Anomaly judgment apparatus for secondary air supply system

摘要

An anomaly judgment apparatus for a secondary air supply system which includes a secondary air supply path for introducing secondary air from an intake path of an engine into an exhaust path at a location upstream of a catalytic converter disposed in the exhaust path. The apparatus includes a pressure detector for detecting pressure in the secondary air supply path, and an anomaly judgment section for calculating pulsation level indicative of the degree of pulsation of pressure detected by the pressure detector and for judging, on the basis of at least the pulsation level, whether or not the secondary air supply system is anomalous. The apparatus further includes an anomaly judgment prohibiting section for prohibiting judgment by the anomaly judgment section when the degree of propagation of intake air pulsation arising in the intake path into the secondary air supply path is equal to or higher than a predetermined level.