Combustion Analysis of Jatropha Methyl Ester and Its Ethanol and Acetone Blends in a Diesel Engine

The present study analyzes the heat release and combustion characteristics of diesel, pure biodiesel (B100) obtained from Jatropha oil and its 80% blending with Ethanol (BD80E20) and Acetone (BD80AC20) as fuels in a single cylinder four stroke direct injection (DI) diesel engine. The analyses of experimental results indicate that the pressure of the in-cylinder gases rise early in case of B100, BD80E20 and BD80AC20. Early rate of pressure rise causes the cylinder pressure to rise early in case of the alternate fuels with a resulting low peak rate of pressure rise and peak pressure. The Net Heat Release Rate (NHRR) analysis shows lower rate of heat release with B100, BD80AC20 during the premixed phase of combustion. However, the rate of heat release is higher for these fuels in the diffusion combustion phase. As a result, the cumulative heat release (CHR) is higher for B100 and BD80AC20 as compared to that of normal diesel. The pressure in the fuel line was remarkably higher for B100, while the biodiesel ethanol blend shows almost the same trend and the fuel pressure is slightly lower for BD80AC20 when compared with diesel fuel pressure. Ignition delay in case of B100, BD80E20 and BD80AC20 is less compared to normal diesel; however, there was slight increase in delay period with addition of ethanol and acetone in B100. Combustion durations are longer for all these alternate fuels as compared to that of conventional diesel.