Patent ID: 7021051

Claim:
A method for forcibly regenerating a catalytic regeneration type particulate filter in an exhaust pipe through which exhaust gas flows, by adding fuel to the exhaust gas upstream of the particulate filter, the added fuel being oxidized on a flow-through type oxidation catalyst before the particulate filter to produce exothermic heat with which captured and accumulated particulates in the particulate filter are burned off, thereby forcibly regenerating the particulate filter, the method comprising, in light-load engine operation areas upon forcible regeneration of the particulate filter, intentionally increasing an engine load using a retarder to brake the engine and increasing an amount of fuel injected so as to compensate reduced torque due to the increased engine load, wherein, upon activation of the retarder, with an accelerator pedal retaining its on-state, in light-load engine operation areas for forcible regeneration of the particulate filter, and when a clutch is off, an intake flow rate is decreased and the amount of fuel injected is increased so as to compensate reduction of the torque due to such decreased intake flow rate.