Optimization of variable compression ratio diesel engine fueled with Zinc oxide nanoparticles and biodiesel emulsion using response surface methodology

In the current work, the optimization of engine parameters like compression ratio and ZnO nano-particles along with diesel-biodiesel emulsion have been explored to improve the performance, combustion, and emissions of diesel engines. The novelty of current work is no studies on optimization of engine input variables such as compression ratio, biodiesel volume fraction, water percentage, and nanoparticle concentration. The engine's input parameters were chosen to be compression ratio, biodiesel-blend ratio, water percentage, and ZnO nanoparticle concentration for optimization using response surface methodology. In accordance with Central Composite Rotating Design matrix, the experiments on the diesel engine were carried out, while multi-objective optimization was also carried out for the optimum engine responses. The optimum output engine responses of brake thermal efficiency, brake specific energy consumption, carbon monoxide, unburnt hydrocarbons, oxides of nitrogen, in-cylinder pressure, and heat release rate were 30.75%, 13.92 MJ/kW.hr, 0.057%, 34.68 ppm, 717.28 ppm, 57.61 bar, and 51.26 J/degrees A, respectively. At optimal running conditions, it yielded a composite desirability of 0.8594. Furthermore, optimized engine parameters received 18.84 of compression ratio, 18.98% of biodiesel blend ratio, 5.71% of water emulsion, and 90.9 ppm ZnO nanoparticles concentration. Confirmation experiments were carried out to validate optimization results by engine input parameters to optimal values and found satisfactory. After the optimization engine output responses are evaluated experimentally, the acceptable range of error (<5%) was reported.

Automated summary

In this study, the optimization of engine parameters and the use of ZnO nanoparticles and diesel-biodiesel emulsion were explored to improve the performance, combustion, and emissions of diesel engines. The input parameters of the engine were optimized using response surface methodology, and the experiments were carried out according to a Central Composite Rotating Design matrix. The optimized engine responses showed improved brake thermal efficiency, specific energy consumption, emissions levels, in-cylinder pressure, and heat release rate.