Performance and emissions of spark-ignition engine using ethanol-methanol-gasoline, n-butanol-iso-butanol-gasoline and iso-butanol-ethanol-gasoline blends: A comparative study

The aim of this study, which is the first of its kind, is to compare experimentally the effects of different ternary blended fuels, e.g., ethanol-methanol-gasoline (EM), n-butanol-iso-butanol-gasoline (niB) and iso-butanol-ethanol-gasoline (iBE), on engine performance, combustion and pollutant emission characteristics to demonstrate the best potential one from these ternary fuel blends as alternative to fossil fuel. The experiments were performed at similar operating conditions and low content rates of fuel blends (3-10 vol% in gasoline) with varying engine speeds between 2600 and 3400 r/min at half throttle opening position of spark ignition engine. The results showed that the engine performance (volumetric efficiency, torque and brake power) increased, while pollutant emissions (carbon monoxide (CO) and unburnt hydrocarbons (UHC)) decreased at using EM fuel blends, compared to other blended fuels. It was also found that the highest emissions and the lowest performance among the blended fuels are introduced by niB, while iBE presented a moderate level of performance and emissions between niB and EM. On the other hand, the performance of niB and iBE is lower than the base fuel (neat gasoline) but EM showed a higher performance than the base fuel. The emissions of EM, niB and iBE are all lower than the base fuel.