Abstract: A reductant delivery unit (RDU) delivers supplied reductant (aqueous urea solution) to the engine exhaust system. The delivered reductant is transformed into ammonia which then reacts with the exhaust oxides of nitrogen in a catalytic environment to produce nitrogen and H20. The reductant must be metered to coincide with the amount of NOx present in the exhaust, and also present sufficient spray quality of the delivered fluid to promote good mixing of the ammonia with the exhaust gas. The RDU is a liquid-cooled, making the RDU suitable for very high temperature environment applications.

Abstract: 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.

Abstract: 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.