Evaluation and optimization of hydrogen addition on the performance and emission for biodiesel dual-fuel engines with different blend ratios based on the response surface method

Problems such as air pollution caused by engine burning fossil fuels are becoming increasingly severe. Consequently, the pursuit of clean and efficient energy alternatives, as well as enhancements in the combustion of fossil fuels, have emerged as potential avenues for resolving these challenges. Firstly, a 3D simulation model of the engine is made using the CONVERGE program. Then, the biodiesel-hydrogen (0%, 5%, 10%, and 15%) blends are employed to investigate the combustion processes for the diesel-fuel engine at various loading (50%, 75%, and 100%). Finally, the response surface approach is employed to optimize the biodiesel-hydrogen engines' combustion and emission parameters. The findings demonstrate that combustion pressure and temperature in engine cylinders will also rise as the hydrogen level increases. The hydrogen addition to the engine can enhance its combustion and emission properties. The outcomes prove that 0.656 is the ideal value for multi-objective optimization analysis using the response surface method. The engine reaches optimal working conditions when the hydrogen energy percentage is 6.9%, the load is 100%, and EGR is 7.7%. At this moment, the BSFC, BTE, HC, and NOx emissions were 208.31 g/(kW·h), 41.06%, 340 ppm, and 490 ppm, respectively.