Assessment of environmentally friendly fuel emissions from in-use vehicle exhaust: low-blend iso-stoichiometric GEM mixture as example

Abstract

Gasoline-ethanol-methanol fuel blends were formulated with the same stoichiometric air-to-fuel ratio and volumetric energy concentration as any binary ethanol-gasoline blend. When the stoichiometric blends operated in a vehicle, the time period, injector voltage, and pressure for each fuel injection event in the engine corresponded to a given stoichiometric air-to-fuel ratio, and the load was essentially constant. Three low oxygen content iso-stoichiometric ternary gasoline-ethanol-methanol fuel blends were prepared, and the properties were compared with regular-type fuel without added oxygen. One of the ternary fuels was tested using a fleet of in-use vehicles for15 weeks and compared to neat gasoline without oxygenated compounds as a reference. Only a small number of publications have compared these ternary fuels in the same engine, and little data exist on the performance and emissions of in-use spark-ignition engines. The total hydrocarbon emissions observed was similar in both fuels, in addition to the calculated ozone forming potential of the tailpipe and evaporative emissions. In ozone non-attainment areas, the original purpose for oxygenate gasolines was to decrease carbon monoxide emissions. The results suggest that the strategy is less effective than expected because there still exist a great number of vehicles that have suffered the progressive deterioration of emissions and do not react to oxygenation, while new vehicles are equipped with sophisticated air/fuel control systems, and oxygenation does not improve combustion because the systems adjust the stoichiometric point, making it insensitive to the origin of the added excess oxygen (fuel or excess air). Graphical abstract Low level ternary blend of gasoline-ethanol-methanol were prepared with the same stoichiometric air-fuel ratio and volumetric energy concentration, based on the volumetric energy density of the pre-blended components. Exhaust and evaporative emissions was compared with a blend having no oxygen in a fleet of 12 in-use vehicles. Vehicles that had suffer a normal deterioration of emissions and do not react to oxygenation, and new vehicles with more sophisticated air/fuel control systems do not improve combustion.

Modelo termodinámico de un motor de ignición por chispa que funciona con mezclas de gasolina con aditivos oxigenantes

“…Para dichos experimentos se ha utilizado un motor monocilíndrico equipado con sensores para medir las variables más significativas durante su desempeño y sus emisiones contaminantes. Entre los trabajos realizados por González y Schifter, 2017 [1], y Schifter et al, 2017 [2][3][4][5][6] se ha trabajado con mezclas de gasolina con aditivos oxigenantes con contenidos de hasta un 20% en masa de oxígeno, con mezclas de gasolina-etanol-metanol con bajo contenido de oxígeno, con mezclas de gasolina con alcoholes, éteres y DMC con un 3.5 % en masa de oxígeno, con mezclas de MTBE con gasolina regular, con mezclas de gasolina con EtOH, ETBE y DMC a niveles de 2.8 % en masa de oxígeno, entre otras. En algunos resultados se observó que el uso de oxigenantes reduce los contenidos de hidrógeno y carbono, y que el contenido de oxígeno está asociado directamente con las emisiones de CO y CO2, e inversamente asociado con emisiones NOx mientras que los combustibles con contenido de hidrógeno están directamente asociados con las emisiones de NOx e inversamente con las de CO2.…”

Kinetic Modeling Study of Laminar Burning Velocity of Gasoline–Ethanol–Methanol Blends at Elevated Temperature and Pressure

“…A 3500-km road test with 13 different GEM-fueled vehicles was performed by Schifter et al [11]. This study reported that the use of oxygenated fuels was not effective in reducing emission in old vehicles, whereas similar fuel consumption and emission as pure gasoline were obtained.…”

The effects of addition of co-solvents on the physicochemical properties of gasoline–methanol blended fuels

“…Many previous studies have focused on the impact of burning primary methanol, ethanol, or isopropyl alcohol (IPA)−gasoline blends on the emission performance of spark ignition (SI) engines. 10–12…”