Exhaust gas purification device for vehicle has oxygen storage catalyst connected in series to ammonia production catalyst and ammonia storage and nitrogen oxide reduction catalyst

摘要

An exhaust gas purification device has an oxygen storage catalyst (2) connected in series to an ammonia production catalyst (1) and an ammonia storage and nitrogen oxide reduction catalyst (3). The oxygen storage catalyst intermediately stores oxygen in the operating phases with a lean exhaust gas composition and oxidizes pollutants in the operating phases with a rich exhaust gas composition. An Independent claim is also included for a process for operating an exhaust gas purification device comprising switching between operating phases with a lean exhaust gas composition and phases with a rich exhaust gas composition. Preferred Features: The ammonia production catalyst and the oxygen storage catalyst are both made of a precious metal catalyst material, the oxygen storage catalyst containing a larger amount of CeO2. The ammonia production catalyst and the nitrogen oxide reduction catalyst is made of a catalyst material with a mixture of TiO2, WO3 and V2O5.