Autoignition behavior of lean mixtures: Chemical and thermodynamics effects

Conference · Tue Jan 14 23:00:00 EST 1992

OSTI ID:5433745

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)

Knock characteristics of natural gas (NG), 89 octane unleaded gasoline, 2,2-dimethyl butane (22DMB), and methyl tert-butyl ether (MTBE) in stoichiometric and lean fuel-air mixtures were studied in a production 4-cylinder automotive engine. The Intake Temperature at the Knock Limit (ITKL) was different for each fuel but always higher in lean mixtures. Gasoline and 22DMB exhibited much greater increases in ITKL than MTBE and NG at lean conditions. Surprisingly, for lean mixtures 22DMB exhibited higher ITKL than MTBE and was almost as high as NG. Comparison with detailed numerical modelling was very favorable. Computations show that both differences in chemistry and end-gas temperature and pressure histories are responsible for these trends. This behavior is interpreted in terms of the Negative Temperature Coefficient behavior of hydrocarbon oxidation. The implication of these results for the specification of optimal fuels for lean-burn engine is discussed.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5433745
• Report Number(s): UCRL-JC-109673; CONF-920707--24; ON: DE92009690
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
330101* -- Internal Combustion Engines-- Spark-Ignition
330800 -- Emission Control-- Alternative Fuels
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201 -- Chemical & Physicochemical Properties
ALKANES
AUTOMOTIVE FUELS
BUTANE
CHEMICAL REACTION KINETICS
CONTROL
EFFICIENCY
ENERGY SOURCES
ENGINES
ETHERS
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
GASOLINE
HEAT ENGINES
HYDROCARBONS
IGNITION
INTERNAL COMBUSTION ENGINES
KINETICS
KNOCK CONTROL
LIQUID FUELS
MATHEMATICAL MODELS
NATURAL GAS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PETROLEUM PRODUCTS
REACTION KINETICS
SPARK IGNITION ENGINES
TEMPERATURE DEPENDENCE
TESTING