REDUCTANT DELIVERY UNIT FOR SELECTIVE CATALYTIC REDUCTION WITH FREEZE ACCOMMODATION STRUCTURE

摘要

A reductant delivery unit (10') for selective catalytic reduction (SCR) after-treatment for vehicles includes a fluid injector (12) having a fluid inlet (24) and a fluid outlet (25) with the fluid inlet receiving a source of urea solution to be sent through the fluid outlet. Movable inlet cup structure (16') communicates with the inlet of the fluid injector. A shield (18') is fixed with respect to the fluid injector and surrounds at least portions of the fluid injector and the inlet cup structure. A spring (26) is engaged between a portion of the inlet cup structure and the shield. When the urea solution freezes in the fluid injector and expands near the fluid inlet of the injector, the inlet cup structure moves toward the injector inlet to accommodate the frozen urea solution, with the spring returning the inlet cup structure to an initial position once the frozen urea solution melts.