Optimizing Spark-Ignition Engine Performance with Ternary Blend Fuels and Hybrid Nanolubricants: A Response Surface Methodology Study

The current research elucidates the application of response surface methodology to optimize the collective impact of methanol–isobutanol–gasoline blends and nanolubricants on the operational parameters of a spark-ignition engine. Diverse alcohol blends in conjunction with gasoline are employed in engine trials at 2500 rpm across varying engine loads. The alcohol blends exhibit notable enhancements in brake thermal efficiency, peak in-cylinder pressure, and heat release rate. At 2500 rpm and 75% load, the break thermal efficiency of iBM15 surpasses that of gasoline by 33.5%. Alcohol blends significantly reduce hydrocarbon and carbon monoxide emissions compared to gasoline. The iBM15 demonstrates a reduction of 25.2% and 51.12% in vibration along the Z and Y axes, respectively, relative to gasoline. As per the response surface methodology analysis, the optimal parameters are identified: an alcohol content of 29.99%, an engine load of 99.06%, and a nanolubricant concentration of 0.1%. It is noteworthy that ternary blends can be viably employed in spark-ignition engines, offering a partial replacement for conventional fossil fuels. This research highlights that employing isobutanol–methanol–gasoline ternary blends and the ZnO-TiO₂/5W30 hybrid nanolubricant improves spark-ignition engine performance, cuts emissions, and minimizes engine vibration compared to conventional gasoline.