Catalytic converter

Patent metadata

Field	Value
Publication number	US-9597660-B2
Application number	US-201414912967-A
Country	US
Kind code	B2
Filing date	Aug 12, 2014
Priority date	Aug 22, 2013
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

A catalytic converter ( 10 ) includes a base material and a catalyst layer ( 3 ). The catalyst layer has a lower catalyst layer ( 4 ) and an upper catalyst layer ( 5 ). The upper catalyst layer is constituted by a first upper catalyst layer ( 6 ) and a second upper catalyst layer ( 7 ). The first upper catalyst layer is formed of a first carrier, which is formed of a ceria-containing oxide, and rhodium supported on the first carrier. The second upper catalyst layer is formed of a second carrier and rhodium supported on the second carrier. The second carrier does not contain ceria and is formed of one oxide selected from among zirconia and alumina. A length of the first upper catalyst layer is X % (30 to 70%) of an overall length of the base material. A length of the second upper catalyst layer is 100−X % of the overall length of the base material.

First claim

The invention claimed is:

1. A catalytic converter comprising:
a base material having a cellular structure through which exhaust gases flow; and
a catalyst layer formed on a surface of a cell wall in the base material, wherein
the catalyst layer has a lower catalyst layer and an upper catalyst layer,
the lower catalyst layer is formed on a surface of the base material along an entire length of the base material,
the upper catalyst layer is constituted by a first upper catalyst layer and a second upper catalyst layer,
the first upper catalyst layer is formed on an upstream side of a surface of the lower catalyst layer in a direction of exhaust gas flow,
an upstream side end of the base material is a starting point of the first upper catalyst layer,
the second upper catalyst layer is formed on a downstream side of the surface of the lower catalyst layer in the direction of the exhaust gas flow,
a downstream side end of the base material is a starting point of the second upper catalyst layer,
the lower catalyst layer is formed of a carrier and palladium supported on the carrier,
the first upper catalyst layer is formed of a first carrier and rhodium supported on the first carrier, the first carrier is formed of a complex oxide comprising Al 2 O 3 , CeO 2 , ZrO 2 , La 2 O 3 , Y 2 O 3 , and Nd 2 O 3 ,
the second upper catalyst layer is formed of a second carrier and rhodium supported on the second carrier, the second carrier being formed of a complex oxide comprising Al 2 O 3 , ZrO 2 , La 2 O 3 , and Nd 2 O 3 ,
a length of the first upper catalyst layer in the direction of the exhaust gas flow is 30 to 70% of an overall length of the base material, and
a length of the second upper catalyst layer in the direction of the exhaust gas flow is a length obtained by subtracting the length of the first upper catalyst layer from the overall length of the base material,
wherein the first carrier is formed of a ceria-containing zirconia complex oxide, and the second carrier is formed of a zirconia complex oxide that does not contain ceria.

Assignees

• Toyota Motor Co Ltd

Inventors

• Aoki Yuki

Classifications

• B01J35/57

  Honeycombs · CPC title

• B01J37/0244 Primary

  Coatings comprising several layers · CPC title

• B01J23/10 Primary

  of rare earths · CPC title

• B01J37/0018

  Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat) · CPC title

• B01J23/002

  Mixed oxides other than spinels, e.g. perovskite · CPC title