JP2008255853A - 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 compatibly establishing heat radiation and heat insulation of EGR gas with a simple structure. <P>SOLUTION: The exhaust gas recirculation device 10 is provided with an exhaust gas recirculation passage 12 having a double structure part 16 having an inner pipe 17 and an outer pipe 18 combined, an intermediate chamber 19 formed between an outer circumference surface of the inner pipe 17 and an inner circumference surface of the outer pipe 18, and an open close device 20 opening the intermediate chamber 19 and making outside air pass through the same when exhaust gas temperature is not less than predetermined temperature and closing the intermediate chamber 19 and retaining outside air when exhaust gas temperature is less than predetermined temperature. <P>COPYRIGHT: (C)2009,JPO&INPIT

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, an exhaust gas recirculation passage that takes out exhaust gas from an exhaust passage and introduces it into an intake air passage has a double-pipe structure, and cooling water is circulated between an inner inner tube and an outer outer tube. There is one that cools the exhaust gas taken out from the exhaust passage as EGR gas (Patent Document 1). There is also known an exhaust gas recirculation device in which an air layer for heat insulation is formed by retaining air in a closed space formed between an inner tube and an outer tube having a double-pipe structure (Patent Document 2).

JP 2004-116495 A JP 2004-176645 A

  When high-temperature exhaust gas flowing through the exhaust passage of the internal combustion engine is taken out as EGR gas, there is a risk of thermal damage due to a large temperature difference at the connection with the cooling device provided in the exhaust gas recirculation passage. For this reason, it is preferable to lower the temperature of the EGR gas flowing through the exhaust passage by radiating heat from the exhaust recirculation passage. On the other hand, if the passage leading to the cooling device is lengthened, heat dissipation is promoted, but condensed water may be generated before the EGR gas is led to the cooling device depending on the operating conditions of the internal combustion engine. Accordingly, there are a region where it is preferable to perform heat dissipation of the EGR gas and a region where it is preferable to perform heat insulation (heat insulation). Therefore, it is sufficient to perform either heat dissipation or heat insulation as in the prior art described above. It can not be said.

  Therefore, an object of the present invention is to provide an exhaust gas recirculation device for an internal combustion engine that can achieve both heat dissipation and heat insulation of EGR gas with a simple configuration.

  The exhaust gas recirculation device of the present invention has a double structure portion in which an inner pipe and an outer pipe arranged outside the inner pipe are combined, and exhaust gas is taken out as an EGR gas from an exhaust passage of the internal combustion engine. An exhaust gas recirculation passage leading to an intake passage of the engine, an intermediate chamber formed between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube, and supplied with a predetermined gas, and exhaust gas taken out from the exhaust passage The predetermined gas flow state existing in the intermediate chamber according to the exhaust temperature of the gas, the gas passing state in which the predetermined gas passes through the intermediate chamber, and the gas stop in which the predetermined gas stops in the intermediate chamber The above-described problem is solved by providing switching means for switching between states.

  According to this exhaust gas recirculation device, the state of the flow of the predetermined gas supplied into the intermediate chamber is switched between a state in which the predetermined gas passes through the intermediate chamber and a state in which the predetermined gas is stopped depending on the exhaust temperature. When the predetermined gas passes through the intermediate chamber, heat exchange is performed between the EGR gas flowing through the double structure portion and the predetermined gas, and heat dissipation is promoted. On the other hand, because the predetermined gas stays in the intermediate chamber, the predetermined gas functions as a heat insulation layer, so the temperature of the EGR gas flowing through the double structure can be maintained, and the generation of condensed water is prevented. can do.

  In one aspect of the exhaust gas recirculation apparatus of the present invention, the intermediate chamber is provided with an outside air inlet through which outside air can be introduced as the predetermined gas, and an outside air outlet through which the introduced outside air can be discharged. An opening / closing member that opens the outside air inlet when the exhaust temperature is equal to or higher than the predetermined temperature and closes the outside air inlet when the exhaust temperature is lower than the predetermined temperature; and the exhaust temperature is equal to or higher than the predetermined temperature. In this case, a discharge port opening / closing member that opens the external air discharge port and closes the external air discharge port when the exhaust temperature is lower than the predetermined temperature may be provided. According to this aspect, the outside air inlet and the outside air outlet are each opened and the outside air passes through the intermediate chamber, so that heat exchange is promoted and the temperature of the exhaust gas can be quickly lowered.

  In this aspect, the outside air introduction port may be disposed at one end in the longitudinal direction of the double structure portion, and the outside air discharge port may be disposed at the other end in the longitudinal direction of the double structure portion. ). According to this aspect, since the outside air can be uniformly passed through the intermediate chamber, the efficiency of heat exchange is improved.

  In one aspect of the exhaust gas recirculation apparatus of the present invention, the intermediate chamber has an exhaust introduction port through which exhaust gas passing through the inner pipe can be introduced as the predetermined gas, and the introduced exhaust gas is located downstream of the exhaust introduction port. An exhaust return port that can be returned to the inner pipe, and the switching means opens the exhaust inlet when the exhaust temperature is equal to or higher than a predetermined temperature, and when the exhaust temperature is lower than the predetermined temperature. An inlet opening / closing member that closes the exhaust inlet may be provided. According to this aspect, when the exhaust temperature is equal to or higher than the predetermined temperature, the exhaust introduction port is opened, so that the exhaust passing through the inner pipe passes through the intermediate chamber, and heat exchange is performed between the exhaust and the outside air. Heat dissipation. On the other hand, when the exhaust gas inlet is closed, the exhaust gas existing in the intermediate chamber functions as a heat insulating layer, so that the EGR gas flowing through the double structure can be kept warm.

  In this aspect, there is further provided a blocking mechanism that is disposed in the inner pipe on the downstream side of the exhaust introduction port and on the upstream side of the exhaust return port, and closes the inner pipe when the exhaust temperature is equal to or higher than the predetermined temperature. (Claim 5). In this case, when the inner pipe is closed by the shut-off mechanism, all of the EGR gas flowing through the double structure portion passes through the intermediate chamber, so that the heat dissipation effect is further improved.

  In one aspect of the present invention, a heat radiating member provided on the outer peripheral surface of the inner tube and protruding into the intermediate chamber may further be provided. In this case, since the contact area of the gas passing through the intermediate chamber to the inner tube side increases, the heat dissipation effect of the EGR gas is further improved.

  In one aspect of the present invention, the apparatus further includes a cooling device that is provided in the exhaust gas recirculation passage and cools the EGR gas, and the double structure portion is provided between an extraction position for taking out the EGR gas and the cooling device. (Claim 7). According to this aspect, when the exhaust gas temperature is equal to or higher than the predetermined temperature, since the EGR gas is cooled by the double structure portion and then introduced into the cooling device, the temperature difference at the connection portion of the cooling device can be effectively reduced. . Thereby, generation | occurrence | production of the heat damage in a connection part can be prevented.

  As described above, according to the present invention, the state of the flow of the predetermined gas supplied into the intermediate chamber depends on the exhaust gas temperature between the state in which the predetermined gas passes through the intermediate chamber and the state in which it stops. Can be switched. When the predetermined gas passes through the intermediate chamber, heat exchange is performed between the EGR gas flowing through the double structure portion and the predetermined gas, and heat dissipation is promoted. On the other hand, because the predetermined gas stays in the intermediate chamber, the predetermined gas functions as a heat insulation layer, so the temperature of the EGR gas flowing through the double structure can be maintained, and the generation of condensed water is prevented. can do. Thereby, it is possible to achieve both heat dissipation and heat shielding of the EGR gas with a simple configuration.

(First form)
FIG. 1 shows a main part of an internal combustion engine to which an exhaust gas recirculation apparatus according to one embodiment of the present invention is applied. The internal combustion engine 1 is configured as an in-line four-cylinder diesel engine. The internal combustion engine 1 is provided with a turbocharger 2 including a compressor 2a and a turbine 2b that rotates integrally with the compressor 2a. The intake air introduced into the intake passage 3 is pressurized by the compressor 2a of the turbocharger 2 to the internal combustion engine 1. Supercharge against. An air cleaner 4 for air filtration is provided upstream of the compressor 2a. A turbine 2b is provided in the exhaust passage 5, and an exhaust purification device 6 for purifying harmful substances in the exhaust is provided downstream of the turbine 2b. The exhaust purification device 6 includes a storage reduction type NOx catalytic converter 7 and a diesel particulate filter 8 provided on the downstream side of the catalytic converter 7. As is well known, the NOx catalytic converter 7 has a function of storing NOx in the exhaust gas and reducing and purifying the stored NOx by temporarily setting the exhaust gas to the rich side. The particulate filter 8 has a base material made of a porous material capable of capturing particulate matter (particulates) in the exhaust gas, and suppresses the particulates from being discharged into the atmosphere.

  The internal combustion engine 1 includes an exhaust gas recirculation device 10 that extracts a part of exhaust gas as EGR gas and introduces it into the intake passage in order to reduce the combustion temperature of the fuel injected by the fuel injection valve 9 and reduce the NOx generation amount. Is provided. The exhaust gas recirculation device 10 includes an exhaust gas recirculation passage 12 that connects the exhaust passage 5 and the intake air passage 3, an exhaust gas recirculation valve 13 that adjusts the amount of EGR gas introduced into the intake air passage 3, and a cooling device 14 that cools the EGR gas. And. The exhaust gas recirculation passage 12 includes a double structure portion 16 disposed between the exhaust extraction position 12 a and the connection position 12 b with the cooling device 14. The double structure portion 16 is configured by combining an inner tube 17 and an outer tube 18 disposed outside the inner tube 17. An intermediate chamber 19 is formed between the outer peripheral surface of the inner tube 17 and the inner peripheral surface of the outer tube 18, and outside air (air) as a predetermined gas is supplied to the intermediate chamber 19.

  In the intermediate chamber 19, an outside air introduction port 19 a through which outside air can be introduced and an outside air discharge port 19 b through which the introduced outside air can be discharged are provided at both ends in the longitudinal direction of the double structure portion 16. Each of the outside air introduction port 19 a and the outside air discharge port 19 b opens in the direction of the center line of the double structure portion 16. Each of the outside air inlet 19a and the outside air outlet 19b is opened and closed by an opening and closing device 20 as a switching means. The opening / closing device 20 includes an upstream opening / closing part 21 for opening / closing the outside air introduction port 19a and a downstream opening / closing part 22 for opening / closing the outside air discharge port 19b. The upstream opening / closing part 21 corresponds to the inlet opening / closing member according to the present invention, and the downstream opening / closing part 22 corresponds to the discharge opening / closing member according to the present invention. Since the upstream side opening / closing part 21 and the downstream side opening / closing part 22 have the same structure, only the upstream side opening / closing part 21 will be described below, and the description of the downstream side opening / closing part 22 will be omitted.

  FIG. 2 is an enlarged sectional view taken along line II-II in FIG. The upstream side opening / closing part 21 includes eight valve bodies 23 arranged in the circumferential direction of the outside air introduction port 19a. The valve body 23 is made of a bimetal material that is deformed at a set temperature. One end of the valve body 23 is a fixed end fixed to the outer tube 17 and the other end is a free end. 3 is a cross-sectional view taken along line III-III in FIG. When each valve body 23 is lower than the set temperature, the outside air inlet 19a is closed as shown by a solid line. On the other hand, when each valve body 23 is equal to or higher than the set temperature, it is deformed as shown by the broken line in FIG. Similarly, the downstream opening / closing part 22 closes the outside air outlet 19b when the temperature is lower than the set temperature, while opening the outside air outlet 19b when the temperature is equal to or higher than the set temperature.

  The set temperatures of the open / close sections 21 and 22 are set in accordance with the exhaust temperature of the exhaust gas taken out from the exhaust passage 5. That is, the set temperature is such that the outside air inlet 19a and the outside air outlet 19a are closed when the exhaust temperature is lower than the predetermined temperature, and the outside air inlet 19a and the outside air outlet 19b are opened when the exhaust temperature is higher than the predetermined temperature. Is set. As a result, when the exhaust temperature is lower than the predetermined temperature, each of the outside air inlet 19a and the outside air outlet 19b is closed by the opening / closing device 20, whereby the intermediate chamber 19 is sealed and the outside air is retained in the intermediate chamber 19. Gas stop state. On the other hand, when the exhaust temperature is equal to or higher than the predetermined temperature, the outside air introduction port 19a and the outside air discharge port 19b are each opened by the opening / closing device 20, thereby opening the intermediate chamber 19 and allowing the outside air to pass through the intermediate chamber 19. It becomes a passing state. Thus, since the opening / closing device 20 operates according to the exhaust temperature, the exhaust gas recirculation device 10 changes the state of the flow of the outside air existing in the intermediate chamber 19 between the gas passage state and the gas retention state according to the exhaust temperature. Can be switched.

  As shown in FIG. 3, a large number of fins 25 as heat radiating members are provided on the outer peripheral surface of the inner tube 17. The fins 25 protrude into the intermediate chamber 19 and are arranged at a predetermined interval. Thereby, a contact area with the external air which passes through the inside of the intermediate chamber 19 increases, and a cooling effect improves.

  According to this embodiment, when the exhaust gas temperature is lower than the predetermined temperature, the outside air stays in the intermediate chamber 19 and the outside air functions as a heat insulating layer, so that generation of condensed water is suppressed. Further, when the exhaust gas temperature is equal to or higher than the predetermined temperature, since the outside air passes through the intermediate chamber 19, the EGR gas is cooled when it passes through the double structure portion 16. Further, since the double structure portion 16 is provided between the take-out position 12a and the cooling device 14, the cooling device after the EGR gas is cooled in the double structure portion 16 when the exhaust temperature is equal to or higher than a predetermined temperature. 14. For this reason, the temperature difference in the connection part of the cooling device 14 can be relieved effectively, and generation | occurrence | production of the thermal damage in the connection part can be prevented.

  In this embodiment, the opening / closing device 20 opens and closes each of the outside air introduction port 19 a and the outside air discharge port 19 b using deformation according to the temperature of the valve body 23 made of a bimetal material, but instead of the valve body 23. Is provided with a valve body (not shown) capable of opening and closing each of the outside air introduction port 19a and the outside air discharge port 19b, and the valve body is driven by an actuator (not shown) that operates in accordance with the exhaust gas temperature. Each of the discharge ports 19b may be opened and closed. In this case, the combination of the valve body and the actuator corresponds to the switching means of the present invention.

(Second form)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 shows an enlarged part of the exhaust system of the internal combustion engine to which the exhaust gas recirculation apparatus according to the second embodiment is applied. The main configuration of the internal combustion engine of FIG. 4 is the same as that of the internal combustion engine 1 of FIG. The same components as those of the internal combustion engine 1 are denoted by the same reference numerals in FIG.

  As shown in FIG. 4, the exhaust gas recirculation device 30 according to the second embodiment includes an exhaust gas recirculation passage 31 that extracts exhaust gas from the exhaust passage 5 as EGR gas. The exhaust gas recirculation passage 31 includes a double structure portion 32 disposed between the exhaust extraction position 31 a and the connection position 31 b with the cooling device 14. The double structure portion 32 is configured by combining an inner tube 33 and an outer tube 34 disposed outside the inner tube 33. An intermediate chamber 35 is formed between the outer peripheral surface of the inner tube 33 and the inner peripheral surface of the outer tube 34. Both ends in the longitudinal direction of the intermediate chamber 35 are closed. As will be described in detail later, the intermediate chamber 35 is supplied with exhaust gas as a predetermined gas.

  FIG. 5 shows a cross section taken along line V-V in FIG. As shown in FIG. 5, the intermediate chamber 35 is divided into two chambers 37 and 38 by a partition wall 36 extending along the center line. As shown in FIG. 4, an exhaust introduction port 35 a that communicates the inner tube 33 and the chamber 37 is provided on the side close to the take-out position 31 a. The exhaust introduction port 35a is opened and closed by an opening / closing device 39 as switching means. An exhaust return port 35b that communicates the inner tube 33 and the chamber 38 is provided downstream of the exhaust introduction port 35a. One end 36a on the downstream side of the partition wall 36 is located near the connection position 31b, and the two chambers 37 and 38 communicate with each other at the one end 36a.

  The opening / closing device 39 includes a valve body 40 having a size capable of closing the exhaust introduction port 35a and made of a bimetal material that is deformed at a set temperature. When the valve body 40 is less than the set temperature, As shown by the solid line in FIG. 4, the exhaust inlet 35a is closed. On the other hand, the valve body 40 is deformed as shown by a broken line in FIG. 4 to open the exhaust inlet 35a when the temperature is higher than the set temperature. The set temperature of the valve body 40 is set corresponding to the exhaust temperature of the exhaust gas taken out from the exhaust passage 5. That is, the set temperature is set so that the exhaust inlet 35a is closed when the exhaust temperature is lower than the predetermined temperature, and the exhaust inlet 35a is opened when the exhaust temperature is equal to or higher than the predetermined temperature. The valve body 40 corresponds to the inlet opening / closing member according to the present invention.

  The inner pipe 33 downstream of the exhaust introduction port 35a and upstream of the exhaust return port 35b is provided with a valve device 41 as a blocking mechanism for opening and closing the inner pipe 33. The valve device 41 includes a valve body 42 and a drive unit 43 that drives the valve body 42. The drive unit 43 has an opening position shown in FIG. 4 and the valve body 42 rotates approximately 90 degrees from the opening position. Then, the valve body 42 is driven between the closed position where the inner pipe 33 is closed. The operation of the drive unit 43 is controlled by an engine control unit (ECU) 45 that is a computer that appropriately controls the operating state of the internal combustion engine. The ECU 45 acquires the exhaust temperature of the exhaust gas extracted from the exhaust passage 5 based on the output signal of the exhaust temperature sensor 46 provided in the exhaust passage 5, and the valve body 42 is opened when the exhaust temperature is lower than a predetermined temperature. In the position, when the temperature is equal to or higher than the predetermined temperature, the driving unit 43 is operated so that the valve bodies 42 are respectively held at the blocking positions.

  With the above configuration, when the exhaust temperature is lower than the predetermined temperature, the exhaust introduction port 35a is closed by the opening / closing device 39 and the inner pipe 33 is opened by the valve device 41. The exhaust gas passes through the inner pipe 33 of the double structure portion 32 and is guided to the cooling device 14 as indicated by the solid line arrow in FIG. In this case, since the exhaust introduction port 35a is closed, the gas is stopped in the intermediate chamber 35 where the exhaust is stopped.

  On the other hand, when the exhaust gas temperature is equal to or higher than the predetermined temperature, the exhaust gas inlet 35 a is opened by the opening / closing device 39 and the inner pipe 33 is closed by the valve device 41. Therefore, the exhaust gas taken out from the exhaust passage 5 and guided to the inner tube 33 is returned to the inner tube 33 after passing through the intermediate chamber 35. That is, as indicated by the broken-line arrows in FIG. 4, the exhaust is led from the exhaust introduction port 35a to the chamber 37 of the intermediate chamber 35, folded back near the connection position 31b and led to the chamber 38, and then the exhaust return port 35b. Is returned to the inner tube 33. That is, when the exhaust gas temperature is equal to or higher than the predetermined temperature, the exhaust gas passes through the intermediate chamber 35. Since the opening / closing device 39 operates in accordance with the exhaust temperature in this way, the exhaust gas recirculation device 30 changes the state of the exhaust flow existing in the intermediate chamber 35 between the gas passage state and the gas stop state according to the exhaust temperature. Can be switched.

  According to the second embodiment, when the exhaust gas temperature is lower than the predetermined temperature, the exhaust gas stays in the intermediate chamber 35, and the exhaust gas functions as a heat insulating layer, so that the generation of condensed water is suppressed. Further, when the exhaust gas temperature is equal to or higher than a predetermined temperature, the exhaust gas passes through the intermediate chamber 35 so that heat is exchanged with the outside air for cooling. Similarly to the first embodiment, since the double structure portion 32 is provided between the take-out position 31a and the cooling device 14, the EGR in the double structure portion 32 when the exhaust gas temperature is equal to or higher than a predetermined temperature. The gas is cooled and then introduced into the cooling device 14. For this reason, the temperature difference in the connection part of the cooling device 14 can be relieved effectively, and generation | occurrence | production of the thermal damage in the connection part can be prevented.

  In this embodiment, the opening / closing device 39 opens and closes the exhaust introduction port 35a using deformation according to the temperature of the valve body 40 made of a bimetal material, but opens and closes the exhaust introduction port 35a instead of the valve body 40. An unillustrated valve body may be provided, and the exhaust inlet 35a may be opened and closed by driving the valve body by an unillustrated actuator that operates according to the exhaust temperature. In this case, the combination of the valve body and the actuator corresponds to the switching means of the present invention.

  In the second embodiment, when the exhaust gas temperature is equal to or higher than the predetermined temperature, the valve device 41 closes the inner pipe 33 so that all of the EGR gas flowing through the double structure portion 32 passes through the intermediate chamber 35. The valve device 41 may be omitted. In this case, the inner pipe 33 is not closed when the exhaust introduction port 35a is opened, but part of the EGR gas flowing through the double structure portion 32 is guided from the exhaust introduction port 35a to the intermediate chamber 35 and the inner pipe 33 is closed. Therefore, a certain amount of cooling effect can be obtained.

  The valve device 41 is switched between an open position for opening the inner pipe 33 and a closed position for closing the inner pipe 33. The valve device 41 holds the valve body 42 at an arbitrary position between the open position and the closed position. Also good. In this case, since the flow rate of the exhaust gas passing through the intermediate chamber 35 can be adjusted, the temperature of the exhaust gas taken out from the exhaust passage 5 can be controlled in detail.

  In the second embodiment, fins as heat radiating members that protrude into the intermediate chamber 35 can be provided on the outer peripheral surface of the inner tube 33 as in the first embodiment.

The figure which showed the principal part of the internal combustion engine to which the exhaust gas recirculation apparatus which concerns on one form of this invention is applied. The expanded sectional view along the II-II line of FIG. Sectional drawing along the III-III line of FIG. The figure which expanded and showed a part of exhaust system of the internal combustion engine to which the exhaust gas recirculation apparatus which concerns on a 2nd form is applied. Sectional drawing along the VV line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 3 Intake passage 5 Exhaust passage 10 Exhaust gas recirculation device 12 Exhaust gas recirculation passage 14 Cooling device 16 Duplex structure part 17 Inner pipe 18 Outer pipe 19 Intermediate chamber 19a Outside air introduction port 19b Outside air discharge port 20 Opening and closing device (switching means)
21 Upstream opening / closing part (inlet opening / closing member)
22 Downstream opening / closing part (exhaust port opening / closing member)
25 Fin (Heat Dissipation Member)
30 Exhaust gas recirculation device 31 Exhaust gas recirculation passage 32 Duplex structure 33 Inner pipe 34 Outer pipe 35 Intermediate chamber 35a Exhaust inlet 35b Exhaust return port 39 Opening / closing device (switching means)
40 Valve body (inlet opening / closing member)
41 Valve device (shut-off mechanism)

Claims (7)

  Exhaust gas recirculation having a double structure portion in which an inner pipe and an outer pipe arranged outside the inner pipe are combined, and exhaust gas is taken out from the exhaust passage of the internal combustion engine as EGR gas and led to the intake passage of the internal combustion engine According to the exhaust temperature of the exhaust gas taken out from the passage, the intermediate chamber formed between the outer peripheral surface of the inner pipe and the inner peripheral surface of the outer pipe and supplied with a predetermined gas, Switching means for switching a state of a flow of the predetermined gas existing in the intermediate chamber between a gas passage state in which the predetermined gas passes through the intermediate chamber and a gas stop state in which the predetermined gas stops in the intermediate chamber. And an exhaust gas recirculation device for an internal combustion engine. The intermediate chamber is provided with an outside air inlet through which outside air can be introduced as the predetermined gas, and an outside air outlet through which the introduced outside air can be discharged,
The switching means includes an inlet opening / closing member that opens the outside air inlet when the exhaust temperature is equal to or higher than a predetermined temperature, and closes the outside air inlet when the exhaust temperature is lower than the predetermined temperature; The exhaust opening / closing member that opens the outside air outlet when the temperature is equal to or higher than the predetermined temperature and closes the outside air outlet when the exhaust temperature is lower than the predetermined temperature. An exhaust gas recirculation device for an internal combustion engine.   The said outside air inlet is arrange | positioned at the one end of the longitudinal direction of the said double structure part, and the said outside air discharge port is each arrange | positioned at the other end of the longitudinal direction of the said double structure part, respectively. An exhaust gas recirculation device for an internal combustion engine. The intermediate chamber has an exhaust introduction port through which exhaust gas passing through the inner pipe can be introduced as the predetermined gas, and an exhaust return port through which the introduced exhaust gas can be returned to the inner pipe downstream from the exhaust introduction port. And
The switching means includes an inlet opening / closing member that opens the exhaust inlet when the exhaust temperature is equal to or higher than a predetermined temperature and closes the exhaust inlet when the exhaust temperature is lower than the predetermined temperature. The exhaust gas recirculation device for an internal combustion engine according to claim 1.   A shut-off mechanism that is disposed in the inner pipe downstream of the exhaust inlet and upstream of the exhaust return opening and closes the inner pipe when the exhaust temperature is equal to or higher than the predetermined temperature; The exhaust gas recirculation device for an internal combustion engine according to claim 4.   The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 5, further comprising a heat radiating member provided on an outer peripheral surface of the inner pipe and protruding into the intermediate chamber. A cooling device provided in the exhaust gas recirculation passage for cooling the EGR gas;
The exhaust gas recirculation device for an internal combustion engine according to any one of claims 1 to 5, wherein the double structure portion is provided between an extraction position for extracting EGR gas and the cooling device.

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