Title: Exhaust emissions estimation during transient turbocharged diesel engine operation using a two-zone combustion model

Authors: C.D. Rakopoulos, A.M. Dimaratos, E.G. Giakoumis, D.C. Rakopoulos

Addresses: Internal Combustion Engines Laboratory, Thermal Engineering Department, School of Mechanical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus 15780, Athens, Greece. ' Internal Combustion Engines Laboratory, Thermal Engineering Department, School of Mechanical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus 15780, Athens, Greece. ' Internal Combustion Engines Laboratory, Thermal Engineering Department, School of Mechanical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus 15780, Athens, Greece. ' Internal Combustion Engines Laboratory, Thermal Engineering Department, School of Mechanical Engineering, National Technical University of Athens, 9 Heroon Polytechniou Street, Zografou Campus 15780, Athens, Greece

Abstract: A comprehensive, two-zone, transient, diesel combustion model is used to study the performance and exhaust emissions of a turbocharged diesel engine during load transients. Analytical modelling of fuel spray and in-cylinder processes is included, while detailed equations concerning all engine sub-systems describe the phenomena, which diversify transient operation from the steady-state. Demonstrative diagrams are provided for the time histories of nitric oxide (NO) and soot emissions during transient operation, and the main factors affecting their formation are highlighted. Moreover, in-cylinder development of NO concentration and soot density during individual transient cycles is provided and compared with their respective steady-state counterparts. This comparison points out the differences between steady-state and transient operation, as regards exhaust emissions development. The study is expanded with the investigation of load change magnitude and cylinder wall insulation effects on transient emissions.

Keywords: exhaust emissions; insulation; nitric oxide emissions; NO concentration; soot density; transient operation; turbocharged diesel engines; two-zone modelling; combustion modelling; soot emissions.

DOI: 10.1504/IJVD.2009.024244

International Journal of Vehicle Design, 2009 Vol.49 No.1/2/3, pp.125 - 149

Available online: 30 Mar 2009 *

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