Turbulent Flame Speed of a Gasoline surrogate in conditions representative of modern downsized Spark-Ignition engine

Abstract

The downsized spark ignition (SI) engine is considered as one promising technology to reduce pollutants and greenhouse gas emissions. By boosting the intake air pressure, this operating mode achieves higher efficiency, thus reducing pollutant emissions. Modeling the combustion process in these drastic conditions (high pressure, high temperature and high dilution rate) remains challenging, however, since most of models of premixed turbulent combustion seem insufficiently robust because the turbulent combustion regime might be out of the classical flamelet regime. Two different setups, a spherical vessel and a one-shot engine, were used to study turbulence-flame interaction in conditions representative of a modern downsized SI engine, i.e. under high pressure, high temperature and high dilution and controlled turbulence. Turbulent flame speed were measured in a wide range of Damkohler and Karlovitz number. Several turbulent flame speed correlations from the literature are also tested and compared to the complete experimental dataset gathered on both setups.