Third M.I.T. Conference on Computational Fluid and Solid Mechanics June 14–17, 2005  

Thermo-transient and thermo-mechanical finite element modeling of a diesel four-stroke engine piston for variable engine speed conditions

Estela Mari Ricetti Buenoa,b, Miguel Luiz Bucalema,*, Clayton Barcelos Zabeub
aDepartamento de Engenharia de Estruturas e Fundações da Escola Politécnica da Universidade de São Paulo, Av. Prof. Almeida Prado, trav.2 no 83, Cidade Universitária, São Paulo, SP, 05508–900, Brazil bMahle Metal Leve S.A., Technical Center, Mathematical Modeling and Simulation Group, R. Brasilio Luz, 535, Santo Amaro, São Paulo, SP, 04746-901 Brazil

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ABSTRACT
Diesel pistons work with very high temperatures, especially in the region of the bowl rim. Nowadays, with the use of the high speed diesel engines the resulting temperatures are even higher. For these components the thermal loading is extremely important. In general, steady state thermal analyses are used to obtain the temperature distribution of the piston for each engine speed condition and these results are used as boundary conditions for the thermo-mechanical analysis. A substantial amount of experimental observations in engine tests show that important phenomena occur during the transitions of engine speed which may cause considerable damage accumulation. Of course, such phenomena can not be captured by models that consider only steady state boundary conditions. In this work we report the thermo-mechanical modeling of a high speed diesel aluminum alloy piston developing a methodology to model the thermo-transient conditions which allows to obtain the induced stresses that occur when the engine speed changes.

Keywords:  Modeling; Diesel piston; ADINA; Thermo-transient analysis; Variable engine speed conditions; Thermo-mechanical analysis; Thermo-elastic constitutive model; Thermo-elasto-plastic constitutive model

* Corresponding author. E-mail: mlbucale@usp.br