The performance and emission of an AVL 5402 single-cylinder engine fueled with acetone-butanol-ethanol (ABE) / diesel blends were experimentally investigated at various load conditions and injection timings. The fuels tested in the experiments were ABE10 (10% ABE, 90% diesel), ABE20 and diesel as baseline.
Thermodynamics analyses of pressure traces acquired in experiments were performed to show the impact of ABE concentration to the overall combustion characteristics of the fuel mixtures. Cumulative heat release analysis showed that ABE mixtures generally retarded the overall combustion phasing, ignition delays of ABE-containing fuels were significantly extended, however, combustion rate during CA10∼CA50 were accelerated at different extent. Pressure rise rate of ABE-containing fuels further implicated that the premixed combustion were more dominant than that of diesel. Polytropic indices of both expansion and compression strokes were calculated from p-V diagram. Decreased polytropic indices of ABE-containing fuels showed incomplete combustion during power stroke, especially at late-injection conditions. Emission measurement showed that the addition of ABE mixtures will result in higher HC emissions at late injection timings, which further proved the conclusions. However, it is observed that by advancing injection timing, this disadvantage can be improved.
The results in this research implied that by proper tuning of the injection quantity and injection timing, ABE-diesel mixtures have the potential of improving combustion efficiency and reducing pollutant emission of diesel engines. With the low-cost of its industrial production, ABE can be a promising alternative transportation fuel.