Patent ID: 9546584
Date: 2017-01-17
CPC Classifications: F01N,Y02T

Claim:
1. An exhaust gas after-treatment apparatus for an internal combustion engine, comprising: a first selective catalytic reduction device; a first reductant injecting device positioned upstream from said first selective catalytic reduction device; a second selective catalytic reduction device located downstream from said first selective catalytic reduction device; a second reductant injecting device, which is fluidly connected to said first reductant injecting device, positioned in between said first selective catalytic reduction device and said second selective catalytic reduction device; a mixing device positioned in between said second reductant injecting device and said second catalytic reduction device for creating a uniform exhaust gas; a reductant delivery module including a pressure outlet port fluidly connected to said first reductant injecting device and said second reductant injecting device, and a first reductant-flow control valve for allowing and shutting off a reductant flow passing therethrough fluidly coupling said first reductant injecting device to a reductant tank; and a dosing control unit configured to control said first reductant injecting device to deliver a first dosing quantity of reductant in response to a first dosing rate command, and control said second reductant injecting device to deliver a second dosing quantity of reductant in response to a second dosing rate command.