Diagnostic apparatus and method for adsorbent

摘要

An adsorbent diagnostic apparatus for an emission control apparatus is able to precisely determine whether an adsorbent for adsorbing unburned gas components has a fault or a deterioration. The diagnostic apparatus has an air-fuel ratio detector that is provided in a portion of the exhaust passage downstream of the adsorbent, and a controller that controls the amount of the previously adsorbed unburned gas component released from the adsorbent to the air-fuel ratio detector. Tic controller determines whether the adsorbent has a fault or a deterioration, based on a detection value of the air-fuel ratio detected by the air-fuel ratio detector, when the amount of the unburned gas component released from the adsorbent remains stable.