Knock characteristics of liquid and gaseous fuels in lean mixtures
- Princeton Univ., NJ (United States). Dept. of Mechanical and Aerospace Engineering
- Lawrence Livermore National Lab., CA (United States)
The knock characteristics of natural gas (NG), 89 octane unleaded gasoline, 2,2-dimethyl butane (22DMB), and methyl tert-butyl ether (MTBE) is 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. The computations show that the internal isomerization of alkyperoxy radicals which form much more readily in gasoline and 22DMB than the other fuels, accounts for the effect of equivalence ratio on the ITKL.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- DOE; GRI; USDOE, Washington, DC (United States); Gas Research Inst., Chicago, IL (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5846835
- Report Number(s):
- UCRL-JC-107456; CONF-911025--3; ON: DE92008934
- Country of Publication:
- United States
- Language:
- English
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CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COMBUSTION
CONTROL
ENERGY SOURCES
ENGINES
ETHERS
FLUIDS
FOSSIL FUELS
FUEL GAS
FUEL-AIR RATIO
FUELS
GAS FUELS
GASES
GASOLINE
HEAT ENGINES
INTERNAL COMBUSTION ENGINES
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KNOCK CONTROL
LIQUID FUELS
MATHEMATICAL MODELS
NATURAL GAS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDATION
PETROLEUM PRODUCTS
REACTION KINETICS
THERMOCHEMICAL PROCESSES