Reductant delivery unit for SCR systems having improved deposit resistance

摘要

A reductant delivery unit for selective catalytic reduction (SCR) after-treatment for vehicles includes a fluid injector having a fluid inlet and a fluid outlet. The fluid inlet receives a source of urea solution. An injector flange is coupled directly with an end of the fluid injector and has a flange outlet in fluid communication with the fluid outlet of the fluid injector. The flange outlet is associated with an exhaust gas flow path upstream of a SCR catalytic converter with the fluid injector controlling injection of urea solution into the exhaust gas flow path. Internal surface structure that defines the flange outlet includes a conical surface joined with at least one radius surface. The radius surface is constructed and arranged to resist formation of deposits on the internal surface structure due to break down of the urea solution.

主权项

1. A reductant delivery unit for selective catalytic reduction (SCR) after-treatment for vehicles, the reductant delivery unit comprising:
a 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 an injector flange coupled directly with an end of the fluid injector, the injector flange having internal surface structure defining a flange outlet in fluid communication with the fluid outlet of the fluid injector, the flange outlet being constructed and arranged to be associated with an exhaust gas flow path upstream of a SCR catalytic converter with the fluid injector being constructed and arranged to control injection of urea solution into the exhaust gas flow path, wherein the internal surface structure includes a conical surface joined with at least one radius surface, the conical surface being joined with the at least one convex convex radius surface with a smooth, non-pointed transition, with the at least one convex radius surface being constructed and arranged to resist formation of deposits on the internal surface structure due to break down of the urea solution, the conical surface being downstream of the at least one convex radius surface.