Liquid cooling device in internal combustion engines and process for manufacturing same

Abstract

The invention relates to an apparatus for liquid cooling of an internal combustion engine ( 11 ) and a process for producing it. The apparatus of the invention comprises a cooling circuit ( 13 ) which comprises at least one cooling channel ( 23, 24, 41 ) for a liquid coolant which is in thermal contact with at least one component ( 12 a, 12 b, 31 ) of the internal combustion engine ( 11 ), wherein a wall of the cooling channel ( 23, 24, 41 ) which comes into contact with the coolant has a microstructured surface having a certain porosity and roughness at least in a subregion. According to the invention, such an apparatus is produced by constructing a cooling circuit for a liquid coolant which has cooling channels which can at least partly be brought into thermal contact with the internal combustion engine, wherein a microstructured surface is produced on at least part of the walls of the cooling channels which come into contact with the liquid coolant.

1 . An apparatus for cooling an internal combustion engine ( 11 ) comprising a cooling circuit ( 13 ) which comprises at least one cooling channel ( 23 ,  24 ,  41 ) for a liquid coolant which is in thermal contact with at least one component ( 12   a,    12   b,    31 ) of the internal combustion engine ( 11 ),
 wherein a wall of the cooling channel ( 23 ,  24 ,  41 ) which comes into contact with the coolant has a microstructured surface at least in a subregion.   
   
   
       2 . The apparatus according to  claim 1  wherein the microstructured surface has a mean surface roughness Ra in the range from 1 to 1500 μm. 
   
   
       3 . The apparatus according to either  claim 1  or  2 , wherein the microstructured surface has a porous structure. 
   
   
       4 . The apparatus according to  claim 3 , wherein the mean size of the pores of the microstructured surface is in the range from 1 to 500 μm. 
   
   
       5 . The apparatus according to either  claim 3  or  4 , wherein the proportion of pores is in the range from 1 to 90%. 
   
   
       6 . The apparatus according to any of  claims 3  to  5 , wherein the microstructured surface having a porous structure has a layer thickness of from 1 to 10 000 μm. 
   
   
       7 . The apparatus according to any of  claims 3  to  6 , wherein the structures of the microstructured surface are arranged regularly. 
   
   
       8 . The apparatus according to any of  claims 3  to  6 , wherein the structures of the microstructured surface are arranged randomly. 
   
   
       9 . The apparatus according to any of  claims 1  to  8 , wherein at least the sections of the wall or walls of the cooling channel which are subjected to high thermal stress in operation have the microstructured surfaces. 
   
   
       10 . The apparatus according to any of  claims 1  to  9 , wherein the component of the internal combustion engine ( 11 ) which is in thermal contact with at least one cooling channel ( 23 ,  24 ,  41 ) is a cylinder head ( 12   a ) and/or at least a crankcase ( 12   b ) of the internal combustion engine and/or an exhaust gas cooler ( 31 ). 
   
   
       11 . The apparatus according to any of  claims 1  to  10 , wherein an aqueous coolant which comprises surface-active additives, in particular surfactants, circulates in the cooling circuit. 
   
   
       12 . A process for producing an apparatus for cooling an internal combustion engine, in which a cooling circuit for a liquid coolant which has cooling channels which are at least partly in thermal contact with the internal combustion engine is constructed, wherein a microstructured surface is produced on at least part of the walls of the cooling channels which come into contact with the liquid coolant. 
   
   
       13 . The process according to  claim 12 , wherein the microstructured surface is produced by mechanical and/or chemical treatment of the walls. 
   
   
       14 . The process according to  claim 12 , wherein the microstructured surface is produced by application or deposition of a coating material on the walls. 
   
   
       15 . The process according to  claim 12 , wherein the microstructured surface is produced during casting of the internal combustion engine.