In order to improve fuel conversion efficiency, currently made spark-ignited engines are characterized by the adoption of gasoline direct injection, supercharging and/or turbocharging, complex variable valve actuation strategies. The resulting increase in power/size ratios is responsible for substantially higher average thermal loads on the engine components, which in turn result in increased risks of both thermo-mechanical failures and abnormal combustion events such as surface ignition or knock. The paper presents a comprehensive numerical methodology for the accurate estimation of knock tendency of SI engines, based on the integration of different modeling frameworks and tools. Full-cycle in-cylinder analyses are used to estimate the point-wise heat flux acting on the engine components facing the combustion chamber. The resulting cycle-averaged heat fluxes are then used in a conjugate heat transfer model of the whole engine in order to reconstruct the actual point-wise temperature distribution of the combustion chamber walls. The two simulation realms iteratively exchange information until convergence is met. Particularly, the effect of point-wise temperature distribution on the onset of abnormal combustion events is evaluated. In-cylinder analyses account for the actual autoignition behavior of the air/fuel mixture through a look-up table approach: the combustion chamber is treated as a two-zone region (burnt/unburnt), where ignition delay tabulation, generated off-line using a constant pressure reactor, is applied to the unburnt region to estimate cell-wise knock proximity. The methodology is applied to a high performance engine and the importance of an accurate representation of the combustion chamber thermal boundary conditions when aiming at precisely evaluating the surface ignition/knock tendency is highlighted.

Integrated In-Cylinder/CHT Analysis for the Prediction of Abnormal Combustion Occurrence in Gasoline Engines / Fontanesi, Stefano; Cicalese, Giuseppe; Cantore, Giuseppe; D'Adamo, Alessandro. - In: SAE TECHNICAL PAPER. - ISSN 0148-7191. - ELETTRONICO. - 1:(2014). (Intervento presentato al convegno SAE 2014 World Congress and Exhibition tenutosi a Detroit nel 2014) [10.4271/2014-01-1151].

Integrated In-Cylinder/CHT Analysis for the Prediction of Abnormal Combustion Occurrence in Gasoline Engines

FONTANESI, Stefano;CICALESE, Giuseppe;CANTORE, Giuseppe;d'ADAMO, Alessandro
2014

Abstract

In order to improve fuel conversion efficiency, currently made spark-ignited engines are characterized by the adoption of gasoline direct injection, supercharging and/or turbocharging, complex variable valve actuation strategies. The resulting increase in power/size ratios is responsible for substantially higher average thermal loads on the engine components, which in turn result in increased risks of both thermo-mechanical failures and abnormal combustion events such as surface ignition or knock. The paper presents a comprehensive numerical methodology for the accurate estimation of knock tendency of SI engines, based on the integration of different modeling frameworks and tools. Full-cycle in-cylinder analyses are used to estimate the point-wise heat flux acting on the engine components facing the combustion chamber. The resulting cycle-averaged heat fluxes are then used in a conjugate heat transfer model of the whole engine in order to reconstruct the actual point-wise temperature distribution of the combustion chamber walls. The two simulation realms iteratively exchange information until convergence is met. Particularly, the effect of point-wise temperature distribution on the onset of abnormal combustion events is evaluated. In-cylinder analyses account for the actual autoignition behavior of the air/fuel mixture through a look-up table approach: the combustion chamber is treated as a two-zone region (burnt/unburnt), where ignition delay tabulation, generated off-line using a constant pressure reactor, is applied to the unburnt region to estimate cell-wise knock proximity. The methodology is applied to a high performance engine and the importance of an accurate representation of the combustion chamber thermal boundary conditions when aiming at precisely evaluating the surface ignition/knock tendency is highlighted.
2014
SAE 2014 World Congress and Exhibition
Detroit
2014
1
Fontanesi, Stefano; Cicalese, Giuseppe; Cantore, Giuseppe; D'Adamo, Alessandro
Integrated In-Cylinder/CHT Analysis for the Prediction of Abnormal Combustion Occurrence in Gasoline Engines / Fontanesi, Stefano; Cicalese, Giuseppe; Cantore, Giuseppe; D'Adamo, Alessandro. - In: SAE TECHNICAL PAPER. - ISSN 0148-7191. - ELETTRONICO. - 1:(2014). (Intervento presentato al convegno SAE 2014 World Congress and Exhibition tenutosi a Detroit nel 2014) [10.4271/2014-01-1151].
File in questo prodotto:
File Dimensione Formato  
2014-01-1151_FINAL.pdf

Accesso riservato

Descrizione: Post print final
Tipologia: Versione dell'autore revisionata e accettata per la pubblicazione
Dimensione 1.45 MB
Formato Adobe PDF
1.45 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Licenza Creative Commons
I metadati presenti in IRIS UNIMORE sono rilasciati con licenza Creative Commons CC0 1.0 Universal, mentre i file delle pubblicazioni sono rilasciati con licenza Attribuzione 4.0 Internazionale (CC BY 4.0), salvo diversa indicazione.
In caso di violazione di copyright, contattare Supporto Iris

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11380/1072668
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 30
  • ???jsp.display-item.citation.isi??? ND
social impact