Ignition quality and composition of fuel volatile fraction: Effects on diesel combustion
An experimental study was conducted to discern the nature of the mixture formation process in high and low swirl direct injection diesel engines. The study focussed on the order of fuel component vaporization and burning. The principal parameters varied were ignition quality and aromatics content of the fuel volatile fraction, and swirl ratio. The effect of fuel sulfur-bearing component volatility on exhaust smoke was investigated. One fuel set was blended to have smooth boiling curves and bulk properties like typical D-2 fuels, but with modification of volatile fraction ignition quality and aromatics content. The second set had a radically changed volatile fraction ignition quality. This set consisted of D-2 fuels blended with n-octane, a volatile, high ignition quality hydrocarbon. These fuels did not have smooth boiling curves. The sulfur study used a D-2 fuel doped with two sulfur-bearing hydrocarbons of different volatilities. The experimental data included cylinder pressure, gaseous emissions, and smoke; it showed that ignition delay and emissions were insensitive to the fuel volatile fraction changes of the smooth boiling fuels in both engines. The low swirl engine was relatively insensitive to the changes of the n-octane blends. The ignition delays of the smooth boiling fuels correlated well with cetane number. This was not always true for the n-octane blends. Comparisons of smoke for the sulfur-doped fuels in the low swirl engine showed that fuel sulfur does change smoke. The more volatile dopant changed smoke more. The bulk fuel cetane number is a valid indicator of ignition quality for the smooth boiling fuels set. The volatile fraction ignition quality is not disproportionately significant. Mixture formation was found not to be governed by fuel volatility.
- Research Organization:
- Wisconsin Univ., Madison, WI (USA)
- OSTI ID:
- 5805097
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
023000 -- Petroleum-- Properties & Composition
025000* -- Petroleum-- Combustion
33 ADVANCED PROPULSION SYSTEMS
330102 -- Internal Combustion Engines-- Diesel
AEROSOLS
ALKANES
ANTIKNOCK RATINGS
AROMATICS
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
COLLOIDS
COMBUSTION KINETICS
CYLINDERS
DIESEL ENGINES
DIESEL FUELS
DISPERSIONS
EMISSION
ENGINES
EVAPORATION
EXHAUST GASES
FLUID FLOW
FLUIDS
FUEL INJECTION SYSTEMS
FUEL SYSTEMS
GASEOUS WASTES
GASES
HEAT ENGINES
HYDROCARBONS
IGNITION
INTERNAL COMBUSTION ENGINES
KINETICS
MATTER
MIXTURES
OCTANE
ORGANIC COMPOUNDS
PERFORMANCE
PETROLEUM PRODUCTS
PHASE TRANSFORMATIONS
PRESSURE MEASUREMENT
REACTION KINETICS
RESIDUES
SMOKES
SOLS
SULFUR CONTENT
VOLATILE MATTER
VORTEX FLOW
WASTES