Exhaust Treatment Device Insulation System

1 . A method of assembling an exhaust treatment device, comprising:

positioning fibrous insulation within a flexible container;

evacuating air from the flexible container;

compressing the insulation to reduce its volume 30 to 80 percent;

sealing the flexible container to maintain the compressed shape of the insulation; and

positioning the flexible container and compressed insulation between an inner shell and an outer shell of an exhaust treatment device.

2 . The method of claim 1 further including obtaining first and second outer shell halves, positioning the flexible container and the insulation between the inner shell and one of the first and second outer shell halves, and fixing the first and second outer shell halves to one another.

3 . The method of claim 2 further including positioning another reduced volume of insulation sealed within another flexible container between the inner shell and the other of the first and second outer shell halves.

4 . The method of claim 3 further including clamping one of the inner and outer shells to a tubular housing containing one of a diesel particulate filter, a diesel oxidation catalyst and a selective catalytic reduction device.

5 . The method of claim 1 wherein the inner shell defines a cavity adapted to receive an exhaust flow from an engine.

6 . The method of claim 1 further including melting the flexible container by passing heated gas across an inner surface of the inner shell.

7 . The method of claim 6 further including allowing the previously compressed insulation to expand in the absence of a vacuum to fill a cavity between the inner and outer shells.

8 . The method of claim 1 further including puncturing the flexible container.

9 . The method of claim 8 further including allowing the previously compressed insulation to expand in the absence of a vacuum to fill a cavity between the inner and outer shells.

10 . The method of claim 1 further including extending a tube through the inner and outer shells and fixing the tube to one of the inner and outer shells.

11 . The method of claim 1 wherein the inner and outer shells include steel sheets.

12 . The method of claim 1 wherein the flexible container includes a plastic bag.

13 . An exhaust treatment device, comprising:

an inner shell;

an outer shell;

a flexible container; and

fibrous insulation positioned within the flexible container, the insulation being compressed 30 to 80 percent by volume, the flexible container being sealed to maintain a compressed state of the insulation, wherein the flexible container and the compressed insulation are positioned between the inner shell and the outer shell.

14 . The exhaust treatment device of claim 13 wherein the outer shell includes a first outer shell half fixed to a second outer shell half.

15 . The exhaust treatment device of claim 14 further including a tube extending through the inner and outer shells in fluid communication with a cavity defined by the inner shell.

16 . The exhaust treatment device of claim 15 wherein the cavity is adapted to receive an exhaust flow therethrough.

17 . The exhaust treatment device of claim 16 further including an exhaust treatment device substrate positioned within a housing, the inner and outer shells being fixed to the housing, wherein the cavity is in fluid communication with the substrate.

18 . The exhaust treatment device of claim 13 wherein the insulation and flexible container are shaped to a predetermined contour prior to being positioned between the inner and outer shells.

19 . The exhaust treatment device of claim 18 wherein the flexible container is sealed to maintain the predetermined contour.

20 . The exhaust treatment device of claim 14 further including another flexible container having compressed insulation therein, the another flexible container being positioned adjacent the flexible container, the another flexible container engaging the first outer shell half and the flexible container engaging the second outer shell half.