An exhaust gas aftertreatment device for an internal combustion engine producing the exhaust gas comprises an inlet configured to receive the exhaust gas, an outlet from which the exhaust gas exits the device, an aftertreatment element disposed between the inlet and the outlet, and a flow modification mechanism. The aftertreatment element has a front face receiving the exhaust gas from the inlet of the device, and the flow modification mechanism is configured to modify exhaust gas flow through the aftertreatment element in a manner that maintains uniform temperature across the front face of the element.