Multi-aspect assessment and multi-objective optimization of preheated tallow biodiesel-diesel blend as alternate fuel in CI engine

Abstract

This study meticulously examined the impact of preheated tallow biodiesel on the performance and emission characteristics of a diesel engine. Employing a single-cylinder, water-cooled diesel engine configured with exhaust gas recirculation in this investigation, exhaust gas temperature (EGT) could be used to preheat the biodiesel, reducing its viscosity and density. This improvement in viscosity and density could enhance the injection process, which is often hindered by the higher density and viscosity of biodiesel compared with diesel fuel. The investigation achieved a peak preheat temperature of 70°C for the biodiesel, leading to notable improvements in brake thermal efficiency and brake power, particularly under high-load conditions. A significant reduction in emissions was observed, with hydrocarbon and carbon monoxide levels decreasing by 46.87% and 50%, respectively, when using preheated biodiesel. To refine the engine's performance further, this study utilized response surface methodology (RSM) for the optimization of operational parameters, including injection timing, engine load, and biodiesel preheat temperatures. Optimal conditions were identified at an injection timing of 21° before top dead centre, a preheat temperature of 64°C, and an engine load of 45.45% for which output response was 18.68% brake thermal efficiency, 307°C EGT, 0.0247% vol. CO, 15.32 ppm hydrocarbons, and 131.37 ppm nitrogen oxides (NOx). The successful implementation of preheated tallow biodiesel signifies a crucial step forward in the pursuit of a more sustainable and efficient transportation industry. This advancement holds the promise of reducing reliance on traditional fossil fuels, thereby contributing to the global efforts towards achieving a more environmentally friendly energy landscape.