Prediction of Soot and NOx Emissions for Common Rail Diesel Engines Operating Under Transient Conditions

Abstract

Due to stricter emission norms, diesel engine is facing challenges of in-cylinder emissions reduction especially in transient operating conditions. Low complexity emission prediction models are desired, with an objective to extend it to emissions prediction during transient operations. This paper is focused on the formulation and investigation of simplified model for prediction of in-cylinder pressures, temperatures, engine-out NOx and Soot emissions. Being a predictive model, this model does not require cylinder pressure as an input to predict heat release. To have better computational efficiency, single-zone model is used for the combustion prediction. Fuel burning rate is predicted with Watson model. Watson model is modified to improve its predictability over complete bmep range for the selected high bmep engine. Two-zone model has been formulated to predict NOx and Soot emissions. Flame temperatures are predicted by enthalpy balance. Thermal NO concentration is predicted by using Zeldovich mechanism. Soot prediction is based on approach proposed by Hiroyasu. Prediction model is calibrated using a Turbocharged DI Common rail Diesel engine, at various speed-load conditions. Using this calibrated model, NOx and Soot emissions are predicted on a part of ETC cycle. It is observed that the model predicts NOx emissions and soot emission trends with reasonable accuracy and this model can be used for emissions prediction on a transient cycle.
Copyright © 2014 Praise Worthy Prize - All rights reserved.