METHOD AND ALGORITHM FOR PERFORMING AN NH3 SENSOR RATIONALITY DIAGNOSTIC

摘要

An example method includes interpreting an NH₃ composition value at a position upstream of a selective reduction catalyst (SCR) element fluidly disposed in the exhaust conduit of an engine, interpreting a NO_x composition value at a position downstream of the SCR element, and determining an NH₃ sensor rationality threshold in response to the upstream NH₃ composition value. The method further includes determining an NH₃ sensor health value as indicating a sensor failure in response to the downstream NO_x composition value exceeding the NH₃ sensor rationality threshold.