Authors: Andrew J. Smallbone and Toshiaki Kitagawa

Predictive SI engine combustion models have been developed on the basis of fundamental measurements of the laminar and turbulent burning velocity. The present paper outlines experiments carried out using a spherical fan-stirred combustion vessel operated with initial pressures of up to 0.5MPa. Explosions were carried out using methane-air, propane-air and hydrogen-air mixtures at various equivalence ratios. The influences of increasing pressure on the laminar and turbulent burning velocity are discussed and correlations are presented in terms of a Lewis number (a function of local thermo-diffusion) and Markstein number (derived directly from experiments).