EXHAUST GAS PURIFICATION DEVICE AND METHOD FOR ENGINE, AND SYSTEM FOR REGENERATING FILTER RELATED TO EXHAUST GAS PURIFICATION DEVICE FOR ENGINE

An exhaust gas purification apparatus for an engine is provided with a filter arranged in an exhaust passage of the engine, and a regeneration control unit for regenerating the filter by burning the particulate matters accumulated in the filter. The control unit may include an over-accumulation state determination unit and a switch. The over-accumulation state determination unit determines over-accumulation of the particulate filter in the filter when the particulate matter is over-accumulated in the filter. The switch switches a regeneration temperature for regenerating the filter between a first regeneration temperature at which a normal regeneration is performed and a second regeneration temperature which is lower than the first regeneration temperature. The control unit is connectable to a command unit when the particular matter is over-accumulated in the filter, so that the switch is forcibly operated toward the second regeneration temperature.