Abstract
Methyl-butanoate is a surrogate for biodiesel fuels. This methyl-ester reaches ignition without remarkable low-temperature oxidation and shows longer ignition delays than n-heptane at low initial temperatures. However, it shows shorter ignition delays than n-heptane or iso-octane at high initial temperatures. The high ignitability of methyl-butanoate was analyzed by the contribution matrices of all elementary reactions to formation of all species and heat release. This fuel has an efficient CH3O formation path via CH3 and direct CH3O formation paths, both characteristic of methyl-esters. The CH3O concentration is extremely high in the ignition preparation period. The rich CH3O decomposes into H and CH2O. Then, H combines with O2 into HO2. This exothermic reaction is activated even immediately after the reaction start, resulting in the short ignition delay
