| 摘要 |
PROBLEM TO BE SOLVED: To prevent effectively an excessive heat-up of catalyst due to excessive injection of fuel when catalyst is regenerated.SOLUTION: This invention comprises NOx reduction type catalyst 32 arranged at an exhaust system of an internal combustion engine 10 to reduce NOx contained in the exhaust emission and perform purification; and regeneration treatment parts 60, 70 for reducing excess air factor of the exhaust down to a target excess air factor to recover NOx purification capability of the NOx reduction type catalyst 32. The regeneration treatment parts 60, 70 comprise target injection amount calculation parts 66, 76 for calculating at least one target injection amount of post-injection and an exhaust pipe injection required for making the excess air factor of the exhaust to the target excess air factor on the basis of an operating state of an internal combustion engine 10; indicated injection amount setting parts 67, 77 comparing the target injection amount with the predetermined upper limit injection amount and setting a lesser amount as an indicated injection amount; and injection control parts 67, 77 for controlling at least one injection amount of the post-injection and the exhaust pipe injection with the indicated injection amount.SELECTED DRAWING: Figure 1 |
