DETERMINATION OF STORAGE CAPACITY OF CATALYST AND APPARATUS

摘要

PURPOSE: To provide a method and an arrangement capable of determining a storage capacity of a catalyst in any steady-state operating condition of an internal combustion engine having the catalyst. CONSTITUTION: Storage capacity of a catalyst 11 is determined by using signalsλ-V andλ-H of a forward probe 13.v and a rearward probe 13.h of the catalyst showing changes from rich to lean and vice versa. The storage capacity SPV is calculated 16 by integrating 14 quantity of oxygen which is absorbed or discharged during a period necessary for emptying the catalyst of oxygen or fill the catalyst with oxygen. Starting of the integration is determined by using a time point of a phase change of the forward probe 13.v, and end of the integration is determined from a phase shift time and a gas passing time. No special test operation of an internal combustion engine 10 is necessary for determining the storage capacity of the catalyst, so that the determination can be carried out in any steady-state operating condition.