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EPA published the first results from evaluations of electrically heated catalyst (EHC) technology for light-duty automotive applications. Since then, a number of automakers, suppliers, and government agencies have published results from their heated catalyst development and evaluation programs. EPA has evaluated a number of start catalyst systems incorporating an EHC start catalyst followed by a larger, conventional main catalyst. These systems have proven very effective at reducing cold start related emissions from methanol vehicles at low mileage. This paper compares the results from several EHC + main catalyst evaluations conducted by EPA.

The Schatz Heat Battery stores excess heat energy from the engine cooling system during vehicle operation. This excess energy may be returned to the coolant upon the ensuing cold start, shortening the engine warm-up period and decreasing cold start related emissions of unburned fuel and carbon monoxide (CO). A Heat Battery was evaluated on a test vehicle to determine its effect on unburned fuel emissions, CO emissions, and fuel economy over the cold start portion (Bag 1) of the Federal Test Procedure (FTP) at 24°C and -7°C ambient conditions. The Heat Battery was mounted in a vehicle fueled alternately with indolene clear (unleaded gasoline) and M85 high methanol blend fuels. Several Heat Battery/coolant flow configurations were evaluated to determine which would result in lowest cold start emissions.

Fresh, resistively heated quick light-off catalysts were obtained from two industry sources and evaluated on a neat methanol-fueled vehicle. Catalyst air assist was used, and a larger volume main converter was also added behind each quick light-off catalyst. The objective of this testing was to reduce excess unburned fuel, carbon monoxide, and formaldehyde emissions over the cold start portion (Bag 1) of the Federal test procedure (FTP) at 24°C. The lowest emission rates occurred with the use of a two-catalyst system (resistively heated/air assisted quick light-off catalyst and conventional main catalyst). Bag 1 conversion efficiencies in excess of 99 percent from no-catalyst levels were noted for unburned fuel and formaldehyde, and 96 percent for carbon monoxide with these two catalyst systems.

This paper details the results of testing certain M1OO neat methanol prototype vehicles and emissions control technology with methanol vehicle applications. Two M100-fueled prototype vehicles utilizing 4 valve per cylinder technology and lean operating strategies were evaluated for emissions and fuel economy profiles. Gasoline equivalent fuel economies for the methanol vehicles were calculated and compared with fuel economy profiles from comparable gasoline-fueled vehicles. Palladium: cerium and base metal catalysts on resistively heated metal monolith substrates were also evaluated for use as methanol-fueled light-duty vehicle catalysts.

A Methanol catalyst test program has been conducted in two phases. The purpose of Phase I was to determine whether a base metal or lightly-loaded noble metal catalyst could reduce Methanol engine exhaust emissions with an efficiency comparable to conventional gasoline engine catalytic converters. The goal of Phase II was the reduction of aldehyde and unburned fuel emissions to very low levels by the use of noble metal catalysts with catalyst loadings higher than those in Phase I. Catalysts tested in Phase I were evaluated as three-way converters as well as under simulated oxidation catalyst conditions. Phase II catalysts were tested as three-way converters only. For Phase I, the most consistently efficient catalysts over the range of pollutants measured were platinum/rhodium configurations. None of the catalysts tested in Phase I were able to meet a NOx level of 1 gram per mile when operated in the oxidation mode.