Combustion of N-butane and isobutane in an internal combustion engine: A comparison of experimental and modeling results
1991; Elsevier BV; Volume: 23; Issue: 1 Linguagem: Inglês
10.1016/s0082-0784(06)80363-2
ISSN1878-027X
AutoresRichard Wilk, William J. Pitz, Charles K. Westbrook, S. Addagarla, D. L. Miller, Nicholas P. Cernansky, R.M. Green,
Tópico(s)Vehicle emissions and performance
Resumon-Butane and isobutane are used in a test engine to examine the importance of molecular structure in determining knock tendency. The experimental results are interpreted using a detailed chemical kinetic model. Temporally resolved samples were withdrawn from the combustion chamber, providing measured histories of the concentrations of a wide variety of reactant, olefin, carbonyl, and other intermediate and product species. Calculations show that RO2 isomerization reactions are more important contributors to chain branching in the oxidation of n-butane than isobutane. Chain branching in isobutane oxidation is dependent on H-atom abstraction reactions involving HO2 and CH3O2 radicals that occur at higher temperatures than RO2 isomerization reactions. Therefore, an isobutane mixture must be raised to a higher temperature than a n-butane mixture to achieve the same overall rate of reaction.
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