EXHAUST PURIFICATION DEVICE AND A CONTROL METHOD THEREOF, CAPABLE OF IMPROVING FUEL EFFICIENCY AND REDUCING EXHAUST GAS

摘要

PURPOSE: An exhaust purification device and a control method thereof are provided to improve fuel efficiency, and to reduce exhaust gas by regenerating a soot filter with a short period.;CONSTITUTION: An exhaust purification device comprises an LNT catalyst, a soot filter, and a control unit. The LNT catalyst adsorbs nitrogen oxides in exhaust gas, and reduces or slips the nitrogen oxides. The soot filter collects particulates in the exhaust gas, and regenerates the particulates using the nitrogen oxides. The control unit selectively forms dense circumstances when the temperature of the LNT catalyst is above first set temperature or the temperature of the soot filter is above second set temperature. The nitrogen dioxide is reduced into nitrogen gas when the temperature of the LNT catalyst is above the first set temperature.;COPYRIGHT KIPO 2013;[Reference numerals] (AA) Start; (BB,DD) No; (CC,EE) Yes; (FF) Return; (S100) Operating an engine; (S110) Measuring an LNT temperature and a DPF temperature; (S120) LNT temperature = First set temperature?; (S140) Reducing desorbed NO_2; (S150) DPF temperature = Second set temperature?; (S160,S130) Desorbing NO_2 by creating a rich atmosphere; (S170) Slipping the desorbed NO_2; (S180) Regenerating a DPF using the slept NO_2