An Enabling Study of Low Temperature Combustion With Ethanol in a Diesel Engine

Abstract

Previous research indicates that the low temperature combustion (LTC) is capable of producing ultralow nitrogen oxides (NOx) and soot emissions. The LTC in diesel engines can be enabled by the use of heavy exhaust gas recirculation (EGR) at moderate engine loads. However, when operating at higher engine loads, elevated demands of both intake boost and EGR levels to ensure ultralow emissions make engine controllability a challenging task. In this work, a multifuel combustion strategy is implemented to improve the emission performance and engine controllability at higher engine loads. The port fueling of ethanol is ignited by the direct injection of diesel fuel. The ethanol impacts on the engine emissions, ignition delay, heatrelease shaping, and cylindercharge cooling have been empirically analyzed with the sweeps of different ethanoltodiesel ratios. Zerodimensional phenomenological engine cycle simulations have been conducted to supplement the empirical work. The multifuel combustion of ethanol and diesel produces lower emissions of NOx and soot while maintaining the engine efficiency. The experimental setup and study cases are described, and the potential for the application of an ethanoltodiesel multifuel system at higher loads has been proposed and discussed.