Exhaust gas after-treatment device

Abstract

An automotive exhaust system has an exhaust pipe (11) with a reduction agent inlet with dosing valve (10) upstream from a NOx selective catalytic reduction converter. In the vicinity of the valve, the exhaust pipe is shaped to minimize the direct release of heat to the valve, and / or to facilitate the direct release of heat to the valve.

Description

technical field [0001] The invention relates to an exhaust gas aftertreatment device. Background technique [0002] In order to reduce the nitrogen oxides contained in the exhaust gases of internal combustion engines, methods for selective catalytic reduction ("SCR") have proven advantageous for internal combustion engines operating with excess air. In this method, nitrogen oxides are converted together with ammonia into nitrogen and water in a selective catalyst. The reducing agent required for the catalytic conversion of nitrogen oxides is carried in the vehicle instead of ammonia in the form of an aqueous urea solution, from which ammonia can be released in the amount required for the corresponding conversion by pyrolysis and hydrolysis of the urea solution. The aqueous urea solution is introduced into the reduction catalytic converter via a metering device, in particular a metering valve, via the exhaust pipe. The exhaust gas can have a very high temperature, which can...

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Problems solved by technology

However, this additional active cooling circuit is associated with a high technical and economical investment

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