DIAGNOSTIC DEVICE FOR MONITORING AN EXHAUST GAS RETURN SYSTEM OF AN INTERNAL COMBUSTION ENGINE

摘要

A diagnostic device for monitoring an exhaust gas recirculation system determines a diagnostic value of the exhaust gas recirculation system without influencing the operation of the internal combustion engine. The diagnostic value depends on the intake pipe pressure and an observer intake pipe pressure. The latter is determined by an observer from one or more further operating variables of the internal combustion engine. The diagnostic device determines that the exhaust gas recirculation system is defective when the diagnostic value lies outside a range of values that depend on at least one operating variable.