Combustion characteristics of higher-alcohol/gasoline blends

Abstract

An experimental investigation of combustion characteristics of higher-alcohol/gasoline [unleaded test gas 96 (UTG 96)] blends is presented. Lower alcohols (methanol and ethanol) have been used in the past as fuel extenders by mixing them with gasoline, but relatively little work has been reported on higher alcohols (propanol, butanol and pentanol). All these alcohols can be produced from coal-derived syngas. Given the abundant coal reserves in the United States, use of such higher alcohols offers an attractive alternative to alleviate the country's growing needs for transportation fuels.Comparisons of knock limits, indicated mean effective pressure (i.m.e.p.), emissions and fuel characteristics between higher-alcohol/gasoline blends and neat gasoline were made to determine the advantages and disadvantages of blending alcohol with gasoline. All tests were conducted on a singlecylinder Waukesha cooperative fuel research (CFR) engine operating at steady state conditions and stoichiometric air-fuel ratio. The data show that higher-alcohol/gasoline blends have a greater resistance to knock than neat gasoline does, as indicated by the knock resistance indicator (KRI) and the (RONMON)/2 antiknock index (where RON is the research octane number and MON the motor octane number). Ignition delay and combustion interval data show that higher-alcohol/gasoline blends tend to have faster flame speeds.

Laminar Flame Characteristics of C1–C5 Primary Alcohol-Isooctane Blends at Elevated Temperature

“…At all equivalence ratios, with different alcohols added into isooctane, laminar flame speeds increase significantly with the increasing oxygen content. It confirms the conclusion reported by Gautam and Martin [2] that the combustion interval decreases with the increasing oxygen content in the fuel. At ϕ = 0.8 and fixed oxygen content, laminar flame speeds are similar for the blends of isooctane and different alcohols.…”

“…Alcohols, considered a renewable resource, are being extensively investigated in all fields. Unlike traditional fuels, alcohols contain oxygen, which is beneficial for complete combustion and the reduction of toxic emissions [1][2][3][4][5][6][7][8]. Specifically, light alcohols, e.g., methanol and ethanol, have been successfully utilized as octane boosters for traditional fuels.…”

“…Engine tests suggest that oxygen content in the alcohol fuel is relevant to the knocking resistance and the harmful emissions of NO x , soot and carbonyl [2,3,32]. Gautam et al [2,3] investigated the combustion and emission characteristics of a single-cylinder engine fueled with C1-C5 alcohol-gasoline blends. It was concluded that with the increase of oxygen content in the fuel blends, knocking resistance is enhanced, but NO x emissions are increased significantly at high compression ratios.…”

Characterisation of flame development with ethanol, butanol, iso-octane, gasoline and methane in a direct-injection spark-ignition engine

“…Combustion studies with ethanol in SI engines have been carried out by [2][3][4][5][6][7], focusing on performance characteristics, while others [8][9][10][11] have concentrated on engine emission measurements; most of these were done on Port Fuel Injection (PFI) engines. Very few studies have been conducted in latest technology Direct Injection Spark-Ignition (DISI) engines that are typically very sensitive to fuel properties; more to the point, in some of those studies, certain trends illustrate great diversity.…”

Experimental and kinetic modeling study of 1-hexanol combustion in an opposed-flow diffusion flame

“…More recently, the combustion and kinetics of oxidation of a larger alcohol, 1-pentanol, were also studied [22,23] as bio-pentanol production was shown to be possible through the use of some microbial strains [24]. 1-Hexanol, which is the next subsequent alcohol in size, can be blended with conventional fuels or used as a co-solvent for ethanol-diesel fuel mixtures [25].…”