Catalytic converter substrate

1. A catalytic converter substrate comprising a plurality of micro-structured tubes, each tube having an inside surface and an outside surface, wherein:

at least one of the inside surface and the outside surface has a plurality of openings to micro-channels; and

the micro-channels extend from said openings in the at least one surface towards the other surface.

2. The catalytic converter substrate of claim 1 , wherein the tubes are ceramic tubes.

3. The catalytic converter substrate of claim 1 , wherein the micro-channels extend from openings in the inside surface towards the outside surface.

4. The catalytic converter substrate of claim 1 wherein each tube comprises two distinct layers, the first layer containing the micro-channels extending from the inside surface and terminating within the tube cross-section and a second solid layer at the outside surface.

5. The catalytic converter substrate of any one of claim 4 wherein the second solid layer has a thickness of up to 70% of the thickness of the wall of the micro-structured tubes.

6. The catalytic converter substrate of claim 1 , wherein the substrate comprises one or more of: cordierite; zirconia; yttrium stabilised zirconia; titania; silicon carbide; clay; alumina; stainless steel, FeCr alloys; alloys of iron; alloys of aluminium; or sintered metals.

7. The catalytic converter substrate of claim 1 , wherein the GSA is in the range 8,000 m 2 /m 3 to 15,000 m 2 /m 3 .

8. The catalytic converter substrate of claim 1 wherein the internal diameter of the micro-structured hollow tubes is from 0.5 to 4 mm.

9. The catalytic converter substrate of claim 1 wherein the wall thickness of the micro-structured hollow tubes is in the range 100 to 500 μm.

10. The catalytic converter substrate of claim 1 wherein the micro-channels have an entrance diameter of 5 μm to 200 μm.

11. The catalytic convertor substrate of claim 1 comprising a catalytically active coating.

12. The catalytic convertor substrate of claim 1 wherein the geometric surface area of the substrate is at least 19,000 m 2 /m 3 .

13. The catalytic convertor substrate of claim 12 , wherein the geometric surface area of the substrate is in the range from 19,000 m 2 /m 3 to 35,000 m 2 /m 3 .

14. The catalytic convertor substrate of claim 1 , wherein:

the outer diameter of the micro-structured tubes is in the range from 2 mm to 4 mm; and

the wall thickness of the micro-structured tubes is in the range from 0.1 mm to 0.8 mm.

15. The catalytic convertor substrate of claim 1 , wherein:

the outer diameter of the micro-structured tubes is in the range from 2.5 mm to 4 mm; and

the wall thickness of the micro-structured tubes is in the range from 0.1 mm to 0.2 mm.

16. The catalytic convertor substrate of claim 1 , wherein the outer diameter of the micro-structured tubes is in the range from 2 mm to 4 mm; and the wall thickness of the micro-structured tubes is in the range from 0.2 mm to 1 mm.

17. The catalytic convertor substrate of claim 1 , wherein the outer diameter of the micro-structured tubes is in the range from 2.5 mm to 4 mm; and the wall thickness of the micro-structured tubes is in the range from 0.4 mm to 0.8 mm.

18. A catalytic converter comprising a catalytic convertor substrate as set out in claim 1 and having a catalytically active coating, an insulation mat and a substrate housing.

19. The catalytic converter of claim 18 wherein the catalytically active coating is a washcoat.

20. The catalytic converter of claim 18 wherein the coating comprises a precious metal.

21. The catalytic converter of claim 20 wherein the precious metal is a platinum group metal.

22. The catalytic converter of claim 18 , wherein the coating comprises a non-precious metal.

23. A kit for a catalytic converter, comprising;

a catalytic convertor substrate as a set out in claim 1 ,

an insulation mat; and

a substrate housing formed to receive the substrate and mat with a tight fit.

24. An internal combustion engine exhaust system including a catalytic converter as set out in claim 18 .