AMMONIA SENSOR CONTROL OF AN SCR AFTERTREATMENT SYSTEM

摘要

A system includes an engine, an exhaust conduit for the engine, a first SCR catalyst fluidly coupled to the exhaust conduit, and a second SCR catalyst fluidly coupled to the exhaust conduit at a position downstream of the first SCR catalyst. The system further includes an ammonia sensor positioned between the first and second SCR catalysts. A reductant doser is positioned upstream of the first SCR catalyst. The system includes a controller that determines an amount of NH3 present from the NH3 sensor, and computes an actuator response function from at least one operating condition of the first SCR catalyst. The actuator response function includes a reductant injector response as a function of the amount of NH3, and the actuator response function includes a response discontinuity. The controller further determines a reductant injection amount from the amount of NH3 and the actuator response function, and provides a reductant injector command.