Combustion engines may include exhaust systems to direct and, in some instances, treat exhaust gases emitted from the combustion engine. For instance, diesel engines may include exhaust system components to treat nitrogen oxide (NOx) compounds that may be emitted in the exhaust gas from the diesel engine. To reduce NOx emissions, a selective catalytic reduction (SCR) process may be implemented to convert the NOx compounds into more neutral compounds, such as diatomic nitrogen, water, or carbon dioxide, with the aid of a catalyst and a reductant. A SCR catalyst may be included in a catalyst chamber of an exhaust system, such as that of a vehicle or power generation unit. The exhaust system may include other components for the exhaust system, such as a diesel particulate filter (DPF), a diesel oxidation catalyst (DOC), or other components. A reductant such as anhydrous ammonia, aqueous ammonia, or urea is typically introduced into the exhaust gas flow prior to the catalyst chamber. To introduce the reductant into the exhaust gas flow for the SCR process, an SCR system may dose or otherwise introduce the reductant through a dosing module that vaporizes or sprays the reductant into an exhaust pipe of the exhaust system upstream of the catalyst chamber.
USPTO Backgrounds
USPTO Backgrounds