Optimization of fuel injection pressure for enhanced performance and emission characteristics of a diesel engine fueled with waste frying oil biodiesel blend

Abstract As concerns regarding environmental pollution and the depletion of fossil fuel resources continue to increase, the development of cleaner‐burning and sustainable alternatives for compression ignition (CI) engines has become increasingly important. Waste frying oil (WFO) biodiesel is a promising renewable energy source; however, to optimize combustion and emission performance while minimizing emission trade‐offs, operating parameters such as fuel injection pressure must be carefully optimized. This study experimentally evaluates a 20% by volume WFO biodiesel blend (B20) in a CI engine and employs response surface methodology to optimize engine performance under varying engine loads and injection pressures. The results indicate that operating the B20 blend at an optimal injection pressure (IP) of 260 bar increases cylinder pressure and heat release rate by 5%, improves brake thermal efficiency by 10%, and reduces brake‐specific fuel consumption by 5%. Furthermore, a desirability score of 0.998 confirms the high reliability of the optimized operating conditions. The optimized settings also result in a 10% reduction in carbon monoxide, hydrocarbon, and smoke emissions, although a slight increase in nitric oxide emissions is observed. Overall, the findings suggest that WFO biodiesel is a sustainable alternative fuel with significant potential to enhance engine performance and emission characteristics when used at an optimized IP, thereby contributing to environmental sustainability and pollution reduction.