EXHAUST EMISSION CONTROL DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of enhancing flexibility of an arrangement space, while suppressing freezing of urea water remaining in a supply circuit.

SOLUTION: The exhaust emission control device includes: the supply circuit 17 for supplying urea water stored in a urea water tank 16 to an injection nozzle 11; a pump 14 for generating negative pressure in the supply circuit 17; a drain circuit 18 for guiding surplus urea water left after being injected from the injection nozzle 11 to a urea water tank 16; a controller 7 for controlling the pump 14; a gas phase circuit 18a communicated with a gas phase portion 16b in the urea water tank 16; and a switching valve 15 which causes urea water in the urea water tank 16 to be supplied from the supply circuit 17 to the injection nozzle 11 when an engine 5a is driven, then causes surplus urea water to return from the drain circuit 18 to the urea water tank 16 and to be circulated, causes gas to be introduced to the gas phase circuit 18a and causes it to circulates from the gas phase circuit 18a to the supply circuit 17 and the drain circuit 18 when the engine 5a is stopped.

COPYRIGHT: (C)2012,JPO&INPIT