Patent ID: 8109077

Claim:
A system for controlling diesel emissions with two or more reagent injectors, comprising: a first injector for injecting a first reagent into an exhaust stream from a diesel engine, wherein said first injector is positioned upstream of at least one of a diesel particulate filter and a lean NOx trap; a second injector for injecting a second reagent into the exhaust stream, wherein said second injector is positioned downstream of said first injector and upstream of a selective catalytic reduction catalyst, and wherein the second reagent is different from the first reagent; a first pump for providing the first reagent to said first injector; a first tank connected to the first pump and comprising the first reagent; a second pump for providing the second reagent to said second injector; a second tank connected to the second pump and comprising the second reagent; and a control unit for controlling the injection of both the first reagent and the second reagent; wherein said control unit is adapted to receive an alert signal indicative of the second tank reaching a predetermined low level; and wherein said control unit transmits at least one control signal to stop the injecting of the second reagent and to begin injecting the first reagent upon receiving the alert signal.