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A detailed chemical kinetic mechanism was used to simulate the oxidation of 1-butene, 2-butene, and isobutene under motored engine conditions. Predicted species concentrations were compared to measured species concentrations obtained from a motored, single-cylinder engine. The chemical kinetic model reproduced correctly the trends in the measured species concentrations. The computational and experimental results showed the main features of olefin chemistry: radical addition to the bond leads to the production of the observed carbonyls and epoxides. For isobutene oxidation, the production of unreactive, 2-methyl allyl radicals leads to higher molecular-weight species and chain termination.

The knock characteristics of natural gas (NG), 89 octane unleaded gasoline, 2,2-dimethyl butane (22DMB), and methyl tert-butyl ether (MTBE) in stoichiometric and lean fuel-air mixtures were studied in a production 4-cylinder automotive engine. The Intake Temperature at the Knock Limit (ITKL) was found to be very different for each fuel but in every case the ITKL of lean mixtures was much higher than that of a stoichiometric mixture. Gasoline and 22DMB exhibited a much greater increase in ITKL than MTBE and NG at lean conditions. Surprisingly, for lean mixtures 22DMB exhibited values of ITKL that were much higher than MTBE and almost as high as those of NG. These results are compared with a detailed numerical model of autoignition chemistry. Good agreement between model and experiment is found for all modelled conditions.