Enhancing performance, reducing emissions, and optimizing combustion in compression ignition engines through hydrogen, nitrogen, and EGR addition: An experimental study

Abstract

Traditional hydrocarbon-based fuels are known for their emissions of partially burned hydrocarbons, nitrogen oxides, and carbon monoxide. The demand for alternative fuels to replace petroleum-based fossil fuels has been steadily increasing over the past decade due to concerns over air pollution, environmental issues, petroleum production uncertainties, and reducing dependence on petroleum products. In this study, hydrogen, EGR (Exhaust Gas Recirculation), and nitrogen were introduced into COME20 (Corn oil methyl ester) fuel. The addition of nitrogen with 26.64% hydrogen and 20% EGR resulted in a decrease in Brake Thermal Efficiency (BTE) and reduced levels of NOx emissions. Various concentrations of nitrogen (6.66%, 9.99%, and 13.32%) were investigated with 26.64% hydrogen and 20% EGR, and the performance, emission, and combustion parameters were evaluated and compared to COME20 and neat diesel. Notably, when nitrogen was absent (0%) and hydrogen and EGR were present at 26.64% and 20% respectively, an increase in BTE was observed compared to the combinations with nitrogen. The addition of nitrogen led to higher levels of CO and HC emissions compared to COME20 and neat diesel at all loads. However, the addition of any percentage of nitrogen with 26.64% hydrogen and 20% EGR resulted in reduced NOx emissions. Additionally, the study revealed a decline in heat release rate and cylinder pressure with the introduction of nitrogen and EGR alongside hydrogen, in contrast to COME20 and diesel. Finally, increasing quantities of nitrogen led to an increase in the ignition delay period.