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Numberical analysis of the influence of the stroke-to-bore ratio on tumble breakdown
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 12, 1999 by Consiglio Nazionale delle Ricerche in Italy
This paper presents a numerical study on the influence of the stroke-to-bore ratio (S/B) on in cyclinder flow characteristics of four-valve SI engines. The main goal of the present work is to investigate tumble formation and decay mechanisms and its effects on turbulence in four-valve engines characterized by different stroke to bore ratios and different intake port assemblies. Particular attention has been devoted to the S/B effects on flow structures at intake valve closure and mean flow strain rate levels. In particular, this study verifies the effectiveness of tumbling motion as promoter of turbulence and flame propagation enhancer in high performance engines. Comparisons of flow field characteristics of mass production and high performance engine has been performed at own operating conditions too.