To detect an abnormality of a particulate filter with a high degree of accuracy even in an engine operating condition of a small intake air flow in the engine.
The abnormality detection system includes a predicted pressure difference calculating means for calculating a predicted pressure difference between upstream and downstream sides of an exhaust gas in the particulate filter based on the intake air flow rate in the engine and an area of a part through which the exhaust gas can pass in an exhaust gas passing surface of the particulate filter, and a blocking means for blocking off a part of the exhaust gas passing surface of the particulate filter based on the predicted pressure difference calculated by the predicted pressure difference calculating means. When the predicted pressure difference calculated by the predicted pressure difference calculating means is not more than a given value, the part of the exhaust gas passing surface of the particulate filter is blocked off. Then, based on a predicted pressure difference after the part of the exhaust gas passing surface has been blocked off and an actual pressure difference between the upstream and downstream sides of the exhaust gas in the particulate filter, the presence or absence of the abnormality of the particulate filter is determined.
SAWADA YUTAKA
KITAURA KOICHI
Jun Tsuruta
Tetsuro Shimada
Shinji Mitsuhashi
Yoryo Mihashi
Koichi Ito
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