| CHARACTERISTICS ON NOX ADSORPTION AND INTERMEDIATES OF LNT CATALYST |
| S. C. KO1, K. C. OH2, C. K. SEO33, C. B. LEE2 |
1Jeonbuk Institute of Automotive Technology
2Korea Automotive Technology Institute
3Department of Automotive & Mechanical Engineering |
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| ABSTRACT |
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Several NOx reduction technologies under development in recent years have now been commercialized, including selective catalytic reduction (SCR) with NH3 or hydrocarbons, and Lean NOx Trap. The aim of the present study is to investigate characteristics on NOx adsorption according to the oxygen concentration, de-NOx performance according to lean/rich injection cycle and toxic intermediates at LNT downstram for lean-burn gasoline engine. Under oxygen of 6%, NOx storage capacity was the highest, showed the highest NOx conversion of 98%. The reason for this phenomena is because the excited oxygen atoms at high oxygen concentration increased oxidizing power of NO. Under low temperature of 205oC, LNT catalyst showed the least NOx conversion of 14% because its activity became lower, while the generation rate of toxic HNCO was highest as CO which is generated during the rich condition, reacts with NOx stored on Ba site. |
| Key Words:
Gasoline engine, GDI, NOx, LNT (Lean NOx Trap), NH3, HNCO (Isocyanic acid) |
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