Exhaust purifying apparatus and method for controlling exhaust purifying apparatus

An exhaust purifying apparatus comprising:

• a filter device, the filter device including:
• a particulate matter trapping filter arranged in an exhaust pipe of an internal combustion engine, the particulate matter trapping filter being made of an electrically conductive material;
• and
• two electrodes fixed to an outer surface of the particulate matter trapping filter;
• a resistance value obtaining unit including a controller configured to obtain an electrical resistance value between the two electrodes;
• an energy supplying unit configured to supply energy converted into heat received by the particulate matter trapping filter;
• and
• the controller further configured to execute a filter regeneration process and a soot burning process, the filter regeneration process eliminating soot deposited in the particulate matter trapping filter with the energy supplied by the energy supplying unit, the soot burning process eliminating soot deposited in a gap portion between the particulate matter trapping filter and the exhaust pipe with the energy supplied by the energy supplying unit, wherein
• a total amount of the energy supplied by the energy supplying unit during the filter regeneration process is larger than a total amount of the energy supplied by the energy supplying unit during the soot burning process, and
• the controller is configured to execute the filter regeneration process when the electrical resistance value obtained by the resistance value obtaining unit is less than a predetermined first determination value and execute the soot burning process when the electrical resistance value is greater than or equal to the predetermined first determination value and less than a second determination value that has been set in advance to be larger than the predetermined first determination value.