Heat exchange device

Abstract

The present invention relates to a heat exchange device suitable for cooling recirculated exhaust gases in an EGR (Exhaust Gas Recirculation) system. The invention is characterized by a configuration that allows incorporating the heat exchanger in very small spaces and with the recirculated exhaust gas inlets and outlets not necessarily being aligned. It is also characterized by an inner configuration based on the stack of flat tubes configured by means of die-cut and stamped sheets configuring a complex path of the fluid to be cooled. According to embodiments, the invention is incorporated in a cavity of the engine block of an internal combustion engine with fluid communication with the liquid coolant. The present invention has an impact on protecting the environment.

1 . A heat exchanger for an EGR system adapted for heat exchange between a first fluid, the exhaust gas of an internal combustion engine, and a second fluid, a liquid coolant, comprising:
 a heat exchange tube bundle ( 1 ) formed by a stack of flat tubes ( 2 ) of rectangular section arranged parallel to one another, extending between an inlet ( 3 ) of the first fluid and an outlet ( 4 ) of the first fluid, where the flat tubes ( 2 ) of the tube bundle ( 1 ) comprise an expansion at their ends ( 2 . 1 ) in the direction of the stack of the tube bundle ( 1 ) to establish a passage space between tubes for the second fluid;   an inlet manifold ( 5 ) in fluid communication with the inlet ( 3 ) of the heat exchange tube bundle ( 1 ),   an outlet manifold ( 6 ) in fluid communication with the outlet ( 4 ) of the heat exchange tube bundle ( 1 ),   
       and wherein
 at least one of the tubes ( 2 ) of the tube bundle ( 1 ) is configured by the attachment of two flat sheets ( 2 . 2 ) with bent sides ( 2 . 3 ,  2 . 4 ) such that an inner face ( 2 . 3 . 1 ,  2 . 4 . 1 ) of the bent side ( 2 . 3 ,  2 . 4 ) of one sheet ( 2 . 2 ) is attached to the outer face ( 2 . 3 . 2 ,  2 . 4 . 2 ) of the bent side ( 2 . 3 ,  2 . 4 ) of the other sheet ( 2 . 2 ); and, 
 the directrix D-D′ of the tubes ( 2 ) of the tube bundle ( 1 ) defines a curved path. 
 
     
     
         2 . The exchanger according to  claim 1 , wherein the path of the directrix D-D′:
 either comprises a mainly longitudinal segment X-X′, 
 or else it is an S-shaped path. 
 
     
     
         3 . The exchanger according to  claim 2 , wherein one or both ends ( 2 . 1 ) of the tubes ( 2 ) show the sides ( 2 . 3 ,  2 . 4 ) as curved-shaped arcs, one having a greater radius than the other, the path of the directrix D-D′ comprising a mainly longitudinal segment X-X′, and additionally comprising a curved segment at the inlet and at the outlet of the end ( 2 . 1 ) of the tube. 
     
     
         4 . The exchanger according to  claim 3 , wherein the two ends ( 2 . 1 ) of said tubes ( 2 ) show the sides ( 2 . 3 ,  2 . 4 ) in a curve, the curve contained in the main plane of the flat tube ( 2 ), establishing a transition between the mainly longitudinal segment X-X′ and the curved segment at the inlet and at the outlet of the path of the directrix D-D′ at 90°, such that the entry direction and the exit direction of the first fluid are parallel. 
     
     
         5 . The exchanger according to  claim 1 , wherein it further comprises:
 a deflecting surface ( 9 ),   the deflecting surface ( 9 ) comprises a first portion (P 1 ) limiting or preventing the passage of the second fluid to the space located in-between the tubes ( 2 ) of the bundle of tubes ( 1 ), and   the first portion (P 1 ) is located in correspondence to the inlet of the second fluid.   
     
     
         6 . The exchanger according to  claim 5 , wherein the deflecting surface ( 9 ) comprises a second portion (P 2 ) being prolonged as a fin ( 9 . 2 ) intended to abut the wall of the cavity or to abut the housing of the heat exchanger limiting or preventing the passage of the second fluid throughout the passage located between the bundle of tubes ( 1 ) and the wall of the cavity or the wall of the housing where the bundle of tubes ( 1 ) is housed and wherein said second portion (P 2 ) is located between the inlet and the outlet of the second fluid. 
     
     
         7 . The exchanger according to  claim 5 , wherein the inlet of the second fluid is located in the proximities of the outer sides ( 2 . 4 ) configured as curved-shaped arcs at the end of the tubes ( 2 ) of the bundle of tubes ( 1 ). 
     
     
         8 . The exchanger according to  claim 5 , wherein the first portion (P 1 ) of the deflecting surface ( 9 ) is:
 either a plate ( 9 ) next to the bundle of tubes ( 1 ), or   at least one prolongation ( 2 . 4 . 4 ) of the outer side ( 2 . 4 ) of the tubes ( 2 ) of the bundle of tubes ( 1 ) being the at least one prolongation ( 2 . 4 . 4 ) prolonged towards the adjacent tube ( 2 ).   
     
     
         9 . The exchanger according to  claim 8 , wherein the first portion (P 1 ) of the deflecting surface ( 9 ) is a plate configured as a curve-shaped arc, abutted to the sides ( 2 . 4 ) as a curve-shaped arc of the ends ( 2 . 1 ) of the tubes ( 2 ) of the tube bundle ( 1 ) and wherein the deflecting surface ( 9 ) is spaced from the ends of the tube bundle ( 1 ) allowing the passage of the second fluid to a portion of the sides ( 2 . 4 ) of the tubes ( 2 ) of the tube bundle ( 1 ). 
     
     
         10 . The exchanger according to  claim 8 , wherein the deflecting surface ( 9 ) is at least one prolongation ( 2 . 4 . 4 ) of the outer side ( 2 . 4 ) of the tubes ( 2 ) prolonged towards the adjacent tube ( 2 ) and configured as a curve-shaped arc in correspondence to the curve-shaped arc of one of the ends of the tubes ( 2 ) of the bundle of tubes ( 1 ). 
     
     
         11 . The exchanger according to  claim 7 , wherein the deflecting surface ( 9 ) comprises a window ( 9 . 3 ) located in the area adjacent to the end ( 2 . 1 ) of the tubes ( 2 ) of the tube bundle ( 1 ) corresponding to the inlet ( 3 ) of the first fluid, allowing the entry of the second fluid into the space between tubes ( 2 ) of the tube bundle ( 1 ). 
     
     
         12 . The exchanger according to  claim 7 , wherein the first portion (P 1 ) of the deflecting surface ( 9 ) shows a plurality of perforations ( 9 . 1 ) allowing the entry of the second fluid into the space between tubes ( 2 ) of the tube bundle ( 1 ). 
     
     
         13 . The exchanger according to  claim 5 , wherein the deflecting surface ( 9 ) comprises a third portion (P 3 ) configured as a manifold adapted to guide the inlet flow of the second fluid from the inlet of said second fluid towards the first portion (P 1 ) of the deflecting surface ( 9 ). 
     
     
         14 . The exchanger according to  claim 1 , wherein the tubes ( 2 ) of the tube bundle ( 1 ) comprise recesses ( 2 . 2 . 2 ) distributed along the length of the tube ( 2 ) to increase the rate of heat transfer between the first fluid and the wall of the tube ( 2 ). 
     
     
         15 . An EGR system comprising a heat exchanger according to  claim 1 . 
     
     
         16 . An internal combustion engine comprising an EGR system according to  claim 15 .