Combined mixture process design approach for flexible fuel maps development of ternary blends operated gasoline engine

Alternate means of harnessing energy are currently being researched. However, not all demographics are in a position to switch over to these alternatives while complying with the change in existing infrastructure. The present study aspires to evaluate the effectiveness of ternary fuel blends in existing automotive engines to offer a more flexible mode of operation without demanding any modifications to the existing spark-ignition (SI) engine. It focuses on the compatibility between biofuels and pure gasoline as a flexi-fuel alternative in internal combustion engines (ICE) for improved combustion characteristics. Butanol and Lemon Peel Oil (LPO) are highly competitive renewable biofuels for use in internal combustion engines due to their many advantages. Empirical research is conducted on studying mixtures at different engine speeds and blend concentrations. Accordingly, a combined mixture process design model is developed by virtue of the Design of Experiments (DOEs). ANOVA or analysis of variance method is employed, in addition, to determine the influence of input parameters on output parameters. From the results, it is observed that utilizing pure gasoline or a blend with 90% gasoline produced the least amount of peak cylinder pressure (Pmax) alongside minimum levels of mean gas temperature (MGT), and cumulative heat release rate (CHRR). This indicated a lower efficiency of fuel combustion when using higher proportions of gasoline in the blend. Additionally, engine speed is found to have a significant influence over all the performance parameters where it exhibited an inverse relationship which showed that higher engine speed produced inferior results and vice versa. The desirability matrix yields the most optimal blend, displaying a substantial desirability score of 0.683 running on 50% gasoline, 20% n-butanol, and 30% LPO, at 1523.485 rpm. A comparison between the results of Pmax, CHRR, and MGT between pure gasoline and the optimal blend yields a performance enhancement of 16%, 0.5%, and 6.4%, respectively. Overall, from the research, both butanol and LPO meet the ascribed expectations and are observed to significantly enhance the different combustion parameters. These results can thus be further extrapolated to ascertain the partial replacement of straight gasoline in real-life scenarios with butanol and LPO.