FR2859239A1 - THERMAL CONTROL DEVICE FOR EXHAUST GAS - Google Patents

Abstract

The regulating device of the invention comprises a heat exchanger (5) having an inlet (4) and an outlet (18) for gases flowing along an exhaust line, a bypass (2) capable of being passing through said gases, distribution means (26) for transmitting the gases, either via the bypass (2), or via the heat exchanger (5), or shared between these two directions, the device comprising a housing (3, 19, 24) accommodating at least the distribution means (26) and the bypass (2), the inlet (4) and / or the outlet (18) of the exchanger of heat being located on the surface of said housing. Application to the thermal regulation of exhaust gases of motor vehicles.

Description

Thermal exhaust gas control device

  The invention relates to thermal regulation devices for gas flowing along an exhaust line at the output of thermal engines of motor vehicles.

  Environmental standards impose a significant reduction in the emission levels of internal combustion engines of motor vehicles.

  In order to reduce the formation of nitrogen oxides, thermal exhaust control devices are known which come out of a heat engine and go to a catalytic element of the type known under the designation "DENOX" and capable of reducing the nitrogen oxide content. These devices include a heat exchanger with an external bypass that allows the gas to reach the correct temperature in the catalyst. The gases pass either in the exchanger to be cooled, or in the bypass to not be cooled.

  The main disadvantage of an external bypass is its bulk.

  The invention relates to a device for thermal control of vehicle engine exhaust gas that overcomes this disadvantage through the presence of an internal bypass heat exchanger.

  This object is achieved, according to the invention, by the fact that the device for thermal regulation of gas flowing along an exhaust line of a heat engine comprises: a heat exchanger having an inlet and an outlet for gases; a branch capable of being traversed by said gases; distribution means for transmitting the gases, either via the bypass, or via the heat exchanger, or in a manner shared between these two directions, said device comprising a housing accommodating at least said means distribution and said bypass, the inlet and / or outlet of said heat exchanger being located on the surface of said housing.

  Thus for the exhaust gas, the catalytic element can be used in a wide range of temperatures, or whatever the temperature of the exhaust gas, which makes it possible to operate the lean-burn engine more often, or even whenever this is desirable to reduce fuel consumption.

  Preferably, the heat exchanger and the bypass have at least one communication orifice allowing the introduction of the exhaust gases into said heat exchanger from said bypass.

  In a preferred embodiment of the invention, the bypass is in the form of a central bypass tube coupled by a first end to the input of the regulating device to be fed by the engine exhaust gases. , a transfer tube surrounding the central bypass tube over at least a part of its length to transfer the exhaust gas flowing in the vicinity of a second end of the central tube into the heat exchanger disposed around the transfer tube.

  Thanks to these characteristics, the heat exchanger makes it possible to cool the exhaust gases that pass through it efficiently, without significantly lowering the temperature of the exhaust gases circulating inside the bypass that is located. separated from the exchanger cooling circuit.

  It should also be noted that such a device may, according to the invention, be applied to the thermal regulation of any type of gas, in particular recirculated exhaust gas at the engine intake.

  The bypass means are then coupled between the second end of the central bypass tube and an outlet of the exhaust gas of the regulating device for transmitting the gases leaving the second end of the central bypass tube, or directly to the exhaust outlet of the regulating device when the diverting means are in an open position, or indirectly to the outlet of the exhaust gas of the regulating device via the heat exchanger connected to the transfer tube, when the branching means are in a closed position, or shared between these two directions when the branching means are in an intermediate position between the open position and the closed position.

  According to another important characteristic of the invention, the central bypass tube is traversed in the vicinity of its second end by openings which put the interior of the central bypass tube into communication with the transfer tube.

  This arrangement makes it possible to prevent the gases from entering the heat exchanger when the bypass means (usually a valve) are in a fully open position. To do this, the openings of the central tube are located very close to the second end of the central tube, which allows the pressure of the exhaust gas to drop before and after the passage of the distribution means (usually a valve body) , and make negligible gas leaks to the heat exchanger.

  According to yet another characteristic of the invention, the heat exchanger comprises a beam formed of a multiplicity of parallel tubes arranged all around the transfer tube and assembled with the transfer tube, between a first and a second collecting box with which they communicate, the assembly formed by the transfer tube, the bundle of tubes and the manifolds being traversed by the exhaust gases passing through the openings of the central bypass tube located near its second end, while the bundle of tubes is cooled by a coolant circulating in the space left free between the tubes of the bundle.

  When the valve is completely closed, the exhaust gas passes through the openings at the second end of the central bypass tube and flows between the walls of the central bypass tube and the transfer tube towards the first manifold of the heat exchanger where they penetrate to distribute through tubes of the tube bundle. During their passage through the tubes of the bundle, the exhaust gases are cooled by the coolant which bathes the bundle of tubes before being directed towards the output of the regulating device.

  According to another characteristic of the invention, the first manifold consists of an annular flange on which a cylindrical wall depends, while the first manifold is closed by a cover into which the ends of the tubes of the bundle and a first end transfer tube.

  Advantageously, the second collecting box is formed projecting around a first end of a sleeve in which is engaged the second end of the central bypass tube and comprises a bottom delimited by a cylindrical wall of the sleeve in which the second end is engaged. of the central tube, and a second cylindrical wall surrounding the cylindrical wall of the sleeve, while the second header is closed by a cover in which the ends of the tubes of the bundle open.

  The bottom of the second manifold preferably has an annular opening centered on the longitudinal axis of the central bypass tube which communicates the interior of the second manifold with a trunk-shaped exhaust outlet box. cone, connected by its larger base to the second header, the smaller base having an outlet through which exhaust gas exiting the regulating device.

  In a preferred embodiment, the dispensing means comprise a valve body having an inlet port coupled to the sleeve and an outlet port, opposite the inlet port, opening into the gas outlet box. exhaust.

  The distribution means advantageously comprise a valve coupled between the heat exchanger and the bypass for transmitting the exhaust gas, either directly from the inlet to the outlet when the valve is in the open position, or indirectly to the outlet via the intermediate of the heat exchanger when the valve is in the closed position, is shared between these two directions when the valve is in an intermediate position between the open position and the closed position.

  In the invention, the heat exchanger is advantageously cooled by a mixture of water and glycol.

  It is furthermore advantageous that the sections of the exhaust gas flows in the central tube and in the circuit formed by the transfer tube and the heat exchanger are approximately constant.

  In another embodiment of the invention, the bypass is in the form of a straight tube extending between an inlet and an outlet of the regulating device, while the gas circulation circuit in the heat exchanger heat has a U-shape and communicates with the bypass tube, respectively with an upstream intersection on the inlet side and a downstream intersection on the outlet side, the bypass means being coupled between the bypass tube and the diverter box. heat exchange.

  In this second embodiment of the invention, the derivation means advantageously comprise a butterfly type valve housed in the branch tube between the upstream intersection and the downstream intersection.

  In a third embodiment, the branch is in the form of a straight tube extending between an inlet and an outlet of the device, while the heat exchanger is made in the form of plates or tubes parallel to the longitudinal direction of the tube forming the bypass and communicating with the tube forming the bypass respectively with an upstream intersection on the input side and a downstream intersection on the outlet side, the distribution means being coupled between the bypass tube and the heat exchanger.

  In a fourth and fifth embodiment the heat exchanger, the bypass and the distribution means are enclosed in the same housing. The heat exchanger is formed by two half-bundles of parallel plates or tubes composed of two parallel blocks in the form of rectangular parallelepipeds disposed on either side of the same branch duct extending between an inlet and a exit from the case. The valve is pivotally mounted in the bypass duct.

  The blocks are kept separated inside the casing between two parallel plates respectively forming the bottom and the cover of the casing, while the bypass duct is delimited by the space between the two plates and by the lateral faces facing each other. opposite the two blocks.

  In the fourth embodiment each half-beam is constituted by plates traversed by a coolant, separated from each other by spaces or interstices which communicate directly with the bypass duct.

  In the fifth embodiment, each half-beam consists of tubes parallel to the longitudinal axis of the duct which communicate at their respective ends with the bypass duct through an inlet manifold and a outlet manifold nested on the outer faces of the housing around the ends of the bypass duct.

  All the previously described configurations make it possible to obtain a reduced space integration of the device. this facilitates the temperature rise of the DENOX catalytic element, which can reach very quickly its operating point around 250 C necessary to obtain an effective reduction of the nitrogen oxide content when the valve in the conduit or the bypass tube is in the open position.

  Of course, other embodiments are possible, from the moment when the device comprises an internal bypass associated with a heat exchanger, the internal bypass and the heat exchanger being mounted between the inlet and the outlet of the device. .

  In another aspect, the invention relates to an exhaust gas circulation system for a heat engine, this installation comprising a thermal exhaust gas control device as defined above.

  The regulating device is advantageously interposed between a three-way catalyst and a catalytic element, in particular of the "Denox" type.

  Other features and advantages of the invention will become apparent upon reading the description which follows with reference to the appended figures. In these figures: FIG 1 is a schematic sectional view of an exemplary embodiment of a thermal exhaust gas control device according to the invention; FIG. 2 is an external front view of the thermal regulation device of FIG. 1; - Figure 3 is a diagram of an installation comprising a control device according to the invention interposed between a three-way catalyst and a catalytic element; FIG. 4 is a sectional view of a thermal regulation device according to a second embodiment of the invention, interposed between a three-way catalyst and a catalytic element; - Figures 5 and 6 are a sectional view and a perspective view of a thermal control device according to a third embodiment of the invention comprising a heat exchanger formed by a parallel plate bundle; FIGS. 7 and 8 are cross-sectional views of a thermal regulation device according to a fourth and fifth embodiment of the invention respectively comprising a heat exchanger formed by a parallel plate bundle and a bundle of parallel tubes. ; - Figure 9 an exploded view of a thermal control device according to the fourth embodiment of the invention; FIGS. 10 and 11 are two perspective views of the thermal control device of FIG. 9, in the mounted state, showing the flow path of the gases in the device when the valve of the distribution circuit is respectively in the open position. and in the closed position; FIG. 12 is a perspective view of a thermal control device according to the fifth embodiment showing the flow path of the gases in the device when the dispensing valve is in the open position; - Figure 13 is a perspective view of a thermal control device according to the fifth embodiment showing the flow path of the gas in the device when the valve is in the closed position; and FIG. 14 is a perspective view of a thermal control device according to the fifth embodiment showing the cooling circuit of the device.

  The thermal exhaust gas control device, which is designated by the reference 1 in Figure 1, is more particularly intended to operate in connection with a motor vehicle engine.

  The regulating device 1 comprises a central bypass tube 2 with a longitudinal axis XX 'whose first end is engaged in a gas inlet flange 3. The wall of the central bypass tube 2 is traversed in the vicinity of the second end of the tube through openings 4 which connect the interior of the central bypass tube 2 with a heat exchanger 5 via a transfer tube 6 surrounding the central branch tube 2 over part of its length. The openings 4 thus constitute the inlet of the heat exchanger 5.

  The heat exchanger 5 is formed in known manner by a beam formed of a multiplicity of parallel tubes 7 arranged all around the transfer tube 6 in a direction parallel to the axis XX 'and assembled with the transfer tube 6, between a first manifold 8 and a second manifold 9 with which they communicate so that the assembly formed by the transfer tube 6, the bundle of tubes 7 and the manifolds 8 and 9 folds to be traversed by the gases of exhaust.

  The first manifold 8 consists of an annular flange 10 on which a cylindrical wall 11 depends. The first manifold 8 is closed by a cover 12, forming a collector, in which the ends of the tubes 7 of the bundle open and a first end of the transfer tube 6. The first manifold 8 is fixed by screws 13 against the gas inlet flange 3.

  The second manifold 9 is formed projecting around a first end of a sleeve 14 in which is engaged the second end of the central bypass tube 2. It consists of a bottom 15 delimited by a cylindrical wall 16 of the sleeve 14 in which is engaged the end of the central bypass tube 2, and a second cylindrical wall 17 surrounding the cylindrical wall 16 of the sleeve. The second manifold 9 is closed by a cover 18 forming a collector into which the ends of the tubes 7 of the bundle open. The lid 18 thus forms the outlet of the heat exchanger.

  The bundle of parallel tubes 7 is disposed inside a cylindrical wall 19 concentric with the central bypass tube 2, closed at its ends by the covers 12 and 18 of the manifolds 8 and 9 and is cooled by a coolant such as for example, a mixture of water and glycol, from the engine cooling circuit, not shown. The coolant enters the space left free between the tubes 7 of the bundle and the space defined by the cylindrical wall 19 and the covers 12 and 18 of the manifolds 8 and 9, by an intake manifold 20 and a manifold 21 (Figure 2) connected to the engine cooling circuit. The lid 18 thus constitutes the outlet of the heat exchanger 5.

  The bottom 15 of the second header 9 has an annular opening 22 defined by two circular edges centered on the longitudinal axis XX 'of the central bypass tube 2. The annular opening 22 communicates the interior of the second header 9 with an exhaust outlet box 24, which has a flange 23 for attachment to the manifold 9. The outlet box 24 has the shape of a truncated cone and is connected by its larger base to the manifold 9, the smallest base having an outlet 25 through which the exhaust gas exiting the regulating device 1 escapes.

  The sleeve 14 also communicates the central bypass tube 2 with the outlet box 24 of the exhaust gas via a valve 26 provided with a valve 27 and whose body has an inlet port 28. coupled to the sleeve 14 and an outlet orifice 29, opposite the inlet orifice 28, opening opposite the outlet orifice 25. The body of the valve has the shape of a cylinder centered on the axis XX and it is connected to the outlet box 24 by a diametrical spacer 30.

  The valve 27 is rotated by an actuator 31, for example a pneumatic valve, shown in FIG. 2, and makes it possible to control the temperature of the exhaust gases leaving through the orifice 25 of the outlet box 24.

  The regulating device comprises a housing, formed here by the gas inlet flange 3, the cylindrical wall 19 and the outlet box 24. This housing accommodates at least the distribution means, ie here the valve 26 , and the bypass 2. The inlet 4 and / or the outlet 18 of the heat exchanger are located on the surface of said housing.

  Optimum operation of the device which has just been described can be obtained by paying particular attention to the fact that the sections of the exhaust gas flows in the central tube 2 and in the circuit formed by the transfer tube 6 and the heat exchanger. heat 5 are approximately constant, this in order to minimize the pressure losses in the circuits and heat losses in the central tube 2.

  In order to prevent the gases from entering the heat exchanger when the valve 26 is fully open, the openings 4 of the central tube 2 are placed very close to the second end of the central tube, which allows the pressure of the gases exhaust before and after passing through the valve body, and greatly limit gas leakage to the heat exchanger 5. In this way, when the valve 27 is fully open, the exhaust gases that arrive by the intake flange 3 are directed through the central bypass duct 2 and the valve body 26 directly to the outlet manifold 24.

  When the valve 27 is completely closed, the exhaust gas passes through the openings 4 situated at the second end of the central bypass tube 2 and circulates between the wall of the central bypass tube 2 and that of the transfer tube 6 in the direction of the first manifold 8 of the heat exchanger 5 where they penetrate to be distributed through the tubes 7 of the bundle of tubes. During their journey in the tubes 7 of the bundle, the exhaust gases are cooled by the cooling liquid which bathes the bundle of tubes 7, then they are directed towards the outlet box 24.

  When the valve 27 is in an intermediate open position, it can be controlled so as to control the flow of the exhaust gas leaving the valve body 26 and the flow of gas flowing in the heat exchanger 5 to obtain a precise temperature value determined at the outlet in the outlet orifice 25 of the outlet box 24.

  Referring now to Figure 3 which schematically illustrates the integration of a control device 1 according to the invention between a catalyst 32 of the three-way type and a catalyst element 33 of the "Denox" type. The catalyst 32 is connected to the manifold 34 of a heat engine 35 and is thus fed by the exhaust gas of the latter. At the outlet of the catalyst 32, the exhaust gas is cooled to the right temperature by the regulating device of the invention and then sent to the catalytic element 33 which reduces the nitrogen oxide content of the exhaust gases. 'exhaust. These are then evacuated to the outside by a duct 36.

  In the diagram of Figure 3, the control device 1 may be constituted by a control device as shown in Figures 1 and 2, or by another internal bypass regulating device meeting the characteristics of the invention.

  FIG. 4 schematically illustrates another thermal regulation device 1 according to the invention. This device 1 comprises an inlet 37 and an inlet 38 connected respectively to the outlet of a catalyst 32 similar to that of FIG. 3, and to the inlet of a catalytic element 33 similar to that of FIG. also shown in Figure 4 the manifold 34 of the exhaust gas and the pipe 36 which discharges the exhaust gas to the outside.

  In the embodiment of FIG. 4, the shunt here is in the form of a straight tube 39 extending between the inlet 37 and the outlet 38 of the thermal control device.

  The device further comprises a heat exchanger 40 provided with a U-shaped gas circulation circuit communicating with the bypass tube 39, respectively with an upstream intersection 41 on the input side 37 and with a downstream intersection 42 the outlet side 38. The heat exchanger 40 defines two circulation branches 43 and 44 connected by a U-shaped bend 45. An intermediate partition 46 defines the inlet and the outlet of the branches 43 and 44.

  The device 1 of FIG. 4 further comprises a butterfly valve 47 housed in the bypass tube 39 between the upstream intersection and the downstream intersection so as to be coupled between the bypass tube and the exchange tube. heat. This bypass valve is pivotally mounted about an axis 48.

  When the valve is in the open position, the exhaust gases are transmitted directly from the inlet 37 to the outlet 38. When the valve is in the closed position, the exhaust gases are transmitted by the heat exchanger 40. when the valve is in an intermediate position, the exhaust gases are shared between the tube 39 and the heat exchanger 40.

  The regulating device comprises a housing 39 'which, as in the previous embodiment, accommodates at least the distribution means, ie the valve 47 and the bypass 39. The inlet (upstream intersection 41) and / or the outlet (downstream intersection 42) of the heat exchanger are located on the surface of said housing. The cooling liquid circulates in a space 45 'left free between the gas circulation branches 43, 44 and the inner wall of the tube 40.

  FIGS. 5 and 6 illustrate an alternative embodiment of the thermal control device of FIG. 4. This device comprises, like the device of FIG. 4, where the homologous elements bear the same references, a tube-shaped bypass duct 39 distribution means in the form of a butterfly valve valve 47 controlled similarly to the valve 27 of Figure 1 by an actuator 31. The bypass tube 39 acts as the housing 39 'and extends between an inlet 37 and an outlet 38 respectively connected, as shown in FIG. 3, at the outlet of a catalyst 32 similar to that of FIG. 3, and at the inlet of a catalytic element 33 similar to that of Figure 3.

  The device further comprises a heat exchanger 40 communicating with the bypass tube 39 respectively with an upstream intersection branch 41 on the input side 37 and a downstream intersection branch 42 on the output side 38. To limit at the maximum of the pressure drops between the inlet 37 and the outlet 38 of the exchanger, it is advantageous that the sections of the flows in the circuit formed by the bypass tube 39, the upstream and downstream intersection branches 41, 42 and the heat exchanger 40 are approximately constant.

  The heat exchanger 40 is formed, as shown in FIG. 6, of a bundle of plates or tubes 49 parallel to the longitudinal direction of the tube 39 and traversed by a coolant circulating between an inlet orifice 51 and a outlet port 52. To increase the heat output dissipated by the exchanger all or part of the plates 49 may be formed in known manner by turbulence generating plates.

  The valve of the valve 47 is pivotally mounted in the bypass tube 39 between the upstream intersection branch 41 and the downstream intersection branch 42.

  The gas enters the device through the inlet orifice 37 of the tube 39. The temperature regulation is controlled by the valve 47 of the valve. When the valve 47 is in the open position, the exhaust gases are transmitted directly from the inlet 37 to the outlet 38. When the valve 47 is in the closed position, the exhaust gases follow a "C" shaped circuit. . They are transmitted in the heat exchanger 40 by the intersection branch 41 and emerge from the heat exchanger 40 through the intersection branch 42 towards the outlet 38 to enter the catalytic element 38. Finally when the valve is in an intermediate position, the exhaust gases are shared between the tube 39 and the heat exchanger 40.

  Figures 7 to 13 illustrate two other embodiments of a control device according to the invention.

  In these examples, where elements similar to those of Figures 5 and 6 have the same references, the heat exchanger 40, the bypass duct 39 and the distribution means 47 are enclosed in the same housing 39 '. The heat exchanger is constituted by two half-bundles of parallel plates or tubes forming two parallel blocks 40a and 40b in the form of rectangular parallelepipeds disposed on either side of the same branch duct 39 extending partially between the inlet 37 and an outlet 38 of the bypass duct 39, the inlet 37 and the outlet 38 being respectively connected to the outlet of a catalyst 32 similar to that of FIG. 3, and to the inlet of an element catalysis 33 similar to that of Figure 3.

  The blocks 40a, 40b are kept separated inside the housing 39 'between two parallel rectangular plates 53 and 54 respectively forming a bottom wall 53 and a closure wall 54 of the housing 39'. The bypass duct 39 is delimited by the space between the two plates 53 and 54 and by the lateral faces 55 and 56 of the two blocks 40a, 40b facing each other and is extended outside this space by two portions of tubes 57, 58 for connecting the branch duct 39 between the outlet of the catalyst 32 and the inlet of the catalytic element 33.

  The valve 47 of the valve is introduced into the bypass tube 39 through an orifice 47a through the closure plate 54 of the housing 39 'and is held in suspension in the bypass tube by a support plate 47b screwed on the closure plate 54 .

  In FIGS. 7, 9, 10 and 11, the lateral walls 59 to 62 of the housing 39 'are made by folding at right angles to two opposite ends of the plates 53 and 54 and by embedding the folded ends of each plate in the U formed by the folded parts of the other plate. The side walls 59, 60 of the housing 39 ', which are parallel to the bypass duct 39, respectively cover the faces of the blocks 40a, 40b, opposite to the side faces 55, 56 of the two blocks 40a, 40b facing each other. The blocks 40a, 40b can thus be fixed to the housing 39 on the walls of the corresponding dihedral formed by the bottom plate 53 and the side walls 59, 60 parallel to the bypass line 39.

  Each half-beam is constituted by parallel plates 61 stacked above the bottom plate 53 and traversed by a cooling liquid flowing between an inlet pipe 63a and an outlet pipe 63b. The half-beams constituting the blocks 40a and 40b are interconnected by a coolant circulation duct 64. The plates are separated from each other by spaces or interstices 65 which communicate directly with the bypass duct 39.

  As shown in FIG. 10, when the valve 47 of the valve is in the open position, the exhaust gases are transmitted directly from the inlet 37 to the outlet 38. When the valve 47 of the valve is in the closed position as the 11, the exhaust gases are transmitted in the heat exchanger 40 through the interstices 65 of the plates and run through the exchanger 40 a circuit, as shown by the arrows, shaped "0". Finally, when the valve is in an intermediate position, the exhaust gases are shared between the tube 39 and the heat exchanger 40.

  In FIGS. 8, 12 and 13, where the elements homologous to those of FIGS. 7, 9, 10, 11 bear the same references, the housing 39 'comprises a bottom plate 53, a closure plate 54 and two lateral walls. 59, 60 parallel to the longitudinal axis of the bypass duct 39. The side walls 59, 60 of the housing 39 ', parallel to the bypass duct 39 respectively cover the faces of the blocks 40a, 40b opposite the side faces 55, 56 in screws opposite the two blocks 40a, 40b.

  Unlike the previous example, the lateral faces 55, 56 facing the blocks 40a, 40b no longer communicate with the bypass duct 39, but they are isolated from it either by a single plate respectively 66, 67 or by two plates separated by an air knife or a thermally insulating material spaced apart between the bottom wall 53 and the closing wall of the housing 54. The blocks 40a, 40b are fixed to the housing 39 'against the walls of the corresponding dihedral formed by the bottom plate 53 and the side walls 59, 60 parallel to the bypass line 39.

  The ends of the housing 39 'which were covered in FIGS. 9, 10, 11 by the side plates 61, 62 perpendicular to the longitudinal axis of the bypass duct 39 are open and communicate respectively with the inlet and the outlet. of the device through a collector box respectively 68, 69.

  The heat exchanger is constituted by two half-bundles of tubes 70 parallel to the longitudinal axis of the bypass duct 39. The two half-beams communicate by the respective ends of their tubes 70 with the bypass duct 39 by the intermediate of an input manifold 68 in the form of pyramid truncated at its top and an outlet manifold 69 also shaped truncated pyramid at its top.

  The two manifolds 68 and 69 have their large bases nested on the outer faces of the housing 39 'around the ends of the bypass duct 39. They communicate respectively with the inlet 37 and the outlet 38 of the control device via ducts 57, 58 engaged in orifices on the smaller bases of manifolds 68 and 69.

  When the valve 47 of the valve is in the open position, the exhaust gases are transmitted directly from the inlet 37 to the outlet 38 through the bypass duct 39. When the valve 47 of the valve is in the closed position as shown In Figure 9, the exhaust gas is passed into the heat exchanger 40 through the inlet manifold 68 and out through the outlet manifold 69 after following an "O" shaped path. Finally, when the valve 47 of the valve is in an intermediate position, the exhaust gases are shared between the duct 39 and the heat exchanger 40.

  As indicated above, the thermal control device 1 according to the invention can be used in other applications.

Claims (27)

claims   A device for thermal regulation of gas flowing along an exhaust line of a heat engine, comprising: - a heat exchanger (5; 40) having an inlet (4; 41) and an outlet (18; 42) for gases; - a bypass (2; 39) adapted to be traversed by said gases; distribution means (26; 47) for transmitting the gases, either via the bypass (2; 39), or via the heat exchanger (5; 40), or in a shared manner between these two directions, characterized in that said device comprises a housing (3, 19, 24; 39 ') accommodating at least said distribution means (26; 47) and said bypass (2; 39), the inlet (4; 41) and / or outlet (18; 42) of said heat exchanger being located on the surface of said housing.   2. Device according to claim 1, characterized in that the circulation of the gases in the heat exchanger is carried out inside a cylinder (19) concentric with said bypass (2). 3. Device according to one of claims 1 and 2, characterized in that said heat exchanger (5; 40) and said bypass (2; 39) have at least one communication port (4; 41) allowing the introduction exhaust gas in said heat exchanger from said bypass.   4. Device according to one of claims 1 and 3, characterized in that the bypass is formed as a central bypass tube (2), coupled by a first end to the input of the device to be powered by the exhaust gases of the heat engine, in that a transfer tube (6) surrounds the central bypass tube (2) over at least a part of its length to transfer the exhaust gas circulating in the vicinity of a second end of the central tube in the heat exchanger (5) disposed around the transfer tube (6), and in that the distribution means (26) are coupled between the second end of the central bypass tube (2) and an outlet (25) of the exhaust gas of the regulating device (1) for transmitting the gases leaving the second end of the central bypass tube (2), either directly to the outlet (25) of the gases Exhaust regulating device lor sque the distribution means (26) are in an open position, or indirectly to the outlet (25) of the exhaust gas of the regulating device (1) via the heat exchanger (5) connected to the transfer tube (6) when the dispensing means (26) are in a closed position, or shared between these two directions when the dispensing means (26) are in an intermediate position between the open position and the position closed.   5. Device according to claim 4, characterized in that the central bypass tube (2) is traversed in the vicinity of its second end by openings (4) which put in communication the inside of the central bypass tube (2) with the transfer tube (6).   6. Device according to one of claims 4 and 5, characterized in that the heat exchanger (5) comprises a beam formed of a plurality of parallel tubes (7) arranged around the transfer tube (6) and assembled with the transfer tube (6), between a first manifold (8) and a second manifold (9) with which they communicate, the assembly formed by the transfer tube (6), the bundle of tubes (7) ) and the manifolds 8, 9) being traversed by the exhaust gases passing through the openings (4) of the central bypass tube (2) situated in the vicinity of its second end, and in that the bundle of tubes (7) is refrigerated by a coolant circulating in the space left free between the tubes (7) of the beam.   7. Device according to claim 6, characterized in that the first manifold (8) consists of an annular flange (10) on which a cylindrical wall (11) depends, and in that the first manifold (8) is closed by a cover (12) into which the ends of the tubes (7) of the bundle and a first end of the transfer tube (6) 8. Device according to one of claims 6 and 7, characterized in that the second manifold (9) is formed protruding about a first end of a sleeve (14) in which is engaged the second end of the tube central bypass (2) and comprises a bottom (15) delimited by a cylindrical wall (16) of the sleeve (14) in which is engaged the second end of the central tube (2), and a second cylindrical wall (17) surrounding the cylindrical wall (16) of the sleeve (14), and in that the second header (9) is closed by a cover (18) in which the ends of the tubes (7) of the bundle open.   9. Device according to claim 8, characterized in that the bottom (15) of the second header (9) comprises an annular opening (22) centered on the longitudinal axis of the central bypass tube (2) which puts in communication inside the second manifold (9) with a truncated cone-shaped exhaust outlet (24), connected by its larger base to the second manifold (9), the smaller base having an outlet (25) through which the exhaust gases exiting the regulating device (1) escape.   10. Device according to one of claims 8 and 9, characterized in that the dispensing means comprise a valve body (26) having an inlet port (28) coupled to the sleeve (16) and an outlet port ( 29), opposite the inlet port, opening into the exhaust outlet box (24).   11. Device according to one of claims 1 to 10, characterized in that the distribution means comprise a valve (26; 47) coupled between the heat exchanger (5; 40) and the bypass (2; 39) for transmit the exhaust gas either directly from the inlet to the outlet when the valve is in the open position or indirectly to the outlet via the heat exchanger (5; 40) when the valve is in position closed, or shared between these two directions when the valve (26; 47) is in an intermediate position between the open position and the closed position.   12. Device according to one of claims 1 to 11, characterized in that the heat exchanger (5) is cooled by a mixture of water and glycol.   13. Device according to one of claims 10 to 12, characterized in that the sections of the exhaust gas flows in the central tube (2) and in the circuit formed by the transfer tube (6) and the exchanger of heat (5) are approximately constant.   14. Device according to claim 1, characterized in that the bypass is in the form of a straight tube (39) extending between an inlet (37) and an outlet (38) of the device, in that the circuit in the heat exchanger (40) has a "U" shape and communicates with the bypass tube (39), respectively with an upstream intersection (41) on the inlet side (37) and a downstream intersection (42) on the outlet side (38), and in that the distribution means (47) are coupled between the bypass tube and the heat exchange tube.   15. Device according to claim 14, characterized in that the dispensing means comprise a valve (47) of the butterfly type housed in the bypass tube (39) between the upstream intersection (41) and the downstream intersection (42) .   Device according to claim 1, characterized in that the bypass is in the form of a straight tube (39) extending between an inlet (37) and an outlet (38) of the device, and in that the heat exchanger (40) has a "C" shaped gas flow path and is formed as plates or tubes parallel to the longitudinal direction of the right tube forming the bypass and communicate with the bypass tube ( 39), respectively with an upstream intersection (41) on the inlet side and with a downstream intersection (42) on the outlet side, and in that the distribution means (47) are arranged in the bypass tube ( 39) between the upstream intersection (41) and the downstream intersection (42).   17. Device according to claim 1, characterized in that the bypass (39), the heat exchanger (40) and the distribution means (47) are enclosed in the same housing (39 ') and in that the heat exchanger (40) has a "0" shaped gas circulation circuit and is formed by two half-bundles of parallel plates (61) or tubes (70) composed of two parallel blocks (40a, 40b) in rectangular parallelepiped shape disposed on either side of a duct forming the shunt (39).   18. Device according to claim 17, characterized in that the blocks (40a, 40b) are kept separated inside the housing (39 ') between two parallel plates (53,54) respectively forming the bottom (53) and a closing plate (54) of the housing (39 ') and in that the bypass duct (39) is delimited by the space between the two plates (53,54) and the lateral faces (55,56) in vis-à-vis the two blocks (40a, 40b).   19. Device according to one of claims 16 to 18, characterized in that the distribution means comprises a valve (47) pivotally mounted valve in the bypass duct (39).   20. Device according to one of claims 17 to 19, characterized in that each half-beam component blocks (40a, 40b) is constituted by parallel cooling plates (61) separated from each other by spaces or interstices (65) which communicate directly with the bypass duct (39).   21. Device according to one of claims 17 to 19, characterized in that the two half-beams are composed of tubes (70) parallel to the longitudinal axis of the conduit (39) which communicate at their respective ends with the conduit of bypass (39) via an inlet manifold (68) and an outlet manifold (69) nested on the outer faces (53,54,59,60) of the housing (39 ') around the ends of the bypass duct (39).   22. Device according to claim 1, characterized in that the gas circulation circuit in the heat exchanger is formed inside a concentric cylinder (19) to said bypass (2).   23. Device according to claim 1, characterized in that the gas circulation circuit has the shape of a "U", the two ends of the "U" (41,42) being in communication with the ends of said bypass ( 39).   24. Device according to claim 1, characterized in that the gas circulation circuit has the shape of a "C" (40), the two ends of the "C" (41,42) being in communication with the ends of said bypass (39).   25. Device according to claim 1, characterized in that the gas circulation circuit has the form of a "0" crossed by said shunt (39) with which it communicates.   26. Exhaust gas circulation system for a heat engine, characterized in that it comprises a device for thermal regulation of the exhaust gas according to one of claims 1 to 25.   27. Installation according to claim 26, characterized in that the regulating device (1) is interposed between a catalyst (32) with three channels and a catalyst element (33).