Methanol as a Gasoline Extender-Fuel Economy, Emissions, and High Temperature Driveability

Methanol's potential as a gasoline extender has been evaluated, with data being obtained in the areas of fuel economy, exhaust emissions, and driveability. The results of tests with three cars, having carburetion spanning the range normally encountered in the existing car population, showed that methanol's effect on fuel economy and emissions could be directly related to its leaning effect on carburetion. The data suggest that any benefits in these two areas would only be significant for older, rich-operating cars. A 13-car driveability study indicated that the large increase in fuel volatility which occurs with the addition of methanol to gasoline could pose serious problems. A marked increase in vapor locking tendency was observed when no front-end volatility adjustments were made to the methanol blends. Stretchiness, a lack of expected response to throttle movement, was also found with the methanol blends. This operational characteristic, being related to excessively lean operation, was more pronounced with the newer cars tested. Phase separation is also a potential problem with methanol-gasoline blends. Data are presented which show the effect of including higher molecular weight alcohols along with the methanol. Phase separation still occurred in the presence of less than 1% water. Taken as a whole, the data suggest that, if it becomes available in large quantities, the use of methanol in applications other than in motor gasoline would be preferred.