Method for regenerating particulate filter

A method for regenerating a catalytic regenerative particulate filter, wherein an oxidation catalyst is provided in upstream of the catalytic regenerative particulate filter incorporated in an exhaust pipe, the method comprising:

• measuring an exhaust temperature between the oxidation catalyst and the particulate filter;
• and
• adding fuel into exhaust gas upstream of the particulate filter such that reaction heat due to an oxidation reaction of the added fuel on the oxidation catalyst causes captured particulate in the particulate filter to burn so as to conduct forced regeneration of the particulate filter,
• wherein, when the measured exhaust temperature between the oxidation catalyst and the particulate filter is lower than a first preset temperature and is equal to or is more than a second preset temperature lower than the first preset temperature, post injection of fuel is added at non-ignition timing following main injection of fuel near compression upper dead center so as to conduct fuel addition, and
• wherein, when the measured exhaust temperature between the oxidation catalyst and the particulate filter exceeds the first preset temperature, the post injection of fuel is stopped and fuel is directly injected into the exhaust pipe upstream of the oxidation catalyst so as to conduct fuel addition.