EXHAUST PURIFICATION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust purification device capable of reducing NOx emissions.SOLUTION: An exhaust purification device 30 comprises: a burner 31 which has an addition valve 38 to add fuel to exhaust gas and an ignition section 33 to ignite the fuel; a filter 40 which collects particulate substances in exhaust gas and includes an absorption catalyst 41 to absorb NOx in the exhaust gas; an HC-SCR catalyst 42 which reduces the NOx with the fuel in the exhaust gas as a reduction agent and generates NHthrough the reduction of the NOx; an NH-SCR catalyst 44 which reduces the NOx with the NHgenerated by the HC-SCR catalyst 42 as the reduction agent; and a control unit 60 which controls the burner 31. The control unit 60 starts addition of the fuel through the addition valve 38 and puts the burner 31 into a combustion state by driving the ignition section 33 when an NOx absorption amount by the absorption catalyst 41 reaches a maximum absorption amount with temperature of the HC-SCR catalyst 42 lower than activation temperature.SELECTED DRAWING: Figure 1