Knock characteristics of liquid and gaseous fuels in lean mixtures

Conference · Thu Jun 20 04:00:00 EDT 1991

OSTI ID:10127798

Ronney, P D; Shoda, M; Waida, S T ^[1]; Westbrook, C K; Pitz, W J ^[2]

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1. Princeton Univ., NJ (United States). Dept. of Mechanical and Aerospace Engineering
2. 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: USDOE, Washington, DC (United States); Gas Research Inst., Chicago, IL (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 10127798
• Report Number(s): UCRL-JC--107456; CONF-911025--3; ON: DE92008934
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
025000
33 ADVANCED PROPULSION SYSTEMS
330101
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201
CHEMICAL AND PHYSICOCHEMICAL PROPERTIES
CHEMICAL REACTION KINETICS
COMBUSTION
ETHERS
FUEL-AIR RATIO
GASOLINE
INTERNAL COMBUSTION ENGINES
KNOCK CONTROL
MATHEMATICAL MODELS
NATURAL GAS
SPARK-IGNITION