An experimental and kinetic modeling study of the combustion of n-butane and isobutane in an internal combustion engine
- Union Coll., Schenectady, NY (USA)
Butane is the simplest alkane fuel for which more than a single structural isomer is possible. In the present study, n-butane and isobutane are used in a test engine to examine the importance of molecular structure in determining knock tendency, and the experimental results are interpreted using a detailed chemical kinetic model. A sampling valve was used to extract reacting gases from the combustion chamber of the engine operated in a skip-fire mode. Samples were withdrawn at different times during the skip cycles, providing a measure of the concentrations of a wide variety of reactant, olefin, carbonyl, and other intermediate and product species. The chemical kinetic model predicted the formation of all the intermediate species measured in the experiments. The agreement between the measured and predicted values is mixed and is discussed. Calculations show that RO{sub 2} isomerization reactions are more important contributors to chain branching in n-butane oxidation is dependent on H-atom abstraction reactions involving HO{sub 2} and CH{sub 3}O{sub 2} radicals that occur at higher temperatures than RO{sub 2} 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. 48 refs., 3 figs., 2 tabs.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- DOE/CE
- DOE Contract Number:
- W-7405-ENG-48; AC04-76DP00789; FG04-87AL44658
- OSTI ID:
- 5370309
- Report Number(s):
- UCRL-101594; CONF-8910289-4; ON: DE90002768
- Resource Relation:
- Journal Volume: 1; Conference: Western States Section meeting of the Combustion Institute, Livermore, CA (USA), 23-24 Oct 1989
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
INTERNAL COMBUSTION ENGINES
KINETICS
2-METHYLPROPANE
BUTANE
CHEMICAL REACTIONS
COMBUSTION PROPERTIES
ISOMERIZATION
KNOCK CONTROL
OXIDATION
ALKANES
CONTROL
ENGINES
HEAT ENGINES
HYDROCARBONS
ORGANIC COMPOUNDS
330800* - Emission Control- Alternative Fuels
330100 - Internal Combustion Engines
400800 - Combustion
Pyrolysis
& High-Temperature Chemistry