Diesel Engine Emission Model Transient Cycle Validation

Abstract

A control intended data driven B-spline model for NOx and soot emitted was developed and validated for the 5-cylinder, 2.4-litre Volvo passenger car diesel engine in earlier work. This work extends on the same methodology with some improvements on the model structure for more intuitive calibration and is also developed for the new generation 4-cylinder, 2-litre Volvo passenger car diesel engine. The earlier model was validated using steady state engine measurements and proposed that the model would hold good for transient engine operation. The hypothesis formulated is that a transient engine emission model can be envisioned as a sequence of multi-step steady state engine operation points with minor deviations from the nominal engine operating conditions. The theory is supported by the literature that provides more insight into the transient operation. This idea is carried out in the current work using engine test cell measurements validated for a NEDC as well as a normal road drive cycle that depicts a more transient driving behaviour in comparison to the standard emission driving cycles. Nearly 4600 engine operating points with steady state measurement including nominal and deviant conditions have been used in the development of the model. The ability of the data driven approach to mimic the engine emission generation characteristics during the engine transient operation is analysed and its superior performance in comparison to the Nominal model and the Regression model is demonstrated.