle preparation process in a first measurement setting; measuring (S2) volumetric efficiencies of the internal combustion engine (1) for the first measurement setting and for at least one additional measurement setting, comparing the measured volumetric efficiencies with a characteristic field for volumetric efficiency values of the internal combustion engine (1), said characteristic field being stored in a memory unit (2a), and ascertaining the presence of a malfunction in the exhaust gas recirculation system (8, 9) using the result of the comparison; and specifying (S3) the malfunction of the exhaust gas recirculation system (8, 9) while taking into consideration the measurement results for the first measurement setting and for the at least one additional measurement setting and the stored characteristic field for volumetric efficiency values.