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CI engine as a case study of thermomechanical FE analysis of the piston - piston rings - cylinder system

Szurgott P., Niezgoda T.

Journal of KONES

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2012

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Vol. 19, No. 1

399-406

EN

The compression-ignition engine as a case study of a methodology of the numerical modelling and simulation of the piston - piston rings - cylinder system was presented in the paper. Thermomechanical FE analysis, taking into account thermal and mechanical loads, was carried out using the MSC.Marc/Mentat software. The mechanical loads included loads due to inertial and gas forces as well. A three dimensional solid geometrical model of the considered set was developed using AutoCAD software, whereas the finite element mesh was generated using Altair HyperMesh. Kinematic boundary conditions - the vertical displacement and acceleration of the piston - were described by the corresponding curves as a function of time for selected engine speed. Changes in pressure on the piston crown were estimated based on data from the engine manufacturer and the corresponded indicator diagram available in the literature. The results of thermomechanical FE analysis were presented in the form of stress and/or displacement contours. The main aim of the analysis was to determine the deformation of the piston depending of on the piston material. Two types of material were compared - the actual one PA12 aluminum alloy and the new composite material with low hysteresis. The second material was characterized by slight differences of the coefficient of thermal expansion for heating and cooling.

2

Thermomechanical FE analysis of the engine piston made of composite material with low histeresis

Szurgott P., Niezgoda T.

Journal of KONES

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2011

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Vol. 18, No. 1

645-650

EN

The main purpose of the preliminary analyses presented in the paper was to compare the behaviour of the combustion engine piston made of different type of materials under thermal load. A thermomechanical FE analysis of the engine piston made of composite material was shown. A selected engine is installed in one of the popular polish tanks. The proposed new material is characterized by a low hysteresis – the differences of the coefficient of thermal expansion for heating and cooling are not significant. The results obtained for the piston made of a new material were compared with those for the current standard material. The piston was loaded by a temperature field inside it. Appropriate averaged thermal boundary conditions such as temperatures and heat fluxes were set on different surfaces of the FE model. FE analyses were carried out using MSC.Marc software. Development of the FE model was also presented. Geometrical CAD model of the piston was developed based on the actual engine piston, which was scanned using a 3D laser scanner. A cloud of points obtained from the scanner was processed and converted into a 3- dimensional solid model. FE model of a quarter part of the piston was developed for the preliminary analysis presented in the paper. 4-node tetrahedron finite elements were applied since there was no axial symmetry of the considered object. The temperature field inside the piston was determined and presented in the form of contour bands. Contours of displacement and stress in a radial direction were shown as well.

3

Die-cast heterophase composites with AlSi13Mg1CuNi matrix

Dyzia M., Dolata-Grosz A., Wieczorek J., Śleziona J.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1 spec.

301--304

EN

On the basis of the performed tests, an advantageous interaction of glassy carbon particles in a couple consisting of a heterophase composite and a spheroidal cast iron has been corroborated. It was found that, the presence of glassy carbon in the heterophase composite (SiC+C) affects the stabilization of the friction coefficient value as a function of the friction distance and reduces the intensity of the wearing-in stage of the interacting surfaces. Both a decrease of the friction coefficient and the wear of the heterophase composites may be connected with the carbon particles' chipping effect and the deposition of its fragments on the surface of the interacting components of the friction couple, which forms a kind of a solid lubricating agent in the system. This should allow applying of this material to the composite piston-cylinder sleeve system in piston air-compressors. Further works will concern the selection of the matrix alloy composition with the purpose of reducing the phenomenon of particles chipping during machining. It seems that one of the possibilities is the application of a more plastic matrix and optimizing the fraction of reinforcing phases and their gradient distribution in the casting.