JP2018178776A - Exhaust system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust system capable of reliably and continuously purifying exhaust gas while suppressing the temperature drop of a catalyst.SOLUTION: An exhaust system 1 for purifying exhaust gas exhausted from an internal combustion engine 2 includes exhaust ports 2c, 2d, 2e, 2f for exhausting gas combusted in the internal combustion engine 2 in a perpendicular direction B perpendicular to a longitudinal direction A of the internal combustion engine 2, a catalyst 7a extending in the longitudinal direction A of the internal combustion engine 2, and an exhaust passage through which the exhaust gas exhausted from the exhaust ports 2c, 2d, 2e, 2f flows to the catalyst 7a, the exhaust passage having curve parts 10a, 11a for curving the exhaust gas exhausted from the exhaust ports 2c, 2d, 2e, 2f to flow from the perpendicular direction B to the longitudinal direction A, and extension parts 10b, 11b provided on the exhaust-gas-passing-direction downstream side of the curve parts 10a, 11a and extending while being connected to the curve parts 10a, 11a, respectively, the extension parts 10b, 11b being arranged extending along the catalyst 7a in the longitudinal direction A.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an exhaust system of a multi-cylinder internal combustion engine having a plurality of exhaust pipes and a catalyst connected thereto.

2. Description of the Related Art An exhaust system is known which exhausts exhaust gases discharged from a plurality of cylinders of a multi-cylinder internal combustion engine after the catalyst is cleaned.
In such an exhaust system, since the catalyst used for exhaust purification does not function unless the temperature is raised to a predetermined temperature or more, the exhaust from each cylinder is collected in the collecting portion and then the hot exhaust is applied to the catalyst. In order to immediately put the exhaust into the catalyst from the junction.

  In the above-described technology, in order to further miniaturize the exhaust system, a technology has been proposed in which the catalyst is disposed in such a direction that the center line of the catalyst disposed immediately downstream of the exhaust collecting portion is perpendicular to the engine wall surface. (For example, refer to "patent document 1").

JP, 2016-75264, A

In the above-described technology, the catalyst after exhaust gas escapes is air cooled by the outside air, so that the temperature of the catalyst decreases before the next exhaust gas is sent, and the function of the catalyst is not sufficiently exerted to clean the exhaust gas. Has a problem in that
An object of the present invention is to solve the above-mentioned problems, and to provide an exhaust system capable of reliably and continuously purifying exhaust by suppressing a temperature decrease of a catalyst.

  The invention according to claim 1 is an exhaust system for purifying exhaust gas discharged from an internal combustion engine, wherein the exhaust port exhausts gas burned by the internal combustion engine in a direction orthogonal to a longitudinal direction of the internal combustion engine; A catalyst extending in the longitudinal direction of the internal combustion engine and an exhaust passage for flowing exhaust gas discharged from the exhaust port to the catalyst are provided, and the exhaust gas passage discharges the exhaust gas discharged from the exhaust port from the orthogonal direction The catalyst includes: a bent portion which is bent to flow in the longitudinal direction; and an extending portion which is provided on the downstream side of the bent portion in the exhaust gas passing direction and extends to be connected to the bent portion. Extending along the longitudinal direction.

  The invention according to claim 2 is the exhaust system according to claim 1, wherein the central axis of the catalyst is disposed closer to the internal combustion engine than the central axis of the extension.

  The invention according to claim 3 is characterized in that in the exhaust system according to claim 1 or 2, the extension portion is provided so as to cover a half or more in the longitudinal direction of the catalyst.

  According to a fourth aspect of the present invention, in the exhaust system according to any one of the first to third aspects, the internal combustion engine further includes a plurality of cylinders, and the exhaust passage is at least one of the plurality of cylinders. It has a collecting part which collects the exhaust_gas | exhaustion discharged | emitted from two cylinders, It is characterized by the said bending part being arrange | positioned downstream of the exhaust passage direction of the said collecting part.

  The invention according to claim 5 is characterized in that, in the exhaust system according to claim 4, the collecting portion is disposed on the top of the catalyst.

  According to a sixth aspect of the present invention, in the exhaust system according to any one of the first to fifth aspects, the plurality of cylinders are four or more cylinders, and the exhaust passage is at least one of the plurality of cylinders. A first collecting portion for collecting exhausts discharged from two cylinders; a second collecting portion for collecting exhausts discharged from at least another two cylinders different from the two cylinders among the plurality of cylinders; A first bent portion disposed downstream of the collecting portion in the exhaust passage direction and causing exhaust gas flowing from the first collecting portion to flow in the longitudinal direction of the internal combustion engine; and an exhaust passage direction downstream side of the first bent portion And extending in the exhaust passage direction of the second collecting portion and extending in the exhaust flow direction from the second collecting portion. A second bent portion to be bent to flow into the A second extending portion disposed downstream of the second bending portion in the exhaust gas passage direction and extending in connection with the second bending portion, the first extending portion extending along the catalyst It is characterized in that it is disposed extending in the longitudinal direction, and the second extending part is disposed extending in the longitudinal direction along the first extending part.

  According to the present invention, since the extending portion is disposed to extend in the longitudinal direction in the manner along the catalyst, the heat of the exhaust passing through the extending portion can heat the catalyst, and the next exhaust It is possible to provide an exhaust system capable of reliably and continuously purifying exhaust by preventing the temperature of the catalyst from lowering before being sent and the purification of the exhaust being inhibited.

FIG. 1 is a schematic perspective view of an exhaust system to which an embodiment of the present invention is applied. It is a schematic top view of the exhaust system to which one embodiment of the present invention is applied. FIG. 1 is a schematic front view of an exhaust system to which an embodiment of the present invention is applied. FIG. 1 is a schematic side view of an exhaust system to which an embodiment of the present invention is applied. It is a schematic perspective view of the exhaust system which applied other embodiment of this invention.

1 shows a schematic perspective view of an exhaust system to which an embodiment of the present invention is applied, FIG. 2 shows a top view, FIG. 3 shows a front view, and FIG. 4 shows a side view. In the figure, an exhaust system 1 is attached to a wall surface 2b of a cylinder head 2a of a four-cylinder engine 2 which is an internal combustion engine.
Exhaust from the four-cylinder engine 2 is performed in the order of the first cylinder, the third cylinder, the fourth cylinder, and the second cylinder in the present embodiment.

The exhaust system 1 includes a first exhaust pipe 3 connected to the exhaust port 2c of the first cylinder formed in the cylinder head 2a, and a second exhaust pipe 4 connected to the exhaust port 2d of the second cylinder, the third cylinder The third exhaust pipe 5 is connected to the exhaust port 2e, the fourth exhaust pipe 6 is connected to the exhaust port 2f of the fourth cylinder, and the catalytic converter 7 is provided with a catalyst 7a for purifying the exhaust gas.
Each exhaust port 2c, 2d, 2e, 2f is orthogonal to the longitudinal direction A of the four-cylinder engine 2 indicated by the double arrow in FIG. 1, respectively, in the orthogonal direction B indicated by the double arrow in FIG. Exhaust the burned gas inside as exhaust. Each exhaust pipe 3, 4, 5, 6 constitutes an exhaust passage.

  Each exhaust pipe 3, 4, 5, 6 is attached to the wall 2b in a state where one end of each exhaust pipe is connected to the exhaust port 2c, 2d, 2e, 2f of the corresponding cylinder through the flange member 14. The other ends of the exhaust pipes 3 and 6 are respectively attached to one end of a first collective exhaust pipe 8 which has a substantially Y-shape and functions as a first collecting portion which is a collecting portion. The other ends of the exhaust pipes 4 and 5 are respectively attached to one end of a second collecting exhaust pipe 9 which has the same shape as the first collecting exhaust pipe 8 and which functions as a second collecting portion which is a collecting portion.

The other end of the first exhaust pipe 3 is attached to one of the bifurcated ends of the first collective exhaust pipe 8, and the other end of the one end is connected to the first exhaust pipe 3. The other end of the fourth exhaust pipe 6 connected to the fourth cylinder to be exhausted in a discontinuous state with the cylinder is attached.
In the second collective exhaust pipe 9, the other end of the second exhaust pipe 4 is attached to one of the bifurcated ends, and the second exhaust pipe 4 is connected to the other of the one ends. The other end of the third exhaust pipe 5 connected to the third cylinder which is exhausted in a discontinuous state from the cylinder is attached.
Each of the collective exhaust pipes 8 and 9 constitutes an exhaust passage.

  One end of a fifth exhaust pipe 10 is attached to the other end of the first collective exhaust pipe 8. The fifth exhaust pipe 10 has a substantially L-shape, and as shown in FIG. 3, the exhaust gas discharged from the exhaust ports 2c and 2f and flowing in the orthogonal direction B through the exhaust pipes 3, 6, and 8 is elongated A first bent portion 10a as a bent portion to be bent in the direction A, and a first extended portion provided on the downstream side of the first bent portion 10a in the exhaust gas passing direction and connected to the first bent portion 10a And an extending portion 10b.

  One end of a sixth exhaust pipe 11 is attached to the other end of the second collective exhaust pipe 9. The sixth exhaust pipe 11, which has substantially the same shape as the fifth exhaust pipe 10, is discharged from the exhaust ports 2d and 2e and flows in the orthogonal direction B via the exhaust pipes 4, 5 and 9, as shown in FIG. A second bent portion 11a as a bent portion for bending the exhaust in the longitudinal direction A, and an extension portion provided on the downstream side of the second bent portion 11a in the exhaust passage direction and connected to the second bent portion 11a And the second extending portion 11 b of

The other end of the fifth exhaust pipe 10 and the other end of the sixth exhaust pipe 11 are respectively connected to one end of a seventh exhaust pipe 12 which constitutes an exhaust passage and has a bifurcated structure. The seventh exhaust pipe 12 having a substantially U-shape as shown in FIG. 2 is connected to the catalytic converter 7 at the other end, and the catalytic converter 7 is provided further downstream on the exhaust gas passing through the catalyst. An exhaust outlet 13 is provided which feeds the exhaust pipe.
The seventh exhaust pipe 12 travels in the longitudinal direction A through the exhaust pipes 10, 11 in the longitudinal direction A to the right in FIG. I am changing it. By the function of the seventh exhaust pipe 12, as shown in FIG. 1, FIG. 3 and FIG. 4, the catalytic converter 7 having the catalyst 7a below the collecting exhaust pipes 8, 9 and the exhaust pipes 10, 11 is disposed. be able to.
The extension portions 10b and 11b extend in the longitudinal direction A along the catalyst 7a, the extension portion 10b with respect to the catalyst 7a, and the extension portion 11b with respect to the extension portion 10b. It is arranged close.

According to the exhaust system 1 of the present invention having the above configuration, since the extending portions 10b and 11b are arranged to extend in the longitudinal direction A in a manner along the catalyst 7a, the extending portions 10b and 11b are passed. The heat of the exhaust can heat the catalyst 7a, and the temperature of the catalyst 7a is lowered before the next exhaust is sent to prevent the exhaust purification from being hindered, thereby ensuring the exhaust purification. And the exhaust system which can be performed continuously can be provided.
Moreover, the synergetic effect of heat retention and early temperature rise of the catalyst 7a can be obtained by transfer of heat between the extension parts 10b and 11b and the catalyst 7a.

Further, the first collective exhaust pipe 8 and the second collective exhaust in which the exhaust temperatures from the exhaust pipes 3, 4, 5 and 6 gather on the upstream side in the exhaust passage direction with respect to the extension parts 10b and 11b. Since the pipe 9 is provided, the heat retention property of the catalyst 7a can be further improved by passing the temperature-raised exhaust gas through the extension portions 10b and 11b.
Furthermore, in the above-described configuration, as shown in FIG. 3, the extending portions 10b and 11b are arranged to cover half or more of the length in the longitudinal direction of the catalyst 7a, that is, the longitudinal direction A. This configuration can further enhance the synergetic effect of the above-described heat retention and early temperature rise.

In the exhaust system 1 described above, as shown in FIG. 4, the central axis S of the catalyst 7a is shorter than the distance B from the central axis S1 of the first extension 10b to the wall 2b. In the catalyst 7a, the central axis S of the catalyst 7a is smaller than the central axes S1 and S2 of the extending portions 10b and 11b so that the distance C is smaller than the distance C from the central axis S2 of the second extending portion 11b to the wall surface 2b. It is placed close to the side.
With this configuration, the exhaust system 1 can be made compact as compared with the conventional configuration in which the catalytic converter 7 is disposed in the direction in which the axis S is perpendicular to the wall surface 2b, and the central axis S extends Since the catalyst 7a is disposed on the wall surface 2b side with respect to the central axes S1 and S2 of the portions 10b and 11b, the exhaust device 1 can be made more compact.

  Further, in the above configuration, since the first collecting exhaust pipe 8 where the temperature of the exhaust gas is high is disposed immediately above the catalyst 7a, the catalyst 7a can be warmed immediately and the function of the catalyst 7a can be expressed in a short time be able to. Further, since the second collecting exhaust pipe 9 in which the temperature of the exhaust gas is high is disposed above the first collecting exhaust pipe 8, the catalyst 7a is warmed by cooling the first collecting exhaust pipe 8 by the outside air. It can be prevented from being disturbed, and furthermore, the heat retention of the first collecting exhaust pipe 8 can also be performed.

In the above embodiment, the exhaust from the four exhaust pipes 3, 4, 5, 6 independently connected to the four cylinders of the cylinder head 2a is gathered by the two collective exhaust pipes 8, 9 After that, the configuration is shown in which the catalyst is sent to the catalytic converter 7 through the two exhaust pipes 10 and 11 and the seventh exhaust pipe 12.
However, the present invention is not limited to this configuration. For example, as shown in FIG. 5, the exhaust ports of the second and third cylinders are merged in the cylinder head 2a, and one end is connected to the exhaust port 2g of the first cylinder. First exhaust pipe 15, the second exhaust pipe 16 connecting one end to the collective exhaust port 2h of the second cylinder and the third cylinder, and the third exhaust pipe 17 connecting one end to the exhaust port 2i of the fourth cylinder A first collecting exhaust pipe 18 having a substantially Y-shape and functioning as a first collecting portion which is a collecting portion, a second collecting exhaust pipe 19 which functions as a second collecting portion which is a collecting portion, and a fourth exhaust pipe The present invention is also applicable to an exhaust system 21 having a catalytic converter 7 having a catalyst 20a, a catalyst 7a, and an exhaust outlet 13. The code | symbol A shown in FIG. 5 has each shown the longitudinal direction shown in FIG. 1, and the code | symbol B has shown the orthogonal direction, respectively.

  The other end of the first exhaust pipe 15 is attached to one of the bifurcated ends of the first collective exhaust pipe 18, and the first exhaust pipe 15 is connected to the other of the ends. The other end of the third exhaust pipe 17 connected to the fourth cylinder, which is exhausted in a discontinuous state with the cylinder, is attached. The other end of the second exhaust pipe 16 is attached to one end of the second collective exhaust pipe 19. Each collecting exhaust pipe 18, 19 has its other end attached to one end of a fourth exhaust pipe 20 having a bifurcated structure. Each exhaust pipe 15, 16, 17, 20 and each collecting exhaust pipe 18, 19 respectively constitute an exhaust passage.

The first collective exhaust pipe 18 is substantially L-shaped, and is a bent portion that bends the exhaust flowing from the respective exhaust ports 2g and 2i in the orthogonal direction B through the respective exhaust pipes 15 and 17 in the longitudinal direction A. And a first extending portion 18b as an extending portion provided downstream of the first bending portion 18a in the exhaust gas passing direction and extending to the first bending portion 18a. ing.
The second collective exhaust pipe 19 having substantially the same shape as the first collective exhaust pipe 18 is a bent portion that bends the exhaust flowing from the exhaust port 2 h in the orthogonal direction B via the second exhaust pipe 16 in the longitudinal direction A. And a second extending portion 19b as an extending portion provided on the downstream side of the second bending portion 19a in the exhaust gas passage direction and extending to the second bending portion 19a. ing.

The fourth exhaust pipe 20 travels the passing direction of the exhaust proceeding to the right in FIG. 5 in the longitudinal direction A via the respective collective exhaust pipes 18 and 19 to the left in FIG. Let me change it. By the action of the fourth exhaust pipe 20, the catalytic converter 7 having the catalyst 7a can be disposed below the respective collective exhaust pipes 18, 19.
The extensions 18b and 19b extend in the longitudinal direction A along the catalyst 7a, the extension 18b to the catalyst 7a, and the extension 19b to the extension 18b. It is arranged close.

According to the exhaust system 21 of the present invention having the above-described configuration, since the extending portions 18b and 19b extending in the longitudinal direction A are arranged in a manner along the catalyst 7a, the extending portions 18b and 19b are passed. The heat of the exhaust can heat the catalyst 7a, and the temperature of the catalyst 7a is lowered before the next exhaust is sent to prevent the exhaust purification from being hindered, thereby ensuring the exhaust purification. And the exhaust system which can be performed continuously can be provided.
In addition, the heat transfer between the extension portions 18b and 19b and the catalyst 7a can provide a synergetic effect of heat retention and early temperature rise of the catalyst 7a.

Further, the first bent portion 18a of the first collective exhaust pipe 18 and the exhaust temperature rise by the exhaust from the exhaust pipes 15, 16 and 17 being gathered on the upstream side in the exhaust passage direction with respect to the extension portions 18b and 19b. Since the second bent portion 19a of the second collecting exhaust pipe 19 is provided, that is, since the extending portions 18b and 19b are provided in the first collecting exhaust pipe 18 and the second collecting exhaust pipe 19, the temperature-increased exhaust extends The heat retention of the catalyst 7a can be further improved by passing the portions 18b and 19b.
Furthermore, in the above-described configuration, as shown in FIG. 5, the extending portions 18b and 19b are arranged to cover half or more of the length in the longitudinal direction of the catalyst 7a, that is, the longitudinal direction A. This configuration can further enhance the synergetic effect of the above-described heat retention and early temperature rise.

As mentioned above, although the preferable embodiment of this invention was described, this invention is not limited to the specific embodiment mentioned above, Unless it specifically limited by the above-mentioned description, it stated in the claim. Various modifications and changes are possible within the scope of the present invention.
For example, although a four-cylinder engine is shown as the internal combustion engine, the internal combustion engine is not limited to a four-cylinder engine, and may be any engine as long as it has two or more cylinders. In each embodiment, the catalytic converter 7 having the catalyst 7 a is disposed below the first collecting exhaust pipe 8, 18 which is the collecting portion, but the catalytic converter 7 is disposed above the second collecting exhaust pipe 9, 19. May be arranged.
The effects described in the embodiments of the present invention only list the most preferable effects resulting from the present invention, and the effects according to the present invention are not limited to those described in the embodiments of the present invention. .

1, 21: Exhaust system, 2: Internal combustion engine (4 cylinder engine), 2c, 2d, 2e, 2f, 2g, 2h, 2i: Exhaust port, 7a: Catalyst, 8, 18 · · · Assembly part, first assembly part (first collecting exhaust pipe), 9, 19 ... collecting part, second assembly part (second collecting exhaust pipe), 10a, 18a · · · bent part (first bending Part), 10b, 18b ... extension part (first extension part) 11a, 19a ... bent part (second bend part), 11b, 19b ... extension part (second extension part , A: longitudinal direction, B: orthogonal direction, S: central axis of catalyst 7a, S1: central axis of first extending portion 10b, S2: second extending portion 11b Central axis of

Claims (6)

In an exhaust system for purifying exhaust gas discharged from an internal combustion engine,
An exhaust port for exhausting gas burned in the internal combustion engine in a direction perpendicular to the longitudinal direction of the internal combustion engine, a catalyst extending in the longitudinal direction of the internal combustion engine, and exhaust gas discharged from the exhaust port And an exhaust passage for flowing to the catalyst,
The exhaust passage is provided at a bending portion for bending the exhaust gas discharged from the exhaust port to flow in the longitudinal direction from the orthogonal direction, and is provided downstream of the bending portion in the exhaust passage direction and connected to the bending portion to extend With the existing extension,
The exhaust unit is characterized in that the extension portion extends in the longitudinal direction along the catalyst. In the exhaust system according to claim 1,
An exhaust system characterized in that a central axis of the catalyst is disposed closer to the internal combustion engine than a central axis of the extending portion. In the exhaust system according to claim 1 or 2,
The exhaust unit is characterized in that the extending portion is provided to cover a half or more in a lengthwise direction of the catalyst. The exhaust system according to any one of claims 1 to 3.
The internal combustion engine has a plurality of cylinders, and the exhaust passage has a collecting portion for collecting the exhaust gas discharged from at least two cylinders of the plurality of cylinders.
The exhaust system according to claim 1, wherein the bent portion is disposed downstream of the collecting portion in the exhaust gas passage direction. In the exhaust system according to claim 4,
The exhaust unit according to claim 1, wherein the collecting unit is disposed above the catalyst. The exhaust system according to any one of claims 1 to 5,
The plurality of cylinders are four or more cylinders,
The exhaust passage is
A first collecting portion for collecting exhaust gases discharged from at least two cylinders of the plurality of cylinders, and a second collecting member for collecting exhaust gases discharged from at least another two cylinders of the plurality of cylinders different from the two cylinders An assembly,
A first bending portion disposed downstream of the first collecting portion in the exhaust gas passage direction and configured to cause the exhaust flowing from the first collecting portion to flow in the longitudinal direction of the internal combustion engine;
A first extension portion disposed downstream of the first bending portion in the exhaust gas passage direction and extending in connection with the first bending portion;
A second bent portion disposed downstream of the second collecting portion in the exhaust gas passage direction and configured to cause the exhaust flowing from the second collecting portion to flow in the longitudinal direction;
And a second extending portion disposed downstream of the second bending portion in the exhaust gas passage direction and extending in connection with the second bending portion.
The first extending portion is disposed extending in the longitudinal direction along the catalyst, and the second extending portion extends in the longitudinal direction along the first extending portion. An exhaust system characterized in that it is disposed.

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