Reductant delivery unit for selective catalytic reduction

摘要

A reductant delivery unit (10) is provided for selective catalytic reduction (SCR) after-treatment for vehicles. The unit includes a solenoid fluid injector (10) constructed and arranged to be associated with an exhaust gas flow path (14) upstream of a SCR catalytic converter (17). The fluid injector has a fluid inlet (13) and a fluid outlet (15) with the fluid inlet being constructed and arranged to receive a source of urea solution and the fluid outlet being constructed and arranged to communicate directly with the exhaust flow path so as to control injection of urea solution into the exhaust gas flow path. An interface (24) is constructed and arranged to couple the fluid injector to the gas flow path. The interface defines a thermal barrier constructed and arranged to decoupled a body of the injector from exposure to heat in the exhaust gas flow path.