ABNORMALITY DETECTION DEVICE FOR EXHAUST GAS RECIRCULATION DEVICE

摘要

Provided is an abnormality detection device for an exhaust gas recirculation device capable of detecting abnormality of an EGR valve while suppressing an influence by a magnitude relation between an intake pressure and an exhaust gas pressure. An electronic control unit (ECU) performs processing for extracting pulsation from an intake pipe pressure value. The ECU performs arithmetic processing for performing fast Fourier transform (FFT) on an output waveform of an intake pressure sensor obtained by sampling processing, and further performs extraction processing for extracting a "frequency component corresponding to the period of exhaust pulsation". The ECU performs processing for determining whether or not the magnitude of the pulse (magnitude of the amplitude) extracted at the step exceeds a threshold value. If the magnitude of the amplitude exceeds the threshold value, the ECU performs processing for determining that there is fully closing abnormality of the EGR valve.