Based on a visual single-channel test bench

the thickness of particulate layer during regeneration process was measured online by laser displacement sensor. The morphology of the particulate layer was observed offline by scanning electron microscope. The particulate layer thicknesses of two soot particles during both deposition and regeneration processes were compared. The results show that the regeneration process can be divided into three stages based on the change of the particulate layer thickness. In the first stage

the thickness of the particulate layer decreases slowly. In the second stage

the thickness of the particulate layer declines rapidly. This attributes to the oxidation reaction that mainly occurrs at pores in the direction of the flow in a diesel particulate filter. As a result

the particulate layer surface has many irregular pits. In the third stage

the thickness of the particulate layer reduces slowly again. Meanwhile

the morphology of carbon black particles changes from a uniform structure to a chain-shaped one. The particulate layer gains pits as oxidation proceeds.