CONTROL METHOD OF EXHAUST GAS PURIFICATION SYSTEM AND EXHAUST GAS PURIFICATION SYSTEM

摘要

At regeneration control while a vehicle mounting an internal combustion engine (10) is parked, both an exhaust throttle valve (13) and an exhaust brake valve (18) are used and if a catalyst temperature index temperature (Tg2) is lower than a predetermined first determining temperature (Tc1) first exhaust gas temperature rise control is conducted that the exhaust brake valve (18) is set to a fully closed side and multiple injection is carried out in in-cylinder fuel injection control, while if a catalyst temperature index temperature (Tg2) is equal to the predetermined first determining temperature (Tc1 or above, second exhaust gas temperature rise control is conducted that the exhaust brake valve (18) is set to an open side, the exhaust throttle valve (13) is set to the fully closed side, and post injection is carried out in the in-cylinder fuel injection control. By this arrangement, while temperature rise efficiency of an exhaust gas flowing into a DPF (12) is enhanced, forced regeneration is carried out efficiently in a short time with avoiding overheat or abnormal combustion at the regeneration control of the DPF (12) while the vehicle is parked.