Corrosion resistant bi-metal charge air cooler

Abstract

A heat exchanger assembly for an automotive vehicle includes at least one tube having an internal layer and an external layer. The external layer is an aluminum based material, and the internal layer is a stainless steel based material. At least one turbulator is disposed inside the tube and is formed of a stainless steel based material.

1 . A heat exchanger assembly for an automotive vehicle comprising:
 at least one tube having an internal layer and an external layer, said external layer comprising an aluminum based material, and said internal layer comprising a stainless steel based material.   
   
   
       2 . The heat exchanger of  claim 1  further comprising:
 at least one turbulator disposed inside said tube, said turbulator comprising a stainless steel based material.   
   
   
       3 . The heat exchanger of  claim 2  wherein said at least one tube is made of a stainless steel clad aluminum strip coil. 
   
   
       4 . The heat exchanger of  claim 2  wherein said stainless steel based material comprises a steel in the austenitic or ferritic grades. 
   
   
       5 . The heat exchanger of  claim 2  wherein said tube and said turbulator are brazed together at each peak and trough of said turbulator to said interior surface of said tube. 
   
   
       6 . The heat exchanger of  claim 2  wherein said tube is roll-formed into a lock seam. 
   
   
       7 . The heat exchanger of  claim 2  further comprising a header formed of aluminum clad with brazing alloy. 
   
   
       8 . The heat exchanger of  claim 2  further comprising a header formed of aluminum clad with a stainless steel based material. 
   
   
       9 . The heat exchanger of  claim 2  further comprising at least one end cap formed of aluminum. 
   
   
       10 . The heat exchanger of  claim 2  further comprising at least one end cap formed of stainless steel. 
   
   
       11 . The heat exchanger of  claim 2  further comprising at least one end cap formed of aluminum clad with stainless steel. 
   
   
       12 . A method of making a heat exchanger, comprising:
 providing a sheet of stainless steel clad aluminum having a first and a second end;   providing a turbulator of stainless steel based material;   forming said stainless steel clad aluminum sheet into a tube so that an interior surface of said tube is stainless steel;   locating said turbulator inside said tube; and   placing said tube in a core assembly.   
   
   
       13 . The method of  claim 12  wherein said sheet is formed into said tube to form a fluid passageway by roll-forming said first and second ends of said sheet. 
   
   
       14 . The method of  claim 12  wherein said sheet comprises two C-channels brazed together to form said tube. 
   
   
       15 . The method of  claim 12  wherein said turbulator is brazed to said interior surface of said tube. 
   
   
       16 . A tube for a heat exchanger, comprising:
 a generally cylindrical housing having an internal layer comprising a stainless steel based material and an external layer comprising an aluminum based material.   
   
   
       17 . The tube for a heat exchanger of  claim 16 , further comprising:
 at least one turbulator disposed inside said housing, said turbulator comprising a stainless steel based material.