Abstract: An engine system includes an internal combustion engine having an exhaust system with an SCR aftertreatment mechanism and a urea injector upstream the aftertreatment mechanism. A mixing mechanism is positioned fluidly between the urea injector and the aftertreatment mechanism and includes a turbulator and a swirler structured to increase mixing of the urea and exhaust gases. Related methodology is also disclosed.

Abstract: A catalyst substrate module for an exhaust aftertreatment system is provided. The catalyst substrate module comprises an outer containment wall, an inner containment wall, a first bar, a second bar, a first substrate element, a second substrate element, and a center member. The outer containment wall and the inner containment wall are co-planar and aligned along a common centerline. The first bar and the second bar are coupled to an inner face of the outer containment wall. The first substrate element is enclosed within an inner face of the inner containment wall and the second substrate element is captured within a space defined by the inner containment wall and the outer containment wall. Further, the center member extends along the centerline of the inner containment.