Identification of ammonia(NH3)slip is important for accurate closed-loop control and self-adaptation of DeNOx systems.A NH3 slip detection function based on NH3 coverage changing behavior of selective catalytic re-duction(SCR)system under dosing stopped status was proposed based on NOx sensors'cross-sensitivity between NH3 and NOx.Under suitable operating conditions,once the ratio of the DeNOx efficiency calculated by the sensor to that calculated by model was over the calibrated limit,the NH3 slip detection function would be triggered.The NH3 slip could also be detected if the ammonia consumption became over a limit at the time earlier than the DeNOx efficiency below a limit.Validation tests results show that this NH3 slip detection function can effectively detect the NH3 slip of the SCR system,and can immediately send out a NOx slip result when NOx emission exceeds the on-board diagnostics(OBD)limit.
维普
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