Technical Paper
NOx Model Calibration for BS VI Applications
2019-01-09
2019-26-0050
Challenging limits for NOx in BS VI emission legislation demand high performance conversion techniques. Exhaust after treatment systems such as Lean NOx Trap and selective catalytic reduction can provide effective reduction of Engine out NOx emissions. From the moment of engine start, these systems require reliable signal input of the NOx sensor. The efficient use of such DeNOx systems demands earliest possible activation of the upstream NOx sensor. However, attainment of the sensor dew point delays reliable measurements. Data collected from the emission test cycles, WLTC and NEDC indicates the unavailability of NOx sensor from the beginning of the test cycle. Hence, requirement of a NOx model is inevitable to estimate NOx emissions till sensor reaches its dew point. The scope of this paper is to elucidate the calibration process through which a robust estimation of the NOx emissions can be made in different engine modes along with varying ambient conditions.