Assessment of the Effects of Nanofuels on Combustion and Emissions in a Diesel Engine by Considering Various Types of Nanoparticles in Combination with Biodiesel or Ethanol

Abstract

Improving the quality of fuel represents an effective solution to address the long-standing issue of engine emissions. This study adopts CeO2 and carbon nanotubes as additives, which are blended with neat diesel using a physicochemical method to produce nanofuel. The research investigated the combustion and emission performance of a high-pressure common rail four-cylinder engine under various operating conditions, utilizing different types of nanomaterials, nanoparticle sizes, and biofuel substitutes as variables. The outcomes of the study indicate superior performance of the nanofuel compared with neat diesel across all evaluated aspects. Notably, the size of the added particles directly influenced the beneficial enhancements achieved in diesel fuel. Additionally, the nanofuel containing carbon nanotubes demonstrated a greater improvement effect than the one incorporating CeO2. Furthermore, when compared with neat diesel, the combustion of carbon nanotubes (CNT) nanofuel at 100% load resulted in a notable 4.0% increase in brake thermal efficiency, coupled with reductions of 3.0% in brake specific fuel consumption and 8.8%, 4.4%, 4.9%, and 9.6% reductions, respectively, for carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and smoke emissions. It is noteworthy that the incorporation of biofuel alternatives, such as biodiesel and ethanol, into nanofuels exhibited even further enhanced effects in terms of promoting combustion and reducing emissions. The findings of this study serve as an important reference for selecting suitable nanofuels tailored to meet diverse operational demands of engines.