摘要 |
In an exhaust gas purification system (1) comprising a reducing agent supplying apparatus (17) and an exhaust gas purification apparatus (20) provided in that order from an upstream side of an exhaust passage (3) in an internal combustion engine (E), and a control unit for conducting reducing agent supply control, in which a reducing agent (F) for recovering purification capability of the exhaust gas purification apparatus (20) is supplied into an exhaust gas (G), in regenerating the exhaust gas purification apparatus (20), the concentration of the reducing agent in the exhaust gas (G), which flows into the exhaust gas purification apparatus (20), is varied temporally. According to this constitution, in the regeneration control for recovering the purification capability of the exhaust gas purification apparatus (20), reducing agent supply control in which a temporal change in the regeneration mechanism has been taken into consideration, is carried out, and the reducing agent (F) is supplied in a proper amount to efficiently recover the purification capability. At the same time, the outflow of the reducing agent (F) to the downstream side of the exhaust gas purification apparatus (20) can be prevented.
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