MOUNTING MAT AND EXHAUST GAS TREATMENT DEVICE
A mounting mat for an exhaust gas treatment device includes a mounting mat of inorganic fibers having a first major surface and a second major surface opposite the first major surface, wherein the first major surface has an elongation different from that of the second major surface. An exhaust gas treatment device including the mounting mat and methods for making the mounting mat and the exhaust gas treatment device are also provided.
1 . A mounting mat for an exhaust gas treatment device comprising a sheet of inorganic fibers having a first major surface and a second major surface opposite said first major surface, wherein the first portion of said mat has an elongation different from that of a second portion of said mat.
2 . The mounting mat of claim 1 , wherein the first major surface has an elongation different from that of the second major surface.
3 . The mounting mat of claim 1 , wherein the sheet of inorganic fibers comprises at least one layer of inorganic fibers.
4 . The mounting mat of claim 3 , wherein at least two layers of inorganic fibers are heat pressed together to form the sheet of inorganic fibers.
5 . The mounting mat of claim 4 , wherein the at least two layers of inorganic fibers have the same or different fiber compositions.
6 . The mounting mat of claim 3 , wherein the first major surface of the mounting mat is capable of stretching to a length greater than the second major surface of the mounting mat upon application of the same tensile load to the first and second major surfaces without cracking the mounting mat.
7 . The mounting mat of claim 6 , wherein said first major surface comprises an inner surface of the mounting mat and wherein the second major surface comprises an outer surface of the mounting mat.
8 . The mounting mat of claim 7 , wherein the outer surface of the mounting mat is capable of stretching to a length greater than the inner surface of the mounting mat upon application of the same tensile load to the outer and inner surfaces without cracking the mounting mat.
9 . The mounting mat of claim 8 , wherein the amount and/or type of binder utilized on the outer surface of the mounting mat varies from the type of binder utilized on the inner surface of the mounting mat.
10 . The mounting mat of claim 9 , wherein the amount of binder, type of binder and/or length of fibers utilized on the outer surface of the mounting mat varies from the amount of binder, type of binder and/or length of fibers utilized on the inner surface of the mounting mat.
11 . An exhaust gas treatment device comprising:
a housing;
a fragile structure resiliently mounted within the housing; and
a mounting mat disposed in a gap between the housing and the fragile structure, wherein the mounting mat comprises a sheet of inorganic fibers having a first major surface and a second major surface opposite said first major surface, wherein a first portion of said mat has an elongation different from that of a second portion of said mat.
12 . The exhaust gas treatment device of claim 11 , wherein the first major surface has an elongation different from that of the second major surface.
13 . The exhaust gas treatment device of claim 11 , wherein the sheet of inorganic fibers comprises at least one layer of inorganic fibers.
14 . The exhaust gas treatment device of claim 11 , wherein at least two layers of inorganic fibers are heat pressed together to form the sheet of inorganic fibers.
15 . The exhaust gas treatment device of claim 14 , wherein the at least two layers of inorganic fibers have the same or different fiber compositions.
16 . The exhaust gas treatment device of claim 12 , wherein the first major surface of the mounting mat is capable of stretching to a length greater than the second major surface of the mounting mat upon application of the same tensile load to the first and second major surfaces without cracking the mounting mat.
17 . The exhaust gas treatment device of claim 16 , wherein said first major surface comprises an inner surface of the mounting mat and wherein said second major surface comprises an outer surface of the mounting mat.
18 . The exhaust gas treatment device of claim 17 , wherein the outer surface of the mounting mat is capable of stretching to a length greater than the inner surface of the mounting mat upon application of the same tensile load to the outer and inner surface without cracking the mounting mat.
19 . The mounting mat of claim 18 , wherein the amount and/or type of binder utilized on the outer surface of the mounting mat varies from the type of binder utilized on the inner surface of the mounting mat.
20 . The mounting mat of claim 18 , wherein amount of binder, the type of binder, and/or the length of fibers utilized on the outer surface of the mounting mat varies from the length of fibers utilized on the inner surface of the mounting mat.