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Fuel-borne catalysts (FBC) have demonstrated efficacy as an important strategy for integrated diesel emission control. The research summarized herein provides new methodologies for the characterization of engine-out speciated emissions. These analytical tools provide new insights on the mode of action and chemical forms of metal emissions arising from use of a platinum and cerium based commercial FBC, both with and without a catalyzed diesel particulate filter. Characterization efforts addressed metal solubility (water, methanol and dichloromethane) and particle size and charge of the target species in the water and solvent extracts. Platinum and cerium species were quantified using state-of-the-art high resolution plasma mass spectrometry. Liquid-chromatography-triple quad mass spectrometry techniques were developed to quantify potential parent Pt-FBC in the PM extracts. Speciation was examined for emissions from cold and warm engine cycles collected from an engine dynamometer.

Results of engine bench tests and vehicle programs on light-duty and heavy-duty diesels have confirmed that a bimetallic platinum and cerium diesel fuel borne catalyst (FBC) can reduce engine out emissions and improve the performance of diesel oxidation catalysts and diesel particulate filters. Particulate emission reductions of up to 25% for the fuel borne catalyst alone, up to 50% with the FBC and oxidation catalyst and in excess of 95% with the FBC and a diesel particulate filter have been documented. Vehicle and engine bench tests confirm regeneration of filters at exhaust gas temperatures as low as 280°C-320°C. Field trials on commercial fleets have confirmed engine bench test fuel economy improvements on the order of 6%. Measurements have also confirmed that ultra-low additive dose rates of 4-8ppm do not lead to increases in ultra-fine particulate emissions and significantly reduce ash loading to diesel particulate filters.