| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine, capable of suppressing a drop in the temperature of a dispersion plate at its site where urea water collides.SOLUTION: A control device 80 acquires an injection pressure at the time of previous urea water injection as a first injection pressure, calculates a second injection pressure which is a urea water injection pressure when injecting urea water at the time of the passage of a predetermined injection period from the previous urea water injection, and also calculates a third injection pressure which is a urea water injection pressure when injecting urea water at a second timing different from an injection timing found from the injection period. When the temperature of a dispersion plate 60 is lower than a threshold value, a first pressure difference as an absolute value for a pressure difference between the first injection pressure and the second injection pressure is smaller than a threshold value, and a second pressure difference as an absolute value for a pressure difference between the third injection pressure and the first injection pressure becomes greater than the first pressure difference with the urea water injection at the second timing, a timing which is the second timing and where the second pressure difference is greater than the first pressure difference is set as a timing for injecting the urea water.SELECTED DRAWING: Figure 1 |
