Exhaust pipe structure

Abstract

To provide an exhaust pipe structure capable of suppressing deterioration in the exhaust emission control action of a catalyst.SOLUTION: An exhaust pipe structure 10 includes an exhaust path 100 through which exhaust gas from an internal combustion engine 2 flows, and a guide member 300 provided in the exhaust path 100 for guiding the exhaust gas toward a catalyst 5 that controls emissions of the exhaust gas. The exhaust path 100 has a turbocharger arrangement portion 110, an enlarged portion 140 that is provided downstream of the turbocharger arrangement portion 110 in the flow direction of the exhaust gas and has a flow passage area of the exhaust gas gradually increasing toward the downstream side in the flow direction, and a catalyst arrangement portion 150 connected to the downstream end of the enlarged portion 140. The guide member 300 is disposed in the enlarged portion 140 and guides the exhaust gas in a direction along a center line AX including the central axis of the enlarged portion 140 and in an outward direction in an orthogonal direction orthogonal to the center line AX.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an exhaust pipe structure. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open No. 2009-13865 discloses an exhaust gas purification device for an internal combustion engine, the device including an internal combustion engine, an exhaust passage, and a NOx catalyst. The exhaust passage is branched into a first exhaust passage and a second exhaust passage, a first turbocharger is disposed in the first exhaust passage, and a second turbocharger is disposed in the second exhaust passage. The first exhaust passage and the second exhaust passage join together downstream of the first turbocharger and the second turbocharger and upstream of the NOx catalyst. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-13865 A Summary of the Invention [Problem to be solved by the invention]

[0004] In an exhaust gas purification device for an internal combustion engine as described in JP 2009-13865 A, there are cases where a biased flow of exhaust gas occurs toward the catalyst. In such cases, stagnation occurs in the flow of exhaust gas upstream of the catalyst, and deposits accumulate near the stagnation, which may result in insufficient purification of the exhaust gas by the catalyst.

[0005] An object of the present invention is to provide an exhaust pipe structure that can suppress a decrease in the exhaust purification function of a catalyst. [Means for solving the problem]

[0006] An exhaust pipe structure according to one aspect of the present invention comprises an exhaust path through which exhaust from an internal combustion engine flows, and a guide member provided within the exhaust path and guiding the exhaust toward a catalyst that purifies the exhaust, wherein the exhaust path has a turbocharger mounting section in which a turbocharger can be disposed, an enlarged section provided downstream of the turbocharger mounting section in the exhaust flow direction and in which the flow path area of ​​the exhaust gradually increases downstream in the exhaust flow direction, and a catalyst mounting section connected to the downstream end of the enlarged section and in which the catalyst is disposed, and the guide member is disposed in the enlarged section and guides the exhaust in a direction along a center line including the central axis of the enlarged section, and in a direction toward the outside in a perpendicular direction perpendicular to the center line. Effect of the Invention

[0007] According to the present invention, it is possible to provide an exhaust pipe structure that can suppress a decrease in the exhaust purification function of the catalyst. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an internal combustion engine system including an exhaust pipe structure according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described with reference to the accompanying drawings, in which the same or corresponding components are designated by the same reference numerals.

[0010] Fig. 1 is a diagram that shows a schematic diagram of an internal combustion engine system including an exhaust pipe structure of one embodiment of the present invention. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. As shown in Fig. 1, the internal combustion engine system 1 includes an internal combustion engine 2, a turbocharger 3, another turbocharger 4 different from the turbocharger 3, a catalyst 5, and an exhaust pipe structure 10.

[0011] In this embodiment, the internal combustion engine 2 has a V-type two-bank structure. The turbocharger 3, the other turbocharger 4, and the catalyst 5 are attached to an exhaust pipe structure 10. In this embodiment, the turbocharger 3 is set as a primary turbocharger, and the other turbocharger 4 is set as a secondary turbocharger. The catalyst 5 purifies the exhaust gas from the internal combustion engine 2. An example of the catalyst 5 is an oxidation catalyst (DOC).

[0012] The exhaust pipe structure 10 is connected to an internal combustion engine 2. The exhaust pipe structure 10 includes an exhaust path 100, a switching member 200, and a guide member 300.

[0013] The exhaust path 100 is connected to the internal combustion engine 2, and exhaust gas from the internal combustion engine 2 flows through the exhaust path 100. The exhaust path 100 has a turbocharger mounting section 110, another turbocharger mounting section 120, a junction section 130, an expansion section 140, and a catalyst mounting section 150.

[0014] The turbocharger mounting portion 110 is a portion where a turbocharger 3 can be mounted. The other turbocharger mounting portion 120 is a portion where another turbocharger 4 can be mounted. The other turbocharger mounting portion 120 is connected to the internal combustion engine 2 so as to be in parallel with the turbocharger mounting portion 110.

[0015] The junction 130 is formed downstream of the turbocharger mounting portion 110 and the other turbocharger mounting portion 120. The junction 130 merges the exhaust gas that has passed through the turbocharger mounting portion 110 and the exhaust gas that has passed through the other turbocharger mounting portion 120.

[0016] The expansion section 140 is provided downstream of the turbocharger mounting section 110 in the exhaust flow direction. More specifically, the expansion section 140 is connected to a downstream end of the junction section 130 in the exhaust flow direction. In other words, the junction section 130 is formed downstream of the turbocharger mounting section 110 and the other turbocharger mounting section 120 and upstream of the expansion section 140. The expansion section 140 has a flow passage area for the exhaust gas that gradually increases downstream in the exhaust flow direction.

[0017] The catalyst placement section 150 is connected to the downstream end of the expansion section 140. The catalyst placement section 150 is capable of placing a catalyst 5. The catalyst placement section 150 may be formed in a cylindrical shape. The inner diameter of the catalyst placement section 150 may be formed to be constant.

[0018] The switching member 200 is provided in the exhaust path 100. As shown in Fig. 1, the switching member 200 is provided, for example, in a portion of the other turbocharger mounting portion 120 downstream of a portion where the other turbocharger 4 is located. The switching member 200 is switchable between a first state in which the exhaust gas flows only to the turbocharger mounting portion 110 and a second state in which the exhaust gas flows to both the turbocharger mounting portion 110 and the other turbocharger mounting portion 120. The switching member 200 is formed of, for example, a switching valve. In this case, a state in which the switching valve is closed corresponds to the first state, and a state in which the switching valve is open corresponds to the second state.

[0019] When the switching member 200 is in the first state, the exhaust gas passes only through the turbocharger mounting portion 110, which makes it easy for a drift in the exhaust gas to occur in the expansion portion 140. The guide member 300 is a member that suppresses the occurrence of such a drift. In other words, the guide member 300 is particularly effective when the switching member 200 is in the first state. However, the guide member 300 can also suppress the occurrence of a drift when the switching member 200 is in the second state.

[0020] The guide member 300 is provided in the exhaust path 100. More specifically, the guide member 300 is disposed in the enlarged portion 140. The guide member 300 guides the exhaust gas toward the catalyst 5. The guide member 300 guides the exhaust gas in a direction along a center line AX (see FIG. 1) including the central axis of the enlarged portion 140 and in a direction toward the outside in a direction perpendicular to the center line AX. In other words, the guide member 300 guides the exhaust gas to a region of the catalyst 5 near the center line AX and to a region on the outside in the direction perpendicular to the center line AX. As shown in FIGS. 1 and 2, the guide member 300 has a first guide plate 310 and a second guide plate 320.

[0021] As shown by arrow AR1 in Figure 1, when the switching member 200 is in the first state, the first guide plate 310 guides the exhaust gas that has passed through the turbocharger mounting section 110 toward an area R1 of the catalyst 5 that is located on the opposite side (left side in Figure 1) from the side on which the turbocharger mounting section 110 is located, with the center line AX as the reference.

[0022] As shown by arrow AR2 in Figure 1, when the switching member 200 is in the first state, the second guide plate 320 guides the exhaust gas that has passed through the turbocharger mounting section 110 toward an area R2 that is located on the same side of the catalyst 5 as the turbocharger mounting section 110 (the right side in Figure 1) with respect to the center line AX.

[0023] 1, the first guide plate 310 and the second guide plate 320 have a shape that gradually moves away from the center line AX toward the downstream side in the flow direction. The second guide plate 320 may have a protruding portion 322 that protrudes further upstream in the flow direction than the first guide plate 310.

[0024] As described above, in the exhaust pipe structure 10 of this embodiment, the guide member 300 is disposed in the expanded portion 140 where exhaust gas is relatively likely to drift when the switching member 200 is in the first state, and guides the exhaust gas in a direction along the center line AX and in a direction toward the outside in the perpendicular direction, thereby suppressing the occurrence of exhaust gas drift in the expanded portion 140. This suppresses a decrease in the exhaust gas purification effect of the catalyst 5. In other words, the exhaust gas is effectively purified in the regions R1 and R2 as well. In addition, the guide member 300 increases the flow speed of the exhaust gas toward the regions R1 and R2, thereby suppressing the accumulation of deposits in the regions R1 and R2.

[0025] In the above embodiment, a so-called twin-turbo type internal combustion engine system in which the exhaust path 100 has a turbocharger mounting section 110 and another turbocharger mounting section 120 has been exemplified. However, the exhaust pipe structure 10 in the above embodiment is also applicable to a so-called single-turbo type internal combustion engine system, that is, a system in which the exhaust path 100 does not have another turbocharger mounting section 120 and only has the turbocharger mounting section 110.

[0026] Furthermore, the cross section of the guide member 300 in a plane perpendicular to the center line AX may be formed to be circular or elliptical.

[0027] [Aspects] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0028] An exhaust pipe structure according to one aspect of this disclosure comprises an exhaust path through which exhaust from an internal combustion engine flows, and a guide member provided within the exhaust path and guiding the exhaust toward a catalyst that purifies the exhaust, wherein the exhaust path has a turbocharger mounting section in which a turbocharger can be disposed, an enlarged section provided downstream of the turbocharger mounting section in the exhaust flow direction and in which the flow path area of ​​the exhaust gradually increases downstream in the exhaust flow direction, and a catalyst mounting section connected to the downstream end of the enlarged section and in which the catalyst is disposed, and the guide member is provided in the enlarged section and guides the exhaust in a direction along a center line including the central axis of the enlarged section, and in a direction toward the outside in a perpendicular direction perpendicular to the center line.

[0029] In this exhaust pipe structure, the guide member guides the exhaust gas in a direction along a center line including the central axis of the expanded portion and in a direction toward the outside in a direction perpendicular to the center line, thereby preventing the occurrence of a biased exhaust flow. This prevents the occurrence of exhaust stagnation in the catalyst arrangement portion or the expanded portion and the resulting accumulation of deposits near the stagnation, thereby preventing a decrease in the exhaust gas purification effect of the catalyst.

[0030] Moreover, the exhaust pipe structure may further include a switching member provided in the exhaust path. In this case, the exhaust path further includes an other turbocharger arrangement portion in which a turbocharger different from the turbocharger can be arranged and which is formed in parallel with the turbocharger arrangement portion, and a junction portion which is formed downstream of the turbocharger arrangement portion and the other turbocharger arrangement portion and upstream of the enlarged portion and which joins the exhaust gas that has passed through the turbocharger arrangement portion and the exhaust gas that has passed through the other turbocharger arrangement portion, and the switching member is switchable between a first state in which the exhaust gas flows only through the turbocharger arrangement portion and a second state in which the exhaust gas flows through both the turbocharger arrangement portion and the other turbocharger arrangement portion.

[0031] The guide member may have a first guide plate that guides the exhaust gas that has passed through the turbocharger mounting portion toward a side opposite to the side on which the turbocharger mounting portion is located with respect to the center line, and a second guide plate that guides the exhaust gas that has passed through the turbocharger mounting portion toward the same side on which the turbocharger mounting portion is located with respect to the center line. In this case, it is preferable that the first guide plate and the second guide plate have a shape that gradually moves away from the center line toward the downstream side in the flow direction.

[0032] In this aspect, even when only one turbocharger is driven in a so-called twin-turbo internal combustion engine system equipped with two turbochargers (when the switching member is in the first state), the occurrence of bias in the exhaust gas that has passed through the turbocharger mounting portion in the expansion portion is effectively suppressed.

[0033] The second guide plate may have a protruding portion that protrudes further upstream in the flow direction than the first guide plate.

[0034] In this way, when the switching member is in the first state, the flow rate of the exhaust gas guided by the protruding portion of the second guide plate toward the catalyst located on the second guide plate side of the center line increases, so that the exhaust gas is guided toward the catalyst more uniformly, thereby further enhancing the exhaust gas purification effect of the catalyst.

[0035] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0036] 1 internal combustion engine system, 2 internal combustion engine, 3 turbocharger (primary turbocharger), 4 other turbocharger (secondary turbocharger), 5 catalyst, 10 exhaust pipe structure, 100 exhaust path, 110 turbocharger arrangement section, 120 other turbocharger arrangement section, 130 junction section, 140 expansion section, 150 catalyst arrangement section, 200 switching member, 300 guide member, 310 first guide plate, 320 second guide plate.

Claims

[Claim 1] An exhaust path through which exhaust from the internal combustion engine flows; A switching member provided in the exhaust path; a guide member that is provided in the exhaust path and guides the exhaust gas toward a catalyst that purifies the exhaust gas, The exhaust path is a turbocharger mounting portion in which a turbocharger can be mounted; Another turbocharger arrangement section in which another turbocharger different from the turbocharger can be arranged and which is formed in parallel with the turbocharger arrangement section; an expansion section that is provided downstream of the turbocharger arrangement section in a flow direction of the exhaust gas, and in which a flow passage area of ​​the exhaust gas gradually increases toward the downstream in the flow direction; a junction section formed downstream of the turbocharger arrangement section and the other turbocharger arrangement section and upstream of the enlarged section, the junction section junctioning the exhaust gas that has passed through the turbocharger arrangement section and the exhaust gas that has passed through the other turbocharger arrangement section; a catalyst placement section connected to a downstream end of the expansion section and in which the catalyst is placed; the guide member is disposed in the expanded portion and guides the exhaust gas in a direction along a center line including a central axis of the expanded portion and in a direction toward an outside in a direction perpendicular to the center line, the switching member is switchable between a first state in which the exhaust gas flows only to the turbocharger mounting portion and a second state in which the exhaust gas flows to both the turbocharger mounting portion and the other turbocharger mounting portion, The guide member is a first guide plate that guides the exhaust gas that has passed through the turbocharger mounting portion toward an opposite side to a side on which the turbocharger mounting portion is located, with the center line as a reference; a second guide plate that guides the exhaust gas that has passed through the turbocharger arrangement portion toward the same side as the turbocharger arrangement portion with respect to the center line, the first guide plate and the second guide plate have a shape that gradually moves away from the center line toward a downstream side in the flow direction, the second guide plate has a protruding portion that protrudes upstream in the flow direction relative to the first guide plate.

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