Abstract: The present invention relates to a heat exchanger for exchanging heat between first and second fluids, said exchanger including: a casing and an exchange bundle positioned inside said casing, wherein the exchange bundle includes: a main surface which has a main width and which consists of a plurality of tubes suitable for guiding the first fluid inside said tubes; an intake of the first fluid toward an outlet of the first fluid, making it possible to guide, outside of said tubes, the second fluid; an intake of the second fluid toward an outlet of the second fluid; wherein the tubes are, at least at one first end, assembled such as to form a secondary surface having a secondary width which is smaller than the main width for coupling with the intake and/or the outlet of the first fluid; wherein the secondary surface at the first end of the tubes is formed such as to create a space between the casing and the outer surface of the secondary surface, said space being connected to the intake and/or the outlet of the

Abstract: A heat exchanger (1) for gas, in particular the exhaust gases of an engine, comprising a bundle of tubes arranged inside a shell (2) and intended for the circulation of gas with an exchange of heat with at least one stream of refrigerant fluid, said tubes being fixed by their ends between two support plates (5) coupled at each end of the shell (2), and deflection means arranged inside the shell (2) able to direct the at least one stream of refrigerant fluid inside the shell (2). The deflection means comprises a longitudinal deflector (6, 6a) substantially parallel to the tube bundle and intended to divide the shell (2) into two circuits, said deflector (6, 6a) being fixed by its longitudinal edges to the internal walls of the shell (2) and by its transverse edges to the two support plates (5) by welding. This ensures more effective mounting of said deflector inside the exchanger.