An exhaust gas aftertreatment device, including a bent exhaust pipe, a mixing pipe having a closed end at the exhaust pipe bend and a bell-shaped widened portion in at least partial contact with the exhaust pipe at its opposite end, and a nozzle connected to a receptacle in the mixing pipe closed end for injecting an additive into the exhaust gases, with a mixing zone in the exhaust pipe between the urea nozzle and the exhaust pipe outlet in which the exhaust gases flow around the mixing pipe symmetrically and form a double eddy in the mixing pipe.