NO.sub.X conversion of exhaust gases from lean mixture engines such as Diesel engines is improved by providing a catalytic converter having three zones, the first zone containing an NO.sub.X storage material on a .gamma.-aluminum oxide layer, the second zone having a layer with a noble metal, and the...http://www.google.com/patents/US5992142?utm_source=gb-gplus-sharePatent US5992142 - No exhaust emission control method and arrangement
