Diesel exhaust fluid mixing body using variable cross-section switchback arrangement

A mixer for use in an aftertreatment system for mixing a reductant inserted into the aftertreatment system with an exhaust gas flowing through the aftertreatment system, comprising:

• a housing defining an internal volume, the housing defining at least a first passageway, a second passageway, and a third passageway, the first passageway structured to receive a flow of the exhaust gas and direct the flow in a first direction towards the second passageway, the second passageway structured to redirect the flow in a second direction substantially opposite the first direction towards the third passageway, the third passageway structured to redirect the flow in a third direction substantially opposite the second direction towards an outlet of the housing, the housing further comprising a first partition wall and a second partition wall are positioned in the internal volume defined by the housing, the first partition wall and the second partition wall oriented so as to define the first passageway, the second passageway and the third passageway;
• and
• an injection port defined on a sidewall of the housing, the injection port structured to allow a reductant to be inserted into the housing,
• wherein the first partition wall and the second partition wall are substantially arcuate, and
• wherein a first partition wall first end of the first partition wall is in contact with a first sidewall of the housing, and wherein a second partition wall first end of the second partition wall is in contact with a second sidewall of the housing different than the first sidewall.

A method of promoting mixing of a reductant with an exhaust gas flowing through an aftertreatment system including at least a selective catalytic reduction system, comprising;

• positioning a mixer upstream of the selective catalytic reduction system, the mixer including a housing defining an internal volume, the housing including at least a first passageway, a second passageway, a third passageway and an injection port defined on a sidewall of the housing proximate to the first passageway, the housing including a first partition wall and a second partition wall positioned in the internal volume defined by the housing, the first partition wall and the second partition wall oriented so as to define the first passageway, the second passageway and the third passageway;
• inserting the reductant into the first passageway via the injection port;
• and
• flowing the exhaust gas into the first passageway, the first passageway structured to direct the flow in a first direction towards the second passageway, the second passageway structured to redirect the flow in a second direction substantially opposite the first direction towards the third passageway, and the third passageway structured to redirect the flow in a third direction substantially opposite the second direction towards the selective catalytic reduction system,
• wherein the first partition wall and the second partition wall are substantially arcuate, and wherein a first partition wall first end of the first partition wall is in contact with a first sidewall of the housing, and wherein a second partition wall first end of the second partition wall is in contact with a second sidewall of the housing different than the first sidewall.