DOSING SYSTEM HAVING RECIRCULATION HEATING AND VACUUM DRAINING

摘要

A reductant dosing system (10) is disclosed. The reductant dosing system may have a supply (16) of reductant, a reductant nozzle (20), and a pump (18) with an inlet (28) and an outlet (30). The reductant dosing system may also have a first passage (32) connecting the supply with the inlet of the pump, and a first control valve (40) disposed in the first passage. The reductant dosing system may further have a second passage (34) connecting the outlet of the pump with the reductant nozzle, and a second control valve (42) disposed in the second passage. The reductant dosing system may additionally have a third passage (48) connecting the second control valve to the first passage at a location downstream of the first control valve, and a fourth passage (50) connecting the second control valve with the supply.