Patent ID: 7849674
Filing Date: 2010-12-14
Classification: B01D,F01N,Y02T

Abstract:
1. An exhaust emission purifying apparatus for an engine, comprising: a reduction catalyst disposed in an engine exhaust system, for reductively purifying nitrogen oxides with a reducing agent; a reducing agent oxidation catalyst disposed on an exhaust downstream side of said reduction catalyst, for oxidizing the reducing agent passed through said reduction catalyst; a storage tank for storing therein the reducing agent; a reducing agent supply device for supplying the reducing agent from said storage tank to said reduction catalyst; a first discharge-forcing device for forcibly discharging a gas in an upper space of said storage tank to an intake system or said exhaust system on an upstream side of said reducing agent oxidation catalyst; a temperature detecting device for detecting a temperature of said reducing agent oxidation catalyst; and a first operation control device for operating said first discharge-forcing device when the temperature detected by said temperature detecting device reaches an activating temperature for said reducing agent oxidation catalyst or above.