| 摘要 |
Provided is an exhaust injection control method for an exhaust gas post-treatment device whereby the optimal exhaust pipe injection can be performed according to catalyst temperature and the rate of catalyst deterioration when exhaust pipe injection is performed during DPF regeneration. When PM has accumulated on a DPF (27), multi injection, post injection, and exhaust pipe injection are performed, and reducing gas is burned in a DOC (25) to raise the exhaust gas temperature, burn the PM accumulated on the DPF (27), and regenerate the DPF (27). At this time, prepared in advance is a light-off characteristic map (36) obtained by determining burning efficiency relative to DOC temperature during post injection and exhaust pipe injection both when the catalyst is still fresh and after the catalyst has deteriorated, and the catalyst temperature at which exhaust pipe injection is possible is set from the rate of catalyst deterioration on the basis of the light-off characteristic map (36). Multi injection or post injection is performed when the catalyst temperature is less than the set temperature, and exhaust pipe injection is performed when the catalyst temperature is equal to or greater than the set temperature. |
