Dosing device for dosing aqueous urea solution, into exhaust pipe of internal-combustion engine of motor vehicle, has connecting piece and dosing module, where surface of piece or module possesses specific average roughness in sections

摘要

The device (100) has a dosing module (101), a flange (102) and a connecting piece (103), where the connecting piece is connected with an exhaust pipe (200) by a welded joint. An interior surface of the connecting piece or a surface of the dosing module exposed to reducing agent possesses average roughness in sections, where the roughness is lesser than or equal to 0.02. The surface is polished or chromium-plated. A protective coating is formed on the surface and consists of ceramic and/or metallic nano particles. The connecting piece connects the device to the exhaust pipe.