JP5327307B2 - Exhaust gas recirculation device for internal combustion engine - Google Patents

Description

  The present invention relates to an exhaust gas recirculation device for an internal combustion engine that extracts exhaust gas from an exhaust passage of the internal combustion engine and guides the exhaust gas to an intake passage.

  As an exhaust gas recirculation device for an internal combustion engine, a part of the exhaust gas is taken out as an EGR gas from an exhaust passage downstream of a turbine of a turbocharger and introduced into an intake passage upstream of a compressor, and an exhaust gas is exhausted from an exhaust passage upstream of the turbine. A high-pressure exhaust gas recirculation passage that takes out a part as EGR gas and introduces it into an intake passage downstream of the compressor is known depending on the operating state of the internal combustion engine (Patent Document 1). In addition, Patent Documents 2 and 3 exist as prior art documents related to the present invention.

JP-A-2005-76456 Japanese Patent No. 2607175 JP 2003-269260 A

  When using the low pressure exhaust gas recirculation passage, the EGR gas is guided upstream of the compressor of the turbocharger, so that carbon fine particles contained in the EGR gas and foreign matters such as water vapor, water droplets and freezing generated due to the cooling of the EGR gas, etc. Flows into the compressor. The turbocharger compressor includes an impeller that rotates about an axis that passes through the center of the intake passage, and the impeller faces the intake passage. For this reason, foreign matter may collide with the impeller and promote damage or wear of the impeller.

  Therefore, an object of the present invention is to provide an exhaust gas recirculation device for an internal combustion engine that can suppress damage and wear of a compressor impeller due to collision of foreign matter contained in EGR gas.

The exhaust gas recirculation device of the present invention is applied to an internal combustion engine equipped with a turbocharger having a compressor provided in an intake passage and a turbine provided in the exhaust passage and driving the compressor, and exhaust gas is exhausted from the exhaust passage. In an exhaust gas recirculation apparatus for an internal combustion engine having an exhaust gas recirculation passage that extracts a part as EGR gas and leads it into the intake air passage upstream of the compressor, the concentration of EGR gas in the central portion of the intake air passage A concentration distribution forming means for forming an EGR gas concentration distribution higher than the EGR gas concentration at the end of the compressor upstream of the compressor, and the exhaust gas recirculation passage and the intake passage join as the concentration distribution forming means Air that does not contain EGR gas can be guided to the intake passage downstream from the junction and upstream from the compressor. That the air passage is provided, wherein the air passage, by having an air introduction part that can guide air into the intake passage is opened from the outer periphery to the inner periphery of the intake passage, The problem described above is solved (claim 1).

  According to this exhaust gas recirculation apparatus, the concentration distribution forming means converts the EGR gas concentration distribution at the central portion in the transverse direction of the intake passage to a concentration distribution of EGR gas higher than the EGR gas concentration at the end portion in the transverse direction. It can be formed upstream. Therefore, even if the EGR gas contains foreign matters such as carbon fine particles, water vapor, water droplets, and icing, most of the foreign matters collide with the rotation center portion where the impeller provided in the compressor has a relatively low circumferential speed. Thereby, since the collision of the foreign material to the outer peripheral portion where the circumferential speed of the impeller is relatively high can be avoided, the impeller can be prevented from being damaged or worn by the collision of the foreign material contained in the EGR gas.

Further , according to the exhaust gas recirculation device of the present invention, air that does not contain EGR gas is introduced into the intake passage by the air passage, so that the air is introduced to the radially outer side in the intake passage, that is, at the end in the transverse direction of the intake passage. Can be unevenly distributed. As a result, the EGR gas guided to the intake passage via the merging portion is guided to the central portion of the intake passage. Therefore, it is possible to form an EGR gas concentration distribution upstream of the compressor in which the concentration of EGR gas in the central portion in the transverse direction of the intake passage is higher than the concentration of EGR gas in the end portion in the transverse direction.

In one aspect of the present invention, the air introduction section, the circumferential swirling flow swirling in the direction of the intake passage may have a swirl flow generating means for giving to the air leading to the intake passage (according Item 2 ). In this case, since the swirl flow is given to the air introduced by the air introduction part, it is easy to make the air given the swirl flow unevenly distributed at the end in the transverse direction of the intake passage.

In one aspect of the present invention, the apparatus may further include a flow rate limiting unit that is provided upstream of the merging portion and that limits a flow rate of air flowing into the intake passage separately from air introduced through the air passage. ( Claim 3 ) In this case, the flow rate of the air introduced from the outer periphery of the intake passage by the air passage can be relatively increased by restricting the air flow rate by the flow restriction means.

  As described above, according to the present invention, the EGR gas is introduced into the intake passage from the introduction portion, whereby the EGR gas is guided to the rotation center portion of the compressor impeller. For this reason, even if the EGR gas contains foreign matters such as carbon fine particles, water vapor, water droplets, and icing, most of the foreign matters collide with the center of rotation of the impeller where the circumferential speed is relatively low. It is possible to avoid collision of a foreign object with the outer peripheral portion having a relatively high value. Thereby, the damage and wear of the impeller due to the collision of the foreign matter contained in the EGR gas can be suppressed.

The figure which showed the internal combustion engine in which the exhaust gas recirculation apparatus which concerns on the 1st reference example with respect to embodiment of this invention was integrated. The enlarged view to which the introduction part shown by FIG. 1 and its periphery were expanded. The cross-sectional schematic diagram along the III-III line of FIG. The enlarged view which expanded the introduction part and its periphery which concern on the 2nd reference example with respect to embodiment of this invention . The cross-sectional schematic diagram along the VV line | wire of FIG. The enlarged view which expanded the introduction part and its periphery which concern on the 3rd reference example with respect to embodiment of this invention . FIG. 7 is a schematic sectional view taken along line VII-VII in FIG. 6. The enlarged view which expanded the introduction part and its periphery which concern on the 4th reference example with respect to embodiment of this invention . FIG. 9 is a schematic cross-sectional view taken along line IX-IX in FIG. 8. The figure which showed the internal combustion engine in which the exhaust gas recirculation apparatus which concerns on the 1st form of this invention was integrated. The enlarged view to which the air introduction part of FIG. 10 and its periphery were expanded. FIG. 12 is a schematic sectional view taken along line XII-XII in FIG. 11. The enlarged view which expanded the air introduction part which concerns on the 2nd form of this invention, and its periphery. FIG. 14 is a schematic sectional view taken along line XIV-XIV in FIG. 13.

( First reference example )
10 to 14 show an embodiment of the present invention, and FIGS. 1 to 9 show a reference example having a common part with the embodiment of the present invention. First, reference examples shown in FIGS. 1 to 9 will be described. FIG. 1 shows an internal combustion engine in which an exhaust gas recirculation apparatus according to a first reference example for the embodiment of the present invention is incorporated. The internal combustion engine 1 is mounted on a vehicle as a driving power source, and is configured as an in-line four-cylinder type diesel engine in which four cylinders 2 are arranged in one direction. Each cylinder 2 is provided with a fuel injection valve 3 so that its tip faces the cylinder 2, and these fuel injection valves 3 are connected to a common rail 4 that holds the fuel at a predetermined fuel pressure. Yes. An intake passage 6 and an exhaust passage 7 are connected to each cylinder 2. The intake passage 6 includes an intake manifold 8 branched for each cylinder 2, and the exhaust passage 7 includes an exhaust manifold 9 that collects exhaust discharged from each cylinder 2. The internal combustion engine 1 fills each cylinder 2 with air filtered through the intake duct 10 via the intake manifold 8 and self-ignites the fuel injected into each cylinder 2 by the fuel injection valve 3 in the compression stroke. Let Exhaust gas discharged from each cylinder 2 is collected by an exhaust manifold 9, and the collected exhaust gas is discharged into the atmosphere after harmful substances are purified by an exhaust gas purification device 11.

  The internal combustion engine 1 is equipped with a turbocharger 12 that supercharges air using exhaust energy. The turbocharger 12 includes a compressor 13 provided in the intake passage 6 and a turbine 14 provided in the exhaust passage 7, and is a known one that drives the compressor 13 by the turbine 14 that has obtained exhaust energy. The compressor 13 includes an impeller 15, and the impeller 15 is accommodated in a compressor housing 16. The turbine 14 includes a turbine blade 17, and the turbine blade 17 is accommodated in a turbine housing 18. These housings 16 and 18 are connected to a center housing 19, and a bearing 19 a that rotatably supports a rotating shaft 20 that connects the impeller 15 and the turbine blade 17 so as to rotate together is mounted on the center housing 19. ing. The rotary shaft 20 is supported so as to be rotatable about an axis Ax1 extending so as to penetrate the central portion 6a in the transverse direction of the intake passage 6. Therefore, the impeller 15 and the turbine blade 17 can rotate about the axis Ax1, respectively. The compressor housing 16 is part of the intake passage 6 and includes an opening 16a that opens in the direction of the axis Ax1. The turbine housing 18 forms a part of the exhaust passage 7 and includes an opening 18a.

  An intake air cooling intercooler 21 is provided in the intake passage 6 on the downstream side of the compressor 13. Further, the exhaust passage 7 is provided with a supercharging pressure adjusting device 22 that adjusts the supercharging pressure within an allowable limit. The supercharging pressure adjusting device 22 bypasses the turbine 14 and sends exhaust gas downstream of the turbine 14. A bypass passage 23 for guiding and a waste gate valve 24 for opening and closing the bypass passage 23 are provided.

  The internal combustion engine 1 is provided with an exhaust gas recirculation device 25 that suppresses an increase in the combustion temperature in the cylinder 2 by recirculating exhaust gas to the intake system. The exhaust gas recirculation device 25 takes out part of the exhaust gas from the exhaust passage 7 as EGR gas and introduces it into the intake air passage 6 upstream of the compressor 13, a cooling device 27 that cools the EGR gas, and the exhaust gas recirculation passage. And an exhaust gas recirculation valve 28 for adjusting the flow rate of the EGR gas flowing through the exhaust gas 26. The amount of EGR gas introduced into the intake passage 6 (EGR amount) is set according to the operating state of the internal combustion engine 1, and the EGR amount is adjusted from the opening of the exhaust gas recirculation valve 28 and the EGR gas introduction position. This is also implemented by operating the throttle valve 29 provided in the upstream intake passage 6 in association with the opening.

  The exhaust gas recirculation passage 26 is provided with an introduction portion 30 disposed in the intake passage 6. 2 is an enlarged view of the introduction portion 30 and its periphery, and FIG. 3 is a schematic cross-sectional view taken along the line III-III of FIG. As shown in these drawings, the introduction portion 30 includes a tubular member 31 extending in the longitudinal direction of the intake passage 6 and a connection passage portion 32 connected to the tubular member 31. The tubular member 31 is disposed in the central portion 6a in a state surrounded by the inner wall 6b of the intake passage 6 and opens toward the upstream side and the downstream opening portion 31a that opens toward the downstream side of the intake passage 6. And an upstream opening 31b. The opening areas of these openings 31a and 31b are set to the same area. The tubular member 31 constitutes an inner passage portion according to the present invention. The connection passage portion 32 is opened on the inner peripheral surface of the tubular member 31, whereby the connection passage portion 32 can guide the EGR gas to the tubular member 31 as indicated by a broken arrow in FIG.

  As is apparent from FIGS. 2 and 3, the EGR gas is introduced into the intake passage 6 from the tubular member 31, whereby the EGR gas is guided to the rotation center portion of the impeller 15 of the compressor 13. That is, due to the introduction of EGR gas from the tubular member 31, the EGR gas concentration distribution in which the concentration of EGR gas at the center in the transverse direction of the intake passage 6 is higher than the concentration of EGR gas at the end in the transverse direction is Formed upstream. Therefore, even if the EGR gas contains foreign matters such as carbon fine particles, water vapor, water droplets and freezing, the foreign matters collide with the rotation center portion of the impeller 15 having a relatively low circumferential speed. Thereby, since the collision of the foreign material to the outer peripheral portion having a relatively high circumferential speed is avoided, damage and wear of the impeller 15 due to the collision of the foreign material can be suppressed. The distance between the downstream opening 31a and the impeller 15 is set within a range in which the above-described concentration distribution is maintained. This is because if the distance is excessive, the intended effect is reduced because the EGR gas diffuses.

  Since the tubular member 31 also has the upstream opening 31b, air flows into the tubular member 31 and flows out from the downstream opening 31a together with the EGR gas. That is, since air guided to the intake passage 6 can pass through the tubular member 31, an increase in air resistance due to the arrangement of the tubular member 31 can be suppressed.

  The passage cross-sectional area of the connection passage portion 32 is set to be smaller than the opening area of the downstream side opening portion 31 a of the tubular member 31. Therefore, the flow rate difference between the flow rate of the gas flowing out from the downstream opening 31a and the flow rate of the gas flowing outside the tubular member 31 can be suppressed. Thereby, mixing with the gas which flows out out of the downstream opening part 31a, and the gas which flows the outer side of the tubular member 31 can be suppressed. Further, since the EGR gas passes through the tubular member 31, it is possible to suppress the EGR gas from spreading in the transverse direction of the intake passage 6. Thereby, EGR gas can be effectively concentrated on the rotation center part of the impeller 15.

( Second reference example )
Next, a second reference example for the embodiment of the present invention will be described with reference to FIGS. This reference example has the same configuration as the first reference example except for the configuration of the introduction part. Hereinafter, the characteristic part of the second reference example will be described, and the description of the common part with the first reference example will be omitted.

FIG. 4 is an enlarged view of the introduction portion 40 and its periphery according to the second reference example , and FIG. 5 is a schematic cross-sectional view taken along the line VV of FIG. As shown in these drawings, the introduction portion 40 according to the second reference example is disposed in the central portion 6a of the intake passage 6 and connected to the inner passage portion 41 and an inner passage portion 41 extending in the longitudinal direction thereof. A connecting passage 42. The inner passage portion 41 extends in the transverse direction and the longitudinal direction of the intake passage 6 and is connected to the inner wall 6 b of the intake passage 6, and the intake passage sandwiched between the partition wall portions 43. 6 inner walls 6b. The pair of partition wall portions 43 are arranged in parallel with each other at a predetermined interval. The inner passage 41 has a downstream opening 41a that opens toward the downstream side of the intake passage 6 and an upstream opening 41b that opens toward the upstream side thereof. The opening areas of these openings 41a and 41b are set to the same area. The connection passage portion 42 opens to the inner side of the inner passage portion 41, so that the connection passage portion 42 can guide EGR gas to the inner passage portion 41 as indicated by a broken line arrow in FIG. 4. The passage cross-sectional area of the connection passage portion 41 is set to be smaller than the opening area of the downstream side opening portion 41 a of the inner passage portion 41. According to this reference example , the EGR gas is introduced into the intake passage 6 from the inner passage portion 41, whereby the EGR gas is guided to the rotation center portion of the impeller 15 of the compressor 13. Thereby, an effect substantially equivalent to the effect of the 1st reference example mentioned above is exhibited.

( Third reference example )
Next, a third reference example for the embodiment of the present invention will be described with reference to FIGS. This reference example has the same configuration as the first reference example except for the configuration of the introduction part. Hereinafter, the characteristic part of the third reference example will be described, and the description of the common part with the first reference example will be omitted.

FIG. 6 is an enlarged view of the introduction part 50 and its periphery according to the third reference example , and FIG. 7 is a schematic cross-sectional view taken along the line VII-VII of FIG. As shown in these drawings, the introduction portion 50 according to the third reference example is disposed in the central portion 6a of the intake passage 6 and extends in the longitudinal direction thereof, and also opens downstream toward the downstream side of the intake passage 6. An opening 50a is provided. Although not shown, the introduction portion 50 may be bent to the outside in the transverse direction on the upstream side of the intake passage 6 and connected to the exhaust gas recirculation passage 26. Further, when the intake passage 6 is bent at the upstream side thereof, the introduction portion 50 may extend straight and be connected to the exhaust gas recirculation passage 26 at the bent portion of the intake passage 6.

According to the third reference example , the EGR gas is introduced into the intake passage 6 from the inner passage portion 41, whereby the EGR gas is guided to the rotation center portion of the impeller 15 of the compressor 13. Thereby, breakage and wear of the impeller 15 due to the collision of the foreign matter contained in the EGR gas can be suppressed.

( Fourth reference example )
Next, a fourth reference example for the embodiment of the present invention will be described with reference to FIGS. This reference example corresponds to a modification of the third reference example . Therefore, the description of the common part with the third reference example is omitted. FIG. 8 is an enlarged view of the introduction part 50 and its periphery according to the fourth reference example , and FIG. 9 is a schematic cross-sectional view taken along the line IX-IX in FIG. As shown in these drawings, the fourth reference example includes an enclosing passage portion 51 surrounding the introduction portion 50. The surrounding passage portion 51 is disposed in the intake passage 6 and opens toward the upstream side and the downstream side of the intake passage 6. The downstream opening 51 a is located on the downstream side of the opening 50 a of the introduction part 50. As shown in FIG. 9, the surrounding passage portion 51 is disposed substantially coaxially with the introduction portion 50 and is configured in a cylindrical shape.

According to the fourth reference example , an effect equivalent to that of the third reference example can be achieved, and the EGR gas flowing out from the introduction portion 50 by the surrounding passage portion 51 is suppressed from spreading in the transverse direction of the intake passage 6. Therefore, the EGR gas can be effectively concentrated on the center of rotation of the impeller 15.

( First form )
Next, a first embodiment of the present invention will be described with reference to FIGS. In the following description, components common to the above-described reference examples are denoted by the same reference numerals in the drawings, and description thereof is omitted. The first mode is characterized in that air containing no EGR gas is introduced from the outer peripheral side of the intake passage in order to form the above-described EGR gas concentration distribution upstream of the compressor. FIG. 10 shows an internal combustion engine in which the exhaust gas recirculation apparatus according to the first embodiment is incorporated. The internal combustion engine 1 of FIG. 10 is provided with an air passage 61 for introducing air into the intake passage 6 downstream of the junction 60 between the exhaust recirculation passage 26 and the intake passage 6 and upstream of the compressor 13. . One end of the air passage 61 is connected upstream of the throttle valve 29, and an air introduction portion 62 is provided at the other end.

  FIG. 11 is an enlarged view of the air introduction part 62 and its periphery, and FIG. 12 is a schematic cross-sectional view taken along line XII-XII in FIG. As shown in these drawings, the air introduction portion 62 opens from the outer peripheral side of the intake passage 6 to the inner peripheral side and guides air into the intake passage 6. And four air introduction ports 63 that penetrate therethrough and an air introduction chamber 64 that surrounds the outer peripheral surface of the intake passage 6 so as to cover the introduction port 63 and communicates with the air passage 62.

As shown in FIG. 10, the internal combustion engine 1 can limit the flow rate of air flowing into the intake passage 6 separately from the air introduced through the air passage 61 by restricting the intake passage 6 with the throttle valve 29. By restricting the flow rate of the air, the flow rate of the air introduced in the air passage 61 is relatively increased. Thus, throttling valve 29 functions as a flow restricting means according to the present invention. The operating method of the throttle valve 29 can be set as appropriate. For example, the throttle valve 29 can be operated so that the opening degree is reduced as the gas amount of EGR gas increases.

According to the first embodiment , air that does not include EGR gas is introduced into the intake passage 6 by the air passage 61, so that the air is radially outside in the intake passage 6, that is, at the transverse end of the intake passage 6. Can be unevenly distributed. As a result, the EGR gas guided to the intake passage 6 via the junction 50 is guided to the central portion 6 a of the intake passage 6. Therefore, an EGR gas concentration distribution in which the concentration of EGR gas in the central portion 6 a in the transverse direction of the intake passage 6 is higher than the concentration of EGR gas in the end portion in the transverse direction can be formed upstream of the compressor 13.

( Second form )
Next, a second embodiment of the present invention will be described with reference to FIGS. This form corresponds to a modification of the first form . Therefore, the description of the common part with the first embodiment is omitted.

FIG. 13 is an enlarged view of the air introduction portion and its periphery according to the second embodiment , and FIG. 14 is a schematic cross-sectional view taken along line XIV-XIV in FIG. As shown in these drawings, the air passage 71 of this embodiment has an air introduction portion 72. Although not shown, one end of the air passage 71 is connected to the upstream side of the throttle valve 29 as in the first embodiment . As in the first embodiment , the air introduction portion 72 includes four air introduction ports 73 that penetrate from the outer peripheral side to the inner peripheral side of the intake passage 6 and the intake passage 6 so as to cover the introduction port 73. An air introduction chamber 74 that surrounds the outer peripheral surface and communicates with the air passage 61 is provided. Further, the air introduction portion 72 further includes a flap 75 as a swirl flow generating means for imparting a swirl flow F swirling in the circumferential direction of the intake passage 6 to the air guided into the intake passage 6. In this embodiment, a total of four flaps 75 are provided for each air inlet 73. Each flap 75 is configured to extend in the substantially same direction as the tangential direction of the inner peripheral surface of the intake passage 6. As a result, the flow direction of the air from the air introduction chamber 74 to the intake passage 6 via the air introduction port 73 is aligned with the tangential direction by the flap 75, so that the swirl flow F swirling in the circumferential direction of the intake passage 6 is generated. It is formed in the intake passage 6.

According to the second embodiment , in addition to being able to exhibit the same effect as the first embodiment , the swirling flow F is given to the air guided into the intake passage 6, so that the air to which the swirling flow is given is It becomes easy to make it unevenly distributed to the end of the intake passage 6 in the transverse direction. In other words, the centrifugal force of the swirling flow F makes it difficult for the air to diffuse toward the central portion 6a of the intake passage 6 and to stay at the end.

In each embodiment described above, the air communication passage of the first and second embodiment to function as a density distribution formation means in accordance with the present invention. However, this invention is not limited to each form mentioned above, It can implement with a various form. In the first and second embodiments, the exhaust gas recirculation passage 26 may be provided with the introduction portions 30, 40, and 50 of each of the reference examples described above, but as shown in FIGS. 26 may be simply connected to the intake passage 6. When the introduction portions 30, 40, 50 of the reference examples described above are provided in the exhaust gas recirculation passage 26, the EGR gas is concentrated in the central portion 6 a of the intake passage 6 in these introduction portions. Since the air can be unevenly distributed to the end portion, it becomes possible to make the concentration distribution of the EGR gas in the intake passage 6 more prominent. In this case, the combination of any one of the introduction parts 30, 40, 50 and any one of the air passages 61, 71 constitutes the concentration distribution forming means according to the present invention.

In the first and second embodiments, one end of the air passage is connected to the intake passage to take out the air, but the present invention is achieved by connecting one end of the air passage to an air supply source that is different from the intake passage. May be implemented. In this case, air can be pumped to the outer periphery of the intake passage using pressurizing means such as an air pump.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 6 Intake passage 6a Center part 6b Inner wall 7 Exhaust passage 12 Turbocharger 13 Compressor 14 Turbine 15 Impeller 26 Exhaust recirculation passage 29 Throttle valve (flow restriction means)
30 Introduction part (concentration distribution forming means)
31 Tubular member (inner passage)
31a downstream opening 31b upstream opening 32 connection passage part 40 introduction part 41 inner passage part 41a downstream opening part 41b upstream opening part 42 connection passage part 43 partition wall part 50 introduction part 50a downstream opening part 51 enclosure passage Part 60 Junction part 61 Air passage (concentration distribution forming means)
62 Air introduction part 71 Air passage (concentration distribution forming means)
Ax1 axis F swirl flow

Claims (3)

The present invention is applied to an internal combustion engine equipped with a turbocharger having a compressor provided in an intake passage and a turbine provided in an exhaust passage and driving the compressor, and a part of exhaust gas is taken out from the exhaust passage as EGR gas. In an exhaust gas recirculation device for an internal combustion engine, comprising an exhaust gas recirculation passage leading into the intake passage upstream of the compressor,
Concentration distribution forming means for forming an EGR gas concentration distribution upstream of the compressor, wherein the concentration of EGR gas in the central portion of the intake passage is higher than the concentration of EGR gas at the end in the transverse direction ;
As the concentration distribution forming means, there is an air passage that can guide air that does not contain EGR gas to the intake passage that is downstream of the merging portion where the exhaust gas recirculation passage and the intake passage join and upstream of the compressor. Provided,
The exhaust gas recirculation apparatus for an internal combustion engine, wherein the air passage has an air introduction portion that opens from an outer peripheral side to an inner peripheral side of the intake passage and can guide air into the intake passage . The air introduction portion of claim 1, characterized in that it has a swirling flow generating means for giving to the air directing a swirling flow swirling in the circumferential direction of the intake passage in the intake passage An exhaust gas recirculation device for an internal combustion engine. Provided upstream from the merging portion, claim 1 or 2, characterized in that the air introduced in the air passage, further comprising a separate flow restriction means for restricting the flow rate of air flowing into the intake passage 2. An exhaust gas recirculation device for an internal combustion engine according to 1.

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