Failure detecting system of exhaust purification apparatus

Abstract

A failure detecting system of an exhaust purification apparatus includes, a catalyst unit including an electrically heated catalyst and intervened in an engine exhaust path, an air pump supplying a secondary air to the engine exhaust path, a first electric current sensor detecting electric current value for the electrically heated catalyst, and a second electric current sensor detecting electric current value for the air pump. The electrically heated catalyst and air pump are supplied with current upon a cold start of an engine. Presence of failures in the electrically heated catalyst and air pump is discerned on the basis of the electric current value each of the first and second electric current sensors, and the detection of the current value of the first electric current sensor starts prior to the detection of the current value of the second electric current sensor.

Dependencies are inferred from the claim text.