Combined Effects of a Biobutanol/Ethanol–Gasoline (E10) Blend and Exhaust Gas Recirculation on Performance and Pollutant Emissions

[Image: see text] Butanol is attracting more attention as an alternative fuel. The performance and emissions of butanol/ethanol–gasoline (E10) was investigated in a spark ignition engine. Exhaust gas recirculation (EGR) was employed to improve the engine performance and emissions in this reported test. The experimental results showed that high brake thermal efficiency (BTE) was observed with a high proportion of blended fuels in comparison to E10. During EGR operation, the introduction of butanol changed the combustion behavior, including prolonged ignition delay, shortened rapid burning duration, a reduced knock number, and knock intensity. The brake-specific fuel consumption (BSFC) increased with butanol addition, and when EGR was introduced, it decreased similarly to E10. The butanol–E10 blends exhibited lower exhaust gas temperature in comparison to E10 at various EGR rates. Hydrocarbon emissions from the blends increased slightly with the increased EGR rate, whereas CO emissions decreased. EGR exhibited high inhibition of NO(x) emissions for both blended fuels and E10, which were reduced by more than 80%. The NO(x) emissions from the blended fuels were 20–30% less than that of E10 with or without EGR conditions. Finally, EGR contributed to a reduction in BSFC and improvement in BTE for the butanol–E10 engine. The butanol–E10 blends exhibited a similar power performance, slightly reduced combustion stability, and acceptable emissions with respect to the baseline conditions.