Catalytic converter manufacturing method

Abstract

A method for manufacturing a catalytic converter having a ceramic substrate comprises sizing a housing of a catalytic converter over a substrate and intumescent mat subsequently to heating the converter, the heating causing the intumescent mat to at least reach a temperature at which the intumescent mat swells.

I claim:  
     
         1 . A method of manufacturing catalytic converters comprising: 
 sizing a housing of a catalytic converter over a substrate and intumescent mat subsequently to heating said converter, said heating causing said intumescent mat to at least reach a temperature at which said intumescent mat swells.    
     
     
         2 . The method of  claim 1 , said method further comprising: 
 wrapping said substrate with said mat, forming a wrapped substrate and    stuffing said wrapped substrate into said housing prior to said heating.    
     
     
         3 . The method of  claim 2  wherein said stuffing comprises increasing the gap bulk density to a mount density no more than about 0.7 g/cm 3 .  
     
     
         4 . The method of  claim 1  wherein said sizing comprises compressing said housing over said substrate to a GBD of about 1.0 g/cm 3 .  
     
     
         5 . The method of  claim 1  further comprising allowing said mat to relax subsequent to said sizing.  
     
     
         6 . The method of  claim 1  further comprising, adding connection ends on said housing subsequent to said sizing, said adding comprising one of forming and welding said connection ends.  
     
     
         7 . The method of  claim 1  further comprising allowing said mat to relax subsequent to said sizing, and adding connection ends on said housing subsequent to said sizing.  
     
     
         8 . The method of  claim 7  wherein said allowing and said adding occurring concurrently.  
     
     
         9 . The method of  claim 7  wherein said adding comprises plastically deforming said housing to form one of said connection ends.  
     
     
         10 . The method of  claim 7  wherein said adding comprises welding one of said connection ends onto said housing.  
     
     
         11 . The method of  claim 1  further comprising: 
 wrapping said substrate with said mat, forming a wrapped substrate;  
 stuffing said wrapped substrate into said housing prior to said heating;  
 allowing said mat to relax subsequent to said sizing; and  
 adding connection ends on said housing subsequent to said sizing by one of forming and welding said connection ends.  
 
     
     
         12 . The method of  claim 11  wherein said stuffing comprises increasing the gap bulk density to a mount density no more than about 0.7 g/cm 3 .  
     
     
         13 . The method of  claim 12  wherein said heating comprises heating said converter to at least about 500° C.  
     
     
         14 . The method of  claim 1  wherein said heating comprises heating said converter to at least about 500° C.  
     
     
         15 . The method of  claim 14  wherein said heating comprises heating said converter to a maximum temperature less than about 600° C.