Evaluation of ethanol as additive for NOx and PM reduction in CI engines fueled with diesel–biodiesel blends using a pump assembly

Abstract

This work describes the performance variation and emission profile of a single-cylinder diesel engine connected to a hydraulic pump controlling the engine speed and load. This hydraulic system makes it possible to measure the engine power output with simplicity and low cost. By using energy analysis, the engine performance was evaluated using four different fuels: mineral diesel; biodiesel; a diesel-biodiesel blend composed of mineral diesel (90%) and biodiesel (10%) in volume; and a ternary mixture composed of mineral diesel (82%), biodiesel (10%) and ethanol (8%) in volume. The biodiesel used in the tests came from waste cooking oil, and it was produced in the local pilot plant. Ethanol was used to decrease combustion temperature due to its high enthalpy of vaporization while increasing oxygen content in the mixture. Results revealed a slight increase in the emission of NO x emissions and a reduction in CO emissions with the increase in biodiesel content. The use of ethanol resulted in lower NO x (up to 6.5%) and PM emissions (up to 31.0%) but CO and HC emissions were increased. The energy efficiency and specific fuel consumption were increased when compared to mineral diesel when biodiesel content was increased. The introduction of ethanol caused an increase in fuel consumption as well as a slight reduction in energy efficiency.