Catalyst system for exhaust gas purification utilizing base metals, and controlling method therefor
AssigneeToyota Jidosha Kabushiki Kaisha
InventorTakeshi Nobukawa
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Abstract
A catalyst system for exhaust gas purification which comprises a first-stage base metal catalyst located upstream and a second-stage base metal catalyst located downstream, wherein the first-stage base metal catalyst comprises at least one oxide support selected from the group consisting of alumina, ceria, zirconia, yttria, and titania and Cu metal and/or a Cu oxide supported thereon, and in cases where the amount of NOx in the exhaust gas has become or exceeded an NOx criterion, the state of the exhaust gas is switched from slightly rich to rich.
Claims12
A catalyst system for exhaust gas purification comprising a first-stage base metal catalyst located at the upstream end and a second-stage base metal catalyst located at the downstream end, wherein
- the first-stage base metal catalyst has Cu metal and/or Cu oxide supported on one or more oxide supports selected from the group consisting of alumina, ceria, zirconia, yttria and titania, and
- when the volume of NOx in the exhaust gas has become equal to or exceeded the NOx criteria, the state of the exhaust gas is switched from slightly enriched to enriched.
Dependencies are inferred from the claim text.