Drip-irrigation catalytic reduction exhaust pipe

A drip-irrigation catalytic reduction exhaust pipe, comprising:

• an exhaust pipe, which comprises an exhaust gas inlet opening and an exhaust gas outlet opening respectively formed in two axial ends and in communication with each other, the exhaust pipe having a pipe wall in which a plurality of first apertures is formed;
• a plurality of direct-through ceramic filters, which has an outer circumference surrounded by a ceramic fiber material and is arranged in the exhaust pipe in such a way of being lined up, in an axial direction of the exhaust pipe, from the exhaust gas inlet opening towards the exhaust gas outlet opening;
• a wall-flow filter, which is arranged in the exhaust pipe at a location that is closest to the exhaust gas outlet opening;
• and
• a flow guide tube, which comprises a plurality of second apertures, the flow guide tube being arranged outside the pipe wall of the exhaust pipe such that the second apertures respectively correspond to the first apertures, the flow guide tube being connected to a container that receives and holds therein urea liquid, the flow guide tube being provided, at a location thereof, with an electromagnetic valve, which controls passages of the urea liquid of the container through the second apertures and the first apertures to be absorbed by the ceramic fiber material and subsequently penetrating into pores of the direct-through ceramic filters and the wall-flow filter.