Development and Validation of Reaction Mechanisms for Alcohol-Blended Fuels for IC Engine Applications

Abstract

Advanced numerical models have been developed for better understanding of how adding mixed alcohol fuels to stock fuels affects octane number and emissions. For predictions of combustion and emissions, a reduced chemical kinetic mechanism has been developed for fuel mixtures with components including isooctane, n-heptane, methanol, ethanol, n-butanol, and propanol. The model predictions show a boosted octane number with the addition of alcohols and reduced emissions of both carbon monoxide (CO) and nitrogen oxides (NO_x). The numerically predicted trends are consistent with experimental data from the Cooperative Fuel Research (CFR) single-cylinder engine, and the reduced chemistry can be readily implemented into 3-D simulations.

Keywords:

• IC engines
• Mixed alcohols
• Modeling
• Reduced chemistry
• Two-zone model

ACKNOWLEDGMENT

This research is supported by UC Discovery and West Biofuels: Award gcp06-10228, “An Investigation of a Thermochemical Process for the Production of Mixed Alcohol from Biomass.”

Notes

*X _E = volume percentage of ethnaol in fuel mixture, %.

X _G = volume percentage of isooctane in fuel mixture, %.

β_E = β value for enthanol; β_G = β value for isooctane.

*IVO: intake valve open; EVO: exhaust valve open.

^a Chevron baseline gasoline fuel before adding ethanol.

^b Alcohol mixture: ethanol 75%, propanol 11%, butanol 8%, and pentanol 6%by volume.

*A units mole-cm-sec-K, E units cal/mole.