Heat exchanger

Abstract

A heat exchanger comprises a plurality of flow pipes for a first fluid and an envelope delimiting an internal volume in which the pipes are placed. The envelope has an inlet for a second fluid and an outlet for the second fluid opening into the internal volume. At least one internal grid is arranged between the inlet of the second fluid and the outlet of the second fluid. The internal grid divides the internal volume into a plurality of chambers arranged one after another in a longitudinal direction. The internal grid delimits a passage for the second fluid with an internal surface of the envelope, wherein the or each passage is arranged such that the second fluid circulates in a labyrinthine fashion from the inlet of the second fluid to the outlet of the second fluid via the chambers.

1 . A heat exchanger, comprising:
 a plurality of flow pipes for a first fluid;   an envelope delimiting an internal volume, in which the plurality of flow pipes are placed, wherein the envelope has an inlet for a second fluid and an outlet for the second fluid opening into the internal volume, wherein the inlet) for the second fluid and the outlet for the second fluid are longitudinally offset from one another;   at least one internal grid arranged within the internal volume, longitudinally between the inlet of the second fluid and the outlet ( 9 ) of the second fluid and dividing the internal volume into a plurality of chambers, arranged one after another in a longitudinal direction, wherein the or each internal grid has orifices in which the pipes engage, wherein the at least one or each internal grid has an external peripheral edge, one section of which delimits a passage for the second fluid with an internal surface of the envelope, wherein the or each passage is arranged such that the second fluid circulates in a labyrinthine fashion from the inlet of the second fluid up to the outlet of the second fluid via the plurality of chambers.   
     
     
         2 . The heat exchanger according to  claim 1 , wherein, for the or each internal grid, the envelope has an area raised towards the outside that delimits the passage from the section of the internal grid. 
     
     
         3 . The heat exchanger according to  claim 1 , wherein, in the at least one or each internal grid, openings are provided between each pipe of the plurality of flow pipes and an internal edge of a corresponding orifice the at least one or each internal grid. 
     
     
         4 . The heat exchanger according to  claim 1 , wherein the plurality of flow pipes each have a transversely elongated cross section and are superimposed in a direction of elevation, wherein internal edges of the orifices carry transverse strips that abut the plurality of flow pipes in the direction of elevation. 
     
     
         5 . The heat exchanger according to  claim 4 , wherein the internal edge of each orifice has two transverse edge sections arranged opposite one another, wherein each transverse edge section carries several transverse strips that are spaced transversely apart from one another. 
     
     
         6 . The heat exchanger according to  claim 5 , wherein the orifices of a single internal grid of the at least one internal grid are separated by full transverse bands of the single internal grid, wherein the full transverse bands each define two transverse edge sections of the orifice, wherein the transverse strips of the two transverse edge sections are staggered. 
     
     
         7 . The heat exchanger according to  claim 4 , wherein the transverse strips are inclined towards an inside of the orifice. 
     
     
         8 . The heat exchanger according to  claim 4 , wherein the outer peripheral edge of the or each internal grid has first and second full bands that extend on either side of the orifices in a transverse direction, wherein the first full band defines the section of the outer peripheral edge and has a width in the transverse direction that is smaller than that of the second full band. 
     
     
         9 . The heat exchanger according to  claim 8 , wherein the at least one or each internal grid comprises several internal grids that are all identical, wherein two consecutive internal grids are orientated inversely in the longitudinal direction such that the first full bands of the two internal grids are inversely turned in the transverse direction. 
     
     
         10 . The heat exchanger according to  claim 9 , wherein the internal grid nearest to the outlet of the second fluid is orientated with the second full band turned towards the outlet of the second fluid, wherein the envelope has at least one intermediate area that is raised towards the outside opposite an intermediate section of the outer peripheral edge arranged between the first full band and the second full band. 
     
     
         11 . The heat exchanger according to  claim 1 , wherein the outer peripheral edge of the at least one or each internal grid carries external strips that abut the internal surface of the envelope. 
     
     
         12 . An exhaust line including the heat exchanger according to  claim 1 , wherein the first fluid is exhaust gas and the second fluid is a coolant provided in order to recover part of thermal energy of the exhaust gas. 
     
     
         13 . A vehicle including the exhaust line according to  claim 12 .