Exhaust-gas cleaning system with nitrogen oxide reduction and with the addition of reducing agent

摘要

An exhaust-gas cleaning system includes a nitrogen oxide reduction catalytic converter for reducing nitrogen oxides which are contained in the exhaust gas. A reducing agent is introduced into the exhaust-gas flow and is in the form of a vapor. A reducing-agent metering device for the metered addition of the reducing agent or a reducing-agent precursor to the exhaust-gas flow includes a vaporizer, which is arranged in the exhaust system upstream of the nitrogen oxide reduction catalytic converter. As a heat source, the vaporizer has (1) a heatable deflector surface, onto which the reducing agent, which is supplied by a feed unit, is directed under pressure; or (2) a microwave generator.