Heat transfer in premixed spark ignition engines part II: Systematic analysis of the heat transfer phenomena

The heat transfer is a keystone sub-model for engine simulation tools since it affects all targeting parameters (power output, efficiency and emissions. Part I of this work [1] reported a thorough review of heat transfer measurements from literature. Using Design of Experiments (DoE) two measurement matrices were constructed, one for motored and one for fired operation. The present paper focuses on the measurements under fired operation and analyses the heat transfer phenomena in a systematic way. First, the effect of the dependent engine settings on the heat flux is analyzed in a consistent way using ANOVA (Analysis of Variance). Second, it also discusses the influence of the gas properties on the heat flux, which has been overlooked by many authors. Third, the validity of the Reynolds analogy modelling approach is checked, and several improvements are proposed.