Heat exchanger and associated method

Abstract

A heat exchanger for cooling a machine fluid of a vehicle, and associated method. The heat exchanger can include a fluid inlet tank, a fluid outlet tank, and a plurality of heat transfer tubes connecting the inlet tank to the outlet tank. Each tube can include first and second substantially flat sidewalls, a plurality of internal webs extending between the first and second sidewalls, and a plurality of first dimples formed on the first sidewall, each first dimple formed over one of the webs.

1 . A heat exchanger for cooling a machine fluid of a vehicle, the heat exchanger comprising: 
 a fluid inlet tank;    a fluid outlet tank; and    a plurality of heat transfer tubes connecting the inlet tank to the outlet tank, wherein each tube comprises: 
 first and second substantially flat sidewalls;  
 a plurality of internal webs extending between the first and second sidewalls; and  
 a plurality of first dimples formed on the first sidewall, each first dimple formed over one of the webs.  
   
   
   
       2 . The heat exchanger of  claim 1 , wherein the first dimples are formed over alternate webs of the tube.  
   
   
       3 . The heat exchanger of  claim 2 , further comprising a plurality of second dimples formed on the second sidewall of each tube, each second dimple formed over one of the webs.  
   
   
       4 . The heat exchanger of  claim 3 , wherein the second dimples are offset laterally by one web relative to the first dimples.  
   
   
       5 . The heat exchanger of  claim 1 , wherein each first dimple is formed substantially centrally relative to the corresponding web.  
   
   
       6 . The heat exchanger of  claim 4 , wherein each of first and second dimples are formed substantially centrally relative to the corresponding webs.  
   
   
       7 . The heat exchanger of  claim 1 , wherein each first dimple defines a pair of fluid flow passages between the first dimple and the second sidewall.  
   
   
       8 . The heat exchanger of  claim 3 , wherein each second dimple defines a pair of fluid flow passages between the second dimple and the first sidewall.  
   
   
       9 . The heat exchanger of  claim 6 , wherein the dimples have shapes selected from the group consisting of oval, square, rectangular, polygonal, circular and rounded.  
   
   
       10 . The heat exchanger of  claim 1 , adapted for immersion in a cooling liquid.  
   
   
       11 . The heat exchanger of  claim 1 , adapted for air-cooling.  
   
   
       12 . The heat exchanger of  claim 1 , wherein the tubes are connected to the inlet and outlet tanks by brazing.  
   
   
       13 . The heat exchanger of  claim 1 , wherein the tubes are extruded from aluminum.  
   
   
       14 . The heat exchanger of  claim 1 , further comprising cooling fins positioned between the tubes.  
   
   
       15 . The heat exchanger of  claim 1 , wherein the machine fluid comprises transmission fluid.  
   
   
       16 . A method for making a heat exchanger for cooling a machine fluid, the method comprising: 
 forming a plurality of tubes having first and second substantially flat sidewalls;    coupling a first end of each tube to a fluid inlet tank;    coupling a second end of each tube to a fluid outlet tank;    forming webs between the first and second sidewalls of each tube; and    forming a plurality of first dimples on the first sidewall of each tube, each first dimple formed over one of the webs.    
   
   
       17 . The method of  claim 16 , further comprising forming the first dimples over alternate webs.  
   
   
       18 . The method of  claim 17 , further comprising forming a plurality of second dimples on the second sidewall of each tube over alternate webs of the tube.  
   
   
       19 . The method of  claim 18 , wherein forming the second dimples comprises offsetting the second dimples laterally by one web relative to the first dimples.  
   
   
       20 . The heat exchanger of  claim 1 , wherein the first and second dimples are formed substantially centrally relative to the corresponding webs.