Title: Irreversibility production during transient operation of a turbocharged diesel engine

Authors: Evangelos G. Giakoumis, Eleftherios C. Andritsakis

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

Abstract: A computer model has been developed for studying the first- and second-law balances of a turbocharged diesel engine under transient conditions. Special attention is paid to the identification and quantification of the irreversibilities of all processes and devices after a ramp increase in load. The model includes a detailed analysis of mechanical friction, a separate consideration for the processes in each cylinder during a cycle (|multi-cylinder| model) and a mathematical simulation of the fuel pump. Experimental data taken from a turbocharged diesel engine are used for the evaluation of the model|s predictive capabilities. The contribution of combustion, anifolds, aftercooler and turbocharger irreversibility production is analysed using detailed diagrams. It is revealed that transient in-cylinder irreversibilities develop in a different manner compared to the respective steady-state. Combustion has always a dominant contribution but the exhaust manifold irreversibilities cannot be ignored, whereas those attributed to the inlet manifold, turbocharger and aftercooler are always of lesser importance.

Keywords: turbocharged diesel engines; transient operation; second law of thermodynamics; exergy; availability; irreversibilities; combustion; vehicle design.

DOI: 10.1504/IJVD.2007.013674

International Journal of Vehicle Design, 2007 Vol.45 No.1/2, pp.128 - 149

Published online: 11 May 2007 *

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