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An analytical approach for the evaluation of the optimal combustion phase in spark ignition engines / A. Beccari in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 3 (Mars 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 3 (Mars 2010) . - 11 p. Titre : An analytical approach for the evaluation of the optimal combustion phase in spark ignition engines Type de document : texte imprimé Auteurs : A. Beccari, Auteur ; S. Beccari, Auteur ; E. Pipitone, Auteur Année de publication : 2010 Article en page(s) : 11 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Friction  Heat  transfer  Internal  combustion  engines  Pistons  Sparks Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : It is well known that the spark advance is one of the most important parameters influencing the efficiency of a spark ignition engine. A change in this parameter causes a shift in the combustion phase, whose optimal position, with respect to the piston motion, implies the maximum brake mean effective pressure for given operative conditions. The best spark timing is usually estimated by means of experimental trials on the engine test bed or by means of thermodynamic simulations of the engine cycle. In this work, instead, the authors developed, under some simplifying hypothesis, an original theoretical formulation for the estimation of the optimal combustion phase. The most significant parameters involved with the combustion phase are taken into consideration; in particular, the influence of the combustion duration, of the heat release law, of the heat transfer to the combustion chamber walls, and of the mechanical friction losses is evaluated. The theoretical conclusion, experimentally proven by many authors, is that the central point of the combustion phase (known as the location of the 50% of mass fraction burnt, here called MFB50) must be delayed with respect to the top dead center as a consequence of both heat exchange between gas and chamber walls and friction losses. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000003 [...] [article] An analytical approach for the evaluation of the optimal combustion phase in spark ignition engines [texte imprimé] / A. Beccari, Auteur ; S. Beccari, Auteur ; E. Pipitone, Auteur . - 2010 . - 11 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 3 (Mars 2010) . - 11 p. Mots-clés : Friction  Heat  transfer  Internal  combustion  engines  Pistons  Sparks Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : It is well known that the spark advance is one of the most important parameters influencing the efficiency of a spark ignition engine. A change in this parameter causes a shift in the combustion phase, whose optimal position, with respect to the piston motion, implies the maximum brake mean effective pressure for given operative conditions. The best spark timing is usually estimated by means of experimental trials on the engine test bed or by means of thermodynamic simulations of the engine cycle. In this work, instead, the authors developed, under some simplifying hypothesis, an original theoretical formulation for the estimation of the optimal combustion phase. The most significant parameters involved with the combustion phase are taken into consideration; in particular, the influence of the combustion duration, of the heat release law, of the heat transfer to the combustion chamber walls, and of the mechanical friction losses is evaluated. The theoretical conclusion, experimentally proven by many authors, is that the central point of the combustion phase (known as the location of the 50% of mass fraction burnt, here called MFB50) must be delayed with respect to the top dead center as a consequence of both heat exchange between gas and chamber walls and friction losses. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000003 [...]