DEVICE FOR DETECTING MALFUNCTION IN ELECTRICALLY HEATED CATALYST

摘要

The objective of the present invention is to detect whether an electrically heated catalyst is normal by accurately detecting whether the temperature of the electrically heated catalyst has increased. Therefore, the detection device of the present invention is equipped with: an air-fuel ratio control device (10) that makes the air-fuel ratio rich for the exhaust air flowing into an electrically heated catalyst (4) when an internal combustion engine (1) starts up; a downstream-side detection device (6) provided downstream from the electrically heated catalyst (4) to detect the oxygen concentration in the exhaust air; and a determination device (10) that, when the air-fuel ratio of the exhaust air has been made rich by the air-fuel ratio control device (10) after the internal combustion engine (1) has started, determines whether current is flowing to the electrically heated catalyst (4) on the basis of the time at which the oxygen concentration detected by the downstream-side detection device (6) changes to a value indicating a rich air-fuel ratio.