Catalyst system's operability evaluating method for use in internal combustion engine, involves evaluating brace of catalyst system, to evaluate operability independently of oxygen storage capacity of main catalyst

摘要

The method involves evaluating the operability of a catalyst system (12) based on an oxygen storage capacity of a front catalyst (FK). A brace (14) of the catalyst system is evaluated to evaluate the operability independently of an oxygen storage capacity of a main catalyst (HK), when the oxygen storage capability of the front catalyst is larger than a threshold value. The oxygen storage capacity of the main catalyst is determined, when the oxygen storage capacity of the front catalyst is assigned to a range of good values or a range of critical parameters. An independent claim is also included for a controller for the evaluation of the operability of a catalyst system of an internal combustion engine.