Method for purifying exhaust gas circulating inside exhaust line of heat engine of motor vehicle, involves reducing nitrogen oxide inside exhaust gas by reducing reagent inside selective catalytic reduction downstream element

摘要

The method involves oxidizing an exhaust gas (3) inside a hot zone (ZC), A precursor is injected, where the precursor inside an upstream selective catalytic reduction (SCR) element (SCR1) is pyrolyzed and/or hydrolyzed to obtain a reducing reagent. Nitrogen oxide inside the exhaust gas is reduced by the reducing reagent inside a SCR downstream element (SCR2), where the reducing operation is carried out inside a cold zone (ZF). The injecting is carried out inside the hot zone of the exhaust line.