WO2008101560A1

WO2008101560A1 - System for orientating a recirculated combustion gas flow

Info

Publication number: WO2008101560A1
Application number: PCT/EP2007/063839
Authority: WO
Inventors: Bernard Rollet
Original assignee: Renault S.A.S.
Priority date: 2007-01-19
Filing date: 2007-12-12
Publication date: 2008-08-28
Also published as: EP2115293B1; FR2911638B1; ATE486210T1; DE602007010186D1; FR2911638A1; EP2115293A1

Abstract

The invention relates to an orientation system (2) that comprises an inlet (10), an outlet (11), two openings (12a, 12b) connected together by an secondary device (1), and an inversion system (13) formed by two devices (14a, 14b) separated from each other and each including a fixed structure (15a, 15b) with a chamber (17a, 17b) leading to the common inlet (10) and outlet (11) and to an independent opening (12a, 12b), and a mobile member (16a, 16b) provided in the chamber (17a, 17b) and capable of movement between a first position, in which the opening (12a, 12b) is isolated from the outlet (11) and communicates with the inlet (10), and a second position in which it is isolated from the inlet (10) and communicates with the outlet (11), wherein one mobile member (16a, 16b) is in one of said positions when the other member (16a, 16b) is in the other position in order to reverse the flow direction in the secondary device (1).

Description

SYSTEM FOR ORIENTING A COMBUSTION GAS STREAM IN

RECIRCULATION

The present invention relates to a system for directing a recirculating flow of combustion gas into an auxiliary device, for example a chiller, of a recirculation circuit of combustion gas.

Such a system of the type comprising a gas inlet opening, a gas outlet opening, two connecting openings adapted to be connected to one another by the cooler, and an inversion system allowing to circulating the gas from the inlet opening, before being discharged through the outlet opening, into the cooler in either direction. Such an orientation system is thus described in the French patent application 05 52 970 of September 30, 2005.

The present invention aims to improve the flow of gases in the orientation system and the impermeability of the orientation system.

According to the invention, the system of the aforementioned type is formed by two orientation devices which are isolated from each other, each comprising, on the one hand, a fixed structure which is specific to it and which comprises a hollow cavity. an orientation leading to the common inlet and outlet openings and to a connection opening of its own, and, on the other hand, a movable member of its own, which is arranged in the corresponding orientation cavity, and which is movable between a first connection position in which it communicates the corresponding connection opening with the inlet opening and isolating it from the outlet opening, and a second connection position in which it communicates the corresponding connection opening with the outlet opening and isolates it from the opening of the two orientation devices being arranged relative to one another so that when the movable member of one of the devices is in one of the two connection positions, that of the other device of orientation is in the other of these two positions. When one of the movable members is in its first connection position, the other movable member is in its second connection position. As a result, the recirculating gases coming from the inlet opening, on the one hand, are forced into the orientation cavity of a first orientation device whose movable member is in its second position. connection

(Insulation of the inlet opening of the first device), and, secondly, flow in the orientation cavity of the second orientation device whose movable member is in its first connection position, then in the connection opening associated with the second orientation device (communication between the inlet opening and the corresponding connecting opening of the second device), in the cooler, in the connection opening associated with the first orientation device and are evacuated through the exit opening (communication between the exit opening and the corresponding connection opening of the first device). By reversing the connection positions of the two movable members, the flow direction of the cooling gases in the cooler are reversed. The present invention therefore effectively cleans all the flue gas circulation lines in the cooler by reversing the coldest end (and therefore the least easily cleaned) of the heat exchanger.

Other features and advantages will appear in the description of two embodiments given by way of non-limiting examples and illustrated in the appended drawings in which: FIG. 1 is a schematic perspective view of a compliant orientation system In the present embodiments of the present invention, the movable members of the two orientation devices are not shown. FIG. 2 is a schematic perspective view of the movable members of the two orientation devices according to a first embodiment.

FIG. 3 is a view similar to FIG. 1, the movable members according to FIG. 2 being shown, the movable member of the foreground orienting device being in its first connection position,

FIG. 4 is a view similar to FIG. 3, the movable member of the orientation device in the foreground being in its second connection position; FIG. 5 is a view similar to FIGS. 3 and 4, the moving member of the foreground orientation device being in an intermediate short-circuit position,

FIG. 6 is a schematic perspective view of the movable members of the two orientation devices according to a second embodiment, FIG. 7 is a view similar to FIG. 3, the movable members shown being those of FIG. 6,

FIG. 8 is a view similar to FIG. 7, the movable member of the foreground orienting device being in its second connection position, and

Figure 9 is a view similar to Figures 7 and 8, the movable member of the orientation device in the foreground being in an intermediate position of short circuit.

As can be seen in the different drawings a flue gas cooling system re ^¬ circulation in an internal combustion engine comprises a cooler 1 and a gas guidance system 2. More specifically, this cooler 1 comprises a beam of gas circulation pipes 3 which is disposed inside an enclosure 4 in which circulates a cooling fluid; as a result, the pipe bundle 3 is immersed in the cooling fluid. Conventionally, in order to allow the circulation of the cooling fluid, the chamber 4 comprises a cooling fluid inlet opening 5 and an outlet opening 6. The use of such a cooler 1 makes it possible to reduce the temperature of the gases recirculated before their introduction into the engine.

In the present embodiments, the cooler 1 is in U in which the two gas circulation ends 8a, 8b are adjacent to each other, the longitudinal ends 8a, 8b being in the same plane. As can be seen particularly in FIG. 1, the orientation system 2 comprises a recirculating gas inlet opening 10, an outlet opening 11 for these same gases, and two connecting openings 12a, 12b which are connected to each other by the cooler 1. Each connecting opening 12a, 12b is connected to a gas circulation end 8a, 8b of the cooler 1 which is specific to it.

The orientation system 2 also comprises an inversion system 13 which makes it possible to circulate in the cooler 1, in one direction as in the other, the gases coming from the inlet opening 10, before discharging them through the exit opening 11.

The inversion system 13 is formed by two orientation devices 14a, 14b which are isolated from each other. Each orientation device 14a, 14b comprises a fixed structure 15a, 15b which is specific to it, and a movable member 16a, 16b which is also specific to it.

Each fixed structure 15, 15b has an orientation cavity 17a, 17b which is its own and which opens at the common inlet opening 10, to the common outlet opening 11 and to a connecting opening 12a, 12b which it's clean.

Each movable member 16a, 16b is disposed in the corresponding orientation cavity 17a, 17b. It is movable between a first connection position in which it communicates the corresponding connection opening 12a, 12b with the common inlet opening 10 and isolates it from the common outlet opening 11, and a second position of connection in which it communicates the corresponding connection opening 12a, 12b with the common opening output 11 and isolates it from the common input opening 10.

Furthermore, the two orientation devices 14a, 14b are arranged relative to each other so that when the movable member 16a, 16b of one of the two orientation devices 14a, 14b is in the one of the two connection positions, the movable member 16b, 16a of the other orientation device 14b, 14a is in the other of these two positions. Thus when a movable member 16a, 16b communicates the corresponding connection opening 12a, 12b with the common inlet opening 10 and isolates it from the common outlet opening 11, the other movable member 16b, 16a makes communicating the corresponding connection opening 12b, 12a with the common outlet opening 11 and isolating it from the common inlet opening 10.

As a result, the recirculating gases arrive at the inverting system 13 through the inlet opening 10 and then circulate to meet the movable members 16a, 16b.

The gases meeting the movable member 16a, 16b which is in its second connection position, are "trapped" because of the isolation of the inlet opening 10 with respect to the outlet openings 11 and the opening of corresponding link 12a, 12b (orienting device 12b in the second plane in FIGS. 3 and 7, and orienting device 12a in the foreground in FIGS. 4 and 8). In the first embodiment, the gases are trapped in a part of FIG. the corresponding orientation cavity 17a, 17b, while in the second embodiment, they are trapped before being entered. On the contrary, those having penetrated in the orientation device 14b, 14a whose movable member 16b, 16a is in its first connection position, pass through the corresponding connection opening 12b, 12a (due to the connection between the inlet opening 10 and this connecting opening 12b, 12a - orientation device 12a in the foreground in FIGS. 3 and 7, and orienting device 12b in the second plane in FIGS. 4 and 8), circulate in the cooler 1 passing from one gas flow end 8b, 8a to the other 8a, 8b, then pass through the connecting opening 12a, 12b of the orientation device 14a, 14b whose movable member 16a, 16b is in its second connection position, and finally exit through the outlet opening 11 (due to the position of the movable member 16a, 16b in its second connection position).

Thus, by switching the connection positions of the two movable members 16a, 16b, the flow direction of the gas in the pipe bundle 3 is reversed. This system of orientation of the gases 2 thus makes it possible to introduce into the cooler 1 the gases recirculated by one or other of the longitudinal ends 9a, 9b of each gas circulation pipe 3. Thus, by permuting regularly the connection positions of the two movable members 16a, 16b, the coldest portion of each pipe 3 (which is most prone to fouling due to a deposit of unburned hydrocarbon lacquer and soot) is alternated, which thus distributes the deposits at the two longitudinal ends 9a, 9b and limits the risk of obstruction due to a large accumulation. Moreover, this regular permutation in the case where the recirculating gases are particularly hot makes it possible to introduce, by one or other of the longitudinal ends 9a, 9b, gases whose temperature allows the dissociation of lacquers (approximately 250 ^° C.) or soot ( about 35O ⁰ C).

In addition, the orientation cavity 17a, 17b of each orientation device 14a, 14b is delimited by the space that can be occupied by the corresponding movable member 16a, 16b during its displacement. In the present embodiments, each movable member 16a, 16b is rotatably mounted about an axis of rotation 18a, 18b with respect to which the corresponding orientation cavity 17a, 17b has a symmetry. Here, the two axes of rotation 18a, 18b (and therefore the axes of symmetry) are parallel (more precisely, the two movable members 16a, 16b have the same axis of rotation 18a, 18b.

More specifically, in the present embodiment, each fixed structure 15a, 15b comprises an inlet cavity 19a, 19b which is specific thereto and which connects the corresponding orientation cavity 17a, 17b to the common opening 10, an outlet cavity 20a, 20b which is specific to it and which connects the corresponding orientation cavity 17a, 17b to the common outlet opening 11, and a connecting cavity 21a, 21b which is its own and which connects the corresponding orientation cavity 17a, 17b to the corresponding connecting opening 12a, 12b.

As can be seen in Figure 2, in the first embodiment, each movable member 16a, 16b is formed by a flap 41a, 41b which extends in a plane passing through the corresponding axis of rotation 18a, 18b. Here, each flap 41a, 41b has a rectangular shape of which one first side 22 perpendicular to the corresponding axis of rotation 18a, 18b, has the same length as the diameter of the corresponding orientation cavity 17a, 17b and a second side 23 perpendicular to the first 22 has the same length as the thickness of the orientation cavity 17a, 17b which is thus cylindrical.

As can be seen in Figure 6, in the second embodiment, each movable member 16a, 16b is formed by a flap 42a, 42b which extends along a main plane 43a, 43b parallel to a central plane 44a, 44b passing through the corresponding axis of rotation 18a, 18b. Here, each flap 42a, 42b has, in the main plane 43a, 43b, a rectangular shape. A first side 45 of this rectangle of each flap 42a, 42b, perpendicular to the corresponding axis of rotation 18a, 18b, forms a cord on a circle having a diameter identical to that of the corresponding orientation cavity 17a, 17b. A second side 46 perpendicular to the first 45 has the same length as the thickness of the orientation cavity 17a, 17b which is thus cylindrical.

In addition, in the present embodiments the fixed structures 15a, 15b of the two orientation devices 14a, 14b are identical, and they are adjacent to each other. More specifically, the two orientation cavities 17a, 17b are separated from each other by an insulating partition of orientation 24, the two input cavities 19a, 19b are separated from each other by an insulating input partition 25 which extends the insulating partition of orientation 24, the two outlet cavities 20a, 20b are separated from each other by an insulating exit partition 26 which extends the partitions 24 and input insulators 25, and the two connecting cavities 21a, 21b are separated from each other by an insulating connecting partition 27 which the insulating partition 24, input 25 and 26. Here, the various insulating partitions 24,25,26,27 extend perpendicular to the axis of rotation 18a, 18b of the movable members 16a, 16b.

Furthermore, in the present embodiments, the two movable members 16a, 16b are secured to one another by a common shaft 28 which extends along their common axis of rotation 18a, 18b, and the two flaps 16a. , 16b are angularly offset from each other so as to be able to perform the connection position switching. In addition, in the second embodiment, the two movable members 16a, 16b are secured by a disc 48 which is perpendicular to the shaft 28 and which has the same dimensions as the cross section of the orientation cavities 17a, 17b. As a result, the first sides 25 form a rope on this disc. In addition, each flap 42a, 42b is completed by a cylindrical surface 50 extending over the arc corresponding to the rope formed by the first side 45.

In the present embodiments, each orientation cavity 17a, 17b is arranged in the following manner: the orifice 29a, 29b opening towards the inlet opening 10 (the orifice 29a, 29b ensuring the connection with the cavity 19a, 19b) is located opposite the orifice 30a, 30b opening towards the outlet opening 10 (the orifice 30a, 3b ensuring the connection with the outlet cavity 20a, 20b) and at 90 ° of the orifice 31a, 31b opening towards the connection opening 12a, 12b corresponding (the orifice 31a, 31b ensuring the connection with the connecting cavity 21a, 21b).

In the first embodiment, the offset angle between the two flaps 41a, 41b is (near) 90 °. In the second embodiment, the offset angle between the two flaps 42a, 42b is close to 180 ° and the angular sector defined by the rope formed by the first sides 45 is 90 °, therefore, the length of the first sides 45 is equal to the product of the length of the diameter of the disk 48 by half of the square root of 2.

Furthermore, in the present embodiments, the inversion system also makes it possible to short-circuit the chiller 1 when each mobile member 16a, 16b is in an intermediate position halfway.

In the first embodiment, each mobile member 16a, 16b can take two intermediate positions halfway: a direct short-circuit position in which one of the second sides 23 of the flap 41a, 41b is opposite (at the center) of the orifice 29a, 29b opening towards the inlet opening 10 (the other second side 23 lying opposite (in the center) of the orifice 30a, 30b opening towards the outlet opening 11) ( movable member 14a in the foreground of Figure 5), and an indirect short-circuit position in which one of the second sides 23 of the flap 41a, 41b is opposite (in the center) of the orifice 31a, 31b opening to the connecting opening 12a, 12b corresponding (movable member 14b in the second plane of Figure 5). When the movable member 16a, 16b of one of the two orientation devices 14a, 14b is in its position of direct short circuit, the movable member 16b, 16a of the other orientation device 14b, 14a is in its position of indirect short circuit.

In intermediate position halfway, on the one hand, the portion of gas flowing in the orientation device 14a, 14b whose movable member is in its direct short-circuit position flows on each side of the flap 41a, 41b and passes directly from the inlet cavity 19a, 19b to the outlet cavity 20a, 20b (majority portion of the gas), and, secondly, the complementary portion of the gas flowing in the other orientation device 14b , 14a is oriented towards the corresponding connecting opening 12b, 12a, bypasses the flap 16b, 16a (via the connecting cavity 21b, 21a) and exits through the outlet cavity 20b, 20a.

In the second embodiment, each movable member 16a, 16b can take two intermediate positions halfway: one in which the second sides 46 of the flap 42a, 42b occupy (entirely) the orifice 31a, 31b opening towards the corresponding orientation opening 12a, 12b (movable member 16b in the second plane of Figure 9), the other in which the second sides 46 of the flap 42a, 42b in a position (entirely) diametrically opposite the orifice 31a, 31b opening to the corresponding orientation opening 12a, 12b (movable member 16a in the foreground of Figure 9). When the movable member 16a, 16b of one of the two orientation devices 14a, 14b is in a direct short-circuit position, the movable member 16b, 16a of the other orientation device 14b, 14a is in the other short-circuit position. In an intermediate position halfway, the gases flowing in the orientation devices 14a, 14b pass directly from the inlet cavity 19a, 19b to the outlet cavity 20a, 20b, no flap 42a, 42b impeding their flow.

Thus, the half-way intermediate position makes it possible to short-circuit the cooler 1 and not to cool the recirculating gases before they are introduced into the engine, which is particularly advantageous during cold engine operation, in particular when it starts.

The mode of actuation of the movable members 16a, 16b can be binary, between the two connection positions and the two intermediate positions halfway. In the first embodiment, each of these positions is angularly offset by 45 °, and in the second embodiment, this offset is 90 °. This mode of operation makes it possible, when the engine is cold and the temperature of the circulating gases to be maximum, to short-circuit the cooler 1 and, when the engine is sufficiently hot, to cool the gases in recirculation. by circulating them in the cooler 1, in one direction or the other.

The actuation mode can also be proportional, each movable member 16a, 16b can then take any position between the two connection positions. In such an actuation mode, the proportion of recirculating gas bypassing the cooler 1 depends on the position of the two movable members 16a, 16b: plus the proportion of gas that can pass directly from the inlet cavity 19a, 19b to the outlet cavity 20a, 20b without passing through the cavity of link 21a, 21b is important (the more the movable members 16a, 16b are close to their intermediate position at the respective halfway), the greater the proportion of gas bypassed the chiller 1 is important. The inversion system 13 thus makes it possible to regulate, in this mode of operation, the temperature of the gases recirculated before they are introduced into the engine.

The present invention is not limited to the embodiment described in connection with the figures.

It would be possible to have fixed structures having different shapes from each other, and / or not being adjacent to each other. In addition, one (or both fixed structures) may or may not have an inlet cavity, an outlet cavity, and / or a connecting cavity (the orifices of the orientation cavities opening towards the inlet openings , output and link then opening directly to these openings). In addition, in the case of two adjacent fixed structures, they could be separated from each other by other than simple partitions. Furthermore, in the case where the fixed structures have at least one additional cavity (inlet, outlet, connection) to the orientation cavity, in the case, in particular of a separation of these cavities by a partition, the separations could not not be in the extension of each other (the separation being however continuous), for example the different partitions could have different orientations. It would also be possible for the two movable members to be physically distinct from one another while being functionally correctly arranged. In the case of two movable members fixed relative to each other, as in the embodiment presented above, it is possible that the insulating partition orientation (disc-shaped) is carried by the common tree to both moving parts

(completely or partially with in this case the rest of the insulating partition - in the form of crown - carried by the fixed structure).

It would also be possible, in order to increase the variation of the proportion of gas bypassing the cooler for the positions of the movable members close to the connection positions, to add to the second sides of each flap shutters which would extend peripherally and which would be shaped so as to gradually discover the various orifices opening towards the inlet, outlet and connection openings. Such shutters could also be arranged at one or other of these orifices. The shape of these shutters could be triangular arched.

Claims

A gas steering system (2) comprising an inlet opening (10), an outlet opening (11), two connecting openings (12a, 12b) adapted to be connected to one another by an auxiliary device (1), and an inversion system (13) for circulating the gas from the inlet opening (10), before being discharged through the outlet opening (11), into the device annex (1) in one direction or the other, characterized in that the inversion system (13) is formed by two orientation devices (14a, 14b) which are isolated from each other, each comprising, on the one hand, a fixed structure (15a, 15b) of its own and which has an orientation cavity (17a, 17b) opening to the common inlet (10) and outlet (11) and a connection opening (12a, 12b) of its own, and, on the other hand, a movable member (16a, 16b) of its own, which is arranged in the corresponding orientation cavity (17a, 17b), and Q ui is movable between a first connection position in which it communicates the corresponding connection opening (12a, 12b) with the inlet opening (10) and isolates it from the outlet opening (11), and a second connection position in which it communicates the corresponding connection opening (12a, 12b) with the outlet opening (11) and isolates it from the inlet opening (10), the two orientation (14a, 14b) being arranged relative to each other so that when the movable member (16a, 16b) of one of the devices (14a, 14b) is in one of the two connection positions , that (16b, 16a) of the other device (14b, 14a) is in the other of these two positions.

2. Gas steering system (2) according to claim 1, characterized in that the orientation cavity (17a, 17b) of each orientation device (14a, 14b) is delimited by the space that can be occupied by the movable member (16a, 16b) corresponding during its displacement.

3. Gas steering system (2) according to claim 2, characterized in that the movable member

(16a, 16b) of each orientation device (14a, 14b) is rotatably mounted about an axis of rotation (18a, 18b) with respect to which the corresponding orientation cavity (17a, 17b) is symmetrical.

4. Gas steering system (2) according to claim 3, characterized in that the two movable members (16a, 16b) are secured to one another by a common shaft (28) extending according to their axis of rotation (18a, 18b) identical.

5. Gas steering system (2) according to claim 4, characterized in that each movable member (16a, 16b) is formed by a flap (41a, 41b) rectangular, each connecting cavity (17a, 17b) having the shape of a cylinder whose diameter corresponds to the length of a first side (22) of the shutter (41a, 41b) perpendicular to the corresponding axis of rotation (18a, 18b), and whose thickness corresponds to the length of a second side (23) perpendicular to the first (22).

The gas steering system (2) according to claim 5 dependent on claim 4, characterized in that the two flaps (16a, 16b) are angularly offset from each other by an angle of about 90 °.

7. Gas steering system (2) according to claim 4, characterized in that each movable member (16a, 16b) is formed by a flap (42a, 42b) which extends along a main plane (43a, 43b). ) parallel to a central plane (44a, 44b) passing through the axis of rotation (18a, 18b), each connecting cavity (17a, 17b) having the shape of a cylinder whose diameter corresponds to a root of 2 times the length of a first side (22) of the flap (42a, 42b) perpendicular to the axis of rotation (18a, 18b), the thickness of which corresponds to the length of a second side (23) perpendicular to the first (23) 22).

8. Gas steering system (2) according to claim 7 dependent on claim 4, characterized in that the two flaps (16a, 16b) are angularly offset from each other by an angle of about 180 °.

9. Gas steering system (2) according to one of claims 1 to 8, characterized in that the fixed structures (15a, 15b) of the two orientation devices (14a, 14b) are identical and adjacent to each other. one to another.

10. A gas guidance system (2) according to claim 9, characterized in that the two orientation cavities (17a, 17b) are separated from each other by an orientation isolating partition (24) .

11. Gas steering system (2) according to claim 10 dependent on one of claims 3 to 8, characterized in that the insulating partition orientation (24) extends perpendicularly to the axis of rotation (18a, 18b) of the movable members (16a, 16b).

12. Gas steering system (2) according to claim 11 dependent on one of claims 4 to 8, characterized in that the insulating partition orientation (24) is carried by the shaft (28) common to two movable members (16a, 16b).

13. Gas steering system (2) according to one of claims 1 to 12, characterized in that each orientation device (14a, 14b) comprises an inlet cavity (19a, 19b), a cavity of an outlet (20a, 20b) and a connecting cavity (21a, 21b) which are specific thereto and which connect the orientation cavity (17a, 17b) to, respectively, the common inlet opening (10), common outlet opening (11) and the corresponding connecting opening (12a, 12b).

14. Gas steering system (2) according to claim 13 dependent on one of claims 10 to 12, characterized in that the two inlet cavities (19a, 19b), the two outlet cavities (20a, 20b), and the two connecting cavities (21a, 21b) are separated from each other by respectively an inlet insulating partition (25), an insulating exit partition (26) and an insulating connecting partition. (27).

15. Gas steering system (2) according to claim 14 dependent on one of claims 10 to 12, characterized in that the inlet (25), outlet (26), and connection isolating walls extend (27) the orientation isolating partition (24).