Abstract
Coal is considered one of the major fuels alternative to petroleum. The possibility of its use in combustion engines is particularly great in marine engines, and its use could reduce fuel costs considerably.
This paper presents the engine performance and exhaust gas emissions with Coal Oil Mixtures (COM; in the experiment carbon black was used instead of coal slurry) and Solvent Refined Coal-II (SRC-II) as diesel fuel substitutes. Properties of the fuels when blended with diesel fuel and their spray characteristics are also presented.
The results of the experiment show that specific heat consumption and exhaust smoke were improved when 5w-% carbon black or 25v-% SRC-II were blended with the diesel fuel. However engine noise and NOx emissions increased with the increase in the carbon or SRC-II ratio in the fuel. The analysis of the indicator diagrams show that these fuels result in larger premixed combustion and shorter combustion duration compared with conventional diesel fuels.
Both COM and SRC-II have higher viscosity than diesel fuels; the paper shows their viscosities in empirical formula as a function of the blending ratios. In spite of the higher viscosities, the spray atomization of these alternative fuels was better than diesel fuel.
