Use of Butanol Blend Fuels on Diesel Engines - Effects on Combustion and Emissions

Butanol, a four-carbon alcohol, is considered in the last years as an interesting alternative fuel, both for Diesel and for Gasoline application. Its advantages for engine operation are: good miscibility with gasoline and diesel fuels, higher calorific value than Ethanol, lower hygroscopicity, lower corrosivity and possibility of replacing aviation fuels. Like Ethanol, Butanol can be produced as a biomass-based renewable fuel or from fossil sources.
In the research project, DiBut (Diesel and Butanol) addition of Butanol to Diesel fuel was investigated from the points of view of engine combustion and of influences on exhaust aftertreatment systems and emissions. One investigated engine (E1) was with emission class “EU Stage 3A” for construction machines, another one, engine (E2) was HD Euro VI. The operation of engine (E1) with Bu30 was instable at lower part load due to the lower Cetane Number of the blend fuel. The electronic control system of the engine (E2) compensated very well the varying properties of fuels.
With higher Butanol content, there is a lower heat value of the fuel and there is lower torque at full load.
The PM-emissions with Bu30 are lower, so the soot loading of DPF takes a longer time.
For all investigated engines, the Butanol rate (Bu30) can be considered as a limit for a problem-free engine starting and operation.