Abstract
The most significant obstacle to introduce engines with low fuel consumption and low emissions is the incapability to reduce NOx in lean exhaust gases. NOx-storing catalysts show, however, a possible path for the future. A detailed study of NOx conversion over NOx-storing catalysts was made. The catalysts were subjected to synthetic exhaust gases. The effect of the lambda during the rich pulse and other parameters such as oxygen, water and carbon dioxide concentrations was investigated. Competitive adsorption of SO2 was also studied. The system behaviour very much depended on the fuel sulphur level. The proposed standards increase the applicability of NOx-storing systems, but stricter regulations are necessary.