To provide an exhaust emission control device for an internal combustion engine, for surely eliminating deterioration of urea deteriorated material adhered to a tip part of an injection valve.
A catalyst 22 for selectively reducing NOx is disposed in an engine exhaust passage, and the injection valve 30 for aqueous solution of urea is disposed in the engine exhaust passage upstream of the catalyst 22. Change in deterioration rate when the urea in the aqueous solution of urea adhered to the tip part 31 of the injection valve is deteriorated into biuret is followed. When the deterioration rate exceeds a deterioration rate tolerance, the aqueous solution of urea is jetted to dissolve and remove the biuret adhered and accumulated on the tip part.
COPYRIGHT: (C)2006,JPO&NCIPI
Kazuhiro Ito
Shinya Hirota
Toshiaki Tanaka
TOYOTA JIDOSHA KABUSHIKI KAISHA
| JP2003222019A | ||||
| JP2003269145A | ||||
| JP2223625A |
Jun Tsuruta
Tetsuro Shimada
Masaya Nishiyama
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