AMMONIA CROSS-SENSITIVITY ELIMINATIN METHOD OF NOx SENSOR FOR UREA-SCR (SELECTIVE CATALYTIC REDUCTION) SYSTEM

Abstract

This paper reports an ammonia cross-sensitivity elimination filter for SCR systems. Since NOX sensors are cross sensitive to NH3, a reading of NOX sensor could not be accurate. As the reading is inaccurate, the closed-loop SCR systems is unpredictable. The proposed filter can be applied to any kinds of NOX sensors and effectively remove the cross-sensitivity. Single gas and mixed exhaust gas tests are conducted. The results show the evident removal of NH3 in both single gas and mixed gases experiments. The experiments show the filtering method can considerably improve the accuracy of NOX concentration measurement in Urea-SCR systems.