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 (NOx) 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 NOx 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 NOx emissions from diesel engines.