Exhaust gas treatment apparatus for an internal combustion engine comprises a metering device that feeds ammonia on demand into the exhaust pipe upstream of a catalyst

摘要

Exhaust gas treatment apparatus for an internal combustion engine, comprising a selective catalytic reduction (SCR) catalyst in the exhaust pipe and an external ammonia reactor (11) in which urea is converted to ammonia by a thermal process in the presence of water vapor, comprises a metering device (19) that feeds the ammonia on demand into the exhaust pipe upstream of the catalyst.