Computational analysis and experimental research into lean mixture combustion in multi-spark plug SI engine

Simulation and experimental research into combustion in multi-spark plug SI engine results are presented in the paper. The outcome of experiment and computational analysis of lean mixtures (excess air number values ? = 1.8) combustion in engine with one, four and seven spark plugs are compared. The results of both the numerical calculations and the experimental research confirmed that applying four spark plugs favourably influences the parameters of lean mixture combustion. The verification of mathematical model applied in KIVA-3V and the real engine was satisfying. The comparison of experimental and numerical research revealed good qualitative conformity of modelled pressure courses with pressure registered on real engine, and in the case of one spark plug the conformity was not only qualitative but also quantitative. The numerical simulations of combustion process reflects the phenomenon occurring in the combustion chamber of the research engine, which is confirmed by the case of seven spark plugs and its negative influence on combustion parameters of both the experimental and the model engines. The measurements results confirm the favourable influence of applying four spark plugs mostly in the case of lean mixture combustion.