Catalytic converter for exhaust gas purification

Abstract

A catalytic converter (11) for exhaust gas purification is formed by disposing a retaining mat (14) between an inner peripheral face of a metal shell (12) and an outer peripheral face of a catalyst support (13), and retaining the catalyst support (13) in an interior of the metal shell (12) by the retaining mat (14). Since a thickness of the retaining mat (14) in a released state after being heated by exhaust gas is 210% or greater of a clearance (α) between the inner peripheral face of the metal shell (12) and the outer peripheral face of the catalyst support (13), it is possible to reliably retain the catalyst support (13) over a long period of time by compensating for a decrease in surface pressure due to deterioration of the retaining mat (14) with an increase in the surface pressure due to sufficient expansion of the retaining mat (14). Moreover, since it is unnecessary to strongly compress the retaining mat (14) when assembling so as to enhance the surface pressure, there is no possibility that the catalyst support (13) will be damaged by excessive surface pressure.

1 . A catalytic converter for exhaust gas purification, in which a retaining mat disposed between an inner peripheral face of a metal shell and an outer peripheral face of a catalyst support retains the catalyst support in an interior of the metal shell,
 wherein characterized in that a thickness of the retaining mat in a released state after being heated by exhaust gas is 210% or greater of a clearance between the inner peripheral face of the metal shell and the outer peripheral face of the catalyst support.   
     
     
         2 . A catalytic converter for exhaust gas purification, in which a retaining mat disposed between an inner peripheral face of a metal shell and an outer peripheral face of a catalyst support retains the catalyst support in an interior of the metal shell,
 wherein a thickness of the retaining mat in a released state after being heated by exhaust gas is 170% or greater of a thickness of the retaining mat in a released state before being heated by exhaust gas.   
     
     
         3 . The catalytic converter for exhaust gas purification according to  claim 1 , wherein a density of the retaining mat in a released state before being heated by exhaust gas is 100 g/cm 3  or greater. 
     
     
         4 . The catalytic converter for exhaust gas purification according to  claim 2 , wherein a density of the retaining mat in a released state before being heated by exhaust gas is 100 g/cm 3  or greater.