FR2915792A1 - HEAT EXCHANGER EXTRUDE - Google Patents

Abstract

The present invention relates to a heat exchanger (1) having channels / ducts (3, 3 ', 4, 4') for exchanging heat between two fluids, comprising at least one longitudinal central body (2) extruded forming least partly the channels / ducts (3, 3 ', 4, 4') and at least one lateral flank (7 or 8) for closing laterally at least one of said channels / ducts (3, 3 ', 4, 4) ') of said body (2).

Description

RFR0391

  Title: Extruded heat exchanger 5

  The present invention relates to the field of heat exchangers for exchanging heat between two fluids for automotive vehicles, and more particularly to heat exchangers used to recirculate the exhaust gases of the engines of these vehicles, also commonly called EGR (Exhaust Gas Recirculation).

  An exhaust gas recirculation circuit of the engine of a motor vehicle (commonly called EGR for Exhaust Gas Recirculation) extends between the exhaust system of the engine and the intake circuit and generally comprises a heat exchanger thermal system for cooling the exhaust gas, an uncooled bypass channel, a bypass valve for selectively directing the gas flow into the heat exchanger or the bypass duct, and a control valve for adjusting the flow rate of the gas stream in the recirculation circuit.

  A first type of this type of heat exchanger is known at present, comprising a body with tubes received in an outer casing whose ends are connected to flanges for connection to the circuit. Such an exchanger comprises a large number of brazed parts to each other, which makes such a heat exchanger complex and expensive to manufacture. Heat exchangers of the type comprising an outer casing having ends provided with connecting flanges and receiving two molded and contiguous half-shells provided with internal fins to facilitate the heat exchange between, on the one hand, the fluid, are also known. to cool circulating between the fins and, on the other hand, the heat transfer fluid flowing between the outer shell and the half-shells. There are other molded structures having a superposition of channels alternately assigned to transport the fluid to be cooled and the heat transfer fluid. These structures have a reduced number of parts but are expensive to achieve.

  In addition to the essential disadvantage of the cost of manufacture / assembly of these types of heat exchanger, these heat exchangers have a low performance and a significant risk of fouling. The present invention intends to overcome the disadvantages of existing heat exchangers and in particular for the treatment of exhaust gases.

  Thus, the invention relates to a heat exchanger having channels / ducts for exchanging heat between two fluids, comprising at least one extruded longitudinal central body forming at least in part the channels / ducts and at least one lateral flank for closing at least one of said channels / conduits of said body laterally. Extruded expression means that the central body is an element obtained by the extrusion technique. It will be noted that the central body is a metallic material, for example aluminum.

  Thanks to the invention, there is at least one extruded central body of dimensions and shape that is particularly inexpensive to obtain and which allows a complementary work of its surfaces before adding at least one lateral flank to close the channel (s). the heat exchanger. Furthermore, the heat exchanger according to the invention allows a flow of the two fluids in the same direction (and not the same direction) in the channels / ducts.

  Indeed, the invention makes it possible to achieve a significant specific power density, or much greater than that of heat exchangers of the prior art, in particular by adding secondary surface (reported or worked on the very surface of the body central and / or the flank (s)), by a particular method of architecture or cross flow.

  Other features or characteristics are presented in the following: the lateral flank extends over the entire length of the central extruded body, the lateral flank extends from one end, or face (inlet or outlet), the extruded central body, the heat exchanger comprises at least two lateral flanks for closing said body laterally; - The flank (s) is / are fixed (s) to the central body by brazing / welding, gluing or clipping; - The central body comprises at least one conduit / closed channel and at least one open channel; the open channel being closed by the flank. The expression channel / open channel is understood to mean a channel / duct of which only the association of central body with one of the flanks makes it possible to close said channel / duct so that the latter has only two openings on the front face and the back side of the central body / heat exchanger. - According to a possibility 3Q offered by the invention, the central body comprises only ducts / open channels, these channels / ducts being closed by the sidewall and / or by an upper / lower wall. Thus, the invention allows the treatment of the internal surfaces of these channels / open ducts, before the fixing of the flank (s), in particular for a protection of its surface against the fumes / acidic liquids of the exhaust gas. the closed duct is intended for the circulation of a liquid; the open duct is intended for the circulation of a gas; the conduit / open channel comprises at least partly a means forming a secondary surface; the secondary surface means consists of fins or a disruptor; the central body comprises an upper wall and / or a lower wall. the heat exchanger also comprises a casing at least 15 intended to form the inlet channel and the outlet channel of the exchanger; said housing being made of one or more pieces.

  An embodiment of the invention will be described hereinafter, by way of non-limiting example, with reference to the accompanying drawings in which: - Figure 1 shows a perspective view of a heat exchanger according to the invention; FIG. 2 represents a perspective view of another heat exchanger according to the invention; FIG. 3 illustrates, as in the previous figures, a third embodiment of a heat exchanger according to the invention; - Figure 4 illustrates a portion of a central body and that of a sidewall to present a way to fix a sidewall and a way of working the surface of the ducts of said exchanger; Figure 5 illustrates a portion of a central body, the surface of which is worked, and a sidewall according to the invention; FIG. 6 illustrates a way of increasing the exchange surface of a pipe, here by incorporating a turbulator into the central body; FIG. 7 illustrates an example of inserts that can be placed in a duct of the central body; FIG. 8 illustrates a portion of a conduit of a central body in which an insert has been placed.

  The present invention is described here for a use particularly adapted to a fluid exchanger which one of the fluids consists of the exhaust gas of the vehicle but it is understood that its realization and mounting concepts can be envisaged especially for all other types of heat exchangers, or even more generally for producing a module intended for the circulation of at least two fluids.

  It will be noted, however, that one skilled in the art considered for the present invention is a technician in the field of heat exchangers for motor vehicles, and more particularly heat exchangers for heat treating the exhaust gases.

  FIG. 1 shows a heat exchanger 1 for exhaust gas comprising an extruded central body 2 defining a plurality of ducts 3, 3 ', 4, 4', some 3, 3 'intended for the circulation of exhaust gases and others 4, 4 'for the circulation of the fluid used to cool these gases. This heat exchanger 1 has a front face 5 visible in FIG. 1, like FIGS. 2 and 3, as well as a rear face 6, these two faces 5, 6 being open until they are put in place and fixing the front and rear collectors, or respectively inlet and outlet, not shown in the accompanying figures, intended respectively to close each of these faces 5, 6 and form the inlet chamber and the outlet chamber of a fluids, here the (s) exhaust gas.

  In this example chosen to illustrate the invention, in addition to the central body 2, the heat exchanger 1 comprises two lateral flanks 7, 8 and two walls, one upper 9 and the other lower 10. According to a variant, the central body 2 may comprise these upper 9 and lower 10 walls, in this case, the central body 2 intrinsically present an upper wall 9 and lower 10 identical to what is visible in particular in Figures 4 and 6. In this embodiment, it is noted that some of the ducts 4, 4 'of the central body are closed, that is to say that these ducts are open only on the front faces 5 and rear 6.

  According to the embodiment of the extruded central body 2 shown in FIG. 1, all the ducts 3, 3 ', 4, 4' are open, that is to say that they have a lateral face (4 lateral faces: the two sides 7, 8, and the two upper walls 9 and bottom 10) without wall. By fixing the two sidewalls 7, 8 and the upper 9 and lower 10 walls, the central body 2 has two types of ducts, one 4, 4 'of T-shaped section and the other 3, 3' of shaped section. square or rectangular. The top 9 and bottom walls 10 each comprise an opening or recess 11, 12 intended to allow the passage of one of the fluids, here glycol water (engine cooling water) which can flow in one of the two types of ducts, here the two ducts of T-section 4, 4 '. The brine enters the opening 11 located on the upper face 9 of the heat exchanger 1, flows in the direction FI in the conduit 4 and, thanks to a junction opening, not shown in the accompanying figures, between the two ducts 4, 4 ', in the duct 4' in the direction F2. Thus, the coolant carries a U-shaped circulation in the linear direction Oy.

  In this example, the exhaust gases flow through the ducts of the second type 3, 3 'in a single pass, that is to say by entering through one of the faces 5 or 6 of the heat exchanger 1. passing through said heat exchanger 1 and then coming out directly through the opposite face 5 or 6, for example the front face 5. It is also possible to carry out a U-shaped circulation for the exhaust gases, for example against the flow current F1 / F2 of the coolant, through the inlet and outlet manifolds, not shown in the accompanying figures. Thus, the circulation of the second fluid, namely here the (s) exhaust gas, will be U and flowing in the opposite direction / inverse to F1 in the respective ducts 3, 4 and in the opposite direction / inverse to F2 in the respective ducts 3 ', 4'.

  In FIG. 2, the differences with the embodiment illustrated in FIG. 1 lies in the fact that the extruded central body 2 comprises the upper and lower walls 9, so that in this embodiment all the ducts 3, 3 ', 4, 4 'are open only on one of their faces (excluding the faces defined as the front / entry and rear / exit faces), subsequently closed by one or other of the two sides 7 or 8.

  In this embodiment, there are always two types of ducts 3, 3 'and 4, 4' respectively for each of the fluids.

  The first type of duct 4, 4 'has an E-shaped section and is used in this example for the circulation of the coolant. In this example, the inlet orifice 11 of the coolant is located in the upper wall 9 and allows direct communication with a first conduit 4, which is itself in communication, or communication (s) is not not shown (s) or visible in the accompanying figures, with the second duct 4 'of the first type. The outlet orifice 12 is located here in the bottom wall 10 and allows direct communication with the second duct 4 '. Circulation of the fluid flowing in this first type of ducts 4, 4 'is ideally in two passes or U in the direction Oy.30 The second type of ducts 3, 3' is here identical to the second type of ducts 3, 3 ' represented on the heat exchanger 1 of FIG. 1, that is to say that they consist of ducts of square or rectangular section and the circulation is also in two passes or in U. The circulation of the gases of exhaust is here in this type of ducts 3, 3 ', this circulation can be against the direction of circulation or in the same direction of circulation as the coolant, and this depending on the shape and function of the collector and the output manifold (the inlet manifold can perform the function of the outlet manifold, hermetically separating the inlet and outlet chambers while then the so-called outlet manifold will be an intermediate manifold) , not shown in the appended figures; the realization of a flow against the current or in the same direction (for the two passes of each of the fluids) being perfectly known to those skilled in the art. It will be noted that what is referred to as an inlet and outlet manifold is also designated as a casing, intended generally to form / constitute in particular the inlet and outlet channel of the heat exchanger 1.

  FIG. 3 illustrates an embodiment in which the central body 2 again comprises the upper 9 and lower 10 walls and the configuration of the ducts 3, 3 ', 4, 4' and identical to that shown and described in connection with the 1. In this example, the heat exchanger 1 comprises a partition wall 13 located substantially in the middle of the central body 2 / exchanger 1, so that the circulation of the fluid, here the coolant , is carried out according to a U, this U extending in the vertical direction Oz unlike the U-shaped circulation of the embodiments of Figures 1 and 2 in which the U-shaped circulation extend in the horizontal direction Oy. separation 13 is ideally reported following the extrusion of the central body 2 and fixed, for example by brazing, inside a duct 4 of the first type, of T-shaped section.

  The second fluid, here the exhaust gas, circulates identically to the embodiments shown and described in relation to FIGS. 1 and 2 so that in this embodiment of the heat exchanger 1, the circulations of the two fluids do not neither in the same direction nor in the same direction, here respectively the direction Oz for the coolant and the direction Oy for the exhaust gases.

  FIGS. 4 to 8 show different ways of increasing the internal exchange surfaces of the ducts 3, 3 ', 4, 4', this being made possible thanks to the production of a central extruded body 2, sometimes with ducts open (on at least one lateral face 7, 8 or greater 9 / lower 10) for directly working their internal surfaces or with closed ducts (having openings only on the front / entry 15 and rear / exit faces) making it possible to dispose of ancillary means for increasing the exchange surface.

  FIG. 4 shows an example of an open conduit of a central body 2 according to the invention. In this example, an inner face 14 of a conduit 20 3 comprises an increase in its exchange surface which is obtained directly by extrusion, during the production of the central body 2 or can be obtained independently of obtaining the body central 2, for example by clamping, rolling, machining, stamping or punching. Moreover, this FIG. 4 shows a flank 7 which comprises a horizontal wall 16 whose exchange surface is increased 15, identical to the internal surface 14 of the duct 3 formed by the walls of the central body 2. Of course one or more or all internal surfaces of the conduits 3, 3 ', 4, 4' may have an increased or improved exchange surface 15.

  Furthermore, the flank 7 shown has a holding clip 17 intended to cooperate with a longitudinal groove 18 present in the upper wall 9, on its outer face. The holding clip 17 of the sidewall 7 is positioned in the groove 18 when the sidewall 7 is brought into contact with the central body 2. In addition, the fixing of the sidewall 7 by this holding clip 7, which is optional, the fixing of the flank (s) 7 or 8 on the central body 2 is executed by brazing / welding or gluing. In the case of a solder attachment, the brazing material can be disposed only on the contact surface, or internal surface, of the flank (s) 7; the whole of the heat exchanger 1 being formed, by fixing the different elements together, during brazing in the brazing furnace.

  FIG. 5 illustrates a wall 18 of a duct of the central body 2 whose exchange surface is increased 15, by punching, by the use of a knife, by stamping or machining, while the flank 7 represented always comprises a holding clip 17 and extends linearly, that is to say in a plane, without having a part or complementary partition of a duct 3 or 3 '.

  In FIG. 6, the duct 3 illustrated does not have an exchange surface increased by a particular work carried out on the internal surface (s) of the duct 3 but by the incorporation, or the arrangement, of a turbulator 19. This turbulator 19 is fixed to the walls of the wall of the duct 3 in which it is placed for example by brazing its vertices on one or more internal surfaces 14 of the duct 3.

  FIG. 7 illustrates an example of spacer 20 that can be placed inside a duct of the central body 2. This spacer 20 can also be obtained by extrusion, like the central body 2, from the flanks 7, 8 and possibly upper and lower walls 9 and 10.

  Finally, FIG. 8 illustrates an insert or spacer piece 21 adapted to be disposed in a duct 3 of the central body 2, always with the aim in particular of increasing the heat exchange surface of the duct 3.

  It will be noted that the inlet and outlet orifices 11 and 12 present on the upper wall 9 and / or bottom 10 are obtained by cutting, milling or other known technique. Furthermore, the reported flanks 7, 8 and / or the upper and lower walls 9 and 9 may also be obtained by extrusion, identical to the central body 2.

  Those skilled in the art can apply the concepts described to many other similar systems, by combining the various embodiments and embodiments described above, without departing from the scope of the invention defined in the appended claims.

Claims (13)

claims   Heat exchanger (1) having channels / conduits (3, 3 ', 4, 4') for exchanging heat between two fluids, comprising at least one extruded longitudinal central body (2) forming at least in part the channels / ducts (3, 3 ', 4, 4') and at least one lateral flank (7 or 8) for closing laterally at least one of said channels / ducts (3, 3 ', 4, 4') of said body (2).   2. heat exchanger (1) according to claim 1, characterized in that it comprises at least two side flanks (7, 8) for closing laterally said body (2).   3. heat exchanger (1) according to claim 1 or 2, characterized in that the flank (s) (7 and / or 8) is / are fixed (s) to the central body (2) by 1.5 soldering / welding, gluing and / or clipping.   4. Heat exchanger (1) according to any one of the preceding claims, characterized in that the central body (2) comprises at least one duct / closed channel (4 or 4 ') and at least one open channel (3, 3 ', 4, 4'); the open channel (3, 3 ', 4, 4') being closed by the side (7 or 8).   5. heat exchanger (1) according to the preceding claim, characterized in that the closed conduit (4 or 4 ') is intended for the circulation of a liquid. 25   6. Heat exchanger (1) according to claim 4, characterized in that the open conduit (3, 3 ', 4 or 4') is intended for the circulation of a gas.   7. Heat exchanger (1) according to claim 4 or 6, characterized in that the duct / open channel (3, 3 ', 4 or 4') comprises at least partly a secondary surface means (15, 19). , 20, 21). 12   8. heat exchanger (1) according to any one of claims 1 to 3, characterized in that the central body (2) comprises only ducts / open channels (3, 3 ', 4 or 4'); these channels / ducts (3, 3 ', 4 or 4') being formed by the flank (7 or 8) and / or by an upper wall 9 / lower 10.   9. Heat exchanger (1) according to the preceding claim, characterized in that the central body (2) comprises an upper wall (9) and / or a bottom wall (10).   10. Heat exchanger (1) according to claim 7, characterized in that the secondary surface means (19, 20, 21) consists of fins / spacers or a disruptor. 15   11. heat exchanger (1) according to any one of the preceding claims, characterized in that it also comprises a casing at least for forming the inlet channel and the outlet of the exchanger; said housing being made of one or more pieces. 20   12. Heat exchanger (1) according to any one of the preceding claims, characterized in that the lateral flank (7 or 8) extends over the entire length of the central extruded body (2).   13. Heat exchanger (1) according to any one of the preceding claims, characterized in that the lateral flank (7 or 8) extends from an end, or face of entry or exit, of the extruded central body (2) .10