Emissions characteristics of higher alcohol/gasoline blends

Abstract

An experimental investigation was conducted to determine the emissions characteristics of higher alcohols and gasoline (UTG96) blends. While lower alcohols (methanol and ethanol) have been used in blends with gasoline, very little work has been done or reported on higher alcohols (propanol, butanol and pentanol). Comparisons of emissions and fuel characteristics between higher alcohol/gasoline blends and neat gasoline were made to determine the advantages and disadvantages of blending higher alcohols with gasoline. All tests were conducted on a single-cylinder Waukesha Cooperative Fuel Research engine operating at steady state conditions and stoichiometric air-fuel (A/F) ratio. Emissions tests were conducted at the optimum spark timing-knock limiting compression ratio combination for the particular blend being tested. The cycle emissions [mass per unit time (g/h)] of CO, CO2 and organic matter hydrocarbon equivalent (OMHCE) from the higher alcohol/gasoline blends were very similar to those from neat gasoline. Cycle emissions of NOx from the blends were higher than those from neat gasoline. However, for all the emissions species considered, the brake specific emissions (g/kW h) were significantly lower for the higher alcohol/gasoline blends than for neat gasoline. This was because the blends had greater resistance to knock and allowed higher compression ratios, which increased engine power output. The contribution of alcohols and aldehydes to the overall OMHCE emissions was found to be minimal. Cycle fuel consumption (g/h) of higher alcohol/gasoline blends was slightly higher than with neat gasoline due to the lower stoichiometric A/F ratios required by the blends. However, the brake specific fuel consumption (g/kW h) for the blends was significantly lower than that for neat gasoline.

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.…”

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

“…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.…”

Performance and Emission Characteristics of Spark Ignition Engine Fuelled with Ethanol and Methanol Gasoline Blended Fuels

“…Chao et al (2000) indicated that using ethanol gasoline blended fuels increases the emission of formaldehyde, acetaldehyde and acetone several times than those from gasoline. Gautam et al (2000) investigated the emissions characteristics between higher alcohol/gasoline blends and neat gasoline. It was found that the cycle emissions of CO, CO 2 and organic matter hydrocarbon equivalent from the higher alcohol/gasoline blends were very similar to those from neat gasoline.…”