US Patent 9435240 Perforated mixing pipe with swirler

An aftertreatment system may include an exhaust pipe and a mixing pipe. The exhaust pipe receives exhaust gas from an engine. The mixing pipe is disposed in the exhaust pipe and may include a tubular portion and a plurality of blades extending from a longitudinal end of the tubular portion. The tubular portion may include a plurality of openings extending through inner and outer diametrical surfaces of the tubular portion. The tubular portion and the plurality of blades may define an integrally formed unitary body.