JP2009041551A - Exhaust gas recirculation device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas recirculation device for an internal combustion engine capable of quickly discharging condensate formed in an intake air passage out of an intake system. <P>SOLUTION: In the exhaust gas recirculation device 20 for the internal combustion engine 1 provided with a low pressure EGR passage 22 introducing part of exhaust gas to the intake air passage 4 from an exhaust gas passage 4 as EGR gas, the intake air passage 4 is provided with a double tube part 41 in which an outer tube 44 forming a part of the intake air passage 4 and an inner tube 45 arranged inside of the outer tube 44 with keeping a gap which is to be a cylindrical passage 46 are combined. The low pressure EGR passage 22 is connected to the double tube part 41 so as to introduce EGR gas into the cylindrical passage 46 from a tangential direction of the outer tube 44, a groove part 48 is provided at an inner surface 9d of a compressor 9c connected to a downstream side of the double tube part 41 in such a manner that an inner surface thereof continues to the outer tube 44, and the groove part 48 is connected to a tank 32 storing condensate via a condensate passage 49. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exhaust gas recirculation device for an internal combustion engine that includes an EGR passage that guides a part of exhaust gas from an exhaust passage to an intake passage as EGR gas.

  There is known an EGR device in which a direction changing portion is provided in an EGR passage, and a trap that opens toward the upstream side to collect condensed water generated by cooling is provided in the direction changing portion (see Patent Document 1). . In addition, Patent Documents 2 to 6 exist as prior art documents related to the present invention.

JP 2003-097361 A Japanese Patent Laid-Open No. 2002-130058 Japanese Patent Laying-Open No. 2005-076456 JP 2002-188525 A Special table 2006-500515 gazette Japanese Patent No. 2607175

  An apparatus that separates and collects liquid from gas using inertia cannot separate and collect moisture mixed in the gas as water vapor, and it is difficult to collect water droplets having a small diameter. Therefore, moisture is guided to the intake passage together with the EGR gas. Since the air sucked from outside air (hereinafter sometimes referred to as fresh air) has a lower temperature than EGR gas, moisture introduced into the intake passage and water droplets with a small diameter are cooled by fresh air and condensed water is generated. To do. The condensed water is acidified by components such as nitrogen oxide (NOx) and sulfur oxide (SOx) in the EGR gas. Therefore, there is a possibility that corrosion of equipment provided in the intake passage such as a compressor of a turbocharger and an intake pipe may proceed due to the condensed water. Further, when a plurality of direction changing portions are provided in the EGR passage so as to provide a plurality of traps as in the apparatus of Patent Document 1, the pressure loss in the EGR passage is increased by the direction changing portions. As is well known, EGR gas is introduced from the exhaust passage into the intake passage by utilizing the difference between the pressure in the exhaust passage and the pressure in the intake passage. Therefore, when the pressure loss in the EGR passage increases, the amount of EGR gas required for improving exhaust emission is increased. There is a possibility that the EGR gas cannot be sufficiently introduced into the intake passage.

  Therefore, an object of the present invention is to provide an exhaust gas recirculation device for an internal combustion engine that can quickly discharge condensed water generated in an intake passage to the outside of the intake system.

  An exhaust gas recirculation device for an internal combustion engine according to the present invention is an exhaust gas recirculation device for an internal combustion engine that includes an EGR passage that guides a part of exhaust gas from the exhaust passage to the intake passage as EGR gas. A double pipe part in which an outer pipe that forms a portion and an inner pipe that is disposed through a gap serving as a cylindrical passage is provided inside the outer pipe, and the EGR passage is provided in the cylindrical passage. It is connected to the double pipe portion so that EGR gas is introduced from the tangential direction of the outer pipe, and is connected to the downstream side of the double pipe portion so that the outer pipe and the inner surface are continuous. A groove portion is provided on the inner surface of the passage forming member forming the portion, and the groove portion is connected to a storage means for storing condensed water via the condensed water passage, thereby solving the above-described problem. ).

  According to the exhaust gas recirculation apparatus of the present invention, since EGR gas is introduced from the tangential direction into the cylindrical passage provided between the outer tube and the inner tube, the exhaust gas recirculation device is rotated downstream along the inner surface of the outer tube. A swirling flow that flows into the cylindrical passage can be formed in the cylindrical passage. Since the EGR gas introduced into the double pipe part swirls in the cylindrical passage along with the swirling flow, the condensed water generated from the EGR gas can be attached to the inner surface of the outer pipe by centrifugal force. Condensed water adhering to the inner surface of the outer tube moves along the inner surface by the flow of intake air, is guided to the passage forming member, and is collected in the groove. Thereafter, the condensed water is discharged from the groove portion to the storage means through the condensed water passage. In this way, even if condensed water is generated in the intake passage, it can be collected in the groove portion, so that the condensed water can be prevented from moving downstream from the passage forming member. Further, the condensed water can be quickly discharged out of the intake system. Therefore, corrosion of the equipment provided in the intake passage and the intake pipe forming the intake passage can be suppressed. Further, in the exhaust gas recirculation device of the present invention, since the double pipe portion is provided in the intake passage, an increase in pressure loss in the EGR passage can be prevented. Therefore, the amount of EGR gas necessary for improving exhaust emission can be sufficiently introduced into the intake passage due to the difference between the pressure in the intake passage and the pressure in the exhaust passage.

  In one form of the exhaust gas recirculation device of the present invention, the groove portion is provided over the entire circumference in the circumferential direction of the inner surface of the passage forming member, and the groove portion extends over the entire circumference in the circumferential direction of the inner surface of the passage forming member. (Claim 2). By providing the groove portion in this manner, the condensed water that has moved to the inner surface of the passage forming member can be collected more reliably.

  In one form of the exhaust gas recirculation device of the present invention, a lid portion for closing the upstream end portion may be provided at the upstream end portion of the cylindrical passage. In this case, since the inflow of intake air into the cylindrical passage can be suppressed, a stronger swirling flow can be formed in the cylindrical passage. Therefore, the adhesion of condensed water to the inner surface of the outer tube can be promoted.

  In one form of the exhaust gas recirculation device of the present invention, the lid portion may extend toward the inner surface of the outer pipe while gradually expanding from the inner pipe toward the upstream side of the intake flow. In this case, the fresh air can be quickly guided into the inner pipe without disturbing the flow of the fresh air by the lid.

  In one form of the exhaust gas recirculation device of the present invention, the internal combustion engine includes a turbocharger, the passage forming member is a compressor housing of the turbocharger, and the double pipe portion is an intake air of the compressor housing. It may be connected to the suction inlet (claim 5). Since the intake air is compressed in the turbocharger compressor and the pressure of the intake air rises, by providing a groove in the compressor housing, the condensed water is quickly discharged from the groove to the condensed water passage using the intake air pressure. Can be discharged.

  In this embodiment, the groove portion may be formed on an inner surface of the compressor housing facing an inducer portion of a compressor wheel disposed in the compressor housing. By providing the groove in such a place, the condensed water can be quickly discharged to the condensed water passage by using the pressure of the compressed intake air without allowing the condensed water to enter the compressor.

  The EGR passage may connect a section of the exhaust passage downstream of the turbocharger turbine and the double pipe portion. Since the pressure in the exhaust passage downstream from the turbine is lower than the pressure in the exhaust passage upstream from the turbine, the pressure difference between both ends of the EGR passage becomes small. In the exhaust gas recirculation apparatus of the present invention, an increase in the pressure loss of the EGR passage can be prevented, so that even if the pressure difference between both ends of the EGR passage is small as described above, the amount of EGR gas necessary for improving exhaust emission is sufficiently sucked. It can be introduced into the passage.

  In one form of the exhaust gas recirculation device of the present invention, the EGR passage is subjected to gas-liquid separation action on the gas introduced therein, and the obtained liquid is discharged from the liquid discharge pipe to the storage means, and the remaining gas The gas-liquid separation means for discharging the gas from the gas discharge pipe to the double pipe section may be provided, and the condensed water passage may connect the groove section and the gas-liquid separation means. In this case, the intake air discharged together with the condensed water from the groove portion can be returned to the intake passage through the gas-liquid separation means. Further, since the condensed water is separated from the intake air returned to the intake passage by the gas-liquid separation means, it is possible to suppress the condensed water from returning to the intake passage again. Further, when the passage forming member is a turbocharger compressor, a part of the intake air is circulated, thereby improving the surge limit of the compressor.

  As described above, according to the exhaust gas recirculation apparatus of the present invention, condensed water is attached to the inner surface of the outer pipe by centrifugal force using the swirl flow formed in the cylindrical passage of the double pipe portion, and the condensation is performed. Water can be collected in the groove and discharged out of the intake system. Therefore, the condensed water generated in the intake passage can be quickly discharged out of the intake system.

  FIG. 1 shows an example of an internal combustion engine in which an exhaust gas recirculation apparatus according to an embodiment of the present invention is incorporated. An internal combustion engine (hereinafter sometimes referred to as an engine) 1 in FIG. 1 is a diesel engine mounted as a driving power source in a vehicle, and an engine body 3 provided with a plurality (four in FIG. 1) of cylinders 2. And an intake passage 4 and an exhaust passage 5 connected to each cylinder 2. In the intake passage 4, an air cleaner 6 for filtering the intake air, a first throttle valve 7 and a second throttle valve 8 for adjusting the intake air amount, a compressor 9a of the turbocharger 9, and an intercooler for cooling the intake air 10 is provided. As shown in FIG. 1, the first throttle valve 7 is provided in a section between the air cleaner 6 and the compressor 9a, and the second throttle valve 8 may be abbreviated as an intercooler 10 and an intake manifold (hereinafter referred to as an intake manifold). ) Provided in the section between 4a. The exhaust passage 5 is provided with a turbine 9b of the turbocharger 9 and an exhaust purification device 11 for purifying exhaust.

  The engine 1 also includes an exhaust gas recirculation device 20 that introduces part of the exhaust gas from the exhaust passage 5 to the intake passage 4 as EGR gas. The exhaust gas recirculation device 20 includes a high pressure EGR passage 21 and a low pressure EGR passage 22 that connect the exhaust passage 5 and the intake passage 4. As shown in FIG. 1, the high-pressure EGR passage 21 connects a section upstream of the turbine 9 b in the exhaust passage 5 and a section between the second throttle valve 8 and the intake manifold 4 a in the intake passage 4. The low pressure EGR passage 22 connects a section of the exhaust passage 5 downstream of the exhaust purification device 11 and a section of the intake passage 4 between the first throttle valve 7 and the compressor 9a. The high pressure EGR passage 21 is provided with a high pressure EGR valve 23 for adjusting the flow rate of EGR gas passing through the high pressure EGR passage 21. The low pressure EGR passage 22 is provided with an EGR cooler 24 for cooling the EGR gas and a low pressure EGR valve 25 for adjusting the flow rate of the EGR gas passing through the low pressure EGR passage 22.

  The exhaust gas recirculation device 20 includes a condensed water collecting mechanism 30 for collecting condensed water generated from EGR gas or the like and discharging the condensed water to the outside. The condensed water collecting mechanism 30 is provided downstream of the EGR cooler 24 of the low pressure EGR passage 22 in the EGR gas flow direction, and includes a trapper 31 that collects condensed water generated as the EGR gas is cooled, and a trapper 31. A tank 32 as a storage means for storing the collected condensed water, a connection path 33 for connecting the trapper 31 and the tank 32, a discharge path 34 for discharging the condensed water stored in the tank 32, and a compressor for the intake passage 4 And a pressure introduction path 35 that connects a section between 9 a and the intercooler 10 and the tank 32.

  The condensed water collecting mechanism 30 will be described in detail with reference to FIGS. 2 and 3. FIG. 2 is an enlarged view of the condensed water collecting mechanism 30, and FIG. 3 is a view showing a cross section of the condensed water collecting mechanism 30 taken along the line III-III in FIG. As shown in FIG. 2, the trapper 31 includes a double pipe portion 41 connected to an intake air intake port of the compressor 9 a, a casing 42 provided so as to protrude from the double pipe portion 41, and a casing 42. And a guide pipe 43 serving as a gas discharge pipe disposed inside. Since the double pipe portion 41 is thus connected, the compressor housing 9c corresponds to the passage forming member of the present invention. The double pipe portion 41 includes an outer pipe 44 that forms a part of the intake passage 4, an inner pipe 45 that is provided inside the outer pipe 44 via a gap that becomes a cylindrical passage 46, and the outer pipe 44 and the inner pipe 45. And a lid portion 47 that closes the inlet on the upstream side of the intake air flow of the cylindrical passage 46 formed therebetween. The lid portion 47 is provided so as to extend toward the inner surface of the outer tube 44 while gradually expanding from the inner tube 45 toward the upstream side of the intake flow. By forming the lid portion 47 in this manner, the disturbance of the flow of fresh air flowing into the double pipe portion 41 can be suppressed.

  The casing 42 includes a cylindrical portion 42a disposed so as to surround the guide tube 43, and a funnel-shaped recovery portion 42b continuous below the cylindrical portion 42a. As shown in FIG. 3, the cylindrical portion 42a is provided with an introduction pipe 42c connected so that EGR gas is introduced into the cylindrical portion 42a from the tangential direction of the cylindrical portion 42a. The low pressure EGR passage 22 is connected to the introduction pipe 42c. In addition, a discharge pipe 42 d as a liquid discharge pipe is provided at the lower part of the recovery unit 42 b, and the discharge pipe 42 d is connected to the tank 32 through the connection path 33. The guide tube 43 has a hollow cylindrical shape. As shown in FIG. 3, the guide tube 43 passes through the guide tube 43 and is introduced into the intake passage 4 so that the gas flows into the cylindrical passage 46 from the tangential direction of the outer tube 44. It is connected to the heavy pipe portion 41. Further, a groove portion 48 is provided on the inner surface 9 d of the compressor housing 9 c of the turbocharger 9, and the groove portion 48 is connected to the cylindrical portion 42 a via a condensed water passage 49. The groove portion 48 is provided over the entire circumference in the circumferential direction of the inner surface 9d of the compressor housing 9c. Further, as shown in FIG. 2, the groove 48 is provided on the inner surface of the compressor wheel 9e disposed in the compressor housing 9c, which faces the inducer 9f. As described above, since the groove portion 48 is connected to the cylindrical portion 42a via the condensed water passage 49, if the pressure of the intake air in the groove portion 48 is too high, the intake air is exhausted to the cylindrical portion 42a, and the efficiency of the compressor 9a is increased. descend. Therefore, the position where the groove 48 is provided is appropriately set according to the pressure of each part in the compressor 9a when the intake air is compressed by the compressor 9a. As is well known, the pressure of the intake air in the inducer portion 9f increases as it proceeds downstream from the blade tip position of the compressor wheel 9e. Therefore, the groove portion 48 is set at a position where intake air is not exhausted from the compressor 9a to the cylindrical portion 42a, for example.

  A method for collecting condensed water by the condensed water collecting mechanism 30 will be described. According to the condensed water collecting mechanism 30, the EGR gas introduced into the cylindrical portion 42a via the low-pressure EGR passage 22 forms the swirl flow S1 in the cylindrical portion 42a as shown in FIG. The condensed water contained in the EGR gas can be collected by adhering to the inner surface of the cylindrical portion 42a. Thus, the casing 42 corresponds to the gas-liquid separating means of the present invention by giving a gas-liquid separating action to the gas introduced into the inside. The collected condensed water is discharged to the tank 32 through the recovery part 42b, the discharge pipe 32d, and the connection path 33. On the other hand, the remaining EGR gas is introduced into the cylindrical passage 46 from the tangential direction of the outer tube 44 through the guide tube 43. Therefore, as shown in FIG. 3, the remaining EGR gas forms a swirl flow S <b> 2 in the cylindrical passage 46. Since the remaining EGR gas also contains water as water droplets or water vapor having a small diameter, condensed water is generated when it is introduced into the intake passage 4 and cooled by fresh air, but this condensed water is generated by the swirling flow S2. Can be attached to the inner surface of the outer tube 44. Condensed water adhering to the inner surface of the outer tube 44 is guided into the compressor housing 9 c by the flow of intake air and the like, and is collected in the groove 48. Thereafter, the condensed water is discharged to the cylindrical portion 42 a through the condensed water passage 49 together with a part of the intake air by the pressure of the intake air increased by the compressor 9 a and sent to the tank 32. A part of the intake air discharged to the cylindrical portion 42 a together with the condensed water is returned again to the compressor 9 a through the guide pipe 43.

  As shown in FIG. 2, a connecting path 33 and a pressure introducing path 35 are connected to the upper part of the tank 32, and a discharge path 34 is connected to the lower part. The connection path 33 is provided with a check valve 36 that allows the flow from the trapper 31 to the tank 32 and prevents the flow from the tank 32 to the trapper 31. The pressure at which the check valve 36 starts to open, that is, the so-called cracking pressure is, for example, when the condensed water collected in the trapper 31 accumulates to an appropriate amount, and the check valve 36 is opened by its own weight. Is set as follows. The discharge path 34 is provided with a check valve 37 that allows the condensed water to be discharged from the tank 32 to the outside and prevents the backflow from the outside to the tank 32. The cracking pressure of the check valve 37 is set in a range in which the check valve 37 is not opened only by the weight of the condensed water that can be stored in the tank 32. The pressure introduction path 35 is provided with a solenoid valve 38 that opens and closes the pressure introduction path 35. Each opening / closing operation of the solenoid valve 38, the high pressure EGR valve 23, and the low pressure EGR valve 25 is controlled by a control device (not shown). As the control device, for example, an engine control unit (ECU) which is a computer for controlling the operating state of the engine 1 is used. The control device is not limited to the ECU, and a computer unit may be provided separately from the ECU, and the computer unit may be used as the control device for the exhaust gas recirculation device 20.

  Next, the operation of the exhaust gas recirculation device 20 will be described. Each opening degree of the high pressure EGR valve 23 and the low pressure EGR valve 25 is controlled such that an EGR gas having an appropriate flow rate according to the operating state of the engine 1 is introduced into the combustion chamber of the engine 1. An intake air amount and an EGR gas flow rate to be introduced into the combustion chamber of the engine 1 are set according to the operating state of the engine 1, and the first throttle valve 7 and the second throttle valve 8 are set according to the intake air amount and the EGR gas flow rate. Each opening is controlled. In addition, since these opening degree control may be a well-known control method, detailed description is abbreviate | omitted.

  The solenoid valve 38 is opened when the condensed water stored in the tank 32 is discharged, and is kept closed at other times. Condensed water can be discharged, for example, by providing a sensor for detecting the amount of condensed water stored in the tank 32, and when the detected value exceeds a predetermined value, the engine 1 is operated for a predetermined time. It may be done every time. When the solenoid valve 38 is opened, the pressure of the intake air compressed by the compressor 9a is introduced into the tank 32 through the pressure introduction path 35, and the internal pressure of the tank 32 increases. As a result of this pressure increase, the check valve 36 in the connection path 33 is closed and the check valve 37 in the discharge path 34 is opened. Therefore, the condensed water in the tank 32 is discharged through the discharge path 34. Thereafter, the solenoid valve 38 is closed when the condensed water is completely discharged from the tank 32. As a result, the internal pressure of the tank 32 gradually decreases, the check valve 37 of the discharge passage 34 is closed, and the check valve 36 of the connection passage 33 is opened, and the storage of condensed water in the tank 32 is resumed.

  According to the exhaust gas recirculation device 20 of the present invention, the condensed water is first separated from the EGR gas introduced into the intake passage 4 via the low pressure EGR passage 22 by the swirl flow S1 formed in the casing 42, and then. Condensed water is separated by the swirl flow S2 formed in the cylindrical passage 46. The condensed water separated in the cylindrical passage 46 then moves on the inner surface of the outer tube 44 and is collected in a groove portion 48 provided on the inner surface 9d of the compressor housing 9c, and is collected in the tank 32 via the condensed water passage 49. Sent. Thus, by providing the double pipe portion 41 in the intake passage 4 and introducing the EGR gas so that the swirl flow S2 is formed in the cylindrical passage 46 inside the intake passage 4, the condensed water generated in the intake passage 4 is promptly removed. It can be attached to the inner surface of the outer tube 44 and collected. Therefore, the condensed water generated in the intake passage 4 can be quickly discharged out of the intake diameter. Further, since the double pipe portion 41 is provided in the intake passage 4, it is possible to prevent an increase in useless pressure loss in the low pressure EGR passage 22. Therefore, the amount of EGR gas necessary for improving the exhaust emission of the engine 1 can be sufficiently introduced into the intake passage 4 due to the pressure difference between both ends of the low pressure EGR passage 22.

  Since the groove portion 48 is provided on the inner surface 9d of the compressor housing 9c over the entire circumference in the circumferential direction, the condensed water that has moved along the inner surface of the intake passage 4 can be reliably collected by the groove portion 48. Further, as described above, the pressure on the casing side of the inducer portion 9f increases as it proceeds downstream from the blade tip position of the compressor wheel 9e. Therefore, as shown in FIG. 2, by providing the groove portion 48 on the facing surface 9d facing the inducer portion 9f, the condensed water collected using the pressure of the compressed intake air is quickly discharged to the cylindrical portion 42a. be able to. A part of the intake air is sent from the groove portion 48 to the cylindrical portion 42a together with the condensed water, and a part of the intake air is returned to the compressor 9a again through the cylindrical portion 42a, the guide pipe 43 and the double pipe portion 41. As is well known, the surge limit of the compressor 9a can be improved by extracting a part of the intake air from the middle of the throat part where the inducer part 9f is arranged and returning it to the inlet of the throat part. Therefore, it is possible to suppress the occurrence of surging in the compressor 9a by returning a part of the intake air sent from the groove portion 48 to the cylindrical portion 42a to the compressor 9a.

  The present invention is not limited to the above-described form and can be implemented in various forms. For example, a trapper provided in an EGR passage of an engine to which the present invention is applied is not limited to a trapper that collects condensed water using centrifugal force. For example, a concave portion, a meandering portion, a baffle plate or the like may be provided in a part of the EGR passage, and condensed water may be attached to the wall surfaces to collect the condensate. Further, if the condensed water can be sufficiently collected in the double pipe portion, it is not necessary to provide a trapper in the EGR passage.

  It is not necessary to provide a lid at the upstream end of the cylindrical passage formed in the double pipe. Even if fresh air flows into the cylindrical passage from the upstream side, a swirling flow can be formed in the cylindrical passage by the EGR gas that flows in from the tangential direction, so that condensed water adheres to the inner surface of the outer tube by centrifugal force. Can do. By omitting the lid portion in this way, the manufacturing cost can be reduced and the manufacturing procedure can be simplified.

The figure which shows an example of the internal combustion engine in which the exhaust gas recirculation apparatus which concerns on one form of this invention was integrated. The figure which expands and shows a condensed water collection mechanism. The figure which shows the cross section of the condensed water collection mechanism in the III-III line of FIG.

Explanation of symbols

1 Internal combustion engine 4 Intake passage 5 Exhaust passage 9 Turbocharger 9c Compressor housing (passage forming member)
9d Inner surface of compressor housing 9e Compressor wheel 9f Inducer section 20 Exhaust gas recirculation device 22 Low pressure EGR passage (EGR passage)
32 tanks (storage means)
41 Double pipe part 42 Casing (gas-liquid separation means)
42d Discharge pipe (liquid discharge pipe)
43 Guide pipe (gas exhaust pipe)
44 Outer tube 45 Inner tube 46 Cylindrical passage 47 Lid portion 48 Groove portion 49 Condensate passage

Claims (8)

In an exhaust gas recirculation device for an internal combustion engine provided with an EGR passage that guides a part of exhaust gas as EGR gas from an exhaust passage to an intake passage,
The intake passage is provided with a double pipe portion in which an outer tube that forms a part of the intake passage and an inner tube that is disposed inside the outer tube via a gap that becomes a cylindrical passage are combined,
The EGR passage is connected to the double pipe portion so that EGR gas is introduced into the cylindrical passage from a tangential direction of the outer pipe,
A groove portion is provided on the inner surface of a passage forming member that is connected to the downstream side of the double pipe portion so as to be continuous with the outer tube and the inner surface and forms a part of the intake passage, and the groove portion passes through a condensed water passage. The exhaust gas recirculation device for an internal combustion engine is connected to a storage means for storing condensed water.   2. The exhaust gas recirculation apparatus for an internal combustion engine according to claim 1, wherein the groove portion is provided over the entire circumference in the circumferential direction of the inner surface of the passage forming member.   3. The exhaust gas recirculation device for an internal combustion engine according to claim 1, wherein a lid portion that closes the upstream end portion is provided at an upstream end portion of the cylindrical passage.   4. The exhaust gas recirculation device for an internal combustion engine according to claim 3, wherein the lid portion extends toward the inner surface of the outer pipe while gradually expanding from the inner pipe toward the upstream side of the intake flow. The internal combustion engine comprises a turbocharger;
5. The passage forming member is a compressor housing of the turbocharger, and the double pipe portion is connected to an intake air inlet of the compressor housing. An exhaust gas recirculation device for an internal combustion engine according to the item.   6. The exhaust gas recirculation device for an internal combustion engine according to claim 5, wherein the groove portion is formed on an inner surface of the compressor housing facing an inducer portion of a compressor wheel disposed in the compressor housing.   The exhaust gas recirculation of the internal combustion engine according to claim 5 or 6, wherein the EGR passage connects a section of the exhaust passage downstream from the turbine of the turbocharger and the double pipe portion. apparatus. In the EGR passage, a gas-liquid separation action is given to the gas introduced inside, the obtained liquid is discharged from the liquid discharge pipe to the storage means, and the remaining gas is discharged from the gas discharge pipe to the double pipe section. Gas-liquid separating means for discharging is provided,
The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 7, wherein the condensed water passage connects the groove portion and the gas-liquid separation means.

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