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The activity and durability of a platinum-rhodium automotive three-way catalyst were investigated as a function of lead and manganese fuel levels using a pulse-flame combustor. Total hydrocarbons, carbon monoxide, and nitric oxide conversions and three-way (HC/CO/NO) conversion efficiency windows were determined for approximately 24,000 combustor-simulated miles. The window for 80% HC/CO/NO efficiency disappeared at approximately 9,000 miles, 13,500 miles, and 4,500 miles for 0.5 g of lead per gallon of fuel, 0.0625 g of manganese per gallon of fuel, and a combined manganese and lead misfueling study, respectively. The catalyst's nitric oxide reduction activity displayed the greatest sensitivity to catalytic poisoning with both lead and manganese fuels.

Regulated and unregulated exhaust emissions from four late model 3-way catalyst passenger cars were measured over the urban dynamometer driving schedule of the Federal Test Procedure as a function of ambient temperature (50°F-81°F). Fuel economy, regulated emissions HC, CO, NOx, and unregulated emissions NH3, HCN, N2O, CH4, COS, H2S, SO2, SO4, and C6H6 were studied. It was found that reduced ambient temperature operation (<68°F) significantly increased the regulated emissions HC and CO, and slightly increased several unregulated emissions. Within the limitations of this study, none of the unregulated emissions were emitted at concentrations that could be considered hazardous to the public.

The gaseous and particulate emissions from a light-duty diesel powered passenger car were measured by a variety of chemical analysis techniques for three different fuels, typical No. 1 and No. 2 commercial diesel fuels and the Federal Register No. 2-D smoke test fuel. Hydrocarbon emissions were found to be inversely related to fuel molecular weight. The NO2/NO ratio was found to be much higher than for gasoline engines approaching 0.3 at low load. Particulate emissions were approximately 0.3 grams/mile for all fuels and driving cycles tested. Sulfate emissions were high, approaching that of some catalyst cars. Sulfate emissions decreased with decreasing fuel sulfur and increased by a factor of two in highway driving over urban driving. The potential pollution problems with such cars are worthy of further study.