Exhaust emission purifying apparatus and exhaust emission purifying method for engine

Abstract

In an exhaust emission purifying apparatus for an engine provided with: a NOx reduction catalytic converter disposed in an engine exhaust pipe, for reductively purifying NOx with ammonia produced by the urea aqueous solution; and an injection nozzle injection-supplying the urea aqueous solution into the exhaust gas at an upstream position of the NOx reduction catalytic converter, a hydrolytic catalyst that accelerates the hydrolysis reaction by which ammonia is produced by the urea aqueous solution, is applied to at least one of an inner passage of the injection nozzle, the exhaust pipe positioned between the injection nozzle and the NOx reduction catalytic converter, and a diffuser panel diffusing the exhaust gas between the injection nozzle and the reduction catalytic converter, and then, the hydrolysis reaction of the urea aqueous solution being in contact with the hydrolytic catalyst is accelerated, to thereby suppress the deposition of urea in the exhaust pipe.

Dependencies are inferred from the claim text.