Diesel particulate filter system

A diesel particulate filter system for performing a diesel particulate filter forcible regeneration that combusts and removes particulate matter deposited in a diesel particulate filter by injecting fuel from an exhaust pipe injector and oxidizing and combusting the injected fuel with a diesel oxidation catalyst, the diesel particulate filter system comprising:

• temperature sensors on an entrance side and an exit side of the diesel oxidation catalyst to detect a diesel oxidation catalyst entrance temperature and a diesel oxidation catalyst exit temperature, respectively, during the diesel particulate filter forcible regeneration;
• a space velocity ratio determining device that determines an exhaust gas space velocity ratio by measuring a flow rate of exhaust gas during the diesel particulate filter forcible regeneration;
• and
• an injector diagnosing device including:
• a heat-generation region determining unit to which detection values of the temperature sensors and a determination value of the space velocity ratio determining device are input to determine whether or not these values are within a theoretical heat-generation region;
• and
• an actual injection amount diagnosing unit that diagnoses a decrease amount in an actual injection amount of the exhaust pipe injector, when the detection values of the temperature sensors and the determination value of the space velocity ratio determining device are within the theoretical heat-generation region, but not when these values are outside this region.