Characterization of Emissions from a Variable Gasoline/Methanol Fueled Car

Abstract

In response to the occurrence of the increasingly severe ambient ozone exceedances, regional environmental managers are examining the possibility of a cleaner fuel for automobiles. At this time the leading candidate appears to be methanol. In anticipation of a shift to methanol, flexible-fueled automobiles capable of operating on gasoline and/or methanol are being developed. This study examines both the exhaust and evaporative emissions from a prototype General Motors Variable Fuel Corsica. Results are reported for tests conducted at temperatures of 40 degrees, 75 degrees, and 90 degrees F, and for fuels M0 M25, M50, M85, and M100. In addition to regulated emissions and fuel economy, emission rates for methanol, aldehydes, and a large number of hydrocarbon compounds were measured. The data indicate that increasing the fuel's methanol content does not affect the exhaust organic emission rate (calculated in accordance with the regulation) from flexible-fueled cars, but formaldehyde and methanol comprise increasingly greater portions of the organic material while hydrocarbons comprise less. Increasing fuel methanol content has no significant effect on exhaust regulated emission rates (organic material, carbon monoxide, and nitrogen oxides) nor on the composition of total hydrocarbons, except for methane, which increases substantially. The effect of ambient temperature on both exhaust and evaporative emissions is similar to its effect on gasoline cars: organic and carbon monoxide exhaust emissions increase substantially at the lower temperatures, and evaporative emissions increase steadily with increases in temperature.

Analysis of motor vehicle sources and their contribution to ambient hydrocarbon distributions at urban sites in Toronto during the Southern Ontario oxidants study

“…This exhaust profile was reported to give the best statistical performance measures when compared to other exhaust profiles in CMB modelling in recent tunnel studies (Wittorff et al, 1994). While this particular source profile did not include isoprene explicitly, measurements from several recent emissions testing programs indicate the presence of isoprene (2-methyl-l,3-butadiene) in exhaust from gasoline burning vehicles (Gabele, 1990;CARB, 1991;Coordinating Research Council, 1991). Isoprene is likely a combustion species due to its absence or negligible levels in gasoline.…”

“…The corresponding average levels of isoprene were found to be 0.158% and 0.201 % of the NMHCexhaust mass, respectively. Data from a study on emissions from a methanol flexible fueled vehicle (FFY) by Gabele (1990) indicated levels of isoprene of 0.37% of the NMHC exhaust mass when the vehicle was operating on 100% gasoline. The NMHC fraction of isoprene in the exhaust was found to decrease as the percentage of methanol in the test fuel was Table 2 was extended to include 0.18 % isoprene based upon the 28 vehicle average found in the current and older fleets of tbe AQIRP study.…”

Alcohol Fuels

“…The vehicle testing performed to date has shown that methanol FFVs can provide emissions benefits. Figure 5 shows the emissions from a GM Corsica for various gasoline methanol mixtures (40). This vehicle was designed to meet the California standards of 0.155 g/km hydrocarbon, 2.1 g/km CO, and 0.25 g/km NO x .…”

Fuel-cycle emissions for conventional and alternative fuel vehicles : an assessment of air toxics.

“…However, because M85 vehicles are also expected to have lower THC emissions than gasoline vehicles, secondary formaldehyde emissions are expected to be approximately 40% lower (EPA 1989). Gabele (1990) has also pointed out that most of the primary formaldehyde emissions occur during the cold-start portion of emissions tests. Modifications in the catalytic converters installed on these vehicles may significantly reduce formaldehyde emissions (CARB 1997b).…”