Method for monitoring oxidation catalyst of selective catalytic reduction system for vehicle diesel engine, involves determining catalyst improper operation when difference between oxygen levels is smaller than predefined level

摘要

The method involves injecting fuel into an exhaust gas flow, which flows upstream of an oxidation catalyst (26) by an exhaust-gas treatment system (20). Oxygen levels in the exhaust gas flow upstream and downstream of the catalyst are measured. Difference between the upstream oxygen level and the downstream oxygen level is calculated. Improper operation of the catalyst is determined when the computed difference between the upstream oxygen level and the downstream oxygen level is smaller than predefined limit oxygen level. The predefined limit oxygen level ranges from 0 to 10%.