DPF is the process designed to capture diesel PM or soot physically produced from diesel engine. It has become one of the most effective technologies for control emissions of diesel soot with the filtration efficiency of exceeding 90%, and it shows good thermal and mechanical durability. Particles are normally removed due to deposition mechanisms. The exhaust gas flows through filter, which consists of a fine pore ceramic structure and porous wall inside, during which the PM and soot are then deposited and collected.
DPF can accumulate PM in considerable volume quickly, which would finally cause excessively high pressure drop of exhaust in filter and may harm engine operation. Therefore, filter regeneration (remove particulates from filters) is required to provide enough collection capacity for soot retainment. It can be performed either periodically (after PM has been accumulated in predetermined amount), or continuously during the period of filter operation. In vehicle’s control system, it commonly performs periodically.