VANADIUM CATALYSTS FOR HIGH ENGINE-OUT NO2 SYSTEMS

摘要

An exhaust gas purification system for lowering the content of impurities in a lean exhaust gas of an internal combustion engine comprising, a feeding device that feeds ammonia or a compound decomposable to ammonia into an exhaust gas stream containing nitrogen oxides; a selective catalytic reduction catalyst comprising vanadium (V-SCR catalyst) which catalyzes the nitrogen oxides with ammonia in a temperature range of about 150° C. to about 400° C. and at an NO2/NOx ratio of about 0.3 to about 0.9; and a downstream system comprising a diesel oxidation catalyst.