Patent ID: 8087239

Claim:
A reductant delivery unit for selective catalytic reduction (SCR) after-treatment for vehicles, the reductant delivery unit comprising: a solenoid fluid injector constructed and arranged to be associated with an exhaust gas flow path upstream of a SCR catalytic converter, the fluid injector having a fluid inlet and a fluid outlet, 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, supply structure separate from and external of the fluid injector and in fluid communication with the fluid inlet, the supply structure including a supply tube and a flange sealed to a body of the fuel injector, the supply tube being in fluid communication with the flange and extending from the flange, the supply tube being constructed and arranged to be coupled with the source of urea solution to deliver urea solution to the fluid inlet, and a heat shield substantially surrounding the injector, the flange being constructed and arranged to be removably coupled to the heat shield, wherein the supply tube is constructed and arranged to be heated by a heat source so that an entire volume of the urea solution delivered to the fluid inlet is heated.