It is well known that the spark advance is one of the most important parameters influencing the efficiency of a S.I. 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 (bmep), 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 are 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 TDC as a consequence of both heat exchange between gas and chamber walls and friction losses.

Beccari, A., Beccari, S., Pipitone, E. (2010). An analytical approach for the evaluation of the optimal combustion phase in spark ignition engines. JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER, 132(3), 032802-1-032802-11 [10.1115/1.3155395].

An analytical approach for the evaluation of the optimal combustion phase in spark ignition engines

BECCARI, Alberto;BECCARI, Stefano;PIPITONE, Emiliano
2010-01-01

Abstract

It is well known that the spark advance is one of the most important parameters influencing the efficiency of a S.I. 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 (bmep), 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 are 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 TDC as a consequence of both heat exchange between gas and chamber walls and friction losses.
2010
Settore ING-IND/08 - Macchine A Fluido
Beccari, A., Beccari, S., Pipitone, E. (2010). An analytical approach for the evaluation of the optimal combustion phase in spark ignition engines. JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER, 132(3), 032802-1-032802-11 [10.1115/1.3155395].
File in questo prodotto:
File Dimensione Formato  
pre-print proof.pdf

Solo gestori archvio

Descrizione: copia pre-stampa
Dimensione 350.39 kB
Formato Adobe PDF
350.39 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
final version.pdf

Solo gestori archvio

Dimensione 333.07 kB
Formato Adobe PDF
333.07 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/52681
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 28
  • ???jsp.display-item.citation.isi??? 26
social impact