An experimental investigation was conducted on the effect of equivalence ratios and engine loads on performance and emission characteristics using acetone?butanol?ethanol (ABE) and gasoline blends. Gasoline blends with various ABE content (0 vol % to 80 vol % ABE, referred to as G100, ABE10, ABE20, ABE30, ABE60, and ABE80, respectively) were used as test fuels, where the volumetric concentration of A/B/E was 3:6:1. The experiments were conducted at engine loads of 3, 4, 5, and 6 bar brake mean effective pressure at an engine speed of 1200 rpm and under various equivalence ratios (? = 0.83?1.25). The results showed that ABE addition in the fuel blends could increase brake thermal efficiency and decrease unburned hydrocarbon (UHC), carbon dioxide (CO), and oxynitride (NO<
sub>
x<
/sub>
). As for unregulated emissions, acetaldehyde and 1,3-budatiene emissions increased with the increased ABE content in blend fuels. Regarding the aromatic emissions, ABE addition led to a decrease in benzene, toluene, and xylene emissions. The study indicated that ABE could be used as a promising alternative fuel in spark ignition (SI) engines for enhancing the brake thermal efficiency and reducing regulated emissions and aromatic air toxics.