Evaluating Lean Combustion Cycle Stability and Emissions in Spark Ignition Engines with Gasoline, Ethanol, and Methanol Blends

Fuels for vehicles account for a large portion of the world’s total energy demand, which in turn leads to increased carbon emissions. Ethanol and methanol are a fuel with a simple carbon chain and OH- bonds. It has similar properties to gasoline, and ethanol can be made from the fermentation of plant carbohydrates, called bioethanol. The advantage of using bioethanol is that it contributes to carbon neutrality. This paper will investigate the use of three manually blended gasoline ethanol and methanol (GEM) fuels in a spark ignition engine to address cycle-to-cycle variation (CCV), knock potential, and emissions with lean blend conditions. In the experiments conducted, the air-fuel ratio was conditioned lean by utilizing an electronic control unit to adjust the injector spray duration. This experiment provides results that there is a potential for mild knocking on the use of alcohol fuel with lean fuel mixture conditions at engine speed 4000 RPM, while at engine speed 6000 RPM and 8000 RPM the use of GEM tends to be stable, but in the CCV results the increase in COV (coefficient of variation) value using GEM fuel tends to be more sloping, especially with the addition of more methanol. Emission results from the use of GEM produce top emission CO2 value obtained by the E5M15 mixture at λ=1.2 and an engine speed of 8000 RPM, with a value of 13.75% and then peak CO2 emissions at a value of λ = 1.2 whereas in the use of pure gasoline peak CO2 is at a value of λ = 1.1.