Title: Prediction of friction development during transient diesel engine operation using a detailed model

Authors: C.D. Rakopoulos, E.G. Giakoumis

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

Abstract: An experimentally validated simulation code is used to study the development and contribution of various friction components during turbocharged diesel engine transients. This is accomplished with the use of a recently proposed detailed friction model. Mean friction mean effective pressure modelling is found to considerably underestimate actual friction around firing TDC, leading to lower speed droops for abrupt load increases. The piston rings assembly contribution is dominant for the particular engine, due to its high number of piston rings and its low crankshaft speed. The model can be used to investigate such interesting cases as the effect of engine oil temperature on engine transient response, or the variation of oil film thickness during a cycle or a transient event.

Keywords: bearings; friction mean effective pressure; oil temperature; piston rings; transient operation; turbocharged diesel engines; valve train; simulation; oil film thickness; friction development; modelling; vehicle design.

DOI: 10.1504/IJVD.2007.013223

International Journal of Vehicle Design, 2007 Vol.44 No.1/2, pp.143 - 166

Published online: 12 Apr 2007 *

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