JP6201737B2 - Drainage device for internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine of a vehicle, and more particularly to a drainage device that drains moisture from intake and exhaust.

As an exhaust gas purification method for a diesel engine, a method using a NOx trap catalyst is known. The NOx trap catalyst captures NOx in exhaust gas in an oxidizing atmosphere, releases the trapped NOx in a reducing atmosphere, and reduces it to N ₂ or the like, thereby reducing the NOx emission concentration. In addition, a diesel engine-equipped vehicle is provided with a filter device that removes particulate matter (PM) in the exhaust. The NOx trap catalyst is generally downstream of the filter device from the viewpoint of heat resistance and arrangement space. Arranged on the side.

  Furthermore, an exhaust gas recirculation (EGR) system is known in which part of the exhaust gas is returned to the intake side to lower the combustion temperature of the combustion chamber and reduce NOx in the exhaust gas. The EGR system includes a high-pressure EGR system for returning exhaust gas from the turbine upstream exhaust passage of the turbocharger to the compressor downstream intake passage, and an oxidation catalyst and filter device downstream exhaust passage downstream from the turbine to the compressor upstream intake passage. There is a low pressure EGR system that returns exhaust gas. Here, in an internal combustion engine provided with cooling means such as a low-pressure EGR device and an intercooler, condensation is generated when the intake air including exhaust gas passes through the cooling means and is cooled. If this condensed water is sent together with the intake air from the intake passage to the combustion chamber, there is a risk of causing a water hammer.

  An example of an exhaust emission control device for an internal combustion engine that solves the above-described problem is disclosed in “Patent Document 1”. In this exhaust purification device, a storage tank that stores condensed water generated by the intercooler, a heating device that heats the condensed water to form steam, and a water vapor supply path that is connected to the storage tank and an exhaust passage on the upstream side of the catalyst And the condensed water is converted into water vapor and supplied to the upstream exhaust passage of the catalyst.

JP 2013-180757 A

In the above-described technology, it is prevented that condensed water is sent to the combustion chamber and causes water hammer. However, a heating device that heats the condensed water to form steam is necessary, and the installation of this device increases costs and space. Problems such as securing are likely to occur. Therefore, it is conceivable to adopt a configuration in which a condensed water discharge passage is installed in order to discharge the condensed water generated in the intercooler to the upstream exhaust pipe of the NOx trap catalyst.
In this case, when condensed water discharged from the outlet of the condensed water discharge passage flows to the NOx trap catalyst arranged downstream thereof, and the catalyst is rapidly cooled by the condensed water, carrier cracking is likely to occur due to thermal stress, There is a problem that exhaust gas deteriorates.

  Furthermore, since sufficient boost pressure cannot be obtained in the low load region of the engine, the condensate flows backward to the intake passage when the condensate discharge passage is opened and cannot be discharged to the exhaust passage. Is likely to occur. Therefore, it is desired to adopt a configuration that increases the pressure difference between the inlet and outlet of the condensed water discharge passage so that the condensed water can always be discharged.

  An object of the present invention is to solve the above-mentioned problems. The object of the present invention is to adopt a configuration in which the condensed water discharged from the condensed water discharge passage does not rapidly cool the NOx trap catalyst, and always discharge the condensed water to the exhaust passage. An object of the present invention is to provide a drainage device for an internal combustion engine that can be made possible.

According to the first aspect of the present invention, an enlarged diameter portion formed on the upstream side of the exhaust aftertreatment means disposed on the exhaust passage of the internal combustion engine, and one end of the intake passage of the internal combustion engine are connected to the exhaust aftertreatment means. A drain passage for connecting the other end to the upstream side of the exhaust passage and discharging condensed water in the intake passage to the exhaust passage, and a rear end portion of the upstream exhaust pipe of the exhaust aftertreatment means It extends as an extension pipe part in the diameter expansion front part of the diameter part, and the opening at the other end of the drainage channel is upward in the gravity direction of the extension pipe part so as to face the extension pipe part in the diameter expansion front part. It is characterized by being arranged.

  According to a second aspect of the present invention, in the drainage device for an internal combustion engine according to the first aspect of the present invention, the end of the extension pipe part is formed with an extension part extending outward in the radial direction of the extension pipe part. Features.

According to a third aspect of the present invention, in the drainage device for an internal combustion engine according to the first or second aspect, the diameter expansion front portion of the container body of the exhaust aftertreatment means forms a cone-shaped inclined portion, and the drainage channel The other end is connected to the inside of the enlarged diameter front part.

The invention of claim 4, wherein, in the road drainage device for an internal combustion engine according to any one of claims 1 to 3, has a intercooler, arranged in the intake passage, one end of the drainage channel is the It is connected to the intake passage on the downstream side of the intercooler.

In the first aspect of the present invention, the condensed water condensed by the intercooler is discharged to the exhaust passage on the upstream side of the exhaust post-treatment means through the drainage passage, so that it is vaporized by the heat of the exhaust and passes through the exhaust post-treatment means to the outside of the vehicle. Can be discharged. Further, since at least a part of the opening at the other end of the drainage channel and the extension pipe part in the front part of the enlarged diameter face each other, the condensed water is diffused by hitting the extension pipe part, and the vaporization of the exhaust is promoted. At the same time, vaporization is further promoted by the heat of the extension tube. Thereby, the condensed water is vaporized or scattered to be atomized and then introduced into the exhaust aftertreatment means, so that the risk of clogging or catalyst carrier cracking can be reduced. Furthermore, the water that flows out from the other end of the drainage channel can be discharged so as to abut on the extension pipe part located on the lower side in the direction of gravity, and the water from the drainage channel can be diffused and scattered to the catalyst side. Can do.

  In the second aspect of the invention, the condensed water discharged from the other end of the drainage channel toward the extension pipe part is further returned to diffuse the liquid condensed water to the upstream side of the exhaust passage. Vaporization can be promoted by the heat of the outer peripheral wall and the inner wall portion of the front part of the enlarged diameter.

In the third aspect of the present invention, since the extension pipe part is arranged inside the cone-shaped inclined part, the condensed water flowing out from the other end of the drainage channel is caused by the heat of the outer peripheral wall of the extension pipe part and the inner wall part of the enlarged diameter part. It reliably moves to the exhaust aftertreatment means side while being heated. This further reduces the risk of clogging the exhaust aftertreatment means or cracking of the catalyst carrier.

According to the fourth aspect of the present invention, the condensed water generated downstream of the intercooler is discharged to the exhaust passage through the drainage channel, so that the engine can be prevented from causing water hammer.

1 is an overall configuration diagram of an intake / exhaust system of a vehicle-mounted diesel engine equipped with a drainage device for an internal combustion engine according to an embodiment of the present invention. The catalytic converter used with the drainage device of the internal combustion engine of Drawing 1 is shown, (a) is an expanded partial notch sectional view of the front part, and (b) is an AA line sectional view in (a). The catalytic converter used by other embodiment of this invention is shown, (a) is an expanded partial notch sectional drawing of a front part, (b) is a BB sectional drawing in (a). The catalytic converter used by the modification of other embodiment of FIG. 3 is shown, (a) is an expanded partial notch sectional drawing of a front part, (b) is CC sectional view taken on the line in (a). The catalytic converter used by other embodiment of this invention is shown, (a) is an expanded partial notch sectional drawing of a front part, (b) is the DD sectional view taken on the line in (a). The catalytic converter used by other embodiment of this invention is shown, (a) is an expanded partial notch sectional drawing of a front part, (b) is the EE sectional view taken on the line in (a). The catalytic converter used by the modification of other embodiment of FIG. 6 is shown, (a) is an expanded partial notch sectional drawing of a front part, (b) is the FF sectional view taken on the line in (a).

The features of the drainage device for an internal combustion engine to which the present invention is applied will be described with reference to the following drawings.
In short, the present invention is characterized by a drainage dispersion configuration that can prevent the catalytic device from being damaged when draining the condensed water generated in the intake passage to the upstream side of the catalytic device in the exhaust passage.
Here, the case where the drainage device for an internal combustion engine of the present invention is applied to an air supply / exhaust system of a vehicle-mounted diesel engine will be described as a first embodiment.

  A vehicle-mounted diesel engine (hereinafter referred to as an engine) 1 on which a drainage device for an internal combustion engine according to the first embodiment is mounted includes a cylinder block 2 that forms a central portion of a main body, and a cylinder head 3 is provided on the cylinder block 2. An intake pipe 4 constituting an intake passage IR is connected to the intake side of the cylinder head 3 and an exhaust pipe 5 constituting an exhaust passage ER is connected to the exhaust side. A fuel injection pump 14 is connected to the cylinder head 3 via a common rail 13. Further, the cylinder head 3 is connected to the other end of a blow-by gas passage 21 for discharging blow-by gas having one end connected to the intake pipe 4 on the downstream side of the air filter 6.

The intake pipe 4 includes an air filter 6, a low pressure throttle valve 7, a low pressure EGR valve 8, a turbocharger 9 (not shown), an intercooler 10, a high pressure throttle valve 11, a high pressure from the upstream side of the intake passage IR. An EGR valve 12 and the like are provided.
The exhaust pipe 5 is provided with a turbine (not shown) of the turbocharger 9, an oxidation catalyst 15, and a filter device 16 as an exhaust filter from the upstream side of the exhaust passage on the cylinder block 2 side.

The oxidation catalyst 15 carries a noble metal catalyst such as platinum, and has an action of converting NO in the exhaust into NO ₂ and an action of oxidizing harmful components such as HC and CO in the exhaust. Yes. NO ₂ has a stronger oxidizing action than NO, and the oxidation reaction of particulate matter (diesel particulates) captured by the filter device 16 by NO ₂ is promoted. The NO ₂ is reduced and removed by a NOx trap catalyst 18 described later. The filter device 16 is a filter device (diesel particulate filter) that captures particulate matter in exhaust gas, and the captured particulate matter is burned and removed by the strong oxidizing action of NO ₂ .

An oxygen concentration sensor (LAFS) 17 that detects the amount of oxygen concentration in the exhaust gas is provided on the downstream side of the filter device 16, and a catalytic converter 19 that incorporates a NOx trap catalyst 18 that is a catalyst on the downstream side thereof, Further, an oxygen concentration sensor 20 is provided on the downstream side. The NOx trap catalyst 18 as exhaust aftertreatment means disposed on the exhaust passage ER captures NOx in an oxidizing atmosphere, releases the trapped NOx in a reducing atmosphere containing, for example, HC, CO, and the like (N ₂ ) Is a purifying device having a function of reducing to. That is, NO ₂ generated by the oxidation catalyst 15 and NO remaining in the exhaust gas without being oxidized by the oxidation catalyst 15 are captured, reduced to nitrogen (N ₂ ), and released.

  A high pressure EGR device 22 having a high pressure EGR pipe 23 and a high pressure EGR cooler 24 is disposed below the high pressure EGR valve 12. One end of the high-pressure EGR pipe 23 is connected to the intake pipe 4 between the high-pressure throttle valve 11 and the cylinder head 3, and the other end is connected to the exhaust pipe 5 between the cylinder head 3 and the turbine of the turbocharger 9. A high-pressure EGR cooler 24 is provided in the middle. One end of the high pressure EGR pipe 23 is opened and closed by the high pressure EGR valve 12.

  Below the low pressure EGR valve 8, a low pressure EGR device 25 is disposed as an exhaust gas recirculation device having a low pressure EGR pipe 26 and a low pressure EGR cooler 27. One end of the low-pressure EGR pipe 26 is connected to the intake pipe 4 between the low-pressure throttle valve 7 and the compressor of the turbocharger 9, and the other end is connected to the exhaust pipe 5 between the filter device 16 and the NOx trap catalyst 18. A low pressure EGR cooler 27 is provided in the middle. One end of the low pressure EGR pipe 26 is opened and closed by the low pressure EGR valve 8.

Next, a drainage device M1 for an internal combustion engine according to Embodiment 1 of the present invention that causes condensed water generated in the intake passage IR to flow into the exhaust passage ER through the drainage passage wr will be described.
Here, the drain wr is connected to the intake passage IR of the intake pipe 4 between the intercooler 10 and the high-pressure throttle valve 11 at the inlet 281, which is an opening at one end thereof, on the downstream side of the intercooler. A drain port 282 which is an opening at the other end is connected to the upstream side of the exhaust passage of the NOx trap catalyst 18 which is a processing means.
The connection position of one end of the drainage channel wr is not limited to the intake pipe 4 between the intercooler 10 and the high-pressure throttle valve 11. For example, the drainage pipe that forms the drainage channel wr as shown by a two-dot chain line in FIG. A configuration may be adopted in which the inlet 281a at one end of 28a is connected to the upstream exhaust pipe 5 ′ upstream of the engine body. Thereby, the condensed water generated inside the exhaust passage EX during idling of the internal combustion engine can be discharged through the drainage passage wr.
An on-off valve 29 is disposed in the middle of the drain pipe 28, and a control means 30 is connected to the on-off valve 29 as an on-off valve control unit for performing on-off control of the on-off valve.

  As described above, the control means 30 opens the on-off valve 29 when the amount of condensed water stored in the drain pipe 28 reaches a certain amount, or when the operation time or travel distance of the engine 1 reaches a certain value. And has a function of discharging the condensed water in the drain pipe 28 through the catalytic converter 19 to the outside of the vehicle. Further, the control means 30 detects the oxygen concentration in the intake gas leaked from the drain pipe 28 and the oxygen concentration sensor 20 leaks through the drain pipe 28, and when this reaches a predetermined value on the lean side, the drain pipe 28. Therefore, it is determined that the condensed water has been completely removed from the valve, and the on-off valve 29 is closed. The control of the control means 30 prevents the intake gas from being discharged from the drain pipe after the drain of the condensed water from the drain pipe 28 is completed, thereby causing a decrease in torque and output of the engine 1.

  Next, as shown in FIG. 1, a catalytic converter 19 having a NOx trap catalyst (exhaust aftertreatment means) 18 is connected to the rear end of the upstream side exhaust pipe 501 forming the exhaust passage ER. As shown in FIG. 2A, the catalytic converter 19 includes a cylindrical container body (shell) that forms a diameter-enlarged portion of the exhaust passage ER. The container main body includes a main portion 191 that houses and holds the NOx trap catalyst 18, a diameter expansion front portion 192 that is a diameter expansion portion on the front side of the exhaust passage ER continuously formed in the main portion 191, and a diameter expansion rear portion on the rear side of the exhaust passage ER. 193.

The enlarged diameter front portion 192 forms a cone-shaped inclined portion (front cone) that gradually increases the diameter of the exhaust passage toward the downstream of the exhaust passage, and its front end is connected to the upstream exhaust pipe 501 upstream of the exhaust passage. The enlarged diameter rear portion 193 forms a cone-shaped inclined portion that gradually reduces the exhaust passage diameter toward the downstream, and the rear end thereof is connected to the downstream exhaust pipe 502 on the downstream side of the exhaust passage.
As shown in FIG. 2A, the rear end portion of the upstream side exhaust pipe 501 overlaps with the front end of the enlarged diameter front portion 192 and is welded to each other, and then extends straight to the vicinity of the central portion in the enlarged diameter front portion 192. The tube portion 5011 is extended and formed. Note that the rear end edge of the extension pipe portion 5011 is disposed toward the substantially central region of the carrier front surface f1 that supports the NOx trap catalyst 18.

As shown in FIG. 2 (a), the enlarged diameter front portion 192 that forms an inclined portion has a boss 31 welded to the top of its outer wall, and the upper end side of the through hole provided in the boss 31 is the other end of the drain pipe 28. Connected to a drain side. The lower end side of the through hole of the boss 31 penetrates the enlarged diameter front part 192 and forms a drain outlet 282 toward the inside of the enlarged diameter front part 192.
Here, as shown in FIG. 2 (b), the drainage port 282 which is the other end of the drainage channel is arranged on the upper side in the gravity direction g of the extension pipe part 5011.

The operation of such a drainage device M1 for an internal combustion engine will be described.
During operation of the engine 1, particularly when the low-pressure EGR device 25 is used, a large amount of condensed water is generated at the outlet of the intercooler 10. The generated condensed water passes through the drainage channel and is sent into the enlarged diameter front portion 192 located in the vicinity of the upstream side of the NOx trap catalyst 18 and is discharged outside the vehicle through the catalytic converter 19. In this case, when the on-off valve 29 provided in the middle of the drainage pipe 28 forming the drainage channel is closed, it is stored in the drainage pipe 28. The on-off valve 29 is used when the amount of condensed water stored by a water level sensor (not shown) provided in the drain pipe 28 reaches a certain amount, or when the operation time or travel distance of the engine 1 reaches a certain value. The control means 30 is driven to open the valve.

  The exhaust that has flowed through the exhaust passage ER during operation of the engine 1 flows into the container body (shell), and then diffuses and flows into the carrier front surface f1 that holds the NOx trap catalyst 18. At that time, as shown in FIG. 2 (a), in the inner space of the enlarged diameter front portion 192 forming the front cone, the diameter is increased toward the exhaust path downstream side (right side in the figure), and the upstream internal pressure Per is relatively small. The downstream inner pressure Per is relatively large. Here, a drain outlet 282 is opened on the front side of the enlarged diameter front portion 192, and the condensed water at the outlet of the intercooler 10 through the drain pipe 28 due to the venturi effect because the upstream internal pressure Per at the same position is relatively small due to the venturi effect. Is discharged from the drain outlet 282 into the enlarged diameter front portion 192 due to the pressure difference.

At this time, as shown in FIG. 2 (b), the condensed water flowing out from the drain port 282 is discharged so as to come into contact with the extension pipe portion 5011 located on the lower side in the gravity direction g, and is indicated by a two-dot chain line arrow. Thus, the condensed water is reliably dispersed and diffused. After that, it flows in the exhaust path direction X which is the direction of the exhaust path center line. Thereafter, the condensed water is vaporized and evaporated by the heat of the exhaust, and is scattered on the front surface f1 of the carrier that supports the NOx trap catalyst 18, passes through the catalytic converter 19, and is discharged outside the vehicle.
In this manner, since the drain outlet 282 of the drainage channel and the extension pipe part 5011 in the diameter expansion front part 192 are at least partially opposed to each other, the condensed water hitting the extension pipe part 5011 is diffused to promote vaporization. At the same time, vaporization is further promoted by the heat of the extension pipe portion 5011. Thereby, the condensed water is vaporized or scattered to be atomized and then introduced into the catalytic converter 19 (exhaust aftertreatment means), so that the risk of clogging or catalyst carrier cracking can be reduced.

In the drainage device M1 for the internal combustion engine of the first embodiment described above, the exhaust gas flows out in the exhaust passage direction X from the extension pipe portion 5011 having a straight tube shape. At this time, the exhaust gas and the atomized condensation riding on the flow are provided. The water mixture abuts on the carrier front surface f1 of the NOx trap catalyst 18 and flows as it is or diffuses in the diameter-expanding direction.
Instead of this, a drainage device M2 for an internal combustion engine according to the second embodiment having the configuration as shown in FIGS. 3A and 3B will be described.

The drainage device M2 of the internal combustion engine of the second embodiment is different from the drainage device M1 of the first embodiment only in the shape of the extension pipe portion 5011a, and the other configurations are the same. For this reason, overlapping members are denoted by the same reference numerals, description thereof is omitted, and different extension pipe portions 5011a are mainly described with reference to FIGS. 3 (a) and 3 (b).
As shown in FIG. 3 (a), a catalytic converter 19a having a NOx trap catalyst 18 is provided on the exhaust passage, and a container main body forming a diameter-expanded portion thereof has a main portion 191a and a cone-shaped front portion thereof. It has an enlarged diameter front part 192a and a rear cone-shaped enlarged diameter rear part 193a.

As shown in FIG. 3A, the upstream side exhaust pipe 501 is welded to the enlarged diameter front part 192a and then extends as an extended pipe part 5011a along the exhaust passage direction X to the vicinity of the central part of the enlarged diameter front part 192a. Formed.
The extension pipe part 5011a here has a rear end part formed as a return part 5012a with an extension part extending outward in the radial direction of the extension pipe part 5011a.

  In the case of the drainage device M2 for the internal combustion engine, the condensed water from the drainage port 282 comes into contact with the lower extension pipe portion 5011a in the gravitational direction g and is dispersed and diffused. Further, the condensed water is returned to the upstream side of the exhaust passage by the return 5012a, and the condensed water is reliably diffused. Thereafter, the condensed water is vaporized and evaporated by the heat of the exhaust, flows in the exhaust passage direction X, scatters to the NOx trap catalyst 18, passes through here, and is discharged outside the vehicle. When the return pipe 5012a is provided at the end of the exhaust pipe as described above, it becomes difficult for the condensed water droplet to ride on the exhaust gas flow (arrow indicated by a two-dot chain line), the diffusion effect is further increased, and the effect of preventing carrier cracking is increased.

In the drainage device M2 for the internal combustion engine of the second embodiment described above, the extension pipe portion 5011a forms the return portion 5012a at the rear end portion, but the outer diameter of the return portion 5012a may be further increased. This will be described below as an apparatus modification M2 ′.
In the modification M2 ′ of the drainage device for the internal combustion engine of the second embodiment, as shown in FIGS. 4A and 4B, a catalytic converter 19b having a NOx trap catalyst 18 is provided on the exhaust passage. Here, an upstream exhaust pipe 501 is welded to the enlarged diameter front part 192b of the catalytic converter 19b, and an extended pipe part 5011b is formed to extend to the vicinity of the center of the enlarged diameter front part 192b.

The extension pipe part 5011b is formed as an enlarged return part 5012b with an extension part whose rear end part greatly extends outward in the radial direction of the extension pipe part 5011b. The enlarged return portion 5012b is formed so that the outer peripheral edge thereof faces the inner wall surface f2 of the enlarged diameter front portion 192b while maintaining a predetermined annular gap tr.
In the case of the variation M2 ′ of the drainage device for the internal combustion engine of the second embodiment, the condensed water contacts the extension pipe portion 5011b in the same manner as the drainage device M2 for the internal combustion engine, is dispersed and diffused, and is vaporized by the heat of the exhaust, It evaporates and passes through the NOx trap catalyst 18 and is discharged outside the vehicle. In particular, it is assumed that the amount of condensed water discharged from the drain outlet 282 is large.

  In this case, the condensed water ejected from the drain port 282 to the lower extension pipe portion 5011b diffuses to the exhaust passage upstream side and the entire circumference of the extension pipe portion 5011b, and is further dispersed in the diameter increasing direction by the enlarged return portion 5012b. After being discharged from the annular gap tr at the outer peripheral edge, it is mixed into the exhaust gas flow. When the enlarged return 5012b is provided at the end of the exhaust pipe in this manner, even if a large amount of condensed water flows out, it becomes difficult to ride the exhaust gas flow (arrow indicated by a two-dot chain line), the diffusion effect is increased, and the carrier cracking prevention effect is achieved. Can be maintained.

In the modified example M2 ′ of the drainage device for the internal combustion engine according to the second embodiment described above, the enlarged return portion 5012b is formed at the rear end portion of the extension pipe portion 5011a. Next, a description will be given of a drainage device M3 for an internal combustion engine according to a third embodiment having a structure welded to the portion.
The drainage device M3 of the internal combustion engine of the third embodiment is different from the drainage device M2 ′ of the modified example of the second embodiment only in the coupling configuration of the extension pipe portion 5011c and the enlarged diameter front portion 192c. It is the same. For this reason, the same reference numerals are assigned to the overlapping members, the description thereof is omitted, and the different extension pipe portion 5011c and the enlarged diameter front portion 192c are mainly described with reference to FIGS. 5 (a) and 5 (b).

As shown in FIG. 5A, a catalytic converter 19c having a NOx trap catalyst 18 is disposed on the exhaust passage. Here, an upstream exhaust pipe 501 is welded to the diameter-expanded front part 192c of the catalytic converter 19c, and an extension pipe part 5011c is extended to the vicinity of the center of the diameter-expanded front part 192c.
The extension pipe part 5011c is formed as an enlarged return part 5012c with an extension part whose rear end part greatly extends outward in the radial direction of the extension pipe part 5011c. The enlarged return portion 5012c has an outer peripheral edge abutted against the inner wall surface f2 of the enlarged diameter front portion 192, and is welded in an annular shape to form a weld bead mc except for a part of the section near the lowest point in the gravity direction. Is done.

Here, a non-welded section 40c forming a predetermined gap tc is formed between the inner wall surfaces of the enlarged return portion 5012c and the enlarged diameter front portion 192c only in the vicinity of the lowest point in the gravity direction. Here, an annular space Ec is formed between the inner wall surfaces of the enlarged return portion 5012c and the enlarged diameter front portion 192c, and only in the space behind the enlarged diameter front portion 192c only through the predetermined gap tc in the non-welded section 40c near the lowest point in the gravity direction. Communicate.
In the case of the drainage device M3 for the internal combustion engine of the third embodiment, the condensed water comes into contact with the extension pipe portion 5011a and is diffused and stays in the annular space Ec. In addition, if the amount of the condensed water discharged is small, it is immediately discharged from the annular space Ec into the space behind the enlarged diameter front portion 192c through the predetermined gap tc in the non-welded section 40c near the lowest point in the direction of gravity. The condensed water from the non-welded section 40c is relatively far from the central side of the exhaust passage and is in a state where it is difficult to ride the exhaust gas flow. In this respect, the diffusion effect is increased and the carrier crack prevention effect can be reliably maintained.

On the other hand, when a large amount of condensed water is discharged from the drain outlet 282c, the discharge period is continued in a state where the condensed water stays in the annular space Ec and gradually gets into the exhaust gas flow from the space behind the enlarged diameter front portion 192c. It will be discharged. As described above, since the annular space Ec is prevented from temporarily discharging a large amount of condensed water, the diffusion effect increases with time, and the carrier cracking prevention effect can be maintained.
In the drainage device M3 for the internal combustion engine of Embodiment 3 described above, the annular space Ec is formed, and the non-welded section 40c is formed near the lowest point in the gravity direction of the weld bead mc. In contrast, a drainage device M4 for an internal combustion engine according to a fourth embodiment in which a non-welded section 40d having a predetermined gap td is formed obliquely above the weld bead md will be described next.

The drainage device M4 of the internal combustion engine of the fourth embodiment is the same as the drainage device M3 of the third embodiment except that the non-welded section 40d is formed obliquely above the weld bead md. For this reason, the same reference numerals are assigned to the overlapping members, the description thereof is omitted, and the different extension pipe part 5011d and the enlarged diameter front part 192d are mainly described with reference to FIGS. 6 (a) and 6 (b). .
As shown in FIG. 6A, a catalytic converter 19d having a NOx trap catalyst 18 is provided on the exhaust passage. The upstream exhaust pipe 501 is welded to the enlarged diameter front part 192d of the catalytic converter 19d, and an extended pipe part 5011d is formed to extend to the vicinity of the center of the enlarged diameter front part 192d.

  The extension pipe part 5011d is formed with an extension part 5012d having an extended part whose rear end part greatly extends radially outward of the extension pipe part 5011d. The outer peripheral edge of the enlarged return portion 5012d abuts against the inner wall surface f2 of the enlarged diameter front portion 192d, and is welded in a long annular shape except for a part of the vicinity of the lowest point in the gravitational direction to form a weld bead md. Is done. Here, two non-welded sections 40d are formed diagonally right and left above the weld bead md. Here, an annular space Ec is formed between the inner wall surfaces of the enlarged return portion 5012d and the enlarged diameter front portion 192d. Communicating with

  In the case of the drainage device M4 for an internal combustion engine according to the fourth embodiment, the condensed water comes into contact with the extension pipe portion 5011d and is diffused and stays in the annular space Ed. Since the annular space Ed is closed with the weld bead md on the lower side in the direction of gravity, the discharged condensed water continues to stay. In this way, the condensed water is temporarily stored, and the temperature rise and evaporation of the condensed water are promoted by the heat of the exhaust gas transmitted from the extension pipe portion 5011d and the diameter expansion front portion 192d. Thereby, even if a large amount of condensed water flows in temporarily, the discharge | emission from here can be suppressed and the support crack prevention effect increases. In addition, even if the vaporized condensed water is discharged from the non-welded section 40d obliquely left and right, it is relatively far from the center side of the exhaust passage, so that it is difficult to ride the exhaust gas flow. The carrier cracking prevention effect can be reliably maintained.

  In the drainage device M4 for the internal combustion engine of the above-described fourth embodiment, two non-welded sections 40d are formed obliquely on the left and right sides of the weld bead md. However, the non-welded sections 40d may be additionally formed. A description will now be given as a modification M4 ′ of the drainage device.

  In the modification M4 ′ of the drainage device for the internal combustion engine of the fourth embodiment, as shown in FIGS. 7A and 7B, the extension pipe portion 5011e is provided on the inner wall surface f2 of the diameter-expanded front portion 192e of the catalytic converter 19e. The outer peripheral edge portion of the enlarged return portion 5012e at the rear end is welded to provide an annular space Ee. Furthermore, non-welded sections 40e and 40ed are formed in the weld bead me formed here at three positions near the upper left side and the lowermost point in the direction of gravity. In the non-welded section 40ed in the vicinity of the lowest point, the condensed water temporarily stays in the annular space Ee, and a minute gap te that can promote the temperature rise and evaporation of the condensed water is formed therebetween.

  In the variation M4 ′ of the drainage device for the internal combustion engine of the fourth embodiment, it is generated by the heat of exhaust gas transmitted from the extension pipe portion 5011e and the enlarged diameter front portion 192e from the two non-welded sections 40e diagonally left and right. Condensed water vapor and scattered liquid are discharged, and condensed water heated by the heat of the exhaust is discharged from the non-welded section 40ed near the lowest point in the direction of gravity. Vaporized or liquid condensed water dispersed and discharged in the space behind the enlarged diameter front part 192c from the predetermined gap te of these three non-welded sections 40e, 40ed is relatively distant from the center side of the exhaust passage, It is difficult to ride the exhaust gas flow. In this respect, the diffusion effect is increased, and the carrier cracking prevention effect can be maintained.

Thus, if the outer periphery of the enlarged return portion 5012e and the enlarged diameter front portion 192e (front cone) are welded except for the lowest point in the gravity direction and some other sections, the discharged condensed water is temporarily removed. The effect of preventing cracking of the carrier is increased because the heat of the exhaust pipe and the enlarged diameter front portion 192e can be stored to prevent the water from becoming full while promoting the temperature rise and evaporation of the condensed water.
In the above description, the drainage device of the internal combustion engine is mounted on the on-board diesel engine. However, it may be mounted on a stationary diesel engine depending on the case, and may be further mounted on a gasoline engine. Almost the same effect can be obtained.

1 Internal combustion engine
4 Intake pipe 5 Exhaust pipe 501 Upstream exhaust pipe 5011a to 5011e Extension pipe part 5012a Return 5012b to 5012e Expanded return 9 Supercharger (turbocharger)
10 Intercooler 18 NOx trap catalyst (exhaust aftertreatment means)
19 Catalytic converter 191 Main part 192 Diameter expansion front part 20 Oxygen concentration sensor 25 Exhaust gas recirculation device (low pressure EGR device)
28 Drain pipe 30 Control means (open / close valve controller)
wr Drainage channel IR Intake passage ER Exhaust passage M1-M4 Internal combustion engine drainage device X Exhaust passage direction

Claims (4)

An enlarged diameter portion formed on the upstream side of the exhaust aftertreatment means disposed on the exhaust passage of the internal combustion engine;
A drainage passage that has one end connected to the intake passage of the internal combustion engine and the other end connected to the exhaust passage upstream side of the exhaust aftertreatment means, and discharges condensed water in the intake passage to the exhaust passage,
The rear end portion of the upstream exhaust pipe of the exhaust post-processing means extends as an extension pipe portion in the diameter-expanded front portion of the diameter-expanded portion,
The drainage device for an internal combustion engine, characterized in that an opening at the other end of the drainage channel is arranged on the upper side in the gravity direction of the extension pipe part so as to face the extension pipe part in the diameter-expanded front part. The end of the extension pipe part is formed with an extension part extending outward in the radial direction of the extension pipe part.
2. The drainage device for an internal combustion engine according to claim 1. The diameter expansion front part of the container main body of the exhaust aftertreatment means forms a cone-shaped inclined part,
The other end of the drainage channel was connected to the inside of the enlarged diameter front part,
The drainage device for an internal combustion engine according to claim 1 or 2, characterized in that An intercooler disposed in the intake passage,
The drainage device for an internal combustion engine according to any one of claims 1 to 3, wherein one end of the drainage channel is connected to an intake passage on the downstream side of the intercooler .

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