Diesel exhaust fluid mixing

A canister assembly 100 for use in an exhaust gas after-treatment device, comprising (i) a cylindrical shell 102 with a 'top' end 110 and a 'bottom' end 112, (ii) a mixing bowl member 118 attached to the bottom end, symmetrical about the shell's axis 104 and having a mixing bowl pocket 120, and (iii) a flow tube 114 inserted through the top end of the cylindrical shell and terminating short of the mixing bowl member. There may be two diametrically opposed injection points 126, 128 proximate the top end, one for an exhaust gas treatment liquid, such as a diesel exhaust fluid (DEF), the other for charge air to promote mixing. The mixing bowl member reverses the flow direction of exhaust gases, which are led into the annular space between the flow tube and the cylindrical shell, preferably containing an after-treatment device (e.g. DOC, DPF, SCR, AMOx), before being discharged. A canister subassembly is also claimed, comprising a cylindrical shell and a mixing bowl member which further has a flow divider (304, fig. 3), preferably in the form of a conical surface (310, fig. 3) starting from a central peak and terminating at the bottom of the mixing bowl pocket.