EXHAUST EMISSION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine capable of effectively combusting PM without causing unburnt residues of PM even when a material with low thermal conductivity is used for a DPF.

SOLUTION: The exhaust emission control device for an engine is provided to an exhaust pipe and includes the DPF for collecting PM in emissions and a filter regeneration means for performing a filter regeneration process for regenerating the DPF. The filter regeneration process includes a DPF elevated-temperature process S3 for elevating a DPF temperature and a normal regeneration combustion process S5 for combusting the PM deposited on the DPF. In this filter regeneration process, an oxygen concentration of the emissions is controlled to a concentration where PM combustion is suppressed when the DPF elevated-temperature treatment is performed and the oxygen concentration of the emissions is controlled to a concentration where the PM combustion is accelerated when the normal regeneration combustion treatment is performed.

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