Exploration of combustion processes and spray characterizations of Acetone-Butanol-Ethanol (ABE) in a constant volume chamber

Butanol, in comparison with ethanol, has more similar properties of current transportation fuel. These means it has a potential of being a more suitable blend for use in diesel engines. Unfortunately, butanol has a high cost of production. Acetone-butanol-ethanol (ABE) is an intermediate product of the fermentation process of butanol production. By using ABE directly in diesel fuels instead of butanol, the separation and purification processes are eliminated. As a result, it has a potential for greatly decreasing the overall cost for fuel production. This could lead to a larger commercial use of ABE-diesel blends on the market. Research has been conducted over the past five years regarding spray and combustion processes of both neat ABE and ABE-diesel blends. The main focus of this paper is to review the efforts made in fundamental spray research under quasi-steady flow field environments provided by a high-temperature, high-pressure constant volume chamber. Heat release rates high-speed Mie-scattering images were acquired from in-cylinder pressure traces to characterize liquid spray penetration. Natural flame luminosity was also captured to depict spatial and temporal soot distribution. It is observed that the acetone content has a major influence in the combustion behavior of the ABE mixture. As the acetone content increases, the combustion phasing significantly advances. Butanol is able to compensate the advancing effect caused by acetone and ethanol. Additionally, butanol can increase the overall energy density of the mixture and as a result makes the properties of the mixture closer to that of diesel.