Exhaust emission control device for internal combustion engine

Abstract

To promote diffusion of exhaust gas flowing into a catalytic converter and suppress stagnation of condensation water.SOLUTION: An exhaust emission control device 20 for an internal combustion engine 10 includes a connection part 40 comprising a first cylindrical part 41 connected to a catalytic converter 50 and a second cylindrical part 42 having an inner diameter larger than that of the first cylindrical part 41 and having a side surface to which an exhaust manifold 30 is connected. The connection part 40 is formed to have a shape in which the first cylindrical part 41 and the second cylindrical part 42 are connected with center axes thereof shifted from each other so that the center axis T1 of the first cylindrical part 41 is located on the vertical lower side of the center axis T2 of the second cylindrical part 42. The second cylindrical part 42 serves as a collision diffusion chamber 70 in which exhaust gas flowing from the exhaust manifold 30 is collided with a step 60 generated by a difference with the inner diameter of the first cylindrical part 41 and is diffused. The step 60 is not provided in a portion located on the vertical lower side of the collision diffusion chamber 70 with the internal combustion engine mounted.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an exhaust gas purification device for an internal combustion engine. [Background technology]

[0002] Patent Document 1 discloses an exhaust pipe structure in which a swirl flow generator is provided between each exhaust pipe of an exhaust manifold and a catalytic converter to collect exhaust gas flowing through each exhaust pipe and convert the exhaust flow into a swirl flow. With this exhaust pipe structure, the swirl flow generator converts the exhaust flow into a swirl flow, thereby diffusing the exhaust flow flowing into the catalytic converter. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-009793 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of the exhaust pipe structure disclosed in Patent Document 1, condensed water generated in the exhaust manifold flows into the swirl flow generator located below while the engine is running. The outlet that leads the exhaust to the catalytic converter is connected above the lowest part of the swirl flow generator. This raises concerns that condensed water may accumulate in the swirl flow generator. [Means for solving the problem]

[0005] The means for solving the above problems and their effects will be described below. According to one aspect of the present disclosure, there is provided an exhaust purification device for an internal combustion engine, comprising a connecting portion consisting of a first cylindrical portion connected to a catalytic converter and a second cylindrical portion having an inner diameter larger than that of the first cylindrical portion and having an exhaust manifold connected to its side, wherein the connecting portion is shaped so that the first cylindrical portion and the second cylindrical portion are connected with their central axes offset from each other so that the central axis of the first cylindrical portion is positioned vertically lower than the central axis of the second cylindrical portion, and the second cylindrical portion serves as an impingement diffusion chamber that causes exhaust flowing from the exhaust manifold to collide with a step created by the difference in inner diameter from the first cylindrical portion and diffuses the exhaust, and the step is not provided in a portion of the impingement diffusion chamber that is positioned vertically below when the internal combustion engine is installed, and the outlet of the exhaust manifold is located on the vertically lower side of the second cylindrical portion when the internal combustion engine is installed. [Effects of the Invention]

[0006] The exhaust gas purification device for an internal combustion engine can simultaneously promote the diffusion of exhaust gas flowing into a catalytic converter and suppress the accumulation of condensed water. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a top view of an exhaust gas purification device for an internal combustion engine according to an embodiment; [Figure 2] 2 is a side view of the exhaust gas purification device for an internal combustion engine as seen from the direction of arrow a in FIG. 1. [Figure 3] 2 is a front view of the exhaust gas purification device for an internal combustion engine as seen from the direction of arrow b in FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, one embodiment of an exhaust gas purification device for an internal combustion engine will be described with reference to FIGS. In the drawings, the width direction of the exhaust purification device 20 of the internal combustion engine 10 is referred to as the "left-right direction X," the length direction of the exhaust purification device 20 of the internal combustion engine 10, which is perpendicular to the width direction, is referred to as the "front-back direction Y," and the height direction of the exhaust purification device 20 of the internal combustion engine 10, which is perpendicular to both the width direction and the length direction, is referred to as the "up-down direction Z."

[0009] <Configuration of the exhaust gas purification device 20 of the internal combustion engine 10> FIG. 1 shows a schematic diagram of an exhaust gas purification device 20 for an internal combustion engine 10 mounted on a vehicle. As shown in FIG. 1, an exhaust purification device 20 for an internal combustion engine 10 includes an exhaust manifold 30, a cylindrical connection portion 40, and a cylindrical catalytic converter 50.

[0010] The exhaust manifold 30 is configured to guide the exhaust gas generated in the internal combustion engine 10 to the catalytic converter 50. In Figure 1, the direction in which the exhaust gas guided by the exhaust manifold 30 flows is indicated by a thick arrow.

[0011] The connecting portion 40 is a cylindrical portion that connects the exhaust manifold 30 and the catalytic converter 50. The connecting portion 40 includes a first cylindrical portion 41 and a second cylindrical portion . 2 and 3, the central axis T1 of the first cylindrical portion 41 and the central axis T2 of the second cylindrical portion 42 are located at different positions. The first cylindrical portion 41 and the second cylindrical portion 42 are connected such that the central axis T1 of the first cylindrical portion 41 is located vertically lower than the central axis T2 of the second cylindrical portion 42.

[0012] 1, connecting portion 40 connects to catalytic converter 50 at one end of its circular bottom surface, and connects to exhaust manifold 30 at the side of the cylinder. Since second cylindrical portion 42 has a larger inner diameter than first cylindrical portion 41, a step 60 is formed on the inner wall of connecting portion 40 due to the difference in inner diameter between first cylindrical portion 41 and second cylindrical portion 42.

[0013] The second cylindrical portion 42 is the impingement diffusion chamber 70, into which the exhaust gas flows through the exhaust manifold 30. The exhaust gas that flows into the impingement diffusion chamber 70 collides with the inner wall of the impingement diffusion chamber 70. The exhaust gas that collides with the inner wall of the impingement diffusion chamber 70 is diffused within the impingement diffusion chamber 70. The diffused exhaust gas flows into the catalytic converter 50 downstream. A portion of the diffused exhaust gas flows along the inner wall of the impingement diffusion chamber 70. At this time, the exhaust gas is redirected toward the center of the catalytic converter 50 by a step 60 provided on the inner wall of the connecting portion 40, and is diffused.

[0014] The catalytic converter 50 is configured to purify harmful components contained in the exhaust gas, such as carbon monoxide, hydrocarbons, and nitrogen oxides. The exhaust gas purified in the catalytic converter 50 is discharged from an exhaust outlet 80 of the catalytic converter 50. The exhaust outlet 80 is shown in FIG. 3.

[0015] As shown in FIGS. 2 and 3, the step 60 is not provided in the connecting portion 40 at a portion that is positioned vertically downward when the internal combustion engine is mounted. In Figure 3, the dashed dotted line indicates an imaginary line extending from the center line of the outlet of the exhaust manifold 30. As shown in Figure 3, the outlet of the exhaust manifold 30 is provided at the lower side of the connection part 40 in the vertical direction when the internal combustion engine is installed. A step 60 is provided in the same direction as the position where the exhaust gas that flows into the impingement diffusion chamber 70 along the dashed dotted line collides with the inner wall of the impingement diffusion chamber 70.

[0016] <Operation of this embodiment> As shown by the arrows in FIG. 1, the exhaust gas flowing in from the exhaust manifold 30 collides with the inner wall of the impingement diffusion chamber 70 and is redirected by the steps 60, thereby diffusing.

[0017] In this embodiment, the diffusion of exhaust gas is promoted by providing a step 60 on the inner wall of the connection portion 40. This allows the exhaust gas to reach the catalytic converter 50 without being biased in its flow.

[0018] Since the exhaust gas contains moisture, if the step 60 is provided along the entire periphery, including the vertically downward direction, condensed water may accumulate in the impingement diffusion chamber 70 in the exhaust gas purification device 20. In contrast to this, in this embodiment, the step 60 is not provided in the portion of the inner wall of the connection part 40 that is positioned vertically downward when the internal combustion engine is installed, thereby making it possible to prevent condensed water from accumulating in the impingement diffusion chamber 70.

[0019] <Effects of this embodiment> (1) The exhaust gas purification device 20 can simultaneously promote the diffusion of exhaust gas flowing into the catalytic converter 50 and prevent condensed water from accumulating.

[0020] (2) In the exhaust purification device 20 of the internal combustion engine 10, a step 60 is provided on the inner wall of the connection portion 40 located in the same direction as the position where the exhaust gas flowing from the exhaust manifold 30 collides with the inner wall of the collision diffusion chamber 70, in a direction centered on the central axis T2 of the second cylindrical portion 42.

[0021] The exhaust gas that flows into the impingement diffusion chamber 70 is guided along the inner wall of the impingement diffusion chamber 70 to the catalytic converter 50. In the exhaust gas purification device 20 of this embodiment, a step 60 is provided on the inner wall of the connection part 40 in the same direction as the position where the exhaust gas collides with the inner wall of the impingement diffusion chamber 70, thereby facilitating the diffusion of the exhaust gas.

[0022] (3) In the exhaust purification device 20 for the internal combustion engine 10, the outlet of the exhaust manifold 30 is provided at the lower side of the connection portion 40 in the vertical direction when the internal combustion engine is mounted. In an exhaust purification device 20 for an internal combustion engine 10 in which a step 60 is not provided in the portion of the inner wall of the connection portion 40 that is located vertically below when the internal combustion engine is installed, if exhaust gas flows in from the vertically upper side when the internal combustion engine is installed, the exhaust gas will not be sufficiently diffused.

[0023] In contrast to this, in this embodiment, the outlet of the exhaust manifold 30 is provided at the connecting portion 40 on the vertically lower side when the internal combustion engine is installed. This causes the exhaust to collide with the inner wall of the impingement diffusion chamber 70 on the vertically upper side when the internal combustion engine is installed. Therefore, the step 60 can diffuse the exhaust.

[0024] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0025] The exhaust purification device 20 for the internal combustion engine 10 does not need to be provided with a step 60 that blocks the flow of condensed water from the second cylindrical portion 42 to the first cylindrical portion 41 in a portion of the impingement diffusion chamber 70 that is located vertically below the impingement diffusion chamber 70 when the internal combustion engine is installed. For example, the lower surface of the first cylindrical portion 41 may be located lower than the lower surface of the second cylindrical portion 42 when the internal combustion engine is installed.

[0026] Although the example in which the diameter of the connecting portion 40 is smaller than the diameter of the catalytic converter 50 has been shown, the diameter of the catalytic converter 50 and the diameter of the connecting portion 40 may be the same. [Explanation of symbols]

[0027] 10...internal combustion engine, 20...exhaust purification device, 30...exhaust manifold, 40...connection portion, 41...first cylindrical portion, 42...second cylindrical portion, 50...catalytic converter, 60...step, 70...impingement diffusion chamber, 80...exhaust outlet, T1...center axis of first cylindrical portion, T2...center axis of second cylindrical portion

Claims

[Claim 1] a connecting portion including a first cylindrical portion connected to a catalytic converter and a second cylindrical portion having an inner diameter larger than that of the first cylindrical portion and having an exhaust manifold connected to a side surface thereof; the connecting portion is shaped so that the first cylindrical portion and the second cylindrical portion are connected with their central axes shifted from each other such that the central axis of the first cylindrical portion is positioned vertically lower than the central axis of the second cylindrical portion, The second cylindrical portion serves as an impingement diffusion chamber in which the exhaust gas flowing from the exhaust manifold is caused to impinge on a step formed by a difference in inner diameter between the second cylindrical portion and the first cylindrical portion, and is diffused. The step is not provided in a portion of the impingement diffusion chamber that is positioned vertically downward when the internal combustion engine is installed, An outlet of the exhaust manifold is provided on a vertically lower side of the second cylindrical portion when the internal combustion engine is mounted. Exhaust gas purification device for internal combustion engines.

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