Hydrocarbon adsorbent state monitoring device

摘要

A characteristic change of a humidity sensor 19 is detected based on the transitional characteristics of output data of the humidity sensor 19 with respect to integrated moisture quantity data representative of an integrated amount of moisture that is supplied to an HC adsorbent 7 by an exhaust gas after an engine 1 has started to operate. Data of characteristics of an individual unit of the humidity sensor 19 is held by the resistance of a resistive element 21 connected to a connector or the like of the humidity sensor 19. A parameter for grasping a state of the HC adsorbent 7 is corrected depending on the detected characteristic change of the humidity sensor 19 and the characteristics of the individual unit of the humidity sensor 19, and the state of the HC adsorbent 7 is grasped based on the corrected parameter. The state, such as a deteriorated state or the like, of a hydrocarbon adsorbent (HC adsorbent) is properly monitored while compensating for the effect of the characteristic change of the humidity sensor and the effect of variations of the characteristics of individual units of the humidity sensor.