REDUCING AGENT ADDITION DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a reducing agent addition device which can improve a NOx purification rate with ozone and add a reducing agent in an exhaust passage even though pressure of exhaust therein is high while an air pump is prevented from being contaminated.SOLUTION: A reducing agent addition device comprises: a reaction container 20; an air pump 30p; ozone-containing air piping 26; pressurized air piping 25; a flow regulating valve 25v; a check valve 26v (switch valve); and switch control means 41a. The reaction container 20 forms a reaction chamber 20a to oxidize a reducing agent. The air pump 30p sends air into an ozone generator 30. The ozone-containing air piping 26 introduces ozone-containing air generated in the ozone generator 30 into the reaction chamber 20a. The pressurized air piping 25 introduces air pressurized by a supercharger 11 into the reaction chamber 20a. The switching means 41a switches between an air pump mode to supply the ozone-containing air to the reaction chamber 20a and a supercharger mode to supply the pressurized air to the reaction chamber 20a on the basis of a catalysis temperature and pressure of exhaust.SELECTED DRAWING: Figure 1