EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To achieve miniaturization while preventing freezing damage caused by an exhaust emission control solution in solution supply piping. SOLUTION: The exhaust emission control device 14 is provided with a storage tank 17 for storing the exhaust emission control solution 15 injected to an exhaust passage 13 of the internal combustion engine 10, the solution supply piping 22 for guiding the exhaust emission control solution 15 from the storage tank 17 to the exhaust passage 13, and a supply pump 20 disposed in the solution supply piping 22 and force-feeding fluid. An opening and closing valve 33 is provided for selectively introducing the exhaust emission control solution 15 and air in the storage tank 17 into the solution supply piping 22. Return piping 35 communicated with an inside of the storage tank 17 from a piping part on the downstream side of the supply pump 20 in the solution supply piping 22 is provided for collecting the exhaust emission control solution 15 in the solution supply piping 22 in the storage tank 17. A relief valve 41 is provided for releasing a pressure exceeding a set pressure in the piping part on the downstream side of the supply pump 20 in the solution supply piping 22 into the return piping 35. COPYRIGHT: (C)2008,JPO&INPIT