Patent ID: 6354076
Filing Date: 2002-03-12
Classification: F01N,Y02T

Abstract:
The system for purifying exhaust gas generated by an internal combustion engine having an adsorbent installed at a bypass exhaust gas passage branched from an exhaust pipe of the engine and merged into the exhaust pipe at a location downstream of the absorbent, the bypass exhaust gas passage being opened by a switch-over valve at a start of the engine to introduce the exhaust gas such that the adsorbent adsorbs unburned HC in exhaust gas generated by the engine and being closed such that the adsorbent desorbs the adsorbed HC and the desorbed HC is thereafter recirculated at a position upstream of a catalyst comprising:a first temperature sensor for detecting at least one of a temperature of the adsorbent and a temperature at a location downstream of the adsorbent; time measuring means for measuring a time until the detected temperature becomes greater or equal to a predetermined value; and adsorbent deterioration discriminating means for discriminating whether the adsorbent deteriorates by comparing the measured time with a threshold value and discriminates whether the adsorbent deteriorates based on a result of comparison.