Emission of carbon dioxide from mobile sources is receiving interest as part of a coordinated approach to limit greenhouse gases. Coupled with the relatively high price of gasoline in some countries this has resulted in the development of lean burn and direct injection gasoline engines. These engines will require conversion of nitrogen oxides (NOx) in excess of 70% in a net oxygen rich exhaust stream to meet future emission limits.
This paper describes recent advances in the performance of NOx trap technology in terms of adsorption capacity, temperature of operation and thermal durability. The application of a new NOx trap together with a newly developed starter catalyst, to a direct injection gasoline vehicle shows that European stage IV limits can be reached for NOx and CO with a fresh system.