Nitrogen oxides trap i.e. catalytic converter, oxygen storage capacity estimating method for vehicle internal combustion engine, involves calculating degradation factor of trap by comparing amount of reducers with reference reducers amount

摘要

The method involves measuring amount of consumed oxygen treating reducers using an oxygen sensor (12) during purging of nitrogen oxides trap (8) when amount of nitrogen oxides contained in the nitrogen oxides trap is lower than threshold quantity of the nitrogen oxides. A degradation factor of the nitrogen oxides trap is calculated by comparing the amount of the reducers during purging of the nitrogen oxides trap with amount of reference reducers. An alarm is triggered when the degradation factor exceeds threshold value.