Defeat of the Soot/NOx Trade off Using Biodiesel Ethanol in a Moderate Exhaust Gas Recirculation Premixed Low Temperature Combustion Mode

Abstract

The soot/nitric oxides (NOx) tradeoff of diesel, biodiesel, and biodiesel–ethanol in a moderate exhaust gas recirculation (EGR) premixed low temperature combustion (LTC) mode is investigated in this study. Compared to diesel, biodiesel demonstrates poorer spray behavior and shorter ignition delay, but its oxygen content results in less soot. Blending ethanol into biodiesel enhances spray behavior, prolongs ignition delay, and further increases fuel oxygen fraction, resulting in a larger reduction in soot. In the moderate EGR premixed low temperature combustion mode, an obvious soot/NOx tradeoff is demonstrated with diesel fuel. The soot/NOx tradeoff is improved by biodiesel fuel and defeated by the biodiesel–ethanol blend. Low soot, low NOx, and high combustion efficiency are achieved with the biodiesel–ethanol blend and proper EGR rate.