Particle deposition amount estimation device and exhaust purification system

An apparatus comprising:

• a memory storing processor-executable code;
• and
• a processor in communication with the memory, the processor configured to execute the processor-executable code so as to perform operations that determine a regeneration timing of a particulate filter of an engine, the operations including:
• determining whether an estimated particulate deposition amount on the particulate filter is greater than or equal to a first threshold amount for a first predetermined amount of time;
• and
• determining whether the estimated particulate deposition amount on the particulate filter is greater than or equal to a second threshold amount for a second predetermined amount of time, wherein the second threshold amount is greater than the first threshold amount.

A method of determining a regeneration timing of a particulate filter included in an engine, the method comprising:

• determining, based on at least one sensor signal, that an estimated particulate deposition amount on the particulate filter has failed to meet a first threshold amount for a first predetermined amount of time;
• determining, based on the at least one sensor signal, that the estimated particulate deposition amount on the particulate filter has met a second threshold amount for a second predetermined amount of time, wherein the second threshold amount is greater than the first threshold amount;
• and
• controlling the engine, based on the estimated particulate deposition amount on the particulate filter meeting the second threshold amount for the second predetermined amount of time, to transition from a first regeneration operation to a second regeneration operation.