Patent ID: 7712303
Filing Date: 2010-05-11
Classification: F01N,F02D,Y02T

Abstract:
1. A degradation estimating apparatus, comprising: an unburned fuel component adsorption catalyst, which is provided in an exhaust passage connected with an internal combustion engine and having an unburned fuel component adsorbent for adsorbing an unburned fuel component in exhaust gas emitted from the engine and an oxygen storage component for adsorbing oxygen in the exhaust gas; upstream air-fuel ratio detecting means for detecting an upstream air-fuel ratio in an upstream side of said unburned fuel component adsorption catalyst; downstream air-fuel ratio detecting means for detecting a downstream air-fuel ratio in a downstream side of said unburned fuel component adsorption catalyst; fuel cut means for suspending fuel supply to said engine which is in operation; idle operation implementing means for determining whether said engine is in an idle operation when said suspension of fuel supply to said engine has been canceled; reductant increasing means, for increasing an amount of reductant in the exhaust gas beyond an amount of the reductant in a normal operation, in response to cancellation of the suspending fuel supply conducted by said fuel cut means and when said idle operation implementing means determines that said engine is in the idle operation; and degradation estimating means for estimating a degradation of said unburned fuel component adsorption catalyst on the basis of a first term and a second term, the first term being a period of time, from the cancellation of the suspended fuel supply, until said upstream air-fuel detecting means detects a variation of the upstream air-fuel ratio due to the increase of the reductant quantity in said exhaust gas by said reductant increasing means, and the second term being a period of time, from the cancellation of the suspended fuel supply, until said downstream air-fuel ratio detecting means detecting a variation of the downstream air-fuel ratio due to the increase of the reductant quantity in the exhaust gas by said reductant increasing means.