Rough filtration heating device, rough filtration heating system and control method of rough filtration heating system

The invention relates to the technical field of automobiles, in particular to a rough filtration heating device which comprises a shell, a filter element, a first-stage heating unit, a second-stage heating unit and a third-stage heating unit. A containing cavity is formed in a shell and communicated with a main oil inlet and a main oil outlet of the rough filtration heating device. The filter element is arranged in the containing cavity so as to divide the containing cavity into a pre-filtering cavity and a post-filtering cavity, the pre-filtering cavity is communicated with the main oil inlet, and the post-filtering cavity is communicated with the main oil outlet. The first-stage heating unit is used for heating the fuel oil in the after-filtering cavity, and the second-stage heating unit is used for heating the fuel oil in the before-filtering cavity, so that wax precipitation of the fuel oil can be prevented, and normal operation of a vehicle is guaranteed. The third-stage heating unit comprises a heating