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Aldehyde and unburned fuel emissions (UBF) were measured from experimental 6V-92TA and 6V-71N methanol-fueled heavy-duty diesel engines. The 6V-71N engine was tested with experimental oxidation catalytic converters. Formaldehyde accounted for 97-99% of the total aldehydes emitted from both engines. Aldehyde and unburned fuel concentrations were highest in the idle modes of the 13-mode test and decreased with increasing engine speed and load. The 13-mode weighted aldehyde and UBF emissions for the 6V-92TA engine were 0.10 G/BHP-HR and 2.01 G/BHP-HR, respectively. The 13-mode aldehyde and UBF emissions from the 6V-71N engine before catalytic treatment were 0.32 G/BHP-HR and 4.51 G/BHP-HR, respectively. These emissions were reduced to 0.19 G/BHP-HR and 1.10 G/BHP-HR with catalytic treatment. Total aldehyde emissions from the methanol-fueled engines compared favorably with the 0.07 to 0.28 G/BHP-HR range reported for heavy-duty conventionally fueld diesel engines.

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.