Development of Passive HC/NOx Trap Catalysts for Low Temperature Gasoline Applications

The goal of the proposed project is to develop combined HC/NOx adsorber catalysts for use on both stoichiometric and lean engines. The development of more efficient internal combustion engines represents a key enabler for decreasing CO2 emissions and reducing the consumption of petroleum. However, the lower exhaust temperatures which result from improvements to engine efficiency represent a challenge to the control of pollutant emissions. Standard aftertreatment technologies such as three-way catalysts (TWCs) fail to function efficiently at low temperatures, from which it follows that high efficiency internal combustion engines require new and/or improved technologies which specifically address this issue. This is made imperative by the implementation of Tier 3 legislation, which will require that both NOx and hydrocarbons (HC) are effectively controlled during cold starts. Moreover, the implementation of new combustion technologies such as HCCI, RCCI, etc., will also require aftertreatment systems which can function effectively at the low exhaust temperatures which typify their normal operation. As outlined below, HC/NOx adsorbers represent a promising technology for the abatement of emissions at low temperatures, i.e., in the region when conventional catalysts are inoperative. However, HC/NOx adsorbers possess deficiencies in terms of their durability and ability to function under stoichiometric conditions. We propose to address these deficiencies, with the goals of (i) developing a viable technology for use in gasoline and diesel applications, i.e., viable with respect to both HC/NOx trapping efficiency and catalyst durability; and (ii) developing a system model which will allow the prediction of performance under a range of operating conditions.