Exhaust emission control device of internal combustion engine

摘要

An exhaust gas emission control device of an internal combustion engine comprises: DPF (17), provided in an exhaust passage (11) of a diesel engine (1), for trapping a particulate in an exhaust gas; ECU (30) for determining whether regeneration of DPF is necessary or not; temperature raising means (16, 30), such as post-injection, for raising the DPF temperature when the ECU determines that the regeneration is necessary; and a temperature sensor (22) for detecting the DPF temperature, and stops control for temperature raise by the temperature raising means, if the DPF temperature detected by the temperature sensor (22) becomes a predetermined temperature or higher when temperature raise control over DPF by the temperature raising means is exercised. If the DPF temperature is the predetermined temperature or higher and a DPF temperature gradient has a negative value, the temperature raising means restores temperature raise control over DPF.