Hexagonal-cell honeycomb structure

Abstract

A hexagonal-cell honeycomb structure having a plurality of cell walls having a hexagonal shape in cross-section and forming a plurality of hexagonal cell passages, and a tubular skin layer surrounding the cell walls, The thickness of the basic cell walls is 140 μm or less and an inscribed circle diameter Da inscribed at an intersectional portion of the basic cell walls 2 and an cell pitch P having the relationship Da/P≧0.13.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view that shows a hexagonal-cell honeycomb structure according to a first example embodiment of the present invention;

FIG. 2 is a partial front view that shows the hexagonal-cell honeycomb structure of FIG. 1;

FIG. 3 illustrates an example defining of Da according to the present invention;

FIG. 4 illustrates an example defining of Da according to the present invention;

FIG. 5 illustrates an example defining of Da according to the present invention;

FIG. 6 illustrates an example defining of Da according to the present invention;

FIG. 7 illustrates a hexagonal-cell honeycomb structure according to a second example embodiment of the present invention; and

FIG. 8 illustrates an exhaust gas purification apparatus of an internal combustion engine according to a third example embodiment of the present invention.

Claims

1. A hexagonal-cell honeycomb structure comprising: a plurality of cell walls having a hexagonal shape in cross-section and forming a plurality of hexagonal cell passages;a tubular skin layer surrounding said a plurality of cell walls; and whereina thickness of basic cell walls forming said hexagonal shape in cross-section is 140 μm or less and a diameter Da of an inscribed circle at an intersectional portion of said basic cell walls, and a cell pitch P have the relationship Da/P≧0.13.

2. A hexagonal-cell honeycomb structure according to claim 1, wherein said relationship is Da/P≧0.16,

3. A hexagonal-cell honeycomb structure according to claim 1, wherein a diameter Db of a circle Ca contacting opening outlines of three walls, at intersectional portions of outermost cell walls forming a cross-sectional irregular hexagonal-cell shape with said tubular skin layer or at intersectional portions of outermost cell walls and said basic cell walls, and said diameter Da have the relationship Db/Da≧1.05.

4. A hexagonal-cell honeycomb structure according to claim 1, wherein said basic wall thickness is 110 μm or less.

5. A hexagonal-cell honeycomb structure according to claim 1, wherein a porosity of said cell wall is 40% or less.

6. A hexagonal-cell honeycomb structure according to claim 1, said cell wall is made of cordierite material.

7. A hexagonal-cell honeycomb structure comprising: a plurality of cell walls having a substantially hexagonal shape in cross-section and forming a plurality of hexagonal cell passages;a tubular skin layer surrounding said a plurality of cell walls; and whereina thickness of basic cell walls forming said hexagonal shape by with six cell walls, and without said tubular skin layer is 140 μm or less and an average value Dax of diameter Da of a circle contacting the open outline of said three hexagonal cell passages at an intersectional portion formed by said three basic cell walls and cell pitch P having a relationship Dax/P≧0.13.

8. A hexagonal-cell honeycomb structure according to claim 7, wherein said relationship of said formula of Dax/P≧0.16.

9. A hexagonal-cell honeycomb structure according to claim 7, wherein said basic wall thickness is 110 μm or less.

10. A hexagonal-cell honeycomb structure according to claim 7, wherein a average diameter Dbx of a circle Ca contacting opening outlines of three walls, at intersectional portions of outermost cell walls forming cross-sectional irregular hexagonal-cell shape with said tubular skin layer or at intersectional portions of outermost cell walls and said basic cell walls, and said diameter Da have the relationship Dbx/Dax≧1.05.

11. A hexagonal-cell honeycomb structure according to claim 7, wherein said hexagonal-cell honeycomb structure is made of cordierite material.

12. A hexagonal-cell honeycomb structure comprising: a plurality of cell walls having a hexagonal shape in cross-section and forming a plurality of hexagonal cell passages;a tubular skin layer surrounding said a plurality of cell walls;a first area having a shape similar to an outer circumferential shape of said tubular skin layer and including a center of said honeycomb structure;a second area defined between said skin layer and said first area; and whereina thickness of basic cell walls forming said hexagonal shape in cross-section with six cell walls and without said tubular skin layer is 140 μm or less, said first area S1 and said second area S2 have the relationship S2/S1=0.2, and 80% in all intersections forming said second area comply with the relationship Dax/P≧0.13, where Dax is defined as a diameter of a circle contacting opening outlines of three cell passages at an intersectional portion formed by said three basic cell walls and p is defined a cell pitch.

13. A hexagonal-cell honeycomb structure according to claim 12, wherein said basic wall thickness is 110 μm or less.

14. A hexagonal-cell honeycomb structure according to claim 12, wherein a porosity of said cell walls is 40% or less.

15. A hexagonal-cell honeycomb structure according to claim 12, wherein said cell walls are made of cordierite material.

16. An exhaust gas purifying system comprising: a first exhaust gas purifying portion;a second exhaust gas purifying portion disposed downstream of said first exhaust gas purifying portion;a hexagonal-cell honeycomb structure disposed in said first exhaust gas purifying portion; and whereina thickness of basic cell walls forming a hexagonal shape in cross-section of said hexagonal-cell honeycomb structure is 140 μm or less and a diameter Da of an inscribed circle at an intersectional portion of said basic cell walls, and a cell pitch P have the relationship Da/P≧0.13.

17. An exhaust gas purifying system comprising: a first exhaust gas purifying portion;a second exhaust gas purifying portion disposed downstream of said first exhaust gas purifying portion;a hexagonal-cell honeycomb structure comprising a plurality of cell walls having a substantially hexagonal shape in cross-section and forming a plurality of hexagonal cell passages and a tubular skin layer surrounding said a plurality of cell walls; and whereinsaid hexagonal-cell honeycomb structure disposed in said first exhaust gas purifying portion and a thickness of basic cell walls forming said hexagonal shape with six cell walls and without said tubular skin layer is 140 μm or less and an average value Dax of diameter Da of a circle contacting the open outline of said three hexagonal cell passages at an intersectional portion formed by said three basic cell walls and cell pitch P having a relationship Dax/P≧0.13.

18. An exhaust gas purifying system comprising: a first exhaust gas purifying portion;a second exhaust gas purifying portion disposed downstream of said first exhaust gas purifying portion;a hexagonal-cell honeycomb structure comprising a plurality of cell walls having a substantially hexagonal shape in cross-section and forming a plurality of hexagonal cell passages and a tubular skin layer surrounding said a plurality of cell walls; and whereinsaid hexagonal-cell honeycomb structure disposed in said first exhaust gas purifying portion and a thickness of basic cell walls forming said hexagonal shape in cross-section with six cell walls and without said tubular skin layer is 140 μm or less, said first area S1 and said second area S2 have the relationship S2/S1=0.2, and 80% in all intersections forming said second area comply with the relationship Dax/P≧0.13, where Dax is defined as a diameter of a circle contacting opening outlines of three cell passages at an intersectional portion formed by said three basic cell walls and p is defined a cell pitch.