NOx emissions reduction through applying the exhaust gas recirculation (EGR) technique for a diesel engine fueled with a diesel-biodiesel‑diethyl ether blend

Renewable energy sources support energy security and decrease dependence on dwindling fossil fuel resources. The utilization of renewable energy as a sustainable alternative aids in emissions reduction from diesel engines. A numerical study was conducted to investigate the application of exhaust gas recirculation (EGR) in a diesel engine, which was fueled with a diesel-biodiesel blend and diethyl ether (DEE) as an additive. The validation was performed using the experimental data of a diesel engine fueled by an 80% diesel and a 20% biodiesel blend (D80B20); good agreement was found between the experimental and numerical results. The aim of the current study is to reduce the concentration of the nitrogen oxide (NO_x) emissions by applying the EGR technique while utilizing an optimum value of 5% DEE in a diesel-biodiesel blend. The numerical study was conducted using the Ricardo WAVE program. The EGR proportions used were 10%, 20%, and 30%. The NO_x emissions decreased by 59% when 30% EGR was applied, with a decrease of only 5.6% in the engine thermal efficiency. In addition, when 30% EGR was applied, the heat release rate decreased by 27.6%, the combustion duration increased from 33.7° to 48.8°, and the ignition delay increased by 5.3%. These results indicate that applying EGR and DEE can significantly decrease the concentration of NO_x emissions from diesel engines.