Experimental Investigation on Physico-chemical Properties of Bio-ethanol/Gasoline Blends and the Qualitative Effect of Different Blends on Gasoline Quality and Engine Performance

Physico-chemical and operational properties of various gasoline bio-ethanol blends were evaluated.
Bio-ethanol was obtained through distillation from maize (Zea mays), sugar cane (Saccharum L),
raffia (Raffia vinefera) wine, and palm wine and then purified using a rotavapor. Engine trails involved
combinations of various ratios of gasoline/bio-ethanol as fuel in a small unmodified gasoline engine
connected to a dynamometer. The vapour pressure, octane number, flash point, specific gravity, and
energy density of various compositions of the blends were evaluated. Sugar cane gave the highest
yield of alcohol 97.99 g per kg of produce while the lowest amount of alcohol of 10.5 ml per kg of
produce was obtained from palm wine. Engine power decreased from 0.400 kW with 100% gasoline
as fuel to 0.108 kW with a gasoline ethanol ratio of 1: 10. The octane number increased from 93 at
E10 to 106 at E90. The energy density decreased from 33.180 MJ/l at E10 to 23.600 MJ/l at E90.
Other physical observations suggest that to successfully run a gasoline engine with bio
ethanol/gasoline blends some modifications would have to be done on the engine, including
advancing of ignition timing, provision of air tight fuel conduit network, and modification of piston
heads to improve pre-combustion fuel homogenisation.