Holding and sealing member and exhaust emission control device

Abstract

A holding and sealing member for use in an exhaust emission control device is disclosed that holds an exhaust gas treatment member. The holding and sealing member comprises a sheet member that is made of inorganic fibers and has a first surface and a second surface. The first and second surfaces are corrugated such that the corrugation height of the first surface is greater than the corrugation height of the second surface.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a holding and sealing member for use in an exhaust emission control device or the like, and an exhaust emission control device including the holding and sealing member. [0003] 2. Description of the Related Art [0004] Along with a significant increase of the number of vehicles from the beginning of the 20th century, the amount of exhaust emissions from internal combustion engines from vehicles has been rapidly increasing. The exhaust emissions are beginning to have serious effects on the global environment because various substances contained in the exhaust emissions, especially from diesel engines, cause pollution. [0005] Due to such circumstances, a variety of exhaust emission control devices have been developed and put into practical use. A typical exhaust emission control device includes a casing (metal shell) that is attached to an exhaust pipe connected to an exhaust gas manifol...

AI Technical Summary

Benefits of technology

[0014] It is preferable that the sheet member be a laminated sheet of inorganic fibers that has been subjected to a needling process. The fibers are interlocked in the thickness direction of the sheet by the needling process, so that the density of the sheet member is increased, thereby increasing the surface pressure. Moreover, the thickness of the sheet member can be reduced in a predetermined direction.

[0024] According to the above exhaust emission control device comprising the holding and sealing member of the present invention, the holding and sealing member can be easily attached to the exhaust gas treatment member. Moreover, the gas sealing properties and the performance for folding the exhaust gas treatment member can be improved because effects due to the difference between the circumferential lengths of the holding and sealing member on the outer surface side and the inner surface side are minimized.

Problems solved by technology

The exhaust emissions are beginning to have serious effects on the global environment because various substances contained in the exhaust emissions, especially from diesel engines, cause pollution.

However, with reference to FIG. 3A, these methods have a problem in that when the sheet member as the holding and sealing member is wound on, e.g., a cylindrical exhaust gas treatment member 20, “creases”18 are formed at the inner surface side of the holding and sealing member due to the difference between the circumferential lengths of the holding and sealing member on the inner surface side (the exhaust gas treatment member 20 side) and the outer surface side (the metal shell 12 side).

In that event, as the holding and sealing member loses the above-described functions, the exhaust gas treatment member 20 may drop off or may be damaged.

If the fiber diameter is increased, the problems with bulkiness of the sheet members and the problems with the creases formed in the wound sheet members will be more serious.

Images