摘要 |
The invention provides a process for diagnosing defects in an exhaust gas recirculation device of an internal-combustion engine system having an engine timing gear with a knock control. According to the invention, the firing point is advanced until a predetermined minimal knock control displacement is reached, at a time when the engine is operating in steady-state conditions and the exhaust gas recirculation device is active. Subsequently, the exhaust gas recirculation rate is reduced while the advanced firing point is maintained, and it is determined whether the knock control frequency or the knock control displacement change. If not, a defect in the exhaust gas recirculation device is concluded.
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