Exhaust gas purification apparatus for motor vehicles

Patent metadata

Field	Value
Publication number	US-10975744-B2
Application number	US-201916573010-A
Country	US
Kind code	B2
Filing date	Sep 17, 2019
Priority date	Sep 27, 2018
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

The present disclosure provides an exhaust gas purification apparatus for motor vehicles that has succeeded in suppressing peeling of a coat layer from an exhaust gas purification catalyst. Such exhaust gas purification apparatus for motor vehicles comprises: an exhaust gas purification catalyst comprising a substrate and a coat layer coated on the substrate comprising a microwave-absorbing material, a noble metal, and aluminum oxide (Al2O3); and a microwave-generating apparatus for heating the microwave-absorbing material located ahead of the exhaust gas purification catalyst with respect to an exhaust gas flow direction, wherein the microwave-absorbing material includes NiFe2O4, the noble metal includes at least one metal selected from the group consisting of platinum (Pt), palladium (Pd), and rhodium (Rh), and contents of zinc oxide (ZnO) and copper(II) oxide (CuO) in the coat layer are equivalent to or lower than the given levels.

First claim

What is claimed is:

1. An exhaust gas purification apparatus for motor vehicles comprising:
an exhaust gas purification catalyst comprising a substrate and a coat layer coated on the substrate comprising a microwave-absorbing material, a noble metal, and aluminum oxide (Al 2 O 3 ); and
a microwave-generating apparatus for heating the microwave-absorbing material located ahead of the exhaust gas purification catalyst with respect to an exhaust gas flow direction,
wherein
the microwave-absorbing material includes NiFe 2 O 4 ,
the noble metal includes at least one metal selected from the group consisting of platinum (Pt), palladium (Pd), and rhodium (Rh), wherein the coat layer further contains cerium oxide-zirconium oxide composite oxide (CeO 2 —ZrO 2 ) and nickel oxide (NiO); and wherein the NiO content in the coat layer is sufficient and ZnO and CuO in the coat layer are limited to below a level sufficient to reduce deterioration and peeling of the coat layer; and
contents of zinc oxide (ZnO) and copper(II) oxide (CuO) in the coat layer are 1% by weight or lower based on the total weight of the coat layer.

2. The exhaust gas purification apparatus for motor vehicles according to claim 1 , wherein the coat layer contains neither zinc oxide nor copper(II) oxide.

3. The exhaust gas purification apparatus for motor vehicles according to claim 1 , wherein an amount of the nickel oxide is 2% by weight to 50% by weight based on the total weight of NiFe 2 O 4 .

4. The exhaust gas purification apparatus for motor vehicles according to claim 1 , wherein an amount of the nickel oxide is 2% by weight to 50% by weight based on the total weight of NiFe 2 O 4 .

5. The exhaust gas purification apparatus for motor vehicles according to claim 1 , wherein an amount of the nickel oxide is 3% by weight to 30% by weight based on the total weight of NiFe 2 O 4 .

6. The exhaust gas purification apparatus for motor vehicles according to claim 1 , wherein an amount of the nickel oxide is 3% by weight to 30% by weight based on the total weight of NiFe 2 O 4 .

7. The exhaust gas purification apparatus for motor vehicles of claim 1 , wherein the contents of zinc oxide (ZnO) and copper(II) oxide (CuO) in the coat layer are below a threshold that reduces peeling of the coat layer in an atmosphere above 900° C.

Assignees

• Toyota Motor Co Ltd

Inventors

• Ishikawa Norio

Classifications

• B01J2235/15

  X-ray diffraction · CPC title

• B01J35/395

  Thickness of the active catalytic layer · CPC title

• B01J23/10

  of rare earths · CPC title

• B01D2255/20761

  Copper · CPC title

• B01D2255/2065

  Cerium · CPC title