Several models for the evaluation of Gross Heat Release from the internal combustion engine (ICE) areoften used in literature. One of these is the First Law − Single Zone Model (FL−SZM), derived from the First Law ofThermodynamics. This model presents a twice advantage: first it describes with accuracy the physic of the phenomenon(charge heat release during the combustion stroke and heat exchange between gas and cylinder wall); second it has a greatsimplicity in the mathematical formulation. The evaluation of Heat Release with the FL−SZM is based on pressureexperimental measurements inside the cylinder, and on the assumption of several parameters as the specific heat ratio, walltemperature, polytropic exponent for the motored cycle evaluation, and many others. In this paper the influence of gasesthermodynamic properties on Gross Heat Release has been esteemed. In particular the influence of an appropriate equationfor k = k(T) (specific heat ratio vs. temperature) which describes the variations of gases thermodynamic properties with themean temperature inside the cylinder has been evaluated. This equation has been calculated by new V order LogarithmicPolynomials (VoLP), fitting experimental gases properties through the least square methods.

ICE Gross Heat Release Strongly Influenced by Specific Heat Ratio Values

LANZAFAME, Rosario;MESSINA, Michele
2003-01-01

Abstract

Several models for the evaluation of Gross Heat Release from the internal combustion engine (ICE) areoften used in literature. One of these is the First Law − Single Zone Model (FL−SZM), derived from the First Law ofThermodynamics. This model presents a twice advantage: first it describes with accuracy the physic of the phenomenon(charge heat release during the combustion stroke and heat exchange between gas and cylinder wall); second it has a greatsimplicity in the mathematical formulation. The evaluation of Heat Release with the FL−SZM is based on pressureexperimental measurements inside the cylinder, and on the assumption of several parameters as the specific heat ratio, walltemperature, polytropic exponent for the motored cycle evaluation, and many others. In this paper the influence of gasesthermodynamic properties on Gross Heat Release has been esteemed. In particular the influence of an appropriate equationfor k = k(T) (specific heat ratio vs. temperature) which describes the variations of gases thermodynamic properties with themean temperature inside the cylinder has been evaluated. This equation has been calculated by new V order LogarithmicPolynomials (VoLP), fitting experimental gases properties through the least square methods.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/408
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