JP2019023447A - Exhaust system for engine - Google Patents

Abstract

To provide an exhaust system for an engine, capable of suppressing exhaust interference and uneven introduction of exhaust gas into an exhaust emission control device while responding to the desire of compactification.SOLUTION: To exhaust ports of #1 and #4 cylinders, #1 and #4 exhaust pipes 31, 34 are connected. The #1 and #4 exhaust pipes 31, 34 are each formed of a pipe member. #2 and #3 exhaust pipes connected to exhaust ports of #2 and #3 cylinders are each formed of a cylindrical member 41. The cylindrical member 41 has a merge cylinder part 38 and a downstream cylinder part 39. A front end 31c of the #1 exhaust pipe 31 is inserted into the Z-direction middle of the downstream cylinder part 39. In the downstream cylinder part 39 at its portion equivalent to a front end side opening 31b at the front end 31c of the #1 exhaust pipe 31, a volume portion 39d is provided. Exhaust gas from the #1 exhaust pipe 31 has a lower flow rate in the volume portion 39d. To a catalyst side opening 39a of the downstream cylinder part 39, a catalyst is connected.SELECTED DRAWING: Figure 7

Description

  The present invention relates to an engine exhaust device, and more particularly, to an exhaust pipe structure joined to an exhaust port of a multi-cylinder engine.

  An exhaust pipe is connected to each exhaust port of the engine. An exhaust purification device such as a catalyst is connected to the exhaust pipe downstream in the flow direction of the exhaust gas.

  In the prior art, for example, an exhaust pipe connected to each exhaust port of a four-cylinder engine is gathered into two pipes, and a configuration in which the exhaust pipes are gathered into one pipe on the downstream side is adopted. The exhaust emission control device is connected to the downstream end of a single pipe.

  By the way, in order to meet the demand for further downsizing of the engine of a vehicle such as an automobile and its peripheral configuration, it is considered to directly collect a plurality of exhaust pipes connected to each exhaust port into one. (Patent Documents 1 and 2).

  In Patent Documents 1 and 2, some of the exhaust pipes connected to each exhaust port are configured by a cylindrical member formed by a combination of a plurality of pressed plate members. And the exhaust apparatus which inserted the front-end | tip part of the other exhaust pipe comprised with the pipe member inward of the cylindrical member is disclosed.

Japanese Patent Laid-Open No. 03-64616 JP 2007-92669 A

  However, when further downsizing the peripheral configuration of the engine is desired, there are concerns about the problem of exhaust interference and the problem of uneven introduction of exhaust gas to the exhaust purification device. Specifically, in the techniques of Patent Documents 1 and 2, when a plurality of exhaust pipes are assembled at the same location, a problem of exhaust interference occurs.

  Further, in order to promote further downsizing of the peripheral configuration of the engine, in a case where the exhaust purification device is arranged below a portion where a plurality of exhaust pipes are arranged, a pipe connected to the exhaust purification device is not provided. It is necessary to bend. In such a case, in the pipe, the flow rate of the exhaust gas passing through the outer peripheral side of the bend is higher than the flow rate of the exhaust gas passing through the inner peripheral side. Therefore, there is a problem that the exhaust gas is unevenly introduced into the exhaust purification device, and there is a possibility that the performance of the exhaust purification device is deteriorated at an early stage.

  The present invention has been made to solve the above-described problems, and is capable of suppressing exhaust interference and uneven introduction of exhaust gas into the exhaust purification device while meeting the demand for compactness. An object is to provide an exhaust system for an engine.

  An exhaust system for an engine according to one aspect of the present invention is connected to an exhaust port of an engine in which a plurality of cylinders are arranged in series, and an exhaust purification device is connected to a downstream end in the exhaust gas flow direction. In the exhaust system, a first exhaust pipe connected to an exhaust port of one of the plurality of cylinders, and an exhaust port of at least two cylinders excluding the one cylinder among the plurality of cylinders A plurality of second exhaust pipes, wherein the first exhaust pipe is configured by a pipe member, and at least a part of the plate material is press-molded in the plurality of second exhaust pipes. Formed by a plurality of plate members, and is configured by a cylindrical member in which exhaust gas from the plurality of second exhaust pipes merges, and the exhaust purification device includes the exhaust gas in the cylindrical member At the downstream end of the gas flow direction The plurality of second exhaust pipes in the tubular member are connected to the opened openings and arranged to extend in the arrangement direction of the plurality of cylinders. Is inserted to the downstream side in the exhaust gas flow direction from the location where the exhaust gas from the merging point, and the tubular member has a portion where the opening of the tip portion of the first exhaust pipe is located, A flow rate reduction unit that reduces the flow rate of the exhaust gas from the first exhaust pipe is provided.

  The engine exhaust device according to the above aspect includes the first exhaust pipe constituted by the pipe member and the plurality of second exhaust pipes constituted by the cylindrical members, so that all the exhaust pipes are constituted by the pipe member. Therefore, the exhaust device can be made more compact as compared to the case where all the exhaust pipes are made of cylindrical members.

  Specifically, when all the exhaust pipes are to be formed by pipe members, it is difficult to make the exhaust device compact as in the above-described aspect due to manufacturing restrictions such as bending and welding of the pipe members. It is.

  In addition, when the exhaust pipe is constituted by a cylindrical member, it is difficult to form a sharp bent portion of the pipe. Therefore, when all the exhaust pipes are to be formed by the cylindrical member, the exhaust device It is difficult to reduce the size. Moreover, when it is going to comprise all the exhaust pipes with a cylindrical member, since it is necessary to ensure the width | variety of the partition part for partitioning exhaust pipes to some extent, all this exhaust pipe is also secured by this. When it is going to be constituted by a cylindrical member, it is difficult to make the exhaust device compact.

  In the engine exhaust apparatus according to the above aspect, the tip of the first exhaust pipe extends to the downstream side in the exhaust gas flow direction from the portion where the exhaust gas from the plurality of second exhaust pipes joins the cylindrical member. Since it is inserted, exhaust interference between at least the exhaust gas from the first exhaust pipe and the exhaust gases from the plurality of second exhaust pipes can be suppressed.

  Furthermore, in the exhaust system for an engine according to the above aspect, the tubular member is provided with a flow velocity reduction unit, and the flow velocity of the exhaust gas from the first exhaust pipe is reduced by the flow velocity reduction unit. The introduction of biased exhaust gas to the exhaust gas purification apparatus due to the exhaust gas from the first exhaust pipe in which the tip portion is inserted is suppressed.

  Therefore, in the engine exhaust apparatus according to the above aspect, it is possible to suppress the exhaust interference and the uneven introduction of the exhaust gas to the exhaust purification apparatus while meeting the demand for compactness.

  In the exhaust system for an engine according to another aspect of the present invention, in the above aspect, the flow velocity reduction portion is bulged with a partial region of the wall portion of the tubular member bulging toward the outside of the tube. It is a space region that is formed inward of the portion and temporarily retains the exhaust gas from the first exhaust pipe.

  In the exhaust system for an engine according to the above aspect, a space region in which the exhaust gas is once retained is formed as a flow rate reduction unit, so that the flow rate of the exhaust gas from the first exhaust pipe can be reduced with a simple configuration. This makes it possible to suppress the introduction of biased exhaust gas into the exhaust purification device.

  In the exhaust system for an engine according to another aspect of the present invention, in the above aspect, the first exhaust pipe is connected to an exhaust port of a first cylinder disposed at one end of the plurality of cylinders in the arrangement direction. The exhaust pipe has an opening at the tip end facing downward.

  In the engine exhaust apparatus according to the above aspect, the first exhaust pipe is an exhaust pipe connected to the exhaust port of the first cylinder arranged at one end in the cylinder row direction (the direction of the above arrangement), and thereby the tubular member Is extended from the center side or the other end side in the cylinder row direction toward the one end side. And since the front-end | tip part of the 1st exhaust pipe is inserted inward of the cylindrical member as mentioned above, at least the exhaust gas from the 1st exhaust pipe is the wall by the side of the said one end of a cylindrical member Try to flow along the inner surface.

  On the other hand, in this aspect, by providing the flow velocity reduction unit, it is possible to suppress the introduction of uneven exhaust gas to the exhaust purification device.

  In the engine exhaust system according to another aspect of the present invention, in the above aspect, the distal end portion of the first exhaust pipe is bent toward the bulging direction with respect to a vertical axis. Has been.

  In the engine exhaust apparatus according to the above aspect, the tip of the first exhaust pipe is bent toward the bulging direction, so that the exhaust gas from the first exhaust pipe is led out toward the flow velocity reduction unit. The flow velocity can be effectively reduced.

  In the exhaust system for an engine according to another aspect of the present invention, in the above aspect, the cylindrical member communicates with a merging cylinder portion where exhaust gases from the plurality of second exhaust pipes merge, and the merging cylinder portion. A downstream cylinder portion provided downstream of the exhaust gas in the flow direction, the downstream cylinder portion in the direction of the arrangement from the center of the plurality of cylinders The first end of the first exhaust pipe is disposed at a position that passes through the communication port and reaches the downstream cylinder.

  In the engine exhaust device according to the above aspect, exhaust gases from the plurality of second exhaust pipes are merged inside the merging cylinder portion, but exhaust gas from the first exhaust pipe is merged inside the downstream cylinder portion. Since it is derived | led-out, the pipe length of a 1st exhaust pipe can be ensured long while achieving compactness in the whole exhaust apparatus.

  In the engine exhaust apparatus according to another aspect of the present invention, in the above aspect, the first exhaust pipe passes through a position that is offset toward the one end side with respect to the communication port portion from the center of the communication port portion. doing.

  In the engine exhaust device according to the above aspect, the first exhaust pipe passes through the position offset toward the one end side with respect to the communication port portion from the center of the communication port portion. The opening area on the other end side in the cylinder row direction can be secured larger than that of the first exhaust pipe, and exhaust gas from exhaust pipes other than the first exhaust pipe can be efficiently guided to the downstream cylinder portion.

  In the engine exhaust device according to the above aspect, exhaust from the exhaust pipe other than the first exhaust pipe is made to the tube wall of the first exhaust pipe by passing the first exhaust pipe through the communication port. Gas can collide. Thereby, the flow velocity of exhaust gas from exhaust pipes other than the first exhaust pipe can also be reduced.

  In the engine exhaust system according to another aspect of the present invention, in the above aspect, the plurality of second exhaust pipes include a second cylinder and a third cylinder that follow the first cylinder in the direction of the arrangement of the plurality of cylinders. An exhaust pipe connected to each exhaust port of the cylinder.

  In the engine exhaust apparatus according to the above aspect, the plurality of second exhaust pipes are exhaust pipes connected to the exhaust ports of the second cylinder and the third cylinder. Even when such an aspect is adopted, it is possible to suppress exhaust interference and to introduce uneven exhaust gas into the exhaust purification device while reducing the size of the exhaust device.

  In the engine exhaust apparatus according to another aspect of the present invention, in the above aspect, the engine is a four-cylinder engine, and the fourth cylinder disposed at the other end in the direction of the arrangement of the plurality of cylinders. A fourth exhaust pipe connected to the exhaust port is further provided, and the fourth exhaust pipe is configured by a pipe member, and the tip of the fourth exhaust pipe has an opening at the tip. It is inserted in the said merging cylinder part so that it may be located inside the said merging cylinder part.

  In the exhaust system for an engine according to the above aspect, the fourth exhaust pipe connected to the exhaust port of the fourth cylinder disposed at the other end in the cylinder row direction is also configured with a pipe member, and the tip portion thereof is Since it is inserted inward of the merging cylinder portion, it is possible to suppress exhaust interference while reducing the size of the exhaust device.

  In the engine exhaust system according to another aspect of the present invention, in the above aspect, the merging cylinder portion extends in the direction of the arrangement, and the downstream cylinder portion is a region on the one end side in the arrangement direction. The opening that extends in the direction and is connected to the exhaust purification device is provided to face the other end side in the arrangement direction at the lower portion of the downstream cylindrical portion, and the exhaust purification device is It is arranged below the merging cylinder.

  In the engine exhaust device according to the above aspect, the flow of the exhaust gas inside the cylindrical member is substantially U-shaped in a side view from the side of the engine, and the opening faces the other end in the cylinder row direction. The exhaust gas is introduced into the exhaust purification device from the section. And as mentioned above, since the flow velocity reduction part is provided in the cylindrical member, the introduction | transduction of the biased exhaust gas with respect to an exhaust gas purification apparatus can be suppressed.

  Further, in the engine exhaust device according to the above aspect, the exhaust purification device is disposed below the merging cylinder portion, so that the peripheral configuration of the engine can be made compact.

  In the engine exhaust apparatus according to another aspect of the present invention, in the above aspect, a sensor head is provided on a portion of the cylindrical member that is opposite to the distal end portion of the first exhaust pipe with the flow velocity reduction portion interposed therebetween. An exhaust gas sensor is attached so that is located.

  In the exhaust system for an engine according to the above aspect, the exhaust gas sensor is attached so that the sensor head is located at a portion of the cylindrical member that is opposite to the tip of the first exhaust pipe across the flow velocity reduction portion. Therefore, it is possible to suppress only the exhaust gas from the first exhaust pipe from hitting the sensor head. From this, in the said aspect, the more exact state of exhaust gas can be grasped | ascertained.

  In the engine exhaust device according to each of the aspects described above, the exhaust interference can be suppressed and the uneven introduction of the exhaust gas into the exhaust purification device can be suppressed while meeting the demand for compactness.

1 is a schematic plan view showing configurations of an engine body 1 and an exhaust device 3 according to an embodiment. 2 is a schematic perspective view showing a configuration of an exhaust device 3. FIG. 3 is a schematic development view showing an internal configuration of the exhaust pipe 30. FIG. 2 is a schematic cross-sectional view showing an internal configuration of an exhaust pipe 30. FIG. It is a schematic cross section which expands and shows the B section of FIG. It is a schematic plan view which expands and shows the A section of FIG. 3 is a schematic cross-sectional view showing the flow of exhaust gas in the exhaust device 3. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The form described below is one embodiment of the present invention, and the present invention is not limited to the following form except for the essential configuration.

[Embodiment]
Embodiments will be described with reference to the drawings. In each figure, the X direction is the cylinder row direction of the engine, the Y direction is the width direction of the engine, and the Z direction is the vertical direction of the engine.

1. Overall Configuration The overall configuration of the engine body 1 and the exhaust device 3 according to the present embodiment will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, the engine body 1 is an inline 4-cylinder gasoline engine. In the engine body 1, # 1 cylinder 11, # 2 cylinder 12, # 3 cylinder 13, and # 4 cylinder 14 are arranged in order from the right side to the left side in the X direction. In the present embodiment, the ignition order in the engine body 1 is the order of # 1 cylinder 11 → # 3 cylinder 13 → # 4 cylinder 14 → # 2 cylinder 12.

  In FIG. 1, the cylinder head of the engine body 1 is viewed from above, and the upper side in the Y direction is the front side of the vehicle, and the lower side in the Y direction is the rear side of the vehicle.

  In the engine body 1, intake pipes 21 to 24 are connected to intake ports of the cylinders 11 to 14. The intake pipes 21 to 24 are # 1 intake pipe 21, # 2 intake pipe 22, # 3 intake pipe 23, and # 4 intake pipe 24 in order from the right side in the X direction.

  An exhaust device 3 is connected to the exhaust side of the engine body 1. As shown in FIGS. 1 and 2, the exhaust device 3 includes an exhaust pipe 30 and a fastening flange 40. The exhaust pipe 30 is composed of # 1 to # 4 exhaust pipes 31 to 34 connected to the exhaust ports of the cylinders 11 to 14.

  The # 2 exhaust pipe 32 and the # 3 exhaust pipe 33 are constituted by a cylindrical member 41 formed by a plurality of members 300 to 303 formed by pressing a plate material. As shown in FIG. 2, the cylindrical member 41 is formed of a merging cylinder portion 38 formed from a merging cylinder upper member 300 and a merging cylinder lower member 301, a downstream cylinder side member 302, and a downstream cylinder side member 303. And a downstream cylindrical portion 39. The joining cylinder part 38 is formed by joining the respective edges of the joining cylinder member 300 and the joining cylinder member 301 by welding or the like. Similarly, the downstream cylinder part 39 includes the downstream cylinder member 302 and the downstream cylinder member 303. Are joined together by welding or the like.

  The exhaust gas discharged through the inner exhaust passages of the # 2 exhaust pipe 32 and the # 3 exhaust pipe 33 joins the flow inside the merging cylinder portion 38 and flows to the downstream cylinder portion 39.

  Each of the # 1 exhaust pipe 31 and the # 4 exhaust pipe 34 is composed of a pipe member, and is bent into a predetermined shape. And each front-end | tip part of # 1 exhaust pipe 31 and # 4 exhaust pipe 34 is inserted in the inside of the cylindrical member 41 formed with the members 300-303.

In the exhaust device 3 according to the present embodiment, in the X direction, with respect to the center CL ₁ of cylinder row of the engine body 1, the downstream cylindrical portion 39 is arranged offset in the X direction right. In other words, the downstream cylindrical portion 39 is disposed in a biased manner in the portion corresponding to the # 1 cylinder 11 in the X direction. The downstream cylinder portion 39 is arranged in the vertical direction so as to be substantially along the Z direction in a portion corresponding to the # 1 cylinder 11 in the X direction.

As shown in FIG. 2, the distal end portion of the O ₂ sensor 35 is inserted into the downstream cylindrical portion 39 from the right side in the X direction at the lower portion in the Z direction. The downstream cylinder 39 is connected to a catalyst 36 that is an exhaust purification device on the downstream side in the exhaust gas flow direction. The external shape of the catalyst 36 is substantially cylindrical, and is arranged so as to extend in the X direction on the lower side in the Z direction of the merging tube portion 38.

  The catalyst 36 is connected to a GPF (Gasoline Particulate Filter) 37 at the left end portion in the X direction.

  The fastening flange 40 is for fastening the exhaust pipe 30 of the exhaust device 3 to the cylinder block of the engine body 1. And the front-end | tip part of the exhaust pipes 31-34 is inserted in the fastening flange 40. FIG. The exhaust pipes 31 to 34 are hermetically connected to the exhaust ports of the engine body 1 by fastening flanges 40.

  In the present embodiment, the exhaust pipe 30 is supported in a cantilever state by a portion fastened to the cylinder block using the fastening flange 40.

2. Internal Configuration of Exhaust Pipe 30 The internal configuration of the exhaust pipe 30 in the exhaust device 3 will be described with reference to FIGS. 3 and 4. FIG. 3 is a schematic development view showing the exhaust pipe 30 with the upper joining pipe member 300 removed, and FIG. 4 is a schematic cross-sectional view showing the exhaust pipe 30 with a part of the members cut away.

  As shown in FIG. 3, the joining cylinder lower member 301 constituting the joining cylinder part 38 is provided with a # 2 exhaust groove part 301 a in a part corresponding to the # 2 exhaust pipe 32, and a considerable number of parts in the # 3 exhaust pipe 33. Is provided with a # 3 exhaust groove 301b. The # 2 exhaust groove 301a communicates with the port side opening 32a, and the # 3 exhaust groove 301b communicates with the port side opening 33a.

  The port side opening 32a is connected to the exhaust port of the # 2 cylinder 12, and the port side opening 33a is connected to the exhaust port of the # 3 cylinder 13. The port-side opening 31a of the # 1 exhaust pipe 31 is connected to the exhaust port of the # 1 cylinder 11, and the port-side opening 34a of the # 4 exhaust pipe 34 is connected to the exhaust port of the # 4 cylinder 14.

  In addition, although illustration is abbreviate | omitted in FIG. 3, the merging cylinder upper member 300 is also press-processed by the substantially symmetrical shape with the merging cylinder lower member 301. FIG. A joining edge portion 301 c is provided on the outer edge of the joining tube lower member 301, and a joining edge portion is also provided on the outer edge of the joining tube upper member 300. The merging cylinder upper member 300 and the merging cylinder lower member 301 are joined airtightly at the joining edge portions 301c.

  As shown in FIG. 3, the location where the # 2 exhaust groove 301a and the # 3 exhaust groove 301b intersect, in other words, the joining location 38a where the exhaust gas from the # 2 exhaust pipe 32 and the # 3 exhaust pipe 33 merges, The communication port portion 301d is provided in a region on the left side in the X direction from the opening.

  As shown in FIGS. 3 and 4, the # 1 exhaust pipe 31 extends in the Y direction from a portion where the port side opening 31a is provided, and is bent in the Z direction at a portion where the communication port portion 301d is provided. . The distal end portion 31c of the # 1 exhaust pipe 31 is disposed at a position reaching the inside of the downstream cylindrical portion 39 below the communication port portion 301d in the Z direction. The tip 31c of the # 1 exhaust pipe 31 is slightly bent to the right in the X direction with respect to the axis along the Z direction (vertical direction). The tip side opening 31b of the # 1 exhaust pipe 31 is directed to a shelf 39c provided at the right side portion in the X direction of the downstream cylinder portion 39.

  The # 4 exhaust pipe 34 is curved in a U-shape or a V-shape with a downward convex shape in the Z direction (curved portion 34c) at the outer portion of the merging tube portion 38, and in the Z direction inside the merging tube portion 38. It has an upward convex shape and is curved in a U-shape or V-shape (curved portion 34d). The tip end portion 34 e of the # 4 exhaust pipe 34 is arranged so that the tip end opening 34 b faces the wall surface of the # 1 exhaust pipe 31.

  As shown in FIG. 4, the tip 34e of the # 4 exhaust pipe 34 is arranged closer to the communication port 301d than the junction 38a where the exhaust gases from the # 2 exhaust pipe 32 and the # 3 exhaust pipe 33 join. Has been. Specifically, the tip end portion 34e of the # 4 exhaust pipe 34 extends to a position closer to the communication port portion 301d than the joining point 38a.

  As shown in FIG. 4, the downstream cylinder portion 39 is provided with a catalyst side opening 39 a for connecting the catalyst 36. The catalyst side opening 39a is provided in a state facing the left side in the X direction.

A sensor attachment portion 39 b for attaching the O ₂ sensor 35 is provided on the wall portion on the right side in the X direction of the downstream cylinder portion 39. The O ₂ sensor 35 is disposed on the inner side of the downstream cylindrical portion 39 with the tip portion (sensor head) 35 a inserted through the sensor mounting portion 39 b.

  In addition, the shelf 39c in the downstream cylinder portion 39 is provided at a position between the tip opening 31b of the # 1 exhaust pipe 31 and the sensor mounting portion 39b in the Z direction.

3. Detailed Configuration of the Downstream Cylinder 39 and Routing of the # 1 Exhaust Pipe 31 The detailed configuration of the downstream cylinder 39 and the routing of the # 1 exhaust pipe 31 will be described with reference to FIGS. 5 and 6. 5 is an enlarged schematic cross-sectional view showing a portion B of FIG. 4, and FIG. 6 is an enlarged schematic plan view showing an A portion of FIG. 3.

  As shown in FIG. 5, the downstream cylindrical portion 39 is provided with a bulging portion 39e in which a part of the outer wall on the right side in the X direction is bulged to the right side in the X direction. The bulging portion 39e is formed at a location below the tip opening 31b in the # 1 exhaust pipe 31 in the Z direction and above the sensor mounting portion 39b in the Z direction.

  By providing the bulging portion 39e in the downstream cylindrical portion 39, the inner wall portion constitutes the shelf portion 39c, and inwardly below the tip side opening portion 31b in the # 1 exhaust pipe 31 in the Z direction. The volume part 39d which is a part of space is configured.

  The volume portion 39d in the downstream cylindrical portion 39 is a space region having a function of temporarily retaining the exhaust gas from the # 1 exhaust pipe 31, and the flow rate of the exhaust gas from the # 1 exhaust pipe 31 is reduced at that portion. . In other words, the volume portion 39d is a flow velocity reduction portion for the exhaust gas from the # 1 exhaust pipe 31.

Here, the bulging part 39e in the downstream cylinder part 39 is provided so that the surface L _39c of the shelf part 39c of the inner wall forms an angle θ ₃ with respect to the horizontal plane L _H. The angle θ ₃ is, for example, in the range of about 15 ° to 60 ° (as an example, 30 ° to 35 °).

As shown in FIG. 6, the tube center _{CL 31c} of # 1 exhaust pipe 31, the X direction of the center _{CL 301d} in communication mouth 301d, in the X-direction (side of the cylinder row direction of one end) by _{G 2} It is in an offset state. As a result, the communication port portion 301d is provided with a relatively large opening on the left side in the X direction of the # 1 exhaust pipe 31 (on the other end side in the cylinder row direction). G ₂ is, for example, in the range of 5 mm to 25 mm.

  The exhaust gas from the # 2 exhaust pipe 32 to the # 4 exhaust pipe 34 collides with the portion on the left side in the X direction on the tube wall of the # 1 exhaust pipe 31 at the communication port portion 301d and is guided to the downstream cylindrical portion 39. For this reason, the exhaust gas from the # 2 exhaust pipe 32 to the # 4 exhaust pipe 34 is also led to the downstream cylindrical portion 39 in a state where the flow velocity is reduced by the collision with the pipe wall of the # 1 exhaust pipe 31.

Returning to FIG. 5, in the # 1 exhaust pipe 31, the pipe axis CL ₃₁ is along the substantially vertical direction at a portion near the communication port portion 301 d in the downstream cylindrical portion 39. On the other hand, the tube axis CL _31c of the tip portion 31c of the # 1 exhaust pipe 31 is bent by an angle θ _{1 with} respect to the tube axis CL ₃₁ . More specifically, the distal end portion 31c of the # 1 exhaust pipe 31 (a shaft along the vertical direction, substantially the same as the tube axis CL ₃₁₎ vertical axis with respect to, X-direction right side (cylinder row direction of the end It is bent towards the side. Thereby, the opening surface L _31b of the tip side opening 31b of the # 1 exhaust pipe 31 forms an angle θ ₂ with respect to the horizontal plane L _H. The angle θ ₁ and the angle θ ₂ are, for example, in the range of about 10 ° to 30 ° (for example, 10 ° to 15 °).

The sensor mounting portion 39b in the downstream cylinder portion 39 is provided below the Z direction with respect to the portion where the bulging portion 39e is provided. In addition, the sensor attachment portion 39b has a center line CL ₃₅ of the tip portion (sensor head) 35a (portion indicated by arrow C) of the attached O ₂ sensor 35 with respect to the opening center CL _39a of the catalyst side opening _39a . It is provided so as to be lower in the Z direction. Incidentally, the difference between the center line _{CL 35} and opening center _{CL 39a} has a _{G 1.} The difference _{G 1} is, for example, in the range of 0Mm～40mm.

4). Exhaust Gas Flow in Exhaust Device 3 The exhaust gas flow in the exhaust device 3 will be described with reference to FIG. FIG. 7 is a schematic cross-sectional view schematically showing the flow of exhaust gas in the exhaust device 3.

As shown in FIG. 7, the exhaust gas F ₁ flowing through the # 4 exhaust pipe 34 is discharged from the front end portion 34 e through the front end side opening 34 b to the inside of the merged cylinder portion 38. Then, a part (residual part) of the exhaust gas from the # 2 exhaust pipe 32 and the # 3 exhaust pipe 33 discharged before and after timing is merged. Exhaust gas _{F 2} that merge impinges on X-direction left portion of the wall 31d of the # 1 exhaust pipe 31 in communication mouth 301d.

The exhaust gas F ₃ whose flow velocity has been reduced by colliding with the pipe wall 31d of the # 1 exhaust pipe 31 passes through the communication port portion 301d to the inner space of the downstream cylinder portion 39 (downstream cylinder inner space 39f). be introduced.

On the other hand, the exhaust gas F ₄ that has flowed through the # 1 exhaust pipe 31 is discharged from the front end side opening 31b disposed inside the downstream cylinder portion 39 to the downstream cylinder space 39f of the downstream cylinder portion 39. The exhaust gas discharged from the distal end side opening 31b is reduced in flow rate by the volume portion 39d provided immediately below the distal end side opening 31b. In addition, a part of the exhaust gas discharged from the front end side opening 31b collides with the shelf 39c and changes the flow direction (exhaust gas F ₅ ).

The exhaust gas F ₅ merges with a part (residual portion) of the exhaust gas F ₃ flowing before and after the timing, and is directed from the catalyst side opening 39a toward the catalyst 36 (not shown in FIG. 7). It is discharged (exhaust gas F ₆ ).

5. Effect Since the exhaust device 3 according to the present embodiment includes the # 1 exhaust pipe 31 configured by the pipe member, and the # 2 exhaust pipe 32 and the # 3 exhaust pipe 33 configured by the cylindrical member 41, all of them are provided. The exhaust device can be made more compact than when the exhaust pipe is configured with a pipe member or when all the exhaust pipes are configured with a cylindrical member.

  In the engine exhaust system according to the above aspect, the tip portion 31c of the # 1 exhaust pipe 31 is connected to the joining portion 38a (the exhaust gas from the # 2 exhaust pipe 32 and the # 3 exhaust gas) in the joining cylinder portion 38 of the cylindrical member 41. The exhaust gas from the # 1 cylinder 11 (from the # 1 exhaust pipe 31) is inserted to the downstream cylinder portion 39, which is downstream of the exhaust gas flow direction from the place where the exhaust gas from the pipe merges). Exhaust interference between the exhaust gas) and the exhaust gas from the # 3 cylinder 13 (exhaust gas from the # 3 exhaust pipe 33) that continues in the order of combustion can be suppressed.

Further, in the exhaust device 3 according to the present embodiment, the downstream cylindrical portion 39 of the cylindrical member 41 is provided with a flow velocity reducing portion (volume portion 39d), and the exhaust gas from the # 1 exhaust pipe 31 is provided at the volume portion 39d. Since the flow velocity of F ₄ is reduced, the bias toward the exhaust purification device (catalyst 36) due to the exhaust gas F ₄ from the # 1 exhaust pipe 31 in which the tip end portion 31c is inserted into the downstream cylindrical portion 39 of the cylindrical member 41 is provided. The introduction of exhaust gas is suppressed.

  Therefore, in the exhaust device 3 according to the present embodiment, it is possible to suppress the exhaust interference and the uneven introduction of the exhaust gas to the exhaust purification device (catalyst 36) while meeting the demand for compactness.

Further, in the exhaust device 3 according to the present embodiment, the formation of the bulging portion 39e forms a shelf portion 39c immediately below the distal end side opening 31b of the # 1 exhaust pipe 31, and from the # 1 exhaust pipe 31 The exhaust gas F ₄ can be temporarily retained, and the direction of a part of the exhaust gas F ₄ can be changed. Also by this, in this embodiment, the introduction of the biased exhaust gas to the catalyst 36 can be suppressed.

Further, in the exhaust device 3 according to the present embodiment, the # 1 exhaust pipe is an exhaust pipe connected to the exhaust port of the # 1 cylinder 11 arranged at one end in the cylinder row direction (right end in the X direction). The joining cylinder part 38 in the cylindrical member 41 is extended from the left side to the right side in the X direction. As described above, since the front end portion 31c of the # 1 exhaust pipe 31 is inserted inwardly of the downstream cylindrical portion 39, the exhaust gas F ₄ from at least # 1 exhaust pipe 31, the downstream cylindrical portion 39 To flow along the wall inner surface on the right side in the X direction.

  On the other hand, in the present embodiment, by providing the volume portion 39d, it is possible to suppress the introduction of the biased exhaust gas to the catalyst 36.

Further, in the exhaust device 3 according to the present embodiment, the tip portion 31c of the # 1 exhaust pipe 31 is bent to the right in the X direction (toward the bulging direction), so the exhaust gas from the # 1 exhaust pipe 31 is bent. F ₄ is derived toward the volume 39d (flow rate reducing section), it can be effectively reduced flow rate.

Further, in the exhaust device 3 according to the present embodiment, the exhaust gas from the # 2 exhaust pipe 32 and the # 3 exhaust pipe 33 is merged inside the merging cylinder portion 38, but the exhaust gas from the # 1 exhaust pipe 31 Since F ₄ is led out inward of the downstream cylindrical portion 39, the length of the # 1 exhaust pipe 31 can be ensured to be long while achieving compactness in the entire exhaust device 3. Interference can be suppressed.

Further, in the exhaust device 3 according to the present embodiment, in the communication port portion 301d of the tubular member 41, the tube center CL _31c of the # 1 exhaust pipe 31 is X more than the center CL _{301d in} the X direction of the communication port portion 301d. Since it is arranged at a position offset to the right side in the direction (one end side in the cylinder row direction), the opening area on the left side in the X direction (the other end side in the cylinder row direction) from the # 1 exhaust pipe 31 in the communication port portion 301d is arranged. The exhaust gas from the # 2 to # 4 exhaust pipes 32 to 34 can be efficiently guided to the downstream cylindrical portion 39.

Further, in the exhaust device 3 according to the present embodiment, by passing the # 1 exhaust pipe 31 through the communication port portion 301d, the # 2 to # 4 exhaust pipes are provided to the tube wall 31d of the # 1 exhaust pipe 31. it can collide with exhaust gas _{F 2} from 32 to 34. Thus, it is possible to also reduce the flow rate of the exhaust gas _{F 2} from # 2 to # 4 exhaust pipe 32 to 34.

  Further, in the exhaust device 3 according to the present embodiment, the # 2 exhaust pipe 32 and the # 3 exhaust pipe 33 connected to the exhaust ports of the # 2 cylinder 12 and the # 3 cylinder 14 arranged in the center part in the cylinder row direction. Is constituted by the cylindrical member 41, so that the exhaust device 3 can be made compact as compared with the case where these are constituted by the pipe member.

  In the exhaust device 3 according to this embodiment, the # 4 exhaust pipe 34 connected to the exhaust port of the # 4 cylinder 14 arranged at the left end in the X direction (the other end in the cylinder row direction) also includes a pipe member. Since the tip 34e is inserted inward of the merging cylinder 38, the exhaust device 3 can be made compact while maintaining the tube length of the # 4 exhaust pipe 34. Suppression can be achieved.

  Further, in the exhaust device 3 according to the present embodiment, the flow of the exhaust gas inside the cylindrical member 3 is substantially U-shaped in a side view from the Y direction (engine side). Specifically, as shown in FIG. 4 and the like, the exhaust gas in the # 2 to # 4 exhaust pipes 32 to 34 flows from the left side to the right side in the X direction in the merging cylinder portion 38, and the communication port portion 301d. The direction of the flow is changed downward in the Z direction, and is led out from the catalyst side opening 39a of the downstream cylinder portion 39 toward the catalyst 36 on the right side in the X direction. The exhaust gas in the # 1 exhaust pipe 31 flows in the pipe of the # 1 exhaust pipe 31 downward in the Z direction, and is led out from the catalyst side opening 39a of the downstream cylinder portion 39 toward the catalyst 36 on the right side in the X direction. The

  When a U-shaped flow occurs as described above, many components of the exhaust gas tend to flow in the outer portion of the swirl in an uneven manner. In the present embodiment, the volume portion 39d ( Since the flow rate of the exhaust gas is reduced and the flow unevenness is reduced, the exhaust gas is discharged to the catalyst 36. Therefore, uneven introduction of exhaust gas to the catalyst 36 can be suppressed.

  Further, in the exhaust device 3 according to the present embodiment, the catalyst 36 is disposed below the merging cylinder portion 38 in the Z direction, so that a compact layout of the peripheral configuration of the engine body 1 can be realized.

Further, in the exhaust device 3 according to the present embodiment, in the downstream cylindrical portion 39 of the cylindrical member 41, the tip portion 31c of the # 1 exhaust pipe 31 sandwiching the bulging portion 39e is on a portion opposite to the Z direction. Since the O ₂ sensor (exhaust gas sensor) 35 is attached so that the front end (sensor head) 35a is positioned, only the exhaust gas from the # 1 exhaust pipe 31 is the front end (sensor head) 35a of the O ₂ sensor 35. Can be suppressed. Thus, in the present embodiment, a more accurate exhaust gas state can be grasped.

[Modification]
In the above embodiment, an in-line four-cylinder gasoline engine is adopted as an example of the engine body 1, but the present invention is not limited to this. For example, a diesel engine can be adopted as the type of engine.

  Further, the number of cylinders in the engine may be 3 cylinders or 5 cylinders or more. In this case, the number of exhaust pipes is also a number corresponding to the number of cylinders.

  In addition, the type of engine is not limited to being in series, and a V type or a W type may be employed.

In the above embodiment employs the downstream cylindrical portion 39 of the tubular member 41, in the X direction (the cylinder row direction), a mode of offset # 1 cylinder 11 side with respect to the center CL ₁ of cylinder row as an example However, the present invention is not limited to this. For example, the downstream cylindrical portion 39 of the tubular member, in the X direction (the cylinder row direction), as to be arranged offset to the # 4 cylinder 14 side opposite to the # 1 cylinder 11 with respect to the center CL ₁ of cylinder row Also good. In this case, instead of the # 1 exhaust pipe 31, the same effect as the above embodiment can be obtained by adopting a form in which the tip part of the # 4 exhaust pipe is inserted to the inside of the downstream cylinder part. .

  Moreover, in the said embodiment, although the cylindrical member 41 was comprised with four board | plate materials (Joint pipe | tube upper member 300, the merging pipe | tube lower member 301, the downstream pipe | tube side member 302, the downstream pipe | tube side member 303), The invention is not limited to this. For example, the merging cylinder upper member 300 and the merging cylinder lower member 301 constituting the merging cylinder portion 38 may be extended, and the downstream cylinder portion may be configured by the extended portions. That is, the cylindrical member composed of the merging cylinder portion and the downstream cylinder portion may be configured by a combination of two pressed plates. In the case of adopting such a modified example, a cylindrical member composed of a merging cylinder part and a downstream cylinder part can be integrally formed with two plate members, so that the number of parts can be reduced. Therefore, complicated parts management during manufacturing can be suppressed. In addition, when the above modification is adopted, the number of man-hours such as joining each other is reduced by integrally forming the merging tube portion and the downstream tube portion as compared with the case where they are formed as separate parts. The manufacturing cost can be reduced.

  Further, the number of plate members constituting the cylindrical member may be 5 or more.

  In the above-described embodiment, all of the four plate members (joining tube upper member 300, joining tube lower member 301, downstream tube side member 302, and downstream tube side member 303) are pressed. The invention is not limited to this. For example, it is possible to configure the merging tube portion and the downstream tube portion by combining a plate material subjected to press work and a flat plate material not subjected to press work.

  In the above embodiment, as described with reference to FIG. 4, the two curved portions 34 c and 34 d are provided in the portion of the # 4 exhaust pipe 34 inserted into the merging cylinder portion 38. The invention is not limited to this. If it is not necessary to increase the pipe length, the # 4 exhaust pipe can be formed to extend linearly.

  Moreover, in the said embodiment, although it decided to provide so that the cylinder axis of the downstream cylinder part 39 may follow a Z direction, this invention is not limited to this. For example, an annular ring having an arcuate cylindrical axis can be employed as the downstream cylindrical portion.

DESCRIPTION OF SYMBOLS 1 Engine main body 3 Exhaust device 30 Exhaust pipe 31 # 1 Exhaust pipe 31b Tip side opening part 31c Tip part 32 # 2 Exhaust pipe 33 # 3 Exhaust pipe 34 # 4 Exhaust pipe 34b Tip side opening part 34e Tip part 35 O ₂ sensor ( Exhaust gas sensor)
36 Catalyst (Exhaust gas purification device)
37 GPF
38 confluence cylinder part 39 downstream cylinder part 39a catalyst side opening part 39c shelf part 39d volume part (flow velocity reduction part)
39e bulging portion 39f downstream cylinder space 41 cylindrical member

Claims (10)

In an exhaust system of an engine, which is connected to an exhaust port of an engine in which a plurality of cylinders are arranged in series, and an exhaust purification device is connected to a downstream end portion in the exhaust gas flow direction,
A first exhaust pipe connected to an exhaust port of one of the plurality of cylinders;
A plurality of second exhaust pipes connected to the exhaust ports of at least two cylinders excluding the one cylinder among the plurality of cylinders;
With
The first exhaust pipe is configured with a pipe member,
The plurality of second exhaust pipes are formed of a plurality of plate materials obtained by press-molding at least some of the plate materials, and include a cylindrical member to which exhaust gases from the plurality of second exhaust pipes merge. Configured,
The exhaust purification device is connected to an opening provided at a downstream end of the tubular member in the flow direction of the exhaust gas, and is arranged to extend in the arrangement direction of the plurality of cylinders.
The distal end portion of the first exhaust pipe is inserted to a downstream side in the exhaust gas flow direction from a location where the exhaust gas from the plurality of second exhaust pipes in the cylindrical member merges,
The cylindrical member is provided with a flow rate reduction unit that reduces the flow rate of the exhaust gas from the first exhaust pipe at a portion where the opening of the tip of the first exhaust pipe is located.
Engine exhaust system. The engine exhaust device according to claim 1,
The flow velocity reduction part is formed inwardly of a part of the wall of the tubular member toward the outside of the cylinder, and is formed inside the bulged part, and exhaust gas from the first exhaust pipe Is a space area where
Engine exhaust system. An exhaust system for an engine according to claim 2,
The first exhaust pipe is an exhaust pipe connected to an exhaust port of a first cylinder disposed at one end of the plurality of cylinders in the arrangement direction, and an opening of the tip portion faces downward. Yes,
Engine exhaust system. An exhaust system for an engine according to claim 3,
The distal end portion of the first exhaust pipe has a tube axis of the distal end portion bent toward the bulging direction with respect to a vertical axis.
Engine exhaust system. An exhaust system for an engine according to claim 3 or claim 4,
The cylindrical member is continuous with a merging cylinder portion where exhaust gases from the plurality of second exhaust pipes merge, and a downstream side in the exhaust gas flow direction with respect to the merging cylinder portion via a communication port portion. A downstream cylinder portion provided in the
The downstream cylinder portion is disposed offset from the center of the plurality of cylinders on the one end side in the arrangement direction,
The tip of the first exhaust pipe is disposed at a position that passes through the communication port and reaches the downstream cylinder,
Engine exhaust system. An exhaust system for an engine according to claim 5,
The first exhaust pipe passes through a position offset to the one end side with respect to the communication port portion from the center of the communication port portion.
Engine exhaust system. The engine exhaust device according to claim 5 or 6,
The plurality of second exhaust pipes are exhaust pipes connected to the exhaust ports of the second cylinder and the third cylinder following the first cylinder in the arrangement direction of the plurality of cylinders.
Engine exhaust system. An exhaust system for an engine according to claim 7,
The engine is a 4-cylinder engine,
A fourth exhaust pipe connected to an exhaust port of a fourth cylinder disposed at the other end of the plurality of cylinders in the arrangement direction;
The fourth exhaust pipe is configured with a pipe member,
The distal end portion of the fourth exhaust pipe is inserted into the merging cylinder portion so that the opening portion of the distal end portion is located inward of the merging cylinder portion.
Engine exhaust system. An engine exhaust device according to any one of claims 5 to 8,
The merging tube portion extends in the direction of the arrangement,
The downstream cylindrical portion extends in the vertical direction in the region on the one end side in the direction of the arrangement,
The opening to which the exhaust purification device is connected is provided at the lower part of the downstream cylinder part so as to face the other end side in the direction of the arrangement,
The exhaust purification device is disposed below the merging cylinder portion.
Engine exhaust system. An engine exhaust device according to any one of claims 1 to 9,
An exhaust gas sensor is attached to the cylindrical member so that a sensor head is located on a portion opposite to the tip portion of the first exhaust pipe across the flow velocity reduction portion.
Engine exhaust system.

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