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This paper describes aldehyde and unburned fuel emissions (UBF) measurements made on several light-duty, methanol-fueled vehicles with developmental 2.5-L engines and production and three-way catalytic converters. Emissions data were obtained under both steady-state and Federal Test Procedure (FTP) driving-cycle conditions. The data were then compared to those from a similarly equipped production gasoline vehicle. Before- and after-catalyst aldehyde and UBF emissions data are presented for three vehicle types as a function of equivalence ratio. In addition, aldehyde emission data for one of the methanol vehicles using a base-metal catalyst are discussed. The steady-state tests showed that both before- and after-catalyst aldehyde and UBF emissions are minimized by vehicle operation at lean equivalence ratios. The data also showed that formaldehyde accounted for 98% of the total aldehydes from the methanol vehicles, and only 31-54% of the total aldehydes from the gasoline vehicle.

An analytical method for the determination of hydrocarbon and ether emissions from gasoline-, methanol-, and flexible-fueled vehicles is described. This method was used in Phase I of the Auto/Oil Air Quality Improvement Research Program to provide emissions data for various vehicles using individual reformulated gasolines and alternate fuels. These data would then be used for air modeling studies. Emission samples for tailpipe, evaporative, and running loss were collected in Tedlar bags. Gas chromatographic analysis of the emissions samples included 140 components (hydrocarbons, ethers, alcohols and aldehydes) between C1 and C12 in a single analysis of 54-minutes duration. Standardization, quality control procedures, and inter-laboratory comparisons developed and completed as part of this program are also described.