Pillar shaped honeycomb structure, exhaust gas purifying device, exhaust system, and method for producing honeycomb structure

Patent metadata

Field	Value
Publication number	US-2021115825-A1
Application number	US-202017136420-A
Country	US
Kind code	A1
Filing date	Dec 29, 2020
Priority date	Aug 10, 2018
Publication date	Apr 22, 2021
Grant date	—

Abstract

A pillar shaped honeycomb structure includes: a porous partition wall that defines a plurality of cells, the cells forming flow paths for a fluid, the cells extending from an inflow end face to an outflow end face; and an outer peripheral wall located at the outermost circumference. At least a part of surfaces of the partition walls has a surface layer, and the surface layer includes magnetic particles and has permeability.

First claim

1 . A pillar shaped honeycomb structure, comprising:
a porous partition wall that defines a plurality of cells, the cells forming flow paths for a fluid, the cells extending from an inflow end face to an outflow end face; and an outer peripheral wall located at the outermost circumference; wherein at least a part of surfaces of the partition wall has a surface layer, and wherein the surface layer comprises magnetic particles and has permeability.

2 . The pillar shaped honeycomb structure according to claim 1 , wherein at least one surface of the partition wall is covered with the surface layer.

3 . The pillar shaped honeycomb structure according to claim 1 , wherein the magnetic particles have a curie temperature of more than 450° C.

4 . The pillar shaped honeycomb structure according to claim 1 , wherein the surface layer has a porosity of 50% or more.

5 . The pillar shaped honeycomb structure according to claim 1 , wherein the surface layer has an average pore diameter of 10 μm or less.

6 . The pillar shaped honeycomb structure according to claim 1 , wherein the magnetic particles have a weight average particle diameter of 20 μm or less.

7 . The pillar shaped honeycomb structure according to claim 1 , wherein the surface layer has a thickness of from 10 to 80 μm.

8 . The pillar shaped honeycomb structure according to claim 1 , wherein the pillar shaped honeycomb structure is formed of a ceramic material.

9 . The pillar shaped honeycomb structure according to claim 8 , wherein the ceramic material is at least one selected from the group consisting of cordierite, silicon carbide, aluminum titanate, silicon nitride, mullite, and alumina.

10 . The pillar shaped honeycomb structure according to claim 1 , wherein the magnetic particles have a shortest diameter d of from 0.1 to 5 μm, and satisfy L/d≥3, in which L (μm) is a longest diameter of the magnetic particles.

11 . The pillar shaped honeycomb structure according to claim 10 , wherein the magnetic particles are needle-shaped or scale-shaped.

12 . The pillar shaped honeycomb structure according to claim 1 , wherein the pillar shaped honeycomb structure comprises a stress relaxation layer between the surface layer and the partition wall, the stress relaxation layer having a thermal expansion coefficient between thermal expansion coefficients of the surface layer and the partition wall.

13 . The pillar shaped honeycomb structure according to claim 1 , wherein the cells comprise: a plurality of first cells which are opened on a side of inflow end face and have plugged portions at the outflow end face; and a plurality of second cells which are opened on a side of the outflow end face and have plugged portions at the inflow end face.

14 . A pillar shaped honeycomb structure, comprising:
a porous partition wall that defines a plurality of cells, the cells forming flow paths for a fluid, the cells extending from an inflow end face to an outflow end face; and an outer peripheral wall located at the outermost circumference; wherein at least a part of surfaces of the partition wall has a surface layer, and wherein the surface layer comprises needle-shaped or scale-shaped magnetic particles.

15 . An exhaust gas purifying device, comprising:
the pillar shaped honeycomb structure according to claim 1 ; a coil wiring that spirally surrounds an outer circumference of the pillar shaped honeycomb structure; and a fixing member for fixing the coil wiring to an interior of an exhaust gas flow path, the fixing member being positioned outside the coil wiring.

16 . An exhaust system, comprising:
an exhaust muffler; the exhaust gas purifying device according to claim 15 , the exhaust gas purifying device being provided in the exhaust muffler; and a silencer provided in the exhaust muffler.

17 . A method for producing a pillar shaped honeycomb structure, comprising:
a porous partition wall that defines a plurality of cells, the cells forming flow paths for a fluid, the cells extending from an inflow end face t to an outflow end face; and an outer peripheral wall located at the outermost circumference, wherein the method comprises a step of forming a surface layer in at least a part of surfaces of the partition wall, the surface layer comprising magnetic particles and having permeability.

18 . The method according to claim 17 , wherein the step of forming the surface layer comprising the magnetic particles and having permeability comprises covering at least one surface of the partition with the surface layer.

19 . The method according to claim 17 , wherein the step of forming the surface layer comprising the magnetic particles and having permeability comprises the steps of:
pouring a slurry comprising magnetic particles and a binding material based on a metal or glass into the cells to form a coated film; and heating the coated film at a temperature equal to or higher than a melting point of the metal or a softening point of the glass to form the surface layer.

20 . The method according to claim 17 , wherein the step of forming the surface layer comprising the magnetic particles and having permeability comprises the steps of:
pouring a slurry comprising magnetic particles and an adhesive material based on silica or alumina into the cells to form a coated film; and heating the coated film to solidify the silica or alumina to form the surface layer.

21 . The method according to claim 17 , wherein the step of forming the surface layer comprising the magnetic particles and having permeability comprises a step of allowing a gas comprising magnetic particles to flow into the cells.

22 . The method according to claim 17 , wherein the magnetic particles have a curie temperature of more than 450° C.

23 . The method according to claim 17 , wherein the surface layer has a porosity of 50% or more.

24 . The method according to claim 17 , wherein the surface layer has an average pore diameter of 10 μm or less.

25 . The method according to claim 17 , wherein the magnetic particles have a weight average particle diameter of 20 μm or less.

26 . The method according to claim 17 , wherein the surface layer has a thickness of from 10 to 80 μm.

27 . The method according to claim 26 ,
wherein the pillar shaped honeycomb structure is formed of a ceramic material, and wherein the ceramic material is at least one selected from the group consisting of cordierite, silicon carbide, aluminum titanate, silicon nitride, mullite, and alumina.

28 . The method according to claim 17 , wherein the magnetic particles have a shortest diameter d of from 0.1 to 5 μm, and satisfy L/d≥3, in which L (μm) is a longest diameter of the magnetic particles.

29 . The method according to claim 27 , wherein the magnetic particles are needle-shaped or scale-shaped.

Assignees

• Ngk Insulators Ltd

Inventors

• Miyairi Yukio
• Shimoda Takehide
• Aoki Takashi
• Sakamoto Hirofumi
• Masuda Masaaki
• Kondo Atsuo
• Izumi Yunie
• Kato Kyohei
• Wakita Norihiro

Classifications

• B01D46/2474

  of the walls along the length of the honeycomb · CPC title

• B01D46/2476

  Monolithic structures · CPC title

• B01D46/24494

  Thermal expansion coefficient, heat capacity or thermal conductivity · CPC title

• B01D46/24492

  Pore diameter · CPC title

• B01D46/24491

  Porosity · CPC title