US Patent 8033104 Selective catalytic reduction (SCR) catalyst injection systems

A Selective Catalytic Reduction (SCR) injection system for mixing reductant with exhaust gasses. The system includes a plate disposed between walls of an entrance portion and an egress section of the exhaust pipe. The plate intercepts exhaust gasses entering the entrance section of the exhaust pipe and directs such exhaust gasses through apertures in a wall of a reductant-introducing conduit. The conduit has an outlet disposed in the egress section of the exhaust pipe. The wherein dimensions of the apertures in the wall and dimensions in the outlet of the conduit being selected to increase the velocity of the exhaust leaving the outlet of the conduit into the egress section of the exhaust pipe relative to the velocity of the exhaust gases in the entrance section.