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The use of methanol as a “clean fuel” appears to be a viable approach to reduce air pollution. However, concern has been expressed about potentially high formaldehyde emissions from stoichiometrically operated light-duty vehicles. This paper presents results from Task 1 of an emission test program conducted for the California Air Resources Board (CARB) and the South Coast Air Quality Management District (SCAQMD) to identify advanced catalyst technology to reduce formaldehyde emissions without compromising regulated emission control. A hybrid M90 test vehicle was used to evaluate 18 unaged catalyst systems for formaldehyde, methanol, gasoline derived hydrocarbon, organic material hydrocarbon equivalent mass, carbon monoxide, and oxides of nitrogen emissions. The vehicle was operated on a chassis dynamometer using the FTP driving cycle. Catalyst systems evaluated included electrically-heated, manifold, close-coupled, and underbody catalysts, as well as combinations of the above.

The use of methanol as a “clean fuel” appears to be a viable approach to reduce air pollution. However, concern has been expressed about potentially high formaldehyde emissions from stoichiometrically operated light-duty vehicles. This paper presents results from an emission test program conducted for the California Air Resources Board (CARB) and the South Coast Air Quality Management District (SCAQMD) to identify and evaluate advanced catalyst technology to reduce formaldehyde emissions without compromising regulated emission control. An earlier paper presented the results of evaluating eighteen different catalyst systems on a hybrid methanol-fueled test vehicle. (1)* This paper discusses the optimization of three of these catalyst systems on four current technology methanol-fueled vehicles. Emission measurements were conducted for formaldehyde, nonmethane organic gases (NMOG), methanol, carbon monoxide, and oxides of nitrogen emissions.

This paper describes experiments to determine the effect on exhaust emissions of starting on compressed natural gas (CNG) and then switching to gasoline once the catalyst reaches operating temperature. Carbon monoxide, oxides of nitrogen, and detailed exhaust hydrocarbon speciation data were obtained for dedicated CNG, then unleaded gasoline, and finally CNG start -gasoline run using the Federal Test Procedure at 24°C and at -7°C. The result was a reduction in emissions from the gasoline baseline, especially at -7°C. It was estimated that CNG start - gasoline run resulted in a 71 percent reduction in potential ozone formation per mile.

This paper describes experiments conducted to determine the regulated emissions, ozone-forming potentials, specific reactivities, and reactivity adjustment factors for eight butane and propane alternative fuel blends run on a light-duty vehicle, emission certified to be a California transitional low emission vehicle (TLEV) and converted to operate on liquefied petroleum gas (LPG). Duplicate EPA FTP emission tests were conducted with each fuel. Hydrocarbon speciation was utilized to determine reactivity-adjusted non-methane organic gases (NMOG) emissions for one test on each fuel. Results showed that all eight fuels could allow the converted vehicle to pass California ultra-low emission vehicle (ULEV) NMOG and oxides of nitrogen (NOx) standards. Six of the eight fuels could allow the vehicle to pass ULEV carbon monoxide (CO) standards. BUTANE has been an important gasoline blending component for many years.