Combustion Characteristics Of Ethanol Research Articles

Analysis of Combustion and Cycle to Cycle Variations of an Ethanol (E100) Fueled Spark-Ignition Engine

Ethanol, produced from biomass, is a renewable fuel that can be an attractive alternative fuel to gasoline for the increasing concerns of energy security and the environment. In the present work, combustion characteristics of ethanol (E100) fueled spark-ignition engine are compared with base gasoline fuel, and consecutively evaluated the cycle-to-cycle variations (CCV) of the engine parameters using statistical analysis. These investigations were performed on a 250cc air-cooled four-stroke single-cylinder port-fuel injection spark-ignition fueled with ethanol and gasoline fuels. The engine was operated at 3500 rpm and 4000 rpm of engine speed while maintaining the same loads for ethanol and gasoline. It was found from the results that the peak in-cylinder pressure (Ppeak) is lower with ethanol than gasoline at a given load. The Ppeak decreased from 27.5 to 25.5 bar when ethanol was used in the engine at 9.8:1 compression ratio, 3500 rpm, and 5 Nm load. Moreover, the mass fraction burned of the air-fuel mixture was faster for ethanol as compared to gasoline. The CCV with Ppeak, location of Ppeak, engine speed, and indicated mean effective pressure (IMEP) were evaluated. The result showed that CCV of Ppeak and its location were lowered for ethanol related to gasoline. A decrement in the coefficient of variation (COV) of Ppeak and its location from 11.6% to 8.3% and 12.6% to 11.7%, respectively, were observed when ethanol was utilized in the engine instead of gasoline at 3500 rpm and 5 Nm load. This resulted in a decrease in the COV of IMEP and engine speed by 2.8% and 0.25%, respectively, for ethanol as compared to gasoline at 3500 rpm and 5 Nm. This study results indicate the combustion stability of spark ignition engine with ethanol (E100) is better than gasoline fuel.

Theoretical Study on Reactions of α-Site Hydroxyethyl and Hydroxypropyl Radicals with O2.

α-Site alcohol radicals are the most important products of H-abstract reactions from alcohols since the hydroxyl moiety weakens the α-site C-H bond. Reactions between α-site alcohol radicals and O2 play an important role in combustion of alcohols, especially at relatively low temperatures. However, reliable reaction pathways and rate constants for these reactions are still lacking. Theoretical studies on reactions in α-hydroxyethyl radical (CH3C•HOH) + O2 and α-hydroxypropyl radical (C2H5C•HOH and CH3C•OHCH3) + O2 reaction systems are performed in this work. Pressure-dependent rate constants for the involved reactions in a wide range of temperatures are determined using the Rice-Ramsperger-Kassel-Marcus/master equation (RRKM/ME) method. Our results show that rate constants for reactions in the α-hydroxypropyl radical + O2 system are quite different from those in the CH3C•HOH + O2 system. Detailed reaction pathways for these reaction systems are clarified, although combustion characteristics of ethanol and propanol do not change much with the obtained rate constants for these reactions. Important reaction channels in producing enols, especially in the combustion of propanol, are also provided. The obtained rate constants for these reactions over a wide range of temperatures and pressures are helpful in developing combustion mechanisms for ethanol and propanol.

Effects of direct-current electric fields on flame shape and combustion characteristics of ethanol in small scale

The aim of this work is to investigate the effects of direct-current electric fields on the behavior of the small-scale diffusion ethanol flame. The flow rate of liquid ethanol, the flame temperatures, and the flame shapes were measured. The results showed that the stable working ranges of a small-scale combustor became narrower under the direct-current electric field. The main reason was that the evaporation velocity of liquid ethanol limited by great heat loss effect cannot keep up with the increasing of combustion velocity by the ionic wind effect. The movements of those charged particles in flame enhanced the combustion process, resulting in higher flame temperatures under positive or negative direct-current electric field. The flame heights decreased with increasing applied voltages, due to the ionic wind effect increasing the flame temperature and the diffusivity. The flame voltage–current characteristic was also examined. Three regions can be divided: the subsaturation region, the saturation region, and the supersaturation region. Finally, the ratios of electric active power to actual burning thermal power of ethanol flame were calculated. It can be inferred that using the external direct-current electric field with little power consumption to control combustion and flame is a feasible method.

A Comparison of the Microbial Production and Combustion Characteristics of Three Alcohol Biofuels: Ethanol, 1-Butanol, and 1-Octanol.

Over the last decade, microbes have been engineered for the manufacture of a variety of biofuels. Saturated linear-chain alcohols have great potential as transport biofuels. Their hydrocarbon backbones, as well as oxygenated content, confer combustive properties that make it suitable for use in internal combustion engines. Herein, we compared the microbial production and combustion characteristics of ethanol, 1-butanol, and 1-octanol. In terms of productivity and efficiency, current microbial platforms favor the production of ethanol. From a combustion standpoint, the most suitable fuel for spark-ignition engines would be ethanol, while for compression-ignition engines it would be 1-octanol. However, any general conclusions drawn at this stage regarding the most superior biofuel would be premature, as there are still many areas that need to be addressed, such as large-scale purification and pipeline compatibility. So far, the difficulties in developing and optimizing microbial platforms for fuel production, particularly for newer fuel candidates, stem from our poor understanding of the myriad biological factors underpinning them. A great deal of attention therefore needs to be given to the fundamental mechanisms that govern biological processes. Additionally, research needs to be undertaken across a wide range of disciplines to overcome issues of sustainability and commercial viability.

Combustion Characteristics of Ethanol and PRF Laminar Flames

In this study, laminar burning velocities of ethanol, iso-octane and n-heptane-air mixtures were determined experimentally over a wide range of equivalence ratio under the various pressures up to 0.5MPa, employing spherically expanding flames. Considering non-linear extrapolations, the effects of stretch was minimized by extrapolating the reference flame speed to vanishing stretch. The laminar burning velocities of iso-octane were found to be lower than those of ethanol and n-heptane throughout the range of experimental equivalence ratios. For all fuels, laminar burning velocities were found to decrease with increase initial pressure. From schlieren images, ethanol, iso-octane and n-heptane-air mixtures on the fuel rich region were found to become unstable at 0.1MPa. For all fuels, increasing initial pressure was found to get flame more unstable and narrow the stable flame region.

1012 非一様流中でのエタノール及びブタノール火炎の基礎燃焼特性に関する研究(燃焼(火炎))

1012 非一様流中でのエタノール及びブタノール火炎の基礎燃焼特性に関する研究(燃焼(火炎))

06/00553 Combustion characteristics of ethanol in a porous ceramic burner and ignition improved by enhancement of liquid-fuel intrusion in the pore with ultrasonic irradiation: Fuse, T. et al. Experimental Thermal and Fluid Science, 2005, 29, (4), 467–476.

06/00553 Combustion characteristics of ethanol in a porous ceramic burner and ignition improved by enhancement of liquid-fuel intrusion in the pore with ultrasonic irradiation: Fuse, T. et al. Experimental Thermal and Fluid Science, 2005, 29, (4), 467–476.