Among primary alcohols, bio-n-butanol is considered as a promising alternative fuel candidate. However, relatively low production efficiency and high cost of component recovery from the acetone-n-butanol-ethanol (ABE) or isopropanol-n-butanol-ethanol (IBE) fermentation processes hinders industrial-scale production of bio-n-butanol. Hence it is of interest to study the intermediate fermentation product, i.e. ABE and IBE as a potential alternative fuels. However, for fuel applications, the IBE mixture appears to be more attractive than ABE due to more favorable properties of isopropanol over acetone, such as being less corrosive to engine part, higher energy density and octane number. In this study, an experimental investigation on the performance, combustion and emission characteristics of a port fuel-injection SI engine fueled with IBE-gasoline blends was carried out. By comparisons between IBE-gasoline blends with various IBE content (0 vol.%-60 vol.% referred to as G100-IBE60) and more commonly used alternative alcohol fuels (ethanol, n-butanol and ABE)-gasoline blends, it was found that IBE30 performed well with respect to engine performance and emissions, including brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), carbon monoxide (CO), unburned hydrocarbons (UHC) and nitrogen oxides (NO x). Then, IBE30 was selected to be compared with G100 under various equivalence ratio (Φ=0.83~1) and engine load (300 and 500 kpa BMEP). Overall, higher BTE (0.04-4.3%) and lower CO (4%), UHC (15.1-20.3%) and NO x (3.3-18.6%) emissions were produced by IBE30 compared to G100. Therefore, IBE could be a good alternative fuel to gasoline due to the environmentally benign fermentation process (from non-edible biomass feedstock and without recovery process) and the potential to improve energy efficiency and reduce pollutant emissions.

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Alcohols, especially n-butanol, have received a lot of attention as potential fuels and have shown to be a possible alternative to pure gasoline. The main issue preventing butanol's use in modern engines is its relatively high cost of production. ABE, the intermediate product in the ABE fermentation process for producing bio-butanol, is being studied as an alternative fuel because it not only preserves the advantages of oxygenated fuels, but also lowers the cost of fuel recovery for individual component during fermentation. With the development of advanced ABE fermentation technology, the volumetric percentage of acetone, butanol and ethanol in the biosolvents can be precisely controlled. In this respect, it is desirable to estimate the performance of different ABE blends to determine the best blend and optimize the production process accordingly. In this paper, pure ABE fuels with different component volumetric ratio, (A: B: E of 3:6:1, 6:3:1 and 5:14:1), were combusted in a naturally aspirated, port-fuel injected spark ignited engine. The performance of these blends was evaluated through measurements of in-cylinder pressure, and various exhaust emissions. In addition, pure gasoline and neat n-butanol were also tested as baselines for comparison of ABE fuels. The tests were conducted at an engine speed of

Intermediate product of biobutanol production, acetone-butanol-ethanol (ABE) as an alternative fuel has drawn increasing attention in recent years due to its potential to eliminate various production costs. In this work, neat acetone-butanolethanol (ABE) with a component volumetric ratio of 3:6:1, n-butanol, and neat diesel were studied in a preburn type constant volume chamber with optical access. The ambient temperature and oxygen ranged from 800 to 1200 K and 21% to 11%, respectively, covering both conventional and low temperature combustion (LTC) regimes. Time resolved images of the spray and natural flame luminosity (indicator of soot) were captured by a high speed camera coupled with a copper vapor laser beam. The images show that the flame lift-off length and liquid penetration of n-butanol and ABE are much longer and shorter, respectively, than that of diesel under all tested conditions. This results in a longer "gap" between the liquid spray and the flame in ABE and n-butanol combustion that provides more space and time for the droplets to evaporate and mix with the ambient air, which is expected to decrease the local equivalence ratio at the combustion region. Indeed, the natural flame luminosity of ABE and n-butanol is reduced significantly under all tested conditions compared to that of diesel. For all the tested fuels, especially ABE, the combustion duration decreases with the reduction of ambient temperature due to a stronger premixed combustion, while it increases with the reduction of oxygen concentration due to the dilution effect. Therefore, ABE has a high potential to reduce soot emissions when used in diesel engines, but it would also suffer from combustion phasing retardation like butanol under LTC conditions with high EGR.

Bio-butanol has proved to be a promising alternative fuel in recent years; it is typically produced from ABE (acetone-butanol-ethanol) fermentation from non-edible biomass feedstock. The high costs for dehydration and recovery from dilute fermentation broth have so far prohibited bio-butanol's use in internal combustion engines. There is an interesting in studying the intermediate fermentation product, i.e. water-containing ABE as a potential fuel. However, most previous studies covered the use of water-containing ABE-diesel blends. In addition, previous studies on SI engines fueled with ABE did not consider the effect of water. Therefore, the evaluation of water-containing ABE gasoline blends in a port fuel-injected spark-ignition (SI) engine was carried out in this study. Effect of adding ABE and water into gasoline on combustion, performance and emissions characteristics was investigated by testing gasoline, ABE30, ABE85,

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