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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-483-0

ISBN Online: 978-1-56700-482-3

4th Thermal and Fluids Engineering Conference
April, 14–17, 2019 , Las Vegas, NV, USA


Get access (open in a dialog) pages 1805-1817
DOI: 10.1615/TFEC2019.tta.027505


During operation of an internal combustion engine, in-cylinder temperatures and pressures reaches extremely high values. In a four-stroke engine, this high temperature gas flows through the exhaust valves between exhaust valve opening and exhaust valve closing times. Hence, not only valve head but also other parts of the valve are exposed to high temperature exhaust gas directly. It is critical to obtain temperature distribution across the exhaust valve to detect high temperature regions to check whether temperatures are in valve material's temperature limits or not and also to calculate the life of the valve. Therefore, thermal modeling can be used in design phase while creating valve geometry and/or valve material selection. In this study, transient thermal model of the exhaust valve of a four-stroke, naturally aspirated, 1.6-liter gasoline engine is presented and performed. Preliminarily, estimated in-cylinder temperature and pressure distributions are created as a function of time to calculate in-cylinder heat transfer coefficient by using Woschni correlation. Subdivision of the valve surface is then executed in to define different boundary conditions at different time periods depending on valve’s periodic movement. Transient heat transfer coefficient and temperature boundary conditions are applied to each subdivision using the commercial code FloEFD. Transient simulation is performed until steady-state temperature distribution is obtained on the valve. Numerical results are compared with the thermometric analysis results which are obtained by hardness measurements after the real engine dynamometer test.