EXHAUST GAS PURIFICATION DEVICE

摘要

An exhaust gas purification device 1 is equipped with a plurality of branch exhaust passages 2 and 3; a junction exhaust passage 110; a shutoff valve 4 switching between allowing and shutting off the flow of exhaust gas to the respective branch exhaust passages 2 and 3; a nitrogen oxide adsorbing material 5 temporarily adsorbing nitrogen oxides in an excess air atmosphere and detaching the adsorbed nitrogen oxides in a reducing atmosphere and reducing the nitrogen oxides in the reducing atmosphere to produce ammonia; a first combustion device 6, disposed on the exhaust upstream side of the nitrogen oxide adsorbing material 5 and having an air supply unit, changing the air supplied from the air supply unit into the reducing atmosphere; and a selective reduction catalyst 19, provided inside the junction exhaust passage 110, selectively reducing the nitrogen oxides by using ammonia as a reducing agent.