Patent ID: 6324893
Filing Date: 2001-12-04
Classification: F01N,Y02A,Y02T

Abstract:
An adsorbent diagnostic apparatus that diagnoses an adsorbent provided in an exhaust passage of an internal combustion engine, the adsorbent adsorbing an unburned gas component in exhaust gas when a temperature of the adsorbent is lower than a predetermined temperature, and the adsorbent releasing previously adsorbed unburned gas component when the temperature of the adsorbent is equal to or higher than the predetermined temperature, the apparatus comprising:an air-fuel ratio detector provided in a portion of the exhaust passage downstream of the adsorbent, the air-fuel ratio detector detecting an air-fuel ratio of exhaust gas flowing in the exhaust passage; anda controller that determines whether the adsorbent has at least one of a fault or a deterioration, based on a detection value of the air-fuel ratio detected by the air-fuel ratio detector, only when a condition exists in which the adsorbent should be releasing a substantially constant amount of the unburned gas component.