Patent ID: 6401451
Filing Date: 2002-06-11
Classification: B01D,F01N,Y02T

Abstract:
A system for discriminating degradation of an exhaust purification system of 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 adsorbent, the bypass exhaust gas passage being opened by a switch-over valve at starting 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:an HC sensor installed in the bypass exhaust gas passage at least one of a first position at the adsorbent and a second position downstream of the adsorbent for detecting concentration of HC introduced in the bypass exhaust gas passage in an adsorption mode where the adsorbent adsorbs HC; and adsorbent degradation discriminating means for comparing the detected concentration of HC with a threshold value and for discriminating whether the adsorbent has degraded based on a result of comparison.