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A reductant delivery unit (16) is provided unit for selective catalytic reduction (SCR) after-treatment for vehicles. The unit includes a solenoid fluid injector (18) associated with an exhaust gas flow path (13). The injector has a fluid inlet (28) and a fluid outlet (30) with the fluid inlet recei

A reductant delivery unit (16) is provided unit for selective catalytic reduction (SCR) after-treatment for vehicles. The unit includes a solenoid fluid injector (18) associated with an exhaust gas flow path (13). The injector has a fluid inlet (28) and a fluid outlet (30) with the fluid inlet receiving a source of urea solution and the fluid outlet communicating directly with the exhaust flow path so as to control injection of urea solution into the exhaust gas flow path. Supply structure (32) defines the fluid inlet and includes a cup (37) coupled to a body (18) of the injector and a supply tube (29) integral with the cup to define a single member. The supply tube is coupled with the source (27) of urea solution to deliver urea solution to the fluid inlet. The supply tube is heated by a heat source (33) so that an entire volume of the urea solution delivered to the fluid inlet is heated.

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1. 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 havin

1. 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, anda 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. 2. The unit of claim 1, wherein the flange includes a cup coupled to a body of the injector with the supply tube being integral with the cup to define a single member. 3. The unit of claim 1, wherein the flange includes a plurality of flexible tangs extending there-from, an end of the heat shield including a plurality of openings, a tang being received in an associated opening, with the tangs engaging a surface of the heat shield to removably secure the supply structure to the heat shield. 4. The unit of claim 1, wherein the supply structure is molded from plastic. 5. The unit of claim 3, wherein the heat shield is generally cylindrical having an open end with the flange closing the open end, and wherein the heat shield includes openings constructed and arranged to access the tangs. 6. The unit of claim 1, wherein heat shield has opposing first and second ends, a portion of the flange being removably coupled to the first end, the unit further comprising a second flange coupled to the second end of the heat shield, the second flange being constructed and arranged to be coupled to the exhaust gas flow path. 7. The unit of claim 1, in combination with a heater heating the entire supply tube. 8. 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,means for supplying the urea solution, the means for supplying being separate from and external of the fluid injector and in fluid communication with the fluid inlet and 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, andmeans for shielding the injector, the means for shielding substantially surrounding the injector, the flange being constructed and arranged to be removably coupled to the means for shielding,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 of the injector is heated. 9. The unit of claim 8, wherein the flange includes a cup coupled to a body of the injector with the supply tube being integral with the cup to define a single member. 10. The unit of claim 8, wherein the flange includes means for removably securing the flange to an end of the means for shielding. 11. The unit of claim 8, wherein the means for supplying is molded from plastic. 12. The unit of claim 9, wherein the means for supplying is molded from plastic. 13. The unit of claim 8, wherein the means for shielding is a generally cylindrical member having an open end, with the flange closing the open end. 14. The unit of claim 8, wherein means for shielding has opposing first and second ends, the flange being removably coupled to the first end, the unit further comprising and a second flange coupled to the second ether end of the heat shield, the second flange being constructed and arranged to be coupled to the exhaust gas flow path. 15. The unit of claim 8, in combination with a heater heating the supply tube. 16. A method of ensuring that urea solution provided to a reductant delivery unit (RDU) for selective catalytic reduction (SCR) after-treatment for vehicles is heated, the RDU including an injector and being mounted with respect to an exhaust gas flow path so as to inject urea solution directly into the exhaust gas flow path, the method comprising: providing supply structure separate from and external of the fluid injector and in fluid communication with a fluid inlet of the RDU, the supply structure including a supply tube and a flange sealed to a body of the injector, the supply tube being in fluid communication with the flange and extending from the flange, the supply tube being coupled with the source of urea solution to deliver urea solution to the fluid inlet,providing a heat shield to substantially surround the injector,coupling, in a removable manner, the flange to the heat shield, andheating the supply tube so that an entire volume of the urea solution delivered to the fluid inlet of the RDU is heated. 17. The method of claim 16, wherein the step of providing the supply structure includes molding the supply structure from plastic.